WorldWideScience

Sample records for gated closed conduits

  1. Automatically closing swing gate closure assembly

    Science.gov (United States)

    Chang, Shih-Chih; Schuck, William J.; Gilmore, Richard F.

    1988-01-01

    A swing gate closure assembly for nuclear reactor tipoff assembly wherein the swing gate is cammed open by a fuel element or spacer but is reliably closed at a desired closing rate primarily by hydraulic forces in the absence of a fuel charge.

  2. Impact of asymmetric lamp positioning on the performance of a closed-conduit UV reactor

    Directory of Open Access Journals (Sweden)

    Tipu Sultan

    2017-06-01

    Full Text Available Computational fluid dynamics (CFD analyses for the performance improvement of a closed-conduit ultraviolet (UV reactor were performed by changing the lamp positions from symmetric to asymmetric. The asymmetric lamp positioning can be useful for UV reactor design and optimization. This goal was achieved by incorporating the two performance factors, namely reduction equivalent dose (RED and system dose performance. Four cases were carried out for asymmetric lamp positioning within the UV reactor chamber and each case consisted of four UV lamps that were simulated once symmetrically and four times asymmetrically. The results of the four asymmetric cases were compared with the symmetric one. Moreover, these results were evaluated by using CFD simulations of a closed-conduit UV reactor. The fluence rate model, UVCalc3D was employed to validate the simulations results. The simulation results provide detailed information about the dose distribution, pathogen track modeling and RED. The RED value was increased by approximately 15% by using UVCalc3D fluence rate model. Additionally, the asymmetric lamp positioning of the UV lamps had more than 50% of the pathogens received a better and a higher UV dose than in the symmetric case. Consequently, the system dose performance was improved by asymmetric lamp positioning. It was concluded that the performance parameters (higher RED and system dose performance were improved by using asymmetric lamp positioning.

  3. Flow-rate measurements in closed-conduits by tracer techniques

    International Nuclear Information System (INIS)

    Lund Plantat, C.

    1982-01-01

    This paper presents the study of the precision obtained measuring flow-rates in closed-conduits by tracer techniques. The flow-rates analyzed were in the range of 10 to 20 l/s and Reynolds numbers from 10 5 to 2 x 10 5 . Tracer used were fluoresceine and In-113 m; and the measurements were performed with the dilution method (punctual and continuous injection) and the Allen method. Precisions for the method of punctual and continuous injections were 6.25% and 9.45% for fluoresceine and 9.3% and 3% for In-113, respectively. For Allen method with In-113 m a precision of 5% was obtained; probably this value was affected by the short distance between detectors. In all cases the error corresponds with the expected value except in one measurement at a 68.3% confidence level. (I.V.)

  4. Gating of Connexin Channels by transjunctional-voltage: Conformations and models of open and closed states.

    Science.gov (United States)

    Bargiello, Thaddeus A; Oh, Seunghoon; Tang, Qingxiu; Bargiello, Nicholas K; Dowd, Terry L; Kwon, Taekyung

    2018-01-01

    Voltage is an important physiologic regulator of channels formed by the connexin gene family. Connexins are unique among ion channels in that both plasma membrane inserted hemichannels (undocked hemichannels) and intercellular channels (aggregates of which form gap junctions) have important physiological roles. The hemichannel is the fundamental unit of gap junction voltage-gating. Each hemichannel displays two distinct voltage-gating mechanisms that are primarily sensitive to a voltage gradient formed along the length of the channel pore (the transjunctional voltage) rather than sensitivity to the absolute membrane potential (V m or V i-o ). These transjunctional voltage dependent processes have been termed V j - or fast-gating and loop- or slow-gating. Understanding the mechanism of voltage-gating, defined as the sequence of voltage-driven transitions that connect open and closed states, first and foremost requires atomic resolution models of the end states. Although ion channels formed by connexins were among the first to be characterized structurally by electron microscopy and x-ray diffraction in the early 1980's, subsequent progress has been slow. Much of the current understanding of the structure-function relations of connexin channels is based on two crystal structures of Cx26 gap junction channels. Refinement of crystal structure by all-atom molecular dynamics and incorporation of charge changing protein modifications has resulted in an atomic model of the open state that arguably corresponds to the physiologic open state. Obtaining validated atomic models of voltage-dependent closed states is more challenging, as there are currently no methods to solve protein structure while a stable voltage gradient is applied across the length of an oriented channel. It is widely believed that the best approach to solve the atomic structure of a voltage-gated closed ion channel is to apply different but complementary experimental and computational methods and to use

  5. Flexible cryogenic conduit

    International Nuclear Information System (INIS)

    Brindza, P.D.; Wines, R.R.; Takacs, J.J.

    1999-01-01

    A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament

  6. A limited 4 Å radial displacement of the S4-S5 linker is sufficient for internal gate closing in Kv channels.

    Science.gov (United States)

    Faure, Élise; Starek, Greg; McGuire, Hugo; Bernèche, Simon; Blunck, Rikard

    2012-11-16

    Voltage-gated ion channels are responsible for the generation of action potentials in our nervous system. Conformational rearrangements in their voltage sensor domains in response to changes of the membrane potential control pore opening and thus ion conduction. Crystal structures of the open channel in combination with a wealth of biophysical data and molecular dynamics simulations led to a consensus on the voltage sensor movement. However, the coupling between voltage sensor movement and pore opening, the electromechanical coupling, occurs at the cytosolic face of the channel, from where no structural information is available yet. In particular, the question how far the cytosolic pore gate has to close to prevent ion conduction remains controversial. In cells, spectroscopic methods are hindered because labeling of internal sites remains difficult, whereas liposomes or detergent solutions containing purified ion channels lack voltage control. Here, to overcome these problems, we controlled the state of the channel by varying the lipid environment. This way, we directly measured the position of the S4-S5 linker in both the open and the closed state of a prokaryotic Kv channel (KvAP) in a lipid environment using Lanthanide-based resonance energy transfer. We were able to reconstruct the movement of the covalent link between the voltage sensor and the pore domain and used this information as restraints for molecular dynamics simulations of the closed state structure. We found that a small decrease of the pore radius of about 3-4 Å is sufficient to prevent ion permeation through the pore.

  7. Sealing a conduit end

    International Nuclear Information System (INIS)

    Mentz, R.M.

    1993-01-01

    An apparatus for sealing or blocking conduits, such as the primary nozzles of a nuclear steam generator is described. It includes an annular bracket sealingly attached to the open end of the nozzle, the bracket having a plurality of threaded holes therein. Mounted atop the bracket is a generally circular nozzle dam for covering the opening. Interposed between the nozzle dam and the bracket is an extrusion-resistant seal member having a plurality of apertures therethrough for receiving each bolt. The seal member is configured to resist extrusion by having laminated layers of differing hardnesses, so that the seal member will not laterally extrude away from each bolt in a manner that enlarges the aperture surrounding each bolt as the nozzle dam is bolted to the bracket. (author)

  8. Open or close the gate – stomata action under the control of phytohormones in drought stress conditions

    Directory of Open Access Journals (Sweden)

    Agata eDaszkowska-Golec

    2013-05-01

    Full Text Available Two highly specialized cells, the guard cells that surround the stomatal pore, are able to integrate environmental and endogenous signals in order to control the stomatal aperture and thereby the gas exchange. The uptake of CO2 is associated with a loss of water by leaves. Control of the size of the stomatal aperture optimizes the efficiency of water use through dynamic changes in the turgor of the guard cells. The opening and closing of stomata is regulated by the integration of environmental signals and endogenous hormonal stimuli. The various different factors to which the guard cells respond translates into the complexity of the network of signaling pathways that control stomatal movements. The perception of an abiotic stress triggers the activation of signal transduction cascades that interact with or are activated by phytohormones. Among these, abscisic acid (ABA, is the best-known stress hormone that closes the stomata, although other phytohormones, such as jasmonic acid, brassinosteroids, cytokinins or ethylene are also involved in the stomatal response to stresses. As a part of the drought response, ABA may interact with jasmonic acid and nitric oxide in order to stimulate stomatal closure. In addition, the regulation of gene expression in response to ABA involves genes that are related to ethylene, cytokinins and auxin signaling. In this paper, recent findings on phytohormone crosstalk, changes in signaling pathways including the expression of specific genes and their impact on modulating stress response through the closing or opening of stomata, together with the highlights of gaps that need to be elucidated in the signaling network of stomatal regulation, are reviewed.

  9. Peripheral nerve conduits: technology update

    Science.gov (United States)

    Arslantunali, D; Dursun, T; Yucel, D; Hasirci, N; Hasirci, V

    2014-01-01

    Peripheral nerve injury is a worldwide clinical problem which could lead to loss of neuronal communication along sensory and motor nerves between the central nervous system (CNS) and the peripheral organs and impairs the quality of life of a patient. The primary requirement for the treatment of complete lesions is a tension-free, end-to-end repair. When end-to-end repair is not possible, peripheral nerve grafts or nerve conduits are used. The limited availability of autografts, and drawbacks of the allografts and xenografts like immunological reactions, forced the researchers to investigate and develop alternative approaches, mainly nerve conduits. In this review, recent information on the various types of conduit materials (made of biological and synthetic polymers) and designs (tubular, fibrous, and matrix type) are being presented. PMID:25489251

  10. The corrosion effect on the conduit systems

    International Nuclear Information System (INIS)

    Laaidi, Naouar; Belattar, Sougratti

    2009-01-01

    The conduits in the buildings require a regular and permanent control, in order to avoid the risks of deterioration caused by the corrosion or the escape of water. In this work, we present a thermal nondestructive testing method of concrete structures containing water conduits, based on numerical modeling in three dimensions. The goal is to study the detectability of these conduits in different situations and to give a thermal characterization of the rust behaviour in the steel conduits. (author)

  11. 3D-engineering of Cellularized Conduits for Peripheral Nerve Regeneration

    Science.gov (United States)

    Hu, Yu; Wu, Yao; Gou, Zhiyuan; Tao, Jie; Zhang, Jiumeng; Liu, Qianqi; Kang, Tianyi; Jiang, Shu; Huang, Siqing; He, Jiankang; Chen, Shaochen; Du, Yanan; Gou, Maling

    2016-08-01

    Tissue engineered conduits have great promise for bridging peripheral nerve defects by providing physical guiding and biological cues. A flexible method for integrating support cells into a conduit with desired architectures is wanted. Here, a 3D-printing technology is adopted to prepare a bio-conduit with designer structures for peripheral nerve regeneration. This bio-conduit is consisted of a cryopolymerized gelatin methacryloyl (cryoGelMA) gel cellularized with adipose-derived stem cells (ASCs). By modeling using 3D-printed “lock and key” moulds, the cryoGelMA gel is structured into conduits with different geometries, such as the designed multichannel or bifurcating and the personalized structures. The cryoGelMA conduit is degradable and could be completely degraded in 2-4 months in vivo. The cryoGelMA scaffold supports the attachment, proliferation and survival of the seeded ASCs, and up-regulates the expression of their neurotrophic factors mRNA in vitro. After implanted in a rat model, the bio-conduit is capable of supporting the re-innervation across a 10 mm sciatic nerve gap, with results close to that of the autografts in terms of functional and histological assessments. The study describes an indirect 3D-printing technology for fabricating cellularized designer conduits for peripheral nerve regeneration, and could lead to the development of future nerve bio-conduits for clinical use.

  12. Programming the quorum sensing-based AND gate in Shewanella oneidensis for logic gated-microbial fuel cells.

    Science.gov (United States)

    Hu, Yidan; Yang, Yun; Katz, Evgeny; Song, Hao

    2015-03-11

    An AND logic gate based on a synthetic quorum-sensing (QS) module was constructed in a Shewanella oneidensis MR-1 mtrA knockout mutant. The presence of two input signals activated the expression of a periplasmic decaheme cytochrome MtrA to regenerate the extracellular electron transfer conduit, enabling the construction of AND-gated microbial fuel cells.

  13. Peripheral nerve conduits: technology update

    Directory of Open Access Journals (Sweden)

    Arslantunali D

    2014-12-01

    Full Text Available D Arslantunali,1–3,* T Dursun,1,2,* D Yucel,1,4,5 N Hasirci,1,2,6 V Hasirci,1,2,7 1BIOMATEN, Center of Excellence in Biomaterials and Tissue Engineering, Middle East Technical University (METU, Ankara, Turkey; 2Department of Biotechnology, METU, Ankara, Turkey; 3Department of Bioengineering, Gumushane University, Gumushane, Turkey; 4Faculty of Engineering, Department of Medical Engineering, Acibadem University, Istanbul, Turkey; 5School of Medicine, Department of Histology and Embryology, Acibadem University, Istanbul, Turkey; 6Department of Chemistry, Faculty of Arts and Sciences, METU, Ankara, Turkey; 7Department of Biological Sciences, Faculty of Arts and Sciences, METU, Ankara, Turkey *These authors have contributed equally to this work Abstract: Peripheral nerve injury is a worldwide clinical problem which could lead to loss of neuronal communication along sensory and motor nerves between the central nervous system (CNS and the peripheral organs and impairs the quality of life of a patient. The primary requirement for the treatment of complete lesions is a tension-free, end-to-end repair. When end-to-end repair is not possible, peripheral nerve grafts or nerve conduits are used. The limited availability of autografts, and drawbacks of the allografts and xenografts like immunological reactions, forced the researchers to investigate and develop alternative approaches, mainly nerve conduits. In this review, recent information on the various types of conduit materials (made of biological and synthetic polymers and designs (tubular, fibrous, and matrix type are being presented. Keywords: peripheral nerve injury, natural biomaterials, synthetic biomaterials

  14. Signatures of Mechanosensitive Gating.

    Science.gov (United States)

    Morris, Richard G

    2017-01-10

    The question of how mechanically gated membrane channels open and close is notoriously difficult to address, especially if the protein structure is not available. This perspective highlights the relevance of micropipette-aspirated single-particle tracking-used to obtain a channel's diffusion coefficient, D, as a function of applied membrane tension, σ-as an indirect assay for determining functional behavior in mechanosensitive channels. While ensuring that the protein remains integral to the membrane, such methods can be used to identify not only the gating mechanism of a protein, but also associated physical moduli, such as torsional and dilational rigidity, which correspond to the protein's effective shape change. As an example, three distinct D-versus-σ "signatures" are calculated, corresponding to gating by dilation, gating by tilt, and gating by a combination of both dilation and tilt. Both advantages and disadvantages of the approach are discussed. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  15. Conduit for regeneration of biological material

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a conduit comprising a first material, having 1) a through-going hole, 2) fibers aligned along the long-axis in the through-going hole, each fiber having a diameter in the range 200-2000 nm. The conduit is preferably for regeneration of biological material, even...

  16. 47 CFR 32.2441 - Conduit systems.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Conduit systems. 32.2441 Section 32.2441 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES UNIFORM SYSTEM OF ACCOUNTS FOR TELECOMMUNICATIONS COMPANIES Instructions for Balance Sheet Accounts § 32.2441 Conduit systems. (a...

  17. Long-term monitoring on a closed-conduit volcano: A 25 year long time-series of temperatures recorded at La Fossa cone (Vulcano Island, Italy), ranging from 250 °C to 520 °C

    Science.gov (United States)

    Diliberto, Iole Serena

    2017-10-01

    The longest record of temperature data from an active volcano in southern Italy is presented. The dataset comes from continuous monitoring of fumarole temperatures from the La Fossa cone of Vulcano (Aeolian Islands) running from 1991 to 2016. The discussion includes an empirical approach, based on a large number of direct measurements. At Vulcano Island, geochemical monitoring of the uprising fluids allows detection of the surface effects of perturbation in the state variables of the buried hydrothermal and magmatic systems. The presented datasets show that fumaroles' changing temperatures, which are related to surface heat flow, are useful indicators. Over the past 25 years, the combined effects of runoff and chemo-physical alterations were negligible on the output temperature of the earliest monitored fumaroles. The maximum recorded variation was 298 °C (measured in the ground very close to the steaming vents, at a depth of 0.5 m). Repetition of output temperature values occurred after 19 years in the same position; the time variations suggest a cyclic characteristic, although more years are needed to register the complete cyclic modulation. A combination of minor cyclical variations has also been registered in the fumarole output. The minor cycles appeared in this long series of data after 1995, and they can be interpreted as one of the surface effects of temporary departures from a stationary state assumed for the system feeding the La Fossa area. In this sector of the Mediterranean area, the steady state pressure field, as well as the steady state temperature gradients, can be perturbed either by magmatism or by seismo-tectonic processes related to regional dynamics. This long-term monitoring allowed comparisons of many temperature subsets with other validated geochemical and geophysical data series and highlighted common source mechanisms accounting for endogenous processes. Changes in the magma source and/or seismo-tectonic activity have been the primary

  18. Bentall Operation with Valved Homograft Conduit

    Science.gov (United States)

    Choudhary, Shiv K.; Talwar, Sachin; Kumar, A. Sampath

    2000-01-01

    Lesions of the ascending aorta associated with aortic valve disease are usually treated by implanting a prosthetic valved conduit (Bentall procedure). In this report, we present our experience in which a valved homograft conduit was used for the procedure. Six patients underwent a Bentall procedure with the use of a cryopreserved valved homograft conduit. Two of the patients had annuloaortic ectasia, 2 had Marfan syndrome, and 1 had an atherosclerotic aneurysm of the aorta. One patient had severe aortic stenosis due to a bicuspid aortic valve, along with an aneurysm and localized dissection of the ascending aorta. In all of the patients, the aortic annulus was substantially dilated, with accompanying moderate-to-severe aortic regurgitation. A standard procedure was performed with moderate hypothermia, cardiopulmonary bypass, and aortic and bicaval cannulation. The ascending aorta and the aortic valve were replaced with a cryopreserved valved homograft conduit (aortic in 5 patients and pulmonary in 1). The native coronary ostia were anastomosed directly to the homograft. Echocardiography, which was performed intraoperatively, before discharge from the hospital, and at follow-up visits (1 to 36 months), revealed good valve function without dilatation of the homograft conduits. There was 1 late death due to Aspergillus fumigatus endocarditis, 6 months postoperatively. In 1 patient, magnetic resonance imaging performed at 24 months revealed normal caliber of the homograft conduit. We conclude that the Bentall procedure can be performed, safely and with excellent results, using cryopreserved homograft conduits. PMID:11198310

  19. Conduit enlargement in an eogenetic karst aquifer

    Science.gov (United States)

    Moore, Paul J.; Martin, Jonathan B.; Screaton, Elizabeth J.; Neuhoff, Philip S.

    2010-11-01

    SummaryMost concepts of conduit development have focused on telogenetic karst aquifers, where low matrix permeability focuses flow and dissolution along joints, fractures, and bedding planes. However, conduits also exist in eogenetic karst aquifers, despite high matrix permeability which accounts for a significant component of flow. This study investigates dissolution within a 6-km long conduit system in the eogenetic Upper Floridan aquifer of north-central Florida that begins with a continuous source of allogenic recharge at the Santa Fe River Sink and discharges from a first-magnitude spring at the Santa Fe River Rise. Three sources of water to the conduit include the allogenic recharge, diffuse recharge through epikarst, and mineralized water upwelling from depth. Results of sampling and inverse modeling using PHREEQC suggest that dissolution within the conduit is episodic, occurring only during 30% of 16 sampling times between March 2003 and April 2007. During low flow conditions, carbonate saturated water flows from the matrix to the conduit, restricting contact between undersaturated allogenic water with the conduit wall. When gradients reverse during high flow conditions, undersaturated allogenic recharge enters the matrix. During these limited periods, estimates of dissolution within the conduit suggest wall retreat averages about 4 × 10 -6 m/day, in agreement with upper estimates of maximum wall retreat for telogenetic karst. Because dissolution is episodic, time-averaged dissolution rates in the sink-rise system results in a wall retreat rate of about 7 × 10 -7 m/day, which is at the lower end of wall retreat for telogenetic karst. Because of the high permeability matrix, conduits in eogenetic karst thus enlarge not just at the walls of fractures or pre-existing conduits such as those in telogenetic karst, but also may produce a friable halo surrounding the conduits that may be removed by additional mechanical processes. These observations stress the

  20. Stochastic simulation of karst conduit networks

    Science.gov (United States)

    Pardo-Igúzquiza, Eulogio; Dowd, Peter A.; Xu, Chaoshui; Durán-Valsero, Juan José

    2012-01-01

    Karst aquifers have very high spatial heterogeneity. Essentially, they comprise a system of pipes (i.e., the network of conduits) superimposed on rock porosity and on a network of stratigraphic surfaces and fractures. This heterogeneity strongly influences the hydraulic behavior of the karst and it must be reproduced in any realistic numerical model of the karst system that is used as input to flow and transport modeling. However, the directly observed karst conduits are only a small part of the complete karst conduit system and knowledge of the complete conduit geometry and topology remains spatially limited and uncertain. Thus, there is a special interest in the stochastic simulation of networks of conduits that can be combined with fracture and rock porosity models to provide a realistic numerical model of the karst system. Furthermore, the simulated model may be of interest per se and other uses could be envisaged. The purpose of this paper is to present an efficient method for conditional and non-conditional stochastic simulation of karst conduit networks. The method comprises two stages: generation of conduit geometry and generation of topology. The approach adopted is a combination of a resampling method for generating conduit geometries from templates and a modified diffusion-limited aggregation method for generating the network topology. The authors show that the 3D karst conduit networks generated by the proposed method are statistically similar to observed karst conduit networks or to a hypothesized network model. The statistical similarity is in the sense of reproducing the tortuosity index of conduits, the fractal dimension of the network, the direction rose of directions, the Z-histogram and Ripley's K-function of the bifurcation points (which differs from a random allocation of those bifurcation points). The proposed method (1) is very flexible, (2) incorporates any experimental data (conditioning information) and (3) can easily be modified when

  1. Linear gate

    International Nuclear Information System (INIS)

    Suwono.

    1978-01-01

    A linear gate providing a variable gate duration from 0,40μsec to 4μsec was developed. The electronic circuity consists of a linear circuit and an enable circuit. The input signal can be either unipolar or bipolar. If the input signal is bipolar, the negative portion will be filtered. The operation of the linear gate is controlled by the application of a positive enable pulse. (author)

  2. Pumped Storage and Potential Hydropower from Conduits

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2015-02-25

    Th is Congressional Report, Pumped Storage Hydropower and Potential Hydropower from Conduits, addresses the technical flexibility that existing pumped storage facilities can provide to support intermittent renewable energy generation. This study considered potential upgrades or retrofit of these facilities, the technical potential of existing and new pumped storage facilities to provide grid reliability benefits, and the range of conduit hydropower opportunities available in the United States.

  3. VLP seismicity from resonant modes of acoustic-gravity waves in a conduit-crack system filled with multiphase magma

    Science.gov (United States)

    Liang, C.; Prochnow, B. N.; OReilly, O. J.; Dunham, E. M.; Karlstrom, L.

    2016-12-01

    Oscillation of magma in volcanic conduits connected to cracks (dikes and sills) has been suggested as an explanation for very long period (VLP) seismic signals recorded at active basaltic volcanoes such as. Kilauea, Hawaii, and Erebus, Antarctica. We investigate the VLP seismicity using a linearized model for waves in and associated eigenmodes of a coupled conduit-crack system filled with multiphase magma, an extension of the Karlstrom and Dunham (2016) model for acoustic-gravity waves in volcanic conduits. We find that the long period surface displacement (as recorded on broadband seismometers) is dominated by opening/closing of the crack rather than the deformation of the conduit conduit walls. While the fundamental eigenmode is sensitive to the fluid properties and the geometry of the magma plumbing system, a closer scrutiny of various resonant modes reveals that the surface displacement is often more sensitive to higher modes. Here we present a systematic analysis of various long period acoustic-gravity wave resonant modes of a coupled conduit-crack system that the surface displacement is most sensitive to. We extend our previous work on a quasi-one-dimensional conduit model with inviscid magma to a more general axisymmetric conduit model that properly accounts for viscous boundary layers near the conduit walls, based on the numerical method developed by Prochnow et al. (submitted to Computers and Fluids, 2016). The surface displacement is dominated by either the fundamental or higher eigenmodes, depending on magma properties and the geometry of conduit and crack. An examination of the energetics of these modes reveals the complex interplay of different restoring forces (magma compressibility in the conduit, gravity, and elasticity of the crack) driving the VLP oscillations. Both nonequilibrium bubble growth and resorption and viscosity contribute to the damping of VLP signals. Our models thus provide a means to infer properties of open-vent basaltic volcanoes

  4. Conduit Stability and Collapse in Explosive Volcanic Eruptions: Coupling Conduit Flow and Failure Models

    Science.gov (United States)

    Mullet, B.; Segall, P.

    2017-12-01

    Explosive volcanic eruptions can exhibit abrupt changes in physical behavior. In the most extreme cases, high rates of mass discharge are interspaced by dramatic drops in activity and periods of quiescence. Simple models predict exponential decay in magma chamber pressure, leading to a gradual tapering of eruptive flux. Abrupt changes in eruptive flux therefore indicate that relief of chamber pressure cannot be the only control of the evolution of such eruptions. We present a simplified physics-based model of conduit flow during an explosive volcanic eruption that attempts to predict stress-induced conduit collapse linked to co-eruptive pressure loss. The model couples a simple two phase (gas-melt) 1-D conduit solution of the continuity and momentum equations with a Mohr-Coulomb failure condition for the conduit wall rock. First order models of volatile exsolution (i.e. phase mass transfer) and fragmentation are incorporated. The interphase interaction force changes dramatically between flow regimes, so smoothing of this force is critical for realistic results. Reductions in the interphase force lead to significant relative phase velocities, highlighting the deficiency of homogenous flow models. Lateral gas loss through conduit walls is incorporated using a membrane-diffusion model with depth dependent wall rock permeability. Rapid eruptive flux results in a decrease of chamber and conduit pressure, which leads to a critical deviatoric stress condition at the conduit wall. Analogous stress distributions have been analyzed for wellbores, where much work has been directed at determining conditions that lead to wellbore failure using Mohr-Coulomb failure theory. We extend this framework to cylindrical volcanic conduits, where large deviatoric stresses can develop co-eruptively leading to multiple distinct failure regimes depending on principal stress orientations. These failure regimes are categorized and possible implications for conduit flow are discussed, including

  5. Extreme loads seismic testing of conduit systems

    International Nuclear Information System (INIS)

    Howard, G.E.; Ibanez, P.; Harrison, S.; Shi, Z.T.

    1991-01-01

    Rigid steel conduit (thin-wall tubes with threaded connections) containing electrical cabling are a common feature in nuclear power plants. Conduit systems are in many cases classified in U.S.A. practice as Seismic Category I structures. this paper summarizes results and others aspects of a dynamic test program conducted to investigate conduit systems seismic performance under three-axis excitation for designs representative at a nuclear power plant sited near Ft. Worth, Texas (a moderate seismic zone), with a Safe Shutdown Earthquake (SSE) of 0.12 g. Test specimens where subjected to postulated seismic events, including excitation well in excess of Safe Shutdown Earthquake events typical for U.S.A. nuclear power stations. A total of 18 conduit systems of 9-meter nominal lengths were shake table mounted and subjected to a variety of tests. None of the specimens suffered loss of load capacity when subjected to a site-enveloping Safe Shutdown Earthquake (SSE). Clamp/attachment hardware failures only began to occur when earthquake input motion was scaled upward to minimum values of 2.3-4.6 times site enveloping SSE response spectra. Tensile and/or shear failure of clamp attachment bolts or studs was the failure mode in all case in which failure was induced. (author)

  6. Drill pipes and casings utilizing multi-conduit tubulars

    Energy Technology Data Exchange (ETDEWEB)

    Curlett, H.B.

    1989-01-24

    A seal adapted for use with a multi-conduit well tubular, or the like, is described which consists of: a plate with fluid passages, each passage corresponding to an opening of a conduit of the multiconduit tubular, and a groove on the plate around each passage; and elastomer means partially embeddable into each groove for sealing each conduit of a tubular to a corresponding conduit of another similar tubular.

  7. Latest design of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  8. Genipin-Cross-Linked Chitosan Nerve Conduits Containing TNF-α Inhibitors for Peripheral Nerve Repair.

    Science.gov (United States)

    Zhang, Li; Zhao, Weijia; Niu, Changmei; Zhou, Yujie; Shi, Haiyan; Wang, Yalin; Yang, Yumin; Tang, Xin

    2018-07-01

    Tissue engineered nerve grafts (TENGs) are considered a promising alternative to autologous nerve grafting, which is considered the "gold standard" clinical strategy for peripheral nerve repair. Here, we immobilized tumor necrosis factor-α (TNF-α) inhibitors onto a nerve conduit, which was introduced into a chitosan (CS) matrix scaffold utilizing genipin (GP) as the crosslinking agent, to fabricate CS-GP-TNF-α inhibitor nerve conduits. The in vitro release kinetics of TNF-α inhibitors from the CS-GP-TNF-α inhibitor nerve conduits were investigated using high-performance liquid chromatography. The in vivo continuous release profile of the TNF-α inhibitors released from the CS-GP-TNF-α inhibitor nerve conduits was measured using an enzyme-linked immunosorbent assay over 14 days. We found that the amount of TNF-α inhibitors released decreased with time after the bridging of the sciatic nerve defects in rats. Moreover, 4 and 12 weeks after surgery, histological analyses and functional evaluations were carried out to assess the influence of the TENG on regeneration. Immunochemistry performed 4 weeks after grafting to assess early regeneration outcomes revealed that the TENG strikingly promoted axonal outgrowth. Twelve weeks after grafting, the TENG accelerated myelin sheath formation, as well as functional restoration. In general, the regenerative outcomes following TENG more closely paralleled findings observed with autologous grafting than the use of the CS matrix scaffold. Collectively, our data indicate that the CS-GP-TNF-α inhibitor nerve conduits comprised an elaborate system for sustained release of TNF-α inhibitors in vitro, while studies in vivo demonstrated that the TENG could accelerate regenerating axonal outgrowth and functional restoration. The introduction of CS-GP-TNF-α-inhibitor nerve conduits into a scaffold may contribute to an efficient and adaptive immune microenvironment that can be used to facilitate peripheral nerve repair.

  9. A high performance gate drive for large gate turn off thyristors

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, C.P.

    1993-01-01

    Past approaches to gate turn-off (GTO) gating are application oriented, inefficient and dissipate power even when inactive. They allow the gate to avalanch, and do not reduce GTO turn-on and turn-off losses. A new approach is proposed which will allow modular construction and adaptability to large GTOs in the 50 amp to 2000 amp range. The proposed gate driver can be used in large voltage source and current source inverters and other power converters. The approach consists of a power metal-oxide-silicon field effect transistor (MOSFET) technology gating unit, with associated logic and supervisory circuits and an isolated flyback converter as the dc power source for the gating unit. The gate driver formed by the gating unit and the flyback converter is designed for 4000 V isolation. Control and supervisory signals are exchanged between the gate driver and the remote control system via fiber optics. The gating unit has programmable front-porch current amplitude and pulse-width, programmable closed-loop controlled back-porch current, and a turn-off switch capable of supplying negative gate current at demand as a function of peak controllable forward anode current. The GTO turn-on, turn-off and gate avalanch losses are reduced to a minimum. The gate driver itself has minimum operating losses. Analysis, design and practical realization are reported. 19 refs., 54 figs., 1 tab.

  10. Sliding-gate valve for use with abrasive materials

    Science.gov (United States)

    Ayers, Jr., William J.; Carter, Charles R.; Griffith, Richard A.; Loomis, Richard B.; Notestein, John E.

    1985-01-01

    The invention is a flow and pressure-sealing valve for use with abrasive solids. The valve embodies special features which provide for long, reliable operating lifetimes in solids-handling service. The valve includes upper and lower transversely slidable gates, contained in separate chambers. The upper gate provides a solids-flow control function, whereas the lower gate provides a pressure-sealing function. The lower gate is supported by means for (a) lifting that gate into sealing engagement with its seat when the gate is in its open and closed positions and (b) lowering the gate out of contact with its seat to permit abrasion-free transit of the gate between its open and closed positions. When closed, the upper gate isolates the lower gate from the solids. Because of this shielding action, the sealing surface of the lower gate is not exposed to solids during transit or when it is being lifted or lowered. The chamber containing the lower gate normally is pressurized slightly, and a sweep gas is directed inwardly across the lower-gate sealing surface during the vertical translation of the gate.

  11. The grain-size distribution of pyroclasts: Primary fragmentation, conduit sorting or abrasion?

    Science.gov (United States)

    Kueppers, U.; Schauroth, J.; Taddeucci, J.

    2013-12-01

    of magma fragmentation at or close to the fragmentation level. Given the high abrasiveness of pumice, hemispherical clasts should be observed if clast break-up followed efficient clast abrasion. As a consequence, finer grained pyroclastic fall deposits do not necessarily proof efficient secondary fragmentation in the conduit but may rather reveal the influence of conduit length on 'What size of pyroclasts can be erupted'?

  12. Optimization of Design of Steam Turbine Exhaust Conduits

    Directory of Open Access Journals (Sweden)

    A. S. Goldin

    2014-01-01

    Full Text Available Improving effectiveness turbine was and remains a key issue for today. In order to improve the efficiency of the turbine is necessary to reduce losses in the steam turbine exhaust conduit.This paper presents the design optimization exhaust conduit steam turbine K-27-2.9 produced by JSC «KTW» at the design stage. The aims of optimizing the design were: decreasing hydraulic resistance of the conduit, reduction of non-uniformity of the flow at the outlet of the conduit, equalizing steam flow ahead of the condenser tube bundle.The conduit models were made and flows in it were simulated in environment of the Solid Works and its application COSMOS Flo Works.As the initial conduit model was selected exhaust conduit of turbine PT-25/34-3.4 produced by JSC «KTW». Was obtained by the calculated velocity field at the outlet of the conduit. The analysis of the calculation results revealed the necessity of changes to the initial design of the conduit. The changes were accompanied by calculating currents flow in the conduit, and assessed the impact of design changes on the nature of the course. Further transformation of the construction of the conduit was held on the results of these calculations. Construction changes are not touched by the outer geometry of the conduit, and were introduced to meet technological.According to calculation results, conclusions were drawn and selected three versions of the conduit.Given are the research results for the initial conduit model and modified design versions. In order to evaluate the flow degree of irregularity the momentum factor (Bussinesku factor for outlet crosssection of the selected conduit design version. Analysis of the research results made it possible to determine optimum design of the exhaust conduit.Introducing the suggested alterations in the conduit design will result in improvement of heat exchange in the condenser, an increase in reliability of the tube bundle operation, a decrease in noise and

  13. "Hazelwood v. Kuhlmeier": Closing "Tinker's" Schoolhouse Gate.

    Science.gov (United States)

    Sneed, Maree; Knevila, Kelly

    1988-01-01

    The resolution of free speech issues in the public school context has, until recently, involved a precarious balancing between the First Amendment rights of students and teachers and the role of public schools in inculcating students with fundamental values. This year, in "Hazelwood School District v. Kuhlmeier," the Supreme Court struck…

  14. Ceramic fiber blanket wrap for fire protection of cable trays and conduits

    International Nuclear Information System (INIS)

    Chaille, C.E.; Reiman, R.J.

    1980-01-01

    In some areas of nuclear power plants, cables of redundant electrical systems, which are necessary for the safe shutdown of the reactor, are in close proximity. If a fire should occur in one of these areas, both electrical systems could be destroyed before the fire is extinguished and control of the reactor may be lost. A ceramic fiber blanket was evaluated as a fire protective wrap around cable trays and conduits. 2 refs

  15. SQUG cable tray and conduit evaluation procedure

    International Nuclear Information System (INIS)

    Smith, P.D.; Eder, S.J.; Conoscente, J.P.

    1990-01-01

    Cable tray and conduit systems for electrical cables are a common feature and industrial facilities. They have an excellent performance history in past strong earthquake, even though they are rarely designed for earthquakes. Considerable data have been gathered on their performance in earthquakes and in shake table testing. The data have been used to develop a procedure for the verification of the seismic adequacy of cable tray and conduit systems in operating nuclear plants. The procedure is discussed in this paper. It will result in substantial savings, such as reduced engineering effort, fewer modifications of existing hardware, and simpler documentation, relative to alternate procedures like dynamic analysis of shake table testing. The procedure ensures safety-function in a unique manner since the methodology used to develop it (1) is based on a large body of historical data and (2) uses a relative approach of ensuring that nuclear plant systems will perform at least as well as systems that performed well in past earthquakes. (orig.)

  16. LOAD ON BURIED PRESSURE CONDUITS WITH REFERENCE TO ...

    African Journals Online (AJOL)

    width of conduit or trench; the shearing forces on the plane between the backfill and adjacent earth; for embankment condition, the amounL of relative settlement between the backfill and adjacent earth; the rigidity of the conduit support under embankment loading. Table 3. Selected values of c'' for use in Eq. 8. Sand and.

  17. Water Flow in Karst Aquifer Considering Dynamically Variable Saturation Conduit

    Science.gov (United States)

    Tan, Chaoqun; Hu, Bill X.

    2017-04-01

    The karst system is generally conceptualized as dual-porosity system, which is characterized by low conductivity and high storage continuum matrix and high conductivity and quick flow conduit networks. And so far, a common numerical model for simulating flow in karst aquifer is MODFLOW2005-CFP, which is released by USGS in 2008. However, the steady-state approach for conduit flow in CFP is physically impractical when simulating very dynamic hydraulics with variable saturation conduit. So, we adopt the method proposed by Reimann et al. (2011) to improve current model, in which Saint-Venant equations are used to model the flow in conduit. Considering the actual background that the conduit is very big and varies along flow path and the Dirichlet boundary varies with rainfall in our study area in Southwest China, we further investigate the influence of conduit diameter and outflow boundary on numerical model. And we also analyze the hydraulic process in multi-precipitation events. We find that the numerical model here corresponds well with CFP for saturated conduit, and it could depict the interaction between matrix and conduit during very dynamic hydraulics pretty well compare with CFP.

  18. How to quantify conduits in wood?

    Science.gov (United States)

    Scholz, Alexander; Klepsch, Matthias; Karimi, Zohreh; Jansen, Steven

    2013-01-01

    Vessels and tracheids represent the most important xylem cells with respect to long distance water transport in plants. Wood anatomical studies frequently provide several quantitative details of these cells, such as vessel diameter, vessel density, vessel element length, and tracheid length, while important information on the three dimensional structure of the hydraulic network is not considered. This paper aims to provide an overview of various techniques, although there is no standard protocol to quantify conduits due to high anatomical variation and a wide range of techniques available. Despite recent progress in image analysis programs and automated methods for measuring cell dimensions, density, and spatial distribution, various characters remain time-consuming and tedious. Quantification of vessels and tracheids is not only important to better understand functional adaptations of tracheary elements to environment parameters, but will also be essential for linking wood anatomy with other fields such as wood development, xylem physiology, palaeobotany, and dendrochronology.

  19. Magma wagging and whirling in volcanic conduits

    Science.gov (United States)

    Liao, Yang; Bercovici, David; Jellinek, Mark

    2018-02-01

    Seismic tremor characterized by 0.5-7 Hz ground oscillations commonly occur before and during eruptions at silicic volcanoes with widely ranging vent geometries and edifice structures. The ubiquitous characteristics of this tremor imply that its causes are potentially common to silicic volcanoes. Here we revisit and extend to three dimensions the magma-wagging model for tremor (Jellinek and Bercovici, 2011; Bercovici et al., 2013), wherein a stiff magma column rising in a vertical conduit oscillates against a surrounding foamy annulus of bubbly magma, giving rise to tremor. While prior studies were restricted to two-dimensional lateral oscillations, here we explore three-dimensional motion and additional modes of oscillations. In the absence of viscous damping, the magma column undergoes 'whirling' motion: the center of each horizontal section of the column traces an elliptical trajectory. In the presence of viscous effect we identify new 'coiling' and 'uncoiling' column bending shapes with relatively higher and comparable rates of dissipation to the original two-dimensional magma wagging model. We also calculate the seismic P-wave response of the crustal material around the volcanic conduit to the new whirling motions and propose seismic diagnostics for different wagging patterns using the time-lag between seismic stations. We test our model by analyzing pre-eruptive seismic data from the 2009 eruption of Redoubt Volcano. In addition to suggesting that the occurrence of elliptical whirling motion more than 1 week before the eruption, our analysis of seismic time-lags also implies that the 2009 eruption was accompanied by qualitative changes in the magma wagging behavior including fluctuations in eccentricity and a reversal in the direction of elliptical whirling motion when the eruption was immediately impending.

  20. Precise linear gating circuit on integrated microcircuits

    Energy Technology Data Exchange (ETDEWEB)

    Butskii, V.V.; Vetokhin, S.S.; Reznikov, I.V.

    Precise linear gating circuit on four microcircuits is described. A basic flowsheet of the gating circuit is given. The gating circuit consists of two input differential cascades total load of which is two current followers possessing low input and high output resistances. Follower outlets are connected to high ohmic dynamic load formed with a current source which permits to get high amplification (>1000) at one cascade. Nonlinearity amounts to <0.1% in the range of input signal amplitudes of -10-+10 V. Front duration for an output signal with 10 V amplitude amounts to 100 ns. Attenuation of input signal with a closed gating circuit is 60 db. The gating circuits described is used in the device intended for processing of scintillation sensor signals.

  1. Reverse Saphenous Conduit Flap in 19 Dogs and 1 Cat.

    Science.gov (United States)

    Cavalcanti, Jacqueline V J; Barry, Sabrina L; Lanz, Otto I; Barnes, Katherine; Coutin, Julia V

    2018-05-14

    The purpose of this retrospective study was to report the outcomes of 19 dogs and 1 cat undergoing reverse saphenous conduit flap between 1999 and 2016. Reverse saphenous conduit flap was used to treat traumatic wounds and wounds resulting from tumor excision in the hind limb; the majority of cases had medial shearing injuries. All animals had complete flap survival. In five animals (20%), minor donor site dehiscence occurred, which did not require surgery. Other postoperative complications included signs of severe venous congestion in one dog. Reverse saphenous conduit flap is a useful technique to repair skin defects of the distal hind limb.

  2. New gate opening hours

    CERN Multimedia

    GS Department

    2009-01-01

    Please note the new opening hours of the gates as well as the intersites tunnel from the 19 May 2009: GATE A 7h - 19h GATE B 24h/24 GATE C 7h - 9h\t17h - 19h GATE D 8h - 12h\t13h - 16h GATE E 7h - 9h\t17h - 19h Prévessin 24h/24 The intersites tunnel will be opened from 7h30 to 18h non stop. GS-SEM Group Infrastructure and General Services Department

  3. Biological conduit small gap sleeve bridging method for peripheral nerve injury: regeneration law of nerve fibers in the conduit

    Directory of Open Access Journals (Sweden)

    Pei-xun Zhang

    2015-01-01

    Full Text Available The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair peripheral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good histocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve fibers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2-8 weeks, the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objective and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury.

  4. Gate A: changes to opening hours

    CERN Multimedia

    2015-01-01

    Due to maintenance work, the opening hours of Gate A (near Reception) will be modified between Monday, 13 and Friday, 17 April 2015.   During this period, the gate will be open to vehicles between 7 a.m. and 9.30 a.m., then between 4.30 p.m. and 7 p.m. It will be completely closed to traffic between 9.30 a.m. and 4.30 p.m. Pedestrians and cyclists may continue to use the gate. We apologise for any inconvenience and thank you for your understanding.

  5. 26 CFR 1.7701(l)-1 - Conduit financing arrangements.

    Science.gov (United States)

    2010-04-01

    ... determines that such recharacterization is appropriate to prevent avoidance of any tax imposed by title 26 of...) INCOME TAX (CONTINUED) INCOME TAXES General Actuarial Valuations § 1.7701(l)-1 Conduit financing...

  6. Ileal-conduit following cystectomy, single-institution revision of indications and outcome

    International Nuclear Information System (INIS)

    Abol-Enein, Hassan A.; Abdul-Muhsin, Ausama S.; Alhallaq, Yousuf M.

    2008-01-01

    Objective was to revise indications, case fatality ratio, and postoperative early and late complications of ileal conduit as a method of urinary diversion. This is a retrospective study in which 200 patients underwent an ileal conduit from August 1994 to December 2000 in Mansoura Urology and Nephrology Center, Mansoura, Egypt. Preoperative criteria of patient selection, preoperative findings and postoperative follow-up data were reviewed. In 200 patients aged 29-75 years, with a mean age of 55.84-/+ 8.91 years, the ileal conduit was chosen as a method of urinary diversion, due to one of the following patient or surgical factors; 50 (25%) cardiopulmonary co-morbidities, 27(13.5%) liver cirrhosis, 20 (10%) impaired renal function, 18 (9%) poorly controlled diabetes mellitus and 3 (1.5%) morbid obesity. Frozen section pathological examination showed carcinoma invasion of the urethra in 26 (13%) and prostate stroma in 16 (8%) male patients. Severe adhesions and difficulty cystectomy were encountered in 25 (12.5%) patients. Tumor was found at or close to the bladder neck in 13 (6.5%) female patients and 2 (1%) patients were found to have short mesentery. The mean follow up period was 90.02 -/+ 22.63 months. Fatality rate was 2%. Twenty-three (11.5%) patients had early complications, while 36 (23.7%) patients had late complications. Ileal conduit is still the best urinary diversion method in many patients who have bladder cancer with associated chronic medical disease or certain surgical factors that render other urinary diversion methods more difficult carry more postoperative morbidity and mortality or both. (author)

  7. The cooperative voltage sensor motion that gates a potassium channel.

    Science.gov (United States)

    Pathak, Medha; Kurtz, Lisa; Tombola, Francesco; Isacoff, Ehud

    2005-01-01

    The four arginine-rich S4 helices of a voltage-gated channel move outward through the membrane in response to depolarization, opening and closing gates to generate a transient ionic current. Coupling of voltage sensing to gating was originally thought to operate with the S4s moving independently from an inward/resting to an outward/activated conformation, so that when all four S4s are activated, the gates are driven to open or closed. However, S4 has also been found to influence the cooperative opening step (Smith-Maxwell et al., 1998a), suggesting a more complex mechanism of coupling. Using fluorescence to monitor structural rearrangements in a Shaker channel mutant, the ILT channel (Ledwell and Aldrich, 1999), that energetically isolates the steps of activation from the cooperative opening step, we find that opening is accompanied by a previously unknown and cooperative movement of S4. This gating motion of S4 appears to be coupled to the internal S6 gate and to two forms of slow inactivation. Our results suggest that S4 plays a direct role in gating. While large transmembrane rearrangements of S4 may be required to unlock the gating machinery, as proposed before, it appears to be the gating motion of S4 that drives the gates to open and close.

  8. Artificial urinary conduit construction using tissue engineering methods.

    Science.gov (United States)

    Kloskowski, Tomasz; Pokrywczyńska, Marta; Drewa, Tomasz

    2015-01-01

    Incontinent urinary diversion using an ileal conduit is the most popular method used by urologists after bladder cystectomy resulting from muscle invasive bladder cancer. The use of gastrointestinal tissue is related to a series of complications with the necessity of surgical procedure extension which increases the time of surgery. Regenerative medicine together with tissue engineering techniques gives hope for artificial urinary conduit construction de novo without affecting the ileum. In this review we analyzed history of urinary diversion together with current attempts in urinary conduit construction using tissue engineering methods. Based on literature and our own experience we presented future perspectives related to the artificial urinary conduit construction. A small number of papers in the field of tissue engineered urinary conduit construction indicates that this topic requires more attention. Three main factors can be distinguished to resolve this topic: proper scaffold construction along with proper regeneration of both the urothelium and smooth muscle layers. Artificial urinary conduit has a great chance to become the first commercially available product in urology constructed by regenerative medicine methods.

  9. Double-disc gate valve

    International Nuclear Information System (INIS)

    Wheatley, S.J.

    1979-01-01

    The invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewith, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separation of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve

  10. Gate replacement at the Upper Lake Falls development

    International Nuclear Information System (INIS)

    Chen, C.T.; Locke, A.E.; Brown, E.R.

    1998-01-01

    Nova Scotia Power's integrated approach to dam safety was discussed. One of the two intake gates at Unit 1 of the Upper Falls Power Plant on the Mersey River was replaced in 1997 as part of the Utility's upgrading program. In the event of governor failure or turbine runaway, the new roller gate will allow operators to close the original sliding gate first under a more-or-less balanced head condition, and then to close the new roller gate under a full-flow condition. The planning, design and construction of the new roller gate is described. One of the two head gates of Unit 2 at the same station will be replaced in a similar fashion in the fall of 1998. 4 refs., 7 figs

  11. Incorporation of cooling-induced crystallization into a 2-dimensional axisymmetric conduit heat flow model

    Science.gov (United States)

    Heptinstall, David; Bouvet de Maisonneuve, Caroline; Neuberg, Jurgen; Taisne, Benoit; Collinson, Amy

    2016-04-01

    Heat flow models can bring new insights into the thermal and rheological evolution of volcanic 3 systems. We shall investigate the thermal processes and timescales in a crystallizing, static 4 magma column, with a heat flow model of Soufriere Hills Volcano (SHV), Montserrat. The latent heat of crystallization is initially computed with MELTS, as a function of pressure and temperature for an andesitic melt (SHV groundmass starting composition). Three fractional crystallization simulations are performed; two with initial pressures of 34MPa (runs 1 & 2) and one of 25MPa (run 3). Decompression rate was varied between 0.1MPa/° C (runs 1 & 3) and 0.2MPa/° C (run 2). Natural and experimental matrix glass compositions are accurately reproduced by all MELTS runs. The cumulative latent heat released for runs 1, 2 and 3 differs by less than 9% (8.69E5 J/kg*K, 9.32E5 J/kg*K, and 9.49E5 J/kg*K respectively). The 2D axisymmetric conductive cooling simulations consider a 30m-diameter conduit that extends from the surface to a depth of 1500m (34MPa). The temporal evolution of temperature is closely tracked at depths of 10m, 750m and 1400m in the centre of the conduit, at the conduit walls, and 20m from the walls into the host rock. Following initial cooling by 7-15oC at 10m depth inside the conduit, the magma temperature rebounds through latent heat release by 32-35oC over 85-123 days to a maximum temperature of 1002-1005oC. At 10m depth, it takes 4.1-9.2 years for the magma column to cool by 108-131oC and crystallize to 75wt%, at which point it cannot be easily remobilized. It takes 11-31.5 years to reach the same crystallinity at 750-1400m depth. We find a wide range in cooling timescales, particularly at depths of 750m or greater, attributed to the initial run pressure and the dominant latent heat producing crystallizing phase, Albite-rich Plagioclase Feldspar. Run 1 is shown to cool fastest and run 3 cool the slowest, with surface emissivity having the strongest cooling

  12. In Vitro Study of Directly Bioprinted Perfusable Vasculature Conduits.

    Science.gov (United States)

    Zhang, Yahui; Yu, Yin; Akkouch, Adil; Dababneh, Amer; Dolati, Farzaneh; Ozbolat, Ibrahim T

    2015-01-01

    The ability to create three dimensional (3D) thick tissues is still a major tissue engineering challenge. It requires the development of a suitable vascular supply for an efficient media exchange. An integrated vasculature network is particularly needed when building thick functional tissues and/or organs with high metabolic activities, such as the heart, liver and pancreas. In this work, human umbilical vein smooth muscle cells (HUVSMCs) were encapsulated in sodium alginate and printed in the form of vasculature conduits using a coaxial deposition system. Detailed investigations were performed to understand the dehydration, swelling and degradation characteristics of printed conduits. In addition, because perfusional, permeable and mechanical properties are unique characteristics of natural blood vessels, for printed conduits these properties were also explored in this work. The results show that cells encapsulated in conduits had good proliferation activities and that their viability increased during prolonged in vitro culture. Deposition of smooth muscle matrix and collagen was observed around the peripheral and luminal surface in long-term cultured cellular vascular conduit through histology studies.

  13. Ash production by attrition in volcanic conduits and plumes.

    Science.gov (United States)

    Jones, T J; Russell, J K

    2017-07-17

    Tephra deposits result from explosive volcanic eruption and serve as indirect probes into fragmentation processes operating in subsurface volcanic conduits. Primary magmatic fragmentation creates a population of pyroclasts through volatile-driven decompression during conduit ascent. In this study, we explore the role that secondary fragmentation, specifically attrition, has in transforming primary pyroclasts upon transport in volcanic conduits and plumes. We utilize total grain size distributions from a suite of natural and experimentally produced tephra to show that attrition is likely to occur in all explosive volcanic eruptions. Our experimental results indicate that fine ash production and surface area generation is fast (eruption column stability, tephra dispersal, aggregation, volcanic lightening generation, and has concomitant effects on aviation safety and Earth's climate.

  14. Quantum gate decomposition algorithms.

    Energy Technology Data Exchange (ETDEWEB)

    Slepoy, Alexander

    2006-07-01

    Quantum computing algorithms can be conveniently expressed in a format of a quantum logical circuits. Such circuits consist of sequential coupled operations, termed ''quantum gates'', or quantum analogs of bits called qubits. We review a recently proposed method [1] for constructing general ''quantum gates'' operating on an qubits, as composed of a sequence of generic elementary ''gates''.

  15. Design of barrier coatings on kink-resistant peripheral nerve conduits

    Directory of Open Access Journals (Sweden)

    Basak Acan Clements

    2016-02-01

    Full Text Available Here, we report on the design of braided peripheral nerve conduits with barrier coatings. Braiding of extruded polymer fibers generates nerve conduits with excellent mechanical properties, high flexibility, and significant kink-resistance. However, braiding also results in variable levels of porosity in the conduit wall, which can lead to the infiltration of fibrous tissue into the interior of the conduit. This problem can be controlled by the application of secondary barrier coatings. Using a critical size defect in a rat sciatic nerve model, the importance of controlling the porosity of the nerve conduit walls was explored. Braided conduits without barrier coatings allowed cellular infiltration that limited nerve recovery. Several types of secondary barrier coatings were tested in animal studies, including (1 electrospinning a layer of polymer fibers onto the surface of the conduit and (2 coating the conduit with a cross-linked hyaluronic acid-based hydrogel. Sixteen weeks after implantation, hyaluronic acid-coated conduits had higher axonal density, displayed higher muscle weight, and better electrophysiological signal recovery than uncoated conduits or conduits having an electrospun layer of polymer fibers. This study indicates that braiding is a promising method of fabrication to improve the mechanical properties of peripheral nerve conduits and demonstrates the need to control the porosity of the conduit wall to optimize functional nerve recovery.

  16. Free-boundary models of a meltwater conduit

    KAUST Repository

    Dallaston, Michael C.; Hewitt, Ian J.

    2014-01-01

    © 2014 AIP Publishing LLC. We analyse the cross-sectional evolution of an englacial meltwater conduit that contracts due to inward creep of the surrounding ice and expands due to melting. Making use of theoretical methods from free-boundary problems

  17. Hydraulic analysis of harmonic pumping tests in frequency and time domains for identifying the conduits networks in a karstic aquifer

    Science.gov (United States)

    Fischer, P.; Jardani, A.; Cardiff, M.; Lecoq, N.; Jourde, H.

    2018-04-01

    In a karstic field, the flow paths are very complex as they globally follow the conduit network. The responses generated from an investigation in this type of aquifer can be spatially highly variable. Therefore, the aim of the investigation in this case is to define a degree of connectivity between points of the field, in order to understand these flow paths. Harmonic pumping tests represent a possible investigation method for characterizing the subsurface flow of groundwater. They have several advantages compared to a constant-rate pumping (more signal possibilities, ease of extracting the signal in the responses and possibility of closed loop investigation). We show in this work that interpreting the responses from a harmonic pumping test is very useful for delineating a degree of connectivity between measurement points. We have firstly studied the amplitude and phase offset of responses from a harmonic pumping test in a theoretical synthetic modeling case in order to define a qualitative interpretation method in the time and frequency domains. Three different type of responses have been separated: a conduit connectivity response, a matrix connectivity, and a dual connectivity (response of a point in the matrix, but close to a conduit). We have then applied this method to measured responses at a field research site. Our interpretation method permits a quick and easy reconstruction of the main flow paths, and the whole set of field responses appear to give a similar range of responses to those seen in the theoretical synthetic case.

  18. Development of a comprehensive inventory management system for underground fiber optic conduits.

    Science.gov (United States)

    2013-03-01

    Major State Departments of Transportation operate and maintain networks of thousands of miles of conduits, many : carrying fiber optic cables that are vital to State communication systems. These conduits are located alongside or : across highways and...

  19. Incorporation of cooling-induced crystallisation into a 2-dimensional axisymmetric conduit heat flow model

    Science.gov (United States)

    Heptinstall, D. A.; Neuberg, J. W.; Bouvet de Maisonneuve, C.; Collinson, A.; Taisne, B.; Morgan, D. J.

    2015-12-01

    Heat flow models can bring new insights into the thermal and rheological evolution of volcanic systems. We shall investigate the thermal processes and timescales in a crystallizing, static magma column, with a heat flow model of Soufriere Hills Volcano (SHV), Montserrat. The latent heat of crystallization is initially computed with MELTS, as a function of pressure and temperature for an andesitic melt (SHV groundmass starting composition). Three fractional crystallization simulations are performed; two with initial pressures of 34MPa (runs 1 & 2) and one of 25MPa (run 3). Decompression rate was varied between 0.1MPa/°C (runs 1 & 3) and 0.2MPa/°C (run 2). Natural and experimental matrix glass compositions are accurately reproduced by all MELTS runs. The cumulative latent heat released for runs 1, 2 and 3 differs by less than 9% (8.69e5 J/kg*K, 9.32e5 J/kg*K, and 9.49e5 J/kg*K respectively). The 2D axisymmetric conductive cooling simulations consider a 30m-diameter conduit that extends from the surface to a depth of 1500m (34MPa). The temporal evolution of temperature is closely tracked at depths of 10m, 750m and 1400m in the center of the conduit, at the conduit walls, and 20m from the walls into the host rock. Following initial cooling by 7-15oC at 10m depth inside the conduit, the magma temperature rebounds through latent heat release by 32-35oC over 85-123 days to a maximum temperature of 1002-1005oC. At 10 m depth, it takes 4.1-9.2 years for the magma column to cool over 108-130oC and crystallize to 75wt%, at which point it cannot be easily remobilized. It takes 11-31.5 years to reach the same crystallinity at 750-1400m depth. We find a wide range in cooling timescales, particularly at depths of 750m or greater, attributed to the initial run pressure and dominant latent heat producing crystallizing phases (Quartz), where run 1 cools fastest and run 3 cools slowest. Surface cooling by comparison has the strongest influence on the upper tens of meters in all

  20. POROSITY OF THE WALL OF A NEUROLAC (R) NERVE CONDUIT HAMPERS NERVE REGENERATION

    NARCIS (Netherlands)

    Meek, Marcel F.; Den Dunnen, Wilfred F. A.

    2009-01-01

    One way to improve nerve regeneration and bridge longer nerve gaps may be the use of semipermeable/porous conduits. With porosity less biomaterial is used for the nerve conduit. We evaluated the short-term effects of porous Neurolac (R) nerve conduits for in vivo peripheral nerve regeneration. In 10

  1. SU-E-T-350: Verification of Gating Performance of a New Elekta Gating Solution: Response Kit and Catalyst System

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X; Cao, D; Housley, D; Mehta, V; Shepard, D [Swedish Cancer Institute, Seattle, WA (United States)

    2014-06-01

    Purpose: In this work, we have tested the performance of new respiratory gating solutions for Elekta linacs. These solutions include the Response gating and the C-RAD Catalyst surface mapping system.Verification measurements have been performed for a series of clinical cases. We also examined the beam on latency of the system and its impact on delivery efficiency. Methods: To verify the benefits of tighter gating windows, a Quasar Respiratory Motion Platform was used. Its vertical-motion plate acted as a respiration surrogate and was tracked by the Catalyst system to generate gating signals. A MatriXX ion-chamber array was mounted on its longitudinal-moving platform. Clinical plans are delivered to a stationary and moving Matrix array at 100%, 50% and 30% gating windows and gamma scores were calculated comparing moving delivery results to the stationary result. It is important to note that as one moves to tighter gating windows, the delivery efficiency will be impacted by the linac's beam-on latency. Using a specialized software package, we generated beam-on signals of lengths of 1000ms, 600ms, 450ms, 400ms, 350ms and 300ms. As the gating windows get tighter, one can expect to reach a point where the dose rate will fall to nearly zero, indicating that the gating window is close to beam-on latency. A clinically useful gating window needs to be significantly longer than the latency for the linac. Results: As expected, the use of tighter gating windows improved delivery accuracy. However, a lower limit of the gating window, largely defined by linac beam-on latency, exists at around 300ms. Conclusion: The Response gating kit, combined with the C-RAD Catalyst, provides an effective solution for respiratorygated treatment delivery. Careful patient selection, gating window design, even visual/audio coaching may be necessary to ensure both delivery quality and efficiency. This research project is funded by Elekta.

  2. Optical XOR gate

    Science.gov (United States)

    Vawter, G. Allen

    2013-11-12

    An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  3. Frictional melting and stick-slip behavior in volcanic conduits

    Science.gov (United States)

    Kendrick, Jackie Evan; Lavallee, Yan; Hirose, Takehiro; di Toro, Giulio; Hornby, Adrian Jakob; Hess, Kai-Uwe; Dingwell, Donald Bruce

    2013-04-01

    Dome-building eruptions have catastrophic potential, with dome collapse leading to devastating pyroclastic flows with almost no precursory warning. During dome growth, the driving forces of the buoyant magma may be superseded by controls along conduit margins; where brittle fracture and sliding can lead to formation of lubricating cataclasite and gouge. Under extreme friction, pseudotachylyte may form at the conduit margin. Understanding the conduit margin processes is vital to understanding the continuation of an eruption and we postulate that pseudotachylyte generation could be the underlying cause of stick-slip motion and associated seismic "drumbeats", which are so commonly observed at dome-building volcanoes. This view is supported by field evidence in the form of pseudotachylytes identified in lava dome products at Soufrière Hills (Montserrat) and Mount St. Helens (USA). Both eruptions were characterised by repetitive, periodic seismicity and lava spine extrusion of highly viscous magma. High velocity rotary shear (HVR) experiments demonstrate the propensity for melting of the andesitic and dacitic material (from Soufrière Hills and Mount St. Helens respectively) at upper conduit stress conditions (HVR experiments which mimic rapid velocity fluctuations in stick-slip behavior demonstrate velocity-weakening behavior of melt, with a tendency for unstable slip. During ascent, magma may slip and undergo melting along the conduit margin. In the process the shear resistance of the slip zone is increased, acting as a viscous brake halting slip (the "stick" of stick-slip motion). Sufficient buoyancy-driven pressures from ascending magma below eventually overcome resistance to produce a rapid slip event (the "slip") along the melt-bearing slip zone, which is temporarily lubricated due to velocity-weakening. New magma below experiences the same slip event more slowly (as the magma decompresses) to produce a viscous brake and the process is repeated. This allows a

  4. Biocarbon urinary conduit: laboratory experience and clinical applications.

    Science.gov (United States)

    Kobashi, L I; Raible, D A

    1980-07-01

    A new urinary conduit utilizing pure vitreous carbon has been used successfully in dogs. Pure carbon appears to be inert with respect to urine and urothelium. Lack of urinary salt encrustation on the exposed surface provides a well-functioning urinary conduit for vesical drainage. Twenty-one vesicostomies were performed in dogs. Careful follow-up and histologic studies of removed specimens were done to establish the biocompatibility of pure carbon. All vesicostomies functioned well. A description of the device, protocol, and results of laboratory experimentation are outlined. The surgical procedure is explained in detail. Results encourage the clinical trial of these devices in humans. Indications include patients with neurogenic vesicla dysfunction and those with total urinary incontinence, both of which require permanent indwelling catheters.

  5. Tension layer winding of cable-in-conduit conductor

    International Nuclear Information System (INIS)

    Devernoe, A.; Ciancetta, G.; King, M.; Parizh, M.; Painter, T.; Miller, J.

    1996-01-01

    A 710 mm i.d. by 440 mm long, 6 layer Cable-in-Conduit (CIC) coil was precision tension layer wound with Incoloy 908 jacketed conductor to model winding technology that will be used for the Nb 3 Sn outsert coils of the 45 Tesla Hybrid Magnet Project at the US National High Magnetic Field Laboratory. This paper reports on the set up of a new winding facility with unique capabilities for insulating and winding long length CIC conductor and on special procedures which were developed to wind and support layer to layer transitions and to safely form conductor into and out of the winding. Analytical methods used to predict conduit keystoning, springback and back tensioning requirements before winding are reported in comparison to results obtained during winding and actual winding build-up dimensions on a layer by layer basis in comparison to design requirements

  6. Erosion of cohesive soil layers above underground conduits

    Directory of Open Access Journals (Sweden)

    Luu Li-Hua

    2017-01-01

    Full Text Available Using a recently developed 2D numerical modelling that combines Discrete Element (DEM and Lattice Boltzmann methods (LBM, we simulate the destabilisation by an hydraulic gradient of a cohesive granular soil clogging the top of an underground conduit. We aim to perform a multi-scale study that relates the grain scale behavior to the macroscopic erosion process. In particular, we study the influence of the flow conditions and the inter-particle contact forces intensity on the erosion kinetic.

  7. Erosion of cohesive soil layers above underground conduits

    Science.gov (United States)

    Luu, Li-Hua; Philippe, Pierre; Noury, Gildas; Perrin, Jérôme; Brivois, Olivier

    2017-06-01

    Using a recently developed 2D numerical modelling that combines Discrete Element (DEM) and Lattice Boltzmann methods (LBM), we simulate the destabilisation by an hydraulic gradient of a cohesive granular soil clogging the top of an underground conduit. We aim to perform a multi-scale study that relates the grain scale behavior to the macroscopic erosion process. In particular, we study the influence of the flow conditions and the inter-particle contact forces intensity on the erosion kinetic.

  8. CIBLAGE D'INFLATION ET CONDUITE DE LA POLITIQUE ...

    African Journals Online (AJOL)

    Administrateur

    de l'amendement de la loi relative à la monnaie et au crédit, l'Algérie a explicitement ... la Banque d'Algérie, très importante pour la conduite de la politique monétaire. ..... matière de contrainte budgétaire entre les secteurs public et privé. En.

  9. Explosive device of conduit using Ti Ni alloy

    Directory of Open Access Journals (Sweden)

    A. Yu. Kolobov

    2014-01-01

    Full Text Available Presently, materials have been developed which are capable at changing temperate to return significant inelastic deformations, exhibit rubber-like elasticity, convert heat into mechanical work, etc. The aggregate of these effects is usually called the shape memory effect.At present a great number of compounds and alloys with a shape memory effect has been known.These are alloys based on titanium nickelide (TiNi, copper-based alloys (Cu-Al, Cu-Sn, Cu-Al-Ni, Cu-Zn-Si, etc., gold and silver (Ag-Cd, Au-Ag-Cd, Au-Cd-Cu, Au-Zn-Cu, etc., manganese (Mn-Cr, Fe-Cu, Mn-Cu-Ni, Mn-Cu-Zr, Mn-Ni, etc., iron (Fe-Mn, Fe-Ni, Fe-Al, etc., and other compounds.The alloys based on titanium nickelide (nitinol are the most widely used.Alloys with shape memory effect find various applications in engineering and medicine, namely connecting devices, actuators, transformable design, multipurpose medical implants, etc.There is a task of breaking fuel conduit during separating the spacecraft from the rocket in space technology.The paper examines the procedure for design calculation of the separating device of conduit with the use of Ti-Ni alloy. This device can be used instead of the pyro-knives.The device contains two semi-rings from Ti-Ni alloy. In the place of break on the conduit an annular radius groove is made.At a temperature of martensite passage the semi-rings undergo deformation and in the strained state are set in the device. With heating to the temperature of the austenitic passage of bushing macro-deformation the energy stored by the nitinol bushing is great enough to break the conduit on the neck.The procedures of design calculation and response time of device are given.

  10. Novel drug delivering conduit for peripheral nerve regeneration

    Science.gov (United States)

    Labroo, Pratima; Shea, Jill; Edwards, Kyle; Ho, Scott; Davis, Brett; Sant, Himanshu; Goodwin, Isak; Gale, Bruce; Agarwal, Jay

    2017-12-01

    Objective. This paper describes the design of a novel drug delivery apparatus integrated with a poly lactic-co-glycolic acid (PLGA) based nerve guide conduit for controlled local delivery of nerve growth factor (NGF) and application in peripheral nerve gap injury. Approach. An NGF dosage curve was acquired to determine the minimum in vitro concentration for optimal neurite outgrowth of dorsal root ganglion (DRG) cells; PLGA based drug delivery devices were then designed and tested in vitro and in vivo across 15 mm rat sciatic nerve gap injury model. Main results. The drug delivery nerve guide was able to release NGF for 28 d at concentrations (0.1-10 ng ml-1) that were shown to enhance DRG neurite growth. Furthermore, the released NGF was bioactive and able to enhance DRG neurite growth. Following these tests, optimized NGF-releasing nerve conduits were implanted across 15 mm sciatic nerve gaps in a rat model, where they demonstrated significant myelination and muscle innervation in vivo as compared to empty nerve conduits (p  design process and provides increased versatility for releasing a variety of different growth factors. This innovative device has the potential for broad applicability and allows for easier customization to change the type of drugs and dosage of individual drugs without devising a completely new biomaterial-drug conjugate each time.

  11. Free-boundary models of a meltwater conduit

    KAUST Repository

    Dallaston, Michael C.

    2014-08-01

    © 2014 AIP Publishing LLC. We analyse the cross-sectional evolution of an englacial meltwater conduit that contracts due to inward creep of the surrounding ice and expands due to melting. Making use of theoretical methods from free-boundary problems in Stokes flow and Hele-Shaw squeeze flow we construct an exact solution to the coupled problem of external viscous creep and internal heating, in which we adopt a Newtonian approximation for ice flow and an idealized uniform heat source in the conduit. This problem provides an interesting variant on standard free-boundary problems, coupling different internal and external problems through the kinematic condition at the interface. The boundary in the exact solution takes the form of an ellipse that may contract or expand (depending on the magnitudes of effective pressure and heating rate) around fixed focal points. Linear stability analysis reveals that without the melting this solution is unstable to perturbations in the shape. Melting can stabilize the interface unless the aspect ratio is too small; in that case, instabilities grow largest at the thin ends of the ellipse. The predictions are corroborated with numerical solutions using boundary integral techniques. Finally, a number of extensions to the idealized model are considered, showing that a contracting circular conduit is unstable to all modes of perturbation if melting occurs at a uniform rate around the boundary, or if the ice is modelled as a shear-thinning fluid.

  12. Mechanical cleaning of oil spills in seawater using circular conduits

    Energy Technology Data Exchange (ETDEWEB)

    Shedid, S.; Abou Kassem, J.; Zekri, A. [United Arab Emirates Univ., Al Ain City (United Arab Emirates). Dept. of Chemical and Petroleum Engineering

    2005-10-15

    Treatment of the crude oil pollution in seawater has attracted global attention during the last two decades. This study was undertaken using circular conduits as a mechanical means to clean oil spills in seawater under different conditions of temperature, oil gravity, shaking frequency, conduit diameter, and initial thickness of oil layer. An experimental model was designed and built to achieve the study. It consists of shaking water bath (to represent sea waves) fitted with temperature controller and glass tubes of different inside diameters of 0.3 cm, 0.5 cm, and 0.7 cm. Three crude oils of different oil gravity of 35{sup o}API, 38{sup o}API, and 47{sup o}API were investigated under different shaking frequencies of 20, 40, and 60 stroke/minute with different tube diameters. The results proved that application of mechanical cleaning of oil spills using circular conduits is a practical technique. The cleaning of black oil spills is more efficient than one of volatile oil. Furthermore, the results indicated that the increase of shaking frequency and/or water temperature provide(s) faster cleaning of oil spills while temperature increase recovers the maximum oil. (Author)

  13. Peripheral nerve regeneration with conduits: use of vein tubes.

    Science.gov (United States)

    Sabongi, Rodrigo Guerra; Fernandes, Marcela; Dos Santos, João Baptista Gomes

    2015-04-01

    Treatment of peripheral nerve injuries remains a challenge to modern medicine due to the complexity of the neurobiological nerve regenerating process. There is a greater challenge when the transected nerve ends are not amenable to primary end-to-end tensionless neurorraphy. When facing a segmental nerve defect, great effort has been made to develop an alternative to the autologous nerve graft in order to circumvent morbidity at donor site, such as neuroma formation, scarring and permanent loss of function. Tubolization techniques have been developed to bridge nerve gaps and have been extensively studied in numerous experimental and clinical trials. The use of a conduit intends to act as a vehicle for moderation and modulation of the cellular and molecular ambience for nerve regeneration. Among several conduits, vein tubes were validated for clinical application with improving outcomes over the years. This article aims to address the investigation and treatment of segmental nerve injury and draw the current panorama on the use of vein tubes as an autogenous nerve conduit.

  14. Peripheral nerve regeneration with conduits: use of vein tubes

    Directory of Open Access Journals (Sweden)

    Rodrigo Guerra Sabongi

    2015-01-01

    Full Text Available Treatment of peripheral nerve injuries remains a challenge to modern medicine due to the complexity of the neurobiological nerve regenerating process. There is a greater challenge when the transected nerve ends are not amenable to primary end-to-end tensionless neurorraphy. When facing a segmental nerve defect, great effort has been made to develop an alternative to the autologous nerve graft in order to circumvent morbidity at donor site, such as neuroma formation, scarring and permanent loss of function. Tubolization techniques have been developed to bridge nerve gaps and have been extensively studied in numerous experimental and clinical trials. The use of a conduit intends to act as a vehicle for moderation and modulation of the cellular and molecular ambience for nerve regeneration. Among several conduits, vein tubes were validated for clinical application with improving outcomes over the years. This article aims to address the investigation and treatment of segmental nerve injury and draw the current panorama on the use of vein tubes as an autogenous nerve conduit.

  15. Parastomal hernias after radical cystectomy and ileal conduit diversion

    Directory of Open Access Journals (Sweden)

    Timothy F. Donahue

    2016-07-01

    Full Text Available Parastomal hernia, defined as an “incisional hernia related to an abdominal wall stoma”, is a frequent complication after conduit urinary diversion that can negatively impact quality of life and present a clinically significant problem for many patients. Parastomal hernia (PH rates may be as high as 65% and while many patients are asymptomatic, in some series up to 30% of patients require surgical intervention due to pain, leakage, ostomy appliance problems, urinary obstruction, and rarely bowel obstruction or strangulation. Local tissue repair, stoma relocation, and mesh repairs have been performed to correct PH, however, long-term results have been disappointing with recurrence rates of 30%–76% reported after these techniques. Due to high recurrence rates and the potential morbidity of PH repair, efforts have been made to prevent PH development at the time of the initial surgery. Randomized trials of circumstomal prophylactic mesh placement at the time of colostomy and ileostomy stoma formation have shown significant reductions in PH rates with acceptably low complication profiles. We have placed prophylactic mesh at the time of ileal conduit creation in patients at high risk for PH development and found it to be safe and effective in reducing the PH rates over the short-term. In this review, we describe the clinical and radiographic definitions of PH, the clinical impact and risk factors associated with its development, and the use of prophylactic mesh placement for patients undergoing ileal conduit urinary diversion with the intent of reducing PH rates.

  16. Mechanosensitive gating of Kv channels.

    Directory of Open Access Journals (Sweden)

    Catherine E Morris

    Full Text Available K-selective voltage-gated channels (Kv are multi-conformation bilayer-embedded proteins whose mechanosensitive (MS Popen(V implies that at least one conformational transition requires the restructuring of the channel-bilayer interface. Unlike Morris and colleagues, who attributed MS-Kv responses to a cooperative V-dependent closed-closed expansion↔compaction transition near the open state, Mackinnon and colleagues invoke expansion during a V-independent closed↔open transition. With increasing membrane tension, they suggest, the closed↔open equilibrium constant, L, can increase >100-fold, thereby taking steady-state Popen from 0→1; "exquisite sensitivity to small…mechanical perturbations", they state, makes a Kv "as much a mechanosensitive…as…a voltage-dependent channel". Devised to explain successive gK(V curves in excised patches where tension spontaneously increased until lysis, their L-based model falters in part because of an overlooked IK feature; with recovery from slow inactivation factored in, their g(V datasets are fully explained by the earlier model (a MS V-dependent closed-closed transition, invariant L≥4. An L-based MS-Kv predicts neither known Kv time courses nor the distinctive MS responses of Kv-ILT. It predicts Kv densities (hence gating charge per V-sensor several-fold different from established values. If opening depended on elevated tension (L-based model, standard gK(V operation would be compromised by animal cells' membrane flaccidity. A MS V-dependent transition is, by contrast, unproblematic on all counts. Since these issues bear directly on recent findings that mechanically-modulated Kv channels subtly tune pain-related excitability in peripheral mechanoreceptor neurons we undertook excitability modeling (evoked action potentials. Kvs with MS V-dependent closed-closed transitions produce nuanced mechanically-modulated excitability whereas an L-based MS-Kv yields extreme, possibly excessive

  17. Possibilities Of Opening Up the Stage-Gate Model

    Directory of Open Access Journals (Sweden)

    Biljana Stošić

    2014-12-01

    Full Text Available The paper presents basic elements of the Stage-Gate and Open innovation models, and possible connection of these two, resulting in what is frequently called an “Open Stage-Gate” model. This connection is based on opening up the new product development process and integration of the open innovation principles with the Stage-Gate concept, facilitating the import and export of information and technologies. Having in mind that the Stage Gate has originally been classified as the third generation model of innovation, the paper is dealing with the capabilities for applying the sixth generation Open innovation principles in today’s improved and much more flexible phases and gates of the Stage Gate. Lots of innovative companies are actually using both models in their NPD practice, looking for the most appropriate means of opening up the well-known closed innovation, especially in the domain of ideation through co-creation.

  18. Bubble gate for in-plane flow control.

    Science.gov (United States)

    Oskooei, Ali; Abolhasani, Milad; Günther, Axel

    2013-07-07

    We introduce a miniature gate valve as a readily implementable strategy for actively controlling the flow of liquids on-chip, within a footprint of less than one square millimetre. Bubble gates provide for simple, consistent and scalable control of liquid flow in microchannel networks, are compatible with different bulk microfabrication processes and substrate materials, and require neither electrodes nor moving parts. A bubble gate consists of two microchannel sections: a liquid-filled channel and a gas channel that intercepts the liquid channel to form a T-junction. The open or closed state of a bubble gate is determined by selecting between two distinct gas pressure levels: the lower level corresponds to the "open" state while the higher level corresponds to the "closed" state. During closure, a gas bubble penetrates from the gas channel into the liquid, flanked by a column of equidistantly spaced micropillars on each side, until the flow of liquid is completely obstructed. We fabricated bubble gates using single-layer soft lithographic and bulk silicon micromachining procedures and evaluated their performance with a combination of theory and experimentation. We assessed the dynamic behaviour during more than 300 open-and-close cycles and report the operating pressure envelope for different bubble gate configurations and for the working fluids: de-ionized water, ethanol and a biological buffer. We obtained excellent agreement between the experimentally determined bubble gate operational envelope and a theoretical prediction based on static wetting behaviour. We report case studies that serve to illustrate the utility of bubble gates for liquid sampling in single and multi-layer microfluidic devices. Scalability of our strategy was demonstrated by simultaneously addressing 128 bubble gates.

  19. Amplifying genetic logic gates.

    Science.gov (United States)

    Bonnet, Jerome; Yin, Peter; Ortiz, Monica E; Subsoontorn, Pakpoom; Endy, Drew

    2013-05-03

    Organisms must process information encoded via developmental and environmental signals to survive and reproduce. Researchers have also engineered synthetic genetic logic to realize simpler, independent control of biological processes. We developed a three-terminal device architecture, termed the transcriptor, that uses bacteriophage serine integrases to control the flow of RNA polymerase along DNA. Integrase-mediated inversion or deletion of DNA encoding transcription terminators or a promoter modulates transcription rates. We realized permanent amplifying AND, NAND, OR, XOR, NOR, and XNOR gates actuated across common control signal ranges and sequential logic supporting autonomous cell-cell communication of DNA encoding distinct logic-gate states. The single-layer digital logic architecture developed here enables engineering of amplifying logic gates to control transcription rates within and across diverse organisms.

  20. Cardiac gated ventilation

    International Nuclear Information System (INIS)

    Hanson, C.W. III; Hoffman, E.A.

    1995-01-01

    There are several theoretic advantages to synchronizing positive pressure breaths with the cardiac cycle, including the potential for improving distribution of pulmonary and myocardial blood flow and enhancing cardiac output. The authors evaluated the effects of synchronizing respiration to the cardiac cycle using a programmable ventilator and electron beam CT (EBCT) scanning. The hearts of anesthetized dogs were imaged during cardiac gated respiration with a 50 msec scan aperture. Multi slice, short axis, dynamic image data sets spanning the apex to base of the left ventricle were evaluated to determine the volume of the left ventricular chamber at end-diastole and end-systole during apnea, systolic and diastolic cardiac gating. The authors observed an increase in cardiac output of up to 30% with inspiration gated to the systolic phase of the cardiac cycle in a non-failing model of the heart

  1. Optimization of spent fuel pool weir gate driving mechanism

    Science.gov (United States)

    Liu, Chao; Du, Lin; Tao, Xinlei; Wang, Shijie; Shang, Ertao; Yu, Jianjiang

    2018-04-01

    Spent fuel pool is crucial facility for fuel storage and nuclear safety, and the spent fuel pool weir gate is the key related equipment. In order to achieve a goal of more efficient driving force transfer, loading during the opening/closing process is analyzed and an optimized calculation method for dimensions of driving mechanism is proposed. The result of optimizing example shows that the method can be applied to weir gates' design with similar driving mechanism.

  2. Pseudotachylyte formation in volcanic conduits: Montserrat vs. Mount St. Helens

    Science.gov (United States)

    Kendrick, J. E.; Lavallee, Y.; Petrakova, L.; Ferk, A.; Di Toro, G.; Hess, K.; Ferri, F.; Dingwell, D. B.

    2012-12-01

    Seismogenic fracture and faulting may result in non-equilibrium frictional melting of rock, which upon cooling and recrystallisation forms pseudotachylyte. In volcanic environments, the transition from endogenous to exogenous growth can be attributed to a shift in magma rheology into the brittle regime, and thus the ascent of high-viscosity magma can form discrete shear zones, comparable to tectonic faults, along conduit margins. Pseudotachylytes have, until now, rarely been noted in exogenous volcanic materials and seldom in active volcanic environments. This is despite the simultaneous occurrence of high pressures and differential stresses, which make high-viscosity magmas ideal candidates for the occurrence of frictional melting. Here, we compare the chemical, thermal, magnetic and structural properties of two candidate volcanic pseudotachylytes; one from Soufriere Hills (Montserrat) and one from Mount St. Helens (USA). Additionally, we present data from a set of high-velocity rotary shear experiments on the host materials of these natural pseudotachylytes in which melting was induced after just 10's of centimeters of slip at realistic extrusion velocities (0.4 - 1.6 ms-1) and low normal stresses (0.5-2 MPa). After 1-2 meters of slip a continuous melt layer formed, at which point friction decreased and the fault zone displayed slip-weakening behaviour. For volcanic conduits, this would facilitate temporarily elevated slip rates, or an increase in extrusion rate, and could cause transitions in dome morphology and eruption style. This study demonstrates that shear fracturing in magma or sliding along conduit margins can readily result in frictional melting. The conspicuous absence of pseudotachylytes in active volcanic environments is likely the result of exceptionally high background temperatures which precipitate near-equilibrium melting, thereby obviating one of the characteristic signatures of pseudotachylyte - glassy protomelts formed by selective melting of

  3. Opening of the New Gate E - Final Closure of Gate C - New azur «B» type cern access card

    CERN Multimedia

    Relations with the Host States Service

    2004-01-01

    Gate E ("Charles de Gaulle Gate") to the Meyrin Site will be open, for those entitled to use it, from 1 November 2004. The opening of this Gate should contribute to relieving congestion not only on the Prévessin - RN84 and Meyrin Route border crossings but also at Gates A and B. As a result, Gate C will be closed indefinitely from 1 November 2004. Providing a direct link between the Meyrin Site and the French territory beyond the fenced part of the CERN site, Gate E is the subject of international agreements between CERN, Switzerland and France, on the basis of which the Director-General has issued the "Rules for the Use of Gate E", (document CERN/DSU-RH/12222 of 27 October 2004; see also the latest news in "publications" at http://www.cern.ch/relations/). The main provisions of these Rules are as follows: Gate E is open from Monday to Friday, except on official CERN holidays, from 7.30 a.m. to 9.30 a.m. for access into the site, and from 4.30 p.m. to 6.30 p.m. for passage out of the site. Persons are aut...

  4. Geometry and Hydraulics of Englacial Conduits, Storglaciaren, Sweden

    Science.gov (United States)

    Fountain, A. G.; Schlichting, R.; Frodin, S.; Jacobel, R. W.

    2001-12-01

    Englacial conduits are the primary structure responsible for transporting surface water to the base of a glacier, where it supplies the subglacial hydraulic system and, in turn, affects glacier movement. Despite the well-known theoretical descriptions of englacial conduits, little direct evidence exists about their geometry and hydraulics. In July 2001, we initiated a field effort on Storglaciären, Sweden, to intersect englacial conduits by drilling into the glacier using a hot water drill. A companion project (Jacobel et al., this session) attempted to detect the englacial conduits using ground-penetrating radar. In a typical borehole, the water level remained at the surface while drilling through the impermeable ice. Once a connection was made, the water level dropped roughly 10 m and remained low despite continued water pumping. A small video camera was lowered, with attachments, to measure the geometry of the opening, and water flow speed. The water level in the hole provided a piezometric measure of the pressure. We drilled 22 holes at 3 separate locations and 17 (77%) connected englacially, the remaining 5 reached the bed without englacial connection, of which 2 drained at the bed. The geometry of the connections was highly irregular in cross-section with 1-2 cm openings, reminiscent of crevasse-like features rather than circular cross-sections as anticipated from the theoretical literature. Flow behavior was observed by tracking particle motion. The flow was complicated, in part by the inferred tangential intersection between the borehole and structure, and by the observed surging behavior. Flow speeds were low, on the order of 1 cm sec-1. Water level records from 3 different holes over several days exhibited highly correlated variations and large diurnal excursions. In contrast, records from holes drilled to the bed showed little variation. Based on these measurements, our conceptual picture of the englacial system is that of a sluggish flow system

  5. Short-term outcomes after incontinent conduit for gynecologic cancer: comparison of ileal, sigmoid, and transverse colon.

    Science.gov (United States)

    Tabbaa, Zaid M; Janco, Jo Marie T; Mariani, Andrea; Dowdy, Sean C; McGree, Michaela E; Weaver, Amy L; Cliby, William A

    2014-06-01

    The aim of this study is to estimate the overall rates of significant incontinent conduit-related complications and compare rates between conduit types. This was a retrospective review of 166 patients who underwent incontinent urinary diversion from April 1993 through April 2013. Patients were categorized by conduit type-ileal, sigmoid colon, and transverse colon. Significant conduit-related complications were assessed at 30 and 90days after surgery. Significant conduit-related complication was defined as any of the following: ureteral stricture, conduit leak, conduit obstruction, conduit ischemia, ureteral anastomotic leak, stent obstruction requiring intervention via interventional radiology procedure or reoperation, and renal failure. A total of 166 patients underwent formation of an incontinent urinary conduit, most commonly during exenteration for gynecologic malignancy. There were 129 ileal, 11 transverse colon, and 26 sigmoid conduits. The overall significant conduit-related complication rate within 30days was 15.1%. Complication rates for ileal, transverse and sigmoid conduits were 14.7%, 0%, and 23.1%, respectively (Fisher's exact test, p=0.24). By 90days, the Kaplan-Meier estimated rates of significant complications were 21.8% overall, and 22.3%, 0%, and 28.9%, respectively, by conduit type (log-rank test, p=0.19). The most common significant conduit-related complications were conduit or ureteral anastomotic leaks and conduit obstructions. By 1 and 2years following surgery, the Kaplan-Meier estimated overall rate of significant conduit-related complication increased to 26.5% and 30.1%, respectively. Our study suggests that there are multiple appropriate tissue sites for use in incontinent conduit formation, and surgical approach should be individualized. Most significant conduit-related complications occur within 90days after surgery. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Treatment of right ventricle to pulmonary artery conduit stenosis in infants with hypoplastic left heart syndrome.

    Science.gov (United States)

    Münsterer, Andrea; Kasnar-Samprec, Jelena; Hörer, Jürgen; Cleuziou, Julie; Eicken, Andreas; Malcic, Ivan; Lange, Rüdiger; Schreiber, Christian

    2013-09-01

    To determine the incidence of right ventricle-to-pulmonary artery (RV-PA) conduit stenosis after the Norwood I operation in patients with hypoplastic left heart syndrome (HLHS), and to determine whether the treatment strategy of RV-PA conduit stenosis has an influence on interstage and overall survival. Ninety-six patients had a Norwood operation with RV-PA conduit between 2002 and 2011. Details of reoperations/interventions due to conduit obstruction prior to bidirectional superior cavopulmonary anastomosis (BSCPA) were collected. Overall pre-BSCPA mortality was 17%, early mortality after Norwood, 6%. Early angiography was performed in 34 patients due to desaturation at a median of 8 days after the Norwood operation. Fifteen patients (16%) were diagnosed with RV-PA conduit stenosis that required treatment. The location of the conduit stenosis was significantly different in the patients with non-ringed (proximal) and the patients with ring-enforced conduit (distal), P = 0.004. In 6 patients, a surgical revision of the conduit was performed; 3 of them died prior to BSCPA. Another 6 patients had a stent implantation and 3 were treated with balloon dilatation followed by a BSCPA in the subsequent 2 weeks. All patients who were treated interventionally for RV-PA conduit obstruction had a successful BSCPA. Patients who received a surgical RV-PA conduit revision had a significantly higher interstage (P = 0.044) and overall mortality (P = 0.011) than those who received a stent or balloon dilatation of the stenosis followed by an early BSCPA. RV-PA conduit obstruction after Norwood I procedure in patients with HLHS can be safely and effectively treated by stent implantation, balloon dilatation and early BSCPA. Surgical revision of the RV-PA conduit can be reserved for patients in whom an interventional approach fails, and an early BSCPA is not an option.

  7. Magma shearing and friction in the volcanic conduit: A crystal constraint

    Science.gov (United States)

    Wallace, P. A.; Kendrick, J. E.; Henton De Angelis, S.; Ashworth, J. D.; Coats, R.; Miwa, T.; Mariani, E.; Lavallée, Y.

    2017-12-01

    Magma shearing and friction processes in the shallow volcanic conduit are typical manifestations of strain localisation, which in turn can have an influential role on magma ascent dynamics. The thermal consequences of such events could drive the destabilisation of magma and thus dictate the style of activity at the surface. Shear heating and fault friction are prime candidates for the generation of significant quantities of heat. Here we use a combination of field and experimental evidence to investigate how crystals can act as sensitive recorders of both physical and chemical processes occurring in the shallow volcanic conduit. Spine extrusion during the closing of the 1991-95 eruption at Unzen volcano, Japan, provided the unique opportunity to investigate marginal shear zone formation, which preserves a relic of the deformation during magma ascent. Our results show that crystals can effectively act as a deformation marker during magma ascent through the viscous-brittle transition by accommodating strain in the form of crystal plasticity before fracturing (comminution). Electron backscatter diffraction (EBSD) reveals up to 40° lattice distortion of biotite phenocrysts in zones of high shear, with negligible plasticity further away. Plagioclase microlites display a systematic plastic response to an increase in shear intensity, as recorded by an increase in lattice distortion towards the spine margin of up to 9°. This localisation of strain within the shear zone is also accompanied by the destabilisation of hydrous mineral phases (i.e. amphibole), compaction of pores (23-13% Φ), glass devitrification and magnetic anomalies. The narrow zone of disequilibrium textures suggests the likely effect of a thermal input due to strain localisation being the contributing factor. These observations are complimented by high-temperature high-velocity rotary shear experiments which simulate the deformation evolution during shear. Hence, understanding these shallow volcanic

  8. Gate valve performance prediction

    International Nuclear Information System (INIS)

    Harrison, D.H.; Damerell, P.S.; Wang, J.K.; Kalsi, M.S.; Wolfe, K.J.

    1994-01-01

    The Electric Power Research Institute is carrying out a program to improve the performance prediction methods for motor-operated valves. As part of this program, an analytical method to predict the stem thrust required to stroke a gate valve has been developed and has been assessed against data from gate valve tests. The method accounts for the loads applied to the disc by fluid flow and for the detailed mechanical interaction of the stem, disc, guides, and seats. To support development of the method, two separate-effects test programs were carried out. One test program determined friction coefficients for contacts between gate valve parts by using material specimens in controlled environments. The other test program investigated the interaction of the stem, disc, guides, and seat using a special fixture with full-sized gate valve parts. The method has been assessed against flow-loop and in-plant test data. These tests include valve sizes from 3 to 18 in. and cover a considerable range of flow, temperature, and differential pressure. Stem thrust predictions for the method bound measured results. In some cases, the bounding predictions are substantially higher than the stem loads required for valve operation, as a result of the bounding nature of the friction coefficients in the method

  9. Stanford, Duke, Rice,... and Gates?

    Science.gov (United States)

    Carey, Kevin

    2009-01-01

    This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

  10. A novel conduit-based coaptation device for primary nerve repair.

    Science.gov (United States)

    Bamba, Ravinder; Riley, D Colton; Kelm, Nathaniel D; Cardwell, Nancy; Pollins, Alonda C; Afshari, Ashkan; Nguyen, Lyly; Dortch, Richard D; Thayer, Wesley P

    2018-06-01

    Conduit-based nerve repairs are commonly used for small nerve gaps, whereas primary repair may be performed if there is no tension on nerve endings. We hypothesize that a conduit-based nerve coaptation device will improve nerve repair outcomes by avoiding sutures at the nerve repair site and utilizing the advantages of a conduit-based repair. The left sciatic nerves of female Sprague-Dawley rats were transected and repaired using a novel conduit-based device. The conduit-based device group was compared to a control group of rats that underwent a standard end-to-end microsurgical repair of the sciatic nerve. Animals underwent behavioral assessments at weekly intervals post-operatively using the sciatic functional index (SFI) test. Animals were sacrificed at four weeks to obtain motor axon counts from immunohistochemistry. A sub-group of animals were sacrificed immediately post repair to obtain MRI images. SFI scores were superior in rats which received conduit-based repairs compared to the control group. Motor axon counts distal to the injury in the device group at four weeks were statistically superior to the control group. MRI tractography was used to demonstrate repair of two nerves using the novel conduit device. A conduit-based nerve coaptation device avoids sutures at the nerve repair site and leads to improved outcomes in a rat model. Conduit-based nerve repair devices have the potential to standardize nerve repairs while improving outcomes.

  11. Evidence for Arbovirus Dissemination Conduits from the Mosquito (Diptera: Culicidae) Midgut

    National Research Council Canada - National Science Library

    Romoser, William

    2004-01-01

    .... Experiments using Venezuelan equine encephalitis viral replicon particles, which express the green fluorescent protein gene in cells, indicate the operation of tissue conduits, possibly involving...

  12. Regenerative potential of silk conduits in repair of peripheral nerve injury in adult rats.

    Science.gov (United States)

    Huang, W; Begum, R; Barber, T; Ibba, V; Tee, N C H; Hussain, M; Arastoo, M; Yang, Q; Robson, L G; Lesage, S; Gheysens, T; Skaer, Nicholas J V; Knight, D P; Priestley, J V

    2012-01-01

    Various attempts have been made to develop artificial conduits for nerve repair, but with limited success. We describe here conduits made from Bombyx mori regenerated silk protein, and containing luminal fibres of Spidrex(®), a silk-based biomaterial with properties similar to those of spider silk. Assessment in vitro demonstrated that Spidrex(®) fibres support neurite outgrowth. For evaluation in vivo, silk conduits 10 mm in length and containing 0, 100, 200 or 300 luminal Spidrex(®) fibres, were implanted to bridge an 8 mm gap in the rat sciatic nerve. At 4 weeks, conduits containing 200 luminal Spidrex(®) fibres (PN200) supported 62% and 59% as much axon growth as autologous nerve graft controls at mid-conduit and distal nerve respectively. Furthermore, Spidrex(®) conduits displayed similar Schwann cell support and macrophage response to controls. At 12 weeks, animals implanted with PN200 conduits showed similar numbers of myelinated axons (81%) to controls, similar gastrocnemius muscle innervation, and similar hindpaw stance assessed by Catwalk footprint analysis. Plantar skin innervation was 73% of that of controls. PN200 Spidrex(®) conduits were also effective at bridging longer (11 and 13 mm) gaps. Our results show that Spidrex(®) conduits promote excellent axonal regeneration and function recovery, and may have potential for clinical application. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Double optical gating

    Science.gov (United States)

    Gilbertson, Steve

    The observation and control of dynamics in atomic and molecular targets requires the use of laser pulses with duration less than the characteristic timescale of the process which is to be manipulated. For electron dynamics, this time scale is on the order of attoseconds where 1 attosecond = 10 -18 seconds. In order to generate pulses on this time scale, different gating methods have been proposed. The idea is to extract or "gate" a single pulse from an attosecond pulse train and switch off all the other pulses. While previous methods have had some success, they are very difficult to implement and so far very few labs have access to these unique light sources. The purpose of this work is to introduce a new method, called double optical gating (DOG), and to demonstrate its effectiveness at generating high contrast single isolated attosecond pulses from multi-cycle lasers. First, the method is described in detail and is investigated in the spectral domain. The resulting attosecond pulses produced are then temporally characterized through attosecond streaking. A second method of gating, called generalized double optical gating (GDOG), is also introduced. This method allows attosecond pulse generation directly from a carrier-envelope phase un-stabilized laser system for the first time. Next the methods of DOG and GDOG are implemented in attosecond applications like high flux pulses and extreme broadband spectrum generation. Finally, the attosecond pulses themselves are used in experiments. First, an attosecond/femtosecond cross correlation is used for characterization of spatial and temporal properties of femtosecond pulses. Then, an attosecond pump, femtosecond probe experiment is conducted to observe and control electron dynamics in helium for the first time.

  14. Convection in a volcanic conduit recorded by bubbles

    Science.gov (United States)

    Carey, Rebecca J.; Manga, Michael; Degruyter, Wim; Gonnermann, Helge M.; Swanson, Donald; Houghton, Bruce F.; Orr, Tim R.; Patrick, Matthew R.

    2013-01-01

    Microtextures of juvenile pyroclasts from Kīlauea’s (Hawai‘i) early A.D. 2008 explosive activity record the velocity and depth of convection within the basaltic magma-filled conduit. We use X-ray microtomography (μXRT) to document the spatial distribution of bubbles. We find small bubbles (radii from 5 μm to 70 μm) in a halo surrounding larger millimeter-size bubbles. This suggests that dissolved water was enriched around the larger bubbles—the opposite of what is expected if bubbles grow as water diffuses into the bubble. Such volatile enrichment implies that the volatiles within the large bubbles were redissolving into the melt as they descended into the conduit by the downward motion of convecting magma within the lava lake. The thickness of the small bubble halo is ∼100–150 μm, consistent with water diffusing into the melt on time scales on the order of 103 s. Eruptions, triggered by rockfall, rapidly exposed this magma to lower pressures, and the haloes of melt with re-dissolved water became sufficiently supersaturated to cause nucleation of the population of smaller bubbles. The required supersaturation pressures are consistent with a depth of a few hundred meters and convection velocities of the order of 0.1 m s−1, similar to the circulation velocity observed on the surface of the Halema‘uma‘u lava lake.

  15. Conduit for high temperature transfer of molten semiconductor crystalline material

    Science.gov (United States)

    Fiegl, George (Inventor); Torbet, Walter (Inventor)

    1983-01-01

    A conduit for high temperature transfer of molten semiconductor crystalline material consists of a composite structure incorporating a quartz transfer tube as the innermost member, with an outer thermally insulating layer designed to serve the dual purposes of minimizing heat losses from the quartz tube and maintaining mechanical strength and rigidity of the conduit at the elevated temperatures encountered. The composite structure ensures that the molten semiconductor material only comes in contact with a material (quartz) with which it is compatible, while the outer layer structure reinforces the quartz tube, which becomes somewhat soft at molten semiconductor temperatures. To further aid in preventing cooling of the molten semiconductor, a distributed, electric resistance heater is in contact with the surface of the quartz tube over most of its length. The quartz tube has short end portions which extend through the surface of the semiconductor melt and which are lef bare of the thermal insulation. The heater is designed to provide an increased heat input per unit area in the region adjacent these end portions.

  16. Exploring Ultimate Water Capillary Evaporation in Nanoscale Conduits.

    Science.gov (United States)

    Li, Yinxiao; Alibakhshi, Mohammad Amin; Zhao, Yihong; Duan, Chuanhua

    2017-08-09

    Capillary evaporation in nanoscale conduits is an efficient heat/mass transfer strategy that has been widely utilized by both nature and mankind. Despite its broad impact, the ultimate transport limits of capillary evaporation in nanoscale conduits, governed by the evaporation/condensation kinetics at the liquid-vapor interface, have remained poorly understood. Here we report experimental study of the kinetic limits of water capillary evaporation in two dimensional nanochannels using a novel hybrid channel design. Our results show that the kinetic-limited evaporation fluxes break down the limits predicated by the classical Hertz-Knudsen equation by an order of magnitude, reaching values up to 37.5 mm/s with corresponding heat fluxes up to 8500 W/cm 2 . The measured evaporation flux increases with decreasing channel height and relative humidity but decreases as the channel temperature decreases. Our findings have implications for further understanding evaporation at the nanoscale and developing capillary evaporation-based technologies for both energy- and bio-related applications.

  17. Documentation of a Conduit Flow Process (CFP) for MODFLOW-2005

    Science.gov (United States)

    Shoemaker, W. Barclay; Kuniansky, Eve L.; Birk, Steffen; Bauer, Sebastian; Swain, Eric D.

    2007-01-01

    This report documents the Conduit Flow Process (CFP) for the modular finite-difference ground-water flow model, MODFLOW-2005. The CFP has the ability to simulate turbulent ground-water flow conditions by: (1) coupling the traditional ground-water flow equation with formulations for a discrete network of cylindrical pipes (Mode 1), (2) inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 2), or (3) simultaneously coupling a discrete pipe network while inserting a high-conductivity flow layer that can switch between laminar and turbulent flow (Mode 3). Conduit flow pipes (Mode 1) may represent dissolution or biological burrowing features in carbonate aquifers, voids in fractured rock, and (or) lava tubes in basaltic aquifers and can be fully or partially saturated under laminar or turbulent flow conditions. Preferential flow layers (Mode 2) may represent: (1) a porous media where turbulent flow is suspected to occur under the observed hydraulic gradients; (2) a single secondary porosity subsurface feature, such as a well-defined laterally extensive underground cave; or (3) a horizontal preferential flow layer consisting of many interconnected voids. In this second case, the input data are effective parameters, such as a very high hydraulic conductivity, representing multiple features. Data preparation is more complex for CFP Mode 1 (CFPM1) than for CFP Mode 2 (CFPM2). Specifically for CFPM1, conduit pipe locations, lengths, diameters, tortuosity, internal roughness, critical Reynolds numbers (NRe), and exchange conductances are required. CFPM1, however, solves the pipe network equations in a matrix that is independent of the porous media equation matrix, which may mitigate numerical instability associated with solution of dual flow components within the same matrix. CFPM2 requires less hydraulic information and knowledge about the specific location and hydraulic properties of conduits, and turbulent flow is approximated by

  18. A double-gate double-feedback JFET charge-sensitive preamplifier

    International Nuclear Information System (INIS)

    Fazzi, A.

    1996-01-01

    A new charge-sensitive preamplifier (CSP) without a physical resistance in the feedback is presented. The input device has to be a double-gate JFET. In this new preamplifier configuration the feedback capacitor is continuously discharged by means of a second DC current feedback loop closed through the bottom gate of the input JFET. The top gate-channel junction works as usual in reverse bias, the bottom gate-channel is forward biased. A fraction of the current injected by the bottom gate reaches the top gate discharging the feedback capacitor. The n-channel double-gate JFET is considered from the viewpoint of the restoring action as a parasitic p-n-p ''transversal'' bipolar junction transistor. The new preamplifier is also suited for detectors operating at room temperature with leakage current which may vary with time. The DC behaviour and the dynamic behaviour of the circuit is analyzed and new measurements presented. (orig.)

  19. Drill pipes and casings utilizing multi-conduit tubular; Flerkanals roerstreng

    Energy Technology Data Exchange (ETDEWEB)

    Curlett, H.B.

    1997-04-23

    The invention relates to a multi-conduit tubular having fluid conduits and electrical conduits, with associated surface fluid and electrical commutators, and downhole sensors for providing surface monitors with instantaneous formation data. Each tubular includes a plurality of uniform linear conduits there through, with a gasket seal plate interposed between joined tubular for assuring a high pressure seal between joined conduits. the seal plate includes an intermediate electrical connector for connecting electrical conduit connectors of one tubular to another. A coupling collar with uniform diameter internal coarse and fine threads joins the tubular ends having similar threads by differential thread action without respective tubular rotation. Each tubular end includes an inter-engaging index recess and index lug, and drive recesses and lugs for maintaining angular registry of the tubular string and for driving one drill tubular with another. A fluid commutator includes a rotating shaft with passages connected to the tubular conduits, and rotating in a manifold having annular grooves in communication with the shaft passages and external fluid sources. An adaptor couples each commutator shaft passage to one or more tubular conduits. Slip rings on a quill shaft and stationary brush means provide electrical continuity from the electrical conduit wires to surface equipment. A cross-over sub includes formation parameter sensors and telemetry equipment in a blocked off portion of a fluid conduit. An annular accumulator connected with the well bore annulus applies a pressure thereto in response to downhole sensors to change the effective density of the drill mud. The multi-conduit tubular is further adapted for use as a well casing to provide downhole access of a plurality of fluids and electrical parameter sensors. 28 figs.

  20. Silicic magma differentiation in ascent conduits. Experimental constraints

    Science.gov (United States)

    Rodríguez, Carmen; Castro, Antonio

    2017-02-01

    Crystallization of water-bearing silicic magmas in a dynamic thermal boundary layer is reproduced experimentally by using the intrinsic thermal gradient of piston-cylinder assemblies. The standard AGV2 andesite under water-undersaturated conditions is set to crystallize in a dynamic thermal gradient of about 35 °C/mm in 10 mm length capsules. In the hotter area of the capsule, the temperature is initially set at 1200 °C and decreases by programmed cooling at two distinct rates of 0.6 and 9.6 °C/h. Experiments are conducted in horizontally arranged assemblies in a piston cylinder apparatus to avoid any effect of gravity settling and compaction of crystals in long duration runs. The results are conclusive about the effect of water-rich fluids that are expelled out the crystal-rich zone (mush), where water saturation is reached by second boiling in the interstitial liquid. Expelled fluids migrate to the magma ahead of the solidification front contributing to a progressive enrichment in the fluxed components SiO2, K2O and H2O. The composition of water-rich fluids is modelled by mass balance using the chemical composition of glasses (quenched melt). The results are the basis for a model of granite magma differentiation in thermally-zoned conduits with application of in-situ crystallization equations. The intriguing textural and compositional features of the typical autoliths, accompanying granodiorite-tonalite batholiths, can be explained following the results of this study, by critical phenomena leading to splitting of an initially homogeneous magma into two magma systems with sharp boundaries. Magma splitting in thermal boundary layers, formed at the margins of ascent conduits, may operate for several km distances during magma transport from deep sources at the lower crust or upper mantle. Accordingly, conduits may work as chromatographic columns contributing to increase the silica content of ascending magmas and, at the same time, leave behind residual mushes that

  1. Characterization of molecule and particle transport through nanoscale conduits

    Science.gov (United States)

    Alibakhshi, Mohammad Amin

    Nanofluidic devices have been of great interest due to their applications in variety of fields, including energy conversion and storage, water desalination, biological and chemical separations, and lab-on-a-chip devices. Although these applications cross the boundaries of many different disciplines, they all share the demand for understanding transport in nanoscale conduits. In this thesis, different elusive aspects of molecule and particle transport through nanofluidic conduits are investigated, including liquid and ion transport in nanochannels, diffusion- and reaction-governed enzyme transport in nanofluidic channels, and finally translocation of nanobeads through nanopores. Liquid or solvent transport through nanoconfinements is an essential yet barely characterized component of any nanofluidic systems. In the first chapter, water transport through single hydrophilic nanochannels with heights down to 7 nm is experimentally investigated using a new measurement technique. This technique has been developed based on the capillary flow and a novel hybrid nanochannel design and is capable of characterizing flow in both single nanoconduits as well as nanoporous media. The presence of a 0.7 nm thick hydration layer on hydrophilic surfaces and its effect on increasing the hydraulic resistance of the nanochannels is verified. Next, ion transport in a new class of nanofluidic rectifiers is theoretically and experimentally investigated. These so called nanofluidic diodes are nanochannels with asymmetric geometries which preferentially allow ion transport in one direction. A nondimensional number as a function of electrolyte concentration, nanochannel dimensions, and surface charge is derived that summarizes the rectification behavior of this system. In the fourth chapter, diffusion- and reaction-governed enzyme transport in nanofluidic channels is studied and the theoretical background necessary for understanding enzymatic activity in nanofluidic channels is presented. A

  2. Noise Gating Solar Images

    Science.gov (United States)

    DeForest, Craig; Seaton, Daniel B.; Darnell, John A.

    2017-08-01

    I present and demonstrate a new, general purpose post-processing technique, "3D noise gating", that can reduce image noise by an order of magnitude or more without effective loss of spatial or temporal resolution in typical solar applications.Nearly all scientific images are, ultimately, limited by noise. Noise can be direct Poisson "shot noise" from photon counting effects, or introduced by other means such as detector read noise. Noise is typically represented as a random variable (perhaps with location- or image-dependent characteristics) that is sampled once per pixel or once per resolution element of an image sequence. Noise limits many aspects of image analysis, including photometry, spatiotemporal resolution, feature identification, morphology extraction, and background modeling and separation.Identifying and separating noise from image signal is difficult. The common practice of blurring in space and/or time works because most image "signal" is concentrated in the low Fourier components of an image, while noise is evenly distributed. Blurring in space and/or time attenuates the high spatial and temporal frequencies, reducing noise at the expense of also attenuating image detail. Noise-gating exploits the same property -- "coherence" -- that we use to identify features in images, to separate image features from noise.Processing image sequences through 3-D noise gating results in spectacular (more than 10x) improvements in signal-to-noise ratio, while not blurring bright, resolved features in either space or time. This improves most types of image analysis, including feature identification, time sequence extraction, absolute and relative photometry (including differential emission measure analysis), feature tracking, computer vision, correlation tracking, background modeling, cross-scale analysis, visual display/presentation, and image compression.I will introduce noise gating, describe the method, and show examples from several instruments (including SDO

  3. A quantum Fredkin gate

    Science.gov (United States)

    Patel, Raj B.; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C.; Pryde, Geoff J.

    2016-01-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently. PMID:27051868

  4. A quantum Fredkin gate.

    Science.gov (United States)

    Patel, Raj B; Ho, Joseph; Ferreyrol, Franck; Ralph, Timothy C; Pryde, Geoff J

    2016-03-01

    Minimizing the resources required to build logic gates into useful processing circuits is key to realizing quantum computers. Although the salient features of a quantum computer have been shown in proof-of-principle experiments, difficulties in scaling quantum systems have made more complex operations intractable. This is exemplified in the classical Fredkin (controlled-SWAP) gate for which, despite theoretical proposals, no quantum analog has been realized. By adding control to the SWAP unitary, we use photonic qubit logic to demonstrate the first quantum Fredkin gate, which promises many applications in quantum information and measurement. We implement example algorithms and generate the highest-fidelity three-photon Greenberger-Horne-Zeilinger states to date. The technique we use allows one to add a control operation to a black-box unitary, something that is impossible in the standard circuit model. Our experiment represents the first use of this technique to control a two-qubit operation and paves the way for larger controlled circuits to be realized efficiently.

  5. Scaling Trapped Ion Quantum Computers Using Fast Gates and Microtraps

    Science.gov (United States)

    Ratcliffe, Alexander K.; Taylor, Richard L.; Hope, Joseph J.; Carvalho, André R. R.

    2018-06-01

    Most attempts to produce a scalable quantum information processing platform based on ion traps have focused on the shuttling of ions in segmented traps. We show that an architecture based on an array of microtraps with fast gates will outperform architectures based on ion shuttling. This system requires higher power lasers but does not require the manipulation of potentials or shuttling of ions. This improves optical access, reduces the complexity of the trap, and reduces the number of conductive surfaces close to the ions. The use of fast gates also removes limitations on the gate time. Error rates of 10-5 are shown to be possible with 250 mW laser power and a trap separation of 100 μ m . The performance of the gates is shown to be robust to the limitations in the laser repetition rate and the presence of many ions in the trap array.

  6. Twenty years of cable-in-conduit conductors: 1975-1995

    International Nuclear Information System (INIS)

    Dresner, L.

    1995-01-01

    This paper reviews our progress during the last two decades in understanding cable-in-conduit conductors. The emphasis is on the physical principles governing the behavior of cable-in-conduit conductors, and no detailed mathematics is presented. The paper is constructed as a historical narrative

  7. 26 CFR 1.58-2 - General rules for conduit entities; partnerships and partners.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 1 2010-04-01 2010-04-01 true General rules for conduit entities; partnerships...; partnerships and partners. (a) General rules for conduit entities. Sections 1.58-3 through 1.58-6 provide rules... example, if a trust has $100,000 of capital gains for the taxable year, all of which are distributed to A...

  8. Midterm performance of a novel restorative pulmonary valved conduit: preclinical results

    NARCIS (Netherlands)

    Soliman, Osama I.; Miyazaki, Yosuke; Abdelghani, Mohammad; Brugmans, Marieke; Witsenburg, Maarten; Onuma, Yoshinobu; Cox, Martijn; Serruys, Patrick W.

    2017-01-01

    Aims: The Xeltis bioabsorbable pulmonary valved conduit (XPV), designed to guide functional restoration of patients' own tissue, is potentially more durable than current pulmonary bioprosthetic valves/valved conduits. The aim of this study was to assess the haemodynamic performance of the novel XPV

  9. 78 FR 56872 - City of Barre, Vermont; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-09-16

    ..., Vermont; Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting... construct a qualifying conduit hydropower facility, pursuant to section 30 of the Federal Power Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of 2013 (HREA). The Nelson Street 17 kW...

  10. 78 FR 66355 - Pleasant Grove City, UT; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-11-05

    ... City, UT; Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and... Grove City, Utah (Pleasant Grove) filed a notice of intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of the Federal Power Act, as amended by section 4 of the Hydropower...

  11. 78 FR 61987 - Corbett Water District; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-10-09

    ... District; Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting... construct a qualifying conduit hydropower facility, pursuant to section 30 of the Federal Power Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of 2013 (HREA). The Corbett Hydroelectric...

  12. 78 FR 53752 - City of Sandpoint, Idaho; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-08-30

    ... Sandpoint, Idaho; Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and... intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of the Federal Power Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of 2013 (HREA). The Little...

  13. 78 FR 61985 - City of Astoria, Oregon; Notice of Preliminary Determination of a Qualifying Conduit Hydropower...

    Science.gov (United States)

    2013-10-09

    ..., Oregon; Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting... of intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of the Federal Power Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of 2013 (HREA). The...

  14. 78 FR 63176 - Notice of Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting...

    Science.gov (United States)

    2013-10-23

    ... Preliminary Determination of a Qualifying Conduit Hydropower Facility and Soliciting Comments and Motions To... of intent to construct a qualifying conduit hydropower facility, pursuant to section 30 of the Federal Power Act, as amended by section 4 of the Hydropower Regulatory Efficiency Act of 2013 (HREA). The...

  15. Studying the causes for corrosive destruction of water conduits

    Energy Technology Data Exchange (ETDEWEB)

    Azamatova, F I; Kulinichev, G P; Porubov, I S

    1979-01-01

    Pipes from different oil and gas production administrations were selected for X-ray and metallographic studies of the cause of corrosive destruction. The chemical composition and mechanical properties of the pipe material are presented in tables. The phase composition of the corrosion products was studied by X-rays. The complex structure of the layer made up of the corrosion products was taken into consideration. The studies were conducted in an X-ray diffraction chamber. The obtained results are presented in a table. The metallographic studies showed that a significant corrosive damage of the materials of water conduits occurs as a result of the development of local corrosion processes, caused by the substantive heterogeneity of the structure of the metal, related to the nonuniform distribution of the pearlite because of carbon liquidation.

  16. Injunctions against mere conduit of information protected by copyright

    DEFF Research Database (Denmark)

    Sandfeld Jakobsen, Søren; Petersen, Clement Salung

    2011-01-01

    This paper includes an in-depth analysis of EU law and Scandinavian law on injunctions against internet access providers (IAPs) performing as mere conduit of information protected by copyright. In recent Scandinavian case law, courts have granted preliminary injunctions which have caused IAPs...... to either shut down specific internet connections allegedly used to infringe copyright or to block access to internet content, which allegedly infringed applicable copyright rules. This paper considers some significant legal challenges, which are emerging in the wake of this case law, and which should...... requires rules, which take into due consideration the special aspects related to enforcement of copyright on the internet through IAPs. Secondly, it is shown that the termination of internet connections and the blocking of access to internet content may not support the public policies behind copyright law...

  17. Hot upwelling conduit beneath the Atlas Mountains, Morocco

    Science.gov (United States)

    Sun, Daoyuan; Miller, Meghan S.; Holt, Adam F.; Becker, Thorsten W.

    2014-11-01

    The Atlas Mountains of Morocco display high topography, no deep crustal root, and regions of localized Cenozoic alkaline volcanism. Previous seismic imaging and geophysical studies have implied a hot mantle upwelling as the source of the volcanism and high elevation. However, the existence, shape, and physical properties of an associated mantle anomaly are debated. Here we use seismic waveform analysis from a broadband deployment and geodynamic modeling to define the physical properties and morphology of the anomaly. The imaged low-velocity structure extends to ~200 km beneath the Atlas and appears ~350 K hotter than the ambient mantle with possible partial melting. It includes a lateral conduit, which suggests that the Quaternary volcanism arises from the upper mantle. Moreover, the shape and temperature of the imaged anomaly indicate that the unusually high topography of the Atlas Mountains is due to active mantle support.

  18. Investigating the influence of conduit residues on polyurethane plates

    Directory of Open Access Journals (Sweden)

    Rachel Faverzani Magnago

    Full Text Available Abstract Converting waste into a product similar to the original one or into another useful product is to save energy, protect natural resources, and bring back to the production cycle what was discarded. In that direction, new polyurethane-based composites have been developed by incorporating 5%, 10%, 15%, and 20% PVC conduit discarded by the construction industry. The objective of this study was to investigate the interaction between the phases of waste incorporation and the effect upon the new material properties. The samples were produced by the polycondensation process. Microstructural analysis revealed a reduction in pore size across the polymer matrix. However, there were no changes in thermal insulation, water absorption, compressive strength, and burning rate tests and in the thermogravimetric analysis and differential scanning calorimetry. The results from this study showed that the replacement of raw material by waste did not affect its properties.

  19. Cable-in-conduit conductor optimization for fusion magnet applications

    International Nuclear Information System (INIS)

    Miller, J.R.; Kerns, J.A.

    1987-01-01

    Careful design of the toroidal-field (TF) and poloidal-field (PF) coils in a tokamak machine using cable-in-conduit conductors (CICC) can result in quite high overall winding-pack current densities - even with the high nuclear heat loads that may be imposed in operating a fusion reactor - and thereby help reduce the overall machine size. In our design process, we systematically examined the operational environment of a magnet, e.g., mechanical stresses, current, field, heat load, coolant temperature, and cooldown stresses, to determine the optimum amounts of copper, superconductor, helium, and sheath material for the CICC. This process is being used to design the superconducting magnet systems that comprise the Tokamak Ignition/Burn Experimental Reactor (TIBER II). 13 refs., 2 figs

  20. Novel technique for airless connection of artificial heart to vascular conduits.

    Science.gov (United States)

    Karimov, Jamshid H; Gao, Shengqiang; Dessoffy, Raymond; Sunagawa, Gengo; Sinkewich, Martin; Grady, Patrick; Sale, Shiva; Moazami, Nader; Fukamachi, Kiyotaka

    2017-12-01

    Successful implantation of a total artificial heart relies on multiple standardized procedures, primarily the resection of the native heart, and exacting preparation of the atrial and vascular conduits for pump implant and activation. Achieving secure pump connections to inflow/outflow conduits is critical to a successful outcome. During the connection process, however, air may be introduced into the circulation, traveling to the brain and multiple organs. Such air emboli block blood flow to these areas and are detrimental to long-term survival. A correctly managed pump-to-conduit connection prevents air from collecting in the pump and conduits. To further optimize pump-connection techniques, we have developed a novel connecting sleeve that enables airless connection of the Cleveland Clinic continuous-flow total artificial heart (CFTAH) to the conduits. In this brief report, we describe the connecting sleeve design and our initial results from two acute in vivo implantations using a scaled-down version of the CFTAH.

  1. A gating grid driver for time projection chambers

    Energy Technology Data Exchange (ETDEWEB)

    Tangwancharoen, S.; Lynch, W.G.; Barney, J.; Estee, J. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Shane, R. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Tsang, M.B., E-mail: tsang@nscl.msu.edu [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Zhang, Y. [Department of Physics, Tsinghua University, Beijing 100084 (China); Isobe, T.; Kurata-Nishimura, M. [RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Murakami, T. [Department of Physics, Kyoto University, Kita-shirakawa, Kyoto 606–8502 (Japan); Xiao, Z.G. [Department of Physics, Tsinghua University, Beijing 100084 (China); Zhang, Y.F. [College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China)

    2017-05-01

    A simple but novel driver system has been developed to operate the wire gating grid of a Time Projection Chamber (TPC). This system connects the wires of the gating grid to its driver via low impedance transmission lines. When the gating grid is open, all wires have the same voltage allowing drift electrons, produced by the ionization of the detector gas molecules, to pass through to the anode wires. When the grid is closed, the wires have alternating higher and lower voltages causing the drift electrons to terminate at the more positive wires. Rapid opening of the gating grid with low pickup noise is achieved by quickly shorting the positive and negative wires to attain the average bias potential with N-type and P-type MOSFET switches. The circuit analysis and simulation software SPICE shows that the driver restores the gating grid voltage to 90% of the opening voltage in less than 0.20 µs, for small values of the termination resistors. When tested in the experimental environment of a time projection chamber larger termination resistors were chosen so that the driver opens the gating grid in 0.35 µs. In each case, opening time is basically characterized by the RC constant given by the resistance of the switches and terminating resistors and the capacitance of the gating grid and its transmission line. By adding a second pair of N-type and P-type MOSFET switches, the gating grid is closed by restoring 99% of the original charges to the wires within 3 µs.

  2. Multiple Independent Gate FETs: How Many Gates Do We Need?

    OpenAIRE

    Amarù, Luca; Hills, Gage; Gaillardon, Pierre-Emmanuel; Mitra, Subhasish; De Micheli, Giovanni

    2015-01-01

    Multiple Independent Gate Field Effect Transistors (MIGFETs) are expected to push FET technology further into the semiconductor roadmap. In a MIGFET, supplementary gates either provide (i) enhanced conduction properties or (ii) more intelligent switching functions. In general, each additional gate also introduces a side implementation cost. To enable more efficient digital systems, MIGFETs must leverage their expressive power to realize complex logic circuits with few physical resources. Rese...

  3. Pressure locking and thermal binding of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, E.M.

    1996-12-01

    Pressure locking and thermal binding represent potential common mode failure mechanisms that can cause safety-related power-operated gate valves to fail in the closed position, thus rendering redundant safety-related systems incapable of performing their safety functions. Supplement 6 to Generic Letter 89-10, {open_quotes}Safety-Related Motor-Operated Gate Valve Testing and Surveillance,{close_quotes} provided an acceptable approach to addressing pressure locking and thermal binding of gate valves. More recently, the NRC has issued Generic Letter 95-07, {open_quotes}Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves,{close_quotes} to request that licensees take certain actions to ensure that safety-related power-operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions within the current licensing bases. Over the past two years, several plants in Region I determined that valves in certain systems were potentially susceptible to pressure locking and thermal binding, and have taken various corrective actions. The NRC Region I Systems Engineering Branch has been actively involved in the inspection of licensee actions in response to the pressure locking and thermal binding issue. Region I continues to maintain an active involvement in this area, including participation with the Office of Nuclear Reactor Regulation in reviewing licensee responses to Generic Letter 95-07.

  4. 100-nm gate lithography for double-gate transistors

    Science.gov (United States)

    Krasnoperova, Azalia A.; Zhang, Ying; Babich, Inna V.; Treichler, John; Yoon, Jung H.; Guarini, Kathryn; Solomon, Paul M.

    2001-09-01

    The double gate field effect transistor (FET) is an exploratory device that promises certain performance advantages compared to traditional CMOS FETs. It can be scaled down further than the traditional devices because of the greater electrostatic control by the gates on the channel (about twice as short a channel length for the same gate oxide thickness), has steeper sub-threshold slope and about double the current for the same width. This paper presents lithographic results for double gate FET's developed at IBM's T. J. Watson Research Center. The device is built on bonded wafers with top and bottom gates self-aligned to each other. The channel is sandwiched between the top and bottom polysilicon gates and the gate length is defined using DUV lithography. An alternating phase shift mask was used to pattern gates with critical dimensions of 75 nm, 100 nm and 125 nm in photoresist. 50 nm gates in photoresist have also been patterned by 20% over-exposure of nominal 100 nm lines. No trim mask was needed because of a specific way the device was laid out. UV110 photoresist from Shipley on AR-3 antireflective layer were used. Process windows, developed and etched patterns are presented.

  5. Development and Implementation of a Segment/Junction Box Level Database for the ITS Fiber Optic Conduit Network

    Science.gov (United States)

    2012-03-01

    This project initiated the development of a computerized database of ITS facilities, including conduits, junction : boxes, cameras, connections, etc. The current system consists of a database of conduit sections of various lengths. : Over the length ...

  6. Feasibility study of multi-pass respiratory-gated helical tomotherapy of a moving target via binary MLC closure

    Science.gov (United States)

    Kim, Bryan; Chen, Jeff; Kron, Tomas; Battista, Jerry

    2010-11-01

    Gated radiotherapy of lung lesions is particularly complex for helical tomotherapy, due to the simultaneous motions of its three subsystems (gantry, couch and collimator). We propose a new way to implement gating for helical tomotherapy, namely multi-pass respiratory gating. In this method, gating is achieved by delivering only the beam projections that occur within a respiratory gating window, while blocking the rest of the beam projections by fully closing all collimator leaves. Due to the continuous couch motion, the planned beam projections must be delivered over multiple passes of radiation deliveries. After each pass, the patient couch is reset to its starting position, and the treatment recommences at a different phase of tumour motion to 'fill in' the previously blocked beam projections. The gating process may be repeated until the plan dose is delivered (full gating), or halted after a certain number of passes, with the entire remaining dose delivered in a final pass without gating (partial gating). The feasibility of the full gating approach was first tested for sinusoidal target motion, through experimental measurements with film and computer simulation. The optimal gating parameters for full and partial gating methods were then determined for various fractionation schemes through computer simulation, using a patient respiratory waveform. For sinusoidal motion, the PTV dose deviations of -29 to 5% observed without gating were reduced to range from -1 to 3% for a single fraction, with a 4 pass full gating. For a patient waveform, partial gating required fewer passes than full gating for all fractionation schemes. For a single fraction, the maximum allowed residual motion was only 4 mm, requiring large numbers of passes for both full (12) and partial (7 + 1) gating methods. The number of required passes decreased significantly for 3 and 30 fractions, allowing residual motion up to 7 mm. Overall, the multi-pass gating technique was shown to be a promising

  7. Feasibility study of multi-pass respiratory-gated helical tomotherapy of a moving target via binary MLC closure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bryan; Chen, Jeff; Battista, Jerry [London Regional Cancer Program, London Health Sciences Centre, London, ON (Canada); Kron, Tomas, E-mail: bryan.kim@lhsc.on.c [Peter MacCallum Cancer Center, Melbourne (Australia)

    2010-11-21

    Gated radiotherapy of lung lesions is particularly complex for helical tomotherapy, due to the simultaneous motions of its three subsystems (gantry, couch and collimator). We propose a new way to implement gating for helical tomotherapy, namely multi-pass respiratory gating. In this method, gating is achieved by delivering only the beam projections that occur within a respiratory gating window, while blocking the rest of the beam projections by fully closing all collimator leaves. Due to the continuous couch motion, the planned beam projections must be delivered over multiple passes of radiation deliveries. After each pass, the patient couch is reset to its starting position, and the treatment recommences at a different phase of tumour motion to 'fill in' the previously blocked beam projections. The gating process may be repeated until the plan dose is delivered (full gating), or halted after a certain number of passes, with the entire remaining dose delivered in a final pass without gating (partial gating). The feasibility of the full gating approach was first tested for sinusoidal target motion, through experimental measurements with film and computer simulation. The optimal gating parameters for full and partial gating methods were then determined for various fractionation schemes through computer simulation, using a patient respiratory waveform. For sinusoidal motion, the PTV dose deviations of -29 to 5% observed without gating were reduced to range from -1 to 3% for a single fraction, with a 4 pass full gating. For a patient waveform, partial gating required fewer passes than full gating for all fractionation schemes. For a single fraction, the maximum allowed residual motion was only 4 mm, requiring large numbers of passes for both full (12) and partial (7 + 1) gating methods. The number of required passes decreased significantly for 3 and 30 fractions, allowing residual motion up to 7 mm. Overall, the multi-pass gating technique was shown to be a

  8. Engineering a multimodal nerve conduit for repair of injured peripheral nerve

    Science.gov (United States)

    Quigley, A. F.; Bulluss, K. J.; Kyratzis, I. L. B.; Gilmore, K.; Mysore, T.; Schirmer, K. S. U.; Kennedy, E. L.; O'Shea, M.; Truong, Y. B.; Edwards, S. L.; Peeters, G.; Herwig, P.; Razal, J. M.; Campbell, T. E.; Lowes, K. N.; Higgins, M. J.; Moulton, S. E.; Murphy, M. A.; Cook, M. J.; Clark, G. M.; Wallace, G. G.; Kapsa, R. M. I.

    2013-02-01

    Injury to nerve tissue in the peripheral nervous system (PNS) results in long-term impairment of limb function, dysaesthesia and pain, often with associated psychological effects. Whilst minor injuries can be left to regenerate without intervention and short gaps up to 2 cm can be sutured, larger or more severe injuries commonly require autogenous nerve grafts harvested from elsewhere in the body (usually sensory nerves). Functional recovery is often suboptimal and associated with loss of sensation from the tissue innervated by the harvested nerve. The challenges that persist with nerve repair have resulted in development of nerve guides or conduits from non-neural biological tissues and various polymers to improve the prognosis for the repair of damaged nerves in the PNS. This study describes the design and fabrication of a multimodal controlled pore size nerve regeneration conduit using polylactic acid (PLA) and (PLA):poly(lactic-co-glycolic) acid (PLGA) fibers within a neurotrophin-enriched alginate hydrogel. The nerve repair conduit design consists of two types of PLGA fibers selected specifically for promotion of axonal outgrowth and Schwann cell growth (75:25 for axons; 85:15 for Schwann cells). These aligned fibers are contained within the lumen of a knitted PLA sheath coated with electrospun PLA nanofibers to control pore size. The PLGA guidance fibers within the nerve repair conduit lumen are supported within an alginate hydrogel impregnated with neurotrophic factors (NT-3 or BDNF with LIF, SMDF and MGF-1) to provide neuroprotection, stimulation of axonal growth and Schwann cell migration. The conduit was used to promote repair of transected sciatic nerve in rats over a period of 4 weeks. Over this period, it was observed that over-grooming and self-mutilation (autotomy) of the limb implanted with the conduit was significantly reduced in rats implanted with the full-configuration conduit compared to rats implanted with conduits containing only an alginate

  9. Expert Oracle GoldenGate

    CERN Document Server

    Prusinski, Ben; Chung, Richard

    2011-01-01

    Expert Oracle GoldenGate is a hands-on guide to creating and managing complex data replication environments using the latest in database replication technology from Oracle. GoldenGate is the future in replication technology from Oracle, and aims to be best-of-breed. GoldenGate supports homogeneous replication between Oracle databases. It supports heterogeneous replication involving other brands such as Microsoft SQL Server and IBM DB2 Universal Server. GoldenGate is high-speed, bidirectional, highly-parallelized, and makes only a light impact on the performance of databases involved in replica

  10. A novel optical gating method for laser gated imaging

    Science.gov (United States)

    Ginat, Ran; Schneider, Ron; Zohar, Eyal; Nesher, Ofer

    2013-06-01

    For the past 15 years, Elbit Systems is developing time-resolved active laser-gated imaging (LGI) systems for various applications. Traditional LGI systems are based on high sensitive gated sensors, synchronized to pulsed laser sources. Elbit propriety multi-pulse per frame method, which is being implemented in LGI systems, improves significantly the imaging quality. A significant characteristic of the LGI is its ability to penetrate a disturbing media, such as rain, haze and some fog types. Current LGI systems are based on image intensifier (II) sensors, limiting the system in spectral response, image quality, reliability and cost. A novel propriety optical gating module was developed in Elbit, untying the dependency of LGI system on II. The optical gating module is not bounded to the radiance wavelength and positioned between the system optics and the sensor. This optical gating method supports the use of conventional solid state sensors. By selecting the appropriate solid state sensor, the new LGI systems can operate at any desired wavelength. In this paper we present the new gating method characteristics, performance and its advantages over the II gating method. The use of the gated imaging systems is described in a variety of applications, including results from latest field experiments.

  11. Degradation properties of the electrostatic assembly PDLLA/CS/CHS nerve conduit

    Energy Technology Data Exchange (ETDEWEB)

    Xu Haixing [School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070 (China); Yan Yuhua; Wan Tao; Li Shipu, E-mail: yanyuhua8@126.co [Biomedical Materials and Engineering Research Center, Wuhan University of Technology, Wuhan 430070 (China)

    2009-08-15

    A poly(d,l-lactic acid)/chondroitin sulfate/chitosan (PDLLA/CS/CHS) nerve conduit for repairing nerve defects was prepared by electrostatic assembly and the thermally induced phase separation technique. The hydrophilic characteristics of the PDLLA/CS/CHS assembly nerve conduits were improved markedly. The degradation behavior of the nerve conduit with various assembly layers was evaluated by a pH change, weight loss rate and molecular weight change. The pH of the solution of the nerve conduit could be effectively adjusted by varying the layer numbers and overcoming the acidity-caused auto-acceleration of PDLLA; the nerve conduit can retain its integrity in a phosphate buffer solution after being degraded for 3 months. After such a conduit was implanted in the rat for 3 months, obvious degradation occurred, but the regenerated nerve was integrated and it grew successfully from the proximal to distal nerve stump. All these results implied that the degradation rate of the prepared conduit can adapt to the regeneration of the peripheral nerve, which might be a new derivative of PDLLA-based biodegradable materials for repairing nerve injuries without acidity-caused irritations and acidity-induced auto-accelerating degradation behavior as shown by PDLLA.

  12. Crystalline silicotitanate gate review analysis

    International Nuclear Information System (INIS)

    Schlahta, S.N.; Carreon, R.; Gentilucci, J.A.

    1997-11-01

    Crystalline silicotitanate (CST) is an ion-exchange method for removing radioactive cesium from tank waste to allow the separation of the waste into high- and low-level fractions. The CST, originally developed Sandia National Laboratories personnel in association with Union Oil Products Corporation, has both a high affinity and selectivity for sorbing cesium-137 from highly alkaline or acidic solutions. For several years now, the U.S. Department of Energy has funded work to investigate applying CST to large-scale removal of cesium-137 from radioactive tank wastes. In January 1997, an expert panel sponsored by the Tanks Focus Area met to review the current state of the technology and to determine whether it was ready for routine use. The review also sought to identify any technical issues that must be resolved or additional CST development that must occur before full implementation by end-users. The CST Gate Review Group concluded that sufficient work has been done to close developmental work on CST and turn the remaining site-specific tasks over to the users. This report documents the review group''s findings, issues, concerns, and recommendations as well as responses from the Tanks Focus Area expert staff to specific pretreatment and immobilization issues

  13. Hydrothermal Alteration of the Mt Unzen Conduit (Shimabara/Japan)

    Science.gov (United States)

    Yilmaz, T. I.; Mayer, K.; Hess, K. U.; Janots, E.; Gilg, H. A.; Dingwell, D. B.

    2016-12-01

    Investigations were carried out on hydrothermally altered coherent dacitic dykes samples from (USDP-4) drill core at Mt Unzen stratovolcano (Shimabara/Japan). XRF, XRD, EMPA, and C-O-isotope analysis led to insights concerning chemistry, mineralogy, and intensity of alteration as well as the origin of carbonate-precipitating fluids. Additionally a textural characterization of the occurring replacement features in the magma conduit zone was performed. The occurrence of the main secondary phases such as chlorite, pyrite, carbonates, and R1 (Reichweite parameter) illite-smectite indicate a weak to moderate propylitic to phyllic hydrothermal alteration. The dacitic samples of the dykes show different hydrothermal alteration features: (i) carbonate pseudomorphs after hornblende as well as core and zonal textures due to replacement of plagioclase by R1 illite-smectite, (ii) colloform banded fracture fillings and fillings in dissolution vugs, and (iii) chlorite and R1 illite-smectite in the groundmass. Carbonates in fractures comprise iron-rich dolomite solid solutions ("ankerite") and calcite. Isotopic values of d13Cvpdb = -4.59 ± 0.6‰ and d18Ovpdb = -21.73 ± 0.5‰ indicate a hydrothermal-magmatic origin for the carbonate formation. The chlorite-carbonate-pyrite index (CCPI) and the Ishikawa alteration index (AI), applied to the investigated samples show significant differences (CCPI=52.7-57.8; AI=36.1-40.6) indicating their different degree of alteration. According to Nakada et al., 2005, the C13 to C16 dykes represent the feeder dyke from the latest eruption (1991-1995) whereas C8 represents an earlier dyke feeder dyke from an older eruption. Weakest conduit alteration, which was obtained in samples C16-1-5 and C13-2-5, correlates with the alteration degree of the pristine dome rocks. Highest CCPI value was determined for sample C14-1-5 and the highest AI value was determined for sample C15-2-6. The degrees of alteration do not indicate highest alteration of the

  14. Reverse saphenous conduit flap in small animals: Clinical applications and outcomes

    Directory of Open Access Journals (Sweden)

    Ross C. Elliott

    2014-08-01

    Full Text Available Due to the lack of skin elasticity defects of the distal hind limb can be a challenge to close. This article assesses a well-described, but completely under-used technique for closure of wounds on the distal tarsus. The technique was used with good success in six cases presenting to the Bryanston Veterinary Hospital with a wide range of underlying pathology ranging from trauma to neoplastic disease of the tarsus. All six cases were treated with a reverse saphenous conduit flap and two of them underwent radiation therapy with no adverse side effects. All cases showed excellent results with a very low degree of flap necrosis that never exceeded 15% of the total flap area. This skin flap provides an excellent treatment method that is reliable in closure of defects of the distal tarsus with few adverse effects. To the author’s knowledge there has been only one previously published report on the clinical use of this type of skin flap,even though the flap is well described in most texts.

  15. Impact of sea level rise on tide gate function.

    Science.gov (United States)

    Walsh, Sean; Miskewitz, Robert

    2013-01-01

    Sea level rise resulting from climate change and land subsidence is expected to severely impact the duration and associated damage resulting from flooding events in tidal communities. These communities must continuously invest resources for the maintenance of existing structures and installation of new flood prevention infrastructure. Tide gates are a common flood prevention structure for low-lying communities in the tidal zone. Tide gates close during incoming tides to prevent inundation from downstream water propagating inland and open during outgoing tides to drain upland areas. Higher downstream mean sea level elevations reduce the effectiveness of tide gates by impacting the hydraulics of the system. This project developed a HEC-RAS and HEC-HMS model of an existing tide gate structure and its upland drainage area in the New Jersey Meadowlands to simulate the impact of rising mean sea level elevations on the tide gate's ability to prevent upstream flooding. Model predictions indicate that sea level rise will reduce the tide gate effectiveness resulting in longer lasting and deeper flood events. The results indicate that there is a critical point in the sea level elevation for this local area, beyond which flooding scenarios become dramatically worse and would have a significantly negative impact on the standard of living and ability to do business in one of the most densely populated areas of America.

  16. Generic two-qubit photonic gates implemented by number-resolving photodetection

    International Nuclear Information System (INIS)

    Uskov, Dmitry B.; Smith, A. Matthew; Kaplan, Lev

    2010-01-01

    We combine numerical optimization techniques [Uskov et al., Phys. Rev. A 79, 042326 (2009)] with symmetries of the Weyl chamber to obtain optimal implementations of generic linear-optical Knill-Laflamme-Milburn-type two-qubit entangling gates. We find that while any two-qubit controlled-U gate, including controlled-NOT (CNOT) and controlled-sign gates, can be implemented using only two ancilla resources with a success probability S>0.05, a generic SU(4) operation requires three unentangled ancilla photons, with success S>0.0063. Specifically, we obtain a maximal success probability close to 0.0072 for the B gate. We show that single-shot implementation of a generic SU(4) gate offers more than an order of magnitude increase in the success probability and a two-fold reduction in overhead ancilla resources compared to standard triple-CNOT and double-B gate decompositions.

  17. Penn State DOE GATE Program

    Energy Technology Data Exchange (ETDEWEB)

    Anstrom, Joel

    2012-08-31

    The Graduate Automotive Technology Education (GATE) Program at The Pennsylvania State University (Penn State) was established in October 1998 pursuant to an award from the U.S. Department of Energy (U.S. DOE). The focus area of the Penn State GATE Program is advanced energy storage systems for electric and hybrid vehicles.

  18. Piezoconductivity of gated suspended graphene

    NARCIS (Netherlands)

    Medvedyeva, M.V.; Blanter, Y.M.

    2011-01-01

    We investigate the conductivity of graphene sheet deformed over a gate. The effect of the deformation on the conductivity is twofold: The lattice distortion can be represented as pseudovector potential in the Dirac equation formalism, whereas the gate causes inhomogeneous density redistribution. We

  19. Conduits to care: call lights and patients’ perceptions of communication

    Science.gov (United States)

    Montie, Mary; Shuman, Clayton; Galinato, Jose; Patak, Lance; Anderson, Christine A; Titler, Marita G

    2017-01-01

    Background Call light systems remain the primary means of hospitalized patients to initiate communication with their health care providers. Although there is vast amounts of literature discussing patient communication with their health care providers, few studies have explored patients’ perceptions concerning call light use and communication. The specific aim of this study was to solicit patients’ perceptions regarding their call light use and communication with nursing staff. Methods Patients invited to this study met the following inclusion criteria: proficient in English, been hospitalized for at least 24 hours, aged ≥21 years, and able to communicate verbally (eg, not intubated). Thirty participants provided written informed consent, were enrolled in the study, and completed interviews. Results Using qualitative descriptive methods, five major themes emerged from patients’ perceptions (namely; establishing connectivity, participant safety concerns, no separation: health care and the call light device, issues with the current call light, and participants’ perceptions of “nurse work”). Multiple minor themes supported these major themes. Data analysis utilized the constant comparative methods of Glaser and Strauss. Discussion Findings from this study extend the knowledge of patients’ understanding of not only why inconsistencies occur between the call light and their nurses, but also why the call light is more than merely a device to initiate communication; rather, it is a direct conduit to their health care and its delivery. PMID:29075125

  20. Conduits to care: call lights and patients' perceptions of communication.

    Science.gov (United States)

    Montie, Mary; Shuman, Clayton; Galinato, Jose; Patak, Lance; Anderson, Christine A; Titler, Marita G

    2017-01-01

    Call light systems remain the primary means of hospitalized patients to initiate communication with their health care providers. Although there is vast amounts of literature discussing patient communication with their health care providers, few studies have explored patients' perceptions concerning call light use and communication. The specific aim of this study was to solicit patients' perceptions regarding their call light use and communication with nursing staff. Patients invited to this study met the following inclusion criteria: proficient in English, been hospitalized for at least 24 hours, aged ≥21 years, and able to communicate verbally (eg, not intubated). Thirty participants provided written informed consent, were enrolled in the study, and completed interviews. Using qualitative descriptive methods, five major themes emerged from patients' perceptions (namely; establishing connectivity, participant safety concerns, no separation: health care and the call light device, issues with the current call light, and participants' perceptions of "nurse work"). Multiple minor themes supported these major themes. Data analysis utilized the constant comparative methods of Glaser and Strauss. Findings from this study extend the knowledge of patients' understanding of not only why inconsistencies occur between the call light and their nurses, but also why the call light is more than merely a device to initiate communication; rather, it is a direct conduit to their health care and its delivery.

  1. Relaxation of microparticles exposed to hydrodynamic forces in microfluidic conduits.

    Science.gov (United States)

    Janča, Josef; Halabalová, Věra; Polášek, Vladimír; Vašina, Martin; Menshikova, Anastasia Yu

    2011-02-01

    The behavior of microparticles exposed to gravitational and lift forces and to the velocity gradient in flow velocity profile formed in microfluidic conduits is studied from the viewpoint of the transient period (the relaxation) between the moment at which a particle starts to be transported by the hydrodynamic flow and the time at which it reaches an equilibrium position, characterized by a balance of all active forces. The theoretical model allowing the calculation of the relaxation time is proposed. The numerical calculus based on the proposed model is compared with the experimental data obtained under different experimental conditions, namely, for different lengths of microfluidic channels, different average linear velocities of the carrier liquid, and different sizes and densities of the particles used in the study. The results are important for the optimization of microfluidic separation units such as microthermal field-flow fractionation channels in which the separation or manipulation of the microparticles of various origin, synthetic, natural, biological, etc., is performed under similar experimental conditions but by applying an additional thermodynamic force.

  2. On photonic controlled phase gates

    International Nuclear Information System (INIS)

    Kieling, K; Eisert, J; O'Brien, J L

    2010-01-01

    As primitives for entanglement generation, controlled phase gates have a central role in quantum computing. Especially in ideas realizing instances of quantum computation in linear optical gate arrays, a closer look can be rewarding. In such architectures, all effective nonlinearities are induced by measurements. Hence the probability of success is a crucial parameter of such quantum gates. In this paper, we discuss this question for controlled phase gates that implement an arbitrary phase with one and two control qubits. Within the class of post-selected gates in dual-rail encoding with vacuum ancillas, we identify the optimal success probabilities. We construct networks that allow for implementation using current experimental capabilities in detail. The methods employed here appear specifically useful with the advent of integrated linear optical circuits, providing stable interferometers on monolithic structures.

  3. GATE: Improving the computational efficiency

    International Nuclear Information System (INIS)

    Staelens, S.; De Beenhouwer, J.; Kruecker, D.; Maigne, L.; Rannou, F.; Ferrer, L.; D'Asseler, Y.; Buvat, I.; Lemahieu, I.

    2006-01-01

    GATE is a software dedicated to Monte Carlo simulations in Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET). An important disadvantage of those simulations is the fundamental burden of computation time. This manuscript describes three different techniques in order to improve the efficiency of those simulations. Firstly, the implementation of variance reduction techniques (VRTs), more specifically the incorporation of geometrical importance sampling, is discussed. After this, the newly designed cluster version of the GATE software is described. The experiments have shown that GATE simulations scale very well on a cluster of homogeneous computers. Finally, an elaboration on the deployment of GATE on the Enabling Grids for E-Science in Europe (EGEE) grid will conclude the description of efficiency enhancement efforts. The three aforementioned methods improve the efficiency of GATE to a large extent and make realistic patient-specific overnight Monte Carlo simulations achievable

  4. Large-area irradiated low-level laser effect in a biodegradable nerve guide conduit on neural regeneration of peripheral nerve injury in rats.

    Science.gov (United States)

    Shen, Chiung-Chyi; Yang, Yi-Chin; Liu, Bai-Shuan

    2011-08-01

    This study used a biodegradable composite containing genipin-cross-linked gelatin annexed with β-tricalcium phosphate ceramic particles (genipin-gelatin-tricalcium phosphate, GGT), developed in a previous study, as a nerve guide conduit. The aim of this study was to analyse the influence of a large-area irradiated aluminium-gallium-indium phosphide (AlGaInP) diode laser (660 nm) on the neural regeneration of the transected sciatic nerve after bridging the GGT nerve guide conduit in rats. The animals were divided into two groups: group 1 comprised sham-irradiated controls and group 2 rats underwent low-level laser (LLL) therapy. A compact multi-cluster laser system with 20 AlGaInP laser diodes (output power, 50mW) was applied transcutaneously to the injured peripheral nerve immediately after closing the wound, which was repeated daily for 5 min for 21 consecutive days. Eight weeks after implantation, walking track analysis showed a significantly higher sciatic function index (SFI) score (Pguide conduit in rats. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Gated equilibrium bloodpool scintigraphy

    International Nuclear Information System (INIS)

    Reinders Folmer, S.C.C.

    1981-01-01

    This thesis deals with the clinical applications of gated equilibrium bloodpool scintigraphy, performed with either a gamma camera or a portable detector system, the nuclear stethoscope. The main goal has been to define the value and limitations of noninvasive measurements of left ventricular ejection fraction as a parameter of cardiac performance in various disease states, both for diagnostic purposes as well as during follow-up after medical or surgical intervention. Secondly, it was attempted to extend the use of the equilibrium bloodpool techniques beyond the calculation of ejection fraction alone by considering the feasibility to determine ventricular volumes and by including the possibility of quantifying valvular regurgitation. In both cases, it has been tried to broaden the perspective of the observations by comparing them with results of other, invasive and non-invasive, procedures, in particular cardiac catheterization, M-mode echocardiography and myocardial perfusion scintigraphy. (Auth.)

  6. Scientific Results of Conduit Drilling in the Unzen Scientific Drilling Project (USDP

    Directory of Open Access Journals (Sweden)

    Kozo Uto

    2005-09-01

    Full Text Available Abstract Directional drilling at Unzen Volcano in Japan duringmid of 2004 penetrated the magma conduit and successfullyrecovered samples of the lava dike that is believed to havefed the 1991–1995 eruption. The dike was sampled about1.3 km below the volcano’s summit vent and is intrudedinto a broader conduit zone that is 0.5 km wide. This zoneconsists of multiple older lava dikes and pyroclastic veinsand has cooled to less than 200˚C. The lava dike sample wasunexpectedly altered, suggesting that circulation of hydrothermalfluids rapidly cools the conduit region of even veryactive volcanoes. It is likely that seismic signals monitoredprior to emergence of the lava dome reflected fracturing ofthe country rocks, caused by veining as volatiles escapedpredominantly upward, not outward, from the rising magma.Geophysical and geological investigation of cuttings andcore samples from the conduit and of bore-hole logging datacontinues.

  7. Transcatheter Pulmonary Valve Replacement for Right Ventricular Outflow Tract Conduit Dysfunction After the Ross Procedure

    DEFF Research Database (Denmark)

    Gillespie, Matthew J; McElhinney, Doff B; Kreutzer, Jacqueline

    2015-01-01

    BACKGROUND: Right ventricular outflow tract (RVOT) conduit dysfunction is a limitation of the Ross procedure. Transcatheter pulmonary valve replacement (TPVR) could alter the impact of conduit dysfunction and the risk-benefit balance for the Ross procedure. METHODS: Retrospective review of databa......BACKGROUND: Right ventricular outflow tract (RVOT) conduit dysfunction is a limitation of the Ross procedure. Transcatheter pulmonary valve replacement (TPVR) could alter the impact of conduit dysfunction and the risk-benefit balance for the Ross procedure. METHODS: Retrospective review....... Of these, 56 (84%) received a Melody valve; in 5 of the 11 patients who did not, the implant was aborted due to concern for coronary artery compression, and 1 implanted patient required emergent surgery for left coronary compression. The RVOT gradient decreased from a median 38 mm Hg to 13.5 mm Hg (p

  8. Investigation of entrance length in circular and noncircular conduits by computational fluid dynamics simulation

    Directory of Open Access Journals (Sweden)

    Pimpun Tongpun

    2014-08-01

    Full Text Available This study estimated entrance length of circular and noncircular conduits, including circle, triangle, square and hexagon cross-sectional conduit, by using computational fluid dynamics (CFD. For simulation condition, the length of noncircular conduit was 10 m and the hydraulic diameter was 0.2 m. The laminar flow with Reynolds number of 500 and turbulent flow with Reynolds number of 50,000 were applied to investigate water flow in conduits. The governing equations were solved iteratively by using ANSYS FLUENT 14.0. For turbulent flow simulation, standard k-epsilon and RNG k-epsilon model were employed to simulate turbulence. The preliminary results were validated by comparison with theoretical data. At first, grid independency was evaluated to optimize the model. Norm* was employed to investigate the entrance length, which is related to velocity. The simulated results revealed that the entrance length for laminar flow was longer than turbulent flow.

  9. In vivo visualization of microneedle conduits in human skin using laser scanning microscopy

    International Nuclear Information System (INIS)

    Bal, S; Kruithof, A C; Bouwstra, J; Liebl, H; Tomerius, M; Lademann, J; Meinke, M

    2010-01-01

    Solid microneedles enhance the penetration of drugs into the viable skin but little is known about the geometry of the conduits in vivo. Therefore, laser scanning microscopy was used to visualize the conduits of a microneedle system with needles at a length of 300 μm in 6 healthy subjects over a period of time. The model drug, a fluorescent dye was applied before and after piercing. Laser scanning microscopy was evaluated as being an excellent method to monitor the geometry and closure of the conduits over time. The used microneedle system was evaluated as suitable to enhance the transport of model drugs into the viable epidermis without bleeding and a short closure time of the conduits at the skin surface

  10. In vivo visualization of microneedle conduits in human skin using laser scanning microscopy

    Science.gov (United States)

    Bal, S.; Kruithof, A. C.; Liebl, H.; Tomerius, M.; Bouwstra, J.; Lademann, J.; Meinke, M.

    2010-03-01

    Solid microneedles enhance the penetration of drugs into the viable skin but little is known about the geometry of the conduits in vivo. Therefore, laser scanning microscopy was used to visualize the conduits of a microneedle system with needles at a length of 300 μm in 6 healthy subjects over a period of time. The model drug, a fluorescent dye was applied before and after piercing. Laser scanning microscopy was evaluated as being an excellent method to monitor the geometry and closure of the conduits over time. The used microneedle system was evaluated as suitable to enhance the transport of model drugs into the viable epidermis without bleeding and a short closure time of the conduits at the skin surface.

  11. Imaging of ventilation/perfusion ratio by gated regional spirometry

    International Nuclear Information System (INIS)

    Touya, J.J.; Jones, J.P.; Price, R.R.; Patton, J.A.; Erickson, J.J.; Rollo, F.D.

    1981-01-01

    Gated 133 Xe images of patients rebreathing into a closed system can provide images of the distribution of lung volumes, ventilation and specific ventilation. These have been shown to be accurate, precise, and do not require unusually sophisticated equipment or skills. A mathematical transformation is used to correct the images for lung movement, which does not alter the total number of counts in the image. Perfusion images are gated to remove motion blurring but not transformed. Ventilation/perfusion images showing the distribution of V/Q ratio are then generated from the individual ventilation and perfusion images. (author)

  12. Silk fibroin enhances peripheral nerve regeneration by improving vascularization within nerve conduits.

    Science.gov (United States)

    Wang, Chunyang; Jia, Yachao; Yang, Weichao; Zhang, Cheng; Zhang, Kuihua; Chai, Yimin

    2018-07-01

    Silk fibroin (SF)-based nerve conduits have been widely used to bridge peripheral nerve defects. Our previous study showed that nerve regeneration in a SF-blended poly (l-lactide-co-ɛ-caprolactone) [P(LLA-CL)] nerve conduit is better than that in a P(LLA-CL) conduit. However, the involved mechanisms remain unclarified. Because angiogenesis within a nerve conduit plays an important role in nerve regeneration, vascularization of SF/P(LLA-CL) and P(LLA-CL) conduits was compared both in vitro and in vivo. In the present study, we observed that SF/P(LLA-CL) nanofibers significantly promoted fibroblast proliferation, and vascular endothelial growth factor secreted by fibroblasts seeded in SF/P(LLA-CL) nanofibers was more than seven-fold higher than that in P(LLA-CL) nanofibers. Conditioned medium of fibroblasts in the SF/P(LLA-CL) group stimulated more human umbilical vein endothelial cells (HUVEC) to form capillary-like networks and promoted faster HUVEC migration. The two kinds of nerve conduits were used to bridge 10-mm-length nerve defects in rats. At 3 weeks of reparation, the blood vessel area in the SF/P(LLA-CL) group was significantly larger than that in the P(LLA-CL) group. More regenerated axons and Schwann cells were also observed in the SF/P(LLA-CL) group, which was consistent with the results of blood vessels. Collectively, our data revealed that the SF/P(LLA-CL) nerve conduit enhances peripheral nerve regeneration by improving angiogenesis within the conduit. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2070-2077, 2018. © 2018 Wiley Periodicals, Inc.

  13. Ureteric catheterization via an ileal conduit: technique and retrieval of a JJ stent.

    Science.gov (United States)

    Wah, T M; Kellett, M J

    2004-11-01

    Retrograde ureteric catheterization of a patient with an ileal conduit is difficult, because guide wires and catheters coil in the conduit. A modified loopogram, using a Foley catheter as a fulcrum through which catheters can be advanced to the ureteric anastomosis, is described. This technique was used to remove a JJ stent, which had been inserted previously across a stricture in one ureter, the stent crossing from one kidney to the other.

  14. Long distance seawater intrusion through a karst conduit network in the Woodville Karst Plain, Florida

    OpenAIRE

    Zexuan Xu; Seth Willis Bassett; Bill Hu; Scott Barrett Dyer

    2016-01-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electrical conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and travel...

  15. Generation of Complex Karstic Conduit Networks with a Hydro-chemical Model

    Science.gov (United States)

    De Rooij, R.; Graham, W. D.

    2016-12-01

    The discrete-continuum approach is very well suited to simulate flow and solute transport within karst aquifers. Using this approach, discrete one-dimensional conduits are embedded within a three-dimensional continuum representative of the porous limestone matrix. Typically, however, little is known about the geometry of the karstic conduit network. As such the discrete-continuum approach is rarely used for practical applications. It may be argued, however, that the uncertainty associated with the geometry of the network could be handled by modeling an ensemble of possible karst conduit networks within a stochastic framework. We propose to generate stochastically realistic karst conduit networks by simulating the widening of conduits as caused by the dissolution of limestone over geological relevant timescales. We illustrate that advanced numerical techniques permit to solve the non-linear and coupled hydro-chemical processes efficiently, such that relatively large and complex networks can be generated in acceptable time frames. Instead of specifying flow boundary conditions on conduit cells to recharge the network as is typically done in classical speleogenesis models, we specify an effective rainfall rate over the land surface and let model physics determine the amount of water entering the network. This is advantageous since the amount of water entering the network is extremely difficult to reconstruct, whereas the effective rainfall rate may be quantified using paleoclimatic data. Furthermore, we show that poorly known flow conditions may be constrained by requiring a realistic flow field. Using our speleogenesis model we have investigated factors that influence the geometry of simulated conduit networks. We illustrate that our model generates typical branchwork, network and anastomotic conduit systems. Flow, solute transport and water ages in karst aquifers are simulated using a few illustrative networks.

  16. Voltage-gated lipid ion channels

    DEFF Research Database (Denmark)

    Blicher, Andreas; Heimburg, Thomas Rainer

    2013-01-01

    Synthetic lipid membranes can display channel-like ion conduction events even in the absence of proteins. We show here that these events are voltage-gated with a quadratic voltage dependence as expected from electrostatic theory of capacitors. To this end, we recorded channel traces and current...... histograms in patch-experiments on lipid membranes. We derived a theoretical current-voltage relationship for pores in lipid membranes that describes the experimental data very well when assuming an asymmetric membrane. We determined the equilibrium constant between closed and open state and the open...... probability as a function of voltage. The voltage-dependence of the lipid pores is found comparable to that of protein channels. Lifetime distributions of open and closed events indicate that the channel open distribution does not follow exponential statistics but rather power law behavior for long open times...

  17. Ecoulements intermittents de gaz et de liquide en conduite verticale Intermittent Gas and Liquid Flows in a Vertical Pipe.

    Directory of Open Access Journals (Sweden)

    Line A.

    2006-11-01

    Full Text Available Le modèle présenté ici permet la pré-détermination du gradient de pression, du taux global de gaz, et de grandeurs caractéristiques de l'intermittence, dans un écoulement à poches et bouchons en conduite verticale. L'écriture des lois de conservation en moyenne phasique conditionnelle conduit à la définition d'une cellule moyenne équivalente. La fermeture du modèle est assurée par des lois de contrainte de cisaillement film-paroi, film-poche, bouchon-paroi, par une loi d'arrachage du gaz au culot de la poche, une loi de glissement du gaz dans les bouchons et par une loi de la vitesse moyenne de propagation des fronts de poches. Le calibrage et la qualification du modèle s'appuient sur deux banques de données, dont l'une a été obtenue avec des fluides pétroliers dans des conditions proches des situations industrielles (boucle diphasique de Boussens. The model described here can be used to predetermine the pressure gradient, the overall gas rate and the characteristic intermittence magnitudes in pocket and slug flow in a vertical pipe. The way governing equations in the conditional phase average are written defines an equivalent average cell. The model is closed by film/wall, film/pocket and slug/wall shear-stress laws, by a pulloff law for the gas at the bottom of the pocket, a slippage law for the gas in the slugs, and a mean propagation velocity law for the pocket fronts. The calibration and qualification of the model are based on two data banks, one of which contains data on petroleum fluids under conditions close to industrial situations (two-phase loop at Boussens.

  18. MR and CT imaging of pulmonary valved conduits in children and adolescents: normal appearance and complications

    Energy Technology Data Exchange (ETDEWEB)

    Tenisch, Estelle V.; Alamo, Leonor T.; Gudinchet, Francois [Lausanne University Hospital, Department of Medical Imaging, Lausanne (Switzerland); Sekarski, Nicole [Lausanne University Hospital, Department of Pediatrics, Lausanne (Switzerland); Hurni, Michel [Lausanne University Hospital, Department of Cardiovascular Surgery, Lausanne (Switzerland)

    2014-12-15

    The Contegra registered is a conduit made from the bovine jugular vein and then interposed between the right ventricle and the pulmonary artery. It is used for cardiac malformations in the reconstruction of right ventricular outflow tract. To describe both normal and pathological appearances of the Contegra registered in radiological imaging, to describe imaging of complications and to define the role of CT and MRI in postoperative follow-up. Forty-three examinations of 24 patients (17 boys and 7 girls; mean age: 10.8 years old) with Contegra registered conduits were reviewed. Anatomical description and measurements of the conduits were performed. Pathological items examined included stenosis, dilatation, plicature or twist, thrombus or vegetations, calcifications and valvular regurgitation. Findings were correlated to the echographic gradient through the conduit when available. CT and MR work-up showed Contegra registered stenosis (n = 12), dilatation (n = 9) and plicature or twist (n = 7). CT displayed thrombus or vegetations in the Contegra registered in three clinically infected patients. Calcifications of the conduit were present at CT in 12 patients and valvular regurgitation in three patients. The comparison between CT and/or MR results showed a good correlation between the echographic gradient and the presence of stenosis in the Contegra registered. CT and MR bring additional information about permeability and postoperative anatomy especially when echocardiography is inconclusive. Both techniques depict the normal appearance of the conduit, and allow comparison and precise evaluation of changes in the postoperative follow-up. (orig.)

  19. In vitro evaluation of carbon-nanotube-reinforced bioprintable vascular conduits

    International Nuclear Information System (INIS)

    Dolati, Farzaneh; Yu, Yin; Zhang, Yahui; Ozbolat, Ibrahim T; Jesus, Aribet M De; Sander, Edward A

    2014-01-01

    Vascularization of thick engineered tissue and organ constructs like the heart, liver, pancreas or kidney remains a major challenge in tissue engineering. Vascularization is needed to supply oxygen and nutrients and remove waste in living tissues and organs through a network that should possess high perfusion ability and significant mechanical strength and elasticity. In this paper, we introduce a fabrication process to print vascular conduits directly, where conduits were reinforced with carbon nanotubes (CNTs) to enhance their mechanical properties and bioprintability. In vitro evaluation of printed conduits encapsulated in human coronary artery smooth muscle cells was performed to characterize the effects of CNT reinforcement on the mechanical, perfusion and biological performance of the conduits. Perfusion and permeability, cell viability, extracellular matrix formation and tissue histology were assessed and discussed, and it was concluded that CNT-reinforced vascular conduits provided a foundation for mechanically appealing constructs where CNTs could be replaced with natural protein nanofibers for further integration of these conduits in large-scale tissue fabrication. (paper)

  20. A biosynthetic nerve guide conduit based on silk/SWNT/fibronectin nanocomposite for peripheral nerve regeneration.

    Directory of Open Access Journals (Sweden)

    Fatemeh Mottaghitalab

    Full Text Available As a contribution to the functionality of nerve guide conduits (NGCs in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts.

  1. The Himalayas: barrier and conduit for gene flow.

    Science.gov (United States)

    Gayden, Tenzin; Perez, Annabel; Persad, Patrice J; Bukhari, Areej; Chennakrishnaiah, Shilpa; Simms, Tanya; Maloney, Trisha; Rodriguez, Kristina; Herrera, Rene J

    2013-06-01

    The Himalayan mountain range is strategically located at the crossroads of the major cultural centers in Asia, the Middle East and Europe. Although previous Y-chromosome studies indicate that the Himalayas served as a natural barrier for gene flow from the south to the Tibetan plateau, this region is believed to have played an important role as a corridor for human migrations between East and West Eurasia along the ancient Silk Road. To evaluate the effects of the Himalayan mountain range in shaping the maternal lineages of populations residing on either side of the cordillera, we analyzed mitochondrial DNA variation in 344 samples from three Nepalese collections (Newar, Kathmandu and Tamang) and a general population of Tibet. Our results revealed a predominantly East Asian-specific component in Tibet and Tamang, whereas Newar and Kathmandu are both characterized by a combination of East and South Central Asian lineages. Interestingly, Newar and Kathmandu harbor several deep-rooted Indian lineages, including M2, R5, and U2, whose coalescent times from this study (U2, >40 kya) and previous reports (M2 and R5, >50 kya) suggest that Nepal was inhabited during the initial peopling of South Central Asia. Comparisons with our previous Y-chromosome data indicate sex-biased migrations in Tamang and a founder effect and/or genetic drift in Tamang and Newar. Altogether, our results confirm that while the Himalayas acted as a geographic barrier for human movement from the Indian subcontinent to the Tibetan highland, it also served as a conduit for gene flow between Central and East Asia. Copyright © 2013 Wiley Periodicals, Inc.

  2. Current distribution in Cable-In-Conduit Conductors

    International Nuclear Information System (INIS)

    Ferri, M.A.

    1994-05-01

    A numerical study of the current distribution in Cable-In-Conduit Conductors (CICC's) experiencing linearly ramping transport currents and transverse magnetic fields was conducted for both infinitely long, periodic cables and finite length cables terminated in low resistance joints. The goal of the study was to gain insight into the phenomenon known as Ramp Rate Limitation, an as yet unexplained correspondence between maximum attainable current and the ramp time taken to reach that current in CICC superconducting magnets. A discrete geometric model of a 27 strand multiply twisted CICC was developed to effectively represent the flux linkages, mutual inductances, and resistive contact points between the strands of an experimentally tested cable. The results of the numerical study showed that for fully periodic cables, the current imbalances due to ramping magnetic fields and ramping transport currents are negligible in the range of experimentally explored operating conditions. For finite length, joint terminated cables, however, significant imbalances can exist. Unfortunately, quantitative results are limited by a lack of knowledge of the transverse resistance between strands in the joints. Nonetheless, general results are presented showing the dependency of the imbalance on cable length, ramp time, and joint resistance for both ramping transverse magnet fields and ramping transport currents. At the conclusion of the study, it is suggested that calculated current imbalances in a finite length cable could cause certain strands to prematurely ''quench'' -- become non-superconducting --thus leading to an instability for the entire cable. This numerically predicted ''current imbalance instability'' is compared to the experimentally observed Ramp Rate Limitation for the 27 strand CICC sample

  3. Conduits to care: call lights and patients’ perceptions of communication

    Directory of Open Access Journals (Sweden)

    Montie M

    2017-09-01

    Full Text Available Mary Montie,1 Clayton Shuman,1 Jose Galinato,1 Lance Patak,2 Christine A Anderson,1 Marita G Titler1 1Department of Systems, Populations, and Leadership, School of Nursing, University of Michigan, Ann Arbor, MI, 2Department of Anesthesiology and Pain Medicine, Seattle Children’s Hospital, Seattle, WA, USA Background: Call light systems remain the primary means of hospitalized patients to initiate communication with their health care providers. Although there is vast amounts of literature discussing patient communication with their health care providers, few studies have explored patients’ perceptions concerning call light use and communication. The specific aim of this study was to solicit patients’ perceptions regarding their call light use and communication with nursing staff. Methods: Patients invited to this study met the following inclusion criteria: proficient in English, been hospitalized for at least 24 hours, aged ≥21 years, and able to communicate verbally (eg, not intubated. Thirty participants provided written informed consent, were enrolled in the study, and completed interviews. Results: Using qualitative descriptive methods, five major themes emerged from patients’ perceptions (namely; establishing connectivity, participant safety concerns, no separation: health care and the call light device, issues with the current call light, and participants’ perceptions of “nurse work”. Multiple minor themes supported these major themes. Data analysis utilized the constant comparative methods of Glaser and Strauss. Discussion: Findings from this study extend the knowledge of patients’ understanding of not only why inconsistencies occur between the call light and their nurses, but also why the call light is more than merely a device to initiate communication; rather, it is a direct conduit to their health care and its delivery. Keywords: nurse–patient communication, medical technology, quality of care, qualitative research

  4. Photon-gated spin transistor

    OpenAIRE

    Li, Fan; Song, Cheng; Cui, Bin; Peng, Jingjing; Gu, Youdi; Wang, Guangyue; Pan, Feng

    2017-01-01

    Spin-polarized field-effect transistor (spin-FET), where a dielectric layer is generally employed for the electrical gating as the traditional FET, stands out as a seminal spintronic device under the miniaturization trend of electronics. It would be fundamentally transformative if optical gating was used for spin-FET. We report a new type of spin-polarized field-effect transistor (spin-FET) with optical gating, which is fabricated by partial exposure of the (La,Sr)MnO3 channel to light-emitti...

  5. A polymer foam conduit seeded with Schwann cells promotes guided peripheral nerve regeneration.

    Science.gov (United States)

    Hadlock, T; Sundback, C; Hunter, D; Cheney, M; Vacanti, J P

    2000-04-01

    Alternatives to autografts have long been sought for use in bridging neural gaps. Many entubulation materials have been studied, although with generally disappointing results in comparison with autografts. The purpose of this study was to design a more effective neural guidance conduit, to introduce Schwann cells into the conduit, and to determine regenerative capability through it in an in vivo model. A novel, fully biodegradable polymer conduit was designed and fabricated for use in peripheral nerve repair, which approximates the macro- and microarchitecture of native peripheral nerves. It comprised a series of longitudinally aligned channels, with diameters ranging from 60 to 550 microns. The lumenal surfaces promoted the adherence of Schwann cells, whose presence is known to play a key role in nerve regeneration. This unique channel architecture increased the surface area available for Schwann cell adherence up to five-fold over that available through a simple hollow conduit. The conduit was composed of a high-molecular-weight copolymer of lactic and glycolic acids (PLGA) (MW 130,000) in an 85:15 monomer ratio. A novel foam-processing technique, employing low-pressure injection molding, was used to create highly porous conduits (approximately 90% pore volume) with continuous longitudinal channels. Using this technique, conduits were constructed containing 1, 5, 16, 45, or more longitudinally aligned channels. Prior to cellular seeding of these conduits, the foams were prewet with 50% ethanol, flushed with physiologic saline, and coated with laminin solution (10 microg/mL). A Schwann cell suspension was dynamically introduced into these processed foams at a concentration of 5 X 10(5) cells/mL, using a simple bioreactor flow loop. In vivo regeneration studies were carried out in which cell-laden five-channel polymer conduits (individual channel ID 500 microm, total conduit OD 2.3 mm) were implanted across a 7-mm gap in the rat sciatic nerve (n = 4), and midgraft

  6. Transient Air-Water Flow and Air Demand following an Opening Outlet Gate

    Directory of Open Access Journals (Sweden)

    James Yang

    2018-01-01

    Full Text Available In Sweden, the dam-safety guidelines call for an overhaul of many existing bottom outlets. During the opening of an outlet gate, understanding the transient air-water flow is essential for its safe operation, especially under submerged tailwater conditions. Three-dimensional CFD simulations are undertaken to examine air-water flow behaviors at both free and submerged outflows. The gate, hoisted by wire ropes and powered by AC, opens at a constant speed. A mesh is adapted to follow the gate movement. At the free outflow, the CFD simulations and model tests agree well in terms of outlet discharge capacity. Larger air vents lead to more air supply; the increment becomes, however, limited if the vent area is larger than 10 m2. At the submerged outflow, a hydraulic jump builds up in the conduit when the gate reaches approximately 45% of its full opening. The discharge is affected by the tailwater and slightly by the flow with the hydraulic jump. The flow features strong turbulent mixing of air and water, with build-up and break-up of air pockets and collisions of defragmented water bodies. The air demand rate is several times as much as required by steady-state hydraulic jump with free surface.

  7. Reversible logic gates on Physarum Polycephalum

    International Nuclear Information System (INIS)

    Schumann, Andrew

    2015-01-01

    In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum

  8. Demonstration of a Quantum Nondemolition Sum Gate

    DEFF Research Database (Denmark)

    Yoshikawa, J.; Miwa, Y.; Huck, Alexander

    2008-01-01

    The sum gate is the canonical two-mode gate for universal quantum computation based on continuous quantum variables. It represents the natural analogue to a qubit C-NOT gate. In addition, the continuous-variable gate describes a quantum nondemolition (QND) interaction between the quadrature...

  9. Gating of human ClC-2 chloride channels and regulation by carboxy-terminal domains.

    Science.gov (United States)

    Garcia-Olivares, Jennie; Alekov, Alexi; Boroumand, Mohammad Reza; Begemann, Birgit; Hidalgo, Patricia; Fahlke, Christoph

    2008-11-15

    Eukaryotic ClC channels are dimeric proteins with each subunit forming an individual protopore. Single protopores are gated by a fast gate, whereas the slow gate is assumed to control both protopores through a cooperative movement of the two carboxy-terminal domains. We here study the role of the carboxy-terminal domain in modulating fast and slow gating of human ClC-2 channels, a ubiquitously expressed ClC-type chloride channel involved in transepithelial solute transport and in neuronal chloride homeostasis. Partial truncation of the carboxy-terminus abolishes function of ClC-2 by locking the channel in a closed position. However, unlike other isoforms, its complete removal preserves function of ClC-2. ClC-2 channels without the carboxy-terminus exhibit fast and slow gates that activate and deactivate significantly faster than in WT channels. In contrast to the prevalent view, a single carboxy-terminus suffices for normal slow gating, whereas both domains regulate fast gating of individual protopores. Our findings demonstrate that the carboxy-terminus is not strictly required for slow gating and that the cooperative gating resides in other regions of the channel protein. ClC-2 is expressed in neurons and believed to open at negative potentials and increased internal chloride concentrations after intense synaptic activity. We propose that the function of the ClC-2 carboxy-terminus is to slow down the time course of channel activation in order to stabilize neuronal excitability.

  10. Deep Gate Recurrent Neural Network

    Science.gov (United States)

    2016-11-22

    and Fred Cummins. Learning to forget: Continual prediction with lstm . Neural computation, 12(10):2451–2471, 2000. Alex Graves. Generating sequences...DSGU) and Simple Gated Unit (SGU), which are structures for learning long-term dependencies. Compared to traditional Long Short-Term Memory ( LSTM ) and...Gated Recurrent Unit (GRU), both structures require fewer parameters and less computation time in sequence classification tasks. Unlike GRU and LSTM

  11. Bill Gates vil redde Folkeskolen

    DEFF Research Database (Denmark)

    Fejerskov, Adam Moe

    2014-01-01

    Det amerikanske uddannelsessystem bliver for tiden udsat for hård kritik, ledt an af Microsoft stifteren Bill Gates. Gates har indtil videre brugt 3 mia. kroner på at skabe opbakning til tiltag som præstationslønning af lærere og strømlining af pensum på tværs af alle skoler i landet...

  12. CMOS gate array characterization procedures

    Science.gov (United States)

    Spratt, James P.

    1993-09-01

    Present procedures are inadequate for characterizing the radiation hardness of gate array product lines prior to personalization because the selection of circuits to be used, from among all those available in the manufacturer's circuit library, is usually uncontrolled. (Some circuits are fundamentally more radiation resistant than others.) In such cases, differences in hardness can result between different designs of the same logic function. Hardness also varies because many gate arrays feature large custom-designed megacells (e.g., microprocessors and random access memories-MicroP's and RAM's). As a result, different product lines cannot be compared equally. A characterization strategy is needed, along with standardized test vehicle(s), methodology, and conditions, so that users can make informed judgments on which gate arrays are best suited for their needs. The program described developed preferred procedures for the radiation characterization of gate arrays, including a gate array evaluation test vehicle, featuring a canary circuit, designed to define the speed versus hardness envelope of the gate array. A multiplier was chosen for this role, and a baseline multiplier architecture is suggested that could be incorporated into an existing standard evaluation circuit chip.

  13. Technical and dosimetric aspects of respiratory gating using a pressure-sensor motion monitoring system

    International Nuclear Information System (INIS)

    Li, X. Allen; Stepaniak, Christopher; Gore, Elizabeth

    2006-01-01

    This work introduces a gating technique that uses 4DCT to determine gating parameters and to plan gated treatment, and employs a Siemens linear accelerator to deliver the gated treatment. Because of technology incompatibility, the 4DCT scanner (LightSpeed, GE) and the Siemens accelerator require two different motion-monitoring systems. The motion monitoring system (AZ-773V, Anzai Med.) used for the gated delivery utilizes a pressure sensor to detect the external respiratory motion (pressure change) in real time. Another system (RPM, Varian) used for the 4DCT scanner (LightSpeed, GE) is based on an infrared camera to detect motion of external markers. These two motion monitoring systems (RPM and Anzai systems) were found to correlate well with each other. The depth doses and profile measured for gated delivery (with a duty cycle of 25% or 50%) were found to agree within 1.0% with those measured for ungated delivery, indicating that gating did not significantly alter beam characteristics. The measurement verified also that the MU linearity and beam output remained unchanged (within 0.3%). A practical method of using 4DCT to plan a gated treatment was developed. The duty cycle for either phase or amplitude gating can be determined based on 4DCT with consideration of set-up error and delivery efficiency. The close-loop measurement involving the entire gating process (imaging, planning, and delivery) showed that the measured isodose distributions agreed with those intended, validating the accuracy and reliability of the gating technique. Based these observations, we conclude that the gating technique introduced in this work, integrating Siemens linear accelerator and Anzai pressure sensor device with GE/Varian RPM 4DCT, is reliable and effective, and it can be used clinically to account for respiratory motion during radiation therapy

  14. Voltage-gated proton channel is expressed on phagosomes

    International Nuclear Information System (INIS)

    Okochi, Yoshifumi; Sasaki, Mari; Iwasaki, Hirohide; Okamura, Yasushi

    2009-01-01

    Voltage-gated proton channel has been suggested to help NADPH oxidase activity during respiratory burst of phagocytes through its activities of compensating charge imbalance and regulation of pH. In phagocytes, robust production of reactive oxygen species occurs in closed membrane compartments, which are called phagosomes. However, direct evidence for the presence of voltage-gated proton channels in phagosome has been lacking. In this study, the expression of voltage-gated proton channels was studied by Western blot with the antibody specific to the voltage-sensor domain protein, VSOP/Hv1, that has recently been identified as the molecular correlate for the voltage-gated proton channel. Phagosomal membranes of neutrophils contain VSOP/Hv1 in accordance with subunits of NADPH oxidases, gp91, p22, p47 and p67. Superoxide anion production upon PMA activation was significantly reduced in neutrophils from VSOP/Hv1 knockout mice. These are consistent with the idea that voltage-gated proton channels help NADPH oxidase in phagocytes to produce reactive oxygen species.

  15. Gate modulation of proton transport in a nanopore.

    Science.gov (United States)

    Mei, Lanju; Yeh, Li-Hsien; Qian, Shizhi

    2016-03-14

    Proton transport in confined spaces plays a crucial role in many biological processes as well as in modern technological applications, such as fuel cells. To achieve active control of proton conductance, we investigate for the first time the gate modulation of proton transport in a pH-regulated nanopore by a multi-ion model. The model takes into account surface protonation/deprotonation reactions, surface curvature, electroosmotic flow, Stern layer, and electric double layer overlap. The proposed model is validated by good agreement with the existing experimental data on nanopore conductance with and without a gate voltage. The results show that the modulation of proton transport in a nanopore depends on the concentration of the background salt and solution pH. Without background salt, the gated nanopore exhibits an interesting ambipolar conductance behavior when pH is close to the isoelectric point of the dielectric pore material, and the net ionic and proton conductance can be actively regulated with a gate voltage as low as 1 V. The higher the background salt concentration, the lower is the performance of the gate control on the proton transport.

  16. 3D modeling of dual-gate FinFET.

    Science.gov (United States)

    Mil'shtein, Samson; Devarakonda, Lalitha; Zanchi, Brian; Palma, John

    2012-11-13

    The tendency to have better control of the flow of electrons in a channel of field-effect transistors (FETs) did lead to the design of two gates in junction field-effect transistors, field plates in a variety of metal semiconductor field-effect transistors and high electron mobility transistors, and finally a gate wrapping around three sides of a narrow fin-shaped channel in a FinFET. With the enhanced control, performance trends of all FETs are still challenged by carrier mobility dependence on the strengths of the electrical field along the channel. However, in cases when the ratio of FinFET volume to its surface dramatically decreases, one should carefully consider the surface boundary conditions of the device. Moreover, the inherent non-planar nature of a FinFET demands 3D modeling for accurate analysis of the device performance. Using the Silvaco modeling tool with quantization effects, we modeled a physical FinFET described in the work of Hisamoto et al. (IEEE Tran. Elec. Devices 47:12, 2000) in 3D. We compared it with a 2D model of the same device. We demonstrated that 3D modeling produces more accurate results. As 3D modeling results came close to experimental measurements, we made the next step of the study by designing a dual-gate FinFET biased at Vg1 >Vg2. It is shown that the dual-gate FinFET carries higher transconductance than the single-gate device.

  17. Fabrication and Optimization of Gelatin/ Nano Bioglass Conduits for Peripheral Nerve Regeneration

    Directory of Open Access Journals (Sweden)

    M. Foroutan Koudehi

    2014-07-01

    Full Text Available Introduction & Objective: Peripheral nerve injury is common in trauma patients and 4.5% of all soft-tissue injuries are accompanied by defects of peripheral nerve. Peripheral nerve injuries can lead to lifetime loss of function and permanent disfigurement. Designed conduits com-prised of natural and synthetic materials are now widely used in the construction of damaged tissues. The aim of this project was to prepare nanocomposite conduits from gelatin and bioglass for damaged peripheral nerve reconstruction. Materials & Methods: In this experimental study,compound water solution of gelatin and nano bioglass synthesized through sol gel method, was made. After preparing the solution, special mandrels were dipped in solution several times and freeze dried in order to be emptied of wa-ter via sublimation. The conduits had the following dimensions: internal diameter: 1.6 mm, outside diameter: 2.2 mm and length about 12 mm. In order to evaluate the biocompatibility of conduits we used cytotoxicity test by Chinese ovary cells and MTT assay by Miapaca-2 (pancreatic cancer cell line. Results: The prepared nano bioglass and conduits were characterized using transmission elec-tron microscopy, scanning electron microscopy, fourier transformed infrared spectroscopy and X-ray diffraction. Results of biocompatibility test showed no sign of cytotoxicity and cells were found to be attached to the pore walls offered by the conduits. Conclusion: According to the results, nano bioglass conduits could be a good candidate for peripheral nerve regeneration. (Sci J Hamadan Univ Med Sci 2014; 21 (2:152-160

  18. Polymeric Nerve Conduits with Contact Guidance Cues Used in Nerve Repair

    Institute of Scientific and Technical Information of China (English)

    G DAI; X NIU; J YIN

    2016-01-01

    In the modern life, the nerve injury frequently happens due to mechanical, chemical or thermal accidents. In the trivial injuries, the peripheral nerves can regenerate on their own; however, in most of the cases the clinical treatments are required, where relatively large nerve injury gaps are formed. Currently, the nerve repair can be accomplished by direct suture when the injury gap is not too large;while the autologous nerve graft working as the gold standard of peripheral nerve injury treatment for nerve injuries with larger gaps. However, the direct suture is limited by heavy tension at the suture sites, and the autologous nerve graft also has the drawbacks of donor site morbidity and insufifcient donor tissue. Recently, artiifcial nerve conduits have been developed as an alternative for clinical nerve repair to overcome the limitations associated with the above treatments. In order to further improve the efifciency of nerve conduits, various guidance cues are incorporated, including physical cues, biochemical signals, as well as support cells. First, this paper reviewed the contact guidance cues applied in nerve conduits, such as lumen ifllers, multi-channels and micro-patterns on the inner surface. Then, the paper focused on the polymeric nerve conduits with micro inner grooves. The polymeric nerve conduits were fabricated using the phase inversion-based ifber spinning techniques. The smart spinneret with grooved die was designed in the spinning platform, while different spinning conditions, including flow rates, air-gap distances, and polymer concentrations, were adjusted to investigate the inlfuence of fabrication conditions on the geometry of nerve conduits. The inner groove size in the nerve conduits can be precisely controlled in our hollow ifber spinning process, which can work as the efifcient contact guidance cue for nerve regeneration.

  19. Visualization of conduit-matrix conductivity differences in a karst aquifer using time-lapse electrical resistivity

    Science.gov (United States)

    Meyerhoff, Steven B.; Karaoulis, Marios; Fiebig, Florian; Maxwell, Reed M.; Revil, André; Martin, Jonathan B.; Graham, Wendy D.

    2012-12-01

    In the karstic upper Floridan aquifer, surface water flows into conduits of the groundwater system and may exchange with water in the aquifer matrix. This exchange has been hypothesized to occur based on differences in discharge at the Santa Fe River Sink-Rise system, north central Florida, but has yet to be visualized using any geophysical techniques. Using electrical resistivity tomography, we conducted a time-lapse study at two locations with mapped conduits connecting the Santa Fe River Sink to the Santa Fe River Rise to study changes of electrical conductivity during times of varying discharge over a six-week period. Our results show conductivity differences between matrix, conduit changes in resistivity occurring through time at the locations of mapped karst conduits, and changes in electrical conductivity during rainfall infiltration. These observations provide insight into time scales and matrix conduit conductivity differences, illustrating how surface water flow recharged to conduits may flow in a groundwater system in a karst aquifer.

  20. Structures and lithofacies of inferred silicic conduits in the Paraná-Etendeka LIP, southernmost Brazil

    Science.gov (United States)

    Simões, M. S.; Lima, E. F.; Sommer, C. A.; Rossetti, L. M. M.

    2018-04-01

    Extensive silicic units in the Paraná-Etendeka LIP have been long interpreted as pyroclastic density currents (rheomorphic ignimbrites) derived from the Messum Complex in Namibia. In recent literature, however, they have been characterized as effusive lava flows and domes. In this paper we describe structures and lithofacies related to postulated silicic lava feeder conduits at Mato Perso, São Marcos and Jaquirana-Cambará do Sul areas in southern Brazil. Inferred conduits are at least 15-25 m in width and the lithofacies include variably vesicular monomictic welded and non-welded breccias in the margins to poorly vesicular, banded, spherulitic and microfractured vitrophyres in the central parts. Flat-lying coherent vitrophyres and massive obsidian are considered to be the subaerial equivalents of the conduits. Large-scale, regional tectonic structures in southern Brazil include the NE-SW aligned Porto Alegre Suture, Leão and Açotea faults besides the Antas Lineament, a curved tectonic feature accompanying the bed of Antas river. South of the Antas Lineament smaller-scale, NW-SE lineaments limit the exposure areas of the inferred conduits. NE-SW and subordinate NW-SE structures within this smaller-scale lineaments are represented by the main postulated conduit outcrops and are parallel to the dominant sub-vertical banding in the widespread banded vitrophyre lithofacies. Upper lava flows display flat-lying foliation, pipe-like and spherical vesicles and have better developed microlites. Petrographic characteristics of the silicic vitrophyres indicate that crystal-poor magmas underwent distinct cooling paths for each inferred conduit area. The vitrophyre chemical composition is defined by the evolution of trachydacitic/dacitic vitrophyres with 62-65 wt% SiO2 to rhyodacite and rhyolite with 66-68 wt% SiO2. The more evolved rocks are assigned to the latest intrusive grey vitrophyre outcropping in the center of the conduits. Degassing pathways formed during

  1. Uncovering Offshore Financial Centers: Conduits and Sinks in the Global Corporate Ownership Network.

    Science.gov (United States)

    Garcia-Bernardo, Javier; Fichtner, Jan; Takes, Frank W; Heemskerk, Eelke M

    2017-07-24

    Multinational corporations use highly complex structures of parents and subsidiaries to organize their operations and ownership. Offshore Financial Centers (OFCs) facilitate these structures through low taxation and lenient regulation, but are increasingly under scrutiny, for instance for enabling tax avoidance. Therefore, the identification of OFC jurisdictions has become a politicized and contested issue. We introduce a novel data-driven approach for identifying OFCs based on the global corporate ownership network, in which over 98 million firms (nodes) are connected through 71 million ownership relations. This granular firm-level network data uniquely allows identifying both sink-OFCs and conduit-OFCs. Sink-OFCs attract and retain foreign capital while conduit-OFCs are attractive intermediate destinations in the routing of international investments and enable the transfer of capital without taxation. We identify 24 sink-OFCs. In addition, a small set of five countries - the Netherlands, the United Kingdom, Ireland, Singapore and Switzerland - canalize the majority of corporate offshore investment as conduit-OFCs. Each conduit jurisdiction is specialized in a geographical area and there is significant specialization based on industrial sectors. Against the idea of OFCs as exotic small islands that cannot be regulated, we show that many sink and conduit-OFCs are highly developed countries.

  2. A simulation for the gated weir opening of Wonokromo River, Rungkut District, Surabaya

    Science.gov (United States)

    Handajani, N.; Wahjudijanto, I.; Mu'afi, M.

    2018-01-01

    The gated weir is a weir that the crest elevation could be operated based on the flow through the river. The upstream water level of the gated weir could be controlled with gate opening or closing. This study applied a simulation with HEC-RAS 4,0 program in order to know the river hydraulic condition after the gated weir has built. According to the rainfall intensity from each sub-watershed, Distribution Log Pearson III with return period 50 years (Q50) was determined to calculate the design flood discharge. By using Rational Method, the design flood discharge is 470 m3/s. The Results show that capacity of the river is able to accomodate Q50 with discharge 470 m3/s and the gate should be fully opened during flood. This condition could passed the normal discharge at + 5.00 m elevation.

  3. Closing remarks

    International Nuclear Information System (INIS)

    Reig, J.

    2007-01-01

    Good afternoon. Before providing the closing remarks on behalf of the NEA, I would like to take this opportunity and make some personal reflections, if you allow me Mr. Chairman. I have had the opportunity to take part in the three workshops on public communication organised by the NEA. In the first one in Paris in 2000, representing my country, Spain, and in the two last ones in Ottawa in 2004 and Tokyo today, on behalf of the NEA. The topics for the three workshops follow a logical order, first the focus was on investing in trust in a time when public communication was becoming a big challenge for the regulators. Second, maintaining and measuring public confidence to assess how credible regulators are in front of the public; and finally here in Tokyo, transparency, which is a basic element to achieve trust and credibility. In my view, a regulatory decision has three main components, it has to be technically sound. legally correct and well communicated. The emphasis in the early years was in the technical matters, till legal issues became a key element to achieve the political acceptance from governments and local authorities. Finally the public communication aspects resulted into a major effort and challenge to achieve social acceptance. (author)

  4. Small-sized conduits in the right ventricular outflow tract in young children: bicuspidalized homografts are a good alternative to standard conduits.

    Science.gov (United States)

    François, Katrien; De Groote, Katya; Vandekerckhove, Kristof; De Wilde, Hans; De Wolf, Daniel; Bové, Thierry

    2017-10-03

    Downsizing a homograft (HG) through bicuspidalization has been used for more than 2 decades to overcome the shortage of small-sized conduits for reconstruction of the right ventricular outflow tract (RVOT) in young children. Our goal was to investigate the durability of bicuspidalized HGs compared with other small HGs. A retrospective analysis of 93 conduits ≤20 mm, implanted over 23 years, was performed. The end-points were survival, structural valve degeneration and conduit replacement. The conduits comprised 40 pulmonary HGs, 12 aortic HGs, 17 bicuspidalized HGs and 24 xenografts. The median age, mean conduit diameter and z-value at implantation were 1.4 (interquartile range 0.3-3) years, 16.5 ± 2.7 mm and 2.8 ± 1.3, respectively. Valve position was heterotopic in 59 patients and orthotopic in 34 patients. At a mean follow-up period of 7.6 ± 5.9 years, the hospital survival rate was 89%. Freedom from explant at 5 and 10 years was 83 ± 5% and 52 ± 6%, respectively. Freedom from structural valve degeneration was 79 ± 5% at 5 years and 47 ± 6% at 10 years [68 ± 8% for pulmonary HG, 42 ± 16% for bicuspidalized HG, 31 ± 15% for aortic HG and 20 ± 9% for xenografts (log rank P right ventricular outflow tract conduit in young children. However, when a small pulmonary HG is unavailable, bicuspidalization offers a valid alternative, preferable to xenograft conduits, at mid-term follow-up. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  5. Population Shift between the Open and Closed States Changes the Water Permeability of an Aquaporin Z Mutant

    DEFF Research Database (Denmark)

    Xin, Lin; Helix Nielsen, Claus; Su, Haibin

    2012-01-01

    gate in the triple mutant with R189 as the primary steric gate in both mutant and WT AqpZ. The double gates (R189 and W43-F183) result in a high population of the closed conformation in the mutant. Occasionally an open state, with diffusive water permeability very close to that of WT AqpZ, was observed...... be modulated and may further point to how aquaporin function can be optimized for biomimetic membrane applications....

  6. Shallow conduit processes of the 1991 Hekla eruption, Iceland

    Science.gov (United States)

    Gudnason, J.; Thordarson, T.; Houghton, B. F.

    2013-12-01

    On January 17, 1991 at 17:00 hrs, the 17th eruption of Hekla since 1104AD began. Lasting for almost two months, it produced 0.02 km3 of icelandite tephra and ~0.15km3 of icelandite lava. This eruption was the third of four eruptions since 1980 with a recurrence period of approximately 10 years, as opposed to a recurrence interval of c. 55 years for the eruptions in the period 1104AD to 1947AD. [1] The last four Hekla eruptions are typified by a 0.5-2 hour-long initial phase of subplinian intensity and discharge ranging from 2900-6700 m3/s [2]. In all 4 events the inital phase was followed by a sustained and relatively low-discharge(sorted tephra fall covering >20,000 km2. Here we examine the first phase of the Hekla 1991 eruption with focus on vesiculation and fragmentation processes in the shallow conduit and ash production. Samples of the tephra fall were collected on snow immediately after the initial phase at multiple sites providing a representative spatial coverage within the 0.1mm isopach [3]. This set was augmented by samples collected in 2012 to provide tighter coverage of near vent region. Grain size of all samples has been measured down to 1 micron. Density measurements have been conducted on 4 near-vent pumice samples (100 clasts each) and the pumice vesicle size distribution has been determined in a selected subset of clasts. The reconstructed whole deposit grain size distribution exhibits a unimodal, log-normal distribution peaking at -3 phi, typical of dry, magmatic fragmentation. Pumice densities range from 520-880 kg/m3 and exhibit a tight unimodal and log-normal distribution indicating a mean vesicularity of 77% to 79% for the magma erupted during the initial phase. Along with preliminary results for bubble number density and vesicle size distribution this implies a single late-stage homogeneous bubble nucleation and very uniform conditions of magma fragmentation during this short-lived initial phase of the Hekla 1991 eruption. 1. Gudmundsson, A

  7. The Use of Degradable Nerve Conduits for Human Nerve Repair: A Review of the Literature

    Directory of Open Access Journals (Sweden)

    M. F. Meek

    2005-01-01

    Full Text Available The management of peripheral nerve injury continues to be a major clinical challenge. The most widely used technique for bridging defects in peripheral nerves is the use of autologous nerve grafts. This technique, however, has some disadvantages. Many alternative experimental techniques have thus been developed, such as degradable nerve conduits. Degradable nerve guides have been extensively studied in animal experimental studies. However, the repair of human nerves by degradable nerve conduits has been limited to only a few clinical studies. In this paper, an overview of the available international published literature on degradable nerve conduits for bridging human peripheral nerve defects is presented for literature available until 2004. Also, the philosophy on the use of nerve guides and nerve grafts is given.

  8. Transverse colon conduit urinary diversion in patients treated with very high dose pelvic irradiation

    International Nuclear Information System (INIS)

    Ravi, R.; Dewan, A.K.; Pandey, K.K.

    1994-01-01

    Urinary diversion may be required in patients receiving pelvic irradiation for gynaecological or genitourinary cancers either as part of a planned or salvage surgical procedure or for urological complications of irradiation. Records were reviewed for 30 such patients who underwent transverse colon conduit as a primary form of urinary diversion. Most of the conduits were constructed using refluxing ureterocolic anastomoses with stents. The results showed no operative mortality. Although the procedure was associated with a complication rate of 37% and a re-operation rate of 20%, there were no bowel or urinary anastomotic leaks. The operation could be safely performed on patients with renal failure, with 83% of such patients showing normal or improved serum creatinine levels post operatively. The advantages of transverse colon conduit urinary diversion are the use of non-irradiated bowel and ureters for diversion. It is recommended as a primary form of urinary diversion in these high risk cases. (Author)

  9. New opening hours of the gates

    CERN Multimedia

    GS Department

    2009-01-01

    Please note the new opening hours of the gates as well as the intersites tunnel from the 19 May 2009: GATE A 7h - 19h GATE B 24h/24 GATE C 7h - 9h\t17h - 19h GATE D 8h - 12h\t13h - 16h GATE E 7h - 9h\t17h - 19h Prévessin 24h/24 The intersites tunnel will be opened from 7h30 to 18h non stop. GS-SEM Group Infrastructure and General Services Department

  10. Collagen-coated polylactic-glycolic acid (PLGA) seeded with neural-differentiated human mesenchymal stem cells as a potential nerve conduit.

    Science.gov (United States)

    Sulong, Ahmad Fadzli; Hassan, Nur Hidayah; Hwei, Ng Min; Lokanathan, Yogeswaran; Naicker, Amaramalar Selvi; Abdullah, Shalimar; Yusof, Mohd Reusmaazran; Htwe, Ohnmar; Idrus, Ruszymah Bt Hj; Haflah, Nor Hazla Mohamed

    2014-01-01

    Autologous nerve grafts to bridge nerve gaps pose various drawbacks. Nerve tissue engineering to promote nerve regeneration using artificial neural conduits has emerged as a promising alternative. To develop an artificial nerve conduit using collagen-coated polylactic-glycolic acid (PLGA) and to analyse the survivability and propagating ability of the neuro-differentiated human mesenchymal stem cells in this conduit. The PLGA conduit was constructed by dip-molding method and coated with collagen by immersing the conduit in collagen bath. The ultra structure of the conduits were examined before they were seeded with neural-differentiated human mesenchymal stem cells (nMSC) and implanted sub-muscularly on nude mice thighs. The non-collagen-coated PLGA conduit seeded with nMSC and non-seeded non-collagen-coated PLGA conduit were also implanted for comparison purposes. The survivability and propagation ability of nMSC was studied by histological and immunohistochemical analysis. The collagen-coated conduits had a smooth inner wall and a highly porous outer wall. Conduits coated with collagen and seeded with nMSCs produced the most number of cells after 3 weeks. The best conduit based on the number of cells contained within it after 3 weeks was the collagen-coated PLGA conduit seeded with neuro-transdifferentiated cells. The collagen-coated PLGA conduit found to be suitable for attachment, survival and proliferation of the nMSC. Minimal cell infiltration was found in the implanted conduits where nearly all of the cells found in the cell seeded conduits are non-mouse origin and have neural cell markers, which exhibit the biocompatibility of the conduits. The collagen-coated PLGA conduit is biocompatible, non-cytotoxic and suitable for use as artificial nerve conduits.

  11. Respiratory gating in cardiac PET

    DEFF Research Database (Denmark)

    Lassen, Martin Lyngby; Rasmussen, Thomas; Christensen, Thomas E

    2017-01-01

    BACKGROUND: Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim...... of our study was to compare the resulting imaging quality by the use of a time-based respiratory gating system in two groups administered either adenosine or dipyridamole as the pharmacological stress agent. METHODS AND RESULTS: Forty-eight patients were randomized to adenosine or dipyridamole cardiac...... stress (82)RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4...

  12. Robustness of holonomic quantum gates

    International Nuclear Information System (INIS)

    Solinas, P.; Zanardi, P.; Zanghi, N.

    2005-01-01

    Full text: If the driving field fluctuates during the quantum evolution this produces errors in the applied operator. The holonomic (and geometrical) quantum gates are believed to be robust against some kind of noise. Because of the geometrical dependence of the holonomic operators can be robust against this kind of noise; in fact if the fluctuations are fast enough they cancel out leaving the final operator unchanged. I present the numerical studies of holonomic quantum gates subject to this parametric noise, the fidelity of the noise and ideal evolution is calculated for different noise correlation times. The holonomic quantum gates seem robust not only for fast fluctuating fields but also for slow fluctuating fields. These results can be explained as due to the geometrical feature of the holonomic operator: for fast fluctuating fields the fluctuations are canceled out, for slow fluctuating fields the fluctuations do not perturb the loop in the parameter space. (author)

  13. Construction of a fuzzy and all Boolean logic gates based on DNA

    DEFF Research Database (Denmark)

    M. Zadegan, Reza; Jepsen, Mette D E; Hildebrandt, Lasse

    2015-01-01

    to the operation of the six Boolean logic gates AND, NAND, OR, NOR, XOR, and XNOR. The logic gate complex is shown to work also when implemented in a three-dimensional DNA origami box structure, where it controlled the position of the lid in a closed or open position. Implementation of multiple microRNA sensitive...... DNA locks on one DNA origami box structure enabled fuzzy logical operation that allows biosensing of complex molecular signals. Integrating logic gates with DNA origami systems opens a vast avenue to applications in the fields of nanomedicine for diagnostics and therapeutics....

  14. A chimeric prokaryotic pentameric ligand–gated channel reveals distinct pathways of activation

    Science.gov (United States)

    Schmandt, Nicolaus; Velisetty, Phanindra; Chalamalasetti, Sreevatsa V.; Stein, Richard A.; Bonner, Ross; Talley, Lauren; Parker, Mark D.; Mchaourab, Hassane S.; Yee, Vivien C.; Lodowski, David T.

    2015-01-01

    Recent high resolution structures of several pentameric ligand–gated ion channels have provided unprecedented details of their molecular architecture. However, the conformational dynamics and structural rearrangements that underlie gating and allosteric modulation remain poorly understood. We used a combination of electrophysiology, double electron–electron resonance (DEER) spectroscopy, and x-ray crystallography to investigate activation mechanisms in a novel functional chimera with the extracellular domain (ECD) of amine-gated Erwinia chrysanthemi ligand–gated ion channel, which is activated by primary amines, and the transmembrane domain of Gloeobacter violaceus ligand–gated ion channel, which is activated by protons. We found that the chimera was independently gated by primary amines and by protons. The crystal structure of the chimera in its resting state, at pH 7.0 and in the absence of primary amines, revealed a closed-pore conformation and an ECD that is twisted with respect to the transmembrane region. Amine- and pH-induced conformational changes measured by DEER spectroscopy showed that the chimera exhibits a dual mode of gating that preserves the distinct conformational changes of the parent channels. Collectively, our findings shed light on both conserved and divergent features of gating mechanisms in this class of channels, and will facilitate the design of better allosteric modulators. PMID:26415570

  15. Factors influencing resident's decision to reside in gated and guarded community

    Science.gov (United States)

    Shamsudin, Zarina; Shamsudin, Shafiza; Zainal, Rozlin

    2017-10-01

    Gated communities are residential areas developed with restricted access with strictly controlled entrances and surrounded by a close perimeter of wall or fences. Developers, conscious of the need to fulfill the requirement of living in modern and sophisticated lifestyle and gated properties become the trend and mushroomed over the past decade. Nowadays, it is obvious that gated and guarded communities become almost a dominant feature of Malaysia housing development projects. The focus of this paper is to identify the factors contribute resident's decision to reside in gated and guarded community and to study social interaction among gated communities' residents. 150 questionnaires were distributed to the residents of selected gated and guarded community area in order to achieve the objectives and analyzed by using Statistical Package for Social Science (SPSS) and descriptive analysis. The result was tabulated and presented in charts and graphs for a clear and better understanding. The five main factors contribute to resident decision to reside in gated communities were identified and ranked; there are privacy, security, location, lifestyle and prestige. Besides, the residents are feeling neutral towards the facilities and services provided in their gated and guarded residential area. A comprehensive improvement towards the facilities and services is needed to reach higher satisfaction from the residents.

  16. FDG-PET identification of infected pulmonary artery conduit following tetralogy of fallot (TOF) repair

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu Yang; Williams, Hadyn; Pucar, Darko [Dept. of Radiology, Medical College of Georgia, Augusta (United States)

    2017-03-15

    Tetralogy of Fallot (TOF) is one of the most common forms of cyanotic congenital heart disease usually managed by serial surgical repairs. The repaired prosthetic valve or conduit is susceptible to life-threatening infection. FDG-PET is an effective alternative to evaluate the source of infection when other examinations are inconclusive. We report an unusual case of an infected pulmonary artery conduit after TOF repair although the echocardiogram was negative for vegetation, which was later confirmed by surgery and pathology. The case highlights the role of FDG-PET as a problem-solving tool for potential endocarditis and cardiac device infection cases after complex cardiac surgery.

  17. Havery Mudd 2014-2015 Computer Science Conduit Clinic Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Aspesi, G [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bai, J [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Deese, R [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shin, L [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-05-12

    Conduit, a new open-source library developed at Lawrence Livermore National Laboratories, provides a C++ application programming interface (API) to describe and access scientific data. Conduit’s primary use is for inmemory data exchange in high performance computing (HPC) applications. Our team tested and improved Conduit to make it more appealing to potential adopters in the HPC community. We extended Conduit’s capabilities by prototyping four libraries: one for parallel communication using MPI, one for I/O functionality, one for aggregating performance data, and one for data visualization.

  18. A rare case of prosthetic endocarditis and dehiscence in a mechanical valved conduit.

    Science.gov (United States)

    Kannan, Arun; Smith, Cristy; Subramanian, Sreekumar; Janardhanan, Rajesh

    2014-02-07

    A middle-aged adult patient with a history of aortic root replacement with a mechanical valved conduit and remote chest trauma was referred to our institution with prosthetic endocarditis. Transoesophageal echocardiogram at our institution confirmed a near-complete dehiscence of the prosthetic aortic valve from the conduit, with significant perivalvular flow forming a pseudoaneurysm. The patient underwent a high-risk re-operation, involving redo aortic root replacement with a homograft after extensive debridement of the infected tissue. The patient was discharged to an outside facility after an uncomplicated hospital course, and remains stable.

  19. FDG-PET identification of infected pulmonary artery conduit following tetralogy of fallot (TOF) repair

    International Nuclear Information System (INIS)

    Zhang, Yu Yang; Williams, Hadyn; Pucar, Darko

    2017-01-01

    Tetralogy of Fallot (TOF) is one of the most common forms of cyanotic congenital heart disease usually managed by serial surgical repairs. The repaired prosthetic valve or conduit is susceptible to life-threatening infection. FDG-PET is an effective alternative to evaluate the source of infection when other examinations are inconclusive. We report an unusual case of an infected pulmonary artery conduit after TOF repair although the echocardiogram was negative for vegetation, which was later confirmed by surgery and pathology. The case highlights the role of FDG-PET as a problem-solving tool for potential endocarditis and cardiac device infection cases after complex cardiac surgery

  20. Biological conduits combining bone marrow mesenchymal stem cells and extracellular matrix to treat long-segment sciatic nerve defects

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2015-01-01

    Full Text Available The transplantation of polylactic glycolic acid conduits combining bone marrow mesenchymal stem cells and extracellular matrix gel for the repair of sciatic nerve injury is effective in some respects, but few data comparing the biomechanical factors related to the sciatic nerve are available. In the present study, rabbit models of 10-mm sciatic nerve defects were prepared. The rabbit models were repaired with autologous nerve, a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells, or a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel. After 24 weeks, mechanical testing was performed to determine the stress relaxation and creep parameters. Following sciatic nerve injury, the magnitudes of the stress decrease and strain increase at 7,200 seconds were largest in the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel group, followed by the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells group, and then the autologous nerve group. Hematoxylin-eosin staining demonstrated that compared with the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells group and the autologous nerve group, a more complete sciatic nerve regeneration was found, including good myelination, regularly arranged nerve fibers, and a completely degraded and resorbed conduit, in the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel group. These results indicate that bridging 10-mm sciatic nerve defects with a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel construct increases the stress relaxation under a constant strain, reducing anastomotic tension. Large elongations under a constant physiological load can limit the anastomotic opening and shift, which is beneficial for the regeneration and functional reconstruction of sciatic nerve. Better

  1. Gate valve and motor-operator research findings

    International Nuclear Information System (INIS)

    Steele, R. Jr.; DeWall, K.G.; Watkins, J.C.; Russell, M.J.; Bramwell, D.

    1995-09-01

    This report provides an update on the valve research being sponsored by the US Nuclear Regulatory Commission (NRC) and conducted at the Idaho National Engineering Laboratory (INEL). The research addresses the need to provide assurance that motor-operated valves can perform their intended safety function, usually to open or close against specified (design basis) flow and pressure loads. This report describes several important developments: Two methods for estimating or bounding the design basis stem factor (in rising-stem valves), using data from tests less severe than design basis tests; a new correlation for evaluating the opening responses of gate valves and for predicting opening requirements; an extrapolation method that uses the results of a best effort flow test to estimate the design basis closing requirements of a gate valve that exhibits atypical responses (peak force occurs before flow isolation); and the extension of the original INEL closing correlation to include low- flow and low-pressure loads. The report also includes a general approach, presented in step-by-step format, for determining operating margins for rising-stem valves (gate valves and globe valves) as well as quarter-turn valves (ball valves and butterfly valves)

  2. Improved axonal regeneration of transected spinal cord mediated by multichannel collagen conduits functionalized with neurotrophin-3 gene.

    Science.gov (United States)

    Yao, L; Daly, W; Newland, B; Yao, S; Wang, W; Chen, B K K; Madigan, N; Windebank, A; Pandit, A

    2013-12-01

    Functionalized biomaterial scaffolds targeted at improving axonal regeneration by enhancing guided axonal growth provide a promising approach for the repair of spinal cord injury. Collagen neural conduits provide structural guidance for neural tissue regeneration, and in this study it is shown that these conduits can also act as a reservoir for sustained gene delivery. Either a G-luciferase marker gene or a neurotrophin-3-encoding gene, complexed to a non-viral, cyclized, PEGylated transfection vector, was loaded within a multichannel collagen conduit. The complexed genes were then released in a controlled fashion using a dual release system both in vitro and in vivo. For evaluation of their biological performance, the loaded conduits were implanted into the completely transected rat thoracic spinal cord (T8-T10). Aligned axon regeneration through the channels of conduits was observed one month post-surgery. The conduits delivering neurotrophin-3 polyplexes resulted in significantly increased neurotrophin-3 levels in the surrounding tissue and a statistically higher number of regenerated axons versus the control conduits (P<0.05). This study suggests that collagen neural conduits delivering a highly effective non-viral therapeutic gene may hold promise for repair of the injured spinal cord.

  3. A novel balloon assisted two-stents telescoping technique for repositioning an embolized stent in the pulmonary conduit.

    Science.gov (United States)

    Kobayashi, Daisuke; Gowda, Srinath T; Forbes, Thomas J

    2014-08-01

    A 9-year-old male, with history of pulmonary atresia and ventricular septal defect, status post complete repair with a 16 mm pulmonary homograft in the right ventricular outflow tract (RVOT) underwent 3110 Palmaz stent placement for conduit stenosis. Following deployment the stent embolized proximally into the right ventricle (RV). We undertook the choice of repositioning the embolized stent into the conduit with a transcatheter approach. Using a second venous access, the embolized stent was carefully maneuvered into the proximal part of conduit with an inflated Tyshak balloon catheter. A second Palmaz 4010 stent was deployed in the distal conduit telescoping through the embolized stent. The Tyshak balloon catheter was kept inflated in the RV to stabilize the embolized stent in the proximal conduit until it was successfully latched up against the conduit with the deployment of the overlapping second stent. One year later, he underwent Melody valve implantation in the pre-stented conduit relieving conduit insufficiency. This novel balloon assisted two-stents telescoping technique is a feasible transcatheter option to secure an embolized stent from the RV to the RVOT. © 2014 Wiley Periodicals, Inc.

  4. Nitric oxide permits hypoxia-induced lymphatic perfusion by controlling arterial-lymphatic conduits in zebrafish and glass catfish

    DEFF Research Database (Denmark)

    Dahl Ejby Jensen, Lasse; Cao, Renhai; Hedlund, Eva-Maria

    2009-01-01

    and lymphatic perfusion. Here we show in the adult zebrafish and glass catfish (Kryptopterus bicirrhis) that blood-lymphatic conduits directly connect arterial vessels to the lymphatic system. Under hypoxic conditions, arterial-lymphatic conduits (ALCs) became highly dilated and linearized by NO...

  5. Dynamic gating window for compensation of baseline shift in respiratory-gated radiation therapy

    International Nuclear Information System (INIS)

    Pepin, Eric W.; Wu Huanmei; Shirato, Hiroki

    2011-01-01

    Purpose: To analyze and evaluate the necessity and use of dynamic gating techniques for compensation of baseline shift during respiratory-gated radiation therapy of lung tumors. Methods: Motion tracking data from 30 lung tumors over 592 treatment fractions were analyzed for baseline shift. The finite state model (FSM) was used to identify the end-of-exhale (EOE) breathing phase throughout each treatment fraction. Using duty cycle as an evaluation metric, several methods of end-of-exhale dynamic gating were compared: An a posteriori ideal gating window, a predictive trend-line-based gating window, and a predictive weighted point-based gating window. These methods were evaluated for each of several gating window types: Superior/inferior (SI) gating, anterior/posterior beam, lateral beam, and 3D gating. Results: In the absence of dynamic gating techniques, SI gating gave a 39.6% duty cycle. The ideal SI gating window yielded a 41.5% duty cycle. The weight-based method of dynamic SI gating yielded a duty cycle of 36.2%. The trend-line-based method yielded a duty cycle of 34.0%. Conclusions: Dynamic gating was not broadly beneficial due to a breakdown of the FSM's ability to identify the EOE phase. When the EOE phase was well defined, dynamic gating showed an improvement over static-window gating.

  6. Travels with Gates - July 2010

    Science.gov (United States)

    New Sanctions SEOUL, South Korea, July 21, 2010 - Secretary of State Hillary Rodham Clinton, in Seoul - Secretary of State Hillary Rodham Clinton and Defense Secretary Robert M. Gates reaffirmed the U.S zone along with Secretary of State Hillary Rodham Clinton and their South Korean counterparts to

  7. Bill Gates eyes healthcare market.

    Science.gov (United States)

    Dunbar, C

    1995-02-01

    The entrepreneurial spirit is still top in Bill Gates' mind as he look toward healthcare and other growth industries. Microsoft's CEO has not intention of going the way of other large technology companies that became obsolete before they could compete today.

  8. Dry dock gate stability modelling

    Science.gov (United States)

    Oktoberty; Widiyanto; Sasono, E. J.; Pramono, S.; Wandono, A. T.

    2018-03-01

    The development of marine transportation needs in Indonesia increasingly opens national shipyard business opportunities to provide shipbuilding services to the shipbuilding vessels. That emphasizes the stability of prime. The ship's decking door becomes an integral part of the efficient place and the specification of the use of the asset of its operational ease. This study aims to test the stability of Dry Dock gate with the length of 35.4 meters using Maxsurf and Hydromax in analyzing the calculation were in its assessment using interval per 500 mm length so that it can get detail data toward longitudinal and transverse such as studying Ship planning in general. The test result shows dry dock gate meets IMO standard with ballast construction containing 54% and 68% and using fix ballast can produce GMt 1,924 m, tide height 11,357m. The GMt value indicates dry dick gate can be stable and firmly erect at the base of the mouth dry dock. When empty ballast produces GMt 0.996 which means dry dock date is stable, but can easily be torn down. The condition can be used during dry dock gate treatment.

  9. Design and production of stopper made of concrete foam composite used for open channel conduit cover and parking bumper

    Science.gov (United States)

    Syam, Bustami; Sebayang, Alexander; Sebayang, Septian; Muttaqin, Maraghi; Darmadi, Harry; Basuki, WS; Sabri, M.; Abda, S.

    2018-03-01

    Open channel conduit is designed and produced with the aims to reduce excess water, whether from rain, seepage, or excess irrigation water in an area. It is also included in one of the important components of urban infrastructure in tackling the problem of flooding and waterlogging. On the roadway, e.g. housing complex the open channel conduits should function the same, however conduit covers are needed. The covers should be also designed to function as parking bumper. This paper discusses the design and production of the stoppers using our newly invented materials; the stoppers are structurally tested under static, dynamic, and bump test. Response of the conduit cover are found from structural analysis using finite element software ANSYS MECHANICAL version 17.5. Two types of stoppers are introduced: flat and curvy configuration. It was obtained that both types are suitable for open channel conduit cover and parking bumper.

  10. Alstom Francis Turbine Ring Gates: from Retrofitting to Commissioning

    Science.gov (United States)

    A, Nguyen P.; G, Labrecque; M-O, Thibault; M, Bergeron; A, Steinhilber; D, Havard

    2014-03-01

    The Ring Gate synchronisation system developed by Alstom is new and patented. It uses hydraulic cylinders connected in pairs by a serial connection. The new hydraulic synchronisation system, when compared to the previous mechanical synchronisation system, has several advantages. It is a compact design; it reduces the number of mechanical components as well as maintenance costs. The new system maintains the Ring Gates robustness. The new approach is an evolution from mechanical to hydraulic synchronization assisted by electronic control. The new synchronization system eliminates several mechanical components that used to add wear and friction and which are usually difficult to adjust during maintenance. Tension chains and sprockets and associated controls are eliminated. Through the position sensors, the redundancy of the ring gate synchronization system makes it predictable and reliable. The electronic control compensates for any variation in operation, for example a leak in the hydraulic system. An emergency closing is possible without the electronic control system due to the stiffness of hydraulic serial connection in the hydraulic cylinder pairs. The Ring Gate can work safely against uneven loads and frictions. The development will be reviewed and its application discussed through commissioning results.

  11. Alstom Francis Turbine Ring Gates: from Retrofitting to Commissioning

    International Nuclear Information System (INIS)

    Nguyen P A; Labrecque G; Thibault M-O; Bergeron M; Steinhilber A; Havard D

    2014-01-01

    The Ring Gate synchronisation system developed by Alstom is new and patented. It uses hydraulic cylinders connected in pairs by a serial connection. The new hydraulic synchronisation system, when compared to the previous mechanical synchronisation system, has several advantages. It is a compact design; it reduces the number of mechanical components as well as maintenance costs. The new system maintains the Ring Gates robustness. The new approach is an evolution from mechanical to hydraulic synchronization assisted by electronic control. The new synchronization system eliminates several mechanical components that used to add wear and friction and which are usually difficult to adjust during maintenance. Tension chains and sprockets and associated controls are eliminated. Through the position sensors, the redundancy of the ring gate synchronization system makes it predictable and reliable. The electronic control compensates for any variation in operation, for example a leak in the hydraulic system. An emergency closing is possible without the electronic control system due to the stiffness of hydraulic serial connection in the hydraulic cylinder pairs. The Ring Gate can work safely against uneven loads and frictions. The development will be reviewed and its application discussed through commissioning results

  12. A Physicochemically Optimized and Neuroconductive Biphasic Nerve Guidance Conduit for Peripheral Nerve Repair.

    Science.gov (United States)

    Ryan, Alan J; Lackington, William A; Hibbitts, Alan J; Matheson, Austyn; Alekseeva, Tijna; Stejskalova, Anna; Roche, Phoebe; O'Brien, Fergal J

    2017-12-01

    Clinically available hollow nerve guidance conduits (NGCs) have had limited success in treating large peripheral nerve injuries. This study aims to develop a biphasic NGC combining a physicochemically optimized collagen outer conduit to bridge the transected nerve, and a neuroconductive hyaluronic acid-based luminal filler to support regeneration. The outer conduit is mechanically optimized by manipulating crosslinking and collagen density, allowing the engineering of a high wall permeability to mitigate the risk of neuroma formation, while also maintaining physiologically relevant stiffness and enzymatic degradation tuned to coincide with regeneration rates. Freeze-drying is used to seamlessly integrate the luminal filler into the conduit, creating a longitudinally aligned pore microarchitecture. The luminal stiffness is modulated to support Schwann cells, with laminin incorporation further enhancing bioactivity by improving cell attachment and metabolic activity. Additionally, this biphasic NGC is shown to support neurogenesis and gliogenesis of neural progenitor cells and axonal outgrowth from dorsal root ganglia. These findings highlight the paradigm that a successful NGC requires the concerted optimization of both a mechanical support phase capable of bridging a nerve defect and a neuroconductive phase with an architecture capable of supporting both Schwann cells and neurons in order to achieve functional regenerative outcome. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Impact of bed rest on conduit artery remodeling: effect of exercise countermeasures.

    NARCIS (Netherlands)

    Duijnhoven, N.T.L. van; Green, D.J.; Felsenberg, D.; Belavy, D.L.; Hopman, M.T.E.; Thijssen, D.H.J.

    2010-01-01

    Physical inactivity is a potent stimulus for vascular remodeling, leading to a marked decrease in conduit artery diameter. However, little is known about the impact of physical inactivity on artery wall thickness or wall:lumen ratio or the potential of exercise countermeasures to modify artery wall

  14. The Railway and the River: Conduits of Dickens’s Imaginary City

    NARCIS (Netherlands)

    Moore, B.; Murail, E.; Thornton, S.

    2017-01-01

    This chapter analyses the railway and the river as two key conduits of Dickens’ imaginary city, arguing that each simultaneously connects and fractures the modern urban world that he depicts. Focusing on Dombey and Son and Our Mutual Friend, the chapter explores how railway and river combine

  15. Phase separation phenomena in branching conduits. Topical report Dec 78-Dec 81

    International Nuclear Information System (INIS)

    Saba, N.; Lahey, R.T. Jr.

    1982-03-01

    The analysis of Light Water Reactor (LWR) Loss-of-Coolant Accidents (LOCA's) requires that one be able to accurately calculate the two-phase flow splits in complex, branching conduits. The purpose of this study is to provide a general method for calculating the phase separation in a branching conduit. The degree of phase separation of a two-phase (air/water) mixture flowing through a plexiglas tee test section was measured. In addition, flow visualization, using high speed photography, was performed. The experimental design considerations, error analysis and the dependence of the observed phase separation on global parameters, such as inlet quality, mass flux and separation angle, are discussed. The pressure gradients were measured along the various conduits and the differential pressure was obtained at the tee junction by extrapolation. It was found that the degree of phase separation was quite pronounced, with the vapor phase preferentially separating into the branch. Using these data, a physically-based empirical model was developed with which to calculate the phasic distribution of a subsonic two-phase mixture in the downstream branches of a branching conduit

  16. 3D Bioprinting of Heterogeneous Aortic Valve Conduits with Alginate/Gelatin Hydrogels

    Science.gov (United States)

    Duan, Bin; Hockaday, Laura A.; Kang, Kevin H.; Butcher, Jonathan T.

    2013-01-01

    Heart valve disease is a serious and growing public health problem for which prosthetic replacement is most commonly indicated. Current prosthetic devices are inadequate for younger adults and growing children. Tissue engineered living aortic valve conduits have potential for remodeling, regeneration, and growth, but fabricating natural anatomical complexity with cellular heterogeneity remain challenging. In the current study, we implement 3D bioprinting to fabricate living alginate/gelatin hydrogel valve conduits with anatomical architecture and direct incorporation of dual cell types in a regionally constrained manner. Encapsulated aortic root sinus smooth muscle cells (SMC) and aortic valve leaflet interstitial cells (VIC) were viable within alginate/gelatin hydrogel discs over 7 days in culture. Acellular 3D printed hydrogels exhibited reduced modulus, ultimate strength, and peak strain reducing slightly over 7-day culture, while the tensile biomechanics of cell-laden hydrogels were maintained. Aortic valve conduits were successfully bioprinted with direct encapsulation of SMC in the valve root and VIC in the leaflets. Both cell types were viable (81.4±3.4% for SMC and 83.2±4.0% for VIC) within 3D printed tissues. Encapsulated SMC expressed elevated alpha-smooth muscle actin when printed in stiff matrix, while VIC expressed elevated vimentin in soft matrix. These results demonstrate that anatomically complex, heterogeneously encapsulated aortic valve hydrogel conduits can be fabricated with 3D bioprinting. PMID:23015540

  17. Enhancing Peripheral Nerve Regeneration with a Novel Drug-Delivering Nerve Conduit

    Science.gov (United States)

    2015-10-01

    our novel nerve conduit. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE...growth in dorsal root ganglion ( DRG ) cell culture Tasks/Subtasks: 1. In Vitro NGF/GNDF release kinetics experiments.......................... (Gale...Axonal growth of DRGs ................................................................ (Terry, Shea) (11-18months) Progress: We have started these

  18. Percutaneous transthoracic computed tomography-guided AICD insertion in a patient with extracardiac Fontan conduit.

    LENUS (Irish Health Repository)

    Murphy, Darra T

    2011-02-01

    Percutaneous pulmonary venous atrial puncture was performed under computed tomography guidance to successfully place an automated implantable cardiac defibrillator into a 26-year-old patient with extracardiac Fontan conduit who had presented with two out-of-hospital cardiac arrests. The procedure avoided the need for lead placement at thoracotomy.

  19. 76 FR 53678 - Calleguas Municipal Water District Notice of Surrender of Exemption (Conduit)

    Science.gov (United States)

    2011-08-29

    ... Municipal Water District Notice of Surrender of Exemption (Conduit) Pursuant to section 4.95(a) of the Commission's regulations,\\1\\ Calleguas Municipal Water District filed with the Commission a petition to... Municipal Water District, 87 FERC ] 62,256 (1999). \\3\\ See filing of July 11, 2011 by Calleguas Municipal...

  20. The QBO as potential amplifier and conduit to lower altitudes of solar cycle influence

    Directory of Open Access Journals (Sweden)

    H. G. Mayr

    2007-06-01

    Full Text Available In several papers, the solar cycle (SC effect in the lower atmosphere has been linked observationally to the Quasi-biennial Oscillation (QBO of the zonal circulation. Salby and Callaghan (2000 in particular analyzed the QBO wind measurements, covering more than 40 years, and discovered that they contain a large SC signature at 20 km. We present here the results from a study with our 3-D Numerical Spectral Model (NSM, which relies primarily on parameterized gravity waves (GW to describe the QBO. In our model, the period of the SC is taken to be 10 years, and the relative amplitude of radiative forcing varies exponentially with height, i.e., 0.2% at the surface, 2% at 50 km, and 20% at 100 km and above. Applying spectral analysis to identify the SC signature, the model generates a relatively large modulation of the QBO, which reproduces the observations qualitatively. The numerical results demonstrate that the QBO modulation, closely tracking the phase of the SC, is robust and persists at least for 70 years. The question is what causes the SC effect, and our analysis shows that four interlocking processes are involved: (1 In the mesosphere at around 60 km, the solar UV variations generate in the zonal winds a SC modulation of the 12-month annual oscillation, which is hemispherically symmetric and confined to equatorial latitudes like the QBO. (2 Although the amplitude of this equatorial annual oscillation (EAO is relatively small, its SC modulation is large and extends into the lower stratosphere under the influence of, and amplified by, wave forcing. (3 The amplitude modulations of both EAO and QBO are essentially in phase with the imposed SC heating for the entire time span of the model simulation. This indicates that, due to positive feedback in the wave mechanism, the EAO apparently provides the pathway and pacemaker for the SC modulation of the QBO. (4 Our analysis demonstrates that the SC modulations of the QBO and EAO are amplified by

  1. Tile drainage as karst: Conduit flow and diffuse flow in a tile-drained watershed

    Science.gov (United States)

    Schilling, K.E.; Helmers, M.

    2008-01-01

    The similarity of tiled-drained watersheds to karst drainage basins can be used to improve understanding of watershed-scale nutrient losses from subsurface tile drainage networks. In this study, short-term variations in discharge and chemistry were examined from a tile outlet collecting subsurface tile flow from a 963 ha agricultural watershed. Study objectives were to apply analytical techniques from karst springs to tile discharge to evaluate water sources and estimate the loads of agricultural pollutants discharged from the tile with conduit, intermediate and diffuse flow regimes. A two-member mixing model using nitrate, chloride and specific conductance was used to distinguish rainwater versus groundwater inputs. Results indicated that groundwater comprised 75% of the discharge for a three-day storm period and rainwater was primarily concentrated during the hydrograph peak. A contrasting pattern of solute concentrations and export loads was observed in tile flow. During base flow periods, tile flow consisted of diffuse flow from groundwater sources and contained elevated levels of nitrate, chloride and specific conductance. During storm events, suspended solids and pollutants adhered to soil surfaces (phosphorus, ammonium and organic nitrogen) were concentrated and discharged during the rapid, conduit flow portion of the hydrograph. During a three-day period, conduit flow occurred for 5.6% of the time but accounted for 16.5% of the total flow. Nitrate and chloride were delivered primarily with diffuse flow (more than 70%), whereas 80-94% of total suspended sediment, phosphorus and ammonium were exported with conduit and intermediate flow regimes. Understanding the water sources contributing to tile drainage and the manner by which pollutant discharge occurs from these systems (conduit, intermediate or diffuse flow) may be useful for designing, implementing and evaluating non-point source reduction strategies in tile-drained landscapes. ?? 2007 Elsevier B.V. All

  2. Thoracoscopic management of volvulus of the gastric conduit following minimally invasive Ivor-Lewis esophagectomy.

    Science.gov (United States)

    Linson, Jeremy; Latzko, Michael; Ahmed, Bestoun; Awad, Ziad

    2016-07-01

    We present a case of emergent thoracoscopic management of volvulus of the gastric conduit following minimally invasive Ivor-Lewis esophagectomy. The patient is a 69-year-old Caucasian male with a history of adenocarcinoma of the lower third of the esophagus. Initial presentation was dysphagia with solid foods, which progressed in severity until he was unable to swallow anything. EUS demonstrated a partially obstructing mass at 33 cm; biopsy revealed poorly differentiated adenocarcinoma, stage T3N2Mx. PET scan did not reveal any metastatic disease. Preoperative management included neo-adjuvant chemoradiation therapy (5-FU and cisplatin) and early placement of a jejunal feeding tube. Intra-operative leak test was performed as a matter of routine following completion of the esophagogastric anastomosis. A nasogastric tube was placed intra-operatively and removed on POD2 according to our standard pathway. Postoperatively, the patient progressed without difficulty to POD4, when we routinely obtain an upper GI swallow study. This demonstrated a lack of transit of contrast through the distal neo-esophagus. Follow-up endoscopy revealed volvulus of the gastric conduit with obliteration of the lumen. We immediately took the patient to the OR for thoracoscopic detorsion, which we accomplished successfully by entering the existing trochar sites and using blunt dissection.␣Upon entering the thoracic cavity, the staple line that had been oriented anteriorly was now posterior. Attachments were gently teased away from the chest wall and the conduit was detorsed and anchored to the chest wall in the correct orientation with silk suture. Intra-operative endoscopy demonstrated a patent conduit. Postoperative upper GI fluoroscopy now showed good transit of contrast. The patient continued to improve and was eventually advanced to mechanical soft diet and discharged on postoperative day 9. Early intervention is indicated in cases of volvulus of the gastric conduit following Ivor

  3. Eternal Rome: Guardian of the Heavenly Gates

    Science.gov (United States)

    Latura, G.

    2016-01-01

    The power of the Roman Empire did not come solely by way of brutal force. A spiritual vision inherited from the Greeks inspired the Romans—an ascent through the classical Planets to the intersections with the Milky Way, where stood the gates of heaven. This vision stretches back, through Macrobius and Cicero, to Plato's Republic and Timaeus. The Eternal City, capital of the Empire for four centuries, claimed control over the celestial portals, a tradition that is traced on Roman coins and medals over thousands of years. Julius Caesar borrowed enormous sums to campaign for the office of Pontifex Maximus—high priest of Rome—spending a fortune on “bread and circuses” to secure the support of the masses. Consolidating power at every turn, Caesar as dictator-for-life became absolute master of Rome, the city that, according to its coins, ruled the cosmos. Though his mortal frame fell to the knives of the senators, Caesar's soul was seen ascending to heaven as a comet. Thus was born the myth of Divvs Ivlivs—the divine avatar of the Roman Empire, whose name would become synonymous with the title of emperor over millennia (German Kaiser, Hungarian Csaszar, Russian Tsar, to name a few). Caesar's heir, Octavian, piously waited for Lepidus to die of old age before grabbing the office of Pontifex Maximus for himself, a title that would define the celestial authority of the ruler of Rome until Gratian renounced it four centuries later. Ambrose, bishop of Milan, convinced Gratian that such a pagan title was not fit for a Christian. Once the Roman emperor discarded the title Pontifex Maximus, the bishop of Rome picked it up and placed it above his own head, as can be seen on coins and medals of the Vatican to this day. In Jubilee years, the Pope knocks down the brick wall that has kept closed the Holy Door for a generation, a ceremony that reaffirms Rome's control of the celestial gates.

  4. Molecular interactions involved in proton-dependent gating in KcsA potassium channels

    Science.gov (United States)

    Posson, David J.; Thompson, Ameer N.; McCoy, Jason G.

    2013-01-01

    The bacterial potassium channel KcsA is gated open by the binding of protons to amino acids on the intracellular side of the channel. We have identified, via channel mutagenesis and x-ray crystallography, two pH-sensing amino acids and a set of nearby residues involved in molecular interactions that influence gating. We found that the minimal mutation of one histidine (H25) and one glutamate (E118) near the cytoplasmic gate completely abolished pH-dependent gating. Mutation of nearby residues either alone or in pairs altered the channel’s response to pH. In addition, mutations of certain pairs of residues dramatically increased the energy barriers between the closed and open states. We proposed a Monod–Wyman–Changeux model for proton binding and pH-dependent gating in KcsA, where H25 is a “strong” sensor displaying a large shift in pKa between closed and open states, and E118 is a “weak” pH sensor. Modifying model parameters that are involved in either the intrinsic gating equilibrium or the pKa values of the pH-sensing residues was sufficient to capture the effects of all mutations. PMID:24218397

  5. Linear gate with prescaled window

    Energy Technology Data Exchange (ETDEWEB)

    Koch, J; Bissem, H H; Krause, H; Scobel, W [Hamburg Univ. (Germany, F.R.). 1. Inst. fuer Experimentalphysik

    1978-07-15

    An electronic circuit is described that combines the features of a linear gate, a single channel analyzer and a prescaler. It allows selection of a pulse height region between two adjustable thresholds and scales the intensity of the spectrum within this window down by a factor 2sup(N) (0<=N<=9), whereas the complementary part of the spectrum is transmitted without being affected.

  6. Interstage evaluation of homograft-valved right ventricle to pulmonary artery conduits for palliation of hypoplastic left heart syndrome.

    Science.gov (United States)

    Sandeep, Nefthi; Punn, Rajesh; Balasubramanian, Sowmya; Smith, Shea N; Reinhartz, Olaf; Zhang, Yulin; Wright, Gail E; Peng, Lynn F; Wise-Faberowski, Lisa; Hanley, Frank L; McElhinney, Doff B

    2018-04-01

    Palliation of hypoplastic left heart syndrome with a standard nonvalved right ventricle to pulmonary artery conduit results in an inefficient circulation in part due to diastolic regurgitation. A composite right ventricle pulmonary artery conduit with a homograft valve has a hypothetical advantage of reducing regurgitation, but may differ in the propensity for stenosis because of valve remodeling. This retrospective cohort study included 130 patients with hypoplastic left heart syndrome who underwent a modified stage 1 procedure with a right ventricle to pulmonary artery conduit from 2002 to 2015. A composite valved conduit (cryopreserved homograft valve anastomosed to a polytetrafluoroethylene tube) was placed in 100 patients (47 aortic, 32 pulmonary, 13 femoral/saphenous vein, 8 unknown), and a nonvalved conduit was used in 30 patients. Echocardiographic functional parameters were evaluated before and after stage 1 palliation and before the bidirectional Glenn procedure, and interstage interventions were assessed. On competing risk analysis, survival over time was better in the valved conduit group (P = .040), but this difference was no longer significant after adjustment for surgical era. There was no significant difference between groups in the cumulative incidence of bidirectional Glenn completion (P = .15). Patients with a valved conduit underwent more interventions for conduit obstruction in the interstage period, but this difference did not reach significance (P = .16). There were no differences between groups in echocardiographic parameters of right ventricle function at baseline or pre-Glenn. In this cohort of patients with hypoplastic left heart syndrome, inclusion of a valved right ventricle to pulmonary artery conduit was not associated with any difference in survival on adjusted analysis and did not confer an identifiable benefit on right ventricle function. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier

  7. Challenges of using electrical resistivity method to locate karst conduits-A field case in the Inner Bluegrass Region, Kentucky

    Science.gov (United States)

    Zhu, J.; Currens, J.C.; Dinger, J.S.

    2011-01-01

    Conduits serve as major pathways for groundwater flow in karst aquifers. Locating them from the surface, however, is one of the most challenging tasks in karst research. Geophysical methods are often deployed to help locate voids by mapping variations of physical properties of the subsurface. Conduits can cause significant contrasts of some physical properties that can be detected; other subsurface features such as water-bearing fractures often yield similar contrasts, which are difficult to distinguish from the effects of the conduits. This study used electrical resistivity method to search for an unmapped karst conduit that recharges Royal Spring in the Inner Bluegrass karst region, Kentucky, USA. Three types of resistivity techniques (surface 2D survey, quasi-3D survey, and time-lapse survey) were used to map and characterize resistivity anomalies. Some of the major anomalies were selected as drilling targets to verify the existence of the conduits. Drilling near an anomaly identified by an electrical resistivity profile resulted in successful penetration of a major water-filled conduit. The drilling results also suggest that, in this study area, low resistivity anomalies in general are associated with water-bearing features. However, differences in the anomaly signals between the water-filled conduit and other water-bearing features such as water-filled fracture zones were undistinguishable. The electrical resistivity method is useful in conduit detection by providing potential drilling targets. Knowledge of geology and hydrogeology about the site and professional judgment also played important roles in locating the major conduit. ?? 2011 Elsevier B.V.

  8. Minimizing coupling loss by selection of twist pitch lengths in multi-stage cable-in-conduit conductors

    International Nuclear Information System (INIS)

    Rolando, G; Nijhuis, A; Devred, A

    2014-01-01

    The numerical code JackPot-ACDC (van Lanen et al 2010 Cryogenics 50 139–48, van Lanen et al 2011 IEEE Trans. Appl. Supercond. 21 1926–9, van Lanen et al 2012 Supercond. Sci. Technol. 25 025012) allows fast parametric studies of the electro-magnetic performance of cable-in-conduit conductors (CICCs). In this paper the code is applied to the analysis of the relation between twist pitch length sequence and coupling loss in multi-stage ITER-type CICCs. The code shows that in the analysed conductors the coupling loss is at its minimum when the twist pitches of the successive cabling stages have a length ratio close to one. It is also predicted that by careful selection of the stage-to-stage twist pitch ratio, CICCs cabled according to long twist schemes in the initial stages can achieve lower coupling loss than conductors with shorter pitches. The result is validated by AC loss measurements performed on prototype conductors for the ITER Central Solenoid featuring different twist pitch sequences. (paper)

  9. Hydration properties of mechanosensitive channel pores define the energetics of gating

    International Nuclear Information System (INIS)

    Anishkin, A; Akitake, B; Kamaraju, K; Chiang, C-S; Sukharev, S

    2010-01-01

    Opening of ion channels directly by tension in the surrounding membrane appears to be the most ancient and simple mechanism of gating. Bacterial mechanosensitive channels MscL and MscS are the best-studied tension-gated nanopores, yet the key physical factors that define their gating are still hotly debated. Here we present estimations, simulations and experimental results showing that hydration of the pore might be one of the major parameters defining the thermodynamics and kinetics of mechanosensitive channel gating. We associate closing of channel pores with complete dehydration of the hydrophobic gate (occlusion by 'vapor lock') and formation of two water-vapor interfaces above and below the constriction. The opening path is the expansion of these interfaces, ultimately leading to wetting of the hydrophobic pore, which does not appear to be the exact reverse of the closing path, thus producing hysteresis. We discuss specifically the role of polar groups (glycines) buried in narrow closed conformations but exposed in the open states that change the wetting characteristics of the pore lining and stabilize conductive states of the channels.

  10. Using MODFLOW with CFP to understand conduit-matrix exchange in a karst aquifer during flooding

    Science.gov (United States)

    Spellman, P.; Screaton, E.; Martin, J. B.; Gulley, J.; Brown, A.

    2011-12-01

    Karst springs may reverse flow when allogenic runoff increases river stage faster than groundwater heads and may exchange of surface water with groundwater in the surrounding aquifer matrix. Recharged flood water is rich in nutrients, metals, and organic matter and is undersaturated with respect to calcite. Understanding the physical processes controlling this exchange of water is critical to understanding metal cycling, redox chemistry and dissolution in the subsurface. Ultimately the magnitude of conduit-matrix exchange should be governed by head gradients between the conduit and the aquifer which are affected by the hydraulic conductivity of the matrix, conduit properties and antecedent groundwater heads. These parameters are interrelated and it is unknown which ones exert the greatest control over the magnitude of exchange. This study uses MODFLOW-2005 coupled with the Conduit Flow Processes (CFP) package to determine how physical properties of conduits and aquifers influence the magnitude of surface water-groundwater exchange. We use hydraulic data collected during spring reversals in a mapped underwater cave that sources Madison Blue Spring in north-central Florida to explore which factors are most important in governing exchange. The simulation focused on a major flood in 2009, when river stage increased by about 10 meters over 9 days. In a series of simulations, we varied hydraulic conductivity, conduit diameter, roughness height and tortuosity in addition to antecedent groundwater heads to estimate the relative effects of each parameter on the magnitude of conduit-matrix exchange. Each parameter was varied across plausible ranges for karst aquifers. Antecedent groundwater heads were varied using well data recorded through wet and dry seasons throughout the spring shed. We found hydraulic conductivity was the most important factor governing exchange. The volume of exchange increased by about 61% from the lowest value (1.8x10-6 m/d) to the highest value (6 m

  11. Lorentz force effect on mixed convection micropolar flow in a vertical conduit

    Science.gov (United States)

    Abdel-wahed, Mohamed S.

    2017-05-01

    The present work provides a simulation of control and filtration process of hydromagnetic blood flow with Hall current under the effect of heat source or sink through a vertical conduit (pipe). This work meets other engineering applications, such as nuclear reactors cooled during emergency shutdown, geophysical transport in electrically conducting and heat exchangers at low velocity conditions. The problem is modeled by a system of partial differential equations taking the effect of viscous dissipation, and these equations are simplified and solved analytically as a series solution using the Differential Transformation Method (DTM). The velocities and temperature profiles of the flow are plotted and discussed. Moreover, the conduit wall shear stress and heat flux are deduced and explained.

  12. Engineering based assessment for a shape design of a pediatric ePTFE pulmonary conduit valve.

    Science.gov (United States)

    Tsuboko, Yusuke; Shiraishi, Yasuyuki; Yamada, Akihiro; Yambe, Tomoyuki; Miura, Hidekazu; Mura, Seitaro; Yamagishi, Masaaki

    2016-08-01

    The authors examined the hemodynamic characteristics of expanded polytetrafluoroethylene (ePTFE) pulmonary valved conduits quantitatively by our originally developed pediatric pulmonary mechanical circulatory system, in order to suggest the optimal shape design. The system consisted of pneumatically driven right atrium and ventricle model, a pulmonary valve chamber, and elastic pulmonary compliance model with peripheral vascular resistance units, a venous reservoir. We employed two different types of ePTFE valve and evaluated the relationship between the leaflets motion and hemodynamic characteristics by using a high-speed video camera. As a result, we successfully reproduced hemodynamic simulations in our pediatric pulmonary mock system. We confirmed that the presence of bulging sinuses in the pulmonary valved conduit reduced the transvalvular energy loss and increased the valve opening area during systolic period. Our engineering-based in vitro analysis could be useful for proposing a shape design optimization of sophisticated pediatric ePTFE pulmonary valve.

  13. AC losses and stability on large cable-in-conduit superconductors

    Science.gov (United States)

    Bruzzone, Pierluigi

    1998-12-01

    The cable-in-conduit superconductors are preferred for applications where the AC losses and stability are a major concern, e.g., fusion magnets and SMES. A review of coupling currents loss results for both NbTi and Nb 3Sn cable-in-conduit conductors (CICC) is presented and the AC loss relevant features are listed, with special emphasis for the role of the interstrand resistance and strand coating. The transient stability approach for CICCs is discussed and the analytical models are quoted as well as the relevant experimental database. The likely spectrum of transient disturbance in CICC is reviewed and the need to account for interstrand current sharing in the design is outlined. Eventually a practical criterion for the interstrand resistance is proposed to link the stability and AC loss design.

  14. Electromagnetic nondestructive testing at high lift-off using a magnetic image conduit

    International Nuclear Information System (INIS)

    Lee, Jin Yi; Jun, Jong Woo; Kim, Jung Min; Le, Min Hhuy

    2013-01-01

    To protect sensors from the extreme environments, such as, heat, moisture, pollution and radiation, cracks must be inspected for; this can be done by measuring the distribution of magnetic fields at high lift-off through nondestructive electro-magnetic testing. However, as the intensity of an electro-magnetic field is inversely proportional to the square of the lift-off, it becomes increasingly difficult to effective inspect a crack as the lift-off increases. In this paper, a magnetic image conduit to minimize the intensity loss of an electro-magnetic field at high lift-off is proposed, and the effectiveness of a conduit for magnetic imaging is verified by means of both theoretical and experimental approaches.

  15. Development and fabrication of superconducting hybrid Cable-In-Conduit-Conductor (CICC) for indigenous fusion programme

    International Nuclear Information System (INIS)

    Singh, A.K.; Hussain, M.M.; Abdulla, K.K.; Singh, R.P.

    2011-01-01

    The Atomic Fuels Division has initiated development and fabrication of Cable-In-Conduit-Conductor (CICC) of various configurations, for superconducting fusion grade magnets required for their indigenous Fusion Programme. The process involves development of high grade superconducting multifilamentary wire, multi stage cabling of superconducting as well as copper wires and, finally, jacketing of the cables in SS316LN tubes. The overview of the development and fabrication of CICC is presented in this article. (author)

  16. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    OpenAIRE

    Christine Radtke

    2016-01-01

    Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropo...

  17. Selective reinnervation: a comparison of recovery following microsuture and conduit nerve repair.

    Science.gov (United States)

    Evans, P J; Bain, J R; Mackinnon, S E; Makino, A P; Hunter, D A

    1991-09-20

    Selective reinnervation was studied by comparing the regeneration across a conventional neurorraphy versus a conduit nerve repair. Lewis rats underwent right sciatic nerve transection followed by one of four different nerve repairs (n = 8/group). In groups I and II a conventional neurorraphy was performed and in groups III and IV the proximal and distal stumps were coapted by use of a silicone conduit with an interstump gap of 5 mm. The proximal and distal stumps in groups I and III were aligned anatomically correct and the proximal stump was rotated 180 degrees in groups II and IV (i.e. proximal peroneal nerve opposite the distal tibial nerve and the proximal tibial nerve opposite the distal peroneal nerve). By 14 weeks, there was an equivalent, but incomplete return in sciatic function index (SFI) in groups I, III, and IV as measured by walking track analysis. However, the SFI became unmeasurable by 6 weeks in all group II animals. At 14 weeks, the percent innervation of the tibialis anterior and medial gastronemius muscles by the peroneal and tibial nerves respectively was estimated by selective compound muscle action potential amplitude recordings. When fascicular alignment was reversed, there was greater tibial (P = 0.02) and lesser peroneal (P = 0.005) innervation of the gastrocnemius muscle in the conduit (group IV) versus the neurorraphy (group II) group. This suggests that the gastrocnemius muscle may be selectively reinnervated by the tibial nerve. However, there was no evidence of selective reinnervation of the tibialis anterior muscle. Despite these differences, the functional recovery in both conduit repair groups (III and IV) was equivalent to a correctly aligned microsuture repair (group I) and superior to that in the incorrectly aligned microsuture repair (group II).

  18. Bronchovascular reconstruction with a bovine pericardial conduit and surgical reintervention due to thrombosis with revascularisation.

    Science.gov (United States)

    Peña, Emilio; Blanco, Montserrat; Otero, Teresa

    2014-01-01

    We present the case of a 57-year-old male with left hilar squamous cell carcinoma infiltrating the pulmonary artery and in whom a sleeve bronchoplasty and angioplasty were performed using a bovine pericardial conduit. Three days post-operatively, graft thrombosis was detected; thrombectomy and graft reconstruction were performed with revascularisation of the graft. Copyright © 2013 SEPAR. Published by Elsevier Espana. All rights reserved.

  19. Adult Stem Cell Based Enhancement of Nerve Conduit for Peripheral Nerve Repair

    Science.gov (United States)

    2016-10-01

    accompanied by injuries to peripheral nerves; if not repaired, the trauma can lead to significant dysfunction and disability . While nerves have the ability to...recovery, minimized disability , and increased quality of life for our wounded warriors. 2. KEYWORDS: Stem Cell, Nerve Conduit, Peripheral Nerve...would be a paradigm shift away from ordering X-rays at 10-12 weeks and only ordering a CT scan. It has the potential to change the standard of care

  20. Cognitive mechanisms associated with auditory sensory gating

    Science.gov (United States)

    Jones, L.A.; Hills, P.J.; Dick, K.M.; Jones, S.P.; Bright, P.

    2016-01-01

    Sensory gating is a neurophysiological measure of inhibition that is characterised by a reduction in the P50 event-related potential to a repeated identical stimulus. The objective of this work was to determine the cognitive mechanisms that relate to the neurological phenomenon of auditory sensory gating. Sixty participants underwent a battery of 10 cognitive tasks, including qualitatively different measures of attentional inhibition, working memory, and fluid intelligence. Participants additionally completed a paired-stimulus paradigm as a measure of auditory sensory gating. A correlational analysis revealed that several tasks correlated significantly with sensory gating. However once fluid intelligence and working memory were accounted for, only a measure of latent inhibition and accuracy scores on the continuous performance task showed significant sensitivity to sensory gating. We conclude that sensory gating reflects the identification of goal-irrelevant information at the encoding (input) stage and the subsequent ability to selectively attend to goal-relevant information based on that previous identification. PMID:26716891

  1. A bistable electromagnetically actuated rotary gate microvalve

    International Nuclear Information System (INIS)

    Luharuka, Rajesh; Hesketh, Peter J

    2008-01-01

    Two types of rotary gate microvalves are developed for flow modulation in microfluidic systems. These microvalves have been tested for an open flow rate of up to 100 sccm and operate under a differential pressure of 6 psig with flow modulation of up to 100. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifice. The gate is suspended by a novel fully compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constrains the gate in all degrees of freedom except for in-plane rotational motion. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow configurations. The rotary gate microvalve is switched with an external electromagnetic actuator. The suspended gate is made of a soft magnetic material and its electromagnetic actuation is based on the operating principle of a variable-reluctance stepper motor

  2. Experimental superposition of orders of quantum gates

    Science.gov (United States)

    Procopio, Lorenzo M.; Moqanaki, Amir; Araújo, Mateus; Costa, Fabio; Alonso Calafell, Irati; Dowd, Emma G.; Hamel, Deny R.; Rozema, Lee A.; Brukner, Časlav; Walther, Philip

    2015-01-01

    Quantum computers achieve a speed-up by placing quantum bits (qubits) in superpositions of different states. However, it has recently been appreciated that quantum mechanics also allows one to ‘superimpose different operations'. Furthermore, it has been shown that using a qubit to coherently control the gate order allows one to accomplish a task—determining if two gates commute or anti-commute—with fewer gate uses than any known quantum algorithm. Here we experimentally demonstrate this advantage, in a photonic context, using a second qubit to control the order in which two gates are applied to a first qubit. We create the required superposition of gate orders by using additional degrees of freedom of the photons encoding our qubits. The new resource we exploit can be interpreted as a superposition of causal orders, and could allow quantum algorithms to be implemented with an efficiency unlikely to be achieved on a fixed-gate-order quantum computer. PMID:26250107

  3. Multicriteria Gain Tuning for Rotorcraft Flight Controls (also entitled The Development of the Conduit Advanced Control System Design and Evaluation Interface with a Case Study Application Fly by Wire Helicopter Design)

    Science.gov (United States)

    Biezad, Daniel

    1997-01-01

    Handling qualities analysis and control law design would seem to be naturally complimenting components of aircraft flight control system design, however these two closely coupled disciplines are often not well integrated in practice. Handling qualities engineers and control system engineers may work in separate groups within an aircraft company. Flight control system engineers and handling quality specialists may come from different backgrounds and schooling and are often not aware of the other group's research. Thus while the handling qualities specifications represent desired aircraft response characteristics, these are rarely incorporated directly in the control system design process. Instead modem control system design techniques are based on servo-loop robustness specifications, and simple representations of the desired control response. Comprehensive handling qualities analysis is often left until the end of the design cycle and performed as a check of the completed design for satisfactory performance. This can lead to costly redesign or less than satisfactory aircraft handling qualities when the flight testing phase is reached. The desire to integrate the fields of handling qualities and flight,control systems led to the development of the CONDUIT system. This tool facilitates control system designs that achieve desired handling quality requirements and servo-loop specifications in a single design process. With CONDUIT, the control system engineer is now able to directly design and control systems to meet the complete handling specifications. CONDUIT allows the designer to retain a preferred control law structure, but then tunes the system parameters to meet the handling quality requirements.

  4. Long distance seawater intrusion through a karst conduit network in the Woodville Karst Plain, Florida

    Science.gov (United States)

    Xu, Zexuan; Bassett, Seth Willis; Hu, Bill; Dyer, Scott Barrett

    2016-08-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electrical conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 11 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This paper documents the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer.

  5. Analysis of aortic root surgery with composite mechanical aortic valve conduit and valve-sparing reconstruction.

    Science.gov (United States)

    Dias, Ricardo Ribeiro; Mejia, Omar Asdrubal Vilca; Fiorelli, Alfredo Inácio; Pomerantzeff, Pablo Maria Alberto; Dias, Altamiro Ribeiro; Mady, Charles; Stolf, Noedir Antonio Groppo

    2010-01-01

    Comparative analysis of early and late results of aortic root reconstruction with aortic valve sparing operations and the composite mechanical valve conduit replacement. From November 2002 to September 2009, 164 consecutive patients with mean age 54 ± 15 years, 115 male, underwent the aortic root reconstruction (125 mechanical valve conduit replacements and 39 valve sparing operations). Sixteen percent of patients had Marfan syndrome and 4.3% had bicuspid aortic valve. One hundred and forty-four patients (88%) were followed for a mean period of 41.1 ± 20.8 months. The hospital mortality was 4.9%, 5.6% in operations with valved conduits and 2.6% in the valve sparing procedures (P valve sparing operations, respectively (95% CI = 70% - 95%, P = 0.001), (95% CI = 82% - 95% P = 0.03) and (95% CI = 81% - 95%, P = 0.03). Multivariate analysis showed that creatinine greater than 1.4 mg/dl, Cabrol operation and renal dialysis were predictors of mortality, respectively, with occurrence chance of 6 (95% CI = 1.8 - 19.5, P = 0.003), 12 (95% CI = 3 - 49.7, P = 0.0004) and 16 (95% CI = 3.6 - 71.3, P = 0.0002). The aortic root reconstruction has a low early and late mortality, high survival free of complications and low need for reoperation. During the late follow-up, valve sparing aortic root reconstructions presented fewer incidences of bleeding, thromboembolic events and endocarditis.

  6. Analytical studies on hotspot temperature of cable-in-conduit conductors

    International Nuclear Information System (INIS)

    Yoshida, Kiyoshi; Takigami, Hiroyoshi; Kubo, Hiroatsu

    2001-01-01

    This paper describes an analytical study to review the hotspot temperature design criteria of the cable-in-conduit conductors for the ITER magnet system. The ITER magnet system uses three kinds of cable-in-conduit conductors for the Toroidal Field (TF) coils, the Central Solenoid (CS) and the Poloidal Field (PF) coils. The amount of copper in the superconducting cable has been defined by using the classical hotspot temperature design criteria that is based on the adiabatic condition. In the current design, ITER superconducting cables include a large amount of pure copper strands to satisfy the classical criteria. However, temperature and stress in the conduit and insulations after quench can be simulated with the quench simulation program and stress analysis program using the latest analysis tools. This analysis shows that the strand temperature is dominated by the conduction along strands and the heat capacity of other conductor materials and coolant. The hotspot temperature depends strongly on the delay time for quench detection. This analysis provides an estimation of delay times for quench detection. The thermal and stress analysis can provide the maximum allowable temperature after quench by determination of a failure or a functional disorder condition of the jacket material and turn insulation. In conclusion, it is found that the current density of the cable space can be increased, by reducing the extra copper strand, thereby, allowing a reduction of the coil radial build. (author)

  7. The Norwood procedure: in favor of the RV-PA conduit.

    Science.gov (United States)

    Barron, David J

    2013-01-01

    Evolution of the Norwood procedure has culminated in there currently being three treatment strategies available for initial management: the 'classical' Norwood (utilizing a Blalock-Taussig shunt), the Norwood with right-ventricle to pulmonary artery (RV-PA) conduit, and the 'hybrid' Norwood procedure utilizing bilateral pulmonary artery banding and ductal stenting. Each variant has its potential advantages and disadvantages, and this paper looks to examine the evidence in favor of each strategy, with emphasis on the supportive data for the RV-PA conduit. The 'classical' procedure has the benefit of the greatest accumulated surgical experience and avoids any incision into the ventricle. However, the diastolic run-off of the Blalock-Taussig shunt can cause hemodynamic instability and unpredictable coronary steal phenomenon. The RV-PA conduit has the advantage of maintaining diastolic pressure with a more stable postoperative course, but at the cost of a ventriculotomy that may have detrimental long-term sequelae. The 'hybrid' procedure has the advantage of avoiding cardiopulmonary bypass, but does not always secure coronary blood flow and has a high inter-stage morbidity and reintervention rate. The evidence shows that each technique may have its place in future management, and that treatment algorithms could emerge that direct the choice of procedure for specific patient groups. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Natural Occurring Silks and Their Analogues as Materials for Nerve Conduits

    Directory of Open Access Journals (Sweden)

    Christine Radtke

    2016-10-01

    Full Text Available Spider silk and its synthetic derivatives have a light weight in combination with good strength and elasticity. Their high cytocompatibility and low immunogenicity make them well suited for biomaterial products such as nerve conduits. Silk proteins slowly degrade enzymatically in vivo, thus allowing for an initial therapeutic effect such as in nerve scaffolding to facilitate endogenous repair processes, and then are removed. Silks are biopolymers naturally produced by many species of arthropods including spiders, caterpillars and mites. The silk fibers are secreted by the labial gland of the larvae of some orders of Holometabola (insects with pupa or the spinnerets of spiders. The majority of studies using silks for biomedical applications use materials from silkworms or spiders, mostly of the genus Nephila clavipes. Silk is one of the most promising biomaterials with effects not only in nerve regeneration, but in a number of regenerative applications. The development of silks for human biomedical applications is of high scientific and clinical interest. Biomaterials in use for biomedical applications have to meet a number of requirements such as biocompatibility and elicitation of no more than a minor inflammatory response, biodegradability in a reasonable time and specific structural properties. Here we present the current status in the field of silk-based conduit development for nerve repair and discuss current advances with regard to potential clinical transfer of an implantable nerve conduit for enhancement of nerve regeneration.

  9. Cardiovascular effects of right ventricle-pulmonary artery valved conduit implantation in experimental pulmonic stenosis

    International Nuclear Information System (INIS)

    Saida, Y.; Tanaka, R.; Fukushima, R.; Hoshi, K.; Hira, S.; Soda, A.; Iizuka, T.; Ishikawa, T.; Nishimura, T.; Yamane, Y.

    2009-01-01

    Right ventricle (RV)-pulmonary artery (PA) valved conduit (RPVC) implantation decreases RV systolic pressure in pulmonic stenosis (PS) by forming a bypass route between the RV and the PA. The present study evaluates valved conduits derived from canine aortae in a canine model of PS produced by pulmonary artery banding (PAB). Pulmonary stenosis was elicited using PAB in 10 conditioned beagles aged 8 months. Twelve weeks after PAB, the dogs were assigned to one group that did not undergo surgical intervention and another that underwent RPVC using denacol-treated canine aortic valved grafts (PAB+RPVC). Twelve weeks later, the rate of change in the RV-PA systolic pressure gradient was significantly decreased in the PAB+RPVC, compared with the PAB group (60.5+-16.7% vs. 108.9+-22.9%; p0.01). In addition, the end-diastolic RV free wall thickness (RVFWd) was significantly reduced in the PAB+RPVC, compared with the PAB group (8.2+-0.2 vs. 9.4+-0.7 mm; p0.05). Thereafter, regurgitation was not evident beyond the conduit valve and the decrease in RV pressure overload induced by RPVC was confirmed. The present results indicate that RPVC can be performed under a beating heart without cardiopulmonary bypass and adapted to dogs with various types of PS, including 'supra valvular' PS or PS accompanied by dysplasia of the pulmonary valve. Therefore, we consider that this method is useful for treating PS in small animals

  10. Continent catheterizable conduit for urinary diversion in children: Applicability and acceptability

    Directory of Open Access Journals (Sweden)

    Shailesh Solanki

    2015-01-01

    Full Text Available Background: Continent catheterizable conduit (CCC has made clean intermittent catheterization (CIC painless and easy. It is applicable in diverse clinical conditions. Nonetheless, convincing the parents for the need of conduit procedure is still difficult. Materials and Methods: A prospective study, included children who underwent CCC procedure from March 2008 to February 2013. The data were assessed for; diagnosis, type of conduit, number of preoperative counselling sessions before acceptance, role of "self-help group" in decision making, parental concern and satisfaction for the procedure. Results: Twenty-nine patients (males; 24, females; 5 underwent CCC procedure for various clinical conditions. The multiple preoperative counselling sessions and creation of "self-help groups" were helped them for decision making. The main concerns among parents were: (1 Impact of procedure on future fertility and sexual life. (2 Patency of native urethral channel. (3 Permanent urinary stoma over the abdomen. Conclusion: CCC procedures are applicable to a wide array of clinical situations with a good outcome. The acceptability of the CCC procedure improves with preoperative counselling of parent/child, initiation of preoperative per urethral CIC and creation of self-help groups.

  11. Influence of conduit flow mechanics on magma rheology and the growth style of lava domes

    Science.gov (United States)

    Husain, Taha; Elsworth, Derek; Voight, Barry; Mattioli, Glen; Jansma, Pamela

    2018-06-01

    We develop a 2-D particle-mechanics model to explore different lava-dome growth styles. These range from endogenous lava dome growth comprising expansion of a ductile dome core to the exogenous extrusion of a degassed lava plug resulting in generation of a lava spine. We couple conduit flow dynamics with surface growth of the evolving lava dome, fuelled by an open-system magma chamber undergoing continuous replenishment. The conduit flow model accounts for the variation in rheology of ascending magma that results from degassing-induced crystallization. A period of reduced effusive flow rates promote enhanced degassing-induced crystallization. A degassed lava plug extrudes exogenously for magmas with crystal contents (ϕ) of 78 per cent, yield strength >1.62 MPa, and at flow rates of 3 m3 s-1) for magma with lower relative yield strengths (p = 3 MPa) at the conduit exit is forced out by the high discharge rate pulse (2 process, which has been observed at Mount St. Helens and other locations, largely reflects gravitational loading of dome with a viscous core, with retardation by yield strength and talus friction.

  12. High speed gated x-ray imagers

    International Nuclear Information System (INIS)

    Kilkenny, J.D.; Bell, P.; Hanks, R.; Power, G.; Turner, R.E.; Wiedwald, J.

    1988-01-01

    Single and multi-frame gated x-ray images with time-resolution as fast as 150 psec are described. These systems are based on the gating of microchannel plates in a stripline configuration. The gating voltage comes from the avalanche breakdown of reverse biased p-n junction producing high power voltage pulses as short as 70 psec. Results from single and four frame x-ray cameras used on Nova are described. 8 refs., 9 figs

  13. Seven channel gated charge to time converter

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, R J; Waddoup, W D [Durham Univ. (UK)

    1977-11-01

    By using a hybrid integrated circuit seven independent gated charge to time converters have been constructed in a single width NIM module. Gate widths from < approximately 10 ns to approximately 300 ns are possible with a resolution of 0.25 pC, linearity is better than +-1 pC over 2.5 decades of input signal height. Together with a multichannel scaling system described in the following paper one has a very powerful multichannel gated ADC system.

  14. Gating-ML: XML-based gating descriptions in flow cytometry.

    Science.gov (United States)

    Spidlen, Josef; Leif, Robert C; Moore, Wayne; Roederer, Mario; Brinkman, Ryan R

    2008-12-01

    The lack of software interoperability with respect to gating due to lack of a standardized mechanism for data exchange has traditionally been a bottleneck, preventing reproducibility of flow cytometry (FCM) data analysis and the usage of multiple analytical tools. To facilitate interoperability among FCM data analysis tools, members of the International Society for the Advancement of Cytometry (ISAC) Data Standards Task Force (DSTF) have developed an XML-based mechanism to formally describe gates (Gating-ML). Gating-ML, an open specification for encoding gating, data transformations and compensation, has been adopted by the ISAC DSTF as a Candidate Recommendation. Gating-ML can facilitate exchange of gating descriptions the same way that FCS facilitated for exchange of raw FCM data. Its adoption will open new collaborative opportunities as well as possibilities for advanced analyses and methods development. The ISAC DSTF is satisfied that the standard addresses the requirements for a gating exchange standard.

  15. Application of near real-time radial semblance to locate the shallow magmatic conduit at Kilauea Volcano, Hawaii

    Science.gov (United States)

    Dawson, P.; Whilldin, D.; Chouet, B.

    2004-01-01

    Radial Semblance is applied to broadband seismic network data to provide source locations of Very-Long-Period (VLP) seismic energy in near real time. With an efficient algorithm and adequate network coverage, accurate source locations of VLP energy are derived to quickly locate the shallow magmatic conduit system at Kilauea Volcano, Hawaii. During a restart in magma flow following a brief pause in the current eruption, the shallow magmatic conduit is pressurized, resulting in elastic radiation from various parts of the conduit system. A steeply dipping distribution of VLP hypocenters outlines a region extending from sea level to about 550 m elevation below and just east of the Halemaumau Pit Crater. The distinct hypocenters suggest the shallow plumbing system beneath Halemaumau consists of a complex plexus of sills and dikes. An unconstrained location for a section of the conduit is also observed beneath the region between Kilauea Caldera and Kilauea Iki Crater.

  16. Diffusive flux in a model of stochastically gated oxygen transport in insect respiration

    Energy Technology Data Exchange (ETDEWEB)

    Berezhkovskii, Alexander M. [Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892 (United States); Shvartsman, Stanislav Y. [Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544 (United States)

    2016-05-28

    Oxygen delivery to insect tissues is controlled by transport through a branched tubular network that is connected to the atmosphere by valve-like gates, known as spiracles. In certain physiological regimes, the spiracles appear to be randomly switching between open and closed states. Quantitative analysis of this regime leads a reaction-diffusion problem with stochastically switching boundary condition. We derive an expression for the diffusive flux at long times in this problem. Our approach starts with the derivation of the passage probability for a single particle that diffuses between a stochastically gated boundary, which models the opening and closing spiracle, and the perfectly absorbing boundary, which models oxygen absorption by the tissue. This passage probability is then used to derive an expression giving the diffusive flux as a function of the geometric parameters of the tube and characteristic time scales of diffusion and gate dynamics.

  17. Benchmarking gate-based quantum computers

    Science.gov (United States)

    Michielsen, Kristel; Nocon, Madita; Willsch, Dennis; Jin, Fengping; Lippert, Thomas; De Raedt, Hans

    2017-11-01

    With the advent of public access to small gate-based quantum processors, it becomes necessary to develop a benchmarking methodology such that independent researchers can validate the operation of these processors. We explore the usefulness of a number of simple quantum circuits as benchmarks for gate-based quantum computing devices and show that circuits performing identity operations are very simple, scalable and sensitive to gate errors and are therefore very well suited for this task. We illustrate the procedure by presenting benchmark results for the IBM Quantum Experience, a cloud-based platform for gate-based quantum computing.

  18. Electrocardiographic gating in positron emission computed tomography

    International Nuclear Information System (INIS)

    Hoffman, E.J.; Phelps, M.E.; Wisenberg, G.; Schelbert, H.R.; Kuhl, D.E.

    1979-01-01

    Electrocardiographic (ECG) synchronized multiple gated data acquisition was employed with positron emission computed tomography (ECT) to obtain images of myocardial blood pool and myocardium. The feasibility and requirements of multiple gated data acquisition in positron ECT were investigated for 13NH3, ( 18 F)-2-fluoro-2-D-deoxyglucose, and ( 11 C)-carboxyhemoglobin. Examples are shown in which image detail is enhanced and image interpretation is facilitated when ECG gating is employed in the data collection. Analysis of count rate data from a series of volunteers indicates that multiple, statistically adequate images can be obtained under a multiple gated data collection format without an increase in administered dose

  19. Sciatic nerve regeneration in rats by a promising electrospun collagen/poly(ε-caprolactone nerve conduit with tailored degradation rate

    Directory of Open Access Journals (Sweden)

    Jiang Xinquan

    2011-07-01

    Full Text Available Abstract Background To cope with the limitations faced by autograft acquisitions particularly for multiple nerve injuries, artificial nerve conduit has been introduced by researchers as a substitute for autologous nerve graft for the easy specification and availability for mass production. In order to best mimic the structures and components of autologous nerve, great efforts have been made to improve the designation of nerve conduits either from materials or fabrication techniques. Electrospinning is an easy and versatile technique that has recently been used to fabricate fibrous tissue-engineered scaffolds which have great similarity to the extracellular matrix on fiber structure. Results In this study we fabricated a collagen/poly(ε-caprolactone (collagen/PCL fibrous scaffold by electrospinning and explored its application as nerve guide substrate or conduit in vitro and in vivo. Material characterizations showed this electrospun composite material which was made of submicron fibers possessed good hydrophilicity and flexibility. In vitro study indicated electrospun collagen/PCL fibrous meshes promoted Schwann cell adhesion, elongation and proliferation. In vivo test showed electrospun collagen/PCL porous nerve conduits successfully supported nerve regeneration through an 8 mm sciatic nerve gap in adult rats, achieving similar electrophysiological and muscle reinnervation results as autografts. Although regenerated nerve fibers were still in a pre-mature stage 4 months postoperatively, the implanted collagen/PCL nerve conduits facilitated more axons regenerating through the conduit lumen and gradually degraded which well matched the nerve regeneration rate. Conclusions All the results demonstrated this collagen/PCL nerve conduit with tailored degradation rate fabricated by electrospinning could be an efficient alternative to autograft for peripheral nerve regeneration research. Due to its advantage of high surface area for cell attachment, it

  20. Polyurethane/Gelatin Nanofibrils Neural Guidance Conduit Containing Platelet-Rich Plasma and Melatonin for Transplantation of Schwann Cells.

    Science.gov (United States)

    Salehi, Majid; Naseri-Nosar, Mahdi; Ebrahimi-Barough, Somayeh; Nourani, Mohammdreza; Khojasteh, Arash; Farzamfar, Saeed; Mansouri, Korosh; Ai, Jafar

    2018-04-01

    The current study aimed to enhance the efficacy of peripheral nerve regeneration using a biodegradable porous neural guidance conduit as a carrier to transplant allogeneic Schwann cells (SCs). The conduit was prepared from polyurethane (PU) and gelatin nanofibrils (GNFs) using thermally induced phase separation technique and filled with melatonin (MLT) and platelet-rich plasma (PRP). The prepared conduit had the porosity of 87.17 ± 1.89%, the contact angle of 78.17 ± 5.30° and the ultimate tensile strength and Young's modulus of 5.40 ± 0.98 MPa and 3.13 ± 0.65 GPa, respectively. The conduit lost about 14% of its weight after 60 days in distilled water. The produced conduit enhanced the proliferation of SCs demonstrated by a tetrazolium salt-based assay. For functional analysis, the conduit was seeded with 1.50 × 10 4 SCs (PU/GNFs/PRP/MLT/SCs) and implanted into a 10-mm sciatic nerve defect of Wistar rat. Three control groups were used: (1) PU/GNFs/SCs, (2) PU/GNFs/PRP/SCs, and (3) Autograft. The results of sciatic functional index, hot plate latency, compound muscle action potential amplitude and latency, weight-loss percentage of wet gastrocnemius muscle and histopathological examination using hematoxylin-eosin and Luxol fast blue staining, demonstrated that using the PU/GNFs/PRP/MLT conduit to transplant SCs to the sciatic nerve defect resulted in a higher regenerative outcome than the PU/GNFs and PU/GNFs/PRP conduits.

  1. Voltage-Gated Calcium Channels

    Science.gov (United States)

    Zamponi, Gerald Werner

    Voltage Gated Calcium Channels is the first comprehensive book in the calcium channel field, encompassing over thirty years of progress towards our understanding of calcium channel structure, function, regulation, physiology, pharmacology, and genetics. This book balances contributions from many of the leading authorities in the calcium channel field with fresh perspectives from risings stars in the area, taking into account the most recent literature and concepts. This is the only all-encompassing calcium channel book currently available, and is an essential resource for academic researchers at all levels in the areas neuroscience, biophysics, and cardiovascular sciences, as well as to researchers in the drug discovery area.

  2. On magma fragmentation by conduit shear stress: Evidence from the Kos Plateau Tuff, Aegean Volcanic Arc

    Science.gov (United States)

    Palladino, Danilo M.; Simei, Silvia; Kyriakopoulos, Konstantinos

    2008-12-01

    Large silicic explosive eruptions are the most catastrophic volcanic events. Yet, the intratelluric mechanisms underlying are not fully understood. Here we report a field and laboratory study of the Kos Plateau Tuff (KPT, 161 ka, Aegean Volcanic Arc), which provides an excellent geological example of conduit processes that control magma vesiculation and fragmentation during intermediate- to large-scale caldera-forming eruptions. A prominent feature of the KPT is the occurrence of quite unusual platy-shaped tube pumice clasts in pyroclastic fall and current deposits from the early eruption phases preceding caldera collapse. On macroscopic and SEM observations, flat clast faces are elongated parallel to tube vesicles, while transverse surfaces often occur at ~ 45° to vesicle elongation. This peculiar pumice texture provides evidence of high shear stresses related to strong velocity gradients normal to conduit walls, which induced vesiculation and fragmentation of the ascending magma. Either an increasing mass discharge rate without adequate enlargement of a narrow central feeder conduit or a developing fissure-like feeder system related to incipient caldera collapse provided suitable conditions for the generation of plate tube pumice within magma volumes under high shear during the pre-climactic KPT eruption phases. This mechanism implies that the closer to the conduit walls (where the stronger are the velocity gradients) the larger was the proportion of plate vs. conventional (lensoid) juvenile fragments in the ascending gas-pyroclast mixture. Consequently, plate pumice clasts were mainly entrained in the outer portions of the jet and convecting regions of a sustained, Plinian-type, eruption column, as well as in occasional lateral blast currents generated at the vent. As a whole, plate pumice clasts in the peripheral portions of the column were transported at lower altitudes and deposited by fallout or partial collapse closer to the vent relative to lensoid ones

  3. Gate current for p+-poly PMOS devices under gate injection conditions

    NARCIS (Netherlands)

    Hof, A.J.; Holleman, J.; Woerlee, P.H.

    2001-01-01

    In current CMOS processing both n+-poly and p+-poly gates are used. The I-V –relationship and reliability of n+-poly devices are widely studied and well understood. Gate currents and reliability for p+-poly PMOS devices under gate injection conditions are not well understood. In this paper, the

  4. The gating cycle of a K+ channel at atomic resolution

    Energy Technology Data Exchange (ETDEWEB)

    Cuello, Luis G. [Center for Membrane Protein Research, Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, United States; Cortes, D. Marien [Center for Membrane Protein Research, Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, United States; Perozo, Eduardo [Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, United States

    2017-11-22

    C-type inactivation in potassium channels helps fine-tune long-term channel activity through conformational changes at the selectivity filter. Here, through the use of cross-linked constitutively open constructs, we determined the structures of KcsA’s mutants that stabilize the selectivity filter in its conductive (E71A, at 2.25 Å) and deep C-type inactivated (Y82A at 2.4 Å) conformations. These structural snapshots represent KcsA’s transient open-conductive (O/O) and the stable open deep C-type inactivated states (O/I), respectively. The present structures provide an unprecedented view of the selectivity filter backbone in its collapsed deep C-type inactivated conformation, highlighting the close interactions with structural waters and the local allosteric interactions that couple activation and inactivation gating. Together with the structures associated with the closed-inactivated state (C/I) and in the well-known closed conductive state (C/O), this work recapitulates, at atomic resolution, the key conformational changes of a potassium channel pore domain as it progresses along its gating cycle.

  5. Gated integrator with signal baseline subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.

    1996-12-17

    An ultrafast, high precision gated integrator includes an opamp having differential inputs. A signal to be integrated is applied to one of the differential inputs through a first input network, and a signal indicative of the DC offset component of the signal to be integrated is applied to the other of the differential inputs through a second input network. A pair of electronic switches in the first and second input networks define an integrating period when they are closed. The first and second input networks are substantially symmetrically constructed of matched components so that error components introduced by the electronic switches appear symmetrically in both input circuits and, hence, are nullified by the common mode rejection of the integrating opamp. The signal indicative of the DC offset component is provided by a sample and hold circuit actuated as the integrating period begins. The symmetrical configuration of the integrating circuit improves accuracy and speed by balancing out common mode errors, by permitting the use of high speed switching elements and high speed opamps and by permitting the use of a small integrating time constant. The sample and hold circuit substantially eliminates the error caused by the input signal baseline offset during a single integrating window. 5 figs.

  6. Gated integrator with signal baseline subtraction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xucheng (Lisle, IL)

    1996-01-01

    An ultrafast, high precision gated integrator includes an opamp having differential inputs. A signal to be integrated is applied to one of the differential inputs through a first input network, and a signal indicative of the DC offset component of the signal to be integrated is applied to the other of the differential inputs through a second input network. A pair of electronic switches in the first and second input networks define an integrating period when they are closed. The first and second input networks are substantially symmetrically constructed of matched components so that error components introduced by the electronic switches appear symmetrically in both input circuits and, hence, are nullified by the common mode rejection of the integrating opamp. The signal indicative of the DC offset component is provided by a sample and hold circuit actuated as the integrating period begins. The symmetrical configuration of the integrating circuit improves accuracy and speed by balancing out common mode errors, by permitting the use of high speed switching elements and high speed opamps and by permitting the use of a small integrating time constant. The sample and hold circuit substantially eliminates the error caused by the input signal baseline offset during a single integrating window.

  7. Electrochemically-gated single-molecule electrical devices

    International Nuclear Information System (INIS)

    Guo, Shaoyin; Artés, Juan Manuel; Díez-Pérez, Ismael

    2013-01-01

    In the last decade, single-molecule electrical contacts have emerged as a new experimental platform that allows exploring charge transport phenomena in individual molecular blocks. This novel tool has evolved into an essential element within the Molecular Electronics field to understand charge transport processes in hybrid (bio)molecule/electrode interfaces at the nanoscale, and prospect the implementation of active molecular components into functional nanoscale optoelectronic devices. Within this area, three-terminal single-molecule devices have been sought, provided that they are highly desired to achieve full functionality in logic electronic circuits. Despite the latest experimental developments offer consistent methods to bridge a molecule between two electrodes (source and drain in a transistor notation), placing a third electrode (gate) close to the single-molecule electrical contact is still technically challenging. In this vein, electrochemically-gated single-molecule devices have emerged as an experimentally affordable alternative to overcome these technical limitations. In this review, the operating principle of an electrochemically-gated single-molecule device is presented together with the latest experimental methodologies to built them and characterize their charge transport characteristics. Then, an up-to-date comprehensive overview of the most prominent examples will be given, emphasizing on the relationship between the molecular structure and the final device electrical behaviour

  8. Active gate driving method for reliability improvement of IGBTs via junction temperature swing reduction

    DEFF Research Database (Denmark)

    Luo, Haoze; Iannuzzo, Francesco; Ma, Ke

    2016-01-01

    be changed according to the amplitude of AC current. Accordingly, a closed-loop thermal control method including the functions of root-mean-square calculation and phase analysis is proposed. Hence ΔTj can be reduced by means of changing losses-related gate resistors on the basis of output fundamental...

  9. Boolean gates on actin filaments

    International Nuclear Information System (INIS)

    Siccardi, Stefano; Tuszynski, Jack A.; Adamatzky, Andrew

    2016-01-01

    Actin is a globular protein which forms long polar filaments in the eukaryotic cytoskeleton. Actin networks play a key role in cell mechanics and cell motility. They have also been implicated in information transmission and processing, memory and learning in neuronal cells. The actin filaments have been shown to support propagation of voltage pulses. Here we apply a coupled nonlinear transmission line model of actin filaments to study interactions between voltage pulses. To represent digital information we assign a logical TRUTH value to the presence of a voltage pulse in a given location of the actin filament, and FALSE to the pulse's absence, so that information flows along the filament with pulse transmission. When two pulses, representing Boolean values of input variables, interact, then they can facilitate or inhibit further propagation of each other. We explore this phenomenon to construct Boolean logical gates and a one-bit half-adder with interacting voltage pulses. We discuss implications of these findings on cellular process and technological applications. - Highlights: • We simulate interaction between voltage pulses using on actin filaments. • We use a coupled nonlinear transmission line model. • We design Boolean logical gates via interactions between the voltage pulses. • We construct one-bit half-adder with interacting voltage pulses.

  10. Boolean gates on actin filaments

    Energy Technology Data Exchange (ETDEWEB)

    Siccardi, Stefano, E-mail: ssiccardi@2ssas.it [The Unconventional Computing Centre, University of the West of England, Bristol (United Kingdom); Tuszynski, Jack A., E-mail: jackt@ualberta.ca [Department of Oncology, University of Alberta, Edmonton, Alberta (Canada); Adamatzky, Andrew, E-mail: andrew.adamatzky@uwe.ac.uk [The Unconventional Computing Centre, University of the West of England, Bristol (United Kingdom)

    2016-01-08

    Actin is a globular protein which forms long polar filaments in the eukaryotic cytoskeleton. Actin networks play a key role in cell mechanics and cell motility. They have also been implicated in information transmission and processing, memory and learning in neuronal cells. The actin filaments have been shown to support propagation of voltage pulses. Here we apply a coupled nonlinear transmission line model of actin filaments to study interactions between voltage pulses. To represent digital information we assign a logical TRUTH value to the presence of a voltage pulse in a given location of the actin filament, and FALSE to the pulse's absence, so that information flows along the filament with pulse transmission. When two pulses, representing Boolean values of input variables, interact, then they can facilitate or inhibit further propagation of each other. We explore this phenomenon to construct Boolean logical gates and a one-bit half-adder with interacting voltage pulses. We discuss implications of these findings on cellular process and technological applications. - Highlights: • We simulate interaction between voltage pulses using on actin filaments. • We use a coupled nonlinear transmission line model. • We design Boolean logical gates via interactions between the voltage pulses. • We construct one-bit half-adder with interacting voltage pulses.

  11. Influence of gate recess on the electronic characteristics of β-Ga2O3 MOSFETs

    Science.gov (United States)

    Lv, Yuanjie; Mo, Jianghui; Song, Xubo; He, Zezhao; Wang, Yuangang; Tan, Xin; Zhou, Xingye; Gu, Guodong; Guo, Hongyu; Feng, Zhihong

    2018-05-01

    Gallium oxide (Ga2O3) metal-oxide-semiconductor field-effect transistors (MOSFETs) were fabricated with gate recess depths of 110 nm and 220 nm, respectively. The gate recess was formed by dry plasma etching with Cr metal as the mask. The fabricated devices with a 25-nm HfO2 gate dielectric both showed a low off-state drain current of about 1.8 × 10-10 A/mm. The effects of recess depth on the electronic characteristics of Ga2O3 MOSFETs were investigated. Upon increasing the recess depth from 110 nm to 220 nm, the saturated drain current decreased from 20.7 mA/mm to 2.6 mA/mm, while the threshold voltage moved increased to +3 V. Moreover, the breakdown voltage increased from 122 V to 190 V. This is mainly because the inverted-trapezoidal gate played the role of a gate-field plate, which suppressed the peak electric field close to the gate.

  12. Microscopic origin of gating current fluctuations in a potassium channel voltage sensor.

    Science.gov (United States)

    Freites, J Alfredo; Schow, Eric V; White, Stephen H; Tobias, Douglas J

    2012-06-06

    Voltage-dependent ion channels open and close in response to changes in membrane electrical potential due to the motion of their voltage-sensing domains (VSDs). VSD charge displacements within the membrane electric field are observed in electrophysiology experiments as gating currents preceding ionic conduction. The elementary charge motions that give rise to the gating current cannot be observed directly, but appear as discrete current pulses that generate fluctuations in gating current measurements. Here we report direct observation of gating-charge displacements in an atomistic molecular dynamics simulation of the isolated VSD from the KvAP channel in a hydrated lipid bilayer on the timescale (10-μs) expected for elementary gating charge transitions. The results reveal that gating-charge displacements are associated with the water-catalyzed rearrangement of salt bridges between the S4 arginines and a set of conserved acidic side chains on the S1-S3 transmembrane segments in the hydrated interior of the VSD. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  13. The memory effect of a pentacene field-effect transistor with a polarizable gate dielectric

    Science.gov (United States)

    Unni, K. N. N.; de Bettignies, Remi; Dabos-Seignon, Sylvie; Nunzi, Jean-Michel

    2004-06-01

    The nonvolatile transistor memory element is an interesting topic in organic electronics. In this case a memory cell consists of only one device where the stored information is written as a gate insulator polarization by a gate voltage pulse and read by the channel conductance control with channel voltage pulse without destruction of the stored information. Therefore such transistor could be the base of non-volatile non-destructively readable computer memory of extremely high density. Also devices with polarizable gate dielectrics can function more effectively in certain circuits. The effective threshold voltage Vt can be brought very close to zero, for applications where the available gate voltage is limited. Resonant and adaptive circuits can be tuned insitu by polarizing the gates. Poly(vinylidene fluoride), PVDF and its copolymer with trifluoroethylene P(VDF-TrFE) are among the best known and most widely used ferroelectric polymers. In this manuscript, we report new results of an organic FET, fabricated with pentacene as the active material and P(VDF-TrFE) as the gate insulator. Application of a writing voltage of -50 V for short duration results in significant change in the threshold voltage and remarkable increase in the drain current. The memory effect is retained over a period of 20 hours.

  14. A gate drive circuit for gate-turn-off (GTO) devices in series stack

    International Nuclear Information System (INIS)

    Despe, O.

    1999-01-01

    A gate-turn-off (GTO) switch is under development at the Advanced Photon Source as a replacement for a thyratron switch in high power pulsed application. The high voltage in the application requires multiple GTOs connected in series. One component that is critical to the success of GTO operation is the gate drive circuit. The gate drive circuit has to provide fast high-current pulses to the GTO gate for fast turn-on and turn-off. It also has to be able to operate while floating at high voltage. This paper describes a gate drive circuit that meets these requirements

  15. Transparently wrap-gated semiconductor nanowire arrays for studies of gate-controlled photoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Nylund, Gustav; Storm, Kristian; Torstensson, Henrik; Wallentin, Jesper; Borgström, Magnus T.; Hessman, Dan; Samuelson, Lars [Solid State Physics, Nanometer Structure Consortium, Lund University, Box 118, S-221 00 Lund (Sweden)

    2013-12-04

    We present a technique to measure gate-controlled photoluminescence (PL) on arrays of semiconductor nanowire (NW) capacitors using a transparent film of Indium-Tin-Oxide (ITO) wrapping around the nanowires as the gate electrode. By tuning the wrap-gate voltage, it is possible to increase the PL peak intensity of an array of undoped InP NWs by more than an order of magnitude. The fine structure of the PL spectrum reveals three subpeaks whose relative peak intensities change with gate voltage. We interpret this as gate-controlled state-filling of luminescing quantum dot segments formed by zincblende stacking faults in the mainly wurtzite NW crystal structure.

  16. Protected gates for topological quantum field theories

    International Nuclear Information System (INIS)

    Beverland, Michael E.; Pastawski, Fernando; Preskill, John; Buerschaper, Oliver; Koenig, Robert; Sijher, Sumit

    2016-01-01

    We study restrictions on locality-preserving unitary logical gates for topological quantum codes in two spatial dimensions. A locality-preserving operation is one which maps local operators to local operators — for example, a constant-depth quantum circuit of geometrically local gates, or evolution for a constant time governed by a geometrically local bounded-strength Hamiltonian. Locality-preserving logical gates of topological codes are intrinsically fault tolerant because spatially localized errors remain localized, and hence sufficiently dilute errors remain correctable. By invoking general properties of two-dimensional topological field theories, we find that the locality-preserving logical gates are severely limited for codes which admit non-abelian anyons, in particular, there are no locality-preserving logical gates on the torus or the sphere with M punctures if the braiding of anyons is computationally universal. Furthermore, for Ising anyons on the M-punctured sphere, locality-preserving gates must be elements of the logical Pauli group. We derive these results by relating logical gates of a topological code to automorphisms of the Verlinde algebra of the corresponding anyon model, and by requiring the logical gates to be compatible with basis changes in the logical Hilbert space arising from local F-moves and the mapping class group

  17. Gates Auto Door Car With Lights Modulated

    OpenAIRE

    Lina Carolina; Luyung Dinani, Skom, MMSi

    2002-01-01

    In scientific writing wi ll be explained about automatic gates with modulated headlights, where to find the car lights were adjusted by the relative frequency darker because of this background that the author alleviate human task in performing daily activities by using an automatic gate with the car lights modulated.

  18. A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

    KAUST Repository

    Melcher, Karsten

    2009-12-03

    Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved ?-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling. © 2009 Macmillan Publishers Limited. All rights reserved.

  19. A gate-latch-lock mechanism for hormone signalling by abscisic acid receptors

    KAUST Repository

    Melcher, Karsten; Ng, Ley-Moy; Zhou, X. Edward; Soon, Fen-Fen; Xu, Yong; Suino-Powell, Kelly M.; Park, Sang-Youl; Weiner, Joshua J.; Fujii, Hiroaki; Chinnusamy, Viswanathan; Kovach, Amanda; Li, Jun; Wang, Yonghong; Li, Jiayang; Peterson, Francis C.; Jensen, Davin R.; Yong, Eu-Leong; Volkman, Brian F.; Cutler, Sean R.; Zhu, Jian-Kang; Xu, H. Eric

    2009-01-01

    Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved ?-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling. © 2009 Macmillan Publishers Limited. All rights reserved.

  20. Multi-gated field emitters for a micro-column

    International Nuclear Information System (INIS)

    Mimura, Hidenori; Kioke, Akifumi; Aoki, Toru; Neo, Yoichiro; Yoshida, Tomoya; Nagao, Masayoshi

    2011-01-01

    We have developed a multi-gated field emitter (FE) such as a quadruple-gated FE with a three-stacked electrode lens and a quintuple-gated FE with a four-stacked electrode lens. Both the FEs can focus the electron beam. However, the quintuple-gated FE has a stronger electron convergence than the quadruple-gated FE, and a beam crossover is clearly observed for the quintuple-gated FE.

  1. Dual-Gate p-GaN Gate High Electron Mobility Transistors for Steep Subthreshold Slope.

    Science.gov (United States)

    Bae, Jong-Ho; Lee, Jong-Ho

    2016-05-01

    A steep subthreshold slope characteristic is achieved through p-GaN gate HEMT with dual-gate structure. Obtained subthreshold slope is less than 120 μV/dec. Based on the measured and simulated data obtained from single-gate device, breakdown of parasitic floating-base bipolar transistor and floating gate charged with holes are responsible to increase abruptly in drain current. In the dual-gate device, on-current degrades with high temperature but subthreshold slope is not changed. To observe the switching speed of dual-gate device and transient response of drain current are measured. According to the transient responses of drain current, switching speed of the dual-gate device is about 10(-5) sec.

  2. Top-gate pentacene-based organic field-effect transistor with amorphous rubrene gate insulator

    Science.gov (United States)

    Hiroki, Mizuha; Maeda, Yasutaka; Ohmi, Shun-ichiro

    2018-02-01

    The scaling of organic field-effect transistors (OFETs) is necessary for high-density integration and for this, OFETs with a top-gate configuration are required. There have been several reports of damageless lithography processes for organic semiconductor or insulator layers. However, it is still difficult to fabricate scaled OFETs with a top-gate configuration. In this study, the lift-off process and the device characteristics of the OFETs with a top-gate configuration utilizing an amorphous (α) rubrene gate insulator were investigated. We have confirmed that α-rubrene shows an insulating property, and its extracted linear mobility was 2.5 × 10-2 cm2/(V·s). The gate length and width were 10 and 60 µm, respectively. From these results, the OFET with a top-gate configuration utilizing an α-rubrene gate insulator is promising for the high-density integration of scaled OFETs.

  3. Effects of pressure and temperature on gate valve unwedging

    Energy Technology Data Exchange (ETDEWEB)

    Damerell, P.S.; Harrison, D.H.; Hayes, P.W.; Simons, J.W.; Walker, T.A.

    1996-12-01

    The stem thrust required to unwedge a gate valve is influenced by the pressure and temperature when the valve is closed and by the changes in these conditions between closure and opening. {open_quotes}Pressure locking{close_quotes} and {open_quotes}thermal binding{close_quotes} refer to situations where pressure and temperature effects cause the unwedging load to be much higher than normal. A model of these phenomena has been developed. Wedging (closure) is modeled as developing an {open_quotes}interference{close_quotes} between the disk and its seat rings in the valve. The effects of pressure and temperature are analyzed to determine the change in this disk-to-seat {open_quotes}interference{close_quotes}. Flexibilities, of the disk, body, stem and yoke strongly influence the unwedging thrust. Calculations and limited comparisons to data have been performed for a range of valve designs and scenarios. Pressure changes can increase the unwedging load when there is either a uniform pressure decrease, or a situation where the bonnet pressure exceeds the pressures in the adjacent piping. Temperature changes can increase the unwedging load when: (1) valve closure at elevated system temperature produces a delayed stem expansion, (2) a temperature increase after closure produces a bonnet pressure increase, or (3) a temperature change after closure produces an increase in the disk-to-seat {open_quotes}interference{close_quotes} or disk-to-seat friction.

  4. Delineating saturated conduit patterns and dimensions in the upper Floridan aquifer through numerical groundwater flow modeling (Invited)

    Science.gov (United States)

    Kincaid, T. R.; Meyer, B. A.

    2009-12-01

    In groundwater flow modeling, aquifer permeability is typically defined through model calibration. Since the pattern and size of conduits are part of a karstic permeability framework, those parameters should be constrainable through the same process given a sufficient density of measured conditions. H2H Associates has completed a dual-permeability steady-state model of groundwater flow through the western Santa Fe River Basin, Florida from which a 380.9 km network of saturated conduits was delineated through model calibration to heads and spring discharges. Two calibration datasets were compiled describing average high-water and average low-water conditions based on heads at 145 wells and discharge from 18 springs for the high-water scenario and heads at 188 wells and discharge from 9 springs for the low-water scenario. An initial conduit network was defined by assigning paths along mapped conduits and inferring paths along potentiometric troughs between springs and swallets that had been connected by groundwater tracing. These initial conduit assignments accounted for only 13.75 and 34.1 km of the final conduit network respectively. The model was setup using FEFLOW™ where conduits were described as discrete features embedded in a porous matrix. Flow in the conduits was described by the Manning-Strickler equation where variables for conduit area and roughness were used to adjust the volume and velocity of spring flows. Matrix flow was described by Darcy’s law where hydraulic conductivity variations were limited to three geologically defined internally homogeneous zones that ranged from ~2E-6 m/s to ~4E-3 m/s. Recharge for both the high-water and low-water periods was determined through a water budget analysis where variations were restricted to nine zones defined by land-use. All remaining variations in observed head were then assumed to be due to conduits. The model was iteratively calibrated to the high-water and low-water datasets wherein the location, size

  5. Numerical modeling and sensitivity analysis of seawater intrusion in a dual-permeability coastal karst aquifer with conduit networks

    Directory of Open Access Journals (Sweden)

    Z. Xu

    2018-01-01

    Full Text Available Long-distance seawater intrusion has been widely observed through the subsurface conduit system in coastal karst aquifers as a source of groundwater contaminant. In this study, seawater intrusion in a dual-permeability karst aquifer with conduit networks is studied by the two-dimensional density-dependent flow and transport SEAWAT model. Local and global sensitivity analyses are used to evaluate the impacts of boundary conditions and hydrological characteristics on modeling seawater intrusion in a karst aquifer, including hydraulic conductivity, effective porosity, specific storage, and dispersivity of the conduit network and of the porous medium. The local sensitivity analysis evaluates the parameters' sensitivities for modeling seawater intrusion, specifically in the Woodville Karst Plain (WKP. A more comprehensive interpretation of parameter sensitivities, including the nonlinear relationship between simulations and parameters, and/or parameter interactions, is addressed in the global sensitivity analysis. The conduit parameters and boundary conditions are important to the simulations in the porous medium because of the dynamical exchanges between the two systems. The sensitivity study indicates that salinity and head simulations in the karst features, such as the conduit system and submarine springs, are critical for understanding seawater intrusion in a coastal karst aquifer. The evaluation of hydraulic conductivity sensitivity in the continuum SEAWAT model may be biased since the conduit flow velocity is not accurately calculated by Darcy's equation as a function of head difference and hydraulic conductivity. In addition, dispersivity is no longer an important parameter in an advection-dominated karst aquifer with a conduit system, compared to the sensitivity results in a porous medium aquifer. In the end, the extents of seawater intrusion are quantitatively evaluated and measured under different scenarios with the variabilities of

  6. Impact of pacing modality and biventricular pacing on cardiac output and coronary conduit flow in the post-cardiotomy patient.

    LENUS (Irish Health Repository)

    Healy, David G

    2012-02-03

    We have previously demonstrated the role of univentricular pacing modalities in influencing coronary conduit flow in the immediate post-operative period in the cardiac surgery patient. We wanted to determine the mechanism of this improved coronary conduit and, in addition, to explore the possible benefits with biventricular pacing. Sixteen patients undergoing first time elective coronary artery bypass grafting who required pacing following surgery were recruited. Comparison of cardiac output and coronary conduit flow was performed between VVI and DDD pacing with a single right ventricular lead and biventricular pacing lead placement. Cardiac output was measured using arterial pulse waveform analysis while conduit flow was measured using ultrasonic transit time methodology. Cardiac output was greatest with DDD pacing using right ventricular lead placement only [DDD-univentricular 5.42 l (0.7), DDD-biventricular 5.33 l (0.8), VVI-univentricular 4.71 l (0.8), VVI-biventricular 4.68 l (0.6)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.023) and VVI-biventricular pacing (P=0.001) but there was no significant advantage to DDD-biventricular pacing (P=0.45). In relation to coronary conduit flow, DDD pacing again had the highest flow [DDD-univentricular 55 ml\\/min (24), DDD-biventricular 52 ml\\/min (25), VVI-univentricular 47 ml\\/min (23), VVI-biventricular 50 ml\\/min (26)]. DDD-univentricular pacing was significantly better than VVI-univentricular (P=0.006) pacing but not significantly different to VVI-biventricular pacing (P=0.109) or DDD-biventricular pacing (P=0.171). Pacing with a DDD modality offers the optimal coronary conduit flow by maximising cardiac output. Biventricular lead placement offered no significant benefit to coronary conduit flow or cardiac output.

  7. Materials Fundamentals of Gate Dielectrics

    CERN Document Server

    Demkov, Alexander A

    2006-01-01

    This book presents materials fundamentals of novel gate dielectrics that are being introduced into semiconductor manufacturing to ensure the continuous scalling of the CMOS devices. This is a very fast evolving field of research so we choose to focus on the basic understanding of the structure, thermodunamics, and electronic properties of these materials that determine their performance in device applications. Most of these materials are transition metal oxides. Ironically, the d-orbitals responsible for the high dielectric constant cause sever integration difficulties thus intrinsically limiting high-k dielectrics. Though new in the electronics industry many of these materials are wel known in the field of ceramics, and we describe this unique connection. The complexity of the structure-property relations in TM oxides makes the use of the state of the art first-principles calculations necessary. Several chapters give a detailed description of the modern theory of polarization, and heterojunction band discont...

  8. NRC Information No. 90-23: Improper installation of Patel conduit seals

    International Nuclear Information System (INIS)

    Rossi, C.E.

    1992-01-01

    On November 6, 1989, the staff at the H.B. Robinson plant notified the NRC that they had discovered that some of the conduit seal grommets used to seal insulated wire conductors entering environmentally qualified instrument housings were oversized for the application. The seals are used to prevent moisture from entering safety-related electrical components following loss-of-coolant accidents. The problem was attributed to inadequate installation instructions that were used when the seals were installed in 1986 and 1987. These instructions listed the grommets by wire gauge size and gave maximum wire insulation diameters for each wire size. In accordance with these instructions, the seals were selected based on wire gauge alone. However, since the insulation thickness for a given wire gauge the correct grommet size would have been the minimum wire insulation diameter for which a particular grommet will achieve an effective seal. The selection of grommet size based only on wire gauge size resulted in the installation of some grommets that were too large to provide an effective seal. As a result, some of the seals failed pressure tests that were designed to simulate post-LOCA pressures. During the investigation of the grommet leakage problem, the Robinson staff also checked the torque on the conduit seal union nuts that are used to compress the seals. EGS Corporation recommends that the union nuts be torqued to 50 ft-lb. On approximately half of the 90 seals inspected, the union nut moved about 1/4 inch when this torque was applied. EGS Corporation reports that 1/4 inch of movement does not necessarily indicate a degraded seal but recommends that the correct torque be verified on a representative sample of installed conduit seals

  9. Visualized Evaluation of Blood Flow to the Gastric Conduit and Complications in Esophageal Reconstruction.

    Science.gov (United States)

    Noma, Kazuhiro; Shirakawa, Yasuhiro; Kanaya, Nobuhiko; Okada, Tsuyoshi; Maeda, Naoaki; Ninomiya, Takayuki; Tanabe, Shunsuke; Sakurama, Kazufumi; Fujiwara, Toshiyoshi

    2018-03-01

    Evaluation of the blood supply to gastric conduits is critically important to avoid complications after esophagectomy. We began visual evaluation of blood flow using indocyanine green (ICG) fluorescent imaging in July 2015, to reduce reconstructive complications. In this study, we aimed to statistically verify the efficacy of blood flow evaluation using our simplified ICG method. A total of 285 consecutive patients who underwent esophagectomy and gastric conduit reconstruction were reviewed and divided into 2 groups: before and after introduction of ICG evaluation. The entire cohort and 68 patient pairs after propensity score matching (PS-M) were evaluated for clinical outcomes and the effect of visualized evaluation on reducing the risk of complication. The leakage rate in the ICG group was significantly lower than in the non-ICG group for each severity grade, both in the entire cohort (285 subjects) and after PS-M; the rates of other major complications, including recurrent laryngeal nerve palsy and pneumonia, were not different. The duration of postoperative ICU stay was approximately 1 day shorter in the ICG group than in the non-ICG group in the entire cohort, and approximately 2 days shorter after PS-M. Visualized evaluation of blood flow with ICG methods significantly reduced the rate of anastomotic complications of all Clavien-Dindo (CD) grades. Odds ratios for ICG evaluation decreased with CD grade (0.3419 for CD ≥ 1; 0.241 for CD ≥ 2; and 0.2153 for CD ≥ 3). Objective evaluation of blood supply to the reconstructed conduit using ICG fluorescent imaging reduces the risk and degree of anastomotic complication. Copyright © 2017 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  10. Myectomy and LA-to-LV Conduit for Severe Calcific Mitral Stenosis and Hypertrophic Cardiomyopathy.

    Science.gov (United States)

    Meghji, Zahara; Nguyen, Anita; Geske, Jeffrey B; Schaff, Hartzell V

    2018-02-26

    Severe calcific mitral valve stenosis can rarely occur concomitantly with obstructive hypertrophic cardiomyopathy. In these patients, surgical decalcification of the stenotic mitral valve followed by mitral valve replacement carries significant operative risk and may result in paravalvular leakage, atrioventricular groove disruption, and excessive bleeding. We report the first 2 cases of obstructive hypertrophic cardiomyopathy with severe calcific mitral valve stenosis successfully treated with concomitant transaortic septal myectomy and bypass of the stenotic mitral valve using a valved left atrium to left ventricular conduit. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Robotic Assisted Radical Cystoprostatectomy and Intracorporeal Ileal Conduit Urinary Diversion for a Kidney Transplant Recipient

    Directory of Open Access Journals (Sweden)

    Peter A. Caputo

    Full Text Available ABSTRACT Introduction and Objectives: Robotic assisted radical cystectomy (RARC is an alternative to open radical cystectomy. As experience is gained with the RARC approach the technique is being applied to more complex surgical cases. We describe here our technique for RARC with intracorporeal ileal conduit urinary diversion for a renal transplant recipient. Materials and Methods: The patient is a 60-year old man with high-grade muscle invasive bladder cancer. He has a history of renal failure due to polycystic kidney disease and received a deceased donor renal transplant in 2008. His hospital course at time of transplant was complicated by low-level BK virus viremia. Interestingly his trans-urethral bladder tumor resection specimen at time of bladder cancer diagnosis stained positive for SV40. His native kidneys were anuric so bilateral laparoscopic nephrectomy was performed in a staged fashion 2 weeks prior to RARC. Our surgical technique utilizes 6 trocars, of note a 12-mm assistant trocar is placed 1 cm superior to the pubic symphysis, and this trocar is solely used to pass a laparoscopic stapler to facilitate the excision of the ileal segment and the stapled enteric anastomosis. Surgical steps include: identification of native ureters bilaterally (removed en bloc with the bladder specimen; identification of the transplanted ureter at the right bladder dome; posterior bladder and prostate dissection along Denonvilliers’ fascia; development of the space of Retzius; ligation and transection of the bladder and prostate vascular bundles; apical prostate dissection and transection of urethra; left pelvic lymphadenectomy; ilium resection for creation of the ileal conduit; stapled enteric anastomosis; ureteroileal anastomosis; maturation of the ileal conduit stoma. Results: The surgery had no intraoperative complications. Operative time was 443 minutes (7.4 hours. Estimated blood loss was 250 cc. Length of hospital stay was 5 days. The patient

  12. Clinical experience with an alloplastic stoma prosthesis (Biocarbon) for urinary conduits and cutaneous ureterostomy.

    Science.gov (United States)

    Månsson, W; Harzmann, R

    1988-01-01

    An alloplastic stoma prosthesis, Biocarbon, composed of 99.9% pure carbon in vitreous form, was used in six patients with conduit urinary diversion and in seven with cutaneous ureterostomy. The patients were thereafter observed for 2-86 months. Complications were subcutaneous infection, urinary fistula and ureteral stenosis, which necessitated removal of the prosthesis in most cases. The permanent stoma, without need for adhesive collecting device, was appreciated by the patients. Problems relating to biocompatibility remain to be solved before the place of the stoma prosthesis in urinary diversion can be determined.

  13. Vulcanian explosions at Volcán de Colima, Mexico: modelling the conduit processes

    Science.gov (United States)

    Varley, N. R.; Stevenson, J.; Johnson, J.; Reyes, G.; Weber, K.; Sanderson, R.

    2006-12-01

    Activity at Volcán de Colima has increased over the past 8 years, and is possibly building towards a significant eruption. Monitoring its current activity is therefore critical, with recent expansion of the network providing new types of data which need to be understood. Recent activity has consisted of 3 effusive episodes lasting up to 22 months, separated by periods characterised by daily Vulcanian eruptions of small to moderate size; the largest producing pyroclastic flows reaching over 5 km, representing the most significant since the last Plinian event (1913). A model has been proposed to explain the mechanism of the Vulcanian explosions, derived through integrating different data including seismicity, SO2 flux and the ascent velocity and thermal emission of the eruption column. Infrasound measurements have helped to demonstrate the variability in the distribution of energy produced by the events. Swarms of low frequency seismic events were associated with the largest magnitude explosions and have been examined statistically with variations observed in the magnitude-frequency relationship of each swarm and their distribution. Seismic evidence of migration of the source has been identified, maybe explained by brittle fracturing associated with an increasing pressure differential within the conduit system. Volcán de Colima has a complex edifice structure with explosions switching between multiple vents and showing pulsing. Variation in remotely monitored fumarole temperatures has also been related to the explosive activity. It is clear that small variations of certain critical factors within the conduit system can lead to a transition between effusive and explosive activity. Frequent transitions at Volcán de Colima provide an ideal opportunity to analyse variations in the observable signals and deduce relationships with changes within the conduit that influence magma ascent and degassing, such as its volatile contents or ascent velocity. One goal of this

  14. Measurement of nanosize etched pits in SiO2 optical fiber conduit using AFM

    International Nuclear Information System (INIS)

    Espinosa, G.; Golzarri, J.I.; Vazquez, C.; Fragoso, R.

    2003-01-01

    Fission fragment tracks from 252 Cf have been observed in SiO 2 optical fiber, using an atomic force microscope (AFM), after a very short chemical etching in hydrofluoric acid solution at normal temperature. The nuclear track starting and evolution process is followed by the AFM direct measurements on the material surface and beyond a fine layer of the surface material. The images of the scanned cones were determined observing the two predominant energies from 252 Cf fission fragments and the development of the tracks in the 150 μm diameter optical fiber conduit

  15. Permeability Measurements of Rock Samples from Conduit Drilling at Unzen Volcano, Japan

    Science.gov (United States)

    Watanabe, T.; Shimizu, Y.; Noguchi, S.; Nakada, S.

    2006-12-01

    The last eruption of Unzen Volcano (1990-1995) was effusive to form lava domes, though magmas at depths are estimated to have contained volatile materials enough to cause explosive eruptions [e.g., Sato et al., 1995]. Most of volatile materials should have escaped from ascending magmas. The escape of gas is controlled by permeability of magmas and country rocks. Unzen Scientific Drilling Project sampled both the latest conduit and its country rock (USDP-4). In order to understand degassing processes, we have measured the permeability of these rock samples. Four cube samples with edges of 25 mm were cut from USDP-4 cores C1, C12 (country rock), C13 and C14 (conduit). Sample C1 is considered as Old Unzen Lava, and Sample C12 volcanic breccia. The transient pulse method was employed to measure the permeability. It applies a step of the fluid pressure difference across a specimen, and measures the decay rate of the fluid pressure difference. This method can be applied to samples with very low permeability, since it determines the permeability without measuring the fluid flux. Nitrogen gas was used as a pore fluid. Our permeametry system is built in a pressure vessel, and the confining pressure and the pore fluid pressure can be controlled independently. The temperature of the measurement system is kept constant within 0.1 degree. The temperature control and the background leak rate limit the measurable permeability to be higher than 10^{-20} m2. Measurements were first conducted under the atmospheric pressure. The permeability in a rock sample varies with the direction by a factor less than 5. Sample C1 has the lowest permeability (10^{-19} m2), and Sample C12 the highest value (10^{-17 m2). The permeability of C13 and C14 is of the order of 10^{- 18} m2. Though only a trace of vesicles can be seen in conduit samples, the interconnection is still maintained. The pressure dependence of the permeability is now investigated up to 50 MPa. The permeability of C13 and C14

  16. A new venous conduit utilizing the recipient portal vein branches for segment V in adult partial liver transplantation.

    Science.gov (United States)

    Moon, I S; Kim, D G; Lee, M D; Hong, S K; Park, S C; Oh, D Y; Ahn, S T; Lee, Y J

    2005-03-01

    Right anterior-medial lobe congestion due to temporary clamping of segment V and/or VIII is common in the operative theater during adult donor right lobe liver transplantation, the most common procedure in our institute. We have used an autogenous saphenous vein conduit to recipient portal vein tributaries in 15 cases, as a "Y-to-I venoplasty" since January 2004. The recipient portal vein is transected 5 mm proximal to its bifurcation and extended to both sides with partial hepatic dissection. The "Y-to-I venoplasty" is made by suture closure of the portal vein transversely to form a tube. The average length is 7.5 cm with a 1.3 cm width. One end of "Y-to-I venoplasty" conduit is anastomosed to the donor segment V branch on the back table. And the other end is anastomosed directly to the IVC via a new window or the middle hepatic vein stump in recipient. The phase distension of the conduit with respiration is noted in the operative field. A 6/15 (40%) patency rate, was observed by CT angiography at the second postoperative week. All-patient conduits showed good flow on serial examinations at the 60th postoperative day. This new venous graft, made of recipient portal vein is a good conduit for segment V decongestion in adult right lobe partial liver transplantation.

  17. Getting started with FortiGate

    CERN Document Server

    Fabbri, Rosato

    2013-01-01

    This book is a step-by-step tutorial that will teach you everything you need to know about the deployment and management of FortiGate, including high availability, complex routing, various kinds of VPN working, user authentication, security rules and controls on applications, and mail and Internet access.This book is intended for network administrators, security managers, and IT pros. It is a great starting point if you have to administer or configure a FortiGate unit, especially if you have no previous experience. For people that have never managed a FortiGate unit, the book helpfully walks t

  18. Optimizing the Gating System for Steel Castings

    Directory of Open Access Journals (Sweden)

    Jan Jezierski

    2018-04-01

    Full Text Available The article presents the attempt to optimize a gating system to produce cast steel castings. It is based on John Campbell’s theory and presents the original results of computer modelling of typical and optimized gating systems for cast steel castings. The current state-of-the-art in cast steel casting foundry was compared with several proposals of optimization. The aim was to find a compromise between the best, theoretically proven gating system version, and a version that would be affordable in industrial conditions. The results show that it is possible to achieve a uniform and slow pouring process even for heavy castings to preserve their internal quality.

  19. Calibration of submerged multi-sluice gates

    Directory of Open Access Journals (Sweden)

    Mohamed F. Sauida

    2014-09-01

    The main objective of this work is to study experimentally and verify empirically the different parameters affecting the discharge through submerged multiple sluice gates (i.e., the expansion ratios, gates operational management, etc.. Using multiple regression analysis of the experimental results, a general equation for discharge coefficient is developed. The results show, that the increase in the expansion ratio and the asymmetric operation of gates, give higher values for the discharge coefficient. The obtained predictions of the discharge coefficient using the developed equations are compared to the experimental data. The present developed equations showed good consistency and high accuracy.

  20. Mechanics of channel gating of the nicotinic acetylcholine receptor.

    Directory of Open Access Journals (Sweden)

    Xinli Liu

    2008-01-01

    Full Text Available The nicotinic acetylcholine receptor (nAChR is a key molecule involved in the propagation of signals in the central nervous system and peripheral synapses. Although numerous computational and experimental studies have been performed on this receptor, the structural dynamics of the receptor underlying the gating mechanism is still unclear. To address the mechanical fundamentals of nAChR gating, both conventional molecular dynamics (CMD and steered rotation molecular dynamics (SRMD simulations have been conducted on the cryo-electron microscopy (cryo-EM structure of nAChR embedded in a dipalmitoylphosphatidylcholine (DPPC bilayer and water molecules. A 30-ns CMD simulation revealed a collective motion amongst C-loops, M1, and M2 helices. The inward movement of C-loops accompanying the shrinking of acetylcholine (ACh binding pockets induced an inward and upward motion of the outer beta-sheet composed of beta9 and beta10 strands, which in turn causes M1 and M2 to undergo anticlockwise motions around the pore axis. Rotational motion of the entire receptor around the pore axis and twisting motions among extracellular (EC, transmembrane (TM, and intracellular MA domains were also detected by the CMD simulation. Moreover, M2 helices undergo a local twisting motion synthesized by their bending vibration and rotation. The hinge of either twisting motion or bending vibration is located at the middle of M2, possibly the gate of the receptor. A complementary twisting-to-open motion throughout the receptor was detected by a normal mode analysis (NMA. To mimic the pulsive action of ACh binding, nonequilibrium MD simulations were performed by using the SRMD method developed in one of our laboratories. The result confirmed all the motions derived from the CMD simulation and NMA. In addition, the SRMD simulation indicated that the channel may undergo an open-close (O C motion. The present MD simulations explore the structural dynamics of the receptor under its

  1. Conduit degassing and thermal controls on eruption styles at Mount St. Helens

    Science.gov (United States)

    Schneider, Andrew; Rempel, Alan W.; Cashman, Katharine V.

    2012-12-01

    The explosivity of silicic eruptions depends on the interplay between magma rheology, exsolution kinetics, and degassing. Magma degassing is governed by the competing effects of vertical transport within the conduit and the lateral flux of gas out of the conduit (Diller et al., 2006; Jaupart and Allegre, 1991). We combine a simplified treatment of these degassing processes with thermodynamic modeling to examine the conditions present at Mount St. Helens during the spine extruding eruption from 2004 to 2008. We find that two parameters are primarily responsible for controlling the eruptive style: the magma chamber temperature, and a dimensionless parameter that gauges the efficiency of lateral degassing. Together, these parameters determine whether and where magma can solidify at depth to form a dense solid plug that is gradually extruded as a volcanic spine. We show that the small (50 oC) decrease in magma chamber temperature between eruptive activity in the 1980s and that of 2004-2008, combined with a modest increase in degassing efficiency associated with lower volumetric flux, can explain the observed change in erupted material from viscous lava flows to solidified spines. More generally, we suggest that similar threshold behavior may explain observed abrupt transitions in effusive eruptive styles at other intermediate composition volcanoes. Finally, we extrapolate our results to suggest that the increase in degassing efficiency accompanying decreasing magma supply rates may have caused the transition from explosive to effusive activity in late 1980.

  2. Age-related changes in biomechanical properties of transgenic porcine pulmonary and aortic conduits

    International Nuclear Information System (INIS)

    Wilczek, Piotr; Malota, Zbigniew; Lesiak, Anna; Niemiec-Cyganek, Aleksandra; Kubin, Barbara; Nozynski, Jerzy; Mzyk, Aldona; Gramatyka, Michalina; Slomski, Ryszard; Wilczek, Grazyna; Opiela, Jolanta

    2014-01-01

    The limitations associated with conventional valve prosthesis have led to a search for alternatives. One potential approach is tissue engineering. Most tissue engineering studies have described the biomechanical properties of heart valves derived from adult pigs. However, because one of the factors affecting the function of valve prosthesis after implantation is appropriate sizing for a given patient, it is important to evaluate the usefulness of a heart valve given the donor animal’s weight and age. The aim of this study was to evaluate how the age of a pig can influence the biomechanical and hemodynamical properties of porcine heart valve prosthesis after acellularization. Acellular porcine aortic and pulmonary valve conduits were used. Hearts were harvested from animals differing in weight and age. The biomechanical properties of the valves were then characterized using a uniaxial tensile test. Moreover, computer simulations based on the finite element method (FEM) were used to study the influence of biomechanical properties on the hemodynamic conditions. Studying biomechanical and morphological changes in porcine heart valve conduits according to the weight and age of the animals can be valuable for developing age-targeted therapy using tissue engineering techniques. (paper)

  3. Experimental study on scale removal from special-shaped conduits through underwater electrical discharge

    International Nuclear Information System (INIS)

    Cao, Y; Wang, Z Q; Li, G F; Wu, Y; Zhou, J J

    2013-01-01

    Underwater electrical discharge technology is an innovative technique that can be used to enhance the stress intensity of water and improve the load addition. The technique enlarges the section area and compresses the surrounding water using a high-powered shock wave, which is induced by an underwater electrical discharge. This paper investigates the effectiveness of scale removal for special-shaped conduits employing underwater electrical discharge. Experimental results show that the pressure wave generated by underwater electrical discharge is capable of eliminating scale in special-shaped conduits. The data indicates that when the capacitance of the parallel-pulsed capacitors was 4 μF, the high pulsed power voltage was 33 kV and the primary discharge gap was 48 mm, the result of scale removal was remarkable. In laboratory tests, the scale of special equipment was removed to a great extent by this method. Because of its effectiveness and low cost, this method improves the practice and extends the lifetime of such equipment, and thus has potential application and economic value.

  4. Rapid prototyping of a double-layer polyurethane-collagen conduit for peripheral nerve regeneration.

    Science.gov (United States)

    Cui, Tongkui; Yan, Yongnian; Zhang, Renji; Liu, Li; Xu, Wei; Wang, Xiaohong

    2009-03-01

    A new technique for preparing double-layer polyurethane (PU)-collagen nerve conduits for peripheral nerve repair via a double-nozzle, low-temperature, deposition manufacturing (DLDM) system has been developed. The DLDM system is based on a digital prototyping approach, and uses a combination of thermally induced phase separation and freeze-drying. With this system, two kinds of biomaterials with different properties can be combined to produce scaffold structures with good biocompatibility in the inner layer and with the desired mechanical strength protruded by the outer. The forming precision is high, the wall thickness can be controlled, and a tight connection between the two layers can be achieved. The effects of changing the processing parameters and the material temperature on the structure of the scaffolds have been investigated. Additionally, the effect of material concentration on the mechanical strength and hydrophilic properties of the scaffolds has also been studied. Ideal peripheral nerve repair conduits, comprising an outer microporous layer of PU and internal oriented filaments of collagen, have been manufactured through optimizing the processing parameters and the biomaterial concentrations.

  5. Control of Target Molecular Recognition in a Small Pore Space with Biomolecule-Recognition Gating Membrane.

    Science.gov (United States)

    Okuyama, Hiroto; Oshiba, Yuhei; Ohashi, Hidenori; Yamaguchi, Takeo

    2018-05-01

    A biomolecule-recognition gating membrane, which introduces thermosensitive graft polymer including molecular recognition receptor into porous membrane substrate, can close its pores by recognizing target biomolecule. The present study reports strategies for improving both versatility and sensitivity of the gating membrane. First, the membrane is fabricated by introducing the receptor via a selectively reactive click reaction improving the versatility. Second, the sensitivity of the membrane is enhanced via an active delivering method of the target molecules into the pores. In the method, the tiny signal of the target biomolecule is amplified as obvious pressure change. Furthermore, this offers 15 times higher sensitivity compared to the previously reported passive delivering method (membrane immersion to sample solution) with significantly shorter recognition time. The improvement will aid in applying the gating membrane to membrane sensors in medical fields. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Respiratory gating and multi field technique radiotherapy for esophageal cancer

    International Nuclear Information System (INIS)

    Ohta, Atsushi; Kaidu, Motoki; Tanabe, Satoshi

    2017-01-01

    To investigate the effects of a respiratory gating and multi field technique on the dose-volume histogram (DVH) in radiotherapy for esophageal cancer. Twenty patients who underwent four-dimensional computed tomography for esophageal cancer were included. We retrospectively created the four treatment plans for each patient, with or without the respiratory gating and multi field technique: No gating-2-field, No gating-4-field, Gating-2-field, and Gating-4-field plans. We compared the DVH parameters of the lung and heart in the No gating-2-field plan with the other three plans.Result In the comparison of the parameters in the No gating-2-field plan, there are significant differences in the Lung V 5Gy , V 20Gy , mean dose with all three plans and the Heart V 25Gy -V 40Gy with Gating-2-field plan, V 35Gy , V 40Gy , mean dose with No Gating-4-field plan and V 30Gy -V 40Gy , and mean dose with Gating-4-field plan. The lung parameters were smaller in the Gating-2-field plan and larger in the No gating-4-field and Gating-4-field plans. The heart parameters were all larger in the No gating-2-field plan. The lung parameters were reduced by the respiratory gating technique and increased by the multi field technique. The heart parameters were reduced by both techniques. It is important to select the optimal technique according to the risk of complications. (author)

  7. 2010 ARRA Lidar: Golden Gate (CA)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Golden Gate LiDAR Project is a cooperative project sponsored by the US Geological Survey (USGS) and San Francisco State University (SFSU) that has resulted in...

  8. Synthesizing biomolecule-based Boolean logic gates.

    Science.gov (United States)

    Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

    2013-02-15

    One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, and hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications.

  9. Extending Double Optical Gating to the Midinfrared

    Science.gov (United States)

    Gorman, Timothy; Camper, Antoine; Agostini, Pierre; Dimauro, Louis

    2015-05-01

    In the past decade there has been great interest in creating broadband isolated attosecond pulses (IAPs). Primarily these IAPs have been generated using Ti:Sapphire 800nm short pulses, namely through spatiotemporal gating with the attosecond lighthouse technique, amplitude gating, polarization gating, and double optical gating (DOG). Here we present theoretical calculations and experimental investigations into extending DOG to using a 2 μm driving wavelength, the benefits of which include extended harmonic cutoff and longer input driving pulse durations. It is proposed that broadband IAPs with cutoffs extending up to 250 eV can be generated in Argon by using >30 fs pulses from the passively-CEP stabilized 2 μm idler out of an optical parametric amplifier combined with a collinear DOG experimental setup.

  10. Golden Gate and Pt. Reyes Acoustic Detections

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains detections of acoustic tagged fish from two general locations: Golden Gate (east and west line) and Pt. Reyes. Several Vemco 69khz acoustic...

  11. Synthesizing Biomolecule-based Boolean Logic Gates

    Science.gov (United States)

    Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

    2012-01-01

    One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications. PMID:23526588

  12. Active gated imaging in driver assistance system

    Science.gov (United States)

    Grauer, Yoav

    2014-04-01

    In this paper, we shall present the active gated imaging system (AGIS) in relation to the automotive field. AGIS is based on a fast-gated camera and pulsed illuminator, synchronized in the time domain to record images of a certain range of interest. A dedicated gated CMOS imager sensor and near infra-red (NIR) pulsed laser illuminator, is presented in this paper to provide active gated technology. In recent years, we have developed these key components and learned the system parameters, which are most beneficial to nighttime (in all weather conditions) driving in terms of field of view, illumination profile, resolution, and processing power. We shall present our approach of a camera-based advanced driver assistance systems (ADAS) named BrightEye™, which makes use of the AGIS technology in the automotive field.

  13. Gating-by-rotation: a solution to the problem of intratreatment motion in helical tomotherapy

    International Nuclear Information System (INIS)

    Kapatoes, J.M.; Olivera, G.H.; Schloesser, E.A.; Pearson, D.W.; Balog, J.P.; Ruchala, K.J.; Schmidt, R.; Reckwerdt, P.J.; Mehta, M.P.; Mackie, T.R.

    2001-01-01

    Purpose: To assess the feasibility of addressing intratreatment motion issues in helical tomotherapy by gating the treatments by rotation. Intratreatment motion is a problem common to all IMRT techniques. Traditional methods of gating in conformal radiotherapy and some forms of IMRT are not applicable to helical tomotherapy due to the continuous rotation of the gantry. An alternative method is presented. Materials and Methods: Rotation-gating in helical tomotherapy is the process in which one rotation of treatment is immediately followed by a rotation of non-treatment. This on-off strategy is repeated for the full treatment volume. During the treatment rotations, the patient is required to hold their breath while the intensity-modulated fan beam deposits dose. For the non-treatment rotations, the patient is allowed to breathe freely as all leaves of the MLC will be closed, the accelerator disabled, or both. The couch indexes normally for treatment rotations and holds the patient stationary during non-treatment rotations. An investigation was conducted to assess the feasibility of rotation-gating. Film was placed between two hemispheres of a water phantom and a continuous helical delivery was carried out with all leaves opened. The film was replaced and another treatment was performed employing rotation-gating. The two films were compared to assess the process. The films were irradiated to dose levels within the linear region of the film response curve (maximum film dose ∼35 cGy). Films were also acquired with all leaves closed to quantify leakage dose through the collimation systems. Results: Central profiles for the inferior-superior direction (parallel to the direction of translation) for both films are displayed in Figure 1. The profiles agree very well, illustrating that a rotation-gated treatment closely mimics a continuous helical delivery. The only significant discrepancy lay in the tails of the profiles: a higher film dose is seen for the rotation-gated

  14. Systematic errors in respiratory gating due to intrafraction deformations of the liver

    International Nuclear Information System (INIS)

    Siebenthal, Martin von; Szekely, Gabor; Lomax, Antony J.; Cattin, Philippe C.

    2007-01-01

    This article shows the limitations of respiratory gating due to intrafraction deformations of the right liver lobe. The variability of organ shape and motion over tens of minutes was taken into account for this evaluation, which closes the gap between short-term analysis of a few regular cycles, as it is possible with 4DCT, and long-term analysis of interfraction motion. Time resolved MR volumes (4D MR sequences) were reconstructed for 12 volunteers and subsequent non-rigid registration provided estimates of the 3D trajectories of points within the liver over time. The full motion during free breathing and its distribution over the liver were quantified and respiratory gating was simulated to determine the gating accuracy for different gating signals, duty cycles, and different intervals between patient setup and treatment. Gating effectively compensated for the respiratory motion within short sequences (3 min), but deformations, mainly in the anterior inferior part (Couinaud segments IVb and V), led to systematic deviations from the setup position of more than 5 mm in 7 of 12 subjects after 20 min. We conclude that measurements over a few breathing cycles should not be used as a proof of accurate reproducibility of motion, not even within the same fraction, if it is longer than a few minutes. Although the diaphragm shows the largest magnitude of motion, it should not be used to assess the gating accuracy over the entire liver because the reproducibility is typically much more limited in inferior parts. Simple gating signals, such as the trajectory of skin motion, can detect the exhalation phase, but do not allow for an absolute localization of the complete liver over longer periods because the drift of these signals does not necessarily correlate with the internal drift

  15. Numerical solution for gate induced vibration due to under flow cavitation

    International Nuclear Information System (INIS)

    Sadrnezhad, S. A.

    2001-01-01

    Among the many forces to which hydraulic structures are exposed to, the forces induced by cavitation incident are of typical hydrodynamic unknown forces. The aim of this study is to define these forces as coupled fluid-structure interaction under two dynamic effects. The first dynamic effect which incorporates facilities for dealing with cavitation fluid is based on the appearance and bursting of vapor bubbles. The second hydrodynamic effect is dynamic excitation mechanism of the structure. In fluid-structure interaction, both the structure behavior and fluid are considered linear. Fluids can take some tension the extent of which depends on concentration and size of micro bubbles present; nevertheless, if the absolute pressure drops to a value close to the vapor pressure of the fluid, bubbles are formed and cavitation phenomena occurs. In this paper a fixed-wheel gate under the head pressure of a reservoir is considered to be affected by under flow cavitation. Normally, partially opened gates induce energy dissipation resulting in high turbulence, causing negative pressure and cavitation at the back and this exits the gate vibration. Moreover, there are several mechanisms which may cause heavy, self-excited vibration. According to the proposed method, a time function presenting the oscillation and pressure fluctuation in the vicinity of gate lip is estimated. This estimation is based on the parameters obtained from a two dimensional solution of flow under the gate lip. Accordingly, periodic time variable nodal forces are calculated and applied to gate lip element nodes. A transient dynamic solution of the gate, while its lip is sustaining nodal forces is estimated as time function. The results for the most server modal deformation of the structure time history of some critical elements and variation of equivalent force versus time are presented

  16. School Closings in Philadelphia

    Science.gov (United States)

    Jack, James; Sludden, John

    2013-01-01

    In 2012, the School District of Philadelphia closed six schools. In 2013, it closed 24. The closure of 30 schools has occurred amid a financial crisis, headlined by the district's $1.35 billion deficit. School closures are one piece of the district's plan to cut expenditures and close its budget gap. The closures are also intended to make…

  17. Dual-gated volumetric modulated arc therapy

    International Nuclear Information System (INIS)

    Fahimian, Benjamin; Wu, Junqing; Wu, Huanmei; Geneser, Sarah; Xing, Lei

    2014-01-01

    Gated Volumetric Modulated Arc Therapy (VMAT) is an emerging radiation therapy modality for treatment of tumors affected by respiratory motion. However, gating significantly prolongs the treatment time, as delivery is only activated during a single respiratory phase. To enhance the efficiency of gated VMAT delivery, a novel dual-gated VMAT (DG-VMAT) technique, in which delivery is executed at both exhale and inhale phases in a given arc rotation, is developed and experimentally evaluated. Arc delivery at two phases is realized by sequentially interleaving control points consisting of MUs, MLC sequences, and angles of VMAT plans generated at the exhale and inhale phases. Dual-gated delivery is initiated when a respiration gating signal enters the exhale window; when the exhale delivery concludes, the beam turns off and the gantry rolls back to the starting position for the inhale window. The process is then repeated until both inhale and exhale arcs are fully delivered. DG-VMAT plan delivery accuracy was assessed using a pinpoint chamber and diode array phantom undergoing programmed motion. DG-VMAT delivery was experimentally implemented through custom XML scripting in Varian’s TrueBeam™ STx Developer Mode. Relative to single gated delivery at exhale, the treatment time was improved by 95.5% for a sinusoidal breathing pattern. The pinpoint chamber dose measurement agreed with the calculated dose within 0.7%. For the DG-VMAT delivery, 97.5% of the diode array measurements passed the 3%/3 mm gamma criterion. The feasibility of DG-VMAT delivery scheme has been experimentally demonstrated for the first time. By leveraging the stability and natural pauses that occur at end-inspiration and end-exhalation, DG-VMAT provides a practical method for enhancing gated delivery efficiency by up to a factor of two

  18. Pericardial tissue valves and Gore-Tex conduits as an alternative for right ventricular outflow tract replacement in children.

    Science.gov (United States)

    Allen, Bradley S; El-Zein, Chawki; Cuneo, Betina; Cava, Joseph P; Barth, Mary Jane; Ilbawi, Michel N

    2002-09-01

    There is still no perfect conduit for reconstruction of the right ventricular outflow tract (RVOT) in children. Homografts are not always available in the appropriate size, and degenerate in a few years. This study evaluates the pericardial valve with Gore-Tex conduit as an alternative for RVOT construction. From January 1, 1993, to September 30, 1999, a pericardial tissue valve was inserted in all patients undergoing RVOT reconstruction or pulmonary valve replacement (PVR) who were large enough to accommodate a tissue valve. In patients without a native main pulmonary artery, a new technique was used to construct an RV-PA conduit out of a flat sheet of Gore-Tex, as Dacron frequently leads to stenosis. Data were collected by retrospective review, follow-up echocardiograms, and assessment by a single cardiologist. There were 48 patients, 22 undergoing a PVR alone and 26 a RV-PA valved Gore-Tex conduit. Diagnosis included tetralogy of Fallot (n = 25); truncus arteriosis (n = 9); ventricular septal defect with PA (n = 5); DORV (n = 4); D-TGA with PS (n = 2); and 1 each IAA with sub AS, VSD with PI, and PS s/p Ross procedure. Patient age ranged from 3 to 33 years and 98% were reoperations. The valve sizes ranged from 19 to 33 mm and the median hospital length of stay was 4 days. There were 2 (4.2%) perioperative and 1 (2.1%) late deaths, none related to the valve or Gore-Tex conduit. At a follow-up of 15 to 86 months (mean 43 +/- 16 months), all remaining 45 patients are New York Heart Association class I, all valves are functional, and no patient has required valve or conduit replacement or revision; more importantly, echocardiogram revealed no significant valve or conduit stenosis (mean gradient 16 +/- 8 mm Hg) and no evidence of regurgitation or structural degeneration. A pericardial tissue valve and Gore-Tex conduit provides a reliable alternative for RVOT reconstruction in pediatric patients. It is readily available, molds in the limited retrosternal space, and

  19. VKCDB: Voltage-gated potassium channel database

    Directory of Open Access Journals (Sweden)

    Gallin Warren J

    2004-01-01

    Full Text Available Abstract Background The family of voltage-gated potassium channels comprises a functionally diverse group of membrane proteins. They help maintain and regulate the potassium ion-based component of the membrane potential and are thus central to many critical physiological processes. VKCDB (Voltage-gated potassium [K] Channel DataBase is a database of structural and functional data on these channels. It is designed as a resource for research on the molecular basis of voltage-gated potassium channel function. Description Voltage-gated potassium channel sequences were identified by using BLASTP to search GENBANK and SWISSPROT. Annotations for all voltage-gated potassium channels were selectively parsed and integrated into VKCDB. Electrophysiological and pharmacological data for the channels were collected from published journal articles. Transmembrane domain predictions by TMHMM and PHD are included for each VKCDB entry. Multiple sequence alignments of conserved domains of channels of the four Kv families and the KCNQ family are also included. Currently VKCDB contains 346 channel entries. It can be browsed and searched using a set of functionally relevant categories. Protein sequences can also be searched using a local BLAST engine. Conclusions VKCDB is a resource for comparative studies of voltage-gated potassium channels. The methods used to construct VKCDB are general; they can be used to create specialized databases for other protein families. VKCDB is accessible at http://vkcdb.biology.ualberta.ca.

  20. Ionic screening effect on low-frequency drain current fluctuations in liquid-gated nanowire FETs

    International Nuclear Information System (INIS)

    Lu, Ming-Pei; Vire, Eric; Montès, Laurent

    2015-01-01

    The ionic screening effect plays an important role in determining the fundamental surface properties within liquid–semiconductor interfaces. In this study, we investigated the characteristics of low-frequency drain current noise in liquid-gated nanowire (NW) field effect transistors (FETs) to obtain physical insight into the effect of ionic screening on low-frequency current fluctuation. When the NW FET was operated close to the gate voltage corresponding to the maximum transconductance, the magnitude of the low-frequency noise for the NW exposed to a low-ionic-strength buffer (0.001 M) was approximately 70% greater than that when exposed to a high-ionic-strength buffer (0.1 M). We propose a noise model, considering the charge coupling efficiency associated with the screening competition between the electrolyte buffer and the NW, to describe the ionic screening effect on the low-frequency drain current noise in liquid-gated NW FET systems. This report not only provides a physical understanding of the ionic screening effect behind the low-frequency current noise in liquid-gated FETs but also offers useful information for developing the technology of NW FETs with liquid-gated architectures for application in bioelectronics, nanosensors, and hybrid nanoelectronics. (paper)

  1. RNA polymerase gate loop guides the nontemplate DNA strand in transcription complexes.

    Science.gov (United States)

    NandyMazumdar, Monali; Nedialkov, Yuri; Svetlov, Dmitri; Sevostyanova, Anastasia; Belogurov, Georgiy A; Artsimovitch, Irina

    2016-12-27

    Upon RNA polymerase (RNAP) binding to a promoter, the σ factor initiates DNA strand separation and captures the melted nontemplate DNA, whereas the core enzyme establishes interactions with the duplex DNA in front of the active site that stabilize initiation complexes and persist throughout elongation. Among many core RNAP elements that participate in these interactions, the β' clamp domain plays the most prominent role. In this work, we investigate the role of the β gate loop, a conserved and essential structural element that lies across the DNA channel from the clamp, in transcription regulation. The gate loop was proposed to control DNA loading during initiation and to interact with NusG-like proteins to lock RNAP in a closed, processive state during elongation. We show that the removal of the gate loop has large effects on promoter complexes, trapping an unstable intermediate in which the RNAP contacts with the nontemplate strand discriminator region and the downstream duplex DNA are not yet fully established. We find that although RNAP lacking the gate loop displays moderate defects in pausing, transcript cleavage, and termination, it is fully responsive to the transcription elongation factor NusG. Together with the structural data, our results support a model in which the gate loop, acting in concert with initiation or elongation factors, guides the nontemplate DNA in transcription complexes, thereby modulating their regulatory properties.

  2. Ultraclean single, double, and triple carbon nanotube quantum dots with recessed Re bottom gates

    Science.gov (United States)

    Jung, Minkyung; Schindele, Jens; Nau, Stefan; Weiss, Markus; Baumgartner, Andreas; Schoenenberger, Christian

    2014-03-01

    Ultraclean carbon nanotubes (CNTs) that are free from disorder provide a promising platform to manipulate single electron or hole spins for quantum information. Here, we demonstrate that ultraclean single, double, and triple quantum dots (QDs) can be formed reliably in a CNT by a straightforward fabrication technique. The QDs are electrostatically defined in the CNT by closely spaced metallic bottom gates deposited in trenches in Silicon dioxide by sputter deposition of Re. The carbon nanotubes are then grown by chemical vapor deposition (CVD) across the trenches and contacted using conventional electron beam lithography. The devices exhibit reproducibly the characteristics of ultraclean QDs behavior even after the subsequent electron beam lithography and chemical processing steps. We demonstrate the high quality using CNT devices with two narrow bottom gates and one global back gate. Tunable by the gate voltages, the device can be operated in four different regimes: i) fully p-type with ballistic transport between the outermost contacts (over a length of 700 nm), ii) clean n-type single QD behavior where a QD can be induced by either the left or the right bottom gate, iii) n-type double QD and iv) triple bipolar QD where the middle QD has opposite doping (p-type). Research at Basel is supported by the NCCR-Nano, NCCR-QIST, ERC project QUEST, and FP7 project SE2ND.

  3. Coordinated movement of cytoplasmic and transmembrane domains of RyR1 upon gating.

    Directory of Open Access Journals (Sweden)

    Montserrat Samsó

    2009-04-01

    Full Text Available Ryanodine receptor type 1 (RyR1 produces spatially and temporally defined Ca2+ signals in several cell types. How signals received in the cytoplasmic domain are transmitted to the ion gate and how the channel gates are unknown. We used EGTA or neuroactive PCB 95 to stabilize the full closed or open states of RyR1. Single-channel measurements in the presence of FKBP12 indicate that PCB 95 inverts the thermodynamic stability of RyR1 and locks it in a long-lived open state whose unitary current is indistinguishable from the native open state. We analyzed two datasets of 15,625 and 18,527 frozen-hydrated RyR1-FKBP12 particles in the closed and open conformations, respectively, by cryo-electron microscopy. Their corresponding three-dimensional structures at 10.2 A resolution refine the structure surrounding the ion pathway previously identified in the closed conformation: two right-handed bundles emerging from the putative ion gate (the cytoplasmic "inner branches" and the transmembrane "inner helices". Furthermore, six of the identifiable transmembrane segments of RyR1 have similar organization to those of the mammalian Kv1.2 potassium channel. Upon gating, the distal cytoplasmic domains move towards the transmembrane domain while the central cytoplasmic domains move away from it, and also away from the 4-fold axis. Along the ion pathway, precise relocation of the inner helices and inner branches results in an approximately 4 A diameter increase of the ion gate. Whereas the inner helices of the K+ channels and of the RyR1 channel cross-correlate best with their corresponding open/closed states, the cytoplasmic inner branches, which are not observed in the K+ channels, appear to have at least as important a role as the inner helices for RyR1 gating. We propose a theoretical model whereby the inner helices, the inner branches, and the h1 densities together create an efficient novel gating mechanism for channel opening by relaxing two right

  4. Experimental sintering of ash at conduit conditions and implications for the longevity of tuffisites

    Science.gov (United States)

    Gardner, James E.; Wadsworth, Fabian B.; Llewellin, Edward W.; Watkins, James M.; Coumans, Jason P.

    2018-03-01

    Escape of gas from magma in the conduit plays a crucial role in mitigating explosivity. Tuffisite veins—ash-filled cracks that form in and around volcanic conduits—represent important gas escape pathways. Sintering of the ash infill decreases its porosity, eventually forming dense glass that is impermeable to gas. We present an experimental investigation of surface tension-driven sintering and associated densification of rhyolitic ash under shallow conduit conditions. Suites of isothermal (700-800 °C) and isobaric H2O pressure (20 and 40 MPa) experiments were run for durations of 5-90 min. Obsidian powders with two different size distributions were used: 1-1600 μm (mean size = 89 μm), and 63-400 μm (mean size = 185 μm). All samples evolved similarly through four textural phases: phase 1—loose and cohesion-less particles; phase 2—particles sintered at contacts and surrounded by fully connected tortuous pore space of up to 40% porosity; phase 3—continuous matrix of partially coalesced particles that contain both isolated spherical vesicles and connected networks of larger, contorted vesicles; phase 4—dense glass with 2-5% fully isolated vesicles that are mainly spherical. Textures evolve faster at higher temperature and higher H2O pressure. Coarse samples sinter more slowly and contain fewer, larger vesicles when fully sintered. We quantify the sintering progress by measuring porosity as a function of experimental run-time, and find an excellent collapse of data when run-time is normalized by the sintering timescale {λ}_s=η \\overline{R}/σ , where η is melt viscosity, \\overline{R} is mean particle radius, and σ is melt-gas surface tension. Because timescales of diffusive H2O equilibration are generally fast compared to those of sintering, the relevant melt viscosity is calculated from the solubility H2O content at experimental temperature and pressure. We use our results to develop a framework for estimating ash sintering rates under shallow

  5. [Electrophysiological study on rat conduit pulmonary artery smooth muscle cells under normoxia and acute hypoxia].

    Science.gov (United States)

    Hu, Ying; Zou, Fei; Cai, Chun-Qing; Wu, Hang-Yu; Yun, Hai-Xia; Chen, Yun-Tian; Jin, Guo-En; Ge, Ri-Li

    2006-10-25

    The present study was designed to investigate the electrophysiological characteristics of rat conduit pulmonary artery smooth muscle cells (PASMCs) and the response to acute hypoxia. PASMCs of the 1st to 2nd order branches in the conduit pulmonary arteries were obtained by enzymatic isolation. The PASMCs were divided into acute hypoxia preconditioned group and normoxia group. Hypoxia solutions were achieved by bubbling with 5% CO2 plus 95% N2 for at least 30 min before cell perfusion. Potassium currents were compared between these two groups using whole-cell patch clamp technique. The total outward current of PASMCs was measured under normoxia condition when iBTX [specific blocking agent of large conductance Ca-activated K(+) (BK(Ca)) channel] and 4-AP [specific blocking agent of delayed rectifier K(+) (K(DR)) channel] were added consequently into bath solution. PASMCs were classified into three types according to their size, shape and electrophysiological characteristics. Type I cells are the smallest with spindle shape, smooth surface and discrete perinuclear bulge. Type II cells show the biggest size with banana-like appearance. Type III cells have the similar size with type I, and present intermediary shape between type I and type II. iBTX had little effect on the total outward current in type I cells, while 4-AP almost completely blocked it. Most of the total outward current in type II cells was inhibited by iBTX, and the remaining was sensitive to 4-AP. In type III cells, the total outward current was sensitive to both iBTX and 4-AP. Acute hypoxia reduced the current in all three types of cells: (1614.8+/-62.5) pA to (892.4+/-33.6) pA for type I cells (Ppotassium current and improves the E(m) in PASMCs. These effects may be involved in the modulation of constriction/relaxation of conduit artery under acute hypoxia. Different distribution of K(DR) and BK(Ca) channels in these three types of PASMCs might account for their different constriction

  6. Permeability and 3-D melt geometry in shear-induced high melt fraction conduits

    Science.gov (United States)

    Zhu, W.; Cordonnier, B.; Qi, C.; Kohlstedt, D. L.

    2017-12-01

    Observations of dunite channels in ophiolites and uranium-series disequilibria in mid-ocean ridge basalt suggest that melt transport in the upper mantle beneath mid-ocean ridges is strongly channelized. Formation of high melt fraction conduits could result from mechanical shear, pyroxene dissolution, and lithological partitioning. Deformation experiments (e.g. Holtzman et al., 2003) demonstrate that shear stress causes initially homogeneously distributed melt to segregate into an array of melt-rich bands, flanked by melt-depleted regions. At the same average melt fraction, the permeability of high melt fraction conduits could be orders of magnitude higher than that of their homogenous counterparts. However, it is difficult to determine the permeability of melt-rich bands. Using X-ray synchrotron microtomography, we obtained high-resolution images of 3-dimensional (3-D) melt distribution in a partially molten rock containing shear-induced high melt fraction conduits. Sample CQ0705, an olivine-alkali basalt aggregate with a nominal melt fraction of 4%, was deformed in torsion at a temperature of 1473 K and a confining pressure of 300 MPa to a shear strain of 13.3. A sub-volume of CQ0705 encompassing 3-4 melt-rich bands was imaged. Microtomography data were reduced to binary form so that solid olivine is distinguishable from basalt glass. At a spatial resolution of 160 nm, the 3-D images reveal the shape and connectedness of melt pockets in the melt-rich bands. Thin melt channels formed at grain edges are connected at large melt nodes at grain corners. Initial data analysis shows a clear preferred orientation of melt pockets alignment subparallel to the melt-rich band. We use the experimentally determined geometrical parameters of melt topology to create a digital rock with identical 3-D microstructures. Stokes flow simulations are conducted on the digital rock to obtain the permeability tensor. Using this digital rock physics approach, we determine how deformation

  7. NECL1 coated PLGA as favorable conduits for repair of injured peripheral nerve

    International Nuclear Information System (INIS)

    Xu, Fuben; Zhang, Kun; Lv, Peizhen; Lu, Rongbin; Zheng, Li; Zhao, Jinmin

    2017-01-01

    Restoration of normal neurological function of transected peripheral nerve challenged regenerative medicine and surgery. Previous studies showed that Nectin-like molecule 1 (NECL1) is one of the important adhesion molecules on the axons and Schwann cells is located along the internodes in direct apposition to NECL1. In this study, we fabricated PLGA membrane pre-coated with NECL1, mimicking the natural axons to enhance the adhesion of Schwann cells. Investigation of the cellular response in vitro was performed by detecting cytotoxicity, proliferation, morphology, viability, specific markers and Scanning Electron Microscopy (SEM) of Schwann cells cultured in PLGA. Further, the NECL1-coated PLGA conduits were used for peripheral nerve repair after sciatic nerve defect was constructed. Results showed that PLGA-coated NECL1 enhanced cell proliferation compared with PLGA, as evidenced by MTT analysis, cell viability assay and histological evaluation. RT-PCR results showed that GDNF (glial cell line-derived neurotrophic factor), BDNF (brain-derived neurotrophic factor), CNTF (ciliary neurotrophic factor) and neurotrophic factors of axonal regeneration were highly expressed in PLGA/NECL1 group. S100, which is Schwann cell marker, was also elevated in PLGA-NCEL1 in both mRNA and protein expression as demonstrated by PCR and immunohistochemical examination. Moreover, in vivo study showed that implantation of PLGA/NCEL1 tubes in bridging the nerve defect can significantly improve Schwann cell aggregation and attachment and greatly enhance the functional recovery of nerve regeneration as compared with control and PLGA groups. Therefore, the novel blend of PLGA/NECL1 conduits proved to be promising candidate for tissue engineering scaffold. - Highlights: • A fabricated PLGA tubes pre-coated with Nectin-like molecule 1 (NECL1) strategy for sciatic nerve regeneration is proposed. • The NECL1 coated PLGA can promote Schwann cells adhesion and growth meanwhile maintain the

  8. Preliminary observations of gate valve flow interruption tests, Phase 2

    International Nuclear Information System (INIS)

    Steele, R. Jr.; DeWall, K.G.

    1990-01-01

    This paper presents preliminary observations from the US Nuclear Regulatory Commission/Idaho National Engineering Laboratory Flexible Wedge Gate Valve Qualification and Flow Interruption Test Program, Phase 2. The program investigated the ability of selected boiling water reactor (BWR) process line valves to perform their containment isolation function at high energy pipe break conditions and other more normal flow conditions. The fluid and valve operating responses were measured to provide information concerning valve and operator performance at various valve loadings so that the information could be used to assess typical nuclear industry motor operator sizing equations. Six valves were tested, three 6-in. isolation valves representative of those used in reactor water cleanup systems in BWRs and three 10-in. isolation valves representative of those used in BWR high pressure coolant injection (HPCI) steam lines. The concern with these normally open isolation valves is whether they will close in the event of a downstream pipe break outside of containment. The results of this testing will provide part of the technical insights for NRC efforts regarding Generic Issue 87 (GI-87), Failure of the HPCI Steam Line Without Isolation, which includes concerns about the uncertainties in gate valve motor operator sizing and torque switch settings for these BWR containment isolation valves. As of this writing, the Phase 2 test program has just been completed. Preliminary observations made in the field confirmed most of the results from the Phase 1 test program. All six valves closing in high energy water, high energy steam, and high pressure cold water require more force to close than would be calculated using the typical variables in the standard industry motor operator sizing equations

  9. Respiratory gating in positron emission tomography: A quantitative comparison of different gating schemes

    International Nuclear Information System (INIS)

    Dawood, Mohammad; Buether, Florian; Lang, Norbert; Schober, Otmar; Schaefers, Klaus P

    2007-01-01

    Respiratory gating is used for reducing the effects of breathing motion in a wide range of applications from radiotherapy treatment to diagnostical imaging. Different methods are feasible for respiratory gating. In this study seven gating methods were developed and tested on positron emission tomography (PET) listmode data. The results of seven patient studies were compared quantitatively with respect to motion and noise. (1) Equal and (2) variable time-based gating methods use only the time information of the breathing cycle to define respiratory gates. (3) Equal and (4) variable amplitude-based gating approaches utilize the amplitude of the respiratory signal. (5) Cycle-based amplitude gating is a combination of time and amplitude-based techniques. A baseline correction was applied to methods (3) and (4) resulting in two new approaches: Baseline corrected (6) equal and (7) variable amplitude-based gating. Listmode PET data from seven patients were acquired together with a respiratory signal. Images were reconstructed applying the seven gating methods. Two parameters were used to quantify the results: Motion was measured as the displacement of the heart due to respiration and noise was defined as the standard deviation of pixel intensities in a background region. The amplitude-based approaches (3) and (4) were superior to the time-based methods (1) and (2). The improvement in capturing the motion was more than 30% (up to 130%) in all subjects. The variable time (2) and amplitude (4) methods had a more uniform noise distribution among all respiratory gates compared to equal time (1) and amplitude (3) methods. Baseline correction did not improve the results. Out of seven different respiratory gating approaches, the variable amplitude method (4) captures the respiratory motion best while keeping a constant noise level among all respiratory phases

  10. Combined use of decellularized allogeneic artery conduits with autologous transdifferentiated adipose-derived stem cells for facial nerve regeneration in rats.

    Science.gov (United States)

    Sun, Fei; Zhou, Ke; Mi, Wen-juan; Qiu, Jian-hua

    2011-11-01

    Natural biological conduits containing seed cells have been widely used as an alternative strategy for nerve gap reconstruction to replace traditional nerve autograft techniques. The purpose of this study was to investigate the effects of a decellularized allogeneic artery conduit containing autologous transdifferentiated adipose-derived stem cells (dADSCs) on an 8-mm facial nerve branch lesion in a rat model. After 8 weeks, functional evaluation of vibrissae movements and electrophysiological assessment, retrograde labeling of facial motoneurons and morphological analysis of regenerated nerves were performed to assess nerve regeneration. The transected nerves reconstructed with dADSC-seeded artery conduits achieved satisfying regenerative outcomes associated with morphological and functional improvements which approached those achieved with Schwann cell (SC)-seeded artery conduits, and superior to those achieved with artery conduits alone or ADSC-seeded artery conduits, but inferior to those achieved with nerve autografts. Besides, numerous transplanted PKH26-labeled dADSCs maintained their acquired SC-phenotype and myelin sheath-forming capacity inside decellularized artery conduits and were involved in the process of axonal regeneration and remyelination. Collectively, our combined use of decellularized allogeneic artery conduits with autologous dADSCs certainly showed beneficial effects on nerve regeneration and functional restoration, and thus represents an alternative approach for the reconstruction of peripheral facial nerve defects. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Analytical drain current formulation for gate dielectric engineered dual material gate-gate all around-tunneling field effect transistor

    Science.gov (United States)

    Madan, Jaya; Gupta, R. S.; Chaujar, Rishu

    2015-09-01

    In this work, an analytical drain current model for gate dielectric engineered (hetero dielectric)-dual material gate-gate all around tunnel field effect transistor (HD-DMG-GAA-TFET) has been developed. Parabolic approximation has been used to solve the two-dimensional (2D) Poisson equation with appropriate boundary conditions and continuity equations to evaluate analytical expressions for surface potential, electric field, tunneling barrier width and drain current. Further, the analog performance of the device is studied for three high-k dielectrics (Si3N4, HfO2, and ZrO2), and it has been investigated that the problem of lower ION, can be overcome by using the hetero-gate architecture. Moreover, the impact of scaling the gate oxide thickness and bias variations has also been studied. The HD-DMG-GAA-TFET shows an enhanced ION of the order of 10-4 A. The effectiveness of the proposed model is validated by comparing it with ATLAS device simulations.

  12. Detection of the normal zone with cowound sensors in cable-in conduit conductors

    International Nuclear Information System (INIS)

    Martovetsky, N.N.; Chaplin, M.R.

    1996-01-01

    Tokamaks in the future will use superconducting cable-in-conduit- conductors (CICC) in all poloidal field (PF) and toroidal field (TF) magnets. Conventional quench detection, the measurement of small resistive normal zone voltages ( 4 kV). In the quench detection design for TPX, we have considered several different locations for internal co-wound voltage sensors in the cable cross-section as the primary mechanism to cancel this inductive noise. The Noise Rejection Experiment (NRE) at LLNL has been designed to evaluate which internal locations will produce the best inductive- noise cancellation, and provide us with experimental data for comparison with previously developed theory. The details of the experiments and resulting data are presented and analyzed

  13. Quench detection by fluid dynamic means in cable-in-conduit superconductors

    International Nuclear Information System (INIS)

    Dresner, L.

    1988-01-01

    The tight confinement of the helium in cable-in-conduit superconductors creates protection problems because of the pressure rise that can occur during a quench. But the same pressure rise offers the possibility of a non-electrical means of detecting incipient quenches by monitoring the outflow from the various hydraulic paths of the magnet. If the method is to work, the signal must be large enough to be detected unambiguously at an early time, and must not depend too strongly on the length, Joule power density, or rate of growth of the initial normal zone. This paper explores by calculation the degree to which these conditions can be met. The Westinghouse Large Coil Task coil is used as an example

  14. Le projet de recherche: définition, conduite et réalisation

    OpenAIRE

    Stockinger , Peter

    2013-01-01

    Master; Ce support de séminaire développe brièvement les quatre points suivants: 1) Définition d’un projet de recherche – présentation générale et recommandations. 2) La conduite d’un projet de recherche – présentation générale et recommandations. 3) La réalisation d’un projet de recherche sous forme d’un mémoire - présentation générale et recommandations. 4) Des ressources pour conduire un projet de recherche : ressources enligne et références bibliographiques.

  15. A novel approach to estimate the eruptive potential and probability in open conduit volcanoes.

    Science.gov (United States)

    De Gregorio, Sofia; Camarda, Marco

    2016-07-26

    In open conduit volcanoes, volatile-rich magma continuously enters into the feeding system nevertheless the eruptive activity occurs intermittently. From a practical perspective, the continuous steady input of magma in the feeding system is not able to produce eruptive events alone, but rather surplus of magma inputs are required to trigger the eruptive activity. The greater the amount of surplus of magma within the feeding system, the higher is the eruptive probability.Despite this observation, eruptive potential evaluations are commonly based on the regular magma supply, and in eruptive probability evaluations, generally any magma input has the same weight. Conversely, herein we present a novel approach based on the quantification of surplus of magma progressively intruded in the feeding system. To quantify the surplus of magma, we suggest to process temporal series of measurable parameters linked to the magma supply. We successfully performed a practical application on Mt Etna using the soil CO2 flux recorded over ten years.

  16. Faulting within the Mount St. Helens conduit and implications for volcanic earthquakes

    Science.gov (United States)

    Pallister, John S.; Cashman, Katharine V.; Hagstrum, Jonathan T.; Beeler, Nicholas M.; Moran, Seth C.; Denlinger, Roger P.

    2013-01-01

    The 2004–2008 eruption of Mount St. Helens produced seven dacite spines mantled by cataclastic fault rocks, comprising an outer fault core and an inner damage zone. These fault rocks provide remarkable insights into the mechanical processes that accompany extrusion of degassed magma, insights that are useful in forecasting dome-forming eruptions. The outermost part of the fault core consists of finely comminuted fault gouge that is host to 1- to 3-mm-thick layers of extremely fine-grained slickenside-bearing ultracataclasite. Interior to the fault core, there is an ∼2-m-thick damage zone composed of cataclastic breccia and sheared dacite, and interior to the damage zone, there is massive to flow-banded dacite lava of the spine interior. Structures and microtextures indicate entirely brittle deformation, including rock breakage, tensional dilation, shearing, grain flow, and microfaulting, as well as gas and fluid migration through intergranular pores and fractures in the damage zone. Slickenside lineations and consistent orientations of Riedel shears indicate upward shear of the extruding spines against adjacent conduit wall rocks.Paleomagnetic directions, demagnetization paths, oxide mineralogy, and petrology indicate that cataclasis took place within dacite in a solidified steeply dipping volcanic conduit at temperatures above 500 °C. Low water content of matrix glass is consistent with brittle behavior at these relatively high temperatures, and the presence of tridymite indicates solidification depths of <1 km. Cataclasis was coincident with the eruption’s seismogenic zone at <1.5 km.More than a million small and low-frequency “drumbeat” earthquakes with coda magnitudes (Md) <2.0 and frequencies <5 Hz occurred during the 2004–2008 eruption. Our field data provide a means with which to estimate slip-patch dimensions for shear planes and to compare these with estimates of slip patches based on seismic moments and shear moduli for dacite rock and

  17. Tuning the allosteric regulation of artificial muscarinic and dopaminergic ligand-gated potassium channels by protein engineering of G protein-coupled receptors

    Science.gov (United States)

    Moreau, Christophe J.; Revilloud, Jean; Caro, Lydia N.; Dupuis, Julien P.; Trouchet, Amandine; Estrada-Mondragón, Argel; Nieścierowicz, Katarzyna; Sapay, Nicolas; Crouzy, Serge; Vivaudou, Michel

    2017-01-01

    Ligand-gated ion channels enable intercellular transmission of action potential through synapses by transducing biochemical messengers into electrical signal. We designed artificial ligand-gated ion channels by coupling G protein-coupled receptors to the Kir6.2 potassium channel. These artificial channels called ion channel-coupled receptors offer complementary properties to natural channels by extending the repertoire of ligands to those recognized by the fused receptors, by generating more sustained signals and by conferring potassium selectivity. The first artificial channels based on the muscarinic M2 and the dopaminergic D2L receptors were opened and closed by acetylcholine and dopamine, respectively. We find here that this opposite regulation of the gating is linked to the length of the receptor C-termini, and that C-terminus engineering can precisely control the extent and direction of ligand gating. These findings establish the design rules to produce customized ligand-gated channels for synthetic biology applications. PMID:28145461

  18. Frictional melting dynamics in the upper conduit: A chemical answer to a complex physical question

    Science.gov (United States)

    Henton De Angelis, S.; Lavallee, Y.; Kendrick, J. E.; Hornby, A.; von Aulock, F. W.; Clesham, S.; Hirose, T.; Perugini, D.

    2013-12-01

    During volcanic eruptions the generation of frictional heat along the walls of the shallow conduit leads to melting of the rocks along the slip interface. Frictional melting has previously been described as a process out of thermodynamic equilibrium, but upon slip and mingling of the melt batches, homogeneity can be achieved, and may have an h important rheological control on the dynamics of slip. To test melt homogenization in the frictional melt zones of volcanic conduits we performed constant-rate slip experiments under controlled stress conditions using a high-velocity rotary shear apparatus. Volcanic dome samples from three different volcanoes (Volcán De Colima, Soufrière Hills Volcano and Santiaguito Volcano) were investigated. Each sample was subjected to a stress of 1 MPa and slip rate of 1 m/s. For each sample set 5 experiments were conducted: 1) experiment stopped at the onset of melting; 2) experiment stopped on the formation of a full melt layer; 3) experiment stopped after 5m of slip at steady state conditions; 4) experiment stopped after 10m of slip at steady state conditions; 5) experiment stopped after 15m of slip at steady state conditions. We analyzed the resulting proto-melt zones using micron sized X-ray spectroscopy in the high-brightness synchrotron beamline I18 (at Diamond Light Source UK). Particular focus was given to the concentration variance analysis of Rare Earth Elements as their mobilities can be used to precisely quantify the degree and timescale of homogenisation involved during frictional melting. This study refines our understanding of the chemical process of melting and mixing which carry important consequences for the rheological control on the physical dynamics of slip.

  19. Fabrication of nerve guidance conduit with luminal filler as scaffold for peripheral nerve repair

    International Nuclear Information System (INIS)

    Aranilla, Charito T.; Wach, Rodoslaw; Ulanski, Piotr

    2015-01-01

    Peripheral nerve injury is a serious health concern for society, affecting trauma patients, many of whom acquire life-long disability. The gold standard of treatment for peripheral nerve injury is the use of nerve grafts, wherein nerve autograft or allograft is used to bridge the gap in the damaged nerve. Nerve guidance conduits (NGCs) are an attractive alternative to nerve autografts for aiding in the regeneration of peripheral nerve tissue. NGCs are small cylinders or tubes composed of either natural or synthetic biomaterials that are used to axon regeneration. The ends of the damaged nerve are inserted into either end of the cylinder and the NGC acts both as a connecting bridge for the severed nerve ends as well as a protective shelter for the regenerating nerve. This study aims at fabricating nerve guidance conduits with luminal structure based on synthetic biodegradable and biocompatible polymers such as poly (trimethylene carbonate ) (PTMC), poly (lactic acid) (PLA) and poly (caprolactone) (PCL). Initial base materials for fabrication were PLA acid tubes compared to PCL tubes when prepared by spray and dip-coating methods. The morphology of the tubes where examined by SEM and results showed better porosity of PLA acid tubes compared to PCL tubes when prepared by spraying technique. Poly(lactic acid) was then blended with poly(trimethylene carbonate) at a ratio of 1:4 (5% total polymer content) for further fabrication. Electron beam radiation (25 and 50 kGy) was employed for sterilization and the changes in properties induced by irradiation in comprising polymers were evaluated. The wettability, mechanical thermal properties were not significantly changed by irradiation.In a separate experiment, synthesis of carboxymethyl chitosan hydrogel crosslinked by electron beam radiation was studied to create a luminal filler for PTMC-PLA tubes. Based on proper viscosity of solution before crosslinking, sufficient gel fraction and swelling, 10% w/v concentration of

  20. Pockets, conduits, channels, and plumes: links to volcanism and orogeny in the rollback dominated western Mediterranean

    Science.gov (United States)

    Miller, Meghan S.; Sun, Daoyuan; O'Driscoll, Leland; Becker, Thorsten W.; Holt, Adam; Diaz, Jordi; Thomas, Christine

    2015-04-01

    Detailed mantle and lithospheric structure from the Canary Islands to Iberia have been imaged with data from recent temporary deployments and select permanent stations from over 300 broadband seismometers. The stations extended across Morocco and Spain as part of the PICASSO, IberArray, and Morocco-Münster experiments. We present results from S receiver functions (SRF), shear wave splitting, waveform modeling, and geodynamic models that help constrain the tectonic evolution of the westernmost Mediterranean, including orogenesis of the Atlas Mountains and occurrence of localized alkaline volcanism. Our receiver function images, in agreement with previous geophysical modeling, show that the lithosphere is thin (~65 km) beneath the Atlas, but thickens (~100 km) over a very short length scale at the flanks of the mountains. We find that these dramatic changes in lithospheric thickness also correspond to dramatic decreases in delay times inferred from S and SKS splitting observations of seismic anisotropy. Pockets and conduits of low seismic velocity material below the lithosphere extend along much of the Atlas to Southern Spain and correlate with the locations of Pliocene-Quaternary magmatism. Waveform analysis from the USC linear seismic array across the Atlas Mountains constrains the position, shape, and physical characteristics of one localized, low velocity conduit that extends from the uppermost mantle (~200 km depth) up to the volcanoes in the Middle Atlas. The shape, position and temperature of these seismically imaged low velocity anomalies, topography of the base of the lithosphere, morphology of the subducted slab beneath the Alboran Sea, position of the West African Craton and correlation with mantle flow inferred from shear wave splitting suggest that the unusually high topography of the Atlas Mountains and isolated recent volcanics are due to active mantle support that may be from material channeled from the Canary Island plume.

  1. Radial Artery as a Coronary Artery Bypass Conduit: 20-Year Results.

    Science.gov (United States)

    Gaudino, Mario; Tondi, Paolo; Benedetto, Umberto; Milazzo, Valentina; Flore, Roberto; Glieca, Franco; Ponziani, Francesca Romana; Luciani, Nicola; Girardi, Leonard N; Crea, Filippo; Massetti, Massimo

    2016-08-09

    There is a lack of evidence for the choice of the second conduit in coronary surgery. The radial artery (RA) is a possible option, but few data on very-long-term outcomes exist. This study describes 20-year results of RA grafts used for coronary artery bypass grafting and the effects of RA removal on forearm circulation. We report the results of the prospective 20-year follow-up of the first 100 consecutive patients who received the RA as a coronary bypass conduit at our institution. Follow-up was 100% complete. There were 64 deaths, 23 (35.9%) from cardiovascular causes. Kaplan-Meier 20-year survival was 31%. Of the 36 survivors, 33 (91.6%) underwent RA graft control at a mean of 19.0 ± 2.5 years after surgery. The RA was found to be patent in 24 cases (84.8% patency). In the overall population, probability of graft failure at 20 years was 19.0 ± 0.2% for the left internal thoracic artery (ITA), 25.0 ± 0.2% for the RA, and 55.0 ± 0.2% for the saphenous vein (p = 0.002 for RA vs. saphenous vein, 0.11 for RA vs. ITA, and p 90%, but not location of distal anastomosis, significantly influenced long-term RA graft patency. No patients reported hand or forearm symptoms. The ulnar artery diameter was increased in the operated arm (2.44 ± 0.43 mm vs. 2.01 ± 0.47 mm; p 90% stenosis. RA harvesting does not lead to hand or forearm symptoms, even at a very-long-term follow-up. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  2. Theory and modelling of quench in cable-in-conduit superconducting magnets

    International Nuclear Information System (INIS)

    Shajii, A.

    1994-04-01

    A new simple, self consistent theoretical model is presented that describes the phenomena of quench propagation in Cable-In-Conduit superconducting magnets. The model (Quencher) circumvents many of the difficulties associated with obtaining numerical solutions in more general existing models. Specifically, a factor of 30-50 is gained in CPU time over the general, explicit time dependent codes used to study typical quench events. The corresponding numerical implementation of the new model is described and the numerical results are shown to agree very well with those of the more general models, as well as with experimental data. Further, well justified approximations lead to the MacQuench model that is shown to be very accurate and considerably more efficient than the Quencher model. The MacQuench code is suitable for performing quench studies on a personal computer, requiring only several minutes of CPU time. In order to perform parametric studies on new conductor designs it is required to utilize a model such as MacQuench because of the high computational efficiency of this model. Finally, a set of analytic solutions for the problem of quench propagation in Cable-In-Conduit Conductors is presented. These analytic solutions represent the first such results that remain valid for the long time scales of interest during a quench process. The assumptions and the resulting simplifications that lead to the analytic solutions are discussed, and the regimes of validity of the various approximations are specified. The predictions of the analytic results are shown to be in very good agreement with numerical as well as experimental results. Important analytic scaling relations are verified by such comparisons, and the consequences of some of these scalings on currently designed superconducting magnets are discussed

  3. Tissue-engineered spiral nerve guidance conduit for peripheral nerve regeneration.

    Science.gov (United States)

    Chang, Wei; Shah, Munish B; Lee, Paul; Yu, Xiaojun

    2018-06-01

    Recently in peripheral nerve regeneration, preclinical studies have shown that the use of nerve guidance conduits (NGCs) with multiple longitudinally channels and intra-luminal topography enhance the functional outcomes when bridging a nerve gap caused by traumatic injury. These features not only provide guidance cues for regenerating nerve, but also become the essential approaches for developing a novel NGC. In this study, a novel spiral NGC with aligned nanofibers and wrapped with an outer nanofibrous tube was first developed and investigated. Using the common rat sciatic 10-mm nerve defect model, the in vivo study showed that a novel spiral NGC (with and without inner nanofibers) increased the successful rate of nerve regeneration after 6 weeks recovery. Substantial improvements in nerve regeneration were achieved by combining the spiral NGC with inner nanofibers and outer nanofibrous tube, based on the results of walking track analysis, electrophysiology, nerve histological assessment, and gastrocnemius muscle measurement. This demonstrated that the novel spiral NGC with inner aligned nanofibers and wrapped with an outer nanofibrous tube provided a better environment for peripheral nerve regeneration than standard tubular NGCs. Results from this study will benefit for future NGC design to optimize tissue-engineering strategies for peripheral nerve regeneration. We developed a novel spiral nerve guidance conduit (NGC) with coated aligned nanofibers. The spiral structure increases surface area by 4.5 fold relative to a tubular NGC. Furthermore, the aligned nanofibers was coated on the spiral walls, providing cues for guiding neurite extension. Finally, the outside of spiral NGC was wrapped with randomly nanofibers to enhance mechanical strength that can stabilize the spiral NGC. Our nerve histological data have shown that the spiral NGC had 50% more myelinated axons than a tubular structure for nerve regeneration across a 10 mm gap in a rat sciatic nerve

  4. Aptitude visuelle à la conduite automobile: exemple des candidats au permis de conduire à Libreville

    Science.gov (United States)

    Souhail, Hassane; Assoumou, Prudence; Birinda, Hilda; Mengome, Emmanuel Mve

    2015-01-01

    L'objectif était d’évaluer l'aptitude visuelle à la conduite automobile des candidats au permis de conduire à Libreville. Il s'agissait d'une étude transversale, descriptive et analytique, qui s'est déroulée à Libreville pendant la période du 4 avril 2012 au 14 juillet 2012 (soit 4 mois et 10 jours). La population d’étude concernait les candidats soumis aux épreuves d'obtention du permis de conduire. Nous avons inclus dans notre travail, les candidats, ayant donné leur consentement par écrit et exclus ceux refusant d'adhérer à l'enquête. Les variables étudiées concernaient l’âge, le sexe, la population d’étude, l'activité professionnelle, l'acuité visuelle de loin et de près, la vision des couleurs, la catégorie du permis de conduire, et l'aptitude visuelle à la conduite automobile. La saisie et l'analyse des données ont été collectées au moyen d'une fiche d'enquête standardisée; après vérification et validation, elles ont été saisies sur le logiciel Excel Windows et analysées sur le logiciel Epi Info version 3.5.1. L’âge moyen des 406 candidats était de 29 ans ± 6,65 ans avec des extrêmes allant de 17 ans à 52 ans. Les hommes représentaient 283 (69,7%) et les femmes 123 (30,3%), soit un ratio de 2,3. Les fonctionnaires étaient retrouvés dans 39,4 % des cas, suivi des élèves-étudiants dans 33,5%. Dans notre population d’étude, 71 sur 406 candidats avaient une baisse de l'acuité visuelle de loin, soit 17,5%. Dans notre série, nous avons retrouvés 34 candidats âgés de 40 ans et plus, et seulement 14 candidats (41,2%) avaient une baisse de l'acuité visuelle de près. La quasi-totalité des patients avaient une vision de couleurs normale (99,5%), cependant 2 candidats avaient une vision de couleurs anormale, soit une prévalence de 0,5%. Dans notre échantillon, 403 (99,3%) sollicitaient un permis de conduire de catégorie léger (perms A, A1, B, F) et 3 (0,7%) sollicitaient un permis de conduire de type

  5. The effect on stability and thermal hydraulic quenchback of perforating the jacket of a cable-in-conduit conductor

    International Nuclear Information System (INIS)

    Dresner, L.

    1994-01-01

    This Paper continues earlier work on the reduction of the quench pressure in a doubler cable-in-conduit conductor achieved by perforating the inner jacket. The present study examines the effect of the perforations on the stability margin and on the ononset of thermal hydraulic quenchback

  6. Terrestrial analogs to lunar sinuous rilles - Kauhako Crater and channel, Kalaupapa, Molokai, and other Hawaiian lava conduit systems

    International Nuclear Information System (INIS)

    Coombs, C.R.; Hawke, B.R.; Wilson, L.

    1990-01-01

    Two source vents, one explosive and one effusive erupted to form a cinder cone and low lava shield that together compose the Kalaupapa peninsula of Molokai, Hawaii, A 50-100-m-wide channel/tube system extends 2.3 km northward from kauhako crater in the center of the shield. Based on modeling, a volume of up to about 0.2 cu km of lava erupted at a rate of 260 cu m/sec to flow through the Kauhako conduit system in one of the last eruptive episodes on the peninsula. Channel downcutting by thermal erosion occurred at a rate of about 10 micron/sec to help form the 30-m-deep conduit. Two smaller, secondary tube systems formed east of the main lava channel/tube. Several other lava conduit systems on the islands of Oahu and Hawaii were also compared to the Kauhako and lunar sinuous rille systems. These other lava conduits include Whittington, Kupaianaha, and Mauna Ulu lava tubes. Morphologically, the Hawaiian tube systems studied are very similar to lunar sinuous rilles in that they have deep head craters, sinuous channels, and gentle slopes. Thermal erosion is postulated to be an important factor in the formation of these terrestrial channel systems and by analogy is inferred to be an important process involved in the formation of lunar sinuous rilles. 28 refs

  7. Fast evolving conduits in clay-bonded sandstone: Characterization, erosion processes and significance for the origin of sandstone landforms

    Czech Academy of Sciences Publication Activity Database

    Bruthans, J.; Svetlik, D.; Soukup, J.; Schweigstillová, Jana; Válek, Jan; Sedláčková, M.; Mayo, A.L.

    2012-01-01

    Roč. 177, December (2012), s. 178-193 ISSN 0169-555X R&D Projects: GA AV ČR IAA300130806 Institutional support: RVO:67985891 ; RVO:68378297 Keywords : sandstone * erosion * piping * tensile strength * conduit * landform Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.552, year: 2012

  8. Inactive supply wells as conduits for flow and contaminant migration: conditions of occurrence and suggestions for management

    Science.gov (United States)

    Gailey, Robert M.

    2017-11-01

    Water supply wells can act as conduits for vertical flow and contaminant migration between water-bearing strata under common hydrogeologic and well construction conditions. While recognized by some for decades, there is little published data on the magnitude of flows and extent of resulting water quality impacts. Consequently, the issue may not be acknowledged widely enough and the need for better management persists. This is especially true for unconsolidated alluvial groundwater basins that are hydrologically stressed by agricultural activities. Theoretical and practical considerations indicate that significant water volumes can migrate vertically through wells. The flow is often downward, with shallow groundwater, usually poorer in quality, migrating through conduit wells to degrade deeper water quality. Field data from locations in California, USA, are presented in combination with modeling results to illustrate both the prevalence of conditions conducive to intraborehole flow and the resulting impacts to water quality. Suggestions for management of planned wells include better enforcement of current regulations and more detailed consideration of hydrogeologic conditions during design and installation. A potentially greater management challenge is presented by the large number of existing wells. Monitoring for evidence of conduit flow and solute transport in areas of high well density is recommended to identify wells that pose greater risks to water quality. Conduit wells that are discovered may be addressed through approaches that include structural modification and changes in operations.

  9. Dual-Component Gelatinous Peptide/Reactive Oligomer Formulations as Conduit Material and Luminal Filler for Peripheral Nerve Regeneration.

    Science.gov (United States)

    Kohn-Polster, Caroline; Bhatnagar, Divya; Woloszyn, Derek J; Richtmyer, Matthew; Starke, Annett; Springwald, Alexandra H; Franz, Sandra; Schulz-Siegmund, Michaela; Kaplan, Hilton M; Kohn, Joachim; Hacker, Michael C

    2017-05-21

    Toward the next generation of nerve guidance conduits (NGCs), novel biomaterials and functionalization concepts are required to address clinical demands in peripheral nerve regeneration (PNR). As a biological polymer with bioactive motifs, gelatinous peptides are promising building blocks. In combination with an anhydride-containing oligomer, a dual-component hydrogel system (cGEL) was established. First, hollow cGEL tubes were fabricated by a continuous dosing and templating process. Conduits were characterized concerning their mechanical strength, in vitro and in vivo degradation and biocompatibility. Second, cGEL was reformulated as injectable shear thinning filler for established NGCs, here tyrosine-derived polycarbonate-based braided conduits. Thereby, the formulation contained the small molecule LM11A-31. The biofunctionalized cGEL filler was assessed regarding building block integration, mechanical properties, in vitro cytotoxicity, and growth permissive effects on human adipose tissue-derived stem cells. A positive in vitro evaluation motivated further application of the filler material in a sciatic nerve defect. Compared to the empty conduit and pristine cGEL, the functionalization performed superior, though the autologous nerve graft remains the gold standard. In conclusion, LM11A-31 functionalized cGEL filler with extracellular matrix (ECM)-like characteristics and specific biochemical cues holds great potential to support PNR.

  10. A 40 kA NbTi cable in conduit conductor for the large poloidal field coils of net

    International Nuclear Information System (INIS)

    Torossian, A.; Bessette, D.; Turck, B.; Kazimierzak, B.

    1990-01-01

    The main feature of this cable in conduit design is to separate the manufacture of the full length of the steel conduit (400 m) and of the cable in order to minimize the industrial risk and consequently the cost. A circular cross section for that cable seems to be the most suitable for that purpose: - axisymmetric cabling with full transposition of strands, - cable behaviour independent of the field orientation, - less deformation of subcables, - cross section remains circular when the cable is under tension and makes the slippage of the cable in the conduit easier, - butt welding of 8 m long tubes forming the conduit becomes simpler. The square external shape allows to minimize the amount of insulating material and consequently improves the overall current density of the coil. This conductor is aimed to large poloidal field coils for NET which do not require high field and in that case NbTi seems to be the best choice with regard to reliability and cost but Nb 3 Sn could be used as well. Stainless steel ribbons are inserted between subcables in order to reduce losses induced by the rapid field changes and also to improve the mechanical behaviour of the cable

  11. FATIGUE PROPERTIES OF MODIFIED 316LN STAINLESS STEEL AT 4 K FOR HIGH FIELD CABLE-IN-CONDUIT APPLICATIONS

    International Nuclear Information System (INIS)

    Toplosky, V. J.; Walsh, R. P.; Han, K.

    2010-01-01

    Cable-In-Conduit-Conductor (CICC) alloys, exposed to Nb 3 Sn reaction heat-treatments, such as modified 316LN require a design specific database. A lack of fatigue life data (S-n curves) that could be applied in the design of the ITER CS and the NHMFL Series Connected Hybrid magnets is the impetus for the research presented here. The modified 316LN is distinguished by a lower carbon content and higher nitrogen content when compared to conventional 316LN. Because the interstitial alloying elements affect the mechanical properties significantly, it is necessary to characterize this alloy in a systematic way. In conjunction, to ensure magnet reliability and performance, several criteria and expectations must be met, including: high fatigue life at the operating stresses, optimal stress management at cryogenic temperatures and thin walled conduit to reduce coil mass. Tension-tension load control axial fatigue tests have good applicability to CICC solenoid magnet design, thus a series of 4 K strength versus fatigue life curves have been generated. In-situ samples of 316LN base metal, seam welded, butt welded and seam plus butt welded are removed directly from the conduit in order to address base and weld material fatigue life variability. The more than 30 fatigue tests show good grouping on the fatigue life curve and allow discretionary 4 K fatigue life predictions for conduit made with modified 316LN.

  12. Marine Toxins That Target Voltage-gated Sodium Channels

    Directory of Open Access Journals (Sweden)

    Robert J. French

    2006-04-01

    Full Text Available Abstract: Eukaryotic, voltage-gated sodium (NaV channels are large membrane proteins which underlie generation and propagation of rapid electrical signals in nerve, muscle and heart. Nine different NaV receptor sites, for natural ligands and/or drugs, have been identified, based on functional analyses and site-directed mutagenesis. In the marine ecosystem, numerous toxins have evolved to disrupt NaV channel function, either by inhibition of current flow through the channels, or by modifying the activation and inactivation gating processes by which the channels open and close. These toxins function in their native environment as offensive or defensive weapons in prey capture or deterrence of predators. In composition, they range from organic molecules of varying size and complexity to peptides consisting of ~10-70 amino acids. We review the variety of known NaV-targeted marine toxins, outlining, where known, their sites of interaction with the channel protein and their functional effects. In a number of cases, these natural ligands have the potential applications as drugs in clinical settings, or as models for drug development.

  13. SU-F-T-514: Evaluation of the Accuracy of Free-Breathing and Deep Inspiration Breath-Hold Gated Beam Delivery Using An Elekta Linac

    Energy Technology Data Exchange (ETDEWEB)

    Jermoumi, M; Cao, D; Housley, D; Shepard, D [Department of Radiation Oncology, Swedish Cancer Institute, Seattle, WA (United States); Xie, R [Ironwood Cancer and Research Centers, Chandler, AZ (United States)

    2016-06-15

    Purpose: In this study, we evaluated the performance of an Elekta linac in the delivery of gated radiotherapy. We examined whether the use of either a short gating window or a long beam hold impacts the accuracy of the delivery Methods: The performance of an Elekta linac in the delivery of gated radiotherapy was assessed using a 20cmX 20cm open field with the radiation delivered using a range of beam-on and beam-off time periods. Two SBRT plans were used to examine the accuracy of gated beam delivery for clinical treatment plans. For the SBRT cases, tests were performed for both free-breathing based gating and for gated delivery with a simulated breath-hold. A MatriXX 2D ion chamber array was used for data collection, and the gating accuracy was evaluated using gamma score. Results: For the 20cmX20cm open field, the gated beam delivery agreed closely with the non-gated delivery results. Discrepancies in the agreement, however, began to appear with a 5-to-1 ratio of the beam-off to beam-on. For these tight gating windows, each beam-on segment delivered a small number of monitor units. This finding was confirmed with dose distribution analysis from the delivery of the two VMAT plans where the gamma score(±1%,2%/1mm) showed passing rates in the range of 95% to 100% for gating windows of 25%, 38%, 50%, 63%, 75%, and 83%. Using a simulated sinusoidal breathing signal with a 4 second period, the gamma score of freebreathing gating and breath-hold gating deliveries were measured in the range of 95.7% to 100%. Conclusion: The results demonstrate that Elekta linacs can be used to accurately deliver respiratory gated treatments for both free-breathing and breath-hold patients. The accuracy of beams delivered in a gated delivery mode at low small MU proved higher than similar deliveries performed in a non-gated (manually interrupted) fashion.

  14. SU-F-T-514: Evaluation of the Accuracy of Free-Breathing and Deep Inspiration Breath-Hold Gated Beam Delivery Using An Elekta Linac

    International Nuclear Information System (INIS)

    Jermoumi, M; Cao, D; Housley, D; Shepard, D; Xie, R

    2016-01-01

    Purpose: In this study, we evaluated the performance of an Elekta linac in the delivery of gated radiotherapy. We examined whether the use of either a short gating window or a long beam hold impacts the accuracy of the delivery Methods: The performance of an Elekta linac in the delivery of gated radiotherapy was assessed using a 20cmX 20cm open field with the radiation delivered using a range of beam-on and beam-off time periods. Two SBRT plans were used to examine the accuracy of gated beam delivery for clinical treatment plans. For the SBRT cases, tests were performed for both free-breathing based gating and for gated delivery with a simulated breath-hold. A MatriXX 2D ion chamber array was used for data collection, and the gating accuracy was evaluated using gamma score. Results: For the 20cmX20cm open field, the gated beam delivery agreed closely with the non-gated delivery results. Discrepancies in the agreement, however, began to appear with a 5-to-1 ratio of the beam-off to beam-on. For these tight gating windows, each beam-on segment delivered a small number of monitor units. This finding was confirmed with dose distribution analysis from the delivery of the two VMAT plans where the gamma score(±1%,2%/1mm) showed passing rates in the range of 95% to 100% for gating windows of 25%, 38%, 50%, 63%, 75%, and 83%. Using a simulated sinusoidal breathing signal with a 4 second period, the gamma score of freebreathing gating and breath-hold gating deliveries were measured in the range of 95.7% to 100%. Conclusion: The results demonstrate that Elekta linacs can be used to accurately deliver respiratory gated treatments for both free-breathing and breath-hold patients. The accuracy of beams delivered in a gated delivery mode at low small MU proved higher than similar deliveries performed in a non-gated (manually interrupted) fashion.

  15. Intrinsic respiratory gating in small-animal CT

    International Nuclear Information System (INIS)

    Bartling, Soenke H.; Dinkel, Julien; Kauczor, Hans-Ulrich; Stiller, Wolfram; Semmler, Wolfhard; Grasruck, Michael; Madisch, Ijad; Gupta, Rajiv; Kiessling, Fabian

    2008-01-01

    Gating in small-animal CT imaging can compensate artefacts caused by physiological motion during scanning. However, all published gating approaches for small animals rely on additional hardware to derive the gating signals. In contrast, in this study a novel method of intrinsic respiratory gating of rodents was developed and tested for mice (n=5), rats (n=5) and rabbits (n=2) in a flat-panel cone-beam CT system. In a consensus read image quality was compared with that of non-gated and retrospective extrinsically gated scans performed using a pneumatic cushion. In comparison to non-gated images, image quality improved significantly using intrinsic and extrinsic gating. Delineation of diaphragm and lung structure improved in all animals. Image quality of intrinsically gated CT was judged to be equivalent to extrinsically gated ones. Additionally 4D datasets were calculated using both gating methods. Values for expiratory, inspiratory and tidal lung volumes determined with the two gating methods were comparable and correlated well with values known from the literature. We could show that intrinsic respiratory gating in rodents makes additional gating hardware and preparatory efforts superfluous. This method improves image quality and allows derivation of functional data. Therefore it bears the potential to find wide applications in small-animal CT imaging. (orig.)

  16. Close-out of open pit and waste rock piles of a uranium mine in Guangxi province of China

    International Nuclear Information System (INIS)

    Xu Lechang; Zhang Zhao; Zhang Guopu; Liu Min

    2012-01-01

    Close-out of projects of a mine in Guangxi province of China includes open pit,east and west waste rock piles, ore transfer station, industrial fields, buildings, ore transporting road, and equipment and conduits. The following remediation limits are introduced: environment penetrating radiation dose rate and 222 Rn flux of open pit and waste rock piles, 226 Ra specific activity of soil and individual dose. Remediation objective and programme are discussed in details. Remediation effects are evaluated. (authors)

  17. The pollution of the 'iron gate' reservoir

    International Nuclear Information System (INIS)

    Babic-Mladenovic, M.; Varga, S; Popovic, L.; Damjanovic, M.

    2002-01-01

    The paper presents the characteristics of the Iron Gate I (the Djerdap) Water Power and Navigational System, one of the largest in Europe (completed in 1972 by joint efforts of Yugoslavia and Romania). In this paper the attention is devoted to review of the sediment monitoring program and impacts of reservoir sedimentation, as well as to the investigations of water and sediment quality. Special consideration is paid to the issue of sediment pollution research needs. Namely, the hot spot of the 'Iron Gate' sedimentation represents a scarcely known pollution of sediment deposits. The present pollution probably is considerable, since the 'Iron Gate' reservoir drains about 577000 km 2 , with over 80 million inhabitants, and developed municipal and industrial infrastructure. Therefore, in the thirty-year reservoir life various types of sediment-bound pollutants entered and deposited within it. Especially severe incidents happened during 1999 (as a result of NATO bombing campaign) and 2000 (two accidental pollutions in the Tisza river catchment). The study of the 'Iron Gate' reservoir pollution should be prepared in order to enlighten the present state of reservoir sedimentation and pollution. The main objectives of the study are to enhance the government and public awareness of the present environmental state of the 'Iron Gate' reservoir and to serve as a baseline for all future actions. (author)

  18. Instantons in Self-Organizing Logic Gates

    Science.gov (United States)

    Bearden, Sean R. B.; Manukian, Haik; Traversa, Fabio L.; Di Ventra, Massimiliano

    2018-03-01

    Self-organizing logic is a recently suggested framework that allows the solution of Boolean truth tables "in reverse"; i.e., it is able to satisfy the logical proposition of gates regardless to which terminal(s) the truth value is assigned ("terminal-agnostic logic"). It can be realized if time nonlocality (memory) is present. A practical realization of self-organizing logic gates (SOLGs) can be done by combining circuit elements with and without memory. By employing one such realization, we show, numerically, that SOLGs exploit elementary instantons to reach equilibrium points. Instantons are classical trajectories of the nonlinear equations of motion describing SOLGs and connect topologically distinct critical points in the phase space. By linear analysis at those points, we show that these instantons connect the initial critical point of the dynamics, with at least one unstable direction, directly to the final fixed point. We also show that the memory content of these gates affects only the relaxation time to reach the logically consistent solution. Finally, we demonstrate, by solving the corresponding stochastic differential equations, that, since instantons connect critical points, noise and perturbations may change the instanton trajectory in the phase space but not the initial and final critical points. Therefore, even for extremely large noise levels, the gates self-organize to the correct solution. Our work provides a physical understanding of, and can serve as an inspiration for, models of bidirectional logic gates that are emerging as important tools in physics-inspired, unconventional computing.

  19. Capacitance-voltage characterization of fully silicided gated MOS capacitor

    International Nuclear Information System (INIS)

    Wang Baomin; Ru Guoping; Jiang Yulong; Qu Xinping; Li Bingzong; Liu Ran

    2009-01-01

    This paper investigates the capacitance-voltage (C-V) measurement on fully silicided (FUSI) gated metal-oxide-semiconductor (MOS) capacitors and the applicability of MOS capacitor models. When the oxide leakage current of an MOS capacitor is large, two-element parallel or series model cannot be used to obtain its real C-V characteristic. A three-element model simultaneously consisting of parallel conductance and series resistance or a four-element model with further consideration of a series inductance should be used. We employed the three-element and the four-element models with the help of two-frequency technique to measure the Ni FUSI gated MOS capacitors. The results indicate that the capacitance of the MOS capacitors extracted by the three-element model still shows some frequency dispersion, while that extracted by the four-element model is close to the real capacitance, showing little frequency dispersion. The obtained capacitance can be used to calculate the dielectric thickness with quantum effect correction by NCSU C-V program. We also investigated the influence of MOS capacitor's area on the measurement accuracy. The results indicate that the decrease of capacitor area can reduce the dissipation factor and improve the measurement accuracy. As a result, the frequency dispersion of the measured capacitance is significantly reduced, and real C-V characteristic can be obtained directly by the series model. In addition, this paper investigates the quasi-static C-V measurement and the photonic high-frequency C-V measurement on Ni FUSI metal gated MOS capacitor with a thin leaky oxide. The results indicate that the large tunneling current through the gate oxide significantly perturbs the accurate measurement of the displacement current, which is essential for the quasi-static C-V measurement. On the other hand, the photonic high-frequency C-V measurement can bypass the leakage problem, and get reliable low-frequency C-V characteristic, which can be used to

  20. Ventricular function during the acute rejection of heterotopic transplanted heart: Gated blood pool studies

    International Nuclear Information System (INIS)

    Valette, H.; Bourguignon, M.H.; Desruennes, M.; Merlet, P.; Le Guludec, D.; Syrota, A.

    1991-01-01

    Twenty patients who had undergone a heterotopic heart transplant were studied prospectively to determine the relationship between rejection and ventricular dysfunction assessed from gated blood pool studies. A fully automated method for detecting ventricular edges was implemented; its success rate for the grafted left and right ventricles was 94% and 77%, respectively. The parameters, peak ejection and filling rates, were calculated pixel per pixel using a two-harmonic Fourier algorithm and then averaged over the ventricular region of interest. Peak filling and ejection rates were closely related with the severity of the rejection, while the left ventricular ejection fraction was not. Peak filling rates of both ventricles were the indices closely related to the presence of moderate rejection. Despite the low number of patients, these data suggested that gated blood pool derived indices of ventricular function are associated with ventricular dysfunction resulting from myocarditis rejection. Radionuclide ventriculography provides parametric data which are accurate and reliable for the diagnosis of rejection. (orig.)

  1. Thermally induced pressure locking of gate valves: A survey of valve bonnet pressurization rates

    International Nuclear Information System (INIS)

    Ezekoye, L.I.; Moore, W.E.

    1996-01-01

    Closed, water filled gate valves run the risk of becoming pressurized due to heat input from the environment or from adjacent connected piping. Thermal pressurization of gate valve bonnets may lead to the valves failing to open on demand and can even induce structural failure of valves. This paper presents an analytical prediction of the pressurization rate of a closed pressure vessel subject to uniform heating which may be considered as an upper bound to the pressurization rate that may occur in the field. Then actual valve experiences described in the literature are reviewed to determine the expected pressurization rate in existing hardware designs. A statistical approach is applied to reconcile the differing pressurization rates reported in the literature and determine a rate that can be applied in valve evaluations. The limitations of the reconciled rate are discussed

  2. The impact of gated Communities on property values: evidence of changes in real estate markets -Los Angeles, 1980-2000

    Directory of Open Access Journals (Sweden)

    Renaud Le Goix

    2007-05-01

    Full Text Available The paper focuses on how gated communities, as private means of providing public infrastructure and security, real estate products and club-economies, produce changes in housing market patterns. Based on an empirical study of Los Angeles (California data, it aims to trace to what extent gates and walls favor property values and if the presence of gated communities produces over time (1980-2000 a deterrent effect on non-gated properties abutting the enclave, or close to it. Resulting from a demand for security, gated communities are a leading offer from the homebuilding industry. But their spread emerges from a partnership between local governments and land developers. Both agree to charge the homebuyer with the cost of urban sprawl (construction and maintenance costs of infrastructure within the gates. Such a structuring of residential space is particularly desirable on the urban edges, where the cost of urban sprawl exceeds the financial assets of local public authorities. New private developments provide local governments with new wealthy taxpayers at almost no cost. As compensation, the homebuyer is granted private and exclusive access to sites and amenities (lakes, beaches, etc.. Such exclusivity favors the location rent, and usually positively affects the property values within the gated enclaves. But it is also assumed that operating cost of private governance are paid for by the increase of property values. Market failure nevertheless occurs when costs rise above sustainable levels compared to property values. Changes produced by gates yield to at least two outcomes. At first sight, residential enclosures produce a price premium, thus being a smart investment. Furthermore, gated communities might well be able to generate enough property value to pay off the price of private governance. But this analysis holds only on a short term basis. In the long term, larger and wealthier gated communities are successful in shielding their property

  3. Restaurants closed over Christmas

    CERN Multimedia

    2011-01-01

    The restaurants will be closed during the Christmas holiday period : please note that all three CERN Restaurants will be closed from 5 p.m. on Wednesday, 21 December until Wednesday, 4 January inclusive. The Restaurants will reopen on Thursday, 5 January 2012.

  4. Early results of gate valve flow interruption blowdown tests

    International Nuclear Information System (INIS)

    DeWall, K.G.

    1988-01-01

    The preliminary results of the USNRC/INEL high-energy BWR line break flow interruption testing are presented. Two representative nuclear valve assemblies were cycled under design basis Reactor Water Cleanup pipe break conditions to provide input for the technical basis for resolving the Nuclear Regulatory Commission's Generic Issue 87. The effects of the blowdown hydraulic loadings on valve operability, especially valve closure stem forces, were studied. The blowdown tests showed that, given enough thrust, typical gate valves will close against the high flow resulting from a line break. The tests also showed that proper operator sizing depends on the correct identification of values for the sizing equation. Evidence exists that values used in the past may not be conservative for all valve applications. The tests showed that improper operator lock ring installation following test or maintenance can invalidate in-situ test results and prevent the valve from performing its design function. 2 refs., 12 figs., 2 tabs

  5. Voltage-sensing domain mode shift is coupled to the activation gate by the N-terminal tail of hERG channels.

    Science.gov (United States)

    Tan, Peter S; Perry, Matthew D; Ng, Chai Ann; Vandenberg, Jamie I; Hill, Adam P

    2012-09-01

    Human ether-a-go-go-related gene (hERG) potassium channels exhibit unique gating kinetics characterized by unusually slow activation and deactivation. The N terminus of the channel, which contains an amphipathic helix and an unstructured tail, has been shown to be involved in regulation of this slow deactivation. However, the mechanism of how this occurs and the connection between voltage-sensing domain (VSD) return and closing of the gate are unclear. To examine this relationship, we have used voltage-clamp fluorometry to simultaneously measure VSD motion and gate closure in N-terminally truncated constructs. We report that mode shifting of the hERG VSD results in a corresponding shift in the voltage-dependent equilibrium of channel closing and that at negative potentials, coupling of the mode-shifted VSD to the gate defines the rate of channel closure. Deletion of the first 25 aa from the N terminus of hERG does not alter mode shifting of the VSD but uncouples the shift from closure of the cytoplasmic gate. Based on these observations, we propose the N-terminal tail as an adaptor that couples voltage sensor return to gate closure to define slow deactivation gating in hERG channels. Furthermore, because the mode shift occurs on a time scale relevant to the cardiac action potential, we suggest a physiological role for this phenomenon in maximizing current flow through hERG channels during repolarization.

  6. Active gated imaging for automotive safety applications

    Science.gov (United States)

    Grauer, Yoav; Sonn, Ezri

    2015-03-01

    The paper presents the Active Gated Imaging System (AGIS), in relation to the automotive field. AGIS is based on a fast gated-camera equipped with a unique Gated-CMOS sensor, and a pulsed Illuminator, synchronized in the time domain to record images of a certain range of interest which are then processed by computer vision real-time algorithms. In recent years we have learned the system parameters which are most beneficial to night-time driving in terms of; field of view, illumination profile, resolution and processing power. AGIS provides also day-time imaging with additional capabilities, which enhances computer vision safety applications. AGIS provides an excellent candidate for camera-based Advanced Driver Assistance Systems (ADAS) and the path for autonomous driving, in the future, based on its outstanding low/high light-level, harsh weather conditions capabilities and 3D potential growth capabilities.

  7. Four-gate transistor analog multiplier circuit

    Science.gov (United States)

    Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)

    2011-01-01

    A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.

  8. VHDL-based programming environment for Floating-Gate analog memory cell

    Directory of Open Access Journals (Sweden)

    Carlos Alberto dos Reis Filho

    2005-02-01

    Full Text Available An implementation in CMOS technology of a Floating-Gate Analog Memory Cell and Programming Environment is presented. A digital closed-loop control compares a reference value set by user and the memory output and after cycling, the memory output is updated and the new value stored. The circuit can be used as analog trimming for VLSI applications where mechanical trimming associated with postprocessing chip is prohibitive due to high costs.

  9. A Survey on Modeling and Simulation of MEMS Switches and Its Application in Power Gating Techniques

    OpenAIRE

    Pramod Kumar M.P; A.S. Augustine Fletcher

    2014-01-01

    Large numbers of techniques have been developed to reduce the leakage power, including supply voltage scaling, varying threshold voltages, smaller logic banks, etc. Power gating is a technique which is used to reduce the static power when the sleep transistor is in off condition. Micro Electro mechanical System (MEMS) switches have properties that are very close to an ideal switch, with infinite off-resistance due to an air gap and low on-resistance due to the ohmic metal to m...

  10. Liquid-based gating mechanism with tunable multiphase selectivity and antifouling behaviour.

    Science.gov (United States)

    Hou, Xu; Hu, Yuhang; Grinthal, Alison; Khan, Mughees; Aizenberg, Joanna

    2015-03-05

    Living organisms make extensive use of micro- and nanometre-sized pores as gatekeepers for controlling the movement of fluids, vapours and solids between complex environments. The ability of such pores to coordinate multiphase transport, in a highly selective and subtly triggered fashion and without clogging, has inspired interest in synthetic gated pores for applications ranging from fluid processing to 3D printing and lab-on-chip systems. But although specific gating and transport behaviours have been realized by precisely tailoring pore surface chemistries and pore geometries, a single system capable of controlling complex, selective multiphase transport has remained a distant prospect, and fouling is nearly inevitable. Here we introduce a gating mechanism that uses a capillary-stabilized liquid as a reversible, reconfigurable gate that fills and seals pores in the closed state, and creates a non-fouling, liquid-lined pore in the open state. Theoretical modelling and experiments demonstrate that for each transport substance, the gating threshold-the pressure needed to open the pores-can be rationally tuned over a wide pressure range. This enables us to realize in one system differential response profiles for a variety of liquids and gases, even letting liquids flow through the pore while preventing gas from escaping. These capabilities allow us to dynamically modulate gas-liquid sorting in a microfluidic flow and to separate a three-phase air-water-oil mixture, with the liquid lining ensuring sustained antifouling behaviour. Because the liquid gating strategy enables efficient long-term operation and can be applied to a variety of pore structures and membrane materials, and to micro- as well as macroscale fluid systems, we expect it to prove useful in a wide range of applications.

  11. Liquid-based gating mechanism with tunable multiphase selectivity and antifouling behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Hou, X; Hu, YH; Grinthal, A; Khan, M; Aizenberg, J

    2015-03-04

    Living organisms make extensive use of micro- and nanometre-sized pores as gatekeepers for controlling the movement of fluids, vapours and solids between complex environments. The ability of such pores to coordinate multiphase transport, in a highly selective and subtly triggered fashion and without clogging, has inspired interest in synthetic gated pores for applications ranging from fluid processing to 3D printing and lab-on-chip systems(1-10). But although specific gating and transport behaviours have been realized by precisely tailoring pore surface chemistries and pore geometries(6,11-17), a single system capable of controlling complex, selective multiphase transport has remained a distant prospect, and fouling is nearly inevitable(11,12). Here we introduce a gating mechanism that uses a capillary-stabilized liquid as a reversible, reconfigurable gate that fills and seals pores in the closed state, and creates a non-fouling, liquid-lined pore in the open state. Theoretical modelling and experiments demonstrate that for each transport substance, the gating threshold-the pressure needed to open the pores-can be rationally tuned over a wide pressure range. This enables us to realize in one system differential response profiles for a variety of liquids and gases, even letting liquids flow through the pore while preventing gas from escaping. These capabilities allow us to dynamically modulate gas-liquid sorting in a microfluidic flow and to separate a three-phase air-water-oil mixture, with the liquid lining ensuring sustained antifouling behaviour. Because the liquid gating strategy enables efficient long-term operation and can be applied to a variety of pore structures and membrane materials, and to micro- as well as macroscale fluid systems, we expect it to prove useful in a wide range of applications.

  12. ISAC's Gating-ML 2.0 data exchange standard for gating description.

    Science.gov (United States)

    Spidlen, Josef; Moore, Wayne; Brinkman, Ryan R

    2015-07-01

    The lack of software interoperability with respect to gating has traditionally been a bottleneck preventing the use of multiple analytical tools and reproducibility of flow cytometry data analysis by independent parties. To address this issue, ISAC developed Gating-ML, a computer file format to encode and interchange gates. Gating-ML 1.5 was adopted and published as an ISAC Candidate Recommendation in 2008. Feedback during the probationary period from implementors, including major commercial software companies, instrument vendors, and the wider community, has led to a streamlined Gating-ML 2.0. Gating-ML has been significantly simplified and therefore easier to support by software tools. To aid developers, free, open source reference implementations, compliance tests, and detailed examples are provided to stimulate further commercial adoption. ISAC has approved Gating-ML as a standard ready for deployment in the public domain and encourages its support within the community as it is at a mature stage of development having undergone extensive review and testing, under both theoretical and practical conditions. © 2015 International Society for Advancement of Cytometry.

  13. Quality verification for respiratory gated proton therapy

    International Nuclear Information System (INIS)

    Kim, Eun Sook; Jang, Yo Jong; Park, Ji Yeon; Kang, Dong Yun; Yeom, Doo Seok

    2013-01-01

    To verify accuracy of respiratory gated proton therapy by measuring and analyzing proton beam delivered when respiratory gated proton therapy is being performed in our institute. The plan data of 3 patients who took respiratory gated proton therapy were used to deliver proton beam from proton therapy system. The manufactured moving phantom was used to apply respiratory gating system to reproduce proton beam which was partially irradiated. The key characteristics of proton beam, range, spreat-out Bragg peak (SOBP) and output factor were measured 5 times and the same categories were measured in the continuous proton beam which was not performed with respiratory gating system. Multi-layer ionization chamber was used to measure range and SOBP, and Scanditronix Wellhofer and farmer chamber was used to measure output factor. The average ranges of 3 patients (A, B, C), who had taken respiratory gated proton therapy or not, were (A) 7.226, 7.230, (B) 12.216, 12.220 and (C) 19.918, 19.920 g/cm 2 and average SOBP were (A) 4.950, 4.940, (B) 6.496, 6.512 and (C) 8.486, 8.490 g/cm 2 . And average output factor were (A) 0.985, 0.984 (B) 1.026, 1.027 and (C) 1.138, 1.136 cGy/MU. The differences of average range were -0.004, -0.004, -0.002 g/cm 2 , that of SOBP were 0.010, -0.016, -0.004 g/cm 2 and that of output factor were 0.001, -0.001, 0.002 cGy/MU. It is observed that the range, SOBP and output factor of proton beam delivered when respiratory gated proton therapy is being performed have the same beam quality with no significant difference compared to the proton beam which was continuously irradiated. Therefore, this study verified the quality of proton beam delivered when respiratory gated proton therapy and confirmed the accuracy of proton therapy using this

  14. Round Gating for Low Energy Block Ciphers

    DEFF Research Database (Denmark)

    Banik, Subhadeep; Bogdanov, Andrey; Regazzoni, Francesco

    2016-01-01

    design techniques for implementing block ciphers in a low energy fashion. We concentrate on round based implementation and we discuss how gating, applied at round level can affect and improve the energy consumption of the most common lightweight block cipher currently used in the internet of things....... Additionally, we discuss how to needed gating wave can be generated. Experimental results show that our technique is able to reduce the energy consumption in most block ciphers by over 60% while incurring only a minimal overhead in hardware....

  15. Closed string field theory

    International Nuclear Information System (INIS)

    Strominger, A.

    1987-01-01

    A gauge invariant cubic action describing bosonic closed string field theory is constructed. The gauge symmetries include local spacetime diffeomorphisms. The conventional closed string spectrum and trilinear couplings are reproduced after spontaneous symmetry breaking. The action S is constructed from the usual ''open string'' field of ghost number minus one half. It is given by the associator of the string field product which is non-vanishing because of associativity anomalies. S does not describe open string propagation because open string states associate and can thereby be shifted away. A field theory of closed and open strings can be obtained by adding to S the cubic open string action. (orig.)

  16. Pipe closing device

    International Nuclear Information System (INIS)

    Klahn, F.C.; Nolan, J.H.; Wills, C.

    1979-01-01

    The closing device closes the upper end of a support tube for monitoring samples. It meshes with the upper connecting piece of the monitorung sample capsule, and loads the capsule within the bore of the support tube, so that it is fixed but can be released. The closing device consists of an interlocking component with a chamber and several ratchets which hang down. The interlocking component surrounds the actuating component for positioning the ratchets. The interlocking and actuating components are movable axially relative to each other. (DG) [de

  17. Long-Term Regeneration and Functional Recovery of a 15 mm Critical Nerve Gap Bridged by Tremella fuciformis Polysaccharide-Immobilized Polylactide Conduits

    Directory of Open Access Journals (Sweden)

    Shan-hui Hsu

    2013-01-01

    Full Text Available Novel peripheral nerve conduits containing the negatively charged Tremella fuciformis polysaccharide (TF were prepared, and their efficacy in bridging a critical nerve gap was evaluated. The conduits were made of poly(D,L-lactide (PLA with asymmetric microporous structure. TF was immobilized on the lumen surface of the nerve conduits after open air plasma activation. The TF-modified surface was characterized by the attenuated total reflection Fourier-transformed infrared spectroscopy and the scanning electron microscopy. TF modification was found to enhance the neurotrophic gene expression of C6 glioma cells in vitro. TF-modified PLA nerve conduits were tested for their ability to bridge a 15 mm gap of rat sciatic nerve. Nerve regeneration was monitored by the magnetic resonance imaging. Results showed that TF immobilization promoted the nerve connection in 6 weeks. The functional recovery in animals receiving TF-immobilized conduits was greater than in those receiving the bare conduits during an 8-month period. The degree of functional recovery reached ~90% after 8 months in the group of TF-immobilized conduits.

  18. Fabrication of bioactive conduits containing the fibroblast growth factor 1 and neural stem cells for peripheral nerve regeneration across a 15 mm critical gap

    International Nuclear Information System (INIS)

    Ni, Hsiao-Chiang; Tseng, Ting-Chen; Hsu, Shan-hui; Chen, Jeng-Rung; Chiu, Ing-Ming

    2013-01-01

    Nerve conduits are often used in combination with bioactive molecules and stem cells to enhance peripheral nerve regeneration. In this study, the acidic fibroblast growth factor 1 (FGF1) was immobilized onto the microporous/micropatterned poly (D, L-lactic acid) (PLA) nerve conduits after open air plasma treatment. PLA substrates grafted with chitosan in the presence of a small amount of gold nanoparticles (nano Au) showed a protective effect on the activity of the immobilized FGF1 in vitro. Different conduits were tested for their ability to bridge a 15 mm critical gap defect in a rat sciatic nerve injury model. Axon regeneration and functional recovery were evaluated by histology, walking track analysis and electrophysiology. Among different conduits, PLA conduits grafted with chitosan–nano Au and the FGF1 after plasma activation had the greatest regeneration capacity and functional recovery in the experimental animals. When the above conduit was seeded with aligned neural stem cells, the efficacy was further enhanced and it approached that of the autograft group. This work suggested that microporous/micropatterned nerve conduits containing bioactive growth factors may be successfully fabricated by micropatterning techniques, open plasma activation, and immobilization, which, combined with aligned stem cells, may synergistically contribute to the regeneration of the severely damaged peripheral nerve. (paper)

  19. Determination of prospective displacement-based gate threshold for respiratory-gated radiation delivery from retrospective phase-based gate threshold selected at 4D CT simulation

    International Nuclear Information System (INIS)

    Vedam, S.; Archambault, L.; Starkschall, G.; Mohan, R.; Beddar, S.

    2007-01-01

    Four-dimensional (4D) computed tomography (CT) imaging has found increasing importance in the localization of tumor and surrounding normal structures throughout the respiratory cycle. Based on such tumor motion information, it is possible to identify the appropriate phase interval for respiratory gated treatment planning and delivery. Such a gating phase interval is determined retrospectively based on tumor motion from internal tumor displacement. However, respiratory-gated treatment is delivered prospectively based on motion determined predominantly from an external monitor. Therefore, the simulation gate threshold determined from the retrospective phase interval selected for gating at 4D CT simulation may not correspond to the delivery gate threshold that is determined from the prospective external monitor displacement at treatment delivery. The purpose of the present work is to establish a relationship between the thresholds for respiratory gating determined at CT simulation and treatment delivery, respectively. One hundred fifty external respiratory motion traces, from 90 patients, with and without audio-visual biofeedback, are analyzed. Two respiratory phase intervals, 40%-60% and 30%-70%, are chosen for respiratory gating from the 4D CT-derived tumor motion trajectory. From residual tumor displacements within each such gating phase interval, a simulation gate threshold is defined based on (a) the average and (b) the maximum respiratory displacement within the phase interval. The duty cycle for prospective gated delivery is estimated from the proportion of external monitor displacement data points within both the selected phase interval and the simulation gate threshold. The delivery gate threshold is then determined iteratively to match the above determined duty cycle. The magnitude of the difference between such gate thresholds determined at simulation and treatment delivery is quantified in each case. Phantom motion tests yielded coincidence of simulation

  20. Defense.gov Special Report: Travels with Gates - October 2010

    Science.gov (United States)

    - Secretary of State Hillary Rodham Clinton and Defense Secretary Robert M. Gates expressed support for the Travels Top Story Clinton, Gates Voice Support For Afghan Reconciliation BRUSSELS, Belgium, Oct. 14, 2010

  1. Gate errors in solid-state quantum-computer architectures

    International Nuclear Information System (INIS)

    Hu Xuedong; Das Sarma, S.

    2002-01-01

    We theoretically consider possible errors in solid-state quantum computation due to the interplay of the complex solid-state environment and gate imperfections. In particular, we study two examples of gate operations in the opposite ends of the gate speed spectrum, an adiabatic gate operation in electron-spin-based quantum dot quantum computation and a sudden gate operation in Cooper-pair-box superconducting quantum computation. We evaluate quantitatively the nonadiabatic operation of a two-qubit gate in a two-electron double quantum dot. We also analyze the nonsudden pulse gate in a Cooper-pair-box-based quantum-computer model. In both cases our numerical results show strong influences of the higher excited states of the system on the gate operation, clearly demonstrating the importance of a detailed understanding of the relevant Hilbert-space structure on the quantum-computer operations

  2. Experimental composite guidance conduits for peripheral nerve repair: An evaluation of ion release

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X.F. [Department of Biological Sciences and Medical Engineering Design and Innovation Centre, Cork Institute of Technology, Cork (Ireland); Coughlan, A. [Inamori School of Engineering, Alfred University, Alfred, NY. 14802 (United States); O' Shea, H. [Department of Biological Sciences and Medical Engineering Design and Innovation Centre, Cork Institute of Technology, Cork (Ireland); Towler, M.R. [Inamori School of Engineering, Alfred University, Alfred, NY. 14802 (United States); Kehoe, S., E-mail: sharonkehoe@dal.ca [Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, B3H 4R2 (Canada); School of Biomedical Engineering, Dalhousie University, Halifax, NS, B3H 4R2 (Canada); Boyd, D., E-mail: d.boyd@dal.ca [Department of Applied Oral Sciences, Dalhousie University, Halifax, NS, B3H 4R2 (Canada); School of Biomedical Engineering, Dalhousie University, Halifax, NS, B3H 4R2 (Canada)

    2012-08-01

    Poly (lactide-co-glycolide) (PLGA) - Pluronic F127 - glass composites have demonstrated excellent potential, from the perspective of controlled mechanical properties and cytocompatibility, for peripheral nerve regeneration. In addition to controlling the mechanical properties and cytotoxicity for such composite devices, the glass component may mediate specific responses upon implantation via degradation in the physiological environment and release of constituent elements. However, research focused on quantifying the release levels of such therapeutic ions from these experimental medical devices has been limited. To redress the balance, this paper explores the ion release profiles for Si{sup 4+}, Ca{sup 2+}, Na{sup +}, Zn{sup 2+}, and Ce{sup 4+} from experimental composite nerve guidance conduits (CNGC) comprising PLGA (at 12.5, and 20 wt.%), F127 (at 0, 2.5 and 5 wt.%) and various loadings of Si-Ca-Na-Zn-Ce glass (at 20 and 40 wt.%) for incubation periods of up to 28 days. The concentration of each ion, at various time points, was determined using Inductively Coupled Plasma-Atomic Emission Spectrometry (Perkin Elmer Optima 3000). It was observed that the Si{sup 4+}, Na{sup +}, Ca{sup 2+}, Zn{sup 2+} release from CNGCs in this study ranged from 0.22 to 6.477 ppm, 2.307 to 3.277 ppm, 40 to 119 ppm, and 45 to 51 ppm, respectively. The Ce{sup 4+} concentrations were under the minimum detection limits for the ICP instrument utilized. The results indicate that the ion release levels may be appropriate to mediate therapeutic effects with respect to peripheral nerve regeneration. The data generated in this paper provides requisite evidence to optimize composition for pre-clinical evaluation of the experimental composite. - Graphical abstract: Highlights: Black-Right-Pointing-Pointer Time-dependent degradation studies of PLGA/glass composite nerve guidance conduits (NGCs). Black-Right-Pointing-Pointer Si{sup 4+}, Na{sup +}, Ca{sup 2+} and Zn{sup 2+} release levels for the

  3. Tunable pulse-shaping with gated graphene nanoribbons

    DEFF Research Database (Denmark)

    Prokopeva, Ludmila; Emani, Naresh K.; Boltasseva, Alexandra

    2014-01-01

    We propose a pulse-shaper made of gated graphene nanoribbons. Simulations demonstrate tunable control over the shapes of transmitted and reflected pulses using the gating bias. Initial fabrication and characterization of graphene elements is also discussed.......We propose a pulse-shaper made of gated graphene nanoribbons. Simulations demonstrate tunable control over the shapes of transmitted and reflected pulses using the gating bias. Initial fabrication and characterization of graphene elements is also discussed....

  4. Self-gated fat-suppressed cardiac cine MRI.

    Science.gov (United States)

    Ingle, R Reeve; Santos, Juan M; Overall, William R; McConnell, Michael V; Hu, Bob S; Nishimura, Dwight G

    2015-05-01

    To develop a self-gated alternating repetition time balanced steady-state free precession (ATR-SSFP) pulse sequence for fat-suppressed cardiac cine imaging. Cardiac gating is computed retrospectively using acquired magnetic resonance self-gating data, enabling cine imaging without the need for electrocardiogram (ECG) gating. Modification of the slice-select rephasing gradients of an ATR-SSFP sequence enables the acquisition of a one-dimensional self-gating readout during the unused short repetition time (TR). Self-gating readouts are acquired during every TR of segmented, breath-held cardiac scans. A template-matching algorithm is designed to compute cardiac trigger points from the self-gating signals, and these trigger points are used for retrospective cine reconstruction. The proposed approach is compared with ECG-gated ATR-SSFP and balanced steady-state free precession in 10 volunteers and five patients. The difference of ECG and self-gating trigger times has a variability of 13 ± 11 ms (mean ± SD). Qualitative reviewer scoring and ranking indicate no statistically significant differences (P > 0.05) between self-gated and ECG-gated ATR-SSFP images. Quantitative blood-myocardial border sharpness is not significantly different among self-gated ATR-SSFP ( 0.61±0.15 mm -1), ECG-gated ATR-SSFP ( 0.61±0.15 mm -1), or conventional ECG-gated balanced steady-state free precession cine MRI ( 0.59±0.15 mm -1). The proposed self-gated ATR-SSFP sequence enables fat-suppressed cardiac cine imaging at 1.5 T without the need for ECG gating and without decreasing the imaging efficiency of ATR-SSFP. © 2014 Wiley Periodicals, Inc.

  5. r-Universal reversible logic gates

    International Nuclear Information System (INIS)

    Vos, A de; Storme, L

    2004-01-01

    Reversible logic plays a fundamental role both in ultra-low power electronics and in quantum computing. It is therefore important to know which reversible logic gates can be used as building block for the reversible implementation of an arbitrary boolean function and which cannot

  6. Gate protective device for SOS array

    Science.gov (United States)

    Meyer, J. E., Jr.; Scott, J. H.

    1972-01-01

    Protective gate device consisting of alternating heavily doped n(+) and p(+) diffusions eliminates breakdown voltages in silicon oxide on sapphire arrays caused by electrostatic discharge from person or equipment. Diffusions are easily produced during normal double epitaxial processing. Devices with nine layers had 27-volt breakdown.

  7. Phase analysis in gated blood pool tomography

    International Nuclear Information System (INIS)

    Nakajima, Kenichi; Bunko, Hisashi; Tada, Akira; Taki, Junichi; Nanbu, Ichiro

    1984-01-01

    Phase analysis of gated blood pool study has been applied to detect the site of accessory conduction pathway (ACP) in the Wolff-Parkinson-White (WPW) syndrome; however, there was a limitation to detect the precise location of ACP by phase analysis alone. In this study, we applied phase analysis to gated blood pool tomography using seven pin hole tomography (7PT) and gated emission computed tomography (GECT) in 21 patients with WPW syndrome and 3 normal subjects. In 17 patients, the sites of ACPs were confirmed by epicardial mapping and the result of the surgical division of ACP. In 7PT, the site of ACP grossly agreed to the abnormal initial phase in phase image in 5 out of 6 patients with left cardiac type. In GECT, phase images were generated in short axial, vertical and horizontal long axial sections. In 8 out of 9 patients, the site of ACP was correctly identified by phase images, and in a patient who had two ACPs, initial phase corresponded to one of the two locations. Phase analysis of gated blood pool tomography has advantages for avoiding overlap of blood pools and for estimating three-dimensional propagation of the contraction, and can be a good adjunctive method in patients with WPW syndrome. (author)

  8. Comparison of gate capacitance extraction methodologies

    NARCIS (Netherlands)

    Kazmi, S.N.R.; Schmitz, Jurriaan

    2008-01-01

    In recent years, many new capacitance-voltage measurement approaches have been presented in literature. New approaches became necessary with the rapidly increasing gate current density in newer CMOS generations. Here we present a simulation platform using Silvaco software, to describe the full chain

  9. Disrupted sensory gating in pathological gambling.

    Science.gov (United States)

    Stojanov, Wendy; Karayanidis, Frini; Johnston, Patrick; Bailey, Andrew; Carr, Vaughan; Schall, Ulrich

    2003-08-15

    Some neurochemical evidence as well as recent studies on molecular genetics suggest that pathologic gambling may be related to dysregulated dopamine neurotransmission. The current study examined sensory (motor) gating in pathologic gamblers as a putative measure of endogenous brain dopamine activity with prepulse inhibition of the acoustic startle eye-blink response and the auditory P300 event-related potential. Seventeen pathologic gamblers and 21 age- and gender-matched healthy control subjects were assessed. Both prepulse inhibition measures were recorded under passive listening and two-tone prepulse discrimination conditions. Compared to the control group, pathologic gamblers exhibited disrupted sensory (motor) gating on all measures of prepulse inhibition. Sensory motor gating deficits of eye-blink responses were most profound at 120-millisecond prepulse lead intervals in the passive listening task and at 240-millisecond prepulse lead intervals in the two-tone prepulse discrimination task. Sensory gating of P300 was also impaired in pathologic gamblers, particularly at 500-millisecond lead intervals, when performing the discrimination task on the prepulse. In the context of preclinical studies on the disruptive effects of dopamine agonists on prepulse inhibition, our findings suggest increased endogenous brain dopamine activity in pathologic gambling in line with previous neurobiological findings.

  10. Corner Office Interview: Gates Foundation's Deborah Jacobs

    Science.gov (United States)

    Miller, Rebecca

    2010-01-01

    U.S. libraries gave the world a top talent when Deborah Jacobs left her transformational role as City Librarian of Seattle in 2008 to head the Bill & Melinda Gates Foundation's Global Libraries program, the international sibling to the U.S. Libraries program. The initiative fosters national-scale projects with grantees in transitioning countries…

  11. Quantum gates via relativistic remote control

    Energy Technology Data Exchange (ETDEWEB)

    Martín-Martínez, Eduardo, E-mail: emartinm@uwaterloo.ca [Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Dept. Applied Math., University of Waterloo, Ontario, N2L 3G1 (Canada); Perimeter Institute for Theoretical Physics, Waterloo, Ontario N2L 2Y5 (Canada); Sutherland, Chris [Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)

    2014-12-12

    We harness relativistic effects to gain quantum control on a stationary qubit in an optical cavity by controlling the non-inertial motion of a different probe atom. Furthermore, we show that by considering relativistic trajectories of the probe, we enhance the efficiency of the quantum control. We explore the possible use of these relativistic techniques to build 1-qubit quantum gates.

  12. State memory in solution gated epitaxial graphene

    Science.gov (United States)

    Butko, A. V.; Butko, V. Y.; Lebedev, S. P.; Lebedev, A. A.; Davydov, V. Y.; Smirnov, A. N.; Eliseyev, I. A.; Dunaevskiy, M. S.; Kumzerov, Y. A.

    2018-06-01

    We studied electrical transport in transistors fabricated on a surface of high quality epitaxial graphene with density of defects as low as 5·1010 cm-2 and observed quasistatic hysteresis with a time constant in a scale of hours. This constant is in a few orders of magnitude greater than the constant previously reported in CVD graphene. The hysteresis observed here can be described as a shift of ∼+2V of the Dirac point measured during a gate voltage increase from the position of the Dirac point measured during a gate voltage decrease. This hysteresis can be characterized as a nonvolatile quasistatic state memory effect in which the state of the gated graphene is determined by its initial state prior to entering the hysteretic region. Due to this effect the difference in resistance of the gated graphene measured in the hysteretic region at the same applied voltages can be as high as 70%. The observed effect can be explained by assuming that charge carriers in graphene and oppositely charged molecular ions from the solution form quasistable interfacial complexes at the graphene interface. These complexes likely preserve the initial state by preventing charge carriers in graphene from discharging in the hysteretic region.

  13. An electronically controlled automatic security access gate

    Directory of Open Access Journals (Sweden)

    Jonathan A. ENOKELA

    2014-11-01

    Full Text Available The security challenges being encountered in many places require electronic means of controlling access to communities, recreational centres, offices, and homes. The electronically controlled automated security access gate being proposed in this work helps to prevent an unwanted access to controlled environments. This is achieved mainly through the use of a Radio Frequency (RF transmitter-receiver pair. In the design a microcontroller is programmed to decode a given sequence of keys that is entered on a keypad and commands a transmitter module to send out this code as signal at a given radio frequency. Upon reception of this RF signal by the receiver module, another microcontroller activates a driver circuitry to operate the gate automatically. The codes for the microcontrollers were written in C language and were debugged and compiled using the KEIL Micro vision 4 integrated development environment. The resultant Hex files were programmed into the memories of the microcontrollers with the aid of a universal programmer. Software simulation was carried out using the Proteus Virtual System Modeling (VSM version 7.7. A scaled-down prototype of the system was built and tested. The electronically controlled automated security access gate can be useful in providing security for homes, organizations, and automobile terminals. The four-character password required to operate the gate gives the system an increased level of security. Due to its standalone nature of operation the system is cheaper to maintain in comparison with a manually operated type.

  14. High-fidelity gates in quantum dot spin qubits.

    Science.gov (United States)

    Koh, Teck Seng; Coppersmith, S N; Friesen, Mark

    2013-12-03

    Several logical qubits and quantum gates have been proposed for semiconductor quantum dots controlled by voltages applied to top gates. The different schemes can be difficult to compare meaningfully. Here we develop a theoretical framework to evaluate disparate qubit-gating schemes on an equal footing. We apply the procedure to two types of double-dot qubits: the singlet-triplet and the semiconducting quantum dot hybrid qubit. We investigate three quantum gates that flip the qubit state: a DC pulsed gate, an AC gate based on logical qubit resonance, and a gate-like process known as stimulated Raman adiabatic passage. These gates are all mediated by an exchange interaction that is controlled experimentally using the interdot tunnel coupling g and the detuning [Symbol: see text], which sets the energy difference between the dots. Our procedure has two steps. First, we optimize the gate fidelity (f) for fixed g as a function of the other control parameters; this yields an f(opt)(g) that is universal for different types of gates. Next, we identify physical constraints on the control parameters; this yields an upper bound f(max) that is specific to the qubit-gate combination. We show that similar gate fidelities (~99:5%) should be attainable for singlet-triplet qubits in isotopically purified Si, and for hybrid qubits in natural Si. Considerably lower fidelities are obtained for GaAs devices, due to the fluctuating magnetic fields ΔB produced by nuclear spins.

  15. Gate Engineering in SOI LDMOS for Device Reliability

    Directory of Open Access Journals (Sweden)

    Aanand

    2016-01-01

    Full Text Available A linearly graded doping drift region with step gate structure, used for improvement of reduced surface field (RESURF SOI LDMOS transistor performance has been simulated with 0.35µm technology in this paper. The proposed device has one poly gate and double metal gate arranged in a stepped manner, from channel to drift region. The first gate uses n+ poly (near source where as other two gates of aluminium. The first gate with thin gate oxide has good control over the channel charge. The third gate with thick gate oxide at drift region reduce gate to drain capacitance. The arrangement of second and third gates in a stepped manner in drift region spreads the electric field uniformly. Using two dimensional device simulations, the proposed SOI LDMOS is compared with conventional structure and the extended metal structure. We demonstrate that the proposed device exhibits significant enhancement in linearity, breakdown voltage, on-resistance and HCI. Double metal gate reduces the impact ionization area which helps to improve the Hot Carrier Injection effect..

  16. Normal p50 gating in unmedicated schizophrenia outpatients

    DEFF Research Database (Denmark)

    Arnfred, Sidse M; Chen, Andrew C.N.; Glenthøj, Birte Y

    2003-01-01

    The hypothesis of a sensory gating defect in schizophrenia has been supported by studies demonstrating deficient auditory P50 gating in patients. P50 gating is the relative attenuation of P50 amplitude in the auditory evoked potential following the second auditory stimulus of a stimulus pair....

  17. Optical Co-Incidence Gate | Srinivasulu | African Journal of Science ...

    African Journals Online (AJOL)

    The paper explains Optical co-incidence gate, realized using Unijunction transistors (UJT), Light emitting diodes (LED) and Photo-resistors (LDR), which works on 1.8Vdc instead of 3Vdc. The power dissipation of the designed gate is only 3 mW. This optical gate finds application in the field of Mechatronics, Instrumentation ...

  18. High frequency MOSFET gate drivers technologies and applications

    CERN Document Server

    Zhang, Zhiliang

    2017-01-01

    This book describes high frequency power MOSFET gate driver technologies, including gate drivers for GaN HEMTs, which have great potential in the next generation of switching power converters. Gate drivers serve as a critical role between control and power devices.

  19. Online junction temperature measurement using peak gate current

    DEFF Research Database (Denmark)

    Baker, Nick; Munk-Nielsen, Stig; Iannuzzo, Francesco

    2015-01-01

    A new method for junction temperature measurement of MOS-gated power semiconductor switches is presented. The measurement method involves detecting the peak voltage over the external gate resistor of an IGBT or MOSFET during turn-on. This voltage is directly proportional to the peak gate current...

  20. Low band-to-band tunnelling and gate tunnelling current in novel nanoscale double-gate architecture: simulations and investigation

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Deepanjan [Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47906 (United States); Ganguly, Samiran [Department of Electronics Engineering, Indian School of Mines, Dhanbad-826004 (India); Dasgupta, S [Department of Electronics and Computer Engineering, Indian Institute of Technology, Roorkee-247667 (India)

    2007-05-30

    Large band-to-band tunnelling (BTBT) and gate leakage current can limit scalability of nanoscale devices. In this paper, we have proposed a novel nanoscale parallel connected heteromaterial double gate (PCHEM-DG) architecture with triple metal gate which significantly suppress BTBT leakage, making it efficient for low power design in the sub-10 nm regime. We have also proposed a triple gate device with p{sup +} poly-n{sup +} poly-p{sup +} poly gate which has substantially low gate leakage over symmetric DG MOSFET. Simulations are performed using a 2D Poisson-Schroedinger simulator and verified with a 2D device simulator ATLAS. We conclude that, due to intrinsic body doping, negligible gate leakage, suppressed BTBT over symmetric DG devices, metal gate (MG) PCHEM-DG MOSFET is efficient for low power circuit design in the nanometre regime.

  1. Low band-to-band tunnelling and gate tunnelling current in novel nanoscale double-gate architecture: simulations and investigation

    International Nuclear Information System (INIS)

    Datta, Deepanjan; Ganguly, Samiran; Dasgupta, S

    2007-01-01

    Large band-to-band tunnelling (BTBT) and gate leakage current can limit scalability of nanoscale devices. In this paper, we have proposed a novel nanoscale parallel connected heteromaterial double gate (PCHEM-DG) architecture with triple metal gate which significantly suppress BTBT leakage, making it efficient for low power design in the sub-10 nm regime. We have also proposed a triple gate device with p + poly-n + poly-p + poly gate which has substantially low gate leakage over symmetric DG MOSFET. Simulations are performed using a 2D Poisson-Schroedinger simulator and verified with a 2D device simulator ATLAS. We conclude that, due to intrinsic body doping, negligible gate leakage, suppressed BTBT over symmetric DG devices, metal gate (MG) PCHEM-DG MOSFET is efficient for low power circuit design in the nanometre regime

  2. Reconfigurable logic via gate controlled domain wall trajectory in magnetic network structure

    Science.gov (United States)

    Murapaka, C.; Sethi, P.; Goolaup, S.; Lew, W. S.

    2016-01-01

    An all-magnetic logic scheme has the advantages of being non-volatile and energy efficient over the conventional transistor based logic devices. In this work, we present a reconfigurable magnetic logic device which is capable of performing all basic logic operations in a single device. The device exploits the deterministic trajectory of domain wall (DW) in ferromagnetic asymmetric branch structure for obtaining different output combinations. The programmability of the device is achieved by using a current-controlled magnetic gate, which generates a local Oersted field. The field generated at the magnetic gate influences the trajectory of the DW within the structure by exploiting its inherent transverse charge distribution. DW transformation from vortex to transverse configuration close to the output branch plays a pivotal role in governing the DW chirality and hence the output. By simply switching the current direction through the magnetic gate, two universal logic gate functionalities can be obtained in this device. Using magnetic force microscopy imaging and magnetoresistance measurements, all basic logic functionalities are demonstrated. PMID:26839036

  3. Biomolecule-recognition gating membrane using biomolecular cross-linking and polymer phase transition.

    Science.gov (United States)

    Kuroki, Hidenori; Ito, Taichi; Ohashi, Hidenori; Tamaki, Takanori; Yamaguchi, Takeo

    2011-12-15

    We present for the first time a biomolecule-recognition gating system that responds to small signals of biomolecules by the cooperation of biorecognition cross-linking and polymer phase transition in nanosized pores. The biomolecule-recognition gating membrane immobilizes the stimuli-responsive polymer, including the biomolecule-recognition receptor, onto the pore surface of a porous membrane. The pore state (open/closed) of this gating membrane depends on the formation of specific biorecognition cross-linking in the pores: a specific biomolecule having multibinding sites can be recognized by several receptors and acts as the cross-linker of the grafted polymer, whereas a nonspecific molecule cannot. The pore state can be distinguished by a volume phase transition of the grafted polymer. In the present study, the principle of the proposed system is demonstrated using poly(N-isopropylacrylamide) as the stimuli-responsive polymer and avidin-biotin as a multibindable biomolecule-specific receptor. As a result of the selective response to the specific biomolecule, a clear permeability change of an order of magnitude was achieved. The principle is versatile and can be applied to many combinations of multibindable analyte-specific receptors, including antibody-antigen and lectin-sugar analogues. The new gating system can find wide application in the bioanalytical field and aid the design of novel biodevices.

  4. COHERENTLY DEDISPERSED GATED IMAGING OF MILLISECOND PULSARS

    International Nuclear Information System (INIS)

    Roy, Jayanta; Bhattacharyya, Bhaswati

    2013-01-01

    Motivated by the need for rapid localization of newly discovered faint millisecond pulsars (MSPs), we have developed a coherently dedispersed gating correlator. This gating correlator accounts for the orbital motions of MSPs in binaries while folding the visibilities with a best-fit topocentric rotational model derived from a periodicity search in a simultaneously generated beamformer output. Unique applications of the gating correlator for sensitive interferometric studies of MSPs are illustrated using the Giant Metrewave Radio Telescope (GMRT) interferometric array. We could unambiguously localize five newly discovered Fermi MSPs in the on-off gated image plane with an accuracy of ±1''. Immediate knowledge of such a precise position enables the use of sensitive coherent beams of array telescopes for follow-up timing observations which substantially reduces the use of telescope time (∼20× for the GMRT). In addition, a precise a priori astrometric position reduces the effect of large covariances in the timing fit (with discovery position, pulsar period derivative, and an unknown binary model), which in-turn accelerates the convergence to the initial timing model. For example, while fitting with the precise a priori position (±1''), the timing model converges in about 100 days, accounting for the effect of covariance between the position and pulsar period derivative. Moreover, such accurate positions allow for rapid identification of pulsar counterparts at other wave bands. We also report a new methodology of in-beam phase calibration using the on-off gated image of the target pulsar, which provides optimal sensitivity of the coherent array removing possible temporal and spacial decoherences.

  5. COHERENTLY DEDISPERSED GATED IMAGING OF MILLISECOND PULSARS

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Jayanta; Bhattacharyya, Bhaswati [National Centre for Radio Astrophysics, Pune 411007 (India)

    2013-03-10

    Motivated by the need for rapid localization of newly discovered faint millisecond pulsars (MSPs), we have developed a coherently dedispersed gating correlator. This gating correlator accounts for the orbital motions of MSPs in binaries while folding the visibilities with a best-fit topocentric rotational model derived from a periodicity search in a simultaneously generated beamformer output. Unique applications of the gating correlator for sensitive interferometric studies of MSPs are illustrated using the Giant Metrewave Radio Telescope (GMRT) interferometric array. We could unambiguously localize five newly discovered Fermi MSPs in the on-off gated image plane with an accuracy of {+-}1''. Immediate knowledge of such a precise position enables the use of sensitive coherent beams of array telescopes for follow-up timing observations which substantially reduces the use of telescope time ({approx}20 Multiplication-Sign for the GMRT). In addition, a precise a priori astrometric position reduces the effect of large covariances in the timing fit (with discovery position, pulsar period derivative, and an unknown binary model), which in-turn accelerates the convergence to the initial timing model. For example, while fitting with the precise a priori position ({+-}1''), the timing model converges in about 100 days, accounting for the effect of covariance between the position and pulsar period derivative. Moreover, such accurate positions allow for rapid identification of pulsar counterparts at other wave bands. We also report a new methodology of in-beam phase calibration using the on-off gated image of the target pulsar, which provides optimal sensitivity of the coherent array removing possible temporal and spacial decoherences.

  6. Dosimetry applications in GATE Monte Carlo toolkit.

    Science.gov (United States)

    Papadimitroulas, Panagiotis

    2017-09-01

    Monte Carlo (MC) simulations are a well-established method for studying physical processes in medical physics. The purpose of this review is to present GATE dosimetry applications on diagnostic and therapeutic simulated protocols. There is a significant need for accurate quantification of the absorbed dose in several specific applications such as preclinical and pediatric studies. GATE is an open-source MC toolkit for simulating imaging, radiotherapy (RT) and dosimetry applications in a user-friendly environment, which is well validated and widely accepted by the scientific community. In RT applications, during treatment planning, it is essential to accurately assess the deposited energy and the absorbed dose per tissue/organ of interest, as well as the local statistical uncertainty. Several types of realistic dosimetric applications are described including: molecular imaging, radio-immunotherapy, radiotherapy and brachytherapy. GATE has been efficiently used in several applications, such as Dose Point Kernels, S-values, Brachytherapy parameters, and has been compared against various MC codes which are considered as standard tools for decades. Furthermore, the presented studies show reliable modeling of particle beams when comparing experimental with simulated data. Examples of different dosimetric protocols are reported for individualized dosimetry and simulations combining imaging and therapy dose monitoring, with the use of modern computational phantoms. Personalization of medical protocols can be achieved by combining GATE MC simulations with anthropomorphic computational models and clinical anatomical data. This is a review study, covering several dosimetric applications of GATE, and the different tools used for modeling realistic clinical acquisitions with accurate dose assessment. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  7. The dynamics of slug trains in volcanic conduits: Evidence for expansion driven slug coalescence

    Science.gov (United States)

    Pering, T. D.; McGonigle, A. J. S.; James, M. R.; Capponi, A.; Lane, S. J.; Tamburello, G.; Aiuppa, A.

    2017-12-01

    Strombolian volcanism is a ubiquitous form of activity, driven by the ascent and bursting of bubbles of slug morphology. Whilst considerable attention has been devoted to understanding the behaviour of individual slugs in this regime, relatively little is known about how inter-slug interactions modify flow conditions. Recently, we reported on high temporal frequency strombolian activity on Etna, in which the larger erupted slug masses were followed by longer intervals before the following explosion than the smaller bursts (Pering et al., 2015). We hypothesised that this behaviour arose from the coalescence of ascending slugs causing a prolonged lag before arrival of the next distinct bubble. Here we consider the potential importance of inter-slug interactions for the dynamics of strombolian volcanism, by reporting on the first study into the behaviour of trains of ascending gas slugs, scaled to the expansion rates in volcanic conduits. This laboratory analogue study illustrates that slugs in trains rise faster than individual slugs, and can be associated with aspects of co-current flow. The work also highlights that coalescence and inter-slug interactions play an important role in modulating slug train behaviour. We also report, for the first time, on slug coalescence driven by vertical expansion of the trailing slug, a process which can occur, even where the leading slug base ascent velocity is greater than that of the trailing slug.

  8. Effect of Surface Pore Structure of Nerve Guide Conduit on Peripheral Nerve Regeneration

    Science.gov (United States)

    Oh, Se Heang; Kim, Jin Rae; Kwon, Gu Birm; Namgung, Uk; Song, Kyu Sang

    2013-01-01

    Polycaprolactone (PCL)/Pluronic F127 nerve guide conduits (NGCs) with different surface pore structures (nano-porous inner surface vs. micro-porous inner surface) but similar physical and chemical properties were fabricated by rolling the opposite side of asymmetrically porous PCL/F127 membranes. The effect of the pore structure on peripheral nerve regeneration through the NGCs was investigated using a sciatic nerve defect model of rats. The nerve fibers and tissues were shown to have regenerated along the longitudinal direction through the NGC with a nano-porous inner surface (Nanopore NGC), while they grew toward the porous wall of the NGC with a micro-porous inner surface (Micropore NGC) and, thus, their growth was restricted when compared with the Nanopore NGC, as investigated by immunohistochemical evaluations (by fluorescence microscopy with anti-neurofilament staining and Hoechst staining for growth pattern of nerve fibers), histological evaluations (by light microscopy with Meyer's modified trichrome staining and Toluidine blue staining and transmission electron microscopy for the regeneration of axon and myelin sheath), and FluoroGold retrograde tracing (for reconnection between proximal and distal stumps). The effect of nerve growth factor (NGF) immobilized on the pore surfaces of the NGCs on nerve regeneration was not so significant when compared with NGCs not containing immobilized NGF. The NGC system with different surface pore structures but the same chemical/physical properties seems to be a good tool that is used for elucidating the surface pore effect of NGCs on nerve regeneration. PMID:22871377

  9. Thermo-Hydraulic behaviour of dual-channel superconducting Cable-In-Conduit Conductors for ITER

    International Nuclear Information System (INIS)

    Renard, B.

    2006-09-01

    In an effort to optimise the cryogenics of large superconducting coils for fusion applications (ITER), dual channel Cable-In-Conduit Conductors (CICC) are designed with a central channel spiral to provide low hydraulic resistance and faster helium circulation. The qualitative and economic rationale of the conductor central channel is here justified to limit the superconductor temperature increase, but brings more complexity to the conductor cooling characteristics. The pressure drop of spirals is experimentally evaluated in nitrogen and water and an explicit hydraulic friction model is proposed. Temperatures in the cable must be quantified to guarantee superconductor margin during coil operation under heat disturbance and set adequate inlet temperature. Analytical one-dimensional thermal models, in steady state and in transient, allow to better understand the thermal coupling of CICC central and annular channels. The measurement of a heat transfer characteristic space and time constants provides cross-checking experimental estimations of the internal thermal homogenization. A simple explicit model of global inter-channel heat exchange coefficient is proposed. The risk of thermosyphon between the two channels is considered since vertical portions of fusion coils are subject to gravity. The new hydraulic model, heat exchange model and gravitational risk ratio allow the thermohydraulic improvement of CICC central spirals. (author)

  10. The Medial Temporal Lobe – Conduit of Parallel Connectivity: A model for Attention, Memory, and Perception.

    Directory of Open Access Journals (Sweden)

    Brian B. Mozaffari

    2014-11-01

    Full Text Available Based on the notion that the brain is equipped with a hierarchical organization, which embodies environmental contingencies across many time scales, this paper suggests that the medial temporal lobe (MTL – located deep in the hierarchy – serves as a bridge connecting supra to infra – MTL levels. Bridging the upper and lower regions of the hierarchy provides a parallel architecture that optimizes information flow between upper and lower regions to aid attention, encoding, and processing of quick complex visual phenomenon. Bypassing intermediate hierarchy levels, information conveyed through the MTL ‘bridge’ allows upper levels to make educated predictions about the prevailing context and accordingly select lower representations to increase the efficiency of predictive coding throughout the hierarchy. This selection or activation/deactivation is associated with endogenous attention. In the event that these ‘bridge’ predictions are inaccurate, this architecture enables the rapid encoding of novel contingencies. A review of hierarchical models in relation to memory is provided along with a new theory, Medial-temporal-lobe Conduit for Parallel Connectivity (MCPC. In this scheme, consolidation is considered as a secondary process, occurring after a MTL-bridged connection, which eventually allows upper and lower levels to access each other directly. With repeated reactivations, as contingencies become consolidated, less MTL activity is predicted. Finally, MTL bridging may aid processing transient but structured perceptual events, by allowing communication between upper and lower levels without calling on intermediate levels of representation.

  11. Enhanced peripheral nerve regeneration through asymmetrically porous nerve guide conduit with nerve growth factor gradient.

    Science.gov (United States)

    Oh, Se Heang; Kang, Jun Goo; Kim, Tae Ho; Namgung, Uk; Song, Kyu Sang; Jeon, Byeong Hwa; Lee, Jin Ho

    2018-01-01

    In this study, we fabricated a nerve guide conduit (NGC) with nerve growth factor (NGF) gradient along the longitudinal direction by rolling a porous polycaprolactone membrane with NGF concentration gradient. The NGF immobilized on the membrane was continuously released for up to 35 days, and the released amount of the NGF from the membrane gradually increased from the proximal to distal NGF ends, which may allow a neurotrophic factor gradient in the tubular NGC for a sufficient period. From the in vitro cell culture experiment, it was observed that the PC12 cells sense the NGF concentration gradient on the membrane for the cell proliferation and differentiation. From the in vivo animal experiment using a long gap (20 mm) sciatic nerve defect model of rats, the NGC with NGF concentration gradient allowed more rapid nerve regeneration through the NGC than the NGC itself and NGC immobilized with uniformly distributed NGF. The NGC with NGF concentration gradient seems to be a promising strategy for the peripheral nerve regeneration. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 52-64, 2018. © 2017 Wiley Periodicals, Inc.

  12. A new cable-in-conduit conductor magnet with insulated strands

    International Nuclear Information System (INIS)

    Yamaguchi, Satarou; Yamamoto, Junya; Motojima, Osamu.

    1995-09-01

    Many studies have used cable-in-conduit conductor (CICC) coils in trying to develop an AC superconducting magnet because of its enormous potential if AC losses were low and insulation voltage was high. The strands in the most recent CICC magnets are coated with chromium or another metal with high electrical resistance to order to induce current re-distribution among the strands and to avoid a quench caused by a current imbalance. Current re-distribution is highly complex and very difficult to analyze because the conditions of the strand surfaces and the contact areas vary greatly with the operation of the conductor. If, however, the cable currents were well-balanced, insulating the strands would be the best way to reduce AC losses. We propose a new CICC magnet structure featuring a current lead that balances the strand currents via its resistance. Having calculated current balances, we find that strand currents are well within the present parameters for nuclear fusion experiments and superconducting magnet energy storages. (author)

  13. A Decaheme Cytochrome as a Molecular Electron Conduit in Dye-Sensitized Photoanodes

    Science.gov (United States)

    Hwang, Ee Taek; Sheikh, Khizar; Orchard, Katherine L; Hojo, Daisuke; Radu, Valentin; Lee, Chong-Yong; Ainsworth, Emma; Lockwood, Colin; Gross, Manuela A; Adschiri, Tadafumi; Reisner, Erwin; Butt, Julea N; Jeuken, Lars J C

    2015-01-01

    In nature, charge recombination in light-harvesting reaction centers is minimized by efficient charge separation. Here, it is aimed to mimic this by coupling dye-sensitized TiO2 nanocrystals to a decaheme protein, MtrC from Shewanella oneidensis MR-1, where the 10 hemes of MtrC form a ≈7-nm-long molecular wire between the TiO2 and the underlying electrode. The system is assembled by forming a densely packed MtrC film on an ultra-flat gold electrode, followed by the adsorption of approximately 7 nm TiO2 nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP). The step-by-step construction of the MtrC/TiO2 system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM). Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the MtrC conduit. In other words, in these TiO2/MtrC hybrid photodiodes, MtrC traps the conduction-band electrons from TiO2 before transferring them to the electrode, creating a photobioelectrochemical system in which a redox protein is used to mimic the efficient charge separation found in biological photosystems. PMID:26180522

  14. Normal zone propagation and Thermal Hydraulic Quenchback in a cable-in-conduit superconductor

    International Nuclear Information System (INIS)

    Lue, J.W.; Dresner, L.

    1993-01-01

    When a local normal zone appears in a cable-in-conduit superconductor, a slug of hot helium is produced. The pressure rises and the hot helium expands. Thus the normal zone propagation in such a conductor can be governed by the hot helium expansion, rather than the heat conduction along the conductor. The expansion of the hot helium compresses the cold helium outside of the normal zone. This raises th at sign temperature of the cold helium. When the temperature rise reaches the current sharing limit, the superconductor in contact goes normal. Thus a rapid increase in normal zone propagation occur. This phenomenon is termed Thermal Hydraulic Quenchback (THQ). An experiment was performed to investigate this process. The existence of THQ was verified. Thresholds of THQ were also observed by varying the conductor current, the magnetic field, the temperature, and the initial normal zone length. When THQ occurred, normal zone propagation approaching the velocity of sound was observed. A better picture of THQ is obtained by a careful comparison of the data with analytical studies

  15. Solid-cryogen-stabilized, cable-in-conduit (CIC) superconducting cables

    Science.gov (United States)

    Voccio, J. P.; Michael, P. C.; Bromberg, L.; Hahn, S.

    2015-12-01

    This paper considers the use of a solid cryogen as a means to stabilize, both mechanically and thermally, magnesium diboride (MgB2) superconducting strands within a dual-channel cable-in-conduit (CIC) cable for use in AC applications, such as a generator stator winding. The cable consists of two separate channels; the outer channel contains the superconducting strands and is filled with a fluid (liquid or gas) that becomes solid at the device operating temperature. Several options for fluid will be presented, such as liquid nitrogen, hydrocarbons and other chlorofluorocarbons (CFCs) that have a range of melting temperatures and volumetric expansions (from solid at operating temperature to fixed volume at room temperature). Implications for quench protection and conductor stability, enhanced through direct contact with the solid cryogen, which has high heat capacity and thermal conductivity (compared with helium gas), will be presented. Depending on the cryogen, the conductor will be filled initially either with liquid at atmospheric conditions or a gas at high pressure (∼100 atm). After cooldown, the cryogen in the stranded-channel will be solid, essentially locking the strands in place, preventing strand motion and degradation due to mechanical deformation while providing enhanced thermal capacity for stability and protection. The effect of cryogen porosity is also considered. The relatively high heat capacity of solid cryogens at these lower temperatures (compared to gaseous helium) enhances the thermal stability of the winding. During operation, coolant flow through the open inner channel will minimize pressure drop.

  16. Literature Review: Double-Barrelled Wet Colostomy (One Stoma) versus Ileal Conduit with Colostomy (Two Stomas).

    Science.gov (United States)

    Gan, Jason; Hamid, Rizwan

    2017-01-01

    The aim of this literature review was to analyse the advantages and disadvantages of a traditional ileal conduit (IC) with separate colostomy technique compared to the outcomes of a double-barrelled wet colostomy (DBWC) technique. The former technique results in the formation of two stomas, and the latter results in the formation of one stoma. PubMed was searched electronically for articles on DBWC. Fifteen articles were retrieved and of them 13 were included in the literature review (350 patients). Of the articles, 3 directly compared DBWC to IC with colostomy. Review of 13 DBWC articles demonstrated perioperative mortality ranging between 0 and 11.1% and postoperative complications ranging from 0 to 100%. Three of the studies directly compared DBWC to IC with colostomy; median operating times and length of stay were shorter in DBWC patients (p colostomy technique, as it requires only one stoma. This literature review supports the use of the technically less challenging DBWC technique as a viable alternative to the traditional IC with colostomy technique. © 2016 S. Karger AG, Basel.

  17. The effects of fenoldopam on coronary conduit blood flow after coronary artery bypass graft surgery.

    LENUS (Irish Health Repository)

    Halpenny, M

    2012-02-03

    OBJECTIVE: To quantify the effects of fenoldopam, 0.1 microg\\/kg\\/min, on left internal mammary artery (LIMA) and saphenous vein blood flow after coronary anastomosis. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: University teaching hospital, single institution. PARTICIPANTS: Thirty-one American Society of Anesthesiologists III patients undergoing elective coronary revascularization. INTERVENTIONS: A perivascular ultrasonic flow probe (Linton Instrumentation, Norfolk, UK) was placed around the LIMA and saphenous vein graft after coronary anastomosis. MEASUREMENTS AND MAIN RESULTS: Immediately before and at 5-minute intervals for 15 minutes after starting the infusion, blood flow was measured in the LIMA and one saphenous vein graft using a transit time ultrasonic flow probe. Heart rate, blood pressure, and central venous pressure were documented at these time points. Administration of fenoldopam, 0.1 microg\\/kg\\/min, did not alter heart rate or blood pressure. A small, nonsignificant increase in LIMA blood flow occurred during the 15-minute study period (30 +\\/- 12 to 35 +\\/- 10 mL\\/min) in patients who received fenoldopam. No significant changes occurred in the placebo group. CONCLUSIONS: The findings indicate that fenoldopam, 0.1 microg\\/kg\\/min, did not influence coronary conduit blood flow to a clinically significant extent. The small increase in LIMA blood flow may be of greater importance in high-risk patients or in the prevention of coronary arterial spasm.

  18. Exploring the role of lipids in intercellular conduits: breakthroughs in the pipeline

    Directory of Open Access Journals (Sweden)

    Elise eDelage

    2013-12-01

    Full Text Available It has been known for more than a century that most of the plant cells are connected to their neighbors through membranous pores perforating the cell wall, namely plasmodesmata (PDs. The recent discovery of tunneling nanotubes (TNTs, thin membrane bridges established between distant mammalian cells, suggests that intercellular communication mediated through cytoplasmic continuity could be a conserved feature of eukaryotic organisms. Although TNTs differ from PDs in their formation and architecture, both are characterized by a continuity of the plasma membrane between two cells, delimiting a nanotubular channel supported by actin-based cytoskeleton. Due to this unusual membrane organization, lipids are likely to play critical roles in the formation and stability of intercellular conduits like TNTs and PDs, but also in regulating the transfer through these structures. While it is crucial for a better understanding of those fascinating communication highways, the study of TNT lipid composition and dynamics turned out to be extremely challenging. The present review aims to give an overview of the recent findings in this context. We will also discuss some of the promising imaging approaches, which might be the key for future breakthroughs in the field and could also benefit the research on PDs.

  19. Contention between supply of hydrothermal fluid and conduit obstruction: inferences from numerical simulations

    Science.gov (United States)

    Tanaka, Ryo; Hashimoto, Takeshi; Matsushima, Nobuo; Ishido, Tsuneo

    2018-05-01

    We investigate a volcanic hydrothermal system using numerical simulations, focusing on change in crater temperature. Both increases and decreases in crater temperature have been observed before phreatic eruptions. We follow the system's response for up to a decade after hydrothermal fluid flux from the deep part of the system is increased and permeability is reduced at a certain depth in a conduit. Our numerical simulations demonstrate that: (1) changes in crater temperature are controlled by the magnitude of the increase in hydrothermal fluid flux and the degree of permeability reduction; (2) significant increases in hydrothermal flux with decreases in permeability induce substantial pressure changes in shallow depths in the edifice and decreases in crater temperature; (3) the location of maximum pressure change differs between the mechanisms. The results of this study imply that it is difficult to predict eruptions by crater temperature change alone. One should be as wary of large eruptions when crater temperature decreases as when crater temperature increases. It is possible to clarify the implications of changes in crater temperature with simultaneous observation of ground deformation.

  20. Glacier surge mechanism based on linked cavity configuration of the basal water conduit system

    Science.gov (United States)

    Kamb, Barclay

    1987-08-01

    Based on observations of the 1982-1983 surge of Variegated Glacier, Alaska, a model of the surge mechanism is developed in terms of a transition from the normal tunnel configuration of the basal water conduit system to a linked cavity configuration that tends to restrict the flow of water, resulting in increased basal water pressures that cause rapid basal sliding. The linked cavity system consists of basal cavities formed by ice-bedrock separation (cavitation), ˜1 m high and ˜10 m in horizontal dimensions, widely scattered over the glacier bed, and hydraulically linked by narrow connections where separation is minimal (separation gap ≲ 0.1 m). The narrow connections, called orifices, control the water flow through the conduit system; by throttling the flow through the large cavities, the orifices keep the water flux transmitted by the basal water system at normal levels even though the total cavity cross-sectional area (˜200 m2) is much larger than that of a tunnel system (˜10 m2). A physical model of the linked cavity system is formulated in terms of the dimensions of the "typical" cavity and orifice and the numbers of these across the glacier width. The model concentrates on the detailed configuration of the typical orifice and its response to basal water pressure and basal sliding, which determines the water flux carried by the system under given conditions. Configurations are worked out for two idealized orifice types, step orifices that form in the lee of downglacier-facing bedrock steps, and wave orifices that form on the lee slopes of quasisinusoidal bedrock waves and are similar to transverse "N channels." The orifice configurations are obtained from the results of solutions of the basal-sliding-with-separation problem for an ice mass constituting of linear half-space of linear rheology, with nonlinearity introduced by making the viscosity stress-dependent on an intuitive basis. Modification of the orifice shapes by melting of the ice roof due to

  1. The side-to-side fashion for individual distal coronary anastomosis using venous conduit.

    Science.gov (United States)

    Kato, Takayoshi; Tsunekawa, Tomohiro; Motoji, Yusuke; Hirakawa, Akihiro; Okawa, Yasuhide; Tomita, Shinji

    2017-04-01

    Regarding to coronary artery bypass grafting (CABG), the end-to-side anastomosis (ESA) has been performed as a gold standard. Recently, the effectiveness of the distal side-to-side anastomosis (SSA) in CABG using internal mammary artery has been reported. The benefit of SSA comparing to ESA also has been disclosed by computing simulation. However, use of SSA by venous conduit for individual CABG has not been reported. In this study, we investigated feasibility of SSA. From January 2013 to October 2014, we conducted 114 CABGs. There were 92 venous distal anastomoses without sequential anastomotic site (61 SSA and 31 ESA). The anastomosis was evaluated before discharge and at 1 year after the procedure by angiography or multi-detector row computed tomographic coronary angiography. The median values for time to anastomosis were 13 min in the two group (p = 0.89). There was no revision of anastomosis in both groups. Additional stitches for hemostasis were required significantly less in SSA than ESA (18.0 vs 45.2 %, respectively, p fashion is easy to perform and maybe beneficial in blood flow pattern.

  2. Low-power DRAM-compatible Replacement Gate High-k/Metal Gate Stacks

    Science.gov (United States)

    Ritzenthaler, R.; Schram, T.; Bury, E.; Spessot, A.; Caillat, C.; Srividya, V.; Sebaai, F.; Mitard, J.; Ragnarsson, L.-Å.; Groeseneken, G.; Horiguchi, N.; Fazan, P.; Thean, A.

    2013-06-01

    In this work, the possibility of integration of High-k/Metal Gate (HKMG), Replacement Metal Gate (RMG) gate stacks for low power DRAM compatible transistors is studied. First, it is shown that RMG gate stacks used for Logic applications need to be seriously reconsidered, because of the additional anneal(s) needed in a DRAM process. New solutions are therefore developed. A PMOS stack HfO2/TiN with TiN deposited in three times combined with Work Function metal oxidations is demonstrated, featuring a very good Work Function of 4.95 eV. On the other hand, the NMOS side is shown to be a thornier problem to solve: a new solution based on the use of oxidized Ta as a diffusion barrier is proposed, and a HfO2/TiN/TaOX/TiAl/TiN/TiN gate stack featuring an aggressive Work Function of 4.35 eV (allowing a Work Function separation of 600 mV between NMOS and PMOS) is demonstrated. This work paves the way toward the integration of gate-last options for DRAM periphery transistors.

  3. Volcanic risk metrics at Mt Ruapehu, New Zealand: some background to a probabilistic eruption forecasting scheme and a cost/benefit analysis at an open conduit volcano

    Science.gov (United States)

    Jolly, Gill; Sandri, Laura; Lindsay, Jan; Scott, Brad; Sherburn, Steve; Jolly, Art; Fournier, Nico; Keys, Harry; Marzocchi, Warner

    2010-05-01

    The Bayesian Event Tree for Eruption Forecasting software (BET_EF) is a probabilistic model based on an event tree scheme that was created specifically to compute long- and short-term probabilities of different outcomes (volcanic unrest, magmatic unrest, eruption, vent location and eruption size) at long-time dormant and routinely monitored volcanoes. It is based on the assumption that upward movements of magma in a closed conduit volcano will produce detectable changes in the monitored parameters at the surface. In this perspective, the goal of BET_EF is to compute probabilities by merging information from geology, models, past data and present monitoring measurements, through a Bayesian inferential method. In the present study, we attempt to apply BET_EF to Mt Ruapehu, a very active and well-monitored volcano exhibiting the typical features of open conduit volcanoes. In such conditions, current monitoring at the surface is not necessarily able to detect short term changes at depth that may occur only seconds to minutes before an eruption. This results in so-called "blue sky eruptions" of Mt Ruapehu (for example in September 2007), that are volcanic eruptions apparently not preceded by any presently detectable signal in the current monitoring. A further complication at Mt Ruapehu arises from the well-developed hydrothermal system and the permanent crater lake sitting on top of the magmatic conduit. Both the hydrothermal system and crater lake may act to mask or change monitoring signals (if present) that magma produces deeper in the edifice. Notwithstanding these potential drawbacks, we think that an attempt to apply BET_EF at Ruapehu is worthwhile, for several reasons. First, with the exception of a few "blue sky" events, monitoring data at Mt Ruapehu can be helpful in forecasting major events, especially if a large amount of magma is intruded into the edifice and becomes available for phreatomagmatic or magmatic eruptions, as for example in 1995-96. Secondly, in

  4. Deprive to kill: Glutamine closes the gate to anticancer monocarboxylic drugs

    OpenAIRE

    Cardaci, Simone; Ciriolo, Maria Rosa

    2012-01-01

    Killing properties of antitumor drugs can be enhanced by strategies targeting biochemical adaptations of cancer cells. Recently, we reported that depriving cancer cells of glutamine is a feasible approach to enhance antitumor effects of the alkylating analog of pyruvic acid, 3-bromopyruvate, which rely on the induction of autophagic cell death by metabolic-oxidative stress. 3-bromopyruvate chemopotentiation is the result of its increased intracellular uptake mediated by the monocarboxylate tr...

  5. Close the Gate, Lock the Windows, Bolt the Doors: Securing Library Computers. Online Treasures

    Science.gov (United States)

    Balas, Janet

    2005-01-01

    This article, written by a systems librarian at the Monroeville Public Library, discusses a major issue affecting all computer users, security. It indicates that while, staying up-to-date on the latest security issues has become essential for all computer users, it's more critical for network managers who are responsible for securing computer…

  6. Accuracy and Consistency of Respiratory Gating in Abdominal Cancer Patients

    International Nuclear Information System (INIS)

    Ge, Jiajia; Santanam, Lakshmi; Yang, Deshan; Parikh, Parag J.

    2013-01-01

    Purpose: To evaluate respiratory gating accuracy and intrafractional consistency for abdominal cancer patients treated with respiratory gated treatment on a regular linear accelerator system. Methods and Materials: Twelve abdominal patients implanted with fiducials were treated with amplitude-based respiratory-gated radiation therapy. On the basis of daily orthogonal fluoroscopy, the operator readjusted the couch position and gating window such that the fiducial was within a setup margin (fiducial-planning target volume [f-PTV]) when RPM indicated “beam-ON.” Fifty-five pre- and post-treatment fluoroscopic movie pairs with synchronized respiratory gating signal were recorded. Fiducial motion traces were extracted from the fluoroscopic movies using a template matching algorithm and correlated with f-PTV by registering the digitally reconstructed radiographs with the fluoroscopic movies. Treatment was determined to be “accurate” if 50% of the fiducial area stayed within f-PTV while beam-ON. For movie pairs that lost gating accuracy, a MATLAB program was used to assess whether the gating window was optimized, the external-internal correlation (EIC) changed, or the patient moved between movies. A series of safety margins from 0.5 mm to 3 mm was added to f-PTV for reassessing gating accuracy. Results: A decrease in gating accuracy was observed in 44% of movie pairs from daily fluoroscopic movies of 12 abdominal patients. Three main causes for inaccurate gating were identified as change of global EIC over time (∼43%), suboptimal gating setup (∼37%), and imperfect EIC within movie (∼13%). Conclusions: Inconsistent respiratory gating accuracy may occur within 1 treatment session even with a daily adjusted gating window. To improve or maintain gating accuracy during treatment, we suggest using at least a 2.5-mm safety margin to account for gating and setup uncertainties

  7. Minding the close relationship.

    Science.gov (United States)

    Harvey, J H; Omarzu, J

    1997-01-01

    In this theoretical analysis, we argue that a process referred to as minding is essential for a couple to feel mutually close and satisfied in a close relationship over a long period Minding represents a package of mutual self-disclosure, other forms of goal-oriented behavior aimed at facilitating the relationship, and attributions about self's and other's motivations, intentions, and Mort in the relationship. Self-disclosure and attribution activities in minding are aimed at getting to know the other, trying to understand the other's motivations and deeper disposition as they pertain to the relationship, and showing respect and acceptance for knowledge gained about other. We link the concept of minding to other major ideas and literatures about how couples achieve closeness: self-disclosure and social penetration, intimacy, empathy and empathic accuracy, and love and self-expansion. We argue that the minding process articulated here has not previously been delineated and that it is a useful composite notion about essential steps in bonding among humans. We also argue that the minding concept stretches our understanding of the interface of attribution and close relationships. We present research possibilities and implications and consider possible alternative positions and counter arguments about the merits of the minding idea for close relationship satisfaction.

  8. Neural network based inspection of voids and karst conduits in hydro-electric power station tunnels using GPR

    Science.gov (United States)

    Kilic, Gokhan; Eren, Levent

    2018-04-01

    This paper reports on the fundamental role played by Ground Penetrating Radar (GPR), alongside advanced processing and presentation methods, during the tunnel boring project at a Dam and Hydro-Electric Power Station. It identifies from collected GPR data such issues as incomplete grouting and the presence of karst conduits and voids and provides full details of the procedures adopted. In particular, the application of collected GPR data to the Neural Network (NN) method is discussed.

  9. Brachial artery repair using the basilic vein as a reliable conduit in a 3-year-old child

    Directory of Open Access Journals (Sweden)

    Hyunyoung G. Kim

    2017-04-01

    Full Text Available A supracondylar fracture of the humerus is the most common upper extremity fracture in children with concurrent neurovascular complications. However, bypass grafting in the management of a pediatric open elbow dislocation with an arterial injury has rarely been reported in the literature. Hence, an adequate conduit for a vessel graft interposition remains questionable when a primary anastomosis is limited in an arterial reconstruction. The purpose of this study is to present a brachial artery reconstruction in a 3-year-old patient with an open supracondylar fracture of the humerus. In the clinical and surgical examination of the patient, an open wound in the left antecubital fossa presented with accompanying brachial artery injury. To repair the artery, a reverse end-to-end anastomosis was conducted using basilic vein graft from the ipsilateral arm under general anesthesia. The patient had palpable radial pulses in the postoperative clinical examination and was discharged without complications. The great saphenous vein (GSV has proven to be the most common and the best conduit for arterial reconstruction of the upper extremity in the adult patients. However, the GSV graft is known to have the propensity for becoming aneurysmal in pediatric patients. Some studies have demonstrated the basilic vein as a suitable conduit in pediatric patients, in that it has durable patency, fewer branches, size compatibility for anastomosis, and proximity to the brachial artery. Our case confirms the safety of using this autogenous vein from within the zone of injury for arterial reconstruction, after a supracondylar humeral fracture. The management of pediatric elbow fractures accompanying vascular injuries can be technically demanding due to relatively small, delicate structures and concurrent neurovascular network. Nonetheless, a vascular injury should be treated with high level of suspicion and immediate intervention to avoid any limb ischemia or loss. In

  10. Close binary stars

    International Nuclear Information System (INIS)

    Larsson-Leander, G.

    1979-01-01

    Studies of close binary stars are being persued more vigorously than ever, with about 3000 research papers and notes pertaining to the field being published during the triennium 1976-1978. Many major advances and spectacular discoveries were made, mostly due to increased observational efficiency and precision, especially in the X-ray, radio, and ultraviolet domains. Progress reports are presented in the following areas: observational techniques, methods of analyzing light curves, observational data, physical data, structure and models of close binaries, statistical investigations, and origin and evolution of close binaries. Reports from the Coordinates Programs Committee, the Committee for Extra-Terrestrial Observations and the Working Group on RS CVn binaries are included. (Auth./C.F.)

  11. Field observations of extended seawater intrusion through subsurface karst conduit networks at Wakulla Spring in the Woodville Karst Plain, Florida

    Science.gov (United States)

    Xu, Z.; Bassett, S.; Hu, B. X.; Dyer, S.

    2016-12-01

    Five periods of increased electrical conductivity have been found in the karst conduits supplying one of the largest first magnitude springs in Florida with water. Numerous well-developed conduit networks are distributed in the Woodville Karst Plain (WKP), Florida and connected to the Gulf of Mexico. A composite analysis of precipitation and electric conductivity data provides strong evidence that the increases in conductivity are directly tied to seawater intrusion moving inland and traveling 14 miles against the prevailing regional hydraulic gradient from from Spring Creek Spring Complex (SCSC), a group of submarine springs at the Gulf Coast. A geochemical analysis of samples from the spring vent rules out anthropogenic contamination and upwelling regional recharge from the deep aquifer as sources of the rising conductivity. The interpretation is supported by the conceptual model established by prior researchers working to characterize the study area. This abstract documented the first and longest case of seawater intrusion in the WKP, and also indicates significant possibility of seawater contamination through subsurface conduit networks in a coastal karst aquifer.

  12. Towards a Tissue-Engineered Contractile Fontan-Conduit: The Fate of Cardiac Myocytes in the Subpulmonary Circulation.

    Directory of Open Access Journals (Sweden)

    Daniel Biermann

    Full Text Available The long-term outcome of patients with single ventricles improved over time, but remains poor compared to other congenital heart lesions with biventricular circulation. Main cause for this unfavourable outcome is the unphysiological hemodynamic of the Fontan circulation, such as subnormal systemic cardiac output and increased systemic-venous pressure. To overcome this limitation, we are developing the concept of a contractile extracardiac Fontan-tunnel. In this study, we evaluated the survival and structural development of a tissue-engineered conduit under in vivo conditions. Engineered heart tissue was generated from ventricular heart cells of neonatal Wistar rats, fibrinogen and thrombin. Engineered heart tissues started beating around day 8 in vitro and remained contractile in vivo throughout the experiment. After culture for 14 days constructs were implanted around the right superior vena cava of Wistar rats (n = 12. Animals were euthanized after 7, 14, 28 and 56 days postoperatively. Hematoxylin and eosin staining showed cardiomyocytes arranged in thick bundles within the engineered heart tissue-conduit. Immunostaining of sarcomeric actin, alpha-actin and connexin 43 revealed a well -developed cardiac myocyte structure. Magnetic resonance imaging (d14, n = 3 revealed no constriction or stenosis of the superior vena cava by the constructs. Engineered heart tissues survive and contract for extended periods after implantation around the superior vena cava of rats. Generation of larger constructs is warranted to evaluate functional benefits of a contractile Fontan-conduit.

  13. Ant Colony Algorithm and Simulation for Robust Airport Gate Assignment

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-01-01

    Full Text Available Airport gate assignment is core task for airport ground operations. Due to the fact that the departure and arrival time of flights may be influenced by many random factors, the airport gate assignment scheme may encounter gate conflict and many other problems. This paper aims at finding a robust solution for airport gate assignment problem. A mixed integer model is proposed to formulate the problem, and colony algorithm is designed to solve this model. Simulation result shows that, in consideration of robustness, the ability of antidisturbance for airport gate assignment scheme has much improved.

  14. Exchange gate on the qudit space and Fock space

    International Nuclear Information System (INIS)

    Fujii, Kazuyuki

    2003-01-01

    We construct an exchange gate with small elementary gates on the space of qudits, which consist of three controlled shift gates and three 'reverse' gates. This is a natural extension of the qubit case. We also consider a similar situation in Fock space, but in this case we find some differences. However, we can construct the exchange gate by making use of a generalized coherent operator based on the Lie algebra su(2), which is a well-known method in quantum optics. We also make a brief comment on 'imperfect clones'

  15. Edge-on gating effect in molecular wires.

    Science.gov (United States)

    Lo, Wai-Yip; Bi, Wuguo; Li, Lianwei; Jung, In Hwan; Yu, Luping

    2015-02-11

    This work demonstrates edge-on chemical gating effect in molecular wires utilizing the pyridinoparacyclophane (PC) moiety as the gate. Different substituents with varied electronic demands are attached to the gate to simulate the effect of varying gating voltages similar to that in field-effect transistor (FET). It was observed that the orbital energy level and charge carrier's tunneling barriers can be tuned by changing the gating group from strong electron acceptors to strong electron donors. The single molecule conductance and current-voltage characteristics of this molecular system are truly similar to those expected for an actual single molecular transistor.

  16. Characterization of a Common-Gate Amplifier Using Ferroelectric Transistors

    Science.gov (United States)

    Hunt, Mitchell; Sayyah, Rana; MacLeod, Todd C.; Ho, Fat D.

    2011-01-01

    In this paper, the empirical data collected through experiments performed using a FeFET in the common-gate amplifier circuit is presented. The FeFET common-gate amplifier was characterized by varying all parameters in the circuit, such as load resistance, biasing of the transistor, and input voltages. Due to the polarization of the ferroelectric layer, the particular behavior of the FeFET common-gate amplifier presents interesting results. Furthermore, the differences between a FeFET common-gate amplifier and a MOSFET common-gate amplifier are examined.

  17. Ballistic transport of graphene pnp junctions with embedded local gates

    International Nuclear Information System (INIS)

    Nam, Seung-Geol; Ki, Dong-Keun; Kim, Youngwook; Kim, Jun Sung; Lee, Hu-Jong; Park, Jong Wan

    2011-01-01

    We fabricated graphene pnp devices, by embedding pre-defined local gates in an oxidized surface layer of a silicon substrate. With neither deposition of dielectric material on the graphene nor electron-beam irradiation, we obtained high-quality graphene pnp devices without degradation of the carrier mobility even in the local-gate region. The corresponding increased mean free path leads to the observation of ballistic and phase-coherent transport across a local gate 130 nm wide, which is about an order of magnitude wider than reported previously. Furthermore, in our scheme, we demonstrated independent control of the carrier density in the local-gate region, with a conductance map very much distinct from those of top-gated devices. This was caused by the electric field arising from the global back gate being strongly screened by the embedded local gate. Our scheme allows the realization of ideal multipolar graphene junctions with ballistic carrier transport.

  18. Synthesis of multivalued quantum logic circuits by elementary gates

    Science.gov (United States)

    Di, Yao-Min; Wei, Hai-Rui

    2013-01-01

    We propose the generalized controlled X (gcx) gate as the two-qudit elementary gate, and based on Cartan decomposition, we also give the one-qudit elementary gates. Then we discuss the physical implementation of these elementary gates and show that it is feasible with current technology. With these elementary gates many important qudit quantum gates can be synthesized conveniently. We provide efficient methods for the synthesis of various kinds of controlled qudit gates and greatly simplify the synthesis of existing generic multi-valued quantum circuits. Moreover, we generalize the quantum Shannon decomposition (QSD), the most powerful technique for the synthesis of generic qubit circuits, to the qudit case. A comparison of ququart (d=4) circuits and qubit circuits reveals that using ququart circuits may have an advantage over the qubit circuits in the synthesis of quantum circuits.

  19. Double-gated spectral snapshots for biomolecular fluorescence

    International Nuclear Information System (INIS)

    Nakamura, Ryosuke; Hamada, Norio; Ichida, Hideki; Tokunaga, Fumio; Kanematsu, Yasuo

    2007-01-01

    A versatile method to take femtosecond spectral snapshots of fluorescence has been developed based on a double gating technique in the combination of an optical Kerr gate and an image intensifier as an electrically driven gate set in front of a charge-coupled device detector. The application of a conventional optical-Kerr-gate method is limited to molecules with the short fluorescence lifetime up to a few hundred picoseconds, because long-lifetime fluorescence itself behaves as a source of the background signal due to insufficiency of the extinction ratio of polarizers employed for the Kerr gate. By using the image intensifier with the gate time of 200 ps, we have successfully suppressed the background signal and overcome the application limit of optical-Kerr-gate method. The system performance has been demonstrated by measuring time-resolved fluorescence spectra for laser dye solution and the riboflavin solution as a typical sample of biomolecule

  20. Water exchange and pressure transfer between conduits and matrix and their influence on hydrodynamics of two karst aquifers with sinking streams

    Science.gov (United States)

    Bailly-Comte, Vincent; Martin, Jonathan B.; Jourde, Hervé; Screaton, Elizabeth J.; Pistre, Séverin; Langston, Abigail

    2010-05-01

    SummaryKarst aquifers are heterogeneous media where conduits usually drain water from lower permeability volumes (matrix and fractures). For more than a century, various approaches have used flood recession curves, which integrate all hydrodynamic processes in a karst aquifer, to infer physical properties of the movement and storage of groundwater. These investigations typically only consider flow to the conduits and thus have lacked quantitative observations of how pressure transfer and water exchange between matrix and conduit during flooding could influence recession curves. We present analyses of simultaneous discharge and water level time series of two distinctly different karst systems, one with low porosity and permeability matrix rocks in southern France, and one with high porosity and permeability matrix rocks in north-central Florida (USA). We apply simple mathematical models of flood recession using time series representations of recharge, storage, and discharge processes in the karst aquifer. We show that karst spring hydrographs can be interpreted according to pressure transfer between two distinct components of the aquifer, conduit and matrix porosity, which induce two distinct responses at the spring. Water exchange between conduits and matrix porosity successively control the flow regime at the spring. This exchange is governed by hydraulic head differences between conduits and matrix, head gradients within conduits, and the contrast of permeability between conduits and matrix. These observations have consequences for physical interpretations of recession curves and modeling of karst spring flows, particularly for the relative magnitudes of base flow and quick flow from karst springs. Finally, these results suggest that similar analyses of recession curves can be applied to karst aquifers with distinct physical characteristics utilizing well and spring hydrograph data, but information must be known about the hydrodynamics and physical properties of

  1. Genetic algorithm based on qubits and quantum gates

    International Nuclear Information System (INIS)

    Silva, Joao Batista Rosa; Ramos, Rubens Viana

    2003-01-01

    Full text: Genetic algorithm, a computational technique based on the evolution of the species, in which a possible solution of the problem is coded in a binary string, called chromosome, has been used successfully in several kinds of problems, where the search of a minimal or a maximal value is necessary, even when local minima are present. A natural generalization of a binary string is a qubit string. Hence, it is possible to use the structure of a genetic algorithm having a sequence of qubits as a chromosome and using quantum operations in the reproduction in order to find the best solution in some problems of quantum information. For example, given a unitary matrix U what is the pair of qubits that, when applied at the input, provides the output state with maximal entanglement? In order to solve this problem, a population of chromosomes of two qubits was created. The crossover was performed applying the quantum gates CNOT and SWAP at the pair of qubits, while the mutation was performed applying the quantum gates Hadamard, Z and Not in a single qubit. The result was compared with a classical genetic algorithm used to solve the same problem. A hundred simulations using the same U matrix was performed. Both algorithms, hereafter named by CGA (classical) and QGA (using qu bits), reached good results close to 1 however, the number of generations needed to find the best result was lower for the QGA. Another problem where the QGA can be useful is in the calculation of the relative entropy of entanglement. We have tested our algorithm using 100 pure states chosen randomly. The stop criterion used was the error lower than 0.01. The main advantages of QGA are its good precision, robustness and very easy implementation. The main disadvantage is its low velocity, as happen for all kind of genetic algorithms. (author)

  2. NRC closing remarks

    International Nuclear Information System (INIS)

    Coffman, F.

    1994-01-01

    This section contains the edited transcript of the NRC closing remarks made by Mr. Franklin Coffman (Chief, Human Factors Branch, Office of Nuclear Regulatory Research) and Dr. Cecil Thomas (Deputy Director, Division of Reactor Controls and Human Factors, Office of Nuclear Reactor Regulation). This editing consisted of minimal editing to correct grammar and remove extraneous references to microphone volume, etc

  3. Rapid gated Thallium-201 perfusion SPECT - clinically feasible?

    International Nuclear Information System (INIS)

    Wadhwa, S.S.; Mansberg, R.; Fernandes, V.B.; Wilkinson, D.; Abatti, D.

    1998-01-01

    Full text: Standard dose energy window optimised Thallium-201 (Tl-201) SPECT has about half the counts of a standard dose from Technetium-99m Sestamibi (Tc99m-Mibi) gated perfusion SPECT. This study investigates the clinical feasibility of rapid energy window optimised Tl-201 gated perfusion SPECT (gated-TI) and compares quantitative left ventricular ejection fraction (LVEF) and visually assessed image quality for wall motion and thickening to analogous values obtained from Tc99m-Mibi gated perfusion SPECT (gated - mibi). Methods: We studied 60 patients with a rest gated Tl-201 SPECT (100 MBq, 77KeV peak, 34% window, 20 sec/projection) followed by a post stress gated Sestamibi SPECT (1GBq, 140KeV, 20% window, 20 sec/projection) separate dual isotope protocol. LVEF quantitation was performed using commercially available software (SPECTEF, General Electric). Visual grading of image quality for wall thickening and motion was performed using a three-point scale (excellent, good and poor). Results: LVEF for gated Tl-201 SPECT was 59.6 ± 12.0% (Mean ± SD). LVEF for gated Sestamibi SPECT was 60.4 ±11.4% (Mean ± SD). These were not significantly different (P=0.27, T-Test). There was good correlation (r=0.9) between gated-TI and gated-mibi LVEF values. The quality of gated-Tl images was ranked as excellent, good and poor in 12, 50 and 38% of the patients respectively. Image quality was better in gated-mibi SPECT, with ratings of 12, 62 and 26% respectively. Conclusion: Rapid gated Thallium-201 acquisition with energy window optimisation can be effectively performed on majority of patients and offers the opportunity to assess not only myocardial perfusion and function, as with Technetium based agents, but also viability using a single day one isotope protocol

  4. Modified conduit preparation creates a pseudosinus in an aortic valve-sparing procedure for aneurysm of the ascending aorta.

    Science.gov (United States)

    Cochran, R P; Kunzelman, K S; Eddy, A C; Hofer, B O; Verrier, E D

    1995-06-01

    Mechanical valved conduit replacement of the aortic root is a durable and appropriate procedure for many diseases of the ascending aorta, but may sacrifice an anatomically salvageable aortic valve. For young active patients and for patients with "systemic" arterial disease (atherosclerosis, Marfan's syndrome) who may require future operations, life-long anticoagulation with its attendant thromboembolic versus hemorrhagic risks is not ideal. Several techniques have been suggested as aortic valve-sparing options. Recently, a procedure was described that combines the freehand homograft techniques with the standard Bentall techniques (David procedure). This innovative technique replaces the ascending aorta with a Dacron cylinder, spares the aortic valve, and restores competence and thus offers an excellent alternative. The durability of this procedure that places the aortic valve inside a cylindrical conduit without sinuses of Valsalva is unknown. In selected patients, we have used this technique to spare the aortic valve. On the basis of experimental data and preliminary computer modeling, with the hope of improving the durability, we have modified the conduit to create a "pseudosinus" in our most recent nine patients. We have done the David procedure in 10 patients. The pseudosinus modification was done in the most recent nine patients. Patients' ages ranged from 37 to 71 years (mean 49.9 years). There were five female and five male patients. Five patients had Marfan's syndrome and five patients had annuloaortic ectasia. There has been no mortality and all patients have had both early and late follow-up echocardiography. Five patients have zero to trace aortic insufficiency, four patients have trace to mild aortic insufficiency, and one patient has mild or "1+" aortic insufficiency. Aortic insufficiency has not progressed in any patient during the 18 months of follow-up. The patient with 1+ aortic insufficiency has no activity limits, good ventricular function, and

  5. Effect of stochastic gating on channel-facilitated transport of non-interacting and strongly repelling solutes

    Science.gov (United States)

    Berezhkovskii, Alexander M.; Bezrukov, Sergey M.

    2017-08-01

    Ligand- or voltage-driven stochastic gating—the structural rearrangements by which the channel switches between its open and closed states—is a fundamental property of biological membrane channels. Gating underlies the channel's ability to respond to different stimuli and, therefore, to be functionally regulated by the changing environment. The accepted understanding of the gating effect on the solute flux through the channel is that the mean flux is the product of the flux through the open channel and the probability of finding the channel in the open state. Here, using a diffusion model of channel-facilitated transport, we show that this is true only when the gating is much slower than the dynamics of solute translocation through the channel. If this condition breaks, the mean flux could differ from this simple estimate by orders of magnitude.

  6. Structure of a prokaryotic sodium channel pore reveals essential gating elements and an outer ion binding site common to eukaryotic channels.

    Science.gov (United States)

    Shaya, David; Findeisen, Felix; Abderemane-Ali, Fayal; Arrigoni, Cristina; Wong, Stephanie; Nurva, Shailika Reddy; Loussouarn, Gildas; Minor, Daniel L

    2014-01-23

    Voltage-gated sodium channels (NaVs) are central elements of cellular excitation. Notwithstanding advances from recent bacterial NaV (BacNaV) structures, key questions about gating and ion selectivity remain. Here, we present a closed conformation of NaVAe1p, a pore-only BacNaV derived from NaVAe1, a BacNaV from the arsenite oxidizer Alkalilimnicola ehrlichei found in Mono Lake, California, that provides insight into both fundamental properties. The structure reveals a pore domain in which the pore-lining S6 helix connects to a helical cytoplasmic tail. Electrophysiological studies of full-length BacNaVs show that two elements defined by the NaVAe1p structure, an S6 activation gate position and the cytoplasmic tail "neck", are central to BacNaV gating. The structure also reveals the selectivity filter ion entry site, termed the "outer ion" site. Comparison with mammalian voltage-gated calcium channel (CaV) selectivity filters, together with functional studies, shows that this site forms a previously unknown determinant of CaV high-affinity calcium binding. Our findings underscore commonalities between BacNaVs and eukaryotic voltage-gated channels and provide a framework for understanding gating and ion permeation in this superfamily. © 2013. Published by Elsevier Ltd. All rights reserved.

  7. Comparative analysis of the pressure profilometry of vesicocutaneous continent catheterizable conduits between patients with and without rectus abdominis neosphincter (Yachia principle).

    Science.gov (United States)

    Rondon, Atila; Leslie, Bruno; Arcuri, Leonardo Javier; Ortiz, Valdemar; Macedo, Antonio

    2015-09-01

    To assess whether crossing rectus abdominis muscle strips, as proposed by Yachia, would change urinary catheterizable conduit's pressure profilometry, in static and dynamic conditions. Non-randomized selection of 20 continent patients that underwent Macedo's ileum-based reservoir, 10 including Yachia's technique (Study Group) and 10 without this mechanism of continence (Control Group). Demographics and cystometric data were assessed. Conduit's pressure profilometry was obtained by infusing saline through a multichannel catheter, at rest and during Valsalva maneuver. We assessed the pressure: (a) in the bladder; (b) in conduit's proximal segment; and (c) in conduit's distal segment, which is presumably the abdominal wall and crossed muscle strips site. Mean age at surgery was 6.1 years in the Control Group and 7.7 years in the Study Group. There was no statistically significant difference between groups regarding maximum cystometric bladder capacity and leakage point pressure. At rest, the pressure profilometry showed similar results between groups in all segments analyzed. During Valsalva maneuver, pressure profilometry showed similar results between groups in bladder and conduit's proximal segment pressure. In this condition, conduit's distal segment pressure in the Study Group (Mean = 72.9 and Peak = 128.7 cmH2 O) was significantly greater (P continence. © 2014 Wiley Periodicals, Inc.

  8. Respiration Induced Heart Motion and Indications of Gated Delivery for Left-Sided Breast Irradiation

    International Nuclear Information System (INIS)

    Qi, X. Sharon; Hu, Angela; Wang Kai; Newman, Francis; Crosby, Marcus; Hu Bin; White, Julia; Li, X. Allen

    2012-01-01

    Purpose: To investigate respiration-induced heart motion for left-sided breast irradiation using a four-dimensional computed tomography (4DCT) technique and to determine novel indications to assess heart motion and identify breast patients who may benefit from a gated treatment. Methods and Materials: Images of 4DCT acquired during free breathing for 20 left-sided breast cancer patients, who underwent whole breast irradiation with or without regional nodal irradiation, were analyzed retrospectively. Dose distributions were reconstructed in the phases of 0%, 20%, and 50%. The intrafractional heart displacement was measured in three selected transverse CT slices using D LAD (the distance from left ascending aorta to a fixed line [connecting middle point of sternum and the body] drawn on each slice) and maximum heart depth (MHD, the distance of the forefront of the heart to the line). Linear regression analysis was used to correlate these indices with mean heart dose and heart dose volume at different breathing phases. Results: Respiration-induced heart displacement resulted in observable variations in dose delivered to the heart. During a normal free-breathing cycle, heart-induced motion D LAD and MHD changed up to 9 and 11 mm respectively, resulting in up to 38% and 39% increases of mean doses and V 25.2 for the heart. MHD and D LAD were positively correlated with mean heart dose and heart dose volume. Respiratory-adapted gated treatment may better spare heart and ipsilateral-lung compared with the conventional non-gated plan in a subset of patients with large D LAD or MHD variations. Conclusion: Proposed indices offer novel assessment of heart displacement based on 4DCT images. MHD and D LAD can be used independently or jointly as selection criteria for respiratory gating procedure before treatment planning. Patients with great intrafractional MHD variations or tumor(s) close to the diaphragm may particularly benefit from the gated treatment.

  9. Dynamic load effects on gate valve operability

    International Nuclear Information System (INIS)

    Steele, R. Jr.; MacDonald, P.E.; Arendts, J.G.

    1986-01-01

    The Idaho National Engineering Laboratory (INEL) participated in an internationally sponsored seismic research program conducted at the decommissioned Heissdampfreaktor (HDR) located in the Federal Republic of Germany. An existing piping system was modified by installation of an 8-in., naturally aged, motor-operated gate valve from a US nuclear power plant and a piping support system of US design. Six other piping support systems of varying flexibility from stiff to flexible were also installed at various times during the tests. Additional valve loadings included internal hydraulic loads and, during one block of tests, elevated temperature. The operability and integrity of the aged gate valve and the dynamic response of the various piping support system were measured during 25 representative seismic events

  10. Gate Control Coefficient Effect on CNFET Characteristic

    International Nuclear Information System (INIS)

    Sanudin, Rahmat; Ma'Radzi, Ahmad Alabqari; Nayan, Nafarizal

    2009-01-01

    The development of carbon nanotube field-effect transistor (CNFET) as alternative to existing transistor technology has long been published and discussed. The emergence of this device offers new material and structure in building a transistor. This paper intends to do an analysis of gate control coefficient effect on CNFET performance. The analysis is based on simulation study of current-voltage (I-V) characteristic of ballistic CNFET. The simulation study used the MOSFET-like CNFET mathematical model to establish the device output characteristic. Based on the analysis of simulation result, it is found that the gate control coefficient contributes to a significant effect on the performance of CNFET. The result also shown the parameter could help to improve the device performance in terms of its output and response as well. Nevertheless, the characteristic of the carbon nanotube that acts as the channel is totally important in determining the performance of the transistor as a whole.

  11. Floating Gate CMOS Dosimeter With Frequency Output

    Science.gov (United States)

    Garcia-Moreno, E.; Isern, E.; Roca, M.; Picos, R.; Font, J.; Cesari, J.; Pineda, A.

    2012-04-01

    This paper presents a gamma radiation dosimeter based on a floating gate sensor. The sensor is coupled with a signal processing circuitry, which furnishes a square wave output signal, the frequency of which depends on the total dose. Like any other floating gate dosimeter, it exhibits zero bias operation and reprogramming capabilities. The dosimeter has been designed in a standard 0.6 m CMOS technology. The whole dosimeter occupies a silicon area of 450 m250 m. The initial sensitivity to a radiation dose is Hz/rad, and to temperature and supply voltage is kHz/°C and 0.067 kHz/mV, respectively. The lowest detectable dose is less than 1 rad.

  12. Water-gel for gating graphene transistors.

    Science.gov (United States)

    Kim, Beom Joon; Um, Soong Ho; Song, Woo Chul; Kim, Yong Ho; Kang, Moon Sung; Cho, Jeong Ho

    2014-05-14

    Water, the primary electrolyte in biology, attracts significant interest as an electrolyte-type dielectric material for transistors compatible with biological systems. Unfortunately, the fluidic nature and low ionic conductivity of water prevents its practical usage in such applications. Here, we describe the development of a solid state, megahertz-operating, water-based gate dielectric system for operating graphene transistors. The new electrolyte systems were prepared by dissolving metal-substituted DNA polyelectrolytes into water. The addition of these biocompatible polyelectrolytes induced hydrogelation to provide solid-state integrity to the system. They also enhanced the ionic conductivities of the electrolytes, which in turn led to the quick formation of an electric double layer at the graphene/electrolyte interface that is beneficial for modulating currents in graphene transistors at high frequencies. At the optimized conditions, the Na-DNA water-gel-gated flexible transistors and inverters were operated at frequencies above 1 MHz and 100 kHz, respectively.

  13. SWNT array resonant gate MOS transistor

    Energy Technology Data Exchange (ETDEWEB)

    Arun, A; Salet, P; Ionescu, A M [NanoLab, Ecole Polytechnique Federale de Lausanne, CH-1015, Lausanne (Switzerland); Campidelli, S; Filoramo, A; Derycke, V; Goffman, M F, E-mail: marcelo.goffman@cea.fr [Laboratoire d' Electronique Moleculaire, SPEC (CNRS URA 2454), IRAMIS, CEA, Gif-sur-Yvette (France)

    2011-02-04

    We show that thin horizontal arrays of single wall carbon nanotubes (SWNTs) suspended above the channel of silicon MOSFETs can be used as vibrating gate electrodes. This new class of nano-electromechanical system (NEMS) combines the unique mechanical and electronic properties of SWNTs with an integrated silicon-based motion detection. Its electrical response exhibits a clear signature of the mechanical resonance of SWNT arrays (120-150 MHz) showing that these thin horizontal arrays behave as a cohesive, rigid and elastic body membrane with a Young's modulus in the order of 1-10 GPa and ultra-low mass. The resonant frequency can be tuned by the gate voltage and its dependence is well understood within the continuum mechanics framework.

  14. SWNT array resonant gate MOS transistor.

    Science.gov (United States)

    Arun, A; Campidelli, S; Filoramo, A; Derycke, V; Salet, P; Ionescu, A M; Goffman, M F

    2011-02-04

    We show that thin horizontal arrays of single wall carbon nanotubes (SWNTs) suspended above the channel of silicon MOSFETs can be used as vibrating gate electrodes. This new class of nano-electromechanical system (NEMS) combines the unique mechanical and electronic properties of SWNTs with an integrated silicon-based motion detection. Its electrical response exhibits a clear signature of the mechanical resonance of SWNT arrays (120-150 MHz) showing that these thin horizontal arrays behave as a cohesive, rigid and elastic body membrane with a Young's modulus in the order of 1-10 GPa and ultra-low mass. The resonant frequency can be tuned by the gate voltage and its dependence is well understood within the continuum mechanics framework.

  15. SWNT array resonant gate MOS transistor

    International Nuclear Information System (INIS)

    Arun, A; Salet, P; Ionescu, A M; Campidelli, S; Filoramo, A; Derycke, V; Goffman, M F

    2011-01-01

    We show that thin horizontal arrays of single wall carbon nanotubes (SWNTs) suspended above the channel of silicon MOSFETs can be used as vibrating gate electrodes. This new class of nano-electromechanical system (NEMS) combines the unique mechanical and electronic properties of SWNTs with an integrated silicon-based motion detection. Its electrical response exhibits a clear signature of the mechanical resonance of SWNT arrays (120-150 MHz) showing that these thin horizontal arrays behave as a cohesive, rigid and elastic body membrane with a Young's modulus in the order of 1-10 GPa and ultra-low mass. The resonant frequency can be tuned by the gate voltage and its dependence is well understood within the continuum mechanics framework.

  16. GATE V6: a major enhancement of the GATE simulation platform enabling modelling of CT and radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Jan, S; Becheva, E [DSV/I2BM/SHFJ, Commissariat a l' Energie Atomique, Orsay (France); Benoit, D; Rehfeld, N; Stute, S; Buvat, I [IMNC-UMR 8165 CNRS-Paris 7 and Paris 11 Universities, 15 rue Georges Clemenceau, 91406 Orsay Cedex (France); Carlier, T [INSERM U892-Cancer Research Center, University of Nantes, Nantes (France); Cassol, F; Morel, C [Centre de physique des particules de Marseille, CNRS-IN2P3 and Universite de la Mediterranee, Aix-Marseille II, 163, avenue de Luminy, 13288 Marseille Cedex 09 (France); Descourt, P; Visvikis, D [INSERM, U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Brest (France); Frisson, T; Grevillot, L; Guigues, L; Sarrut, D; Zahra, N [Universite de Lyon, CREATIS, CNRS UMR5220, Inserm U630, INSA-Lyon, Universite Lyon 1, Centre Leon Berard (France); Maigne, L; Perrot, Y [Laboratoire de Physique Corpusculaire, 24 Avenue des Landais, 63177 Aubiere Cedex (France); Schaart, D R [Delft University of Technology, Radiation Detection and Medical Imaging, Mekelweg 15, 2629 JB Delft (Netherlands); Pietrzyk, U, E-mail: buvat@imnc.in2p3.fr [Reseach Center Juelich, Institute of Neurosciences and Medicine and Department of Physics, University of Wuppertal (Germany)

    2011-02-21

    GATE (Geant4 Application for Emission Tomography) is a Monte Carlo simulation platform developed by the OpenGATE collaboration since 2001 and first publicly released in 2004. Dedicated to the modelling of planar scintigraphy, single photon emission computed tomography (SPECT) and positron emission tomography (PET) acquisitions, this platform is widely used to assist PET and SPECT research. A recent extension of this platform, released by the OpenGATE collaboration as GATE V6, now also enables modelling of x-ray computed tomography and radiation therapy experiments. This paper presents an overview of the main additions and improvements implemented in GATE since the publication of the initial GATE paper (Jan et al 2004 Phys. Med. Biol. 49 4543-61). This includes new models available in GATE to simulate optical and hadronic processes, novelties in modelling tracer, organ or detector motion, new options for speeding up GATE simulations, examples illustrating the use of GATE V6 in radiotherapy applications and CT simulations, and preliminary results regarding the validation of GATE V6 for radiation therapy applications. Upon completion of extensive validation studies, GATE is expected to become a valuable tool for simulations involving both radiotherapy and imaging.

  17. Magmas in motion: Degassing in volcanic conduits and fabrics of pyroclastic density current

    Science.gov (United States)

    Burgisser, Alain

    Volcanoes are caused by the transport of magma batches from the Earth's crust to the surface. These magmas in motion undergo drastic changes of rheologic properties during their journey to the surface and this work explores how these changes affect volcanic eruptions. The first part of this study is devoted to the dynamic aspects of degassing and permeability in magmas with high pressure, high temperature experiments on natural volcanic rocks. Degassing is measured by the influence of decompression rate on the growth of the bubbles present in the magma while permeability is deduced from the temporal evolution of these bubbles. The parameterization of our results in a numerical model of volcanic conduit flow show that previous models based on equilibrium degassing overestimate the acceleration and the decompression rate of the magma. Assessing permeability effects derived form our results show that the transition between explosive and effusive eruptions is a strong function of the magma initial ascent rate. The second part of this work is a unification of two end-members of pyroclastic currents (highly concentrated pyroclastic flows and dilute, turbulent pyroclastic surges) using theoretical scaling arguments based on multiphase physics. Starting from the dynamics of the particle interactions with a fundamental eddy, we consider the full spectrum of eddies generated within a turbulent current. We demonstrate that the presence of particles with various sizes induces a density stratification of the current, leading to its segregation into a basal concentrated part overlain by a dilute cloud. To verify our predictions on the interactions of such a segregated pyroclastic current with its surroundings (hills and sea), we studied the products of the 2050 BP caldera-forming eruption of Okmok Volcano (Alaska). This field study allowed us to reconstruct the eruptive sequence and to validate the main aspects of our theoretical model, such as the superposition of a dense and

  18. Speleogenesis, geometry, and topology of caves: A quantitative study of 3D karst conduits

    Science.gov (United States)

    Jouves, Johan; Viseur, Sophie; Arfib, Bruno; Baudement, Cécile; Camus, Hubert; Collon, Pauline; Guglielmi, Yves

    2017-12-01

    Karst systems are hierarchically spatially organized three-dimensional (3D) networks of conduits behaving as drains for groundwater flow. Recently, geostatistical approaches proposed to generate karst networks from data and parameters stemming from analogous observed karst features. Other studies have qualitatively highlighted relationships between speleogenetic processes and cave patterns. However, few studies have been performed to quantitatively define these relationships. This paper reports a quantitative study of cave geometries and topologies that takes the underlying speleogenetic processes into account. In order to study the spatial organization of caves, a 3D numerical database was built from 26 caves, corresponding to 621 km of cumulative cave passages representative of the variety of karst network patterns. The database includes 3D speleological surveys for which the speleogenetic context is known, allowing the polygenic karst networks to be divided into 48 monogenic cave samples and classified into four cave patterns: vadose branchwork (VB), water-table cave (WTC), looping cave (LC), and angular maze (AM). Eight morphometric cave descriptors were calculated, four geometrical parameters (width-height ratio, tortuosity, curvature, and vertical index) and four topological ones (degree of node connectivity, α and γ graph indices, and ramification index) respectively. The results were validated by statistical analyses (Kruskal-Wallis test and PCA). The VB patterns are clearly distinct from AM ones and from a third group including WTC and LC. A quantitative database of cave morphology characteristics is provided, depending on their speleogenetic processes. These characteristics can be used to constrain and/or validate 3D geostatistical simulations. This study shows how important it is to relate the geometry and connectivity of cave networks to recharge and flow processes. Conversely, the approach developed here provides proxies to estimate the evolution of

  19. The role of external drains and peritoneal conduits in the treatment of recurrent chronic subdural hematoma.

    Science.gov (United States)

    Santarius, Thomas; Qureshi, Hammad U; Sivakumaran, Ram; Kirkpatrick, Peter J; Kirollos, Ramez W; Hutchinson, Peter J

    2010-06-01

    A considerable body of evidence supporting the use of external drainage after evacuation of primary chronic subdural hematoma (CSDH) exists in the literature. However, no systematic study of the value of postoperative drainage in the treatment of recurrent CSDH has been published. The aim of the study was to investigate external drains and subdural-to-peritoneal conduit in the treatment of recurrent CSDH. A retrospective review of cases of CSDH treated in our institution between October 2002 and October 2006 was conducted. During the study period, 408 patients had burr hole evacuation. Sixty-four patients (15.9%) had treatment for recurrence. One patient had craniotomy, and the remaining 63 had another burr hole evacuation: 36 without placement of a drain (BHO), 14 with external drainage (SED), and 13 with placement of subdural-peritoneal catheter (SPC). Fifteen patients (24%) developed a secondary recurrence requiring a third drainage procedure. Postoperative drainage (SED or SPC) was associated with a significantly lower secondary recurrence rate when compared to BHO: 3/27 (11%) versus 12/36 (33%) (χ(2), P=.040). There was no significant difference in recurrence rates between SED and SPC. Postoperative complications included acute subdural hematoma (2), subdural empyema (2), brain edema (2), pneumonia (3), and in-hospital death (2). None of the complications was associated with the use of a specific technique. The results indicate that, as in the treatment of primary CSDHs, the use of drain (SED or SPC) with burr hole evacuation is safe and is associated with lower recurrence rate. Further investigation is needed to clarify the indications of currently available surgical techniques in the treatment of recurrent CSDH. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Quantitative Analysis of Karst Conduit Structure Parameters and Hydraulic Parameters Based on Tracer Test

    Science.gov (United States)

    Qiang, Z.; Zhiqiang, Z.; Xu, M.; Jinyu, S.; Jihong, Q.

    2017-12-01

    The Old Town of Lijiang is famous as the world cultural heritage since 1997, while characterized by its ancient buildings and natural scenery, water is the soul of the town. Around Heilongtan Springs, there are a large quantity of springs at the Old Town of Lijiang , which is an important part of the World Cultural Heritage. Heilongtan Springs is 2420m above the sea level, the annual variation of the flow rate varies greatly (0 8042 x 104 m3 / year). Recharge area Jiuzihai depressions is 6km long, 3km wide and 2800m above sea level, as main karst water recharge area karst funnel and the sink hole are developing on this planation surface, in the research area medium to thick layers of limestone made up Beiya formation (T2b) of Triassic system distributed widely, karst is strongly developed and the fissure caves water occurrence. In order to exploring the application of tracer test in karst hydrogeology, a tracer test was conducted from Jiuzihai depressions to Ganze Spring. Based on the hydrogeological conditions in the study area, tracer test was used for analysis of groundwater connectivity and flow field characteristics, quantitative analysis of Tracer Breakthrough Curves (BTC) with code Qtracer2. The results demonstated that there are hydraulic connection between Jiuzihai depressions with Ganze Spring, and there are other karst conduits in this area. The longitudinal dispersivity coefficient is 0.24 m2/s, longitudinal dispersivity is 12.06m, flow-channel volume is 3.08×104 m3, flow-channel surface area is 3.27×107m2, mean diameter is 1.42m, Reynolds number is 25187, Froude number is 0.0061, respectively. The groundwater in this area is in a slow turbulent state. The results are of great significance to understand the law of groundwater migration, establish groundwater quality prediction model and exploit karst water resources effectively.

  1. Dependence of the ac loss on the aspect ratio in a cable in conduit conductor

    International Nuclear Information System (INIS)

    Cau, F; Bruzzone, P

    2010-01-01

    The coupling current loss in rectangular superconducting cables is strictly dependent on their aspect ratio, which has an impact on the area linked by the field variation and consequently on the currents induced between strands. The relation between the ac loss and aspect ratio is studied with reference to the testing of three short cable in conduit conductor (CICC) samples at the SULTAN test facility. The first conductor is a 25 kA NbTi cable for the JT60-SA tokamak; the second is a 20 kA Nb 3 Sn cable for the HZB hybrid magnet. The last CICC is a 68 kA Nb 3 Sn cable with layout similar to that of the ITER toroidal field (TF) conductor (called the 'European toroidal field (EUTF) alternate'). All the samples are assembled with two conductor sections differing only in their orientation with respect to the external variable field. In the first and third samples, the cable of one leg is rotated by 90 0 , while in the HZB sample it is rotated by 45 0 with respect to the other leg. The ac loss is measured at the SULTAN test facility using a gas flow calorimetric method. A sample length of 39 cm is exposed to a sinusoidal field with an amplitude of ± 0.3 or ± 0.2 T (depending on the superconductor) and frequency variable in the range 0.1-0.8 Hz. A background field of 2 T perpendicular both to the sinusoidal field and to the sample axis is also applied. The ac loss is assessed by measuring the variation of the He enthalpy, assuming the metal enthalpy to be negligible. The loss curve for both legs is discussed in terms of the respective aspect ratios and the results, including data from former test campaigns, are compared with the aim of finding an analytical relation between the loss and the conductor dimensions.

  2. Nanopatterned acellular valve conduits drive the commitment of blood-derived multipotent cells

    Directory of Open Access Journals (Sweden)

    Di Liddo R

    2016-10-01

    Full Text Available Rosa Di Liddo,1,2 Paola Aguiari,3 Silvia Barbon,1,2 Thomas Bertalot,1 Amit Mandoli,1 Alessia Tasso,1 Sandra Schrenk,1 Laura Iop,3 Alessandro Gandaglia,3 Pier Paolo Parnigotto,2 Maria Teresa Conconi,1,2 Gino Gerosa31Department of Pharmaceutical and Pharmacological Sciences, University of Padova, 2Foundation for Biology and Regenerative Medicine, Tissue Engineering and Signaling ONLUS, 3Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova, Italy Abstract: Considerable progress has been made in recent years toward elucidating the correlation among nanoscale topography, mechanical properties, and biological behavior of cardiac valve substitutes. Porcine TriCol scaffolds are promising valve tissue engineering matrices with demonstrated self-repopulation potentiality. In order to define an in vitro model for investigating the influence of extracellular matrix signaling on the growth pattern of colonizing blood-derived cells, we cultured circulating multipotent cells (CMC on acellular aortic (AVL and pulmonary (PVL valve conduits prepared with TriCol method and under no-flow condition. Isolated by our group from Vietnamese pigs before heart valve prosthetic implantation, porcine CMC revealed high proliferative abilities, three-lineage differentiative potential, and distinct hematopoietic/endothelial and mesenchymal properties. Their interaction with valve extracellular matrix nanostructures boosted differential messenger RNA expression pattern and morphologic features on AVL compared to PVL, while promoting on both matrices the commitment to valvular and endothelial cell-like phenotypes. Based on their origin from peripheral blood, porcine CMC are hypothesized in vivo to exert a pivotal role to homeostatically replenish valve cells and contribute to hetero- or allograft colonization. Furthermore, due to their high responsivity to extracellular matrix nanostructure signaling, porcine CMC could be useful for a preliminary

  3. Spatial resolution of transport parameters in a subtropical karst conduit system during dry and wet seasons

    Science.gov (United States)

    Ender, Anna; Goeppert, Nadine; Goldscheider, Nico

    2018-04-01

    Karst aquifers are characterized by a high degree of hydrologic variability and spatial heterogeneity of transport parameters. Tracer tests allow the quantification of these parameters, but conventional point-to-point experiments fail to capture spatiotemporal variations of flow and transport. The goal of this study was to elucidate the spatial distribution of transport parameters in a karst conduit system at different flow conditions. Therefore, six tracer tests were conducted in an active and accessible cave system in Vietnam during dry and wet seasons. Injections and monitoring were done at five sites along the flow system: a swallow hole, two sites inside the cave, and two springs draining the system. Breakthrough curves (BTCs) were modeled with CXTFIT software using the one-dimensional advection-dispersion model and the two-region nonequilibrium model. In order to obtain transport parameters in the individual sections of the system, a multi-pulse injection approach was used, which was realized by using the BTCs from one section as input functions for the next section. Major findings include: (1) In the entire system, mean flow velocities increase from 183 to 1,043 m/h with increasing discharge, while (2) the proportion of immobile fluid regions decrease; (3) the lowest dispersivity was found at intermediate discharge; (4) in the individual cave sections, flow velocities decrease along the flow direction, related to decreasing gradients, while (5) dispersivity is highest in the middle section of the cave. The obtained results provide a valuable basis for the development of an adapted water management strategy for a projected water-supply system.

  4. Fibulin-4 is essential for maintaining arterial wall integrity in conduit but not muscular arteries.

    Science.gov (United States)

    Halabi, Carmen M; Broekelmann, Thomas J; Lin, Michelle; Lee, Vivian S; Chu, Mon-Li; Mecham, Robert P

    2017-05-01

    Homozygous or compound heterozygous mutations in fibulin-4 ( FBLN4 ) lead to autosomal recessive cutis laxa type 1B (ARCL1B), a multisystem disorder characterized by significant cardiovascular abnormalities, including abnormal elastin assembly, arterial tortuosity, and aortic aneurysms. We sought to determine the consequences of a human disease-causing mutation in FBLN4 (E57K) on the cardiovascular system and vascular elastic fibers in a mouse model of ARCL1B. Fbln4 E57K/E57K mice were hypertensive and developed arterial elongation, tortuosity, and ascending aortic aneurysms. Smooth muscle cell organization within the arterial wall of large conducting vessels was abnormal, and elastic fibers were fragmented and had a moth-eaten appearance. In contrast, vessel wall structure and elastic fiber integrity were normal in resistance/muscular arteries (renal, mesenteric, and saphenous). Elastin cross-linking and total elastin content were unchanged in large or small arteries, whereas elastic fiber architecture was abnormal in large vessels. While the E57K mutation did not affect Fbln4 mRNA levels, FBLN4 protein was lower in the ascending aorta of mutant animals compared to wild-type arteries but equivalent in mesenteric arteries. We found a differential role of FBLN4 in elastic fiber assembly, where it functions mainly in large conduit arteries. These results suggest that elastin assembly has different requirements depending on vessel type. Normal levels of elastin cross-links in mutant tissue call into question FBLN4's suggested role in mediating lysyl oxidase-elastin interactions. Future studies investigating tissue-specific elastic fiber assembly may lead to novel therapeutic interventions for ARCL1B and other disorders of elastic fiber assembly.

  5. Experimental and theoretical fracture mechanics applied to volcanic conduits and domes

    Science.gov (United States)

    Sammonds, P.; Matthews, C.; Kilburn, C.; Smith, R.; Tuffen, H.; Meredith, P.

    2008-12-01

    We present an integrated modelling and experimental approach to magma deformation and fracture, which we attempt to validate against field observations of seismicity. The importance of fracture processes in magma ascent dynamics and lava dome growth and collapse are apparent from the associated seismicity. Our laboratory experiments have shown that brittle fracture of magma can occur at high temperature and stress conditions prevalent in the shallow volcanic system. Here, we use a fracture mechanics approach to model seismicity preceding volcanic eruptions. Starting with the fracture mechanics concept of a crack in an elastic body, we model crack growth around the volcanic conduit through the processes of crack interactions, leading either to the propagation and linkage of cracks, or crack avoidance and the inhibition of crack propagation. The nature of that interaction is governed by the temperature and plasticity of the magma. We find that fracture mechanics rules can account for the style of seismicity preceding eruptions. We have derived the changes in seismic b-value predicted by the model and interpret these in terms of the style of fracturing, fluid flow and heat transport. We compare our model with results from our laboratory experiments where we have deformed lava at high temperatures under triaxial stresses. These experiments were conducted in dry and water saturated conditions at effective pressures up to 10 MPa, temperatures up to 1000°C and strain rates from 10-4 s-1 to 10-6 s-1. The behaviour of these magmas was largely brittle under these conditions. We monitored the acoustic emission emitted and calculate the change in micro-seismic b-value with deformation. These we find are in accord with volcano seismicity and our fracture mechanics model.

  6. Time scales of foam stability in shallow conduits: Insights from analogue experiments

    Science.gov (United States)

    Spina, L.; Scheu, B.; Cimarelli, C.; Arciniega-Ceballos, A.; Dingwell, D. B.

    2016-10-01

    Volcanic systems can exhibit periodical trends in degassing activity, characterized by a wide range of time scales. Understanding the dynamics that control such periodic behavior can provide a picture of the processes occurring in the feeding system. Toward this end, we analyzed the periodicity of outgassing in a series of decompression experiments performed on analogue material (argon-saturated silicone oil plus glass beads/fibers) scaled to serve as models of basaltic magma. To define the effects of liquid viscosity and crystal content on the time scale of outgassing, we investigated both: (1) pure liquid systems, at differing viscosities (100 and 1000 Pa s), and (2) particle-bearing suspensions (diluted and semidiluted). The results indicate that under dynamic conditions (e.g., decompressive bubble growth and fluid ascent within the conduit), the periodicity of foam disruption may be up to several orders of magnitude less than estimates based on the analysis of static conditions. This difference in foam disruption time scale is inferred to result from the contribution of bubble shear and bubble growth to inter-bubble film thinning. The presence of particles in the semidiluted regime is further linked to shorter bubble bursting times, likely resulting from contributions of the presence of a solid network and coalescence processes to the relative increase in bubble breakup rates. Finally, it is argued that these experiments represent a good analogue of gas-piston activity (i.e., the periodical rise-and-fall of a basaltic lava lake surface), implying a dominant role for shallow foam accumulation as a source process for these phenomena.

  7. Probabilistic implementation of Hadamard and unitary gates

    International Nuclear Information System (INIS)

    Song Wei; Yang Ming; Cao Zhuoliang

    2004-01-01

    We show that the Hadamard and unitary gates could be implemented by a unitary evolution together with a measurement for any unknown state chosen from a set A={ vertical bar Ψi>, vertical bar Ψ-bar i>} (i=1,2) if and only if vertical bar Ψ1>, vertical bar Ψ2>, vertical bar Ψ-bar 1>, vertical bar Ψ-bar 2> are linearly independent. We also derive the best transformation efficiencies

  8. Robust gates for holonomic quantum computation

    International Nuclear Information System (INIS)

    Florio, Giuseppe; Pascazio, Saverio; Facchi, Paolo; Fazio, Rosario; Giovannetti, Vittorio

    2006-01-01

    Non-Abelian geometric phases are attracting increasing interest because of possible experimental application in quantum computation. We study the effects of the environment (modeled as an ensemble of harmonic oscillators) on a holonomic transformation and write the corresponding master equation. The solution is analytically and numerically investigated and the behavior of the fidelity analyzed: fidelity revivals are observed and an optimal finite operation time is determined at which the gate is most robust against noise

  9. Gated Detection Measurements of Phosphorescence Lifetimes

    Directory of Open Access Journals (Sweden)

    Yordan Kostov

    2004-10-01

    Full Text Available A low-cost, gated system for measurements of phosphorescence lifetimes is presented. An extensive description of the system operating principles and metrological characteristics is given. Remarkably, the system operates without optical filtering of the LED excitation source. A description of a practical system is also given and its performance is discussed. Because the device effectively suppresses high-level background fluorescence and scattered light, it is expected to find wide-spread application in bioprocess, environmental and biomedical fields.

  10. Molecular sensors and molecular logic gates

    International Nuclear Information System (INIS)

    Georgiev, N.; Bojinov, V.

    2013-01-01

    Full text: The rapid grow of nanotechnology field extended the concept of a macroscopic device to the molecular level. Because of this reason the design and synthesis of (supra)-molecular species capable of mimicking the functions of macroscopic devices are currently of great interest. Molecular devices operate via electronic and/or nuclear rearrangements and, like macroscopic devices, need energy to operate and communicate between their elements. The energy needed to make a device work can be supplied as chemical energy, electrical energy, or light. Luminescence is one of the most useful techniques to monitor the operation of molecular-level devices. This fact determinates the synthesis of novel fluorescence compounds as a considerable and inseparable part of nanoscience development. Further miniaturization of semiconductors in electronic field reaches their limit. Therefore the design and construction of molecular systems capable of performing complex logic functions is of great scientific interest now. In semiconductor devices the logic gates work using binary logic, where the signals are encoded as 0 and 1 (low and high current). This process is executable on molecular level by several ways, but the most common are based on the optical properties of the molecule switches encoding the low and high concentrations of the input guest molecules and the output fluorescent intensities with binary 0 and 1 respectively. The first proposal to execute logic operations at the molecular level was made in 1988, but the field developed only five years later when the analogy between molecular switches and logic gates was experimentally demonstrated by de Silva. There are seven basic logic gates: AND, OR, XOR, NOT, NAND, NOR and XNOR and all of them were achieved by molecules, the fluorescence switching as well. key words: fluorescence, molecular sensors, molecular logic gates

  11. Modeling Electrolytically Top-Gated Graphene

    Directory of Open Access Journals (Sweden)

    Mišković ZL

    2010-01-01

    Full Text Available Abstract We investigate doping of a single-layer graphene in the presence of electrolytic top gating. The interfacial phenomenon is modeled using a modified Poisson–Boltzmann equation for an aqueous solution of simple salt. We demonstrate both the sensitivity of graphene’s doping levels to the salt concentration and the importance of quantum capacitance that arises due to the smallness of the Debye screening length in the electrolyte.

  12. Re-opening of Gate C

    CERN Multimedia

    TS-FM Group

    2006-01-01

    From 3rd April to 1st December 2006, Gate C (Satigny) will be open to pedestrians and vehicles (except delivery vehicles) from Monday to Friday, excluding official holidays, between 8.00 a.m. and 9.00 a.m. for those entering the site and between 5.00 p.m. and 6.00 p.m. for those leaving the site. TS-FM Group Reception and Access Control Service

  13. Re-opening of Gate C

    CERN Multimedia

    2006-01-01

    From 3rd April to 1st December 2006, Gate C (Satigny) will be open to pedestrians and vehicles (except delivery vehicles) from Mondays to Fridays, excluding official holidays, between 8.00 a.m. and 9.00 a.m. for those entering the site and between 5.00 p.m. and 6.00 p.m. for those leaving the site. TS-FM Group Reception and Access Control Service

  14. Sensorimotor gating deficits in multiple system atrophy

    DEFF Research Database (Denmark)

    Zoetmulder, Marielle; Biernat, Heidi Bryde; Nikolic, Miki

    2014-01-01

    Prepulse inhibition (PPI) of the auditory blink reflex is a measure of sensorimotor gating, which reflects an organism's ability to filter out irrelevant sensory information. PPI has never been studied in patients with multiple system atrophy (MSA), although sensorimotor deficits are frequently a...... associated with synucleinopathies. We investigated whether alterations in PPI were more pronounced in MSA compared with Parkinson's disease (PD), idiopathic rapid eye movement sleep behavior disorder (iRBD) and healthy controls....

  15. Cluster computing software for GATE simulations

    International Nuclear Information System (INIS)

    Beenhouwer, Jan de; Staelens, Steven; Kruecker, Dirk; Ferrer, Ludovic; D'Asseler, Yves; Lemahieu, Ignace; Rannou, Fernando R.

    2007-01-01

    Geometry and tracking (GEANT4) is a Monte Carlo package designed for high energy physics experiments. It is used as the basis layer for Monte Carlo simulations of nuclear medicine acquisition systems in GEANT4 Application for Tomographic Emission (GATE). GATE allows the user to realistically model experiments using accurate physics models and time synchronization for detector movement through a script language contained in a macro file. The downside of this high accuracy is long computation time. This paper describes a platform independent computing approach for running GATE simulations on a cluster of computers in order to reduce the overall simulation time. Our software automatically creates fully resolved, nonparametrized macros accompanied with an on-the-fly generated cluster specific submit file used to launch the simulations. The scalability of GATE simulations on a cluster is investigated for two imaging modalities, positron emission tomography (PET) and single photon emission computed tomography (SPECT). Due to a higher sensitivity, PET simulations are characterized by relatively high data output rates that create rather large output files. SPECT simulations, on the other hand, have lower data output rates but require a long collimator setup time. Both of these characteristics hamper scalability as a function of the number of CPUs. The scalability of PET simulations is improved here by the development of a fast output merger. The scalability of SPECT simulations is improved by greatly reducing the collimator setup time. Accordingly, these two new developments result in higher scalability for both PET and SPECT simulations and reduce the computation time to more practical values

  16. Patient training in respiratory-gated radiotherapy

    International Nuclear Information System (INIS)

    Kini, Vijay R.; Vedam, Subrahmanya S.; Keall, Paul J.; Patil, Sumukh; Chen, Clayton; Mohan, Radhe

    2003-01-01

    Respiratory gating is used to counter the effects of organ motion during radiotherapy for chest tumors. The effects of variations in patient breathing patterns during a single treatment and from day to day are unknown. We evaluated the feasibility of using patient training tools and their effect on the breathing cycle regularity and reproducibility during respiratory-gated radiotherapy. To monitor respiratory patterns, we used a component of a commercially available respiratory-gated radiotherapy system (Real Time Position Management (RPM) System, Varian Oncology Systems, Palo Alto, CA 94304). This passive marker video tracking system consists of reflective markers placed on the patient's chest or abdomen, which are detected by a wall-mounted video camera. Software installed on a PC interfaced to this camera detects the marker motion digitally and records it. The marker position as a function of time serves as the motion signal that may be used to trigger imaging or treatment. The training tools used were audio prompting and visual feedback, with free breathing as a control. The audio prompting method used instructions to 'breathe in' or 'breathe out' at periodic intervals deduced from patients' own breathing patterns. In the visual feedback method, patients were shown a real-time trace of their abdominal wall motion due to breathing. Using this, they were asked to maintain a constant amplitude of motion. Motion traces of the abdominal wall were recorded for each patient for various maneuvers. Free breathing showed a variable amplitude and frequency. Audio prompting resulted in a reproducible frequency; however, the variability and the magnitude of amplitude increased. Visual feedback gave a better control over the amplitude but showed minor variations in frequency. We concluded that training improves the reproducibility of amplitude and frequency of patient breathing cycles. This may increase the accuracy of respiratory-gated radiation therapy

  17. LRET Determination of Molecular Distances during pH Gating of the Mammalian Inward Rectifier Kir1.1b.

    Science.gov (United States)

    Nanazashvili, Mikheil; Sánchez-Rodríguez, Jorge E; Fosque, Ben; Bezanilla, Francisco; Sackin, Henry

    2018-01-09

    Gating of the mammalian inward rectifier Kir1.1 at the helix bundle crossing (HBC) by intracellular pH is believed to be mediated by conformational changes in the C-terminal domain (CTD). However, the exact motion of the CTD during Kir gating remains controversial. Crystal structures and single-molecule fluorescence resonance energy transfer of KirBac channels have implied a rigid body rotation and/or a contraction of the CTD as possible triggers for opening of the HBC gate. In our study, we used lanthanide-based resonance energy transfer on single-Cys dimeric constructs of the mammalian renal inward rectifier, Kir1.1b, incorporated into anionic liposomes plus PIP 2 , to determine unambiguous, state-dependent distances between paired Cys residues on diagonally opposite subunits. Functionality and pH dependence of our proteoliposome channels were verified in separate electrophysiological experiments. The lanthanide-based resonance energy transfer distances measured in closed (pH 6) and open (pH 8) conditions indicated neither expansion nor contraction of the CTD during gating, whereas the HBC gate widened by 8.8 ± 4 Å, from 6.3 ± 2 to 15.1 ± 6 Å, during opening. These results are consistent with a Kir gating model in which rigid body rotation of the large CTD around the permeation axis is correlated with opening of the HBC hydrophobic gate, allowing permeation of a 7 Å hydrated K ion. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  18. A method for evaluating pressure locking and thermal binding of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Dogan, T.

    1996-12-01

    A method is described to evaluate the susceptibility of gate valves to pressure locking and thermal binding. Binding of the valve disc in the closed position due to high pressure water trapped in the bonnet cavity (pressure locking) or differential thermal expansion of the disk in the seat (thermal binding) represents a potential mechanism that can prevent safety-related systems from functioning when called upon. The method described here provides a general equation that can be applied to a given gate valve design and set of operating conditions to determine the susceptibility of the valve to fail due to disc binding. The paper is organized into three parts. The first part discusses the physical mechanisms that cause disc binding. The second part describes the mathematical equations. The third part discusses the conclusions.

  19. Distribution and function of voltage-gated sodium channels in the nervous system.

    Science.gov (United States)

    Wang, Jun; Ou, Shao-Wu; Wang, Yun-Jie

    2017-11-02

    Voltage-gated sodium channels (VGSCs) are the basic ion channels for neuronal excitability, which are crucial for the resting potential and the generation and propagation of action potentials in neurons. To date, at least nine distinct sodium channel isoforms have been detected in the nervous system. Recent studies have identified that voltage-gated sodium channels not only play an essential role in the normal electrophysiological activities of neurons but also have a close relationship with neurological diseases. In this study, the latest research findings regarding the structure, type, distribution, and function of VGSCs in the nervous system and their relationship to neurological diseases, such as epilepsy, neuropathic pain, brain tumors, neural trauma, and multiple sclerosis, are reviewed in detail.

  20. Physical implication of transition voltage in organic nano-floating-gate nonvolatile memories

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shun; Gao, Xu, E-mail: wangsd@suda.edu.cn, E-mail: gaoxu@suda.edu.cn; Zhong, Ya-Nan; Zhang, Zhong-Da; Xu, Jian-Long; Wang, Sui-Dong, E-mail: wangsd@suda.edu.cn, E-mail: gaoxu@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu 215123 (China)

    2016-07-11

    High-performance pentacene-based organic field-effect transistor nonvolatile memories, using polystyrene as a tunneling dielectric and Au nanoparticles as a nano-floating-gate, show parallelogram-like transfer characteristics with a featured transition point. The transition voltage at the transition point corresponds to a threshold electric field in the tunneling dielectric, over which stored electrons in the nano-floating-gate will start to leak out. The transition voltage can be modulated depending on the bias configuration and device structure. For p-type active layers, optimized transition voltage should be on the negative side of but close to the reading voltage, which can simultaneously achieve a high ON/OFF ratio and good memory retention.

  1. Tuning the magnetoresistance of ultrathin WTe2 sheets by electrostatic gating.

    Science.gov (United States)

    Na, Junhong; Hoyer, Alexander; Schoop, Leslie; Weber, Daniel; Lotsch, Bettina V; Burghard, Marko; Kern, Klaus

    2016-11-10

    The semimetallic, two-dimensional layered transition metal dichalcogenide WTe 2 has raised considerable interest due to its huge, non-saturating magnetoresistance. While for the origin of this effect, a close-to-ideal balance of electrons and holes has been put forward, the carrier concentration dependence of the magnetoresistance remains to be clarified. Here, we present a detailed study of the magnetotransport behaviour of ultrathin, mechanically exfoliated WTe 2 sheets as a function of electrostatic back gating. The carrier concentration and mobility, determined using the two band model and analysis of the Shubnikov-de Haas oscillations, indicate enhanced surface scattering for the thinnest sheets. By the back gate action, the magnetoresistance could be tuned by up to ∼100% for a ∼13 nm-thick WTe 2 sheet.

  2. Engineering integrated photonics for heralded quantum gates.

    Science.gov (United States)

    Meany, Thomas; Biggerstaff, Devon N; Broome, Matthew A; Fedrizzi, Alessandro; Delanty, Michael; Steel, M J; Gilchrist, Alexei; Marshall, Graham D; White, Andrew G; Withford, Michael J

    2016-06-10

    Scaling up linear-optics quantum computing will require multi-photon gates which are compact, phase-stable, exhibit excellent quantum interference, and have success heralded by the detection of ancillary photons. We investigate the design, fabrication and characterisation of the optimal known gate scheme which meets these requirements: the Knill controlled-Z gate, implemented in integrated laser-written waveguide arrays. We show device performance to be less sensitive to phase variations in the circuit than to small deviations in the coupler reflectivity, which are expected given the tolerance values of the fabrication method. The mode fidelity is also shown to be less sensitive to reflectivity and phase errors than the process fidelity. Our best device achieves a fidelity of 0.931 ± 0.001 with the ideal 4 × 4 unitary circuit and a process fidelity of 0.680 ± 0.005 with the ideal computational-basis process.

  3. Three-channel gated nanosecond integrator

    International Nuclear Information System (INIS)

    Tsirkel', B.I.; Martsinovskij, A.M.

    1981-01-01

    Structure and principle of operation of three-channel gated integrator for investigating the shape of periodical electric and optical signals at high background noise level are described. The integrator consists of an integrating circuit itself for each channel and a circuit of gating pulse formation. If the noise level doesn't exceed the signal, the value of storage capacity can be equal to 22 nF. The value of storage capacity must be increased in the case of a worse signal-to-noise ratio. The gating pulse formation circuit includes a comparator, a sawtooth voltage generator and a reference voltage generator. An integrator flowsheet is given. The time resolution of the system is about 50 ns, time sweep amounts to 5-2000 μs, electric signal sensitivity is about 70 μV. The pulse signal shape recording is performed with manual or automated time sweep at two-coordinate potentiometer. The light signal detection is made on the base of photomultiplier pulse counting rate record by the dynamic capacitor method, sensitivity limit amounts to about 1 pulse/s

  4. Engineering integrated photonics for heralded quantum gates

    Science.gov (United States)

    Meany, Thomas; Biggerstaff, Devon N.; Broome, Matthew A.; Fedrizzi, Alessandro; Delanty, Michael; Steel, M. J.; Gilchrist, Alexei; Marshall, Graham D.; White, Andrew G.; Withford, Michael J.

    2016-06-01

    Scaling up linear-optics quantum computing will require multi-photon gates which are compact, phase-stable, exhibit excellent quantum interference, and have success heralded by the detection of ancillary photons. We investigate the design, fabrication and characterisation of the optimal known gate scheme which meets these requirements: the Knill controlled-Z gate, implemented in integrated laser-written waveguide arrays. We show device performance to be less sensitive to phase variations in the circuit than to small deviations in the coupler reflectivity, which are expected given the tolerance values of the fabrication method. The mode fidelity is also shown to be less sensitive to reflectivity and phase errors than the process fidelity. Our best device achieves a fidelity of 0.931 ± 0.001 with the ideal 4 × 4 unitary circuit and a process fidelity of 0.680 ± 0.005 with the ideal computational-basis process.

  5. Towards Self-Clocked Gated OCDMA Receiver

    Science.gov (United States)

    Idris, S.; Osadola, T.; Glesk, I.

    2013-02-01

    A novel incoherent OCDMA receiver with incorporated all-optical clock recovery for self-synchronization of a time gate for the multi access interferences (MAI) suppression and minimizing the effect of data time jitter in incoherent OCDMA system was successfully developed and demonstrated. The solution was implemented and tested in a multiuser environment in an out of the laboratory OCDMA testbed with two-dimensional wavelength-hopping time-spreading coding scheme and OC-48 (2.5 Gbp/s) data rate. The self-clocked all-optical time gate uses SOA-based fibre ring laser optical clock, recovered all-optically from the received OCDMA traffic to control its switching window for cleaning the autocorrelation peak from the surrounding MAI. A wider eye opening was achieved when the all-optically recovered clock from received data was used for synchronization if compared to a static approach with the RF clock being generated by a RF synthesizer. Clean eye diagram was also achieved when recovered clock is used to drive time gating.

  6. Opening of the New Gate E (Reminder)

    CERN Multimedia

    Relations with the Host States Service

    2004-01-01

    Since 1 November 2004, members of the CERN personnel holding a legitimation document issued by the Swiss Federal Department of Foreign Affairs may use Gate E ("Charles de Gaulle Gate"), located at the West end of the Meyrin Site, from Monday to Friday, except on official CERN holidays, from 7.30 a.m. to 9.30 a.m. to enter the site and from 4.30 p.m. to 6.30 p.m. to leave the site. All persons using Gate E must automatically present for inspection by the Guard on duty: either their azure B-type CERN access card (the letter B precedes the identification number printed on the card); or, during a transitional period lasting until 17 December 2004, their blue C-type CERN access card (the letter C precedes the identification number printed on the card) and their legitimation document issued by the Swiss Federal Department of Foreign Affairs («Carte de légitimation» or «Attestation de fonctions»). The new azure B-type CERN access card is issued, where appropria...

  7. Direct Structural Identification of Gas Induced Gate-Opening Coupled with Commensurate Adsorption in a Microporous Metal-Organic Framework.

    Science.gov (United States)

    Banerjee, Debasis; Wang, Hao; Plonka, Anna M; Emge, Thomas J; Parise, John B; Li, Jing

    2016-08-08

    Gate-opening is a unique and interesting phenomenon commonly observed in flexible porous frameworks, where the pore characteristics and/or crystal structures change in response to external stimuli such as adding or removing guest molecules. For gate-opening that is induced by gas adsorption, the pore-opening pressure often varies for different adsorbate molecules and, thus, can be applied to selectively separate a gas mixture. The detailed understanding of this phenomenon is of fundamental importance to the design of industrially applicable gas-selective sorbents, which remains under investigated due to the lack of direct structural evidence for such systems. We report a mechanistic study of gas-induced gate-opening process of a microporous metal-organic framework, [Mn(ina)2 ] (ina=isonicotinate) associated with commensurate adsorption, by a combination of several analytical techniques including single crystal X-ray diffraction, in situ powder X-ray diffraction coupled with differential scanning calorimetry (XRD-DSC), and gas adsorption-desorption methods. Our study reveals that the pronounced and reversible gate opening/closing phenomena observed in [Mn(ina)2 ] are coupled with a structural transition that involves rotation of the organic linker molecules as a result of interaction of the framework with adsorbed gas molecules including carbon dioxide and propane. The onset pressure to open the gate correlates with the extent of such interaction. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Validation of a simultaneous PET/MR system model for PET simulation using GATE

    International Nuclear Information System (INIS)

    Monnier, Florian; Fayad, Hadi; Bert, Julien; Schmidt, Holger; Visvikis, Dimitris

    2015-01-01

    Simultaneous PET/MR acquisition shows promise in a range of applications. Simulation using GATE is an essential tool that allows obtaining the ground truth for such acquisitions and therefore helping in the development and the validation of innovative processing methods such as PET image reconstruction, attenuation correction and motion correction. The purpose of this work is to validate the GATE simulation of the Siemens Biograph mMR PET/MR system. A model of the Siemens Biograph mMR was developed. This model includes the geometry and spatial positioning of the crystals inside the scanner and the characteristics of the detection process. The accuracy of the model was tested by comparing, on a real physical phantom study, GATE simulated results to reconstructed PET images using measured results obtained from a Siemens Biograph mMR system. The same parameters such as the acquisition time and phantom position inside the scanner were fixed for our simulations. List-mode outputs were recovered in both cases and reconstructed using the OPL-EM algorithm. Several parameters were used to compare the two reconstructed images such as profile comparison, signal-to-noise ratio and activity contrast analysis. Finally patient acquired MR images were segmented and used for the simulation of corresponding PET images. The simulated and acquired sets of reconstructed phantom images showed close emission values in regions of interest with relative differences lower than 5%. The scatter fraction was within a <3% agreement. Close matching of profiles and contrast indices were obtained between simulated and corresponding acquired PET images. Our results indicate that the GATE developed Biograph mMR model is accurate in comparison to the real scanner performance and can be used for evaluating innovative processing methods for applications in clinical PET/MR protocols.

  9. Closing the loop.

    Science.gov (United States)

    Dassau, E; Atlas, E; Phillip, M

    2010-02-01

    The dream of closing the loop is actually the dream of creating an artificial pancreas and freeing the patients from being involved with the care of their own diabetes. Insulin-dependent diabetes (type 1) is a chronic incurable disease which requires constant therapy without the possibility of any 'holidays' or insulin-free days. It means that patients have to inject insulin every day of their life, several times per day, and in order to do it safely they also have to measure their blood glucose levels several times per day. Patients need to plan their meals, their physical activities and their insulin regime - there is only very small room for spontaneous activities. This is why the desire for an artificial pancreas is so strong despite the fact that it will not cure the diabetic patients. Attempts to develop a closed-loop system started in the 1960s but never got to a clinical practical stage of development. In recent years the availability of continuous glucose sensors revived those efforts and stimulated the clinician and researchers to believe that closing the loop might be possible nowadays. Many papers have been published over the years describing several different ideas on how to close the loop. Most of the suggested systems have a sensing arm that measures the blood glucose repeatedly or continuously, an insulin delivery arm that injects insulin upon command and a computer that makes the decisions of when and how much insulin to deliver. The differences between the various published systems in the literature are mainly in their control algorithms. However, there are also differences related to the method and site of glucose measurement and insulin delivery. SC glucose measurements and insulin delivery are the most studied option but other combinations of insulin measurements and glucose delivery including intravascular and intraperitoneal (IP) are explored. We tried to select recent publications that we believe had influenced and inspired people interested

  10. Probing Dense Sprays with Gated, Picosecond, Digital Particle Field Holography

    Directory of Open Access Journals (Sweden)

    James Trolinger

    2011-12-01

    Full Text Available This paper describes work that demonstrated the feasibility of producing a gated digital holography system that is capable of producing high-resolution images of three-dimensional particle and structure details deep within dense particle fields of a spray. We developed a gated picosecond digital holocamera, using optical Kerr cell gating, to demonstrate features of gated digital holography that make it an exceptional candidate for this application. The Kerr cell gate shuttered the camera after the initial burst of ballistic and snake photons had been recorded, suppressing longer path, multiple scattered illumination. By starting with a CW laser without gating and then incorporating a picosecond laser and an optical Kerr gate, we were able to assess the imaging quality of the gated holograms, and determine improvement gained by gating. We produced high quality images of 50–200 μm diameter particles, hairs and USAF resolution charts from digital holograms recorded through turbid media where more than 98% of the light was scattered from the field. The system can gate pulses as short as 3 mm in pathlength (10 ps, enabling image-improving features of the system. The experiments lead us to the conclusion that this method has an excellent capability as a diagnostics tool in dense spray combustion research.

  11. Free energy dissipation of the spontaneous gating of a single voltage-gated potassium channel.

    Science.gov (United States)

    Wang, Jia-Zeng; Wang, Rui-Zhen

    2018-02-01

    Potassium channels mainly contribute to the resting potential and re-polarizations, with the potassium electrochemical gradient being maintained by the pump Na + /K + -ATPase. In this paper, we construct a stochastic model mimicking the kinetics of a potassium channel, which integrates temporal evolving of the membrane voltage and the spontaneous gating of the channel. Its stationary probability density functions (PDFs) are found to be singular at the boundaries, which result from the fact that the evolving rates of voltage are greater than the gating rates of the channel. We apply PDFs to calculate the power dissipations of the potassium current, the leakage, and the gating currents. On a physical perspective, the essential role of the system is the K + -battery charging the leakage (L-)battery. A part of power will inevitably be dissipated among the process. So, the efficiency of energy transference is calculated.

  12. Free energy dissipation of the spontaneous gating of a single voltage-gated potassium channel

    Science.gov (United States)

    Wang, Jia-Zeng; Wang, Rui-Zhen

    2018-02-01

    Potassium channels mainly contribute to the resting potential and re-polarizations, with the potassium electrochemical gradient being maintained by the pump Na+/K+-ATPase. In this paper, we construct a stochastic model mimicking the kinetics of a potassium channel, which integrates temporal evolving of the membrane voltage and the spontaneous gating of the channel. Its stationary probability density functions (PDFs) are found to be singular at the boundaries, which result from the fact that the evolving rates of voltage are greater than the gating rates of the channel. We apply PDFs to calculate the power dissipations of the potassium current, the leakage, and the gating currents. On a physical perspective, the essential role of the system is the K+-battery charging the leakage (L-)battery. A part of power will inevitably be dissipated among the process. So, the efficiency of energy transference is calculated.

  13. Analysis of gate underlap channel double gate MOS transistor for electrical detection of bio-molecules

    Science.gov (United States)

    Ajay; Narang, Rakhi; Saxena, Manoj; Gupta, Mridula

    2015-12-01

    In this paper, an analytical model for gate drain underlap channel Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor (DG-MOSFET) for label free electrical detection of biomolecules has been proposed. The conformal mapping technique has been used to derive the expressions for surface potential, lateral electric field, energy bands (i.e. conduction and valence band) and threshold voltage (Vth). Subsequently a full drain current model to analyze the sensitivity of the biosensor has been developed. The shift in the threshold voltage and drain current (after the biomolecules interaction with the gate underlap channel region of the MOS transistor) has been used as a sensing metric. All the characteristic trends have been verified through ATLAS (SILVACO) device simulation results.

  14. Voltage-Gated Potassium Channels: A Structural Examination of Selectivity and Gating

    Science.gov (United States)

    Kim, Dorothy M.; Nimigean, Crina M.

    2016-01-01

    Voltage-gated potassium channels play a fundamental role in the generation and propagation of the action potential. The discovery of these channels began with predictions made by early pioneers, and has culminated in their extensive functional and structural characterization by electrophysiological, spectroscopic, and crystallographic studies. With the aid of a variety of crystal structures of these channels, a highly detailed picture emerges of how the voltage-sensing domain reports changes in the membrane electric field and couples this to conformational changes in the activation gate. In addition, high-resolution structural and functional studies of K+ channel pores, such as KcsA and MthK, offer a comprehensive picture on how selectivity is achieved in K+ channels. Here, we illustrate the remarkable features of voltage-gated potassium channels and explain the mechanisms used by these machines with experimental data. PMID:27141052

  15. Gate tunneling current and quantum capacitance in metal-oxide-semiconductor devices with graphene gate electrodes

    Science.gov (United States)

    An, Yanbin; Shekhawat, Aniruddh; Behnam, Ashkan; Pop, Eric; Ural, Ant

    2016-11-01

    Metal-oxide-semiconductor (MOS) devices with graphene as the metal gate electrode, silicon dioxide with thicknesses ranging from 5 to 20 nm as the dielectric, and p-type silicon as the semiconductor are fabricated and characterized. It is found that Fowler-Nordheim (F-N) tunneling dominates the gate tunneling current in these devices for oxide thicknesses of 10 nm and larger, whereas for devices with 5 nm oxide, direct tunneling starts to play a role in determining the total gate current. Furthermore, the temperature dependences of the F-N tunneling current for the 10 nm devices are characterized in the temperature range 77-300 K. The F-N coefficients and the effective tunneling barrier height are extracted as a function of temperature. It is found that the effective barrier height decreases with increasing temperature, which is in agreement with the results previously reported for conventional MOS devices with polysilicon or metal gate electrodes. In addition, high frequency capacitance-voltage measurements of these MOS devices are performed, which depict a local capacitance minimum under accumulation for thin oxides. By analyzing the data using numerical calculations based on the modified density of states of graphene in the presence of charged impurities, it is shown that this local minimum is due to the contribution of the quantum capacitance of graphene. Finally, the workfunction of the graphene gate electrode is extracted by determining the flat-band voltage as a function of oxide thickness. These results show that graphene is a promising candidate as the gate electrode in metal-oxide-semiconductor devices.

  16. Inverse agonist-like action of cadmium on G-protein-gated inward-rectifier K+ channels

    International Nuclear Information System (INIS)

    Inanobe, Atsushi; Matsuura, Takanori; Nakagawa, Atsushi; Kurachi, Yoshihisa

    2011-01-01

    Highlights: → We examined allosteric control of K + channel gating. → We identified a high-affinity site for Cd 2+ to inhibit Kir3.2 activity. → The 6-coordination geometry supports the binding. → Cd 2+ inhibits Kir3.2 by trapping the conformation in the closed state. -- Abstract: The gate at the pore-forming domain of potassium channels is allosterically controlled by a stimulus-sensing domain. Using Cd 2+ as a probe, we examined the structural elements responsible for gating in an inward-rectifier K + channel (Kir3.2). One of four endogenous cysteines facing the cytoplasm contributes to a high-affinity site for inhibition by internal Cd 2+ . Crystal structure of its cytoplasmic domain in complex with Cd 2+ reveals that octahedral coordination geometry supports the high-affinity binding. This mode of action causes the tethering of the N-terminus to CD loop in the stimulus-sensing domain, suggesting that their conformational changes participate in gating and Cd 2+ inhibits Kir3.2 by trapping the conformation in the closed state like 'inverse agonist'.

  17. Inverse agonist-like action of cadmium on G-protein-gated inward-rectifier K{sup +} channels

    Energy Technology Data Exchange (ETDEWEB)

    Inanobe, Atsushi, E-mail: inanobe@pharma2.med.osaka-u.ac.jp [Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka (Japan); Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka (Japan); Matsuura, Takanori [Laboratory of Protein Informatics, Institute for Protein Research, Osaka University, Osaka (Japan); Nakagawa, Atsushi [Laboratory of Supramolecular Crystallography, Institute for Protein Research, Osaka University, Osaka (Japan); Kurachi, Yoshihisa, E-mail: ykurachi@pharma2.med.osaka-u.ac.jp [Department of Pharmacology, Graduate School of Medicine, Osaka University, Osaka (Japan); Center for Advanced Medical Engineering and Informatics, Osaka University, Osaka (Japan)

    2011-04-08

    Highlights: {yields} We examined allosteric control of K{sup +} channel gating. {yields} We identified a high-affinity site for Cd{sup 2+} to inhibit Kir3.2 activity. {yields} The 6-coordination geometry supports the binding. {yields} Cd{sup 2+} inhibits Kir3.2 by trapping the conformation in the closed state. -- Abstract: The gate at the pore-forming domain of potassium channels is allosterically controlled by a stimulus-sensing domain. Using Cd{sup 2+} as a probe, we examined the structural elements responsible for gating in an inward-rectifier K{sup +} channel (Kir3.2). One of four endogenous cysteines facing the cytoplasm contributes to a high-affinity site for inhibition by internal Cd{sup 2+}. Crystal structure of its cytoplasmic domain in complex with Cd{sup 2+} reveals that octahedral coordination geometry supports the high-affinity binding. This mode of action causes the tethering of the N-terminus to CD loop in the stimulus-sensing domain, suggesting that their conformational changes participate in gating and Cd{sup 2+} inhibits Kir3.2 by trapping the conformation in the closed state like 'inverse agonist'.

  18. Onset of Spin Polarization in Four-Gate Quantum Point Contacts

    Science.gov (United States)

    Jones, Alex

    A series of simulations which utilize a Non-equilibrium Green's function (NEGF) formalism is suggested which can provide indirect evidence of the fine and non-local electrostatic tuning of the onset of spin polarization in two closely spaced quantum point contacts (QPCs) that experience a phenomenon known as lateral spin-orbit coupling (LSOC). Each of the QPCs that create the device also has its own pair of side gates (SGs) which are in-plane with the device channel. Numerical simulations of the conductance of the two closely spaced QPCs or four-gate QPC are carried out for different biasing conditions applied to two leftmost and rightmost SGs. Conductance plots are then calculated as a function of the variable, Vsweep, which is the common sweep voltage applied to the QPC. When Vsweep is only applied to two of the four side gates, the plots show several conductance anomalies, i.e., below G0 = 2e2/h, characterized by intrinsic bistability, i.e., hysteresis loops due to a difference in the conductance curves for forward and reverse common voltage sweep simulations. The appearance of hysteresis loops is attributed to the co-existence of multistable spin textures in the narrow channel of the four-gate QPC. The shape, location, and number of hysteresis loops are very sensitive to the biasing conditions on the four SGs. The shape and size of the conductance anomalies and hysteresis loops are shown to change when the biasing conditions on the leftmost and rightmost SGs are swapped, a rectifying behavior providing an additional indirect evidence for the onset of spontaneous spin polarization in nanoscale devices made of QPCs. The results of the simulations reveal that the occurrence and fine tuning of conductance anomalies in QPC structures are highly sensitive to the non-local action of closely spaced SGs. It is therefore imperative to take into account this proximity effect in the design of all electrical spin valves making use of middle gates to fine tune the spin

  19. Reconfigurable chaotic logic gates based on novel chaotic circuit

    International Nuclear Information System (INIS)

    Behnia, S.; Pazhotan, Z.; Ezzati, N.; Akhshani, A.

    2014-01-01

    Highlights: • A novel method for implementing logic gates based on chaotic maps is introduced. • The logic gates can be implemented without any changes in the threshold voltage. • The chaos-based logic gates may serve as basic components of future computing devices. - Abstract: The logical operations are one of the key issues in today’s computer architecture. Nowadays, there is a great interest in developing alternative ways to get the logic operations by chaos computing. In this paper, a novel implementation method of reconfigurable logic gates based on one-parameter families of chaotic maps is introduced. The special behavior of these chaotic maps can be utilized to provide same threshold voltage for all logic gates. However, there is a wide interval for choosing a control parameter for all reconfigurable logic gates. Furthermore, an experimental implementation of this nonlinear system is presented to demonstrate the robustness of computing capability of chaotic circuits

  20. ECG-gating in non-cardiac digital subtraction angiography

    International Nuclear Information System (INIS)

    Gattoni, F.; Baldini, V.; Cairo, F.

    1987-01-01

    This paper reports the results of the ECG-gating in non-cardiac digital subtraction angiography (DSA). One hundred and fifteen patients underwent DSA (126 examinations); ECG-gating was applied in 66/126 examinations: images recorded at 70% of R wave were subtracted. Artifacts produced by vascular movements were evaluated in all patients: only 40 examinations, carried out whithout ECG-gating, showed vascular artifacts. The major advantage of the ECG-gated DSA is the more efficent subtraction because of the better images superimposition: therefore, ECG-gating can be clinically helpful. On the contrary, it could be a problem in arrhytmic or bradycardic patients. ECG-gating is helpful in DSA imaging of the thoracic and abdominal aorta and of the cervical and renal arteries. In the examinations of peripheral vessels of the limbs it is not so efficent as in the trunk or in the neck