WorldWideScience

Sample records for gradient elution mode

  1. Different elution modes and field programming in gravitational field-flow fractionation: Field programming using density and viscosity gradients

    Czech Academy of Sciences Publication Activity Database

    Plocková, Jana; Chmelík, Josef

    2006-01-01

    Roč. 1118, č. 2 (2006), s. 253-260 ISSN 0021-9673 R&D Projects: GA MZe QD1005 Institutional research plan: CEZ:AV0Z40310501 Keywords : gravitational field flow fractionation * focusing elution mode * carrier liquid density Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.554, year: 2006

  2. Different elution modes and field programming in gravitational field-flow fractionation. III. Field programming by flow-rate gradient generated by a programmable pump.

    Science.gov (United States)

    Plocková, J; Chmelík, J

    2001-05-25

    Gravitational field-flow fractionation (GFFF) utilizes the Earth's gravitational field as an external force that causes the settlement of particles towards the channel accumulation wall. Hydrodynamic lift forces oppose this action by elevating particles away from the channel accumulation wall. These two counteracting forces enable modulation of the resulting force field acting on particles in GFFF. In this work, force-field programming based on modulating the magnitude of hydrodynamic lift forces was implemented via changes of flow-rate, which was accomplished by a programmable pump. Several flow-rate gradients (step gradients, linear gradients, parabolic, and combined gradients) were tested and evaluated as tools for optimization of the separation of a silica gel particle mixture. The influence of increasing amount of sample injected on the peak resolution under flow-rate gradient conditions was also investigated. This is the first time that flow-rate gradients have been implemented for programming of the resulting force field acting on particles in GFFF.

  3. Different elution modes and field programming in gravitational field-flow fractionation. III. Field programming by flow-rate gradient generated by a programmable pump

    Czech Academy of Sciences Publication Activity Database

    Plocková, Jana; Chmelík, Josef

    2001-01-01

    Roč. 918, č. 2 (2001), s. 361-370 ISSN 0021-9673 R&D Projects: GA AV ČR IAA4031805 Institutional research plan: CEZ:AV0Z4031919 Keywords : field-flow fractionation * field programming * flow-rate gradients Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.793, year: 2001

  4. Retention prediction and separation optimization under multilinear gradient elution in liquid chromatography with Microsoft Excel macros.

    Science.gov (United States)

    Fasoula, S; Zisi, Ch; Gika, H; Pappa-Louisi, A; Nikitas, P

    2015-05-22

    A package of Excel VBA macros have been developed for modeling multilinear gradient retention data obtained in single or double gradient elution mode by changing organic modifier(s) content and/or eluent pH. For this purpose, ten chromatographic models were used and four methods were adopted for their application. The methods were based on (a) the analytical expression of the retention time, provided that this expression is available, (b) the retention times estimated using the Nikitas-Pappa approach, (c) the stepwise approximation, and (d) a simple numerical approximation involving the trapezoid rule for integration of the fundamental equation for gradient elution. For all these methods, Excel VBA macros have been written and implemented using two different platforms; the fitting and the optimization platform. The fitting platform calculates not only the adjustable parameters of the chromatographic models, but also the significance of these parameters and furthermore predicts the analyte elution times. The optimization platform determines the gradient conditions that lead to the optimum separation of a mixture of analytes by using the Solver evolutionary mode, provided that proper constraints are set in order to obtain the optimum gradient profile in the minimum gradient time. The performance of the two platforms was tested using experimental and artificial data. It was found that using the proposed spreadsheets, fitting, prediction, and optimization can be performed easily and effectively under all conditions. Overall, the best performance is exhibited by the analytical and Nikitas-Pappa's methods, although the former cannot be used under all circumstances. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Alternative sample-introduction technique to avoid breakthrough in gradient-elution liquid chromatography of polymers

    NARCIS (Netherlands)

    Reingruber, E.; Bedani, F.; Buchberger, W.; Schoenmakers, P.

    2010-01-01

    Gradient-elution liquid chromatography (GELC) is a powerful tool for the characterization of synthetic polymers. However, gradient-elution chromatograms often suffer from breakthrough phenomena. Breakthrough can be averted by using a sample solvent as weak as the mobile phase. However, this approach

  6. Gradient elution behavior of proteins in hydrophobic interaction chromatography with U-shaped retention factor curves.

    Science.gov (United States)

    Creasy, Arch; Lomino, Joseph; Barker, Gregory; Khetan, Anurag; Carta, Giorgio

    2018-04-27

    Protein retention in hydrophobic interaction chromatography is described by the solvophobic theory as a function of the kosmostropic salt concentration. In general, an increase in salt concentration drives protein partitioning to the hydrophobic surface while a decrease reduces it. In some cases, however, protein retention also increases at low salt concentrations resulting in a U-shaped retention factor curve. During gradient elution the salt concentration is gradually decreased from a high value thereby reducing the retention factor and increasing the protein chromatographic velocity. For these conditions, a steep gradient can overtake the protein in the column, causing it to rebind. Two dynamic models, one based on the local equilibrium theory and the other based on the linear driving force approximation, are presented. We show that the normalized gradient slope determines whether the protein elutes in the gradient, partially elutes, or is trapped in the column. Experimental results are presented for two different monoclonal antibodies and for lysozyme on Capto Phenyl (High Sub) resin. One of the mAbs and lysozyme exhibit U-shaped retention factor curves and for each, we determine the critical gradient slope beyond which 100% recovery is no longer possible. Elution with a reverse gradient is also demonstrated at low salt concentrations for these proteins. Understanding this behavior has implications in the design of gradient elution since the gradient slope impacts protein recovery. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Evaluation of differences between dual salt-pH gradient elution and mono gradient elution using a thermodynamic model: Simultaneous separation of six monoclonal antibody charge and size variants on preparative-scale ion exchange chromatographic resin.

    Science.gov (United States)

    Lee, Yi Feng; Jöhnck, Matthias; Frech, Christian

    2018-02-21

    The efficiencies of mono gradient elution and dual salt-pH gradient elution for separation of six mAb charge and size variants on a preparative-scale ion exchange chromatographic resin are compared in this study. Results showed that opposite dual salt-pH gradient elution with increasing pH gradient and simultaneously decreasing salt gradient is best suited for the separation of these mAb charge and size variants on Eshmuno ® CPX. Besides giving high binding capacity, this type of opposite dual salt-pH gradient also provides better resolved mAb variant peaks and lower conductivity in the elution pools compared to single pH or salt gradients. To have a mechanistic understanding of the differences in mAb variants retention behaviors of mono pH gradient, parallel dual salt-pH gradient, and opposite dual salt-pH gradient, a linear gradient elution model was used. After determining the model parameters using the linear gradient elution model, 2D plots were used to show the pH and salt dependencies of the reciprocals of distribution coefficient, equilibrium constant, and effective ionic capacity of the mAb variants in these gradient elution systems. Comparison of the 2D plots indicated that the advantage of opposite dual salt-pH gradient system with increasing pH gradient and simultaneously decreasing salt gradient is the noncontinuous increased acceleration of protein migration. Furthermore, the fitted model parameters can be used for the prediction and optimization of mAb variants separation in dual salt-pH gradient and step elution. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018. © 2018 American Institute of Chemical Engineers.

  8. Monitoring of originated polymer in pure monomer with gradient polymer elution chromatography (GPEC)

    NARCIS (Netherlands)

    Staal, W.J.; Cools, P.J.C.H.; Herk, van A.M.; German, A.L.

    1994-01-01

    The anal. of the amt. of polymer in pure monomer with cloudpoint measurements gives only a qual. answer. Now by use of a liq. chromatograph and gradient elution a fully automated detn. the amt. of polymer can be measured and an impression of the molar mass can be achieved

  9. Microchip electrospray: improvements in spray and signal stability during gradient elution by an inverted postcolumn makeup flow.

    Science.gov (United States)

    Jung, Stephanie; Effelsberg, Uwe; Tallarek, Ulrich

    2011-12-01

    Dynamic changes in mobile phase composition during high-performance liquid chromatography (HPLC) gradient elution coupled to mass spectrometry (MS) sensitively affect electrospray modes. We investigate the impact of the eluent composition on spray stability and MS response by infusion and injection experiments with a small tetrapeptide in water-acetonitrile mixtures. The employed HPLC/electrospray (ESI)-MS configuration uses a microchip equipped with an enrichment column, a separation column, and a makeup flow (MUF) channel. One nano pump is connected to the separation column, while a second one delivers solvent of exactly inverted composition to the MUF channel. Both solvent streams are united behind the separation column, before the ESI tip, such that the resulting electrosprayed solution always has identical composition during a gradient elution. Analyte peak parameters without and with MUF compensation are determined and discussed with respect to the electrospray mode and eluent composition. The postcolumn MUF significantly improves spray and signal stability over the entire solvent gradient, without compromising the performance of the HPLC separation column. It can also be conveniently implemented on microchip platforms.

  10. Tearing modes with pressure gradient effect in pair plasmas

    International Nuclear Information System (INIS)

    Cai Huishan; Li Ding; Zheng Jian

    2009-01-01

    The general dispersion relation of tearing mode with pressure gradient effect in pair plasmas is derived analytically. If the pressure gradients of positron and electron are not identical in pair plasmas, the pressure gradient has significant influence at tearing mode in both collisionless and collisional regimes. In collisionless regime, the effects of pressure gradient depend on its magnitude. For small pressure gradient, the growth rate of tearing mode is enhanced by pressure gradient. For large pressure gradient, the growth rate is reduced by pressure gradient. The tearing mode can even be stabilized if pressure gradient is large enough. In collisional regime, the growth rate of tearing mode is reduced by the pressure gradient. While the positron and electron have equal pressure gradient, tearing mode is not affected by pressure gradient in pair plasmas.

  11. Multiple dual mode counter-current chromatography with variable duration of alternating phase elution steps.

    Science.gov (United States)

    Kostanyan, Artak E; Erastov, Andrey A; Shishilov, Oleg N

    2014-06-20

    The multiple dual mode (MDM) counter-current chromatography separation processes consist of a succession of two isocratic counter-current steps and are characterized by the shuttle (forward and back) transport of the sample in chromatographic columns. In this paper, the improved MDM method based on variable duration of alternating phase elution steps has been developed and validated. The MDM separation processes with variable duration of phase elution steps are analyzed. Basing on the cell model, analytical solutions are developed for impulse and non-impulse sample loading at the beginning of the column. Using the analytical solutions, a calculation program is presented to facilitate the simulation of MDM with variable duration of phase elution steps, which can be used to select optimal process conditions for the separation of a given feed mixture. Two options of the MDM separation are analyzed: 1 - with one-step solute elution: the separation is conducted so, that the sample is transferred forward and back with upper and lower phases inside the column until the desired separation of the components is reached, and then each individual component elutes entirely within one step; 2 - with multi-step solute elution, when the fractions of individual components are collected in over several steps. It is demonstrated that proper selection of the duration of individual cycles (phase flow times) can greatly increase the separation efficiency of CCC columns. Experiments were carried out using model mixtures of compounds from the GUESSmix with solvent systems hexane/ethyl acetate/methanol/water. The experimental results are compared to the predictions of the theory. A good agreement between theory and experiment has been demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Prediction of the retention of s-triazines in reversed-phase high-performance liquid chromatography under linear gradient-elution conditions.

    Science.gov (United States)

    D'Archivio, Angelo Antonio; Maggi, Maria Anna; Ruggieri, Fabrizio

    2014-08-01

    In this paper, a multilayer artificial neural network is used to model simultaneously the effect of solute structure and eluent concentration profile on the retention of s-triazines in reversed-phase high-performance liquid chromatography under linear gradient elution. The retention data of 24 triazines, including common herbicides and their metabolites, are collected under 13 different elution modes, covering the following experimental domain: starting acetonitrile volume fraction ranging between 40 and 60% and gradient slope ranging between 0 and 1% acetonitrile/min. The gradient parameters together with five selected molecular descriptors, identified by quantitative structure-retention relationship modelling applied to individual separation conditions, are the network inputs. Predictive performance of this model is evaluated on six external triazines and four unseen separation conditions. For comparison, retention of triazines is modelled by both quantitative structure-retention relationships and response surface methodology, which describe separately the effect of molecular structure and gradient parameters on the retention. Although applied to a wider variable domain, the network provides a performance comparable to that of the above "local" models and retention times of triazines are modelled with accuracy generally better than 7%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Reduction of Solvent Effect in Reverse Phase Gradient Elution LC-ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Patrick Allen [Iowa State Univ., Ames, IA (United States)

    2005-12-17

    %-35% (simulated) and 8%-32% (actual). Quadrupole (low resolution) and sector field (high resolution) ICP-MS instrumentation were utilized in these studies. Once an AIS pair is determined, quantification studies can be performed. First, an analysis is performed by adding both elements of the AIS pair post-column while performing the gradient elution without sample injection. A comparison of the ratio of the measured intensities to the atomic ratio of the two standards is used to determine a correction factor that can be used to account for the matrix effects caused by the mobile phase. Then, organic and/or biological molecules containing one of the two elements in the AIS pair are injected into the LC column. A gradient method is used to vary the methanol-water mixture in the mobile phase and to separate out the compounds in a given sample. A standard solution of the second ion in the AIS pair is added continuously post-column. By comparing the ratio of the measured intensities to the atomic ratio of the eluting compound and internal standard, the concentration of the injected compound can be determined.

  14. Magnon dark modes and gradient memory.

    Science.gov (United States)

    Zhang, Xufeng; Zou, Chang-Ling; Zhu, Na; Marquardt, Florian; Jiang, Liang; Tang, Hong X

    2015-11-16

    Extensive efforts have been expended in developing hybrid quantum systems to overcome the short coherence time of superconducting circuits by introducing the naturally long-lived spin degree of freedom. Among all the possible materials, single-crystal yttrium iron garnet has shown up recently as a promising candidate for hybrid systems, and various highly coherent interactions, including strong and even ultrastrong coupling, have been demonstrated. One distinct advantage in these systems is that spins form well-defined magnon modes, which allows flexible and precise tuning. Here we demonstrate that by dissipation engineering, a non-Markovian interaction dynamics between the magnon and the microwave cavity photon can be achieved. Such a process enables us to build a magnon gradient memory to store information in the magnon dark modes, which decouple from the microwave cavity and thus preserve a long lifetime. Our findings provide a promising approach for developing long-lifetime, multimode quantum memories.

  15. Optimization of elution salt concentration in stepwise elution of protein chromatography using linear gradient elution data. Reducing residual protein A by cation-exchange chromatography in monoclonal antibody purification.

    Science.gov (United States)

    Ishihara, Takashi; Kadoya, Toshihiko; Endo, Naomi; Yamamoto, Shuichi

    2006-05-05

    Our simple method for optimization of the elution salt concentration in stepwise elution was applied to the actual protein separation system, which involves several difficulties such as detection of the target. As a model separation system, reducing residual protein A by cation-exchange chromatography in human monoclonal antibody (hMab) purification was chosen. We carried out linear gradient elution experiments and obtained the data for the peak salt concentration of hMab and residual protein A, respectively. An enzyme-linked immunosorbent assay was applied to the measurement of the residual protein A. From these data, we calculated the distribution coefficient of the hMab and the residual protein A as a function of salt concentration. The optimal salt concentration of stepwise elution to reduce the residual protein A from the hMab was determined based on the relationship between the distribution coefficient and the salt concentration. Using the optimized condition, we successfully performed the separation, resulting in high recovery of hMab and the elimination of residual protein A.

  16. Simulation of elution profiles in liquid chromatography - II: Investigation of injection volume overload under gradient elution conditions applied to second dimension separations in two-dimensional liquid chromatography.

    Science.gov (United States)

    Stoll, Dwight R; Sajulga, Ray W; Voigt, Bryan N; Larson, Eli J; Jeong, Lena N; Rutan, Sarah C

    2017-11-10

    An important research direction in the continued development of two-dimensional liquid chromatography (2D-LC) is to improve the detection sensitivity of the method. This is especially important in applications where injection of large volumes of effluent from the first dimension ( 1 D) column into the second dimension ( 2 D) column leads to severe 2 D peak broadening and peak shape distortion. For example, this is common when coupling two reversed-phase columns and the organic solvent content of the 1 D mobile phase overwhelms the 2 D column with each injection of 1 D effluent, leading to low resolution in the second dimension. In a previous study we validated a simulation approach based on the Craig distribution model and adapted from the work of Czok and Guiochon [1] that enabled accurate simulation of simple isocratic and gradient separations with very small injection volumes, and isocratic separations with mismatched injection and mobile phase solvents [2]. In the present study we have extended this simulation approach to simulate separations relevant to 2D-LC. Specifically, we have focused on simulating 2 D separations where gradient elution conditions are used, there is mismatch between the sample solvent and the starting point in the gradient elution program, injection volumes approach or even exceed the dead volume of the 2 D column, and the extent of sample loop filling is varied. To validate this simulation we have compared results from simulations and experiments for 101 different conditions, including variation in injection volume (0.4-80μL), loop filling level (25-100%), and degree of mismatch between sample organic solvent and the starting point in the gradient elution program (-20 to +20% ACN). We find that that the simulation is accurate enough (median errors in retention time and peak width of -1.0 and -4.9%, without corrections for extra-column dispersion) to be useful in guiding optimization of 2D-LC separations. However, this requires that real

  17. Quality by Design in the development of hydrophilic interaction liquid chromatography method with gradient elution for the analysis of olanzapine.

    Science.gov (United States)

    Tumpa, Anja; Stajić, Ana; Jančić-Stojanović, Biljana; Medenica, Mirjana

    2017-02-05

    This paper deals with the development of hydrophilic interaction liquid chromatography (HILIC) method with gradient elution, in accordance with Analytical Quality by Design (AQbD) methodology, for the first time. The method is developed for olanzapine and its seven related substances. Following step by step AQbD methodology, firstly as critical process parameters (CPPs) temperature, starting content of aqueous phase and duration of linear gradient are recognized, and as critical quality attributes (CQAs) separation criterion S of critical pairs of substances are investigated. Rechtschaffen design is used for the creation of models that describe the dependence between CPPs and CQAs. The design space that is obtained at the end is used for choosing the optimal conditions (set point). The method is fully validated at the end to verify the adequacy of the chosen optimal conditions and applied to real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Coupled ion temperature gradient and trapped electron mode to electron temperature gradient mode gyrokinetic simulations

    International Nuclear Information System (INIS)

    Waltz, R. E.; Candy, J.; Fahey, M.

    2007-01-01

    Electron temperature gradient (ETG) transport is conventionally defined as the electron energy transport at high wave number (high-k) where ions are adiabatic and there can be no ion energy or plasma transport. Previous gyrokinetic simulations have assumed adiabatic ions (ETG-ai) and work on the small electron gyroradius scale. However such ETG-ai simulations with trapped electrons often do not have well behaved nonlinear saturation unless fully kinetic ions (ki) and proper ion scale zonal flow modes are included. Electron energy transport is separated into ETG-ki at high-k and ion temperature gradient-trapped electron mode (ITG/TEM) at low-k. Expensive (more computer-intensive), high-resolution, large-ion-scale flux-tube simulations coupling ITG/TEM and ETG-ki turbulence are presented. These require a high effective Reynolds number R≡[k(max)/k(min)] 2 =μ 2 , where μ=[ρ si /ρ si ] is the ratio of ion to electron gyroradii. Compute times scale faster than μ 3 . By comparing the coupled expensive simulations with (1) much cheaper (less compute-intensive), uncoupled, high-resolution, small, flux-tube ETG-ki and with (2) uncoupled low-resolution, large, flux-tube ITG/TEM simulations, and also by artificially turning ''off'' the low-k or high-k drives, it appears that ITG/TEM and ETG-ki transport are not strongly coupled so long as ETG-ki can access some nonadiabatic ion scale zonal flows and both high-k and low-k are linearly unstable. However expensive coupled simulations are required for physically accurate k-spectra of the transport and turbulence. Simulations with μ≥30 appear to represent the physical range μ>40. ETG-ki transport measured in ion gyro-Bohm units is weakly dependent on μ. For the mid-radius core tokamak plasma parameters studied, ETG-ki is about 10% of the electron energy transport, which in turn is about 30% of the total energy transport (with negligible ExB shear). However at large ExB shear sufficient to quench the low-k ITG

  19. Numerical study of ion thermal gradient driven modes

    International Nuclear Information System (INIS)

    Garbet, X.; Laurent, L.; Mourgues, F.; Samain, A.

    1987-01-01

    Anomalous ion thermal confinement has been observed in tokamaks (1). The ion temperature gradient driven modes could provide a possible explanation of this fact. The goal of this paper is to examine the stability of such modes by a linear, analytical and numerical study. The value of the threshold parameter and the radial profiles of the modes are computed. The effects of the particles vertical drift due to the field curvature are discussed

  20. Fast Gradient Elution Reversed-Phase HPLC with Diode-Array Detection as a High Throughput Screening Method for Drugs of Abuse

    Energy Technology Data Exchange (ETDEWEB)

    Peter W. Carr; K.M. Fuller; D.R. Stoll; L.D. Steinkraus; M.S. Pasha; Glenn G. Hardin

    2005-12-30

    A new approach has been developed by modifying a conventional gradient elution liquid chromatograph for the high throughput screening of biological samples to detect the presence of regulated intoxicants. The goal of this work was to improve the speed of a gradient elution screening method over current approaches by optimizing the operational parameters of both the column and the instrument without compromising the reproducibility of the retention times, which are the basis for the identification. Most importantly, the novel instrument configuration substantially reduces the time needed to re-equilibrate the column between gradient runs, thereby reducing the total time for each analysis. The total analysis time for each gradient elution run is only 2.8 minutes, including 0.3 minutes for column reequilibration between analyses. Retention times standard calibration solutes are reproducible to better than 0.002 minutes in consecutive runs. A corrected retention index was adopted to account for day-to-day and column-to-column variations in retention time. The discriminating power and mean list length were calculated for a library of 47 intoxicants and compared with previous work from other laboratories to evaluate fast gradient elution HPLC as a screening tool.

  1. Strategic Combination of Isocratic and Gradient Elution for Simultaneous Separation of Polar Compounds in Traditional Chinese Medicines by HPLC

    Directory of Open Access Journals (Sweden)

    Mei-Tuo Zhang

    2018-01-01

    Full Text Available A simple high-performance liquid chromatography (HPLC method for the simultaneous separation of the highly polar and weakly polar components of traditional Chinese medicines was developed via a strategic combination of isocratic and gradient elution methods. Liu-Shen-Wan and Liu-Wei-Di-Huang-Wan were used as representative examples of traditional Chinese medicines. This is the first time that 6 components of varying degrees of polarity in Liu-Shen-Wan had been successfully resolved in a single chromatographic run using an ultraviolet-visible detector with a fixed wavelength of 296 nm. In contrast to conventional gradient separation methods, this novel method offered a viable route for separation of the highly and weakly polar fractions simultaneously, thus greatly reducing the time and cost of analysis. This method therefore provides a more efficient way to determine the polar components present in traditional Chinese medicines. It would find potential application in drug screening, drug authentication, and product quality control.

  2. Mode I and mixed mode crack-tip fields in strain gradient plasticity

    DEFF Research Database (Denmark)

    Goutianos, Stergios

    2011-01-01

    Strain gradients develop near the crack-tip of Mode I or mixed mode cracks. A finite strain version of the phenomenological strain gradient plasticity theory of Fleck–Hutchinson (2001) is used here to quantify the effect of the material length scales on the crack-tip stress field for a sharp...... stationary crack under Mode I and mixed mode loading. It is found that for material length scales much smaller than the scale of the deformation gradients, the predictions converge to conventional elastic–plastic solutions. For length scales sufficiently large, the predictions converge to elastic solutions....... Thus, the range of length scales over which a strain gradient plasticity model is necessary is identified. The role of each of the three material length scales, incorporated in the multiple length scale theory, in altering the near-tip stress field is systematically studied in order to quantify...

  3. study on 113 Sn-113m In generator of the chromatographic column elution mode

    International Nuclear Information System (INIS)

    Abdel-Halim, A.A.

    2002-01-01

    this work has been carried out to study the optimum conditions required for local preparation of 113 Sn- 113m In radioisotope generator based on 12- molybdocerate- 113 Sn column matrix. this work was directed to: 1- investigate the optimum conditions of the tin target irradiation and dissolution processes. 2- study the different preparative conditions which affect the loading of 113 Sn radionuclide onto 12- molybdocerate (IV) columns and the elution of the generated 113m In radionuclide. 3- study the effect of generator life- time on the elution performance and quality control of the generated 113m In radionuclide over a period of 190 days

  4. Ion temperature gradient modes in toroidal helical systems

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, T. [Graduate University for Advanced Studies, Toki, Gifu (Japan); Sugama, H.; Kanno, R.; Okamoto, M.

    2000-04-01

    Linear properties of ion temperature gradient (ITG) modes in helical systems are studied. The real frequency, growth rate, and eigenfunction are obtained for both stable and unstable cases by solving a kinetic integral equation with proper analytic continuation performed in the complex frequency plane. Based on the model magnetic configuration for toroidal helical systems like the Large Helical Device (LHD), dependences of the ITG mode properties on various plasma equilibrium parameters are investigated. Particularly, relative effects of {nabla}B-curvature drifts driven by the toroidicity and by the helical ripples are examined in order to compare the ITG modes in helical systems with those in tokamaks. (author)

  5. Ion temperature gradient modes in toroidal helical systems

    International Nuclear Information System (INIS)

    Kuroda, T.; Sugama, H.; Kanno, R.; Okamoto, M.

    2000-04-01

    Linear properties of ion temperature gradient (ITG) modes in helical systems are studied. The real frequency, growth rate, and eigenfunction are obtained for both stable and unstable cases by solving a kinetic integral equation with proper analytic continuation performed in the complex frequency plane. Based on the model magnetic configuration for toroidal helical systems like the Large Helical Device (LHD), dependences of the ITG mode properties on various plasma equilibrium parameters are investigated. Particularly, relative effects of ∇B-curvature drifts driven by the toroidicity and by the helical ripples are examined in order to compare the ITG modes in helical systems with those in tokamaks. (author)

  6. Dual-mode gradient HPLC procedure for the simultaneous determination of chloroquine and proguanil.

    Science.gov (United States)

    Paci, A; Caire-Maurisier, A-M; Rieutord, A; Brion, F; Clair, P

    2002-01-01

    In order to assay the antipaludic capsule of the Service de Santé des Armées (SSA), that contains two antimalarial drugs, i.e. chloroquine sulfate (CQS, cp1) and proguanil hydrochloride (PGH, cp5), a HPLC procedure was developed. A reversed-phase ion-pair high-performance liquid chromatography (HPLC) method with an ultraviolet detection at 254 nm was set up and validated. Elution system includes programming of both organic concentration and flow-rate known as 'dual-mode gradient'. This method allows the simultaneous determination of both active compounds and separation of four process related substances. The method is simple, rapid, selective and accurate, and the precision is good with an inter- and intra-assay of <2%. The sensitivity is particularly suitable for pharmaceutical quality control.

  7. Ion temperature gradient mode driven solitons and shocks

    Science.gov (United States)

    Zakir, U.; Adnan, Muhammad; Haque, Q.; Qamar, Anisa; Mirza, Arshad M.

    2016-04-01

    Ion temperature gradient (ITG) driven solitons and shocks are studied in a plasma having gradients in the equilibrium number density and equilibrium ion temperature. In the linear regime, it is found that the ion temperature and the ratio of the gradient scale lengths, ηi=Ln/LT , affect both the real frequency and the growth rate of the ITG driven wave instability. In the nonlinear regime, for the first time we derive a Korteweg de Vries-type equation for the ITG mode, which admits solitary wave solution. It is found that the ITG mode supports only compressive solitons. Further, it is noticed that the soliton amplitude and width are sensitive to the parameter ηi=Ln/LT . Second, in the presence of dissipation in the system, we obtain a Burger type equation, which admits the shock wave solution. This work may be useful to understand the low frequency electrostatic modes in inhomogeneous electron-ion plasma having density and ion temperature gradients. For illustration, the model has been applied to tokamak plasma.

  8. Description of the Retention and Peak Profile for Chromolith Columns in Isocratic and Gradient Elution Using Mobile Phase Composition and Flow Rate as Factors

    Directory of Open Access Journals (Sweden)

    Elsa Cabo-Calvet

    2014-11-01

    Full Text Available The effect of the modifier concentration and flow rate on the chromatographic performance of a second generation Chromolith® RP-18e column, under isocratic and gradient elution with acetonitrile-water mixtures, was examined using four sulphonamides as probe compounds. The acetonitrile concentration was varied between 5 and 55% (v/v, and the flow rate between 0.1 and 5.0 mL/min, keeping the other factors constant. The changes in both retention and peak profile were modelled, and used to build simple plots, where the logarithm of the retention factor was represented against the modifier concentration (in gradient elution, against the initial modifier concentration, and the half-widths or widths against the retention time (in gradient elution, against the time at the column outlet. A particular plot was needed for describing the retention of each sulphonamide, but due to the similar interaction kinetics, a unique plot described the changes in the half-widths for all four sulphonamides. The changes in retention with the flow showed that allegedly in the second generation Chromolith, the column deformation observed for the first generation Chromolith, with the applied pressure at increasing flow, is decreased.

  9. Separation of five compounds from leaves of Andrographis paniculata (Burm. f.) Nees by off-line two-dimensional high-speed counter-current chromatography combined with gradient and recycling elution.

    Science.gov (United States)

    Zhang, Li; Liu, Qi; Yu, Jingang; Zeng, Hualiang; Jiang, Shujing; Chen, Xiaoqing

    2015-05-01

    An off-line two-dimensional high-speed counter-current chromatography method combined with gradient and recycling elution mode was established to isolate terpenoids and flavones from the leaves of Andrographis paniculata (Burm. f.) Nees. By using the solvent systems composed of n-hexane/ethyl acetate/methanol/water with different volume ratios, five compounds including roseooside, 5,4'-dihydroxyflavonoid-7-O-β-d-pyranglucuronatebutylester, 7,8-dimethoxy-2'-hydroxy-5-O-β-d-glucopyranosyloxyflavon, 14-deoxyandrographiside, and andrographolide were successfully isolated. Purities of these isolated compounds were all over 95% as determined by high-performance liquid chromatography. Their structures were identified by UV, mass spectrometry, and (1) H NMR spectroscopy. It has been demonstrated that the combination of off-line two-dimensional high-speed counter-current chromatography with different elution modes is an efficient technique to isolate compounds from complex natural product extracts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Retention prediction of highly polar ionizable solutes under gradient conditions on a mixed-mode reversed-phase and weak anion-exchange stationary phase.

    Science.gov (United States)

    Balkatzopoulou, P; Fasoula, S; Gika, H; Nikitas, P; Pappa-Louisi, A

    2015-05-29

    In the present work the retention of three highly polar and ionizable solutes - uric acid, nicotinic acid and ascorbic acid - was investigated on a mixed-mode reversed-phase and weak anion-exchange (RP/WAX) stationary phase in buffered aqueous acetonitrile (ACN) mobile phases. A U-shaped retention behavior was observed for all solutes with respect to the eluent organic modifier content studied in a range of 5-95% (v/v). This retention behavior clearly demonstrates the presence of a HILIC-type retention mechanism at ACN-rich hydro-organic eluents and an RP-like retention at aqueous-rich hydro-organic eluents. Hence, this column should be promising for application under both RP and HILIC gradient elution modes. For this reason, a series of programmed elution runs were carried out with increasing (RP) and decreasing (HILIC) organic solvent concentration in the mobile phase. This dual gradient process was successfully modeled by two retention models exhibiting a quadratic or a cubic dependence of the logarithm of the solute retention factor (lnk) upon the organic modifier volume fraction (φ). It was found that both models produced by gradient retention data allow the prediction of solute retention times for both types of programmed elution on the mixed-mode column. Four, in the case of the quadratic model, or five, in the case of the cubic model, initial HILIC- and RP-type gradient runs gave satisfactory retention predictions of any similar kind elution program, even with different flow rate, with an overall error of only 2.5 or 1.7%, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Constant pressure mode extended simple gradient liquid chromatography system for micro and nanocolumns

    Czech Academy of Sciences Publication Activity Database

    Šesták, Jozef; Kahle, Vladislav

    2014-01-01

    Roč. 1350, Jul (2014), s. 68-71 ISSN 0021-9673 R&D Projects: GA MV VG20102015023 Institutional support: RVO:68081715 Keywords : constant pressure HPLC * gradient elution * simple liquid chromatograph Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.169, year: 2014 http://hdl.handle.net/11104/0233990

  12. Application of quality by design concept to develop a dual gradient elution stability-indicating method for cloxacillin forced degradation studies using combined mixture-process variable models.

    Science.gov (United States)

    Zhang, Xia; Hu, Changqin

    2017-09-08

    Penicillins are typical of complex ionic samples which likely contain large number of degradation-related impurities (DRIs) with different polarities and charge properties. It is often a challenge to develop selective and robust high performance liquid chromatography (HPLC) methods for the efficient separation of all DRIs. In this study, an analytical quality by design (AQbD) approach was proposed for stability-indicating method development of cloxacillin. The structures, retention and UV characteristics rules of penicillins and their impurities were summarized and served as useful prior knowledge. Through quality risk assessment and screen design, 3 critical process parameters (CPPs) were defined, including 2 mixture variables (MVs) and 1 process variable (PV). A combined mixture-process variable (MPV) design was conducted to evaluate the 3 CPPs simultaneously and a response surface methodology (RSM) was used to achieve the optimal experiment parameters. A dual gradient elution was performed to change buffer pH, mobile-phase type and strength simultaneously. The design spaces (DSs) was evaluated using Monte Carlo simulation to give their possibility of meeting the specifications of CQAs. A Plackett-Burman design was performed to test the robustness around the working points and to decide the normal operating ranges (NORs). Finally, validation was performed following International Conference on Harmonisation (ICH) guidelines. To our knowledge, this is the first study of using MPV design and dual gradient elution to develop HPLC methods and improve separations for complex ionic samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Characterizing the selectivity of stationary phases and organic modifiers in reversed-phase high-performance liquid chromatographic systems by a general solvation equation using gradient elution.

    Science.gov (United States)

    Du, C M; Valko, K; Bevan, C; Reynolds, D; Abraham, M H

    2000-11-01

    Retention data for a set of 69 compounds using rapid gradient elution are obtained on a wide range of reversed-phase stationary phases and organic modifiers. The chromatographic stationary phases studied are Inertsil (IN)-ODS, pentafluorophenyl, fluoro-octyl, n-propylcyano, Polymer (PLRP-S 100), and hexylphenyl. The organic solvent modifiers are 2,2,2-trifluoroethanol (TFE); 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP); isopropanol; methanol (MeOH); acetonitrile (AcN); tetrahydrofuran; 1,4-dioxane; N,N-dimethylformamide; and mixed solvents of dimethylsulfoxide (DMSO) with AcN and DMSO with MeOH (1:1). A total of 25 chromatographic systems are analyzed using a solvation equation. In general, most of the systems give reasonable statistics. The selectivity of the reversed phase-high-performance liquid chromatographic (HPLC) systems with respect to the solute's dipolarity-polarity, hydrogen-bond acidity, and basicity are reflected in correspondingly large coefficients in the solvation equation. We wanted to find the most orthogonal HPLC systems, showing the highest possible selectivity difference in order to derive molecular descriptors using the gradient retention times of a compound. We selected eight chromatographic systems that have a large range of coefficients of interest (s, a, and b) similar to those found in water-solvent partitions used previously to derive molecular descriptors. The systems selected are IN-ODS phases with AcN, MeOH, TFE, and HFIP as mobile phase, PLRP-S 100 phase with AcN, propylcyano phase with AcN and MeOH, and fluorooctyl phase with TFE. Using the retention data obtained for a compound in the selected chromatographic systems, we can estimate the molecular descriptors with the faster and simpler gradient elution method.

  14. Transport through dissipative trapped electron mode and toroidal ion temperature gradient mode in TEXTOR

    International Nuclear Information System (INIS)

    Rogister, A.; Hasselberg, G.; Waelbroeck, F.; Weiland, J.

    1987-12-01

    A self-consistent transport code is used to evaluate how plasma confinement in tokamaks is influenced by the microturbulent fields which are excited by the dissipative trapped electron (DTE) instability. As shown previously, the saturation theory on which the code is based has been developed from first principles. The toroidal coupling resulting from the ion magnetic drifts is neglected; arguments are presented to justify this approximation. The numerical results reproduce well the neo-Alcator scaling law observed experimentally - e.g. in TEXTOR - in non detached ohmic discharges, the confinement degradation which results when auxiliary heating is applied, as well as a large number of other experimental observations. We also assess the possible impact of the toroidal ion temperature gradient mode on energy confinement by estimating the ion thermal flux with the help of the mixing length approximation. (orig./GG)

  15. Unified theory of ballooning instabilities and temperature gradient driven trapped ion modes

    International Nuclear Information System (INIS)

    Xu, X.Q.

    1990-08-01

    A unified theory of temperature gradient driven trapped ion modes and ballooning instabilities is developed using kinetic theory in banana regimes. All known results, such as electrostatic and purely magnetic trapped particle modes and ideal MHD ballooning modes (or shear Alfven waves) are readily derived from our single general dispersion relation. Several new results from ion-ion collision and trapped particle modification of ballooning modes are derived and discussed and the interrelationship between those modes is established. 24 refs

  16. Detachable strong cation exchange monolith, integrated with capillary zone electrophoresis and coupled with pH gradient elution, produces improved sensitivity and numbers of peptide identifications during bottom-up analysis of complex proteomes.

    Science.gov (United States)

    Zhang, Zhenbin; Yan, Xiaojing; Sun, Liangliang; Zhu, Guijie; Dovichi, Norman J

    2015-04-21

    A detachable sulfonate-silica hybrid strong cation-exchange monolith was synthesized in a fused silica capillary, and used for solid phase extraction with online pH gradient elution during capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) proteomic analysis. Tryptic digests were prepared in 50 mM formic acid and loaded onto the strong cation-exchange monolith. Fractions were eluted using a series of buffers with lower concentration but higher pH values than the 50 mM formic acid background electrolyte. This combination of elution and background electrolytes results in both sample stacking and formation of a dynamic pH junction and allows use of relatively large elution buffer volumes while maintaining reasonable peak efficiency and resolution. A series of five pH bumps were applied to elute E. coli tryptic peptides from the monolith, followed by analysis using CZE coupled to an LTQ-Orbitrap Velos mass spectrometer; 799 protein groups and 3381 peptides were identified from 50 ng of the digest in a 2.5 h analysis, which approaches the identification rate for this organism that was obtained with an Orbitrap Fusion. We attribute the improved numbers of peptide and protein identifications to the efficient fractionation by the online pH gradient elution, which decreased the complexity of the sample in each elution step and improved the signal intensity of low abundance peptides. We also performed a comparative analysis using a nanoACQUITY UltraPerformance LCH system. Similar numbers of protein and peptide identifications were produced by the two methods. Protein identifications showed significant overlap between the two methods, whereas peptide identifications were complementary.

  17. Ion-temperature-gradient-driven modes in bi-ion magnetoplasma

    Energy Technology Data Exchange (ETDEWEB)

    Batool, Nazia; Mirza, Arshad M [Theoretical Plasma Physics Group, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Qamar, Anisa [Department of Physics, Peshawar University, NWFP 25120 (Pakistan)], E-mail: nazia.batool@ncp.edu.pk

    2008-12-15

    The toroidal ion-temperature-gradient (ITG)-driven electrostatic drift waves are investigated for bi-ion plasmas with equilibrium density, temperature and magnetic field gradients. Using Braginskii's transport equations for the ions and Boltzmann distributed electrons, the mode coupling equations are derived. New ITG-driven modes are shown to exist. The results of the present study should be helpful to understand several wave phenomena in space and tokamak plasmas.

  18. Rapid Determination of Amino Acids in Beer, Red Wine, and Donkey-Hide Gelatin by Gradient Elution of HPLC: From Micellar Liquid Chromatography to High Submicellar Liquid Chromatography.

    Science.gov (United States)

    Xie, Yunfei; Luo, Tian; Yang, Jing; Dong, Yuming

    2018-01-01

    Amino acids (AAs) in beer, red wine, and donkey-hide gelatin were rapidly determined by gradient LC elution from micellar LC to high submicellar LC. Mobile phase A was a 0.075 M sodium dodecyl sulfate solution containing 20 mM ammonium acetate with a pH value adjusted to 3.5 with acetic acid solution, and mobile phase B was acetonitrile. Optimized chromatographic conditions were as follows: mobile phase B increased from 25 to 60% (v/v) in 30 min and the use of a Venusil XBP C18 column (5 µm, 250 × 4.6 mm) as the stationary phase, with a column temperature of 35°C, flow rate of 1.2 mL/min, and detection wavelength of 266 nm. The results indicated good linearity (r2 ≥ 0.9924). The intraday precision of the retention time was RSD ≤ 1.1%, whereas interday was RSD ≤ 3.2%; intraday precision of the peak area was RSD ≤ 3.3%, whereas interday was RSD ≤ 4.9%. The range of recovery was 94.6-102.4%. The RSDs of the retention time for the AAs for the different samples were 0.04-0.31%.

  19. Preparative Separation of Sulfur-Containing Diketopiperazines from Marine Fungus Cladosporium sp. Using High-Speed Counter-Current Chromatography in Stepwise Elution Mode

    OpenAIRE

    Gu, Binbin; Zhang, Yanying; Ding, Lijian; He, Shan; Wu, Bin; Dong, Junde; Zhu, Peng; Chen, Juanjuan; Zhang, Jinrong; Yan, Xiaojun

    2015-01-01

    High-speed counter-current chromatography (HSCCC) was successively applied to the separation of three sulfur-containing diketopiperazines (DKPs) (including two new compounds cladosporin A (1) and cladosporin B (3), and a known compound haematocin (2)) from a marine fungus Cladosporium sp. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at (1:1:1:1, v/v) and (2:1:2:1, v/v), in stepwise elution mode, was used for HSCCC. The preparative HSCCC separation was perfor...

  20. Effects of the safety factor on ion temperature gradient modes

    International Nuclear Information System (INIS)

    Wang, A.K.; Dong, J.Q.; Sanuki, H.; Itoh, K.

    2003-01-01

    A model for the ion temperature gradient (ITG) driven instability is derived from Braginskii magnetohydrodynamic equations of ions. The safety factor q in a toroidal plasma is introduced into the model through the current density J parallel . The effects of q or J parallel on both the ITG instability in k perpendicular and k parallel spectra and the critical stability thresholds are studied. It is shown that the current density // J or the safety factor q plays an important role in stabilizing the ITG instability. (author)

  1. Conjugate gradient filtering of instantaneous normal modes, saddles on the energy landscape, and diffusion in liquids.

    Science.gov (United States)

    Chowdhary, J; Keyes, T

    2002-02-01

    Instantaneous normal modes (INM's) are calculated during a conjugate-gradient (CG) descent of the potential energy landscape, starting from an equilibrium configuration of a liquid or crystal. A small number (approximately equal to 4) of CG steps removes all the Im-omega modes in the crystal and leaves the liquid with diffusive Im-omega which accurately represent the self-diffusion constant D. Conjugate gradient filtering appears to be a promising method, applicable to any system, of obtaining diffusive modes and facilitating INM theory of D. The relation of the CG-step dependent INM quantities to the landscape and its saddles is discussed.

  2. Plasma-edge gradients in L-mode and ELM-free H-mode JET plasmas

    International Nuclear Information System (INIS)

    Breger, P.; Zastrow, K.-D.; Davies, S.J.; K ig, R.W.T.; Summers, D.D.R.; Hellermann, M.G. von; Flewin, C.; Hawkes, N.C.; Pietrzyk, Z.A.; Porte, L.

    1998-01-01

    Experimental plasma-edge gradients in JET during the edge-localized-mode (ELM) free H-mode are examined for evidence of the presence and location of the transport barrier region inside the magnetic separatrix. High spatial resolution data in electron density is available in- and outside the separatrix from an Li-beam diagnostic, and in electron temperature inside the separatrix from an ECE diagnostic, while outside the separatrix, a reciprocating probe provides electron density and temperature data in the scrape-off layer. Ion temperatures and densities are measured using an edge charge-exchange diagnostic. A comparison of observed widths and gradients of this edge region with each other and with theoretical expectations is made. Measurements show that ions and electrons form different barrier regions. Furthermore, the electron temperature barrier width (3-4 cm) is about twice that of electron density, in conflict with existing scaling laws. Suitable parametrization of the edge data enables an electron pressure gradient to be deduced for the first time at JET. It rises during the ELM-free phase to reach only about half the marginal pressure gradient expected from ballooning stability before the first ELM. Subsequent type I ELMs occur on a pressure gradient contour roughly consistent with both a constant barrier width model and a ballooning mode envelope model. (author)

  3. Role of Density Gradient Driven Trapped Electron Modes in the H-Mode Inner Core with Electron Heating

    Science.gov (United States)

    Ernst, D.

    2015-11-01

    We present new experiments and nonlinear gyrokinetic simulations showing that density gradient driven TEM (DGTEM) turbulence dominates the inner core of H-Mode plasmas during strong electron heating. Thus α-heating may degrade inner core confinement in H-Mode plasmas with moderate density peaking. These DIII-D low torque quiescent H-mode experiments were designed to study DGTEM turbulence. Gyrokinetic simulations using GYRO (and GENE) closely match not only particle, energy, and momentum fluxes, but also density fluctuation spectra, with and without ECH. Adding 3.4 MW ECH doubles Te /Ti from 0.5 to 1.0, which halves the linear TEM critical density gradient, locally flattening the density profile. Density fluctuations from Doppler backscattering (DBS) intensify near ρ = 0.3 during ECH, displaying a band of coherent fluctuations with adjacent toroidal mode numbers. GYRO closely reproduces the DBS spectrum and its change in shape and intensity with ECH, identifying these as coherent TEMs. Prior to ECH, parallel flow shear lowers the effective nonlinear DGTEM critical density gradient 50%, but is negligible during ECH, when transport displays extreme stiffness in the density gradient. GS2 predictions show the DGTEM can be suppressed, to avoid degradation with electron heating, by broadening the current density profile to attain q0 >qmin > 1 . A related experiment in the same regime varied the electron temperature gradient in the outer half-radius (ρ ~ 0 . 65) using ECH, revealing spatially coherent 2D mode structures in the Te fluctuations measured by ECE imaging. Fourier analysis with modulated ECH finds a threshold in Te profile stiffness. Supported by the US DOE under DE-FC02-08ER54966 and DE-FC02-04ER54698.

  4. Purification of camel liver catalase by zinc chelate affinity chromatography and pH gradient elution: An enzyme with interesting properties.

    Science.gov (United States)

    Chafik, Abdelbasset; Essamadi, Abdelkhalid; Çelik, Safinur Yildirim; Mavi, Ahmet

    2017-12-01

    Climate change and increasing temperatures are global concerns. Camel (Camelus dromedarius) lives most of its life under high environmental stress in the desert and represent ideal model for studying desert adaptation among mammals. Catalase plays a key role in protecting cells against oxidative stress. For the first time, catalase from camel liver was purified to homogeneity by zinc chelate affinity chromatography using pH gradient elution, a better separation was obtained. A purification fold of 201.81 with 1.17% yield and a high specific activity of 1132539.37U/mg were obtained. The native enzyme had a molecular weight of 268kDa and was composed of four subunits of equal size (65kDa). The enzyme showed optimal activity at a temperature of 45°C and pH 7.2. Thiol reagents, β-Mercaptoethanol and D,L-Dithiothreitol, inhibited the enzyme activity. The enzyme was inhibited by Al 3+ , Cd 2+ and Mg 2+ , whereas Ca 2+ , Co 2+ and Ni 2+ stimulated the catalase activity. Reduced glutathione has no effect on catalase activity. The K m and V max of the enzyme for hydrogen peroxide were 37.31mM and 6185157U/mg, respectively. Sodium azide inhibited the enzyme noncompetitively with K i value of 14.43μM, the IC 50 was found to be 16.71μM. The properties of camel catalase were different comparing to those of mammalian species. Relatively higher molecular weight, higher optimum temperature, protection of reduced glutathione from hydrogen peroxide oxidation and higher affinity for hydrogen peroxide and sodium azide, these could be explained by the fact that camel is able to live in the intense environmental stress in the desert. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. High gradient test of the C-band choke-mode type accelerating structure

    International Nuclear Information System (INIS)

    Inagaki, T.; Shintake, T.; Baba, H.; Togawa, K.; Onoe, K.; Marechal, X.; Takashima, T.; Takahashi, S.; Matsumoto, H.

    2004-01-01

    The C-band (5712 MHz) choke-mode type accelerating structure will be used for SPring-8 Compact SASE-FEL Source (SCSS). To make the accelerator length short, we designed the field gradient as high as 40 MV/m. Since it is higher gradient than other traditional electron accelerators, we have to carefully check its performance (RF breakdown, dark current emission, etc.) in the high gradient test stand. The first experiment will be scheduled in this summer. In this paper, we will describe the preparation progress for the test. (author)

  6. Ion temperature gradient driven mode in presence of transverse velocity shear in magnetized plasmas

    DEFF Research Database (Denmark)

    Chakrabarti, N.; Juul Rasmussen, J.; Michelsen, Poul

    2005-01-01

    The effect of sheared poloidal flow on the toroidal branch of the ion temperature gradient driven mode of magnetized nonuniform plasma is studied. A novel "nonmodal" calculation is used to analyze the problem. It is shown that the transverse shear flow considerably reduced the growth...

  7. The impact of edge gradients in the pressure, density, ion temperature, and electron temperature on edge-localized modes

    International Nuclear Information System (INIS)

    Kleva, Robert G.; Guzdar, Parvez N.

    2011-01-01

    The magnitude of the energy and particle fluxes in simulations of edge-localized modes (ELMs) is determined by the edge gradients in the pressure, density, ion temperature, and electron temperature. The total edge pressure gradient is the dominant influence on ELMs by far. An increase (decrease) of merely 2% in the pressure gradient results in an increase (decrease) of more than a factor of ten in the size of the ELM bursts. At a fixed pressure gradient, the size of the ELM bursts decreases as the density gradient increases, while the size of the bursts increases as the electron temperature gradient or, especially, the ion temperature gradient increases.

  8. Numerical simulation of ion temperature gradient driven modes in the presence of ion-ion collisions

    International Nuclear Information System (INIS)

    Xu, X.Q.

    1990-08-01

    Ion temperature gradient driven modes in the presence of ion-ion collisions in a toroidal geometry with trapped ions have been studied by using a 1 2/2 d linearized gyro-kinetic particle simulation code in the electrostatic limit. The purpose of the investigation is to try to understand the physics of flat density discharges, in order to test the marginal stability hypothesis. Results giving threshold conditions of L Ti /R 0 , an upper bound on k χ , and linear growth rates and mode frequencies over all wavelengths for the collisionless ion temperature gradient driven modes are obtained. The behavior of ion temperature gradient driven instabilities in the transition from slab to toroidal geometry, with trapped ions, is shown. A Monte Carlo scheme for the inclusion of ion-ion collisions, in which ions can undergo Coulomb collisional dynamical friction, velocity space diffusion and random walk of guiding centers, has been constructed. The effects of ion-ion collisions on the long wave length limit of the ion modes is discussed. 44 refs., 12 figs

  9. Properties of ion temperature gradient and trapped electron modes in tokamak plasmas with inverted density profiles

    Science.gov (United States)

    Du, Huarong; Jhang, Hogun; Hahm, T. S.; Dong, J. Q.; Wang, Z. X.

    2017-12-01

    We perform a numerical study of linear stability of the ion temperature gradient (ITG) mode and the trapped electron mode (TEM) in tokamak plasmas with inverted density profiles. A local gyrokinetic integral equation is applied for this study. From comprehensive parametric scans, we obtain stability diagrams for ITG modes and TEMs in terms of density and temperature gradient scale lengths. The results show that, for the inverted density profile, there exists a normalized threshold temperature gradient above which the ITG mode and the TEM are either separately or simultaneously unstable. The instability threshold of the TEM for the inverted density profile is substantially different from that for normal and flat density profiles. In addition, deviations are found on the ITG threshold from an early analytic theory in sheared slab geometry with the adiabatic electron response [T. S. Hahm and W. M. Tang, Phys. Fluids B 1, 1185 (1989)]. A possible implication of this work on particle transport in pellet fueled tokamak plasmas is discussed.

  10. Linear and nonlinear dynamics of electron temperature gradient mode in non-Maxwellian plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Zakir, U.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar (Pakistan); Haque, Q. [Theoretical Plasma Physics Division, PINSTECH, Islamabad (Pakistan); National Centre for Physics, Islamabad (Pakistan)

    2013-05-15

    The effect of non-Maxwellian distributed ions on electron temperature gradient mode is investigated. The linear dispersion relation of η{sub e}−mode is obtained which shows that the behavior of this mode changes in the presence of superthermal ions. The growth rate of η{sub e}−mode driven linear instability is found and is observed to modify due to nonthermal ions. However, it is found that this leaves the electron energy transport coefficient unchanged. In the nonlinear regime, a dipolar vortex solution is derived which indicates that the dynamic behavior of the vortices changes with the inclusion of kappa distributed ions. The importance of present study with respect to space and laboratory plasmas is also pointed out.

  11. Regulation of electron temperature gradient turbulence by zonal flows driven by trapped electron modes

    Science.gov (United States)

    Asahi, Y.; Ishizawa, A.; Watanabe, T.-H.; Tsutsui, H.; Tsuji-Iio, S.

    2014-05-01

    Turbulent transport caused by electron temperature gradient (ETG) modes was investigated by means of gyrokinetic simulations. It was found that the ETG turbulence can be regulated by meso-scale zonal flows driven by trapped electron modes (TEMs), which are excited with much smaller growth rates than those of ETG modes. The zonal flows of which radial wavelengths are in between the ion and the electron banana widths are not shielded by trapped ions nor electrons, and hence they are effectively driven by the TEMs. It was also shown that an E × B shearing rate of the TEM-driven zonal flows is larger than or comparable to the growth rates of long-wavelength ETG modes and TEMs, which make a main contribution to the turbulent transport before excitation of the zonal flows.

  12. Nonlinear theory of trapped electron temperature gradient driven turbulence in flat density H-mode plasmas

    International Nuclear Information System (INIS)

    Hahm, T.S.

    1990-12-01

    Ion temperature gradient turbulence based transport models have difficulties reconciling the recent DIII-D H-mode results where the density profile is flat, but χ e > χ i in the core region. In this work, a nonlinear theory is developed for recently discovered ion temperature gradient trapped electron modes propagating in the electron diamagnetic direction. This instability is predicted to be linearly unstable for L Ti /R approx-lt κ θ ρ s approx-lt (L Ti /R) 1/4 . They are also found to be strongly dispersive even at these long wavelengths, thereby suggesting the importance of the wave-particle-wave interactions in the nonlinear saturation phase. The fluctuation spectrum and anomalous fluxes are calculated. In accordance with the trends observed in DIII-D, the predicted electron thermal diffusivity can be larger than the ion thermal diffusivity. 17 refs., 3 figs

  13. Comparisons of theoretically predicted transport from ion temperature gradient instabilities to L-mode tokamak experiments

    International Nuclear Information System (INIS)

    Kotschenreuther, M.; Wong, H.V.; Lyster, P.L.; Berk, H.L.; Denton, R.; Miner, W.H.; Valanju, P.

    1991-12-01

    The theoretical transport from kinetic micro-instabilities driven by ion temperature gradients is a sheared slab is compared to experimentally inferred transport in L-mode tokamaks. Low noise gyrokinetic simulation techniques are used to obtain the ion thermal transport coefficient X. This X is much smaller than in experiments, and so cannot explain L-mode confinement. Previous predictions based on fluid models gave much greater X than experiments. Linear and nonlinear comparisons with the fluid model show that it greatly overestimates transport for experimental parameters. In addition, disagreements among previous analytic and simulation calculations of X in the fluid model are reconciled

  14. Chaos in toroidal ion-temperature-gradient-driven modes in dust-contaminated magnetoplasma

    Energy Technology Data Exchange (ETDEWEB)

    Qamar, Anisa; Atta-Ullah-Shah [Theoretical Plasma Physics Group, Institute of Physics and Electronics, University of Peshawar Khyber Pakhtunkhwa 25000 (Pakistan); Yaqub Khan, M; Ayub, M [Department of Mathematics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Mirza, Arshad M, E-mail: anisaqamar@gmail.com [Theoretical Plasma Physics Group, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2011-06-01

    A new set of nonlinear equations for toroidal ion-temperature-gradient-driven (ITGD) drift-dissipative waves is derived by using Braginskii's transport model of the ion dynamics and the Boltzmann distribution of electrons in the presence of negatively charged dust grains. The temporal behaviour of the nonlinear ITGD mode is found to be governed by three nonlinear equations for the amplitudes, which is a generalization of Lorenz- and Stenflo-type equations admitting chaotic trajectories. The linear stability analysis has been presented and stationary points for our generalized mode coupling equations are also derived.

  15. Modeling and simulation of protein elution in linear pH and salt gradients on weak, strong and mixed cation exchange resins applying an extended Donnan ion exchange model.

    Science.gov (United States)

    Wittkopp, Felix; Peeck, Lars; Hafner, Mathias; Frech, Christian

    2018-04-13

    Process development and characterization based on mathematic modeling provides several advantages and has been applied more frequently over the last few years. In this work, a Donnan equilibrium ion exchange (DIX) model is applied for modelling and simulation of ion exchange chromatography of a monoclonal antibody in linear chromatography. Four different cation exchange resin prototypes consisting of weak, strong and mixed ligands are characterized using pH and salt gradient elution experiments applying the extended DIX model. The modelling results are compared with the results using a classic stoichiometric displacement model. The Donnan equilibrium model is able to describe all four prototype resins while the stoichiometric displacement model fails for the weak and mixed weak/strong ligands. Finally, in silico chromatogram simulations of pH and pH/salt dual gradients are performed to verify the results and to show the consistency of the developed model. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Preparative separation of sulfur-containing diketopiperazines from marine fungus Cladosporium sp. using high-speed counter-current chromatography in stepwise elution mode.

    Science.gov (United States)

    Gu, Binbin; Zhang, Yanying; Ding, Lijian; He, Shan; Wu, Bin; Dong, Junde; Zhu, Peng; Chen, Juanjuan; Zhang, Jinrong; Yan, Xiaojun

    2015-01-09

    High-speed counter-current chromatography (HSCCC) was successively applied to the separation of three sulfur-containing diketopiperazines (DKPs) (including two new compounds cladosporin A (1) and cladosporin B (3), and a known compound haematocin (2)) from a marine fungus Cladosporium sp. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at (1:1:1:1, v/v) and (2:1:2:1, v/v), in stepwise elution mode, was used for HSCCC. The preparative HSCCC separation was performed on 300 mg of crude sample yielding 26.7 mg of compound 3 at a purity of over 95%, 53.6 mg of a mixture of compounds 1 and 2, which was further separated by preparative-HPLC yielding 14.3 mg of compound 1 and 25.4 mg of compound 2 each at a purity of over 95%. Their structures were established by spectroscopic methods. The sulfur-containing DKPs suppressed the proliferation of hepatocellular carcinoma cell line HepG2. The present work represents the first application of HSCCC in the efficient preparation of marine fungal natural products.

  17. Preparative Separation of Sulfur-Containing Diketopiperazines from Marine Fungus Cladosporium sp. Using High-Speed Counter-Current Chromatography in Stepwise Elution Mode

    Directory of Open Access Journals (Sweden)

    Binbin Gu

    2015-01-01

    Full Text Available High-speed counter-current chromatography (HSCCC was successively applied to the separation of three sulfur-containing diketopiperazines (DKPs (including two new compounds cladosporin A (1 and cladosporin B (3, and a known compound haematocin (2 from a marine fungus Cladosporium sp. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water at (1:1:1:1, v/v and (2:1:2:1, v/v, in stepwise elution mode, was used for HSCCC. The preparative HSCCC separation was performed on 300 mg of crude sample yielding 26.7 mg of compound 3 at a purity of over 95%, 53.6 mg of a mixture of compounds 1 and 2, which was further separated by preparative-HPLC yielding 14.3 mg of compound 1 and 25.4 mg of compound 2 each at a purity of over 95%. Their structures were established by spectroscopic methods. The sulfur-containing DKPs suppressed the proliferation of hepatocellular carcinoma cell line HepG2. The present work represents the first application of HSCCC in the efficient preparation of marine fungal natural products.

  18. Threshold for the destabilisation of the ion-temperature-gradient mode in magnetically confined toroidal plasmas

    Science.gov (United States)

    Zocco, A.; Xanthopoulos, P.; Doerk, H.; Connor, J. W.; Helander, P.

    2018-02-01

    The threshold for the resonant destabilisation of ion-temperature-gradient (ITG) driven instabilities that render the modes ubiquitous in both tokamaks and stellarators is investigated. We discover remarkably similar results for both confinement concepts if care is taken in the analysis of the effect of the global shear . We revisit, analytically and by means of gyrokinetic simulations, accepted tokamak results and discover inadequacies of some aspects of their theoretical interpretation. In particular, for standard tokamak configurations, we find that global shear effects on the critical gradient cannot be attributed to the wave-particle resonance destabilising mechanism of Hahm & Tang (Phys. Plasmas, vol. 1, 1989, pp. 1185-1192), but are consistent with a stabilising contribution predicted by Biglari et al. (Phys. Plasmas, vol. 1, 1989, pp. 109-118). Extensive analytical and numerical investigations show that virtually no previous tokamak theoretical predictions capture the temperature dependence of the mode frequency at marginality, thus leading to incorrect instability thresholds. In the asymptotic limit , where is the rotational transform, and such a threshold should be solely determined by the resonant toroidal branch of the ITG mode, we discover a family of unstable solutions below the previously known threshold of instability. This is true for a tokamak case described by a local local equilibrium, and for the stellarator Wendelstein 7-X, where these unstable solutions are present even for configurations with a small trapped-particle population. We conjecture they are of the Floquet type and derive their properties from the Fourier analysis of toroidal drift modes of Connor & Taylor (Phys. Fluids, vol. 30, 1987, pp. 3180-3185), and to Hill's theory of the motion of the lunar perigee (Acta Math., vol. 8, 1886, pp. 1-36). The temperature dependence of the newly determined threshold is given for both confinement concepts. In the first case, the new temperature-gradient

  19. Stabilization of ion temperature gradient driven modes by lower hybrid wave in a tokamak

    International Nuclear Information System (INIS)

    Kuley, Animesh; Tripathi, V. K.

    2009-01-01

    A gyrokinetic formalism has been developed to study lower hybrid wave stabilization of ion temperature gradient driven modes, responsible for anomalous ion transport in the inner region of tokamak. The parametric coupling between lower hybrid and drift waves produce lower hybrid sideband waves. The pump and the sidebands exert a ponderomotive force on electrons, modifying the eigenfrequency of the drift wave and influencing the growth rate. The longer wavelength drift waves are destabilized by the lower hybrid wave while the shorter wavelengths are suppressed. The requiste lower hybrid power is in the range of ∼900 kW at 4.6 GHz.

  20. Evaluation of electrochemical ion exchange for cesium elution

    International Nuclear Information System (INIS)

    Bontha, J.D.; Kurath, D.E.; Surma, J.E.; Buehler, M.F.

    1996-04-01

    Electrochemical elution was investigated as an alternative method to acid elution for the desorption of cesium from loaded ion exchange resins. The approach was found to have several potential advantages over existing technologies, in particular, electrochemical elution eliminates the need for addition of chemicals to elute cesium from the ion exchange resin. Also, since, in the electrochemical elution process the eluting solution is not in direct contact with the ion exchange material, very small volumes of the eluting solution can be used in a complete recycle mode in order to minimize the total volume of the cesium elute. In addition, the cesium is eluted as an alkaline solution that does not require neutralization with caustic to meet the tank farm specifications. Other advantages include easy incorporation of the electrochemical elution process into the present cesium recovery schemes

  1. Anomalous ion thermal transport in hot ion plasmas by the ion temperature gradient mode

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.Y.; Horton, W. (Texas Univ., Austin, TX (United States). Inst. for Fusion Studies); Coppi, B. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Research Lab. of Electronics)

    1992-01-01

    Experiments show that the observed radial profiles of the ion thermal conductivity {chi}{sub i} have the opposite shapes with those obtained from the ion temperature gradient mode ({eta}{sub i} mode) turbulence model by the traditional mixing length estimate. In this work, this radial profile problem is reconsidered with an electromagnetic study of the linear stability of the toroidal {eta}{sub i} mode and a new rule for choosing the mixing length. It is first shown that the electromagnetic effect gives a significant stabilizing effect on the toroidal {eta}{sub i} mode, and that the observed reduction of {chi}{sub i}(r) in the core region can be explained by this electromagnetic effect. Secondly, in view of earlier numerical simulations showing the transfer of fluctuation energy to larger scales that those for the fastest growth rate, as well as fluctuation measurements indicating longer radial correlation lengths, a new mixing length formula is proposed to explain the radial increase of the {chi}{sub i}. It is shown the new formula fits well the observed {chi}{sub i}(r) profiles in two TFTR supershot discharges and also gives the scaling law in the current and the magnetic field which agrees better with experiment than the conventional formula.

  2. Anomalous ion thermal transport in hot ion plasmas by the ion temperature gradient mode

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.Y.; Horton, W. [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies; Coppi, B. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Research Lab. of Electronics

    1992-08-01

    Experiments show that the observed radial profiles of the ion thermal conductivity {chi}{sub i} have the opposite shapes with those obtained from the ion temperature gradient mode ({eta}{sub i} mode) turbulence model by the traditional mixing length estimate. In this work, this radial profile problem is reconsidered with an electromagnetic study of the linear stability of the toroidal {eta}{sub i} mode and a new rule for choosing the mixing length. It is first shown that the electromagnetic effect gives a significant stabilizing effect on the toroidal {eta}{sub i} mode, and that the observed reduction of {chi}{sub i}(r) in the core region can be explained by this electromagnetic effect. Secondly, in view of earlier numerical simulations showing the transfer of fluctuation energy to larger scales that those for the fastest growth rate, as well as fluctuation measurements indicating longer radial correlation lengths, a new mixing length formula is proposed to explain the radial increase of the {chi}{sub i}. It is shown the new formula fits well the observed {chi}{sub i}(r) profiles in two TFTR supershot discharges and also gives the scaling law in the current and the magnetic field which agrees better with experiment than the conventional formula.

  3. Anomalous ion thermal transport in hot ion plasmas by the ion temperature gradient mode

    International Nuclear Information System (INIS)

    Kim, J.Y.; Horton, W.; Coppi, B.

    1992-01-01

    Experiments show that the observed radial profiles of the ion thermal conductivity χ i have the opposite shapes with those obtained from the ion temperature gradient mode (η i mode) turbulence model by the traditional mixing length estimate. In this work, this radial profile problem is reconsidered with an electromagnetic study of the linear stability of the toroidal η i mode and a new rule for choosing the mixing length. It is first shown that the electromagnetic effect gives a significant stabilizing effect on the toroidal η i mode, and that the observed reduction of χ i (r) in the core region can be explained by this electromagnetic effect. Secondly, in view of earlier numerical simulations showing the transfer of fluctuation energy to larger scales that those for the fastest growth rate, as well as fluctuation measurements indicating longer radial correlation lengths, a new mixing length formula is proposed to explain the radial increase of the χ i . It is shown the new formula fits well the observed χ i (r) profiles in two TFTR supershot discharges and also gives the scaling law in the current and the magnetic field which agrees better with experiment than the conventional formula

  4. Weak turbulence theory of ion temperature gradient modes for inverted density plasmas

    International Nuclear Information System (INIS)

    Hahm, T.S.; Tang, W.M.

    1989-09-01

    Typical profiles measured in H-mode (''high confinement'') discharges from tokamaks such as JET and DIII-D suggest that the ion temperature gradient instability threshold parameter η i (≡dlnT i /dlnn i ) could be negative in many cases. Previous linear theoretical calculations have established the onset conditions for these negative η i -modes and the fact that their growth rate is much smaller than their real frequency over a wide range of negative η i values. This has motivated the present nonlinear weak turbulence analysis to assess the relevance of such instabilities for confinement in H-mode plasmas. The nonlinear eigenmode equation indicates that the 3-wave coupling to shorter wavelength modes is the dominant nonlinear saturation mechanism. It is found that both the saturation level for these fluctuations and the magnitude of the associated ion thermal diffusivity are considerably smaller than the strong turbulence mixing length type estimates for the more conventional positive-η i -instabilities. 19 refs., 3 figs

  5. A study of self organized criticality in ion temperature gradient mode driven gyrokinetic turbulence

    Science.gov (United States)

    Mavridis, M.; Isliker, H.; Vlahos, L.; Görler, T.; Jenko, F.; Told, D.

    2014-10-01

    An investigation on the characteristics of self organized criticality (Soc) in ITG mode driven turbulence is made, with the use of various statistical tools (histograms, power spectra, Hurst exponents estimated with the rescaled range analysis, and the structure function method). For this purpose, local non-linear gyrokinetic simulations of the cyclone base case scenario are performed with the GENE software package. Although most authors concentrate on global simulations, which seem to be a better choice for such an investigation, we use local simulations in an attempt to study the locally underlying mechanisms of Soc. We also study the structural properties of radially extended structures, with several tools (fractal dimension estimate, cluster analysis, and two dimensional autocorrelation function), in order to explore whether they can be characterized as avalanches. We find that, for large enough driving temperature gradients, the local simulations exhibit most of the features of Soc, with the exception of the probability distribution of observables, which show a tail, yet they are not of power-law form. The radial structures have the same radial extent at all temperature gradients examined; radial motion (transport) though appears only at large temperature gradients, in which case the radial structures can be interpreted as avalanches.

  6. A study of self organized criticality in ion temperature gradient mode driven gyrokinetic turbulence

    International Nuclear Information System (INIS)

    Mavridis, M.; Isliker, H.; Vlahos, L.; Görler, T.; Jenko, F.; Told, D.

    2014-01-01

    An investigation on the characteristics of self organized criticality (Soc) in ITG mode driven turbulence is made, with the use of various statistical tools (histograms, power spectra, Hurst exponents estimated with the rescaled range analysis, and the structure function method). For this purpose, local non-linear gyrokinetic simulations of the cyclone base case scenario are performed with the GENE software package. Although most authors concentrate on global simulations, which seem to be a better choice for such an investigation, we use local simulations in an attempt to study the locally underlying mechanisms of Soc. We also study the structural properties of radially extended structures, with several tools (fractal dimension estimate, cluster analysis, and two dimensional autocorrelation function), in order to explore whether they can be characterized as avalanches. We find that, for large enough driving temperature gradients, the local simulations exhibit most of the features of Soc, with the exception of the probability distribution of observables, which show a tail, yet they are not of power-law form. The radial structures have the same radial extent at all temperature gradients examined; radial motion (transport) though appears only at large temperature gradients, in which case the radial structures can be interpreted as avalanches

  7. A study of self organized criticality in ion temperature gradient mode driven gyrokinetic turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Mavridis, M.; Isliker, H.; Vlahos, L. [Section of Astrophysics, Astronomy and Mechanics, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Görler, T.; Jenko, F.; Told, D. [Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching (Germany)

    2014-10-15

    An investigation on the characteristics of self organized criticality (Soc) in ITG mode driven turbulence is made, with the use of various statistical tools (histograms, power spectra, Hurst exponents estimated with the rescaled range analysis, and the structure function method). For this purpose, local non-linear gyrokinetic simulations of the cyclone base case scenario are performed with the GENE software package. Although most authors concentrate on global simulations, which seem to be a better choice for such an investigation, we use local simulations in an attempt to study the locally underlying mechanisms of Soc. We also study the structural properties of radially extended structures, with several tools (fractal dimension estimate, cluster analysis, and two dimensional autocorrelation function), in order to explore whether they can be characterized as avalanches. We find that, for large enough driving temperature gradients, the local simulations exhibit most of the features of Soc, with the exception of the probability distribution of observables, which show a tail, yet they are not of power-law form. The radial structures have the same radial extent at all temperature gradients examined; radial motion (transport) though appears only at large temperature gradients, in which case the radial structures can be interpreted as avalanches.

  8. Electron critical gradient scale length measurements of ICRF heated L-mode plasmas at Alcator C-Mod tokamak

    Science.gov (United States)

    Houshmandyar, S.; Hatch, D. R.; Horton, C. W.; Liao, K. T.; Phillips, P. E.; Rowan, W. L.; Zhao, B.; Cao, N. M.; Ernst, D. R.; Greenwald, M.; Howard, N. T.; Hubbard, A. E.; Hughes, J. W.; Rice, J. E.

    2018-04-01

    A profile for the critical gradient scale length (Lc) has been measured in L-mode discharges at the Alcator C-Mod tokamak, where electrons were heated by an ion cyclotron range of frequency through minority heating with the intention of simultaneously varying the heat flux and changing the local gradient. The electron temperature gradient scale length (LTe-1 = |∇Te|/Te) profile was measured via the BT-jog technique [Houshmandyar et al., Rev. Sci. Instrum. 87, 11E101 (2016)] and it was compared with electron heat flux from power balance (TRANSP) analysis. The Te profiles were found to be very stiff and already above the critical values, however, the stiffness was found to be reduced near the q = 3/2 surface. The measured Lc profile is in agreement with electron temperature gradient (ETG) models which predict the dependence of Lc-1 on local Zeff, Te/Ti, and the ratio of the magnetic shear to the safety factor. The results from linear Gene gyrokinetic simulations suggest ETG to be the dominant mode of turbulence in the electron scale (k⊥ρs > 1), and ion temperature gradient/trapped electron mode modes in the ion scale (k⊥ρs < 1). The measured Lc profile is in agreement with the profile of ETG critical gradients deduced from Gene simulations.

  9. Preparative Separation of Phenolic Compounds from Chimonanthus praecox Flowers by High-Speed Counter-Current Chromatography Using a Stepwise Elution Mode

    Directory of Open Access Journals (Sweden)

    Huaizhi Li

    2016-08-01

    Full Text Available High-speed counter-current chromatography (HSCCC has been successfully used for the separation of eight compounds from Chimonanthus praecox flowers. Firstly, the crude extract of Chimonanthus praecox flowers was dissolved in a two-phase solvent system composed of petroleum ether–ethyl acetate–methanol–H2O (5:5:3:7, v/v and divided into two parts: the upper phase (part I and the lower phase (part II. Then, HSCCC was applied to separate the phenolic acids from part I and part II, respectively. Considering the broad polarity range of target compounds in part I, a stepwise elution mode was established. Two optimal solvent systems of petroleum ether–ethyl acetate–methanol–H2O–formic acid (FA (5:5:3:7:0.02, 5:5:4.3:5.7:0.02, v/v were employed in this separation. Five phenylpropanoids and two flavonoids were successfully separated from 280 mg of part I, including 8.7 mg of 3,4-dihydroxy benzoic acid (a, 95.3% purity, 10.9 mg of protocatechualdehyde (b, 96.8% purity, 11.3 mg of p-coumaric acid (c, 98.9% purity, 12.2 mg of p-hydroxybenzaldehyde (d, 95.9% purity, 24.7 mg of quercetin (e, 97.3% purity, 33.8 mg of kaempferol (f, 96.8% purity, and 24.6 mg of 4-hydroxylcinnamic aldehyde (g, 98.0% purity. From 300 mg of part II, 65.7 mg of rutin (h, 98.2% purity, 7.5 mg of 3,4-dihydroxy benzoic acid (a, 77.4% purity, and 4.7 mg of protocatechualdehyde (b, 81.6% purity were obtained using the solvent system EtOAc–n-butanol (n-BuOH–FA–H2O (4:1:0.5:5, v/v. The structures of the eight pure compounds were confirmed by electrospray ionization-mass spectrometry (ESI-MS, 1H-NMR and 13C-NMR. To the best of our knowledge, compounds a–d and f were the first separated and reported from the Chimonanthus praecox flower extract.

  10. Gyrokinetic analysis of ion temperature gradient modes in the presence of sheared flows

    International Nuclear Information System (INIS)

    Artun, M.; Tang, W.M.

    1992-01-01

    The linearized gyrokinetic equation governing electrostatic microinstabilities in the presence of sheared equilibrium flow in both the z and y directions has been systematically derived for a sheared slab geometry, where in the large aspect ratio limit z and y directions correspond to the toroidal and poloidal directions respectively. In the familiar long perpendicular wavelength regime (κ perpendicular ρi > 1), the analysis leads to a comprehensive kinetic differential eigenmode equation which is solved numerically. The numerical results have been successfully cross-checked against analytic estimates in the fluid limit. For typical conditions, the Ion Temperature Gradient (ηi) modes are found to be stabilized for y-direction flows with a velocity shear scale comparable to that of the ion temperature gradient and velocities of a few percent of the sound speed. Sheared flows in the z-direction taken along are usually destabilizing, with the effect being independent of the sign of the flow. However, when both types are simultaneously considered, it is found that in the presence of shared z-direction flow, sheared y-direction flow can be either stabilizing or destabilizing depending on the relative sign of these flows. However, for sufficiently large values of υ' y the mode is completely stabilized regardless of the sign of υ' z υ' y . The importance of a proper kinetic treatment of this problem is supported by comparisons with fluid estimates. In particular, when such effects are favorable, significantly smaller values of sheared y-direction flow are required for stability than fluid estimates would indicate

  11. Carotid artery B-mode ultrasound image segmentation based on morphology, geometry and gradient direction

    Science.gov (United States)

    Sunarya, I. Made Gede; Yuniarno, Eko Mulyanto; Purnomo, Mauridhi Hery; Sardjono, Tri Arief; Sunu, Ismoyo; Purnama, I. Ketut Eddy

    2017-06-01

    Carotid Artery (CA) is one of the vital organs in the human body. CA features that can be used are position, size and volume. Position feature can used to determine the preliminary initialization of the tracking. Examination of the CA features can use Ultrasound. Ultrasound imaging can be operated dependently by an skilled operator, hence there could be some differences in the images result obtained by two or more different operators. This can affect the process of determining of CA. To reduce the level of subjectivity among operators, it can determine the position of the CA automatically. In this study, the proposed method is to segment CA in B-Mode Ultrasound Image based on morphology, geometry and gradient direction. This study consists of three steps, the data collection, preprocessing and artery segmentation. The data used in this study were taken directly by the researchers and taken from the Brno university's signal processing lab database. Each data set contains 100 carotid artery B-Mode ultrasound image. Artery is modeled using ellipse with center c, major axis a and minor axis b. The proposed method has a high value on each data set, 97% (data set 1), 73 % (data set 2), 87% (data set 3). This segmentation results will then be used in the process of tracking the CA.

  12. Gyrokinetic global analysis of ion temperature gradient driven mode in reversed shear tokamaks

    International Nuclear Information System (INIS)

    Idomura, Y.; Tokuda, S.; Kishimoto, Y.

    2003-01-01

    A new toroidal gyrokinetic particle code has been developed to study the ion temperature gradient driven (ITG) turbulence in reactor relevant tokamak parameters. We use a new method based on a canonical Maxwellian distribution F CM (P φ , ε, μ), which is defined by three constants of motion in the axisymmetric toroidal system, the canonical angular momentum P φ , the energy ε, and the magnetic moment μ. A quasi-ballooning representation enables linear and nonlinear high-m,n global calculations with a good numerical convergence. Conservation properties are improved by using the optimized loading method. From comprehensive linear global analyses over a wide range of an unstable toroidal mode number spectrum (n=0∼100) in large tokamak parameters (a/ρ ti =320∼460), properties of the ITG modes in reversed shear tokamaks are discussed. In the nonlinear simulation, it is found that a new method based on F CM can simulate a zonal flow damping correctly, and spurious zonal flow oscillations, which are observed in a conventional method based on a local Maxwellian distribution F LM (ψ, ε, μ), do not appear in the nonlinear regime. (author)

  13. Full-angle Negative Reflection with An Ultrathin Acoustic Gradient Metasurface: Floquet-Bloch Modes Perspective and Experimental Verification

    KAUST Repository

    Liu, Bingyi

    2017-07-01

    Metasurface with gradient phase response offers new alternative for steering the propagation of waves. Conventional Snell\\'s law has been revised by taking the contribution of local phase gradient into account. However, the requirement of momentum matching along the metasurface sets its nontrivial beam manipulation functionality within a limited-angle incidence. In this work, we theoretically and experimentally demonstrate that the acoustic gradient metasurface supports the negative reflection for full-angle incidence. The mode expansion theory is developed to help understand how the gradient metasurface tailors the incident beams, and the full-angle negative reflection occurs when the first negative order Floquet-Bloch mode dominates. The coiling-up space structures are utilized to build desired acoustic gradient metasurface and the full-angle negative reflections have been perfectly verified by experimental measurements. Our work offers the Floquet-Bloch modes perspective for qualitatively understanding the reflection behaviors of the acoustic gradient metasurface and enables a new degree of the acoustic wave manipulating.

  14. A self-organized criticality model for ion temperature gradient mode driven turbulence in confined plasma

    Science.gov (United States)

    Isliker, H.; Pisokas, Th.; Strintzi, D.; Vlahos, L.

    2010-08-01

    A new self-organized criticality (SOC) model is introduced in the form of a cellular automaton (CA) for ion temperature gradient (ITG) mode driven turbulence in fusion plasmas. Main characteristics of the model are that it is constructed in terms of the actual physical variable, the ion temperature, and that the temporal evolution of the CA, which necessarily is in the form of rules, mimics actual physical processes as they are considered to be active in the system, i.e., a heating process and a local diffusive process that sets on if a threshold in the normalized ITG R /LT is exceeded. The model reaches the SOC state and yields ion temperature profiles of exponential shape, which exhibit very high stiffness, in that they basically are independent of the loading pattern applied. This implies that there is anomalous heat transport present in the system, despite the fact that diffusion at the local level is imposed to be of a normal kind. The distributions of the heat fluxes in the system and of the heat out-fluxes are of power-law shape. The basic properties of the model are in good qualitative agreement with experimental results.

  15. A self-organized criticality model for ion temperature gradient mode driven turbulence in confined plasma

    International Nuclear Information System (INIS)

    Isliker, H.; Pisokas, Th.; Vlahos, L.; Strintzi, D.

    2010-01-01

    A new self-organized criticality (SOC) model is introduced in the form of a cellular automaton (CA) for ion temperature gradient (ITG) mode driven turbulence in fusion plasmas. Main characteristics of the model are that it is constructed in terms of the actual physical variable, the ion temperature, and that the temporal evolution of the CA, which necessarily is in the form of rules, mimics actual physical processes as they are considered to be active in the system, i.e., a heating process and a local diffusive process that sets on if a threshold in the normalized ITG R/L T is exceeded. The model reaches the SOC state and yields ion temperature profiles of exponential shape, which exhibit very high stiffness, in that they basically are independent of the loading pattern applied. This implies that there is anomalous heat transport present in the system, despite the fact that diffusion at the local level is imposed to be of a normal kind. The distributions of the heat fluxes in the system and of the heat out-fluxes are of power-law shape. The basic properties of the model are in good qualitative agreement with experimental results.

  16. Comparison of DNA double-strand break rejoining as measured by pulsed field gel electrophoresis, neutral sucrose gradient centrifugation and non-unwinding filter elution in irradiated plateau-phase CHO cells

    International Nuclear Information System (INIS)

    Iliakis, G.; Metzger, L.; Pantelias, G.

    1991-01-01

    The initial (up to 30 min) rate of DNA double-strand break (dsb) rejoining was measured in irradiated plateau-phase CHO cells, in a set of parallel experiments using the same cell suspension, by means of non-unwinding filter elution, neutral sucrose gradient centrifugation, and two pulsed-field gel electrophoresis assays: asymmetric field inversion gel electrophoresis (AFIGE) and clamped homogeneous electric field (CHEF) gel electrophoresis. The rate of DNA dsb rejoining was compared to the rate of rejoining of chromatin breaks measured, also in the same cell population, using the technique of premature chromosome condensation (PCC). Two radiation exposures, 25 Gy and/or 50 Gy, were used and applied to the individual parts of the experiments according to the sensitivity of the assay under investigation. The results suggest all major techniques currently used for assaying rejoining of DNA dsb give similar results, and indicate that more information is required before a direct correlation between rejoining of DNA dsb and rejoining of chromatin breaks can be established. (author)

  17. Generation of zonal flows by ion-temperature-gradient and related modes in the presence of neoclassical viscosity

    International Nuclear Information System (INIS)

    Mikhailovskii, A.B.; Smolyakov, A.I.; Kovalishen, E.A.; Shirokov, M.S.; Tsypin, V.S.; Galvao, R.M.O.

    2006-01-01

    Generation of zonal flows by primary waves that are more complex than those considered in the standard drift-wave model is studied. The effects of parallel ion velocity and ion perturbed temperature and the part of the nonlinear mode interaction proportional to the ion pressure are taken into account. This generalization of the standard model allows the analysis of generation of zonal flows by a rather wide variety of primary modes, including ion temperature gradients, ion sound, electron drift, and drift-sound modes. All the listed effects, which are present in the slab geometry model, are complemented by effects of neoclassical viscosity inherent to toroidal geometry. We show that the electrostatic potential of secondary small-scale modes is expressed in terms of a nonlinear shift of the mode frequency and interpret this shift in terms of the perpendicular and parallel Doppler, nonlinear Kelvin-Helmholtz (KH), and nonlinear ion-pressure-gradient effects. A basic assumption of our model is that the primary modes form a nondispersive monochromatic wave packet. The analysis of zonal-flow generation is performed following an approach similar to that of convective-cell theory. Neoclassical zonal-flow instabilities are separated into fast and slow ones, and these are divided into two varieties. The first of them is independent of the nonlinear KH effect, while the second one is sensitive to it

  18. Non-dissipative kinetic simulation and analytical solution of three-mode equations of ion temperature gradient instability

    International Nuclear Information System (INIS)

    Watanabe, T.-H.; Sugama, H.; Sato, T.

    1999-12-01

    A non-dissipative drift kinetic simulation scheme, which rigorously satisfies the time-reversibility, is applied to the three-mode coupling problem of the ion temperature gradient (ITG) instability. It is found from the simulation that the three-mode ITG system repeats growth and decay with a period which shows a logarithmic divergence for infinitesimal initial perturbations. Accordingly, time average of the mode amplitude vanishes, as the initial amplitude approaches to zero. An exact solution is analytically given for a class of initial conditions. An excellent agreement is confirmed between the analytical solution and numerical results. The results obtained here provide a useful reference for basic benchmarking of theories and simulation of the ITG modes. (author)

  19. Electron temperature gradient mode instability and stationary vortices with elliptic and circular boundary conditions in non-Maxwellian plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Haque, Q. [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Zakir, U. [Department of Physics, University of Peshawar, Khyber Pakhtun Khwa 25000 (Pakistan); Department of Physics, University of Malakand, Khyber Pakhtun Khwa 18800 (Pakistan); Qamar, A. [Department of Physics, University of Peshawar, Khyber Pakhtun Khwa 25000 (Pakistan)

    2015-12-15

    Linear and nonlinear dynamics of electron temperature gradient mode along with parallel electron dynamics is investigated by considering hydrodynamic electrons and non-Maxwellian ions. It is noticed that the growth rate of η{sub e}-mode driven linear instability decreases by increasing the value of spectral index and increases by reducing the ion/electron temperature ratio along the magnetic field lines. The eigen mode dispersion relation is also found in the ballooning mode limit. Stationary solutions in the form of dipolar vortices are obtained for both circular and elliptic boundary conditions. It is shown that the dynamics of both circular and elliptic vortices changes with the inclusion of inhomogeneity and non-Maxwellian effects.

  20. Electron temperature gradient mode instability and stationary vortices with elliptic and circular boundary conditions in non-Maxwellian plasmas

    Science.gov (United States)

    Haque, Q.; Zakir, U.; Qamar, A.

    2015-12-01

    Linear and nonlinear dynamics of electron temperature gradient mode along with parallel electron dynamics is investigated by considering hydrodynamic electrons and non-Maxwellian ions. It is noticed that the growth rate of ηe-mode driven linear instability decreases by increasing the value of spectral index and increases by reducing the ion/electron temperature ratio along the magnetic field lines. The eigen mode dispersion relation is also found in the ballooning mode limit. Stationary solutions in the form of dipolar vortices are obtained for both circular and elliptic boundary conditions. It is shown that the dynamics of both circular and elliptic vortices changes with the inclusion of inhomogeneity and non-Maxwellian effects.

  1. Explanation of L→H mode transition based on gradient stabilization of edge thermal fluctuations

    International Nuclear Information System (INIS)

    Stacey, W.M.

    1996-01-01

    A linear analysis of thermal fluctuations, using a fluid model which treats the large radial gradient related phenomena in the plasma edge, leads to a constraint on the temperature and density gradients for stabilization of edge temperature fluctuations. A temperature gradient, or conductive edge heat flux, threshold is identified. It is proposed that the L→H transition takes place when the conductive heat flux to the edge produces a sufficiently large edge temperature gradient to stabilize the edge thermal fluctuations. The consequences following from this mechanism for the L→H transition are in accord with observed phenomena associated with the L→H transition and with the observed parameter dependences of the power threshold. First, a constraint is established on the edge temperature and density gradients that are sufficient for the stability of edge temperature fluctuations. A slab approximation for the thin plasma edge and a fluid model connected to account for the large radial gradients present in the plasma edge are used. Equilibrium solutions are characterized by the value of the density and of its gradient L n -1 double-bond - n -1 , etc. Temperature fluctuations expanded about the equilibrium value are then used in the energy balance equation summed over plasma ions, electrons and impurities to obtain, after linearization, an expression for the growth rate ω of edge localized thermal fluctuations. Thermal stability of the equilibrium solution requires ω ≤ 0, which establishes a constraint that must be satisfied by L n -1 and L T -1 . The limiting value of the constraint (ω = 0) leads to an expression for the minimum value of that is sufficient for thermal stability, for a given value of L T -1. It is found that there is a minimum value of the temperature gradient, (L T -1 ) min that is necessary for a stable solution to exist for any value of L n -1

  2. Coupling of ion temperature gradient and trapped electron modes in the presence of impurities in tokamak plasmas

    Science.gov (United States)

    Du, Huarong; Wang, Zheng-Xiong; Dong, J. Q.; Liu, S. F.

    2014-05-01

    The coupling of ion temperature gradient (ITG or ηi) mode and trapped electron mode (TEM) in the presence of impurity ions is numerically investigated in toroidal collisionless plasmas, using the gyrokinetic integral eigenmode equation. A framework for excitations of the ITG modes and TEMs with respect to their driving sources is formulated first, and then the roles of impurity ions played in are analyzed comprehensively. In particular, the characteristics of the ITG and TEM instabilities in the presence of impurity ions are emphasized for both strong and weak coupling (hybrid and coexistent) cases. It is found that the impurity ions with inwardly (outwardly) peaked density profiles have stabilizing (destabilizing) effects on the hybrid (namely the TE-ITG) modes in consistence with previous works. A new finding of this work is that the impurity ions have stabilizing effects on TEMs in small ηi (ηi≤1) regime regardless of peaking directions of their density profiles whereas the impurity ions with density gradient Lez=Lne/Lnz>1 (LezTEMs in large ηi (ηi≥1) regime. In addition, the dependences of the growth rate, real frequency, eigenmode structure, and wave spectrum on charge concentration, charge number, and mass of impurity ions are analyzed in detail. The necessity for taking impurity ion effects on the features of turbulence into account in future transport experimental data analyses is also discussed.

  3. Formation of tripolar vortices in toroidal ion-temperature-gradient driven modes in the presence of dust contamination

    International Nuclear Information System (INIS)

    Mirza, Arshad M.; Qamar, Anisa; Khan, M. Yaqub; Ayub, M.

    2007-01-01

    A system of nonlinear equations that governs the dynamics of toroidal-ion-temperature-gradient (TITG) driven modes in the presence of dust contamination is presented. In the linear limit, a local dispersion relation is derived and analyzed for a flat density profile case. In the nonlinear case, and by taking some specific profiles of equilibrium density, ion temperature, magnetic field, and sheared plasma flows, the stationary solutions of the nonlinear system can be represented in the form of a tripolar vortex solution. Numerical results obtained in the present study show that the inclusion of dust modifies the nonlinear vortical structures, and the amplitude of the normalized potential is found to be increased in the presence of negatively charged dust grains. The results of our present investigation would be useful to understand some linear as well as nonlinear properties of TITG modes in a dust-contaminated tokamak plasma

  4. Nonlinear features of the electron temperature gradient mode and electron thermal transport in tokamaks

    International Nuclear Information System (INIS)

    Kaw, P.K.; Singh, R.; Weiland, J.G.

    2001-01-01

    Analytical investigations of several linear and nonlinear features of ETG turbulence are reported. The linear theory includes effects such as finite beta induced electromagnetic shielding, coupling to electron magnetohydrodynamic modes like whistlers etc. It is argued that nonlinearly, turbulence and transport are dominated by radially extended modes called 'streamers'. A nonlinear mechanism generating streamers based on a modulational instability theory of the ETG turbulence is also presented. The saturation levels of the streamers using a Kelvin Helmholtz secondary instability mechanism are calculated and levels of the electron thermal transport due to streamers are estimated. (author)

  5. Gyrokinetic theory of slab universal modes and the non-existence of the gradient drift coupling (GDC) instability

    Science.gov (United States)

    Rogers, Barrett N.; Zhu, Ben; Francisquez, Manaure

    2018-05-01

    A gyrokinetic linear stability analysis of a collisionless slab geometry in the local approximation is presented. We focus on k∥=0 universal (or entropy) modes driven by plasma gradients at small and large plasma β. These are small scale non-MHD instabilities with growth rates that typically peak near k⊥ρi˜1 and vanish in the long wavelength k⊥→0 limit. This work also discusses a mode known as the Gradient Drift Coupling (GDC) instability previously reported in the gyrokinetic literature, which has a finite growth rate γ=√{β/[2 (1 +β)] }Cs/|Lp| with Cs2=p0/ρ0 for k⊥→0 and is universally unstable for 1 /Lp≠0 . We show that the GDC instability is a spurious, unphysical artifact that erroneously arises due to the failure to respect the total equilibrium pressure balance p0+B02/(8 π)=constant , which renders the assumption B0'=0 inconsistent if p0'≠0 .

  6. Gradient Scouting in Reversed-Phase HPLC Revisited

    Science.gov (United States)

    Alcazar, A.; Jurado, J. M.; Gonzalez, A. G.

    2011-01-01

    Gradient scouting is the best way to decide the most suitable elution mode in reversed-phase high-performance liquid chromatography (RP-HPLC). A simple rule for this decision involves the evaluation of the ratio [delta]t/t[subscript G] (where [delta]t is the difference in the retention time between the last and the first peak and t[subscript G] is…

  7. Analysis of the Cause of High External Q Modes in the JLab High Gradient Prototype Cryomodule Renascence

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.; Akcelik, V.; Xiao, L.; Lee, L.; Ng, C.; Ko, K.; /SLAC; Wang, H.; Marhauser, F.; Sekutowicz, J.; Reece, C.; Rimmer, R.; /Jefferson Lab

    2008-06-27

    The Renascence cryomodule [1] installed in CEBAF in 2007 consists of 8 cavities as shown in Figure 1. The first three cavities (No.1-No.3) in the upstream end are of the Low Loss (LL) shape design, and the remaining 5 cavities (No.4-No.8) on the beam downstream end are the High Gradient (HG) shape design. The fundamental power couplers (FPCs) are the rectangular waveguides, and the little cylindrical structures are the HOM couplers. The locations of the FPC in the last four cavities are mirrored about the beam z axis. Cavities No.4 and No.5 form a back-to-back cavity pair. Among the HG cavities installed in the Renascence cryomodule, the only identifiable difference from their fabrication documentation is that cavity No.5 received an extra EBW pass on one equator weld, specifically cell 5. The non-uniform mechanical tuning required to compensate the fundamental mode tune and flatness for the extra shrinkage of this cell is believed to contribute the most significant differences from the other HG cavities. Beam based instability studies on this cryomodule in CEBAF have shown a significant beam breakup (BBU) threshold current reduction, well below design value. Frequency spectrum peaked by the off-sided beam power indicated the cause is due to abnormal high Q modes in the cavity No.5. Measured beam off-axis position at the cavity No.5 does not correspond to the shunt impedances calculated for an ideal cavity. Low power RF measurements have identified that the problematic modes are in the second dipole band (TM110 like). Three of the modes have external Qs two orders magnitude higher than the others, while the rest of modes in the first two dipole bands are normal in terms of the design values. The cause of this abnormality and the future impact on the BBU was not able to be resolved due to the limitations of information that can be obtained from the measurements. It is important to understand the cause of this abnormality so that effective QA/QC measures can be

  8. An Inexpensive Digital Gradient Controller for HPLC.

    Science.gov (United States)

    Brady, James E.; Carr, Peter W.

    1983-01-01

    Use of gradient elution techniques in high performance liquid chromatography (HPLC) is often essential for direct separation of complex mixtures. Since most commercial controllers have features that are of marginal value for instructional purposes, a low-cost controller capable of illustrating essential features of gradient elution was developed.…

  9. Full-angle Negative Reflection with An Ultrathin Acoustic Gradient Metasurface: Floquet-Bloch Modes Perspective and Experimental Verification

    KAUST Repository

    Liu, Bingyi; Zhao, Jiajun; Xu, Xiaodong; Zhao, Wenyu; Jiang, Yongyuan

    2017-01-01

    Metasurface with gradient phase response offers new alternative for steering the propagation of waves. Conventional Snell's law has been revised by taking the contribution of local phase gradient into account. However, the requirement of momentum

  10. Fast ion stabilization of the ion temperature gradient driven modes in the Joint European Torus hybrid-scenario plasmas: a trigger mechanism for internal transport barrier formation

    Energy Technology Data Exchange (ETDEWEB)

    Romanelli, M; Zocco, A [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB (United Kingdom); Crisanti, F, E-mail: Michele.Romanelli@ccfe.ac.u [Associazione Euratom-ENEA sulla Fusione, C.R. Frascati, Frascati (Italy)

    2010-04-15

    Understanding and modelling turbulent transport in thermonuclear fusion plasmas are crucial for designing and optimizing the operational scenarios of future fusion reactors. In this context, plasmas exhibiting state transitions, such as the formation of an internal transport barrier (ITB), are particularly interesting since they can shed light on transport physics and offer the opportunity to test different turbulence suppression models. In this paper, we focus on the modelling of ITB formation in the Joint European Torus (JET) [1] hybrid-scenario plasmas, where, due to the monotonic safety factor profile, magnetic shear stabilization cannot be invoked to explain the transition. The turbulence suppression mechanism investigated here relies on the increase in the plasma pressure gradient in the presence of a minority of energetic ions. Microstability analysis of the ion temperature gradient driven modes (ITG) in the presence of a fast-hydrogen minority shows that energetic ions accelerated by the ion cyclotron resonance heating (ICRH) system (hydrogen, n{sub H,fast}/n{sub D,thermal} up to 10%, T{sub H,fast}/T{sub D,thermal} up to 30) can increase the pressure gradient enough to stabilize the ITG modes driven by the gradient of the thermal ions (deuterium). Numerical analysis shows that, by increasing the temperature of the energetic ions, electrostatic ITG modes are gradually replaced by nearly electrostatic modes with tearing parity at progressively longer wavelengths. The growth rate of the microtearing modes is found to be lower than that of the ITG modes and comparable to the local E x B-velocity shearing rate. The above mechanism is proposed as a possible trigger for the formation of ITBs in this type of discharges.

  11. Prediction of the chromatographic retention of acid-base compounds in pH buffered methanol-water mobile phases in gradient mode by a simplified model.

    Science.gov (United States)

    Andrés, Axel; Rosés, Martí; Bosch, Elisabeth

    2015-03-13

    Retention of ionizable analytes under gradient elution depends on the pH of the mobile phase, the pKa of the analyte and their evolution along the programmed gradient. In previous work, a model depending on two fitting parameters was recommended because of its very favorable relationship between accuracy and required experimental work. It was developed using acetonitrile as the organic modifier and involves pKa modeling by means of equations that take into account the acidic functional group of the compound (carboxylic acid, protonated amine, etc.). In this work, the two-parameter predicting model is tested and validated using methanol as the organic modifier of the mobile phase and several compounds of higher pharmaceutical relevance and structural complexity as testing analytes. The results have been quite good overall, showing that the predicting model is applicable to a wide variety of acid-base compounds using mobile phases prepared with acetonitrile or methanol. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Derivation of the threshold condition for the ion temperature gradient mode with an inverted density profile from a simple physics picture

    Science.gov (United States)

    Jhang, Hogun

    2018-05-01

    We show that the threshold condition for the toroidal ion temperature gradient (ITG) mode with an inverted density profile can be derived from a simple physics argument. The key in this picture is that the density inversion reduces the ion compression due to the ITG mode and the electron drift motion mitigates the poloidal potential build-up. This condition reproduces the same result that has been reported from a linear gyrokinetic calculation [T. S. Hahm and W. M. Tang, Phys. Fluids B 1, 1185 (1989)]. The destabilizing role of trapped electrons in toroidal geometry is easily captured in this picture.

  13. Size distribution of DNA molecules recovered from non-denaturing filter elution

    International Nuclear Information System (INIS)

    Bloecher, D.; Iliakis, G.

    1991-01-01

    DNA fragments removed from the filter during non-denaturing filter elution were collected and loaded on top of neutral sucrose gradients. Their size distribution was determined by low-speed centrifugation in neutral sucrose gradients. The average size of eluted DNA was found to be approximately 110 S; the average size of DNA collected after short elution times was found to be slightly larger than after long elution times. It is concluded that the size of eluted DNA fragments is not correlated with elution rate, and it is proposed that shear forces generated at the filter pores cause degradation of the DNA. Comparison of sedimentation profiles of carefully prepared cellular DNA before and after elution revealed that generated shear forces during elution break down DNA to an extent equivalent to around 20 000 DNA double-strand breaks (dsb) per G 1 cell. The size of DNA fragments decreased with increasing radiation dose; five times more dsb were found than expected after exposure to radiation alone. It is proposed that excess of dsb may derive from the transformation of other radiation-induced lesions to dsb under the action of shear forces generated during elution. (author)

  14. Using contemporary liquid chromatography theory and technology to improve capillary gradient ion-exchange separations.

    Science.gov (United States)

    Wouters, Bert; Broeckhoven, Ken; Wouters, Sam; Bruggink, Cees; Agroskin, Yury; Pohl, Christopher A; Eeltink, Sebastiaan

    2014-11-28

    The gradient-performance limits of capillary ion chromatography have been assessed at maximum system pressure (34.5 MPa) using capillary columns packed with 4.1 μm macroporous anion-exchange particles coated with 65 nm positively-charged nanobeads. In analogy to the van-Deemter curve, the gradient performance was assessed applying different flow rates, while decreasing the gradient time inversely proportional to the increase in flow rate in order to maintain the same retention properties. The gradient kinetic-performance limits were determined at maximum system pressure, applying tG/t0=5, 10, and 20. In addition, the effect of retention on peak width was assessed in gradient mode for mono-, di-, and trivalent inorganic anions. The peak width of late-eluting ions can be significantly reduced by using concave gradient, resulting in better detection sensitivity. A signal enhancement factor of 8 was measured for a late-eluting ion when applying a concave instead of a linear gradient. For the analysis of a complex anion mixture, a coupled column with a total length of 1.05 m was operated at the kinetic-performance limit applying a linear 250 min gradient (tG/t0=10). The peak capacity varied between 200 and 380 depending on analyte retention, and hence on charge and size of the ion. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. THE ORIGIN AND EVOLUTION OF METALLICITY GRADIENTS: PROBING THE MODE OF MASS ASSEMBLY AT z ≅ 2

    International Nuclear Information System (INIS)

    Jones, Tucker; Ellis, Richard S.; Richard, Johan; Jullo, Eric

    2013-01-01

    We present and discuss measurements of the gas-phase metallicity gradient in four gravitationally lensed galaxies at z = 2.0-2.4 based on adaptive optics-assisted imaging spectroscopy with the Keck II telescope. Three galaxies with well-ordered rotation reveal metallicity gradients with lower gas-phase metallicities at larger galactocentric radii. Two of these display gradients much steeper than found locally, while a third has one similar to that seen in local disk galaxies. The fourth galaxy exhibits complex kinematics indicative of an ongoing merger and reveals an 'inverted' gradient with lower metallicity in the central regions. By comparing our sample to similar data in the literature for lower redshift galaxies, we determine that, on average, metallicity gradients must flatten by a factor of 2.6 ± 0.9 between z = 2.2 and the present epoch. This factor is in rough agreement with the size growth of massive galaxies, suggesting that inside-out growth can account for the evolution of metallicity gradients. Since the addition of our new data provides the first indication of a coherent picture of this evolution, we develop a simple model of chemical evolution to explain the collective data. We find that metallicity gradients and their evolution can be explained by the inward radial migration of gas together with a radial variation in the mass loading factor governing the ratio of outflowing gas to the local star formation rate. Average mass loading factors of ∼< 2 are inferred from our model in good agreement with direct measurements of outflowing gas in z ≅ 2 galaxies.

  16. Measurement of deuterium density profiles in the H-mode steep gradient region using charge exchange recombination spectroscopy on DIII-D.

    Science.gov (United States)

    Haskey, S R; Grierson, B A; Burrell, K H; Chrystal, C; Groebner, R J; Kaplan, D H; Pablant, N A; Stagner, L

    2016-11-01

    Recent completion of a thirty two channel main-ion (deuterium) charge exchange recombination spectroscopy (CER) diagnostic on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] enables detailed comparisons between impurity and main-ion temperature, density, and toroidal rotation. In a H-mode DIII-D discharge, these new measurement capabilities are used to provide the deuterium density profile, demonstrate the importance of profile alignment between Thomson scattering and CER diagnostics, and aid in determining the electron temperature at the separatrix. Sixteen sightlines cover the core of the plasma and another sixteen are densely packed towards the plasma edge, providing high resolution measurements across the pedestal and steep gradient region in H-mode plasmas. Extracting useful physical quantities such as deuterium density is challenging due to multiple photoemission processes. These challenges are overcome using a detailed fitting model and by forward modeling the photoemission using the FIDASIM code, which implements a comprehensive collisional radiative model.

  17. The Indicating FTA Elute Cartridge

    Science.gov (United States)

    de Bie, Roosmarie P.; Schmeink, Channa E.; Bakkers, Judith M.J.E.; Snijders, Peter J.F.; Quint, Wim G.V.; Massuger, Leon F.A.G.; Bekkers, Ruud L.M.; Melchers, Willem J.G.

    2011-01-01

    The clinically validated high-risk human papillomavirus (hrHPV) Hybrid Capture 2 (HC2) and GP5+/6+-PCR assays were analyzed on an Indicating FTA Elute cartridge (FTA cartridge). The FTA cartridge is a solid dry carrier that allows safe transport of cervical samples. FTA cartridge samples were compared with liquid-based samples for hrHPV and high-grade cervical intraepithelial neoplasia (CIN) detection. One cervical sample was collected in a liquid-based medium, and one was applied to the FTA cartridge. DNA was eluted directly from the FTA cartridge by a simple elution step. HC2 and GP5+/6+-PCR assays were performed on both the liquid-based and the FTA-eluted DNA of 88 women. Overall agreement between FTA and liquid-based samples for the presence of hrHPV was 90.9% with GP5+/6+-PCR and 77.3% with HC2. The sensitivity for high-grade CIN of hrHPV testing on the FTA cartridges was 84.6% with GP5+/6+-PCR and only 53.8% with HC2. By comparison, these sensitivities on liquid-based samples were 92.3% and 100% for GP5+/6+-PCR and HC2, respectively. Therefore, the FTA cartridge shows reasonably good overall agreement for hrHPV detection with liquid-based media when using GP5+/6+-PCR but not HC2 testing. Even with GP5+/6+-PCR, the FTA cartridge is not yet capable of detecting all high-grade CIN lesions. PMID:21704269

  18. Development of tool for simulating the effect of radial electric fields on Ion-Temperature-Gradient modes in 3D configurations

    International Nuclear Information System (INIS)

    Eriksson, Lars

    2003-03-01

    The heat flux level observed in magnetic plasma confinement experiments such as tokamaks is much higher than what can be explained from neoclassical theory. There is a strong interest in the controlled nuclear fusion community to fully understand this phenomenon, called anomalous transport. One idea is that radial electric fields play a key role in the stabilization process of the electrostatic instabilities called micro instabilities that are considered responsible for the anomalous heat flux. This work studies the effect of a static ad-hoc radial electric field on microinstabilities, especially the ion temperature gradient (ITG) driven mode, within the frame of a global 3D gyrokinetic model. This will make it possible to extend the simulations done in tokamaks and helically symmetric systems to fully 313 magnetic configurations. Technically the work consists of extending the 3D gyrokinetic code Euterpe to also include the effect of the drifts induced by an imposed radial electrostatic potential. Simulations are performed in tokamak and helically symmetric configurations. The results indicate that this modified version of Euterpe can be used in studying more complex 3D fusion devices

  19. Elution behaviors of elements from the hair

    International Nuclear Information System (INIS)

    Akashi, Junko; Fukushima, Ichiro; Imahori, Akira

    1981-01-01

    The elution of the neutron activated elements out of hair soaked in some organic solvents and EDTA solution was studied. Soakage of the hair sample, which was washed with water and acetone in advance as IAEA's proposal, in ether and acetone for 30 minutes each resulted in no elution of Hg, Zn, Co and Se. Elution of Zn and Co from the powdered hair sample soaked in 0.1 M EDTA solution was rapid, while Zn did not elute out from the cut hair (2 -- 3 mm length) on the same condition. Hg, Se and Au were not eluted out by 0.1 M EDTA solution in the both case of cut hair and of powdered hair. Br was removed by 0.1 M EDTA solution from the cut hair and from the powdered hair with equal ease. (author)

  20. Zotarolimus-eluting vs. sirolimus-eluting coronary stents in patients with and without acute coronary syndromes

    DEFF Research Database (Denmark)

    Thim, Troels; Maeng, Michael; Kaltoft, Anne Kjer

    2012-01-01

    To compare clinical outcomes among patients with acute coronary syndrome treated with zotarolimus-eluting and sirolimus-eluting stents in the SORT OUT III trial.......To compare clinical outcomes among patients with acute coronary syndrome treated with zotarolimus-eluting and sirolimus-eluting stents in the SORT OUT III trial....

  1. XIENCE V everolimus-eluting coronary stent system: a novel second generation drug-eluting stent

    NARCIS (Netherlands)

    Beijk, Marcel A. M.; Piek, Jon J.

    2007-01-01

    Drug-eluting stents (DES) have been shown to be safe and significantly reduce clinical events and angiographic restenosis in the percutaneous treatment of coronary artery disease. Currently, three DES have been approved in Europe and Northern America: the sirolimus-eluting stent (SES), the

  2. Systematic generation of buffer systems for pH gradient ion exchange chromatography and their application.

    Science.gov (United States)

    Kröner, Frieder; Hubbuch, Jürgen

    2013-04-12

    pH gradient protein separations are widely used techniques in the field of protein analytics, of which isoelectric focusing is the most well known application. The chromatographic variant, based on the formation of pH gradients in ion exchange columns is only rarely applied due to the difficulties to form controllable, linear pH gradients over a broad pH range. This work describes a method for the systematic generation of buffer compositions with linear titration curves, resulting in well controllable pH gradients. To generate buffer compositions with linear titration curves an in silico method was successfully developed. With this tool, buffer compositions for pH gradient ion exchange chromatography with pH ranges spanning up to 7.5 pH units were established and successfully validated. Subsequently, the buffer systems were used to characterize the elution behavior of 22 different model proteins in cation and anion exchange pH gradient chromatography. The results of both chromatographic modes as well as isoelectric focusing were compared to describe differences in between the methods. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. EVALUATION OF PETROLEUM HYDROCARBONS ELUTION FROM SOIL

    Directory of Open Access Journals (Sweden)

    Janina Piekutin

    2015-06-01

    Full Text Available The paper presents studies on oil removal from soil by means of water elution with a help of shaking out the contaminants from the soil. The tests were performed on simulated soil samples contaminated with a mixture of petroleum hydrocarbons. The study consisted in recording the time influence and the number of elution cycles to remove contaminants from the soil. The samples were then subject to the determination of petroleum hydrocarbons, aliphatic hydrocarbons, and BTEX compounds (benzene, toluene, ethylbenzene, xylene. Due to adding various concentrations of petroleum into particular soil samples and applying different shaking times, it was possible to find out the impact of petroleum content and sample shaking duration on the course and possibility of petroleum substances removal by means of elution process.

  4. Softening and elution of monomers in ethanol

    DEFF Research Database (Denmark)

    Benetti, Ana Raquel; Asmussen, Erik; Munksgaard, E Christian

    2009-01-01

    The purpose of this study was to investigate the effect of light-curing protocol on softening and elution of monomers in ethanol as measured on a model polymer. It was a further aim to correlate the measured values with previously reported data on degree of conversion and glass transition...

  5. Gyrokinetic particle-in-cell global simulations of ion-temperature-gradient and collisionless-trapped-electron-mode turbulence in tokamaks

    International Nuclear Information System (INIS)

    Jolliet, S.

    2009-02-01

    The goal of thermonuclear fusion research is to provide power plants, that will be able to produce one gigawatt of electricity. Among the different ways to achieve fusion, the tokamak, based on magnetic confinement, is the most promising one. A gas is heated up to hundreds of millions of degrees and becomes a plasma, which is maintained - or confined - in a toroidal vessel by helical magnetic field lines. Then, deuterium and tritium are injected and fuse to create an α particle and an energetic neutron. In order to have a favorable power balance, the power produced by fusion reactions must exceed the power needed to heat the plasma and the power losses. This can be cast in a very simple expression which stipulates that the product of the density, the temperature and the energy confinement time must exceed some given value. Unfortunately, present-days tokamaks are not able to reach this condition, mostly due to plasma turbulence. The latter phenomenon enhances the heat losses and degrades the energy confinement time, which cannot be predicted by analytical theories such as the so-called neoclassical theory in which the heat losses are caused by Coulomb collisions. Therefore, numerical simulations are being developed to model plasma turbulence, mainly caused by the Ion and Electron Temperature-Gradient and the Trapped-Electron-Mode (TEM) instabilities. The plasma is described by a distribution function which evolves according to the Vlasov equation. The electromagnetic fields created by the particles are self-consistently obtained through Maxwell’s equations. The resulting Vlasov-Maxwell system is greatly simplified by using the gyrokinetic theory, which consists, through an appropriate ordering, of eliminating the fast gyromotion (compared to the typical frequency of instabilities). Nevertheless, it is still extremely difficult to solve this system numerically due to the large range of time and spatial scales to be resolved. In this thesis, the Vlasov

  6. Effect of pre- and post-column band broadening on the performance of high-speed chromatography columns under isocratic and gradient conditions.

    Science.gov (United States)

    Vanderlinden, Kim; Broeckhoven, Ken; Vanderheyden, Yoachim; Desmet, Gert

    2016-04-15

    We report on the results of an experimental and theoretical study of the effect of the extra-column band broadening (ECBB) on the performance of narrow-bore columns filled with the smallest particles that are currently commercially available. Emphasis is on the difference between the effect of ECBB under gradient and isocratic conditions, as well as on the ability to model and predict the ECBB effects using well-established band broadening expressions available from the theory of chromatography. The fine details and assumptions that need to be taken into account when using these expressions are discussed. The experiments showed that, the steeper the gradient, the more pronounced the extra-column band broadening losses become. Whereas the pre-column band broadening can in both isocratic and gradient elution be avoided by playing on the possibilities to focus the analytes on top of the column (e.g. by using the POISe injection method when running isocratic separations), the post-column extra-column band broadening is inescapable in both cases. Inducing extra-column band broadening by changing the inner diameter of the post-column tubing from 65 to 250 μm, we found that all peaks in the chromatogram are strongly affected (around a factor of 1.9 increase in relative peak width) when running steep gradients, while usually only the first eluting peak was affected in the isocratic mode or when running shallow gradients (factor 1.6-1.8 increase in relative peak width for the first eluting analyte). Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Elution of Monomers from Provisional Composite Materials

    Directory of Open Access Journals (Sweden)

    Simon Daniel Schulz

    2015-01-01

    Full Text Available The aim of this study was to evaluate the elution of substances from different materials used for the manufacturing of temporary indirect restorations, after storage in saliva and ethanol 75%. 10 samples of three chemically cured materials (Protemp 3 Garant, Systemp.c&b, and Trim and one light-cured material (Clip F were stored in saliva and ethanol 75% for 24 h, 7, and days 28 days. From the storage media at each time period, samples were prepared and analysed by LC-MS/MS, in order to access the elution of monomers. The results differed among the materials (P ≤ 0.05. No monomers were detected in the samples of Protemp 3 Garant and Clip F. Substances were detected only in ethanol samples of Systemp.c&b and Trim. The amount of BisGMA, TEGDMA, and UDMA 2 released from Systemp.c&b was higher compared to Trim. Storage time affected the release of substances (P ≤ 0.05. The highest release was observed within the first 24 h. It can be concluded that provisional resin composite materials do not show high release of monomers and this release is material dependent. However, the detection of additional peaks during the analysis, suggesting the formation of by-products of the eluted substances, may not be in favour of these materials with respect to their toxicity.

  8. Innovative Elution Processes for Recovering Uranium from Seawater

    International Nuclear Information System (INIS)

    Wai, Chien; Tian, Guoxin; Janke, Christopher

    2014-01-01

    Utilizing amidoxime-based polymer sorbents for extraction of uranium from seawater has attracted considerable interest in recent years. Uranium collected in the sorbent is recovered typically by elution with an acid. One drawback of acid elution is deterioration of the sorbent which is a significant factor that limits the economic competitiveness of the amidoxime-based sorbent systems for sequestering uranium from seawater. Developing innovative elution processes to improve efficiency and to minimize loss of sorbent capacity become essential in order to make this technology economically feasible for large-scale industrial applications. This project has evaluated several elution processes including acid elution, carbonate elution, and supercritical fluid elution for recovering uranium from amidoxime-based polymer sorbents. The elution efficiency, durability and sorbent regeneration for repeated uranium adsorption- desorption cycles in simulated seawater have been studied. Spectroscopic techniques are used to evaluate chemical nature of the sorbent before and after elution. A sodium carbonate-hydrogen peroxide elution process for effective removal of uranium from amidoxime-based sorbent is developed. The cause of this sodium carbonate and hydrogen peroxide synergistic leaching of uranium from amidoxime-based sorbent is attributed to the formation of an extremely stable uranyl peroxo-carbonato complex. The efficiency of uranium elution by the carbonate-hydrogen peroxide method is comparable to that of the hydrochloric acid elution but damage to the sorbent material is much less for the former. The carbonate- hydrogen peroxide elution also does not need any elaborate step to regenerate the sorbent as those required for hydrochloric acid leaching. Several CO2-soluble ligands have been tested for extraction of uranium from the sorbent in supercritical fluid carbon dioxide. A mixture of hexafluoroacetylacetone and tri-n-butylphosphate shows the best result but uranium

  9. Innovative Elution Processes for Recovering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Wai, Chien [Univ. of Idaho, Moscow, ID (United States); Tian, Guoxin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Janke, Christopher [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-05-29

    Utilizing amidoxime-based polymer sorbents for extraction of uranium from seawater has attracted considerable interest in recent years. Uranium collected in the sorbent is recovered typically by elution with an acid. One drawback of acid elution is deterioration of the sorbent which is a significant factor that limits the economic competitiveness of the amidoxime-based sorbent systems for sequestering uranium from seawater. Developing innovative elution processes to improve efficiency and to minimize loss of sorbent capacity become essential in order to make this technology economically feasible for large-scale industrial applications. This project has evaluated several elution processes including acid elution, carbonate elution, and supercritical fluid elution for recovering uranium from amidoxime-based polymer sorbents. The elution efficiency, durability and sorbent regeneration for repeated uranium adsorption- desorption cycles in simulated seawater have been studied. Spectroscopic techniques are used to evaluate chemical nature of the sorbent before and after elution. A sodium carbonate-hydrogen peroxide elution process for effective removal of uranium from amidoxime-based sorbent is developed. The cause of this sodium carbonate and hydrogen peroxide synergistic leaching of uranium from amidoxime-based sorbent is attributed to the formation of an extremely stable uranyl peroxo-carbonato complex. The efficiency of uranium elution by the carbonate-hydrogen peroxide method is comparable to that of the hydrochloric acid elution but damage to the sorbent material is much less for the former. The carbonate- hydrogen peroxide elution also does not need any elaborate step to regenerate the sorbent as those required for hydrochloric acid leaching. Several CO2-soluble ligands have been tested for extraction of uranium from the sorbent in supercritical fluid carbon dioxide. A mixture of hexafluoroacetylacetone and tri-n-butylphosphate shows the best result but uranium

  10. A switch from a gradient to a threshold mode in the regulation of a transcriptional cascade promotes robust execution of meiosis in budding yeast.

    Directory of Open Access Journals (Sweden)

    Vyacheslav Gurevich

    Full Text Available Tight regulation of developmental pathways is of critical importance to all organisms, and is achieved by a transcriptional cascade ensuring the coordinated expression of sets of genes. We aimed to explore whether a strong signal is required to enter and complete a developmental pathway, by using meiosis in budding yeast as a model. We demonstrate that meiosis in budding yeast is insensitive to drastic changes in the levels of its consecutive positive regulators (Ime1, Ime2, and Ndt80. Entry into DNA replication is not correlated with the time of transcription of the early genes that regulate this event. Entry into nuclear division is directly regulated by the time of transcription of the middle genes, as premature transcription of their activator NDT80, leads to a premature entry into the first meiotic division, and loss of coordination between DNA replication and nuclear division. We demonstrate that Cdk1/Cln3 functions as a negative regulator of Ime2, and that ectopic expression of Cln3 delays entry into nuclear division as well as NDT80 transcription. Because Ime2 functions as a positive regulator for premeiotic DNA replication and NDT80 transcription, as well as a negative regulator of Cdk/Cln, we suggest that a double negative feedback loop between Ime2 and Cdk1/Cln3 promotes a bistable switch from the cell cycle to meiosis. Moreover, our results suggest a regulatory mode switch that ensures robust meiosis as the transcription of the early meiosis-specific genes responds in a graded mode to Ime1 levels, whereas that of the middle and late genes as well as initiation of DNA replication, are regulated in a threshold mode.

  11. Comprehensive analysis of pharmaceutical products using simultaneous mixed-mode (ion-exchange/reversed-phase) and hydrophilic interaction liquid chromatography.

    Science.gov (United States)

    Kazarian, Artaches A; Nesterenko, Pavel N; Soisungnoen, Phimpha; Burakham, Rodjana; Srijaranai, Supalax; Paull, Brett

    2014-08-01

    Liquid chromatographic assays were developed using a mixed-mode column coupled in sequence with a hydrophilic interaction liquid chromatography column to allow the simultaneous comprehensive analysis of inorganic/organic anions and cations, active pharmaceutical ingredients, and excipients (carbohydrates). The approach utilized dual sample injection and valve-mediated column switching and was based upon a single high-performance liquid chromatography gradient pump. The separation consisted of three distinct sequential separation mechanisms, namely, (i) ion-exchange, (ii) mixed-mode interactions under an applied dual gradient (reversed-phase/ion-exchange), and (iii) hydrophilic interaction chromatography. Upon first injection, the Scherzo SS C18 column (Imtakt) provided resolution of inorganic anions and cations under isocratic conditions, followed by a dual organic/salt gradient to elute active pharmaceutical ingredients and their respective organic counterions and potential degradants. At the top of the mixed-mode gradient (high acetonitrile content), the mobile phase flow was switched to a preconditioned hydrophilic interaction liquid chromatography column, and the standard/sample was reinjected for the separation of hydrophilic carbohydrates, some of which are commonly known excipients in drug formulations. The approach afforded reproducible separation and resolution of up to 23 chemically diverse solutes in a single run. The method was applied to investigate the composition of commercial cough syrups (Robitussin®), allowing resolution and determination of inorganic ions, active pharmaceutical ingredients, excipients, and numerous well-resolved unknown peaks. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Hypotonic elution, a new desorption principle in immunoadsorbent chromatography

    DEFF Research Database (Denmark)

    Danielsen, Erik Michael; Sjöström, H; Norén, O

    1982-01-01

    of finding an efficient means of elution which is not denaturing to neither the purified enzyme nor the immunoadsorbent column. Common properties of the microvillar enzymes with regard to amphiphilicity, glycosylation or subunit composition could hypothetically account for the similar elution properties...

  13. Production of 99Tc generators with automatic elution

    International Nuclear Information System (INIS)

    Mengatti, J.; Yanagawa, S.T.I.; Mazzarro, E.; Gasiglia, H.T.; Rela, P.R.; Silva, C.P.G. da; Pereira, N.P.S. de.

    1983-10-01

    The improvements performed on the routine production of sup(99m) Tc-generators at the Instituto de Pesquisas Energeticas e Nucleares-CNEN/SP, are described. The old model generators (manual elution of sup(99m) Tc) were substituted by automatically eluted generators (Vacuum system). The alumina column, elution system and acessories were modified; the elution time was reduced from 60 to 20-30 seconds. The new generators give 80-90% elution yields using six mililiters of sodium chloride 0,9% as sup(99m) Tc eluant instead of the 10 mililiters necessary to eluate the old generators. So, the radioactive concentrations are now 70% higher. The radioactive, radiochemical, chemical and microbiological criteria were examinated for sup(99m) Tc solutions. Like old generators, automatic generators were considered safe for medical purpose. (Author) [pt

  14. Biolimus-eluting biodegradable polymer-coated stent versus durable polymer-coated sirolimus-eluting stent in unselected patients receiving percutaneous coronary intervention (SORT OUT V)

    DEFF Research Database (Denmark)

    Christiansen, Evald Høj; Jensen, Lisette Okkels; Thayssen, Per

    2013-01-01

    Third-generation biodegradable polymer drug-eluting stents might reduce the risk of stent thrombosis compared with first-generation permanent polymer drug-eluting stents. We aimed to further investigate the effects of a biodegradable polymer biolimus-eluting stent compared with a durable polymer......-coated sirolimus-eluting stent in a population-based setting....

  15. Density Gradient Stabilization of Electron Temperature Gradient Driven Turbulence in a Spherical Tokamak

    International Nuclear Information System (INIS)

    Ren, Y.; Kaye, S.M.; Mazzucato, E.; Guttenfelder, W.; Bell, R.E.; Domier, C.W.; LeBlanc, B.P.; Lee, K.C.; Luhmann, N.C. Jr.; Smith, D.R.; Yuh, H.

    2011-01-01

    In this letter we report the first clear experimental observation of density gradient stabilization of electron temperature gradient driven turbulence in a fusion plasma. It is observed that longer wavelength modes, k (perpendicular) ρ s ∼< 10, are most stabilized by density gradient, and the stabilization is accompanied by about a factor of two decrease in the plasma effective thermal diffusivity.

  16. Functional Nanoarchitectures For Enhanced Drug Eluting Stents

    Science.gov (United States)

    Saleh, Yomna E.; Gepreel, Mohamed A.; Allam, Nageh K.

    2017-01-01

    Different strategies have been investigated to allow for optimum duration and conditions for endothelium healing through the enhancement of coronary stents. In this study, a nanoarchitectured system is proposed as a surface modification for drug eluting stents. Highly oriented nanotubes were vertically grown on the surface of a new Ni-free biocompatible Ti-based alloy, as a potential material for self-expandable stents. The fabricated nanotubes were self-grown from the potential stent substrate, which are also proposed to enhance endothelial proliferation while acting as drug reservoir to hinder Vascular Smooth Muscle Cells (VSMC) proliferation. Two morphologies were synthesized to investigate the effect of structure homogeneity on the intended application. The material was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Nanoindentation technique was used to study the mechanical properties of the fabricated material. Cytotoxicity and proliferation studies were performed and compared for the two fabricated nanoarchitectures, versus smooth untextured samples, using in-vitro cultured endothelial cells. Finally, the drug loading capacity was experimentally studied and further supported by computational modeling of the release profile.

  17. Irradiance gradients

    International Nuclear Information System (INIS)

    Ward, G.J.; Heckbert, P.S.; Technische Hogeschool Delft

    1992-04-01

    A new method for improving the accuracy of a diffuse interreflection calculation is introduced in a ray tracing context. The information from a hemispherical sampling of the luminous environment is interpreted in a new way to predict the change in irradiance as a function of position and surface orientation. The additional computation involved is modest and the benefit is substantial. An improved interpolation of irradiance resulting from the gradient calculation produces smoother, more accurate renderings. This result is achieved through better utilization of ray samples rather than additional samples or alternate sampling strategies. Thus, the technique is applicable to a variety of global illumination algorithms that use hemicubes or Monte Carlo sampling techniques

  18. Production and setting of fractional elution facility for recovery of useful rare metals from seawater

    International Nuclear Information System (INIS)

    Seko, Noriaki; Kasai, Noboru; Tamada, Masao; Hasegawa, Shin; Katakai, Akio

    2005-01-01

    In September 1999, we have soaked 200 kg of fibrous amidoxime absorbents, synthesized by radiation-induced graft polymerization, into seawater to evaluate their performance. Fractional elution facility was set effectively to elute the rare metals on adsorbents in Mutsu-Establishment. This facility consists of two parts of pre-washing and elution. The present report dealt with planning, manufacture and setting of fractional facility. Marine organism and slime on adsorbent cassette (290 x 295 x 160 mm) were washed out and every 72 cassettes were set in elution unit (1210 x 1210 x H1460 mm) with nonwoven materials as a packing to avoid elution loss. In the elution process alkaline and alkaline earth metals were eluted with low concentration hydrochloric acid (0.01M) and rare metals were eluted with high concentration (0.5 M) after the packing of elution unit into fractional elution facility. Adsorbent cassettes were regenerated with alkaline solution after elution procedure. (author)

  19. COMPARISON OF GKS CALCULATED CRITICAL ION TEMPERATURE GRADIENTS AND ITG GROWTH RATES TO DIII-D MEASURED GRADIENTS AND DIFFUSIVITIES

    International Nuclear Information System (INIS)

    BAKER, DR; STAEBLER, GM; PETTY, CC; GREENFIELD, CM; LUCE, TC

    2003-01-01

    OAK-B135 The gyrokinetic equations predict that various drift type waves or modes can be unstable in a tokamak. For some of these modes, such as the ion temperature gradient (ITG) mode and the electron temperature gradient mode, there exists a critical gradient, above which the mode is unstable. Since the existence of unstable modes can cause increased transport, plasmas which are centrally heated tend to increase in temperature gradient until the modes become unstable. Under some conditions the increased transport can fix the gradient at the critical value. here they present a comparison between the measured ion temperature gradients and the critical gradient as calculated by a gyrokinetic linear stability (GKS) code. They also present the maximum linear growth rate as calculated by this code for comparison to experimentally derived transport coefficients. The results show that for low confinement mode (L-mode) discharges, the measured ion temperature gradient is significantly greater than the GKS calculated critical gradient over a large region of the plasma. This is the same region of the plasma where the ion thermal diffusivity is large. For high confinement mode (H-mode) discharges the ion temperature gradient is closer to the critical gradient, but often still greater than the critical gradient over some region. For the best H-mode discharges, the ion temperature is less than or equal to the critical gradient over the whole plasma. In general they find that the position in the plasma where the ion thermal diffusivity starts to increase rapidly is where the maximum linear growth rate is greater than the E x B shearing rate

  20. Evaluation on elution feature of bentonite buffer materials

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Hirohisa; Kanno, Takeshi; Matsumoto, Kazuhiro

    1997-09-01

    In order to evaluate long term physical stability of artificial barrier in land disposal of high level radioactive wastes, it is necessary to know quantitatively elution behavior of buffering materials from disposal road (or cavity) to circumferential rock crack. When elution of the buffer material occurs on large scale, amount of bentonite in the disposal road (or cavity) reduces and reduction of various functions expected to the buffer materials is presumed. According to specification examples of road transverse arrangement and disposal vertical arrangement systems, evaluation on elution amount of the buffer materials at disposal environment was conducted. Opening width of rock crack in the disposal environment was supposed to be 0.5 mm. As a result, obtained mass elution ratios of the buffer materials due to extrusion phenomenon were 0.04 to 0.2% after 10,000 year and 2 to 12% after 1,000,000 years. (G.K.)

  1. Characterization of CRUDE OILS and petroleum products: (i) elution ...

    African Journals Online (AJOL)

    Characterization of CRUDE OILS and petroleum products: (i) elution liquid chromatographic separation and gas chromatographic analysis of crude oils and petroleum products. E.O. Odebunmi, E.A. Ogunsakin, P.E.P. Ilukhor ...

  2. Kuldkaru elutöö eest / Endel Link

    Index Scriptorium Estoniae

    Link, Endel

    2001-01-01

    Ameerika näitleja Kirk Douglas (1916), kellele seekordsel Berlinalel antakse elutöö eest Kuldkaru. Austamisõhtul näidatakse teda Stanley Kubricku kaua keelu all olnud filmis "Tee kuulsusele " ("Paths of Glory") : 1957

  3. Nickel elution properties of contemporary interatrial shunt closure devices.

    Science.gov (United States)

    Verma, Divya Ratan; Khan, Muhammad F; Tandar, Anwar; Rajasekaran, Namakkal S; Neuharth, Renée; Patel, Amit N; Muhlestein, Joseph B; Badger, Rodney S

    2015-02-01

    We sought to compare nickel elution properties of contemporary interatrial shunt closure devices in vitro. There are two United States Food and Drug Administration (FDA)-approved devices for percutaneous closure of secundum atrial septal defect: the Amplatzer septal occluder (ASO; St Jude Medical Corporation) and Gore Helex septal occluder (HSO; W.L. Gore & Associates). The new Gore septal occluder (GSO) device is in clinical trials. These are also used off-label for patent foramen ovale closure in highly selected patients. These devices have high nickel content. Nickel allergy is the most common reason for surgical device explantation. Nickel elution properties of contemporary devices remain unknown. We compared nickel elution properties of 4 devices - ASO, GSO, HSO, and sternal wire (SW) - while Dulbecco's phosphate-buffered saline (DPBS) served as control. Three samples of each device were submerged in DPBS. Nickel content was measured at 14 intervals over 90 days. Nickel elution at 24 hours, compared to control (0.005 ± 0.0 mg/L), was significantly higher for ASO (2.98 ± 1.65 mg/L; P=.04) and SW (0.03 ± 0.014 mg/L; P=.03). Nickel levels at 90 days, compared to control (0.005 ± 0.0 mg/L) and adjusting for multiple comparisons, were significantly higher for ASO (19.80 ± 2.30 mg/L; P=.01) and similar for HSO (P=.34), GSO (P=.34), and SW (P=.34). ASO had significantly higher nickel elution compared to HSO, GSO, and SW (P=.01). There is substantial variability in nickel elution; devices with less exposed nickel (HSO and GSO) have minimal elution. The safety of low nickel elution devices in patients with nickel allergy needs to be evaluated in prospective trials.

  4. pH-zone-refining elution-extrusion countercurrent chromatography: Separation of hydroxyanthraquinones from Cassiae semen.

    Science.gov (United States)

    Bu, Zhisi; Lv, Liqiong; Li, Xingnuo; Chu, Chu; Tong, Shengqiang

    2017-11-01

    Seven hydroxyanthraquinones were successfully separated from the traditional Chinese medicinal herb Cassiae semen by conventional and pH-zone-refining countercurrent chromatography with an environmentally friendly biphasic solvent system, in which elution-extrusion mode was investigated for pH-zone-refining countercurrent chromatography for the first time. A two-phase solvent system composed of n-hexane/ethyl acetate/ethanol/water (5:3:4:4, v/v/v/v) was used for the conventional countercurrent chromatography while the same system with a different volume ratio n-hexane/ethyl acetate/ethanol/water (3:5:2:6, v/v/v/v) was used for pH-zone-refining countercurrent chromatography, in which 20 mmol/L of trifluoroacetic acid was added in the organic phase as a retainer and 15 mmol/L of ammonia was added to the aqueous phase as an eluter. A 400 mg crude sample could be well separated by pH-zone-refining countercurrent chromatography, yielding 53 mg of aurantio-obtusin, 40 mg of chryso-obtusin, 18 mg of obtusin, 24 mg of obtusifolin, 10 mg of emodin, and 105 mg of the mixture of chrysophanol and physcion with a purity of over 95.8, 95.7, 96.9, 93.5, 97.4, 77.1, and 19.8%, as determined by high-performance liquid chromatography. Furthermore, the difference in elution sequence between conventional and pH-zone-refining mode was observed and discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Microinstabilities in weak density gradient tokamak systems

    International Nuclear Information System (INIS)

    Tang, W.M.; Rewoldt, G.; Chen, L.

    1986-04-01

    A prominent characteristic of auxiliary-heated tokamak discharges which exhibit improved (''H-mode type'') confinement properties is that their density profiles tend to be much flatter over most of the plasma radius. Depsite this favorable trend, it is emphasized here that, even in the limit of zero density gradient, low-frequency microinstabilities can persist due to the nonzero temperature gradient

  6. Determination of organoarsenic species in marine samples using gradient elution cation exchange HPLC-ICP-MS

    DEFF Research Database (Denmark)

    Sloth, Jens Jørgen; Larsen, Erik Huusfeldt; Julshamn, Kåre

    2003-01-01

    and dimethylarsinoylacetic acid, whereas the cationic arsenocholine ion and tetramethylarsonium ion were not affected. The accuracy of the method for DMA, AsB and TMAs was validated with the CRMs DORM-2 and BCR626 Tuna. The concentrations found for arsenobetaine, dimethylarsinic acid and tetramethylarsonium ion were within...

  7. Unfolding and aggregation of a glycosylated monoclonal antibody on a cation exchange column. Part I. Chromatographic elution and batch adsorption behavior.

    Science.gov (United States)

    Guo, Jing; Zhang, Shaojie; Carta, Giorgio

    2014-08-22

    A glycosylated IgG2 monoclonal antibody exhibits a two-peak elution behavior when loaded on a strong cation exchange column and eluted with either a linear salt gradient or two salt steps at increasing salt concentrations. The two-peak behavior is more pronounced for conditions where the initial antibody binding is stronger, i.e. at lower pH and buffer concentration, where the hold time prior to elution is longer, where the protein mass load is lower, and where the load flow rate is higher. The effect is also dependent on the resin type, being prominent for the polymer-functionalized resin Fractogel EMD SO₃(-) and virtually absent for a macroporous resin with similar backbone but no grafted polymers. Size exclusion chromatography and dynamic light scattering show that the early eluting peak consists exclusively of the native monomeric species while the late eluting peak is a mixture of monomeric and aggregated species. Batch adsorption/desorption experiments show that the bound protein can be desorbed in two steps, with a fraction desorbed in 0.33 M NaCl, corresponding to native monomer, and a second fraction desorbed in 1M NaCl. The latter fraction decreases with protein mass load and becomes almost negligible when the resin is initially completely saturated with protein. Confocal laser scanning microscopy showed that the two-peak elution/desorption behavior is related to the unique kinetics of protein binding in the Fractogel resin. Following partial loading of the resin, the bound protein migrates toward the center of the particles during a hold step and is redistributed across the particle volume attaining low local bound protein concentrations. For these conditions the protein is apparently destabilized forming a strongly-bound unfolded intermediate that, in turn, generates aggregates upon elution in high salt. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Investigation of the elution by seawater of caesium and strontium from loaded clinoptilolite

    International Nuclear Information System (INIS)

    Harder, B.R.; Mitchell, I.H.; Smyth, M.J.

    1985-07-01

    Simple investigations of the elution of caesium and strontium from loaded clinoptilolite are described. The clinoptilolite was loaded to levels expected in the British Nuclear Fuels plc SIXEP plant and contacted with seawater at approx. 15 C. (The elution time was measured until about 99% of the caesium and strontium had been eluted.) It was found that 99% of the caesium was eluted in 35 hours but the strontium (with more variable results) took at least 400 hours for 99% elution. (author)

  9. Efficacy and safety of zotarolimus-eluting and sirolimus-eluting coronary stents in routine clinical care (SORT OUT III): a randomised controlled superiority trial

    DEFF Research Database (Denmark)

    Rasmussen, Klaus; Maeng, Michael; Kaltoft, Anne

    2010-01-01

    In low-risk patients, the zotarolimus-eluting stent has been shown to reduce rates of restenosis without increasing the risk of stent thrombosis. We compared the efficacy and safety of the zotarolimus-eluting stent versus the sirolimus-eluting stent in patients with coronary artery disease who we...

  10. Ion temperature gradient instability

    International Nuclear Information System (INIS)

    1989-01-01

    Anomalous ion thermal conductivity remains an open physics issue for the present generation of high temperature Tokamaks. It is generally believed to be due to Ion Temperature Gradient Instability (η i mode). However, it has been difficult, if not impossible to identify this instability and study the anomalous transport due to it, directly. Therefore the production and identification of the mode is pursued in the simpler and experimentally convenient configuration of the Columbia Linear Machine (CLM). CLM is a steady state machine which already has all the appropriate parameters, except η i . This parameter is being increased to the appropriate value of the order of 1 by 'feathering' a tungsten screen located between the plasma source and the experimental cell to flatten the density profile and appropriate redesign of heating antennas to steepen the ion temperature profile. Once the instability is produced and identified, a thorough study of the characteristics of the mode can be done via a wide range of variation of all the critical parameters: η i , parallel wavelength, etc

  11. Destabilization of drift waves due to nonuniform density gradient

    International Nuclear Information System (INIS)

    Hirose, A.; Ishihara, O.

    1985-01-01

    It is shown that the conventional mode differential equation for low frequency electrostatic waves in a tokamak does not contain full ion dynamics. Both electrons and ions contribute to the ballooning term, which is subject to finite ion Larmor radius effects. Also, both fluid ion approximation and kinetic ion model yield the same correction. Reexamined are the density gradient universal mode and ion temperature gradient instability employing the lowest order Pearlstein-Berk type radial eigenfunctions. No unstable, bounded, energy outgoing eigenfunctions have been found. In particular, a large ion temperature gradient (eta/sub i/) tends to further stabilize the temperature gradient driven mode

  12. Current manufacturing processes of drug-eluting sutures.

    Science.gov (United States)

    Champeau, Mathilde; Thomassin, Jean-Michel; Tassaing, Thierry; Jérôme, Christine

    2017-11-01

    Drug-eluting sutures represent the next generation of surgical sutures since they fulfill their mechanical functions but also deliver the drug in their vicinity after implantation. These implants are produced by a variety of manufacturing processes. Drug-eluting sutures represent the next generation of surgical sutures since they fulfill their mechanical functions but also deliver the drug in their vicinity after implantation. These implants are produced by a variety of manufacturing processes. Two general approaches can be followed: (i) the ones that add the API into the material during the manufacturing process of the suture and (ii) the ones that load the API to an already manufactured suture. Areas covered: This review provides an overview of the current manufacturing processes for drug-eluting suture production and discusses their benefits and drawbacks depending on the type of drugs. The mechanical properties and the drug delivery profile of drug-eluting sutures are highlighted since these implants must fulfill both criteria. Expert opinion: For limited drug contents, melt extrusion and electrospinning are the emerging processes since the drug is added during the suture manufacture process. Advantageously, the drug release profile can be tuned by controlling the processing parameters specific to each process and the composition of the drug-containing polymer. If high drug content is targeted, the coating or grafting of a drug layer on a pre-manufactured suture allows for preservation of the tensile strength requirements of the suture.

  13. Development of a pheromone elution rate physical model

    Science.gov (United States)

    M.E. Teske; H.W. Thistle; B.L. Strom; H. Zhu

    2015-01-01

    A first principle modeling approach has been applied to available data describing the elution of semiochemicals from pheromone dispensers. These data included field data for 27 products developed by several manufacturers, including homemade devices, as well as environmental chamber data collected on three semiochemical products. The goal of this effort was to...

  14. Sirolimus-eluting versus bare-metal stent implantation in patients with ostial lesions

    DEFF Research Database (Denmark)

    Jørgensen, Erik; Kelbæk, Henning; Kløvgaard, Lene

    2010-01-01

    To investigate the efficacy of implantation of sirolimus-eluting stents (SES) in the ostium of coronary arteries.......To investigate the efficacy of implantation of sirolimus-eluting stents (SES) in the ostium of coronary arteries....

  15. A prospective, randomized evaluation of a novel everolimus-eluting coronary stent

    DEFF Research Database (Denmark)

    Stone, Gregg W; Teirstein, Paul S; Meredith, Ian T

    2011-01-01

    We sought to evaluate the clinical outcomes with a novel platinum chromium everolimus-eluting stent (PtCr-EES) compared with a predicate cobalt chromium everolimus-eluting stent (CoCr-EES) in patients undergoing percutaneous coronary intervention (PCI).......We sought to evaluate the clinical outcomes with a novel platinum chromium everolimus-eluting stent (PtCr-EES) compared with a predicate cobalt chromium everolimus-eluting stent (CoCr-EES) in patients undergoing percutaneous coronary intervention (PCI)....

  16. Coreless Concept for High Gradient Induction Cell

    International Nuclear Information System (INIS)

    Krasnykh, Anatoly

    2008-01-01

    An induction linac cell for a high gradient is discussed. The proposed solid state coreless approach for the induction linac topology (SLIM(reg s ign)) is based on nanosecond mode operation. This mode may have an acceleration gradient comparable with gradients of rf- accelerator structures. The discussed induction system has the high electric efficiency. The key elements are a solid state semiconductor switch and a high electric density dielectric with a thin section length. The energy in the induction system is storied in the magnetic field. The nanosecond current break-up produces the high voltage. The induced voltage is used for acceleration. This manner of an operation allows the use of low voltage elements in the booster part and achieves a high accelerating gradient. The proposed topology was tested in POP (proof of principle) experiments

  17. From drug eluting stents to bioresorbable scaffolds; to new horizons in PCI

    NARCIS (Netherlands)

    Tenekecioglu, Erhan; Bourantas, Christos; Abdelghani, Mohammad; Zeng, Yaping; Silva, Rafael Cavalcante; Tateishi, Hiroki; Sotomi, Yohei; Onuma, Yoshinobu; Yılmaz, Mustafa; Serruys, Patrick W.

    2016-01-01

    Drug eluting stents and particularly the fully bioresorbable drug-eluting scaffolds herald a new era in percutaneous treatment of coronary artery disease. There has been tremendous progress in drug eluting stents with fully biodegradable coating polymers and polymer-free devices with reservoir

  18. Comparison of Durable-Polymer Zotarolimus-Eluting and Biodegradable-Polymer Biolimus-Eluting Coronary Stents in Patients With Coronary Artery Disease

    DEFF Research Database (Denmark)

    Raungaard, Bent; Christiansen, Evald H; Bøtker, Hans Erik

    2017-01-01

    artery disease or acute coronary syndromes and at least 1 coronary artery lesion requiring treatment with a drug-eluting stent. Endpoints included major adverse cardiac events (MACE), a composite of safety (cardiac death and myocardial infarction not clearly attributable to a non-target lesion......OBJECTIVES: The authors sought to compare the safety and efficacy of the biocompatible durable-polymer zotarolimus-eluting stent with the biodegradable-polymer biolimus-eluting stent in unselected coronary patients. BACKGROUND: Biodegradable-polymer biolimus-eluting stents are superior to first......-generation durable-polymer drug-eluting stents in long-term randomized all-comer trials. Long-term data comparing them to second-generation durable-polymer drug-eluting stents are lacking. METHODS: The study was a randomized, multicenter, all-comer, noninferiority trial in patients with chronic stable coronary...

  19. Differential clinical outcomes after 1 year versus 5 years in a randomised comparison of zotarolimus-eluting and sirolimus-eluting coronary stents (the SORT OUT III study)

    DEFF Research Database (Denmark)

    Maeng, Michael; Tilsted, Hans Henrik; Jensen, Lisette Okkels

    2014-01-01

    received two different types of drug-eluting stents. METHODS: We undertook this multicentre, open-label, randomised superiority trial at five percutaneous coronary intervention centres in Denmark. We randomly allocated 2332 eligible adult patients (≥18 years of age) with an indication for drug......-eluting stent implantation to the zotarolimus-eluting Endeavor Sprint stent (Medtronic, Santa Rosa, CA, USA) or the sirolimus-eluting Cypher Select Plus stent (Cordis, Johnson & Johnson, Warren, NJ, USA). Randomisation of participants was achieved by computer-generated block randomisation and a telephone...

  20. [Drug-eluting stent thrombosis and its pharmacological prevention].

    Science.gov (United States)

    Pershukov, I V; Batyraliev, T A

    2007-01-01

    The problem of drug eluting stents (DES) safety has been actively discussed throughout 2006 because of increase of frequency of development of late stent thromboses which were noted during almost 2 years after stenting. In December 2006 US Food and Drug Administration (FDA) advisory panel acknowledged increase of development of late stent thrombosis. At the same time FDA accepted new definition of stent-thrombosis suggested by the Academic Research Consortium. According to this definition thrombosis can be definite, probable and possible. Any unexplained death before end of follow-up in a trial should be considered thrombosis related. Recalculation of thrombosis rate using this definition caused pronounced increase of this parameter in previously conducted trials. Thrombosis rate rose from 0,6 to 3,3% for bare metal stents, from 0,8 to 3,6% for sirolimus eluting stents and from 1,3 to 3,5% for paclitaxel eluting stents. Professional cardiological and angiographical societies (ACC, AHA, SCAI) responding to FDA advisory panel published their proofs and vision of the problem of stent thrombosis. In February 2007 ACC, AHA, SCAI, American College of Surgeons and Association of Dentists published scientific bulletin in which described preventive measures aimed at lowering of risk of thrombosis development. This document contains strict recommendation to continue double antithrombotic therapy with aspirin and clopidogrel for 12 months after implantation of DES or abandonment of the use of this type of stents when long term double antithrombotic therapy is not possible.

  1. Enhancing cognate target elution efficiency in gel-free chemical proteomics

    Directory of Open Access Journals (Sweden)

    Branka Radic-Sarikas

    2015-12-01

    Full Text Available Gel-free liquid chromatography mass spectrometry coupled to chemical proteomics is a powerful approach for characterizing cellular target profiles of small molecules. We have previously described a fast and efficient elution protocol; however, altered target profiles were observed. We hypothesised that elution conditions critically impact the effectiveness of disrupting drug-protein interactions. Thus, a number of elution conditions were systematically assessed with the aim of improving the recovery of all classes of proteins whilst maintaining compatibility with immunoblotting procedures. A double elution with formic acid combined with urea emerged as the most efficient and generically applicable elution method for chemical proteomics

  2. Retention modeling under organic modifier gradient conditions in ion-pair reversed-phase chromatography. Application to the separation of a set of underivatized amino acids.

    Science.gov (United States)

    Pappa-Louisi, A; Agrafiotou, P; Papachristos, K

    2010-07-01

    The combined effect of the ion-pairing reagent concentration, C(ipr), and organic modifier content, phi, on the retention under phi-gradient conditions at different constant C(ipr) was treated in this study by using two approaches. In the first approach, the prediction of the retention time of a sample solute is based on a direct fitting procedure of a proper retention model to 3-D phi-gradient retention data obtained under the same phi-linear variation but with different slope and time duration of the initial isocratic part and in the presence of various constant C(ipr) values in the eluent. The second approach is based on a retention model describing the combined effect of C(ipr) and phi on the retention of solutes in isocratic mode and consequently analyzes isocratic data obtained in mobile phases containing different C(ipr) values. The effectiveness of the above approaches was tested in the retention prediction of a mixture of 16 underivatized amino acids using mobile phases containing acetonitrile as organic modifier and sodium dodecyl sulfate as ion-pairing reagent. From these approaches, only the first one gives satisfactory predictions and can be successfully used in optimization of ion-pair chromatographic separations under gradient conditions. The failure of the second approach to predict the retention of solutes in the gradient elution mode in the presence of different C(ipr) values was attributed to slow changes in the distribution equilibrium of ion-pairing reagents caused by phi-variation.

  3. Comparison of an everolimus-eluting bioresorbable scaffold with an everolimus-eluting metallic stent for the treatment of coronary artery stenosis (ABSORB II)

    DEFF Research Database (Denmark)

    Serruys, Patrick W; Chevalier, Bernard; Sotomi, Yohei

    2016-01-01

    BACKGROUND: No medium-term data are available on the random comparison between everolimus-eluting bioresorbable vascular scaffolds and everolimus-eluting metallic stents. The study aims to demonstrate two mechanistic properties of the bioresorbable scaffold: increase in luminal dimensions as a re...

  4. Effect of Post-Dilatation Following Primary PCI With Everolimus-Eluting Bioresorbable Scaffold Versus Everolimus-Eluting Metallic Stent Implantation

    DEFF Research Database (Denmark)

    Yamaji, Kyohei; Brugaletta, Salvatore; Sabaté, Manel

    2017-01-01

    OBJECTIVES: This study sought to investigate the effect of post-dilatation on angiographic and intracoronary imaging parameters in the setting of primary percutaneous coronary intervention comparing the everolimus-eluting bioresorbable scaffold (BRS) with the everolimus-eluting metallic stent (EE...

  5. Zotarolimus-eluting durable-polymer-coated stent versus a biolimus-eluting biodegradable-polymer-coated stent in unselected patients undergoing percutaneous coronary intervention (SORT OUT VI)

    DEFF Research Database (Denmark)

    Raungaard, Bent; Jensen, Lisette Okkels; Tilsted, Hans-Henrik

    2015-01-01

    BACKGROUND: New-generation drug-eluting coronary stents have reduced the risk of coronary events, especially in patients with complex disease or lesions. To what extent different stent platforms, polymers, and antiproliferative drugs affect outcomes, however, is unclear. We investigated the safety...... and efficacy of a third-generation stent by comparing a highly biocompatible durable-polymer-coated zotarolimus-eluting stent with a biodegradable-polymer-coated biolimus-eluting stent. METHODS: This open-label, randomised, multicentre, non-inferiority trial was done at three sites across western Denmark. All......-polymer zotarolimus-eluting stent or the biodegradable-polymer biolimus-eluting stent. The primary endpoint was a composite of safety (cardiac death and myocardial infarction not clearly attributable to a non-target lesion) and efficacy (target-lesion revascularisation) at 12 months, analysed by intention to treat...

  6. Biodegradable-Polymer Biolimus-Eluting Stents versus Durable-Polymer Everolimus-Eluting Stents at One-Year Follow-Up: A Registry-Based Cohort Study.

    Science.gov (United States)

    Parsa, Ehsan; Saroukhani, Sepideh; Majlessi, Fereshteh; Poorhosseini, Hamidreza; Lofti-Tokaldany, Masoumeh; Jalali, Arash; Salarifar, Mojtaba; Nematipour, Ebrahim; Alidoosti, Mohammad; Aghajani, Hassan; Amirzadegan, Alireza; Kassaian, Seyed Ebrahim

    2016-04-01

    We compared outcomes of percutaneous coronary intervention patients who received biodegradable-polymer biolimus-eluting stents with those who received durable-polymer everolimus-eluting stents. At Tehran Heart Center, we performed a retrospective analysis of the data from January 2007 through December 2011 on 3,270 consecutive patients with coronary artery disease who underwent percutaneous coronary intervention with the biodegradable-polymer biolimus-eluting stent or the durable-polymer everolimus-eluting stent. We excluded patients with histories of coronary artery bypass grafting or percutaneous coronary intervention, acute ST-segment-elevation myocardial infarction, or the implantation of 2 different stent types. Patients were monitored for 12 months. The primary endpoint was a major adverse cardiac event, defined as a composite of death, nonfatal myocardial infarction, and target-vessel and target-lesion revascularization. Durable-polymer everolimus-eluting stents were implanted in 2,648 (81%) and biodegradable-polymer biolimus-eluting stents in 622 (19%) of the study population. There was no significant difference between the 2 groups (2.7% vs 2.7%; P=0.984) in the incidence of major adverse cardiac events. The cumulative adjusted probability of major adverse cardiac events in the biodegradable-polymer biolimus-eluting stent group did not differ from that of such events in the durable-polymer everolimus-eluting stent group (hazard ratio=0.768; 95% confidence interval, 0.421-1.44; P=0.388). We conclude that in our patients the biodegradable-polymer biolimus-eluting stent was as effective and safe, during the 12-month follow-up period, as was the durable-polymer everolimus-eluting stent.

  7. Optimization of Drug Delivery by Drug-Eluting Stents.

    Directory of Open Access Journals (Sweden)

    Franz Bozsak

    Full Text Available Drug-eluting stents (DES, which release anti-proliferative drugs into the arterial wall in a controlled manner, have drastically reduced the rate of in-stent restenosis and revolutionized the treatment of atherosclerosis. However, late stent thrombosis remains a safety concern in DES, mainly due to delayed healing of the endothelial wound inflicted during DES implantation. We present a framework to optimize DES design such that restenosis is inhibited without affecting the endothelial healing process. To this end, we have developed a computational model of fluid flow and drug transport in stented arteries and have used this model to establish a metric for quantifying DES performance. The model takes into account the multi-layered structure of the arterial wall and incorporates a reversible binding model to describe drug interaction with the cells of the arterial wall. The model is coupled to a novel optimization algorithm that allows identification of optimal DES designs. We show that optimizing the period of drug release from DES and the initial drug concentration within the coating has a drastic effect on DES performance. Paclitaxel-eluting stents perform optimally by releasing their drug either very rapidly (within a few hours or very slowly (over periods of several months up to one year at concentrations considerably lower than current DES. In contrast, sirolimus-eluting stents perform optimally only when drug release is slow. The results offer explanations for recent trends in the development of DES and demonstrate the potential for large improvements in DES design relative to the current state of commercial devices.

  8. Studies of post-elution concentration of 99m-Tc eluted from a gel type chromatographic generator

    International Nuclear Information System (INIS)

    Suzuki, Katia N.; Osso Junior, Joao Alberto

    2007-01-01

    The radiopharmaceuticals most used in Diagnostic Nuclear Medicine are those labeled with the metastable technetium ( 99m Tc) due to its ideal physical properties of decay (t 1/2 6.01 h, Eγ 140 keV), low cost and availability facilitated through the commercial generator 99 Mo / 99m Tc. This radionuclide is formed by the β - decay of 99 Mo adsorbed on an alumina column of the generator and collected in the form of sodium pertechnetate (Na 99m TcO 4 ) by elution with saline solution (0.9%). The Radiopharmacy Center (CR) of the IPEN-CNEN/SP developed a gel type chromatographic generator of MoZr with 99 Mo produced by 98 Mo(n, γ) 99 Mo reaction that occurs in IEA-R1 Nuclear Reactor. The gel is composed of zirconium molybdate with elution volume of 12 ml with an activity of 11100 MBq (300 mCi) producing a radioactive concentration of 925 MBq (34 mCi) / ml. The fission generator gives a higher radioactive concentration around 1850 MBq (69 mCi) / ml. The aim of this work is to study a system of post-elution concentration using ion exchange cartridges in tandem (cation - anion) for the attainment of a high enough radioactive concentration to meet the demand of market, with a proved quality. This system of concentration will be made based in the technique of solid phase extraction (SPE) using commercial cartridges of extraction, which contains the solid phase and eluent saline solution (0.9%). As the eluent results of this system used in the gel generator of MoZr will be compared with the fission generator currently produced by IPEN-CNEN/SP. (author)

  9. Studies of post-elution concentration of {sup 99m}-Tc eluted from a gel type chromatographic generator

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Katia N.; Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: norisuzuki6@yahoo.com.br; jaosso@ipen.br

    2007-07-01

    The radiopharmaceuticals most used in Diagnostic Nuclear Medicine are those labeled with the metastable technetium ({sup 99m}Tc) due to its ideal physical properties of decay (t{sub 1/2} 6.01 h, E{gamma} 140 keV), low cost and availability facilitated through the commercial generator {sup 99}Mo /{sup 99m}Tc. This radionuclide is formed by the {beta}{sup -} decay of {sup 99}Mo adsorbed on an alumina column of the generator and collected in the form of sodium pertechnetate (Na{sup 99m}TcO{sub 4}) by elution with saline solution (0.9%). The Radiopharmacy Center (CR) of the IPEN-CNEN/SP developed a gel type chromatographic generator of MoZr with {sup 99}Mo produced by {sup 98}Mo(n, {gamma}){sup 99}Mo reaction that occurs in IEA-R1 Nuclear Reactor. The gel is composed of zirconium molybdate with elution volume of 12 ml with an activity of 11100 MBq (300 mCi) producing a radioactive concentration of 925 MBq (34 mCi) / ml. The fission generator gives a higher radioactive concentration around 1850 MBq (69 mCi) / ml. The aim of this work is to study a system of post-elution concentration using ion exchange cartridges in tandem (cation - anion) for the attainment of a high enough radioactive concentration to meet the demand of market, with a proved quality. This system of concentration will be made based in the technique of solid phase extraction (SPE) using commercial cartridges of extraction, which contains the solid phase and eluent saline solution (0.9%). As the eluent results of this system used in the gel generator of MoZr will be compared with the fission generator currently produced by IPEN-CNEN/SP. (author)

  10. Safety and efficacy of limus-eluting stents and balloon angioplasty for sirolimus-eluting in-stent restenosis

    Energy Technology Data Exchange (ETDEWEB)

    Ota, Hideaki [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Mahmoudi, Michael [University of Surrey, Guildford Road, Surrey, GU2-7XH (United Kingdom); Kitabata, Hironori; Torguson, Rebecca; Chen, Fang; Satler, Lowell F.; Suddath, William O.; Pichard, Augusto D. [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Waksman, Ron, E-mail: ron.waksman@medstar.net [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States)

    2015-03-15

    Objectives: The aim of this study was to compare the safety and efficacy of everolimus-eluting stent (EES), sirolimus-eluting stent (SES), and plain old balloon angioplasty (POBA) for the treatment of SES in-stent restenosis (S-ISR). Background: The optimal treatment for drug-eluting in-stent restenosis remains controversial. Methods: The study cohort comprised 310 consecutive patients (444 lesions) who presented with S-ISR to our institution and underwent treatment with EES (43 patients), SES (102), or POBA (165). The analyzed clinical parameters were the 1-year rates of death, Q-wave myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), definite stent thrombosis (ST) and major adverse cardiac event (MACE) defined as the composite of death, MI, or TLR at 1-year. Results: The three groups were well matched for the conventional risk factors for coronary artery disease except for smoking. The 1-year analyzed clinical parameters were similar in the three groups: MACE (EES = 14%, SES = 18%, POBA = 20%; p = 0.65), death (EES = 2.3%, SES = 6.2%, POBA = 6.1%; p = 0.61), MI (EES = 4.8%, SES = 2.1%, POBA = 2.5%; p = 0.69), TLR (EES = 11.9%, SES = 12.1%, POBA = 24%; p = 0.78), and TVR (EES = 11.9%, SES = 24.8%, POBA = 22.2%; p = 0.23). There were no cases of definite ST. MACE-free rate was significantly lower in patients with recurrent in-stent restenosis (log-rank p = 0.006). Presentation with acute MI, number of treated lesions and a previous history of MI were found to be independent predictors of MACE. Conclusions: In patients presenting with S-ISR, treatment with implantation of an EES, SES, or POBA is associated with similar clinical outcomes. Patients presenting with recurrent ISR may have a poorer clinical outcome.

  11. On fracture in finite strain gradient plasticity

    DEFF Research Database (Denmark)

    Martínez Pañeda, Emilio; Niordson, Christian Frithiof

    2016-01-01

    In this work a general framework for damage and fracture assessment including the effect of strain gradients is provided. Both mechanism-based and phenomenological strain gradient plasticity (SGP) theories are implemented numerically using finite deformation theory and crack tip fields are invest......In this work a general framework for damage and fracture assessment including the effect of strain gradients is provided. Both mechanism-based and phenomenological strain gradient plasticity (SGP) theories are implemented numerically using finite deformation theory and crack tip fields...... are investigated. Differences and similarities between the two approaches within continuum SGP modeling are highlighted and discussed. Local strain hardening promoted by geometrically necessary dislocations (GNDs) in the vicinity of the crack leads to much higher stresses, relative to classical plasticity...... in the multiple parameter version of the phenomenological SGP theory. Since this also dominates the mechanics of indentation testing, results suggest that length parameters characteristic of mode I fracture should be inferred from nanoindentation....

  12. Advantages and disadvantages of biodegradable platforms in drug eluting stents.

    Science.gov (United States)

    Rodriguez-Granillo, Agustina; Rubilar, Bibiana; Rodriguez-Granillo, Gaston; Rodriguez, Alfredo E

    2011-03-26

    Coronary angioplasty with drug-eluting stent (DES) implantation is currently the most common stent procedure worldwide. Since the introduction of DES, coronary restenosis as well as the incidence of target vessel and target lesion revascularization have been significantly reduced. However, the incidence of very late stent thrombosis beyond the first year after stent deployment has more commonly been linked to DES than to bare-metal stent (BMS) implantation. Several factors have been associated with very late stent thrombosis after DES implantation, such as delayed healing, inflammation, stent mal-apposition and endothelial dysfunction. Some of these adverse events were associated with the presence of durable polymers, which were essential to allow the elution of the immunosuppressive drug in the first DES designs. The introduction of erodable polymers in DES technology has provided the potential to complete the degradation of the polymer simultaneously or immediately after the release of the immunosuppressive drug, after which a BMS remains in place. Several DES designs with biodegradable (BIO) polymers have been introduced in preclinical and clinical studies, including randomized trials. In this review, we analyze the clinical results from 6 observational and randomized studies with BIO polymers and discuss advantages and disadvantages of this new technology.

  13. Transarterial chemoembolization with drug-eluting beads in hepatocellular carcinoma

    Science.gov (United States)

    Nam, Hee Chul; Jang, Bohyun; Song, Myeong Jun

    2016-01-01

    Transarterial chemoembolization (TACE) is a widely used standard treatment for patients with hepatocellular carcinoma (HCC) who are not suitable candidates for curative treatments. The rationale for TACE is that intra-arterial chemotherapy using lipiodol and chemotherapeutic agents, followed by selective vascular embolization, results in a strong cytotoxic effect as well as ischemia (conventional TACE). Recently, drug-eluting beads (DC Beads®) have been developed for transcatheter treatment of HCC to deliver higher doses of the chemotherapeutic agent and to prolong contact time with the tumor. DC Beads® can actively sequester doxorubicin hydrochloride from solution and release it in a controlled sustained fashion. Treatment with DC Beads® substantially reduced the amount of chemotherapeutic agent that reached the systemic circulation compared with conventional, lipiodol-based regimens, significantly reducing drug-related adverse events. In this article, we describe the treatment response, survival, and safety of TACE used with drug-eluting beads for the treatment of HCC and discuss future therapeutic possibilities. PMID:27833376

  14. Dynamics of silver elution from functionalised antimicrobial nanofiltration membranes.

    Science.gov (United States)

    Choudhari, S; Habimana, O; Hannon, J; Allen, A; Cummins, E; Casey, E

    2017-07-01

    In an effort to mitigate biofouling on thin film composite membranes such as nanofiltration and reverse osmosis, a myriad of different surface modification strategies has been published. The use of silver nanoparticles (Ag-NPs) has emerged as being particularly promising. Nevertheless, the stability of these surface modifications is still poorly understood, particularly under permeate flux conditions. Leaching or elution of Ag-NPs from the membrane surface can not only affect the antimicrobial characteristics of the membrane, but could also potentially present an environmental liability when applied in industrial-scale systems. This study sought to investigate the dynamics of silver elution and the bactericidal effect of an Ag-NP functionalised NF270 membrane. Inductively coupled plasma-atomic emission spectroscopy was used to show that the bulk of leached silver occurred at the start of experimental runs, and was found to be independent of salt or permeate conditions used. Cumulative amounts of leached silver did, however, stabilise following the initial release, and were shown to have maintained the biocidal characteristics of the modified membrane, as observed by a higher fraction of structurally damaged Pseudomonas fluorescens cells. These results highlight the need to comprehensively assess the time-dependent nature of bactericidal membranes.

  15. Recent developments in drug eluting devices with tailored interfacial properties.

    Science.gov (United States)

    Sanchez-Rexach, Eva; Meaurio, Emilio; Sarasua, Jose-Ramon

    2017-11-01

    Drug eluting devices have greatly evolved during past years to become fundamental products of great marketing importance in the biomedical field. There is currently a large diversity of highly specialized devices for specific applications, making the development of these devices an exciting field of research. The replacement of the former bare metal devices by devices loaded with drugs allowed the sustained and controlled release of drugs, to achieve the desired local therapeutic concentration of drug. The newer devices have been "engineered" with surfaces containing micro- and nanoscale features in a well-controlled manner, that have shown to significantly affect cellular and subcellular function of various biological systems. For example, the topography can be structured to form an antifouling surface mimicking the defense mechanisms found in nature, like the skin of the shark. In the case of bone implants, well-controlled nanostructured interfaces can promote osteoblast differentiation and matrix production, and enhance short-term and long-term osteointegration. In any case, the goal of current research is to design implants that induce controlled, guided, and rapid healing. This article reviews recent trends in the development of drug eluting devices, as well as recent developments on the micro/nanotechnology scales, and their future challenges. For this purpose medical devices have been divided according to the different systems of the body they are focused to: orthopedic devices, breathing stents, gastrointestinal and urinary systems, devices for cardiovascular diseases, neuronal implants, and wound dressings. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Elution of monomer from different bulk fill dental composite resins.

    Science.gov (United States)

    Cebe, Mehmet Ata; Cebe, Fatma; Cengiz, Mehmet Fatih; Cetin, Ali Rıza; Arpag, Osman Fatih; Ozturk, Bora

    2015-07-01

    The purpose of this study was to evaluate the elution of Bis-GMA, TEGDMA, HEMA, and Bis-EMA monomers from six bulk fill composite resins over four different time periods, using HPLC. Six different composite resin materials were used in the present study: Tetric Evo Ceram Bulk Fill (Ivoclar Vivadent, Amherst, NY), X-tra Fill (VOCO, Cuxhaven, Germany), Sonic Fill (Kerr, Orange, CA, USA), Filtek Bulk Fill (3M ESPE Dental Product, St. Paul, MN), SDR (Dentsply, Konstanz, Germany), EQUIA (GC America INC, Alsip, IL). The samples (4mm thickness, 5mm diameter) were prepared and polymerized for 20s with a light emitted diode unit. After fabrication, each sample was immediately immersed in 75wt% ethanol/water solution used as extraction fluid and stored in the amber colored bottles at room temperature. Ethanol/water samples were taken (0.5mL) at predefined time intervals:10m (T1), 1h (T2), 24h (T3) and 30 days (T4). These samples were analyzed by HPLC. The obtained data were analyzed with one-way ANOVA and Tukey HSD at significance level of pcomposites (pcomposite resins in all time periods and the amount of eluted monomers was increased with time. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Theoretical aspects of gradient reversed-phase high performance liquid chromatography of styrene-butylacrylate block copolymers

    NARCIS (Netherlands)

    Kolarova, L.; Jandera, P.; Vonk, E.C.; Claessens, H.A.

    2004-01-01

    Butylacrylate – styrene co-polymers prepared by atom transfer radical polymeratization were separated on an octadecyl silica column by gradient elution with tetrahydrofuran in water, up to the molar masses 10,000. In reversed-phase high performance liquid chromatography (RP-HPLC), the retention of

  18. Intimal hyperplasia and vascular remodeling after everolimus-eluting and sirolimus-eluting stent implantation in diabetic patients the randomized diabetes and drug-eluting stent (DiabeDES) IV intravascular ultrasound trial

    DEFF Research Database (Denmark)

    Antonsen, Lisbeth; Maeng, Michael; Thayssen, Per

    2013-01-01

    OBJECTIVE: To evaluate the effects of the everolimus-eluting Xience™/Promus™ stent (EES) and the sirolimus-eluting Cypher™ stent (SES) on intimal hyperplasia (IH) in diabetic patients. BACKGROUND: Patients with diabetes mellitus have increased risk of in-stent restenosis after coronary stent...... implantation due to intimal hyperplasia (IH). METHODS: In a sub study of the Randomized Comparison of Everolimus-Eluting and Sirolimus-Eluting Stents in Patients Treated with Percutaneous Coronary Intervention (SORT OUT IV trial), serial intravascular ultrasound (IVUS) 10-month follow-up data were available...... in 88 patients, including 48 EES and 40 SES treated patients. IVUS endpoints included IH volume, in-stent % volume obstruction and changes in external elastic membrane (EEM) volume. RESULTS: Compared with the SES group, IH volume was increased in the EES group [median (interquartile range): 2.8 mm(3) (0...

  19. Theory and applications of a novel ion exchange chromatographic technology using controlled pH gradients for separating proteins on anionic and cationic stationary phases.

    Science.gov (United States)

    Tsonev, Latchezar I; Hirsh, Allen G

    2008-07-25

    pISep is a major new advance in low ionic strength ion exchange chromatography. It enables the formation of externally controlled pH gradients over the very broad pH range from 2 to 12. The gradients can be generated on either cationic or anionic exchangers over arbitrary pH ranges wherein the stationary phases remain totally charged. Associated pISep software makes possible the calculation of either linear, nonlinear or combined, multi-step, multi-slope pH gradients. These highly reproducible pH gradients, while separating proteins and glycoproteins in the order of their electrophoretic pIs, provide superior chromatographic resolution compared to salt. This paper also presents a statistical mechanical model for protein binding to ion exchange stationary phases enhancing the electrostatic interaction theory for the general dependence of retention factor k, on both salt and pH simultaneously. It is shown that the retention factors computed from short time isocratic salt elution data of a model protein can be used to accurately predict its salt elution concentration in varying slope salt elution gradients formed at varying isocratic pH as well as the pH at which it will be eluted from an anionic exchange column by a pISep pH gradient in the absence of salt.

  20. Late lumen loss and intima hyperplasia after sirolimus-eluting and zotarolimus-eluting stent implantation in diabetic patients: the diabetes and drug-eluting stent (DiabeDES III) angiography and intravascular ultrasound trial

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Mæng, Michael; Thayssen, Per

    2011-01-01

    Patients with diabetes mellitus have increased risk of in-stent restenosis after coronary stent implantation due to neointimal hyperplasia (NIH). The aim of this study was to use quantitative coronary angiography (QCA) and volumetric intravascular ultrasound (IVUS) to evaluate the effects...... of the sirolimus-eluting Cypher® stent (SES) and the zotarolimus-eluting Endeavor® stent (ZES) on angiographic late lumen loss and intima hyperplasia in diabetic patients....

  1. The stenting strategy of drug-eluting stents for coronary artery disease in patients on dialysis

    Directory of Open Access Journals (Sweden)

    Hiroshi Fujita

    2014-12-01

    Full Text Available Background: Reports regarding the relationship between the length and diameter of implanted drug-eluting stents and clinical and angiographic outcomes in dialysis patients are limited. Aim: We investigated the efficiency of drug-eluting stents for coronary artery disease in patients on dialysis from the viewpoint of stent sizing. Methods: Sirolimus-eluting stents were implanted in 88 lesions and bare metal stents were implanted in 43 lesions. We compared stenting strategy, major adverse cardiac events, and angiographic results between sirolimus-eluting stent and bare metal stent groups. Results: Stent diameter was smaller and stent length was longer in the sirolimus-eluting stent group than in the bare metal stent group in our routine practices. There was no significant between-group difference in late diameter loss. Rates of angiographic restenosis and target lesion revascularization were significantly higher in the sirolimus-eluting stent group than in the bare metal stent group. Although stent length was significantly longer and stent diameter was smaller in the sirolimus-eluting stent group, sirolimus-eluting stents did not improve the subsequent clinical and angiographic results compared with bare metal stents in dialysis patients. Conclusion: In dialysis patients, a longer length and/or smaller diameter sirolimus-eluting stent implantation was associated with high rates of restenosis and target lesion revascularization compared with bare metal stents.

  2. $L_{0}$ Gradient Projection.

    Science.gov (United States)

    Ono, Shunsuke

    2017-04-01

    Minimizing L 0 gradient, the number of the non-zero gradients of an image, together with a quadratic data-fidelity to an input image has been recognized as a powerful edge-preserving filtering method. However, the L 0 gradient minimization has an inherent difficulty: a user-given parameter controlling the degree of flatness does not have a physical meaning since the parameter just balances the relative importance of the L 0 gradient term to the quadratic data-fidelity term. As a result, the setting of the parameter is a troublesome work in the L 0 gradient minimization. To circumvent the difficulty, we propose a new edge-preserving filtering method with a novel use of the L 0 gradient. Our method is formulated as the minimization of the quadratic data-fidelity subject to the hard constraint that the L 0 gradient is less than a user-given parameter α . This strategy is much more intuitive than the L 0 gradient minimization because the parameter α has a clear meaning: the L 0 gradient value of the output image itself, so that one can directly impose a desired degree of flatness by α . We also provide an efficient algorithm based on the so-called alternating direction method of multipliers for computing an approximate solution of the nonconvex problem, where we decompose it into two subproblems and derive closed-form solutions to them. The advantages of our method are demonstrated through extensive experiments.

  3. Considerations of ion temperature gradient driven turbulence

    International Nuclear Information System (INIS)

    Cowley, S.C.; Kulsrud, R.M.

    1991-02-01

    The ion temperature gradient driven instability is considered in this paper. Physical pictures are presented to clarify the nature of the instability. The saturation of a single eddy is modeled by a simple nonlinear equation. We show that eddies which are elongated in the direction of the temperature gradient are the most unstable and have the highest saturation amplitudes. In a sheared magnetic field, such elongated eddies twist with the field lines. This structure is shown to be alternative to the usual Fourier mode picture in which the mode is localized around the surface where k parallel = 0. We show how these elongated twisting eddies, which are an integral part of the ''ballooning mode'' structure, could survive in a torus. The elongated eddies are shown to be unstable to secondary instabilities that are driven by the large gradients in the long eddy. We argue that this mechanism isotropizes ion temperature gradient turbulence. We further argue that the ''mixing length'' is set by this nonlinear process, not by a linear eigenmode width. 17 refs., 6 figs

  4. Drug diffusion and biological responses of arteries using a drug-eluting stent with nonuniform coating

    Directory of Open Access Journals (Sweden)

    Saito N

    2016-03-01

    Full Text Available Noboru Saito, Yuhei Mori, Sayaka Uchiyama Terumo Corporation R&D Center, Inokuchi, Nakai-machi, Ashigarakami-gun, Kanagawa, Japan Abstract: The purpose of this study was to determine the effect of a nonuniform coating, abluminal-gradient coating (AGC, which leaves the abluminal surface of the curves and links parts of the stent free from the drug coating, on the diffusion direction of the drug and the biological responses of the artery to drug-eluting stent (DES by comparing the AGC-sirolimus stent and the conventional full-surface coating (CFC sirolimus stent. The study aimed to verify whether the AGC approach was appropriate for the development of a safer DES, minimizing the risks of stent thrombosis due to delayed endothelialization by the drug and distal embolization due to cracking of the coating layer on the hinge parts of the DES on stent expansion. In the in vitro local drug diffusion study, we used rhodamine B as a model drug, and rhodamine B released from the AGC stent diffused predominantly into the abluminal side of the alginate artery model. Conversely, rhodamine B released from the CFC stent quickly spread to the luminal side of the artery model, where endothelial cell regeneration is required. In the biological responses study, the luminal surface of the iliac artery implanted with the AGC-sirolimus stent in a rabbit iliac artery for 2 weeks was completely covered with endothelial-like cells. On the other hand, the luminal surface of the iliac artery implanted with the CFC-sirolimus stent for 2 weeks only showed partial coverage with endothelial-like cells. While thrombosis was observed in two of the three CFC-sirolimus stents, it was observed in only one of the three AGC-sirolimus stents. Taken together, these findings indicate that the designed nonuniform coating (AGC is an appropriate approach to ensure a safer DES. However, the number of studies is limited and a larger study should be conducted to reach a statistically

  5. Determinants of protein elution rates from preparative ion-exchange adsorbents.

    Science.gov (United States)

    Angelo, James M; Lenhoff, Abraham M

    2016-04-01

    The rate processes involved in elution in preparative chromatography can affect both peak resolution and hence selectivity as well as practical factors such as facility fit. These processes depend on the physical structure of the adsorbent particles, the amount of bound solute, the solution conditions for operation or some combination of these factors. Ion-exchange adsorbents modified with covalently attached or grafted polymer layers have become widely used in preparative chromatography. Their often easily accessible microstructures offer substantial binding capacities for biomolecules, but elution has sometimes been observed to be undesirably slow. In order to determine which physicochemical phenomena control elution behavior, commercially available cellulosic, dextran-grafted and unmodified agarose materials were characterized here by their elution profiles at various conditions, including different degrees of loading. Elution data were analyzed under the assumption of purely diffusion-limited control, including the role of pore structure properties such as porosity and tortuosity. In general, effective elution rates decreased with the reduction of accessible pore volume, but differences among different proteins indicated the roles of additional factors. Additional measurements and analysis, including the use of confocal laser scanning microscopy to observe elution within single chromatographic particles, indicated the importance of protein association within the particle during elution. The use of protein stabilizing agents was explored in systems presenting atypical elution behavior, and l-arginine and disaccharide excipients were shown to alleviate the effects for one protein, lysozyme, in the presence of sodium chloride. Incorporation of these excipients into eluent buffer gave rise to faster elution and significantly lower pool volumes in elution from polymer-modified adsorbents. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. 2-year clinical outcomes after implantation of sirolimus-eluting, paclitaxel-eluting, and bare-metal coronary stents: results from the WDHR (Western Denmark Heart Registry)

    DEFF Research Database (Denmark)

    Kaltoft, Anne; Jensen, Lisette Okkels; Maeng, Michael

    2009-01-01

    OBJECTIVES: This registry study assessed the safety and efficacy of the 2 types of drug-eluting stents (DES), sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES), compared with bare-metal stents (BMS). BACKGROUND: Drug-eluting stents may increase the risk of stent thrombosis (ST...... databases. We used Cox regression analysis to control for confounding. RESULTS: The 2-year incidence of definite ST was 0.64% in BMS patients, 0.79% in DES patients (adjusted relative risk [RR]: 1.09; 95% confidence interval [CI]: 0.72 to 1.65), 0.50% in SES patients (adjusted RR: 0.63, 95% CI: 0.35 to 1...

  7. Development of DNA elution method to detect irradiated foodstuff

    International Nuclear Information System (INIS)

    Copin, M.P.; Bourgeois, C.M.

    1991-01-01

    The aim of the work is to develop a reliable method to detect whether a fresh and frozen foodstuff has been irradiated. The molecule of DNA is one of the targets of ionizing radiation. The induction of three major classes of lesion have been shown. Double strand breaks, single strand breaks and base damage. Among the different techniques used to observe and quantify the strand breaks, techniques of elution are very interesting. The method proposed consisted of a filtration of the DNA at the atmospheric pressure and in non denaturing conditions. The amount of DNA retained on the filter is measured after being suitably labelled by microfluorometry. A difference in the amount of DNA retained on a filter of 2 μm from a lysed muscular tissue sample between a frozen Norway lobster which has been irradiated and one which has not, is observed. 7 refs

  8. Alkaline elution of uranium and molybdenum and their recovery

    International Nuclear Information System (INIS)

    Song Wenlan; Wu Peisheng; Zhao Pinzhi; Tao Dening; Xie Chaoyan

    1987-01-01

    The uranium and molybdenum can be simultaneously eluted by using eluant (NH 4 ) 2 CO 3 + (NH 4 ) 2 SO 4 from resin loaded uranium and molybdenum. The ADU is precipitated from eluant by volatilization of ammonia. The molybdenum is extracted by TFA-TBP-kerosene from the filtrate at pH 3.0-3.2 with molybdenum extraction > 98%. Uranium is nearly not extracted. The precipitation of Mo is reached by sulphuric acid after stripping and the ammonium multimolybdate is obtained. This process can give the total recovery more than 99% for U and 90% for Mo. Because of the use of sulphate salt system, the hazard of NO 3 - can be avoided

  9. Quantitation of radiolabeled compounds eluting from the HPLC system

    International Nuclear Information System (INIS)

    Kessler, M.J.

    1982-01-01

    Three techniques are compared for the quantitation of various radiolabeled compounds eluting in the high performance liquid chromatography system. The first technique requires fraction-collecting the effluent from the HPLC, removing an aliquot to scintillation vials, and counting each fraction in a liquid scintillation counter. The second uses direct interface of the HPLC effluent to a flow-through radioactivity detector. The third involves quantitation of various radiolabeled compounds (proteins, steroids, and nucleotides) by splitting the effluent from the HPLC with an electronic steam splitter, thus diverting a present portion to the fraction collector for further chemical characterization and the remainder to the radioactivity flow detector for direct quantitation. A direct comparison of the chromatograms and the radioactivity counting efficiencies of these three techniques is presented

  10. Drug-eluting stents to prevent stent thrombosis and restenosis.

    Science.gov (United States)

    Im, Eui; Hong, Myeong-Ki

    2016-01-01

    Although first-generation drug-eluting stents (DES) have significantly reduced the risk of in-stent restenosis, they have also increased the long-term risk of stent thrombosis. This safety concern directly triggered the development of new generation DES, with innovations in stent platforms, polymers, and anti-proliferative drugs. Stent platform materials have evolved from stainless steel to cobalt or platinum-chromium alloys with an improved strut design. Drug-carrying polymers have become biocompatible or biodegradable and even polymer-free DES were introduced. New limus-family drugs (such as everolimus, zotarolimus or biolimus) were adopted to enhance stent performances. As a result, these new DES demonstrated superior vascular healing responses on intracoronary imaging studies and lower stent thrombotic events in actual patients. Recently, fully-bioresorbable stents (scaffolds) have been introduced, and expanding their applications. In this article, the important concepts and clinical results of new generation DES and bioresorbable scaffolds are described.

  11. Development of an on-line mixed-mode gel liquid chromatography×reversed phase liquid chromatography method for separation of water extract from Flos Carthami.

    Science.gov (United States)

    Wang, Yu-Qing; Tang, Xu; Li, Jia-Fu; Wu, Yun-Long; Sun, Yu-Ying; Fang, Mei-Juan; Wu, Zhen; Wang, Xiu-Min; Qiu, Ying-Kun

    2017-10-13

    A novel on-line comprehensive two-dimensional liquid chromatography (2D-LC) method by coupling mixed-mode gel liquid chromatography (MMG-LC) with reversed phase liquid chromatography (RPLC) was developed. A mixture of 17 reference compounds was used to study the separation mechanism. A crude water extract of Flos Carthami was applied to evaluate the performance of the novel 2D-LC system. In the first dimension, the extract was eluted with a gradient of water/methanol over a cross-linked dextran gel Sephadex LH-20 column. Meanwhile, the advantages of size exclusion, reversed phase partition and adsorption separation mechanism were exploited before further on-line reversed phase purification on the second dimension. This novel on-line mixed-mode Sephadex LH-20×RPLC method provided higher peak resolution, sample processing ability (2.5mg) and better orthogonality (72.9%) versus RPLC×RPLC and hydrophilic interaction liquid chromatography (HILIC)×RPLC. To the best of our knowledge, this is the first report of a mixed-mode Sephadex LH-20×RPLC separation method with successful applications in on-line mode, which might be beneficial for harvesting targets from complicated medicinal plants. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Drug-eluting stents studies in mice: Do we need atherosclerosis to study restenosis?

    NARCIS (Netherlands)

    Pires, N.M.M.; Jukema, J.W.; Daemen, M.J.A.P.; Quax, P.H.A.

    2006-01-01

    In 2001, the first human study with drug-eluting stents (DES) was published showing a nearly complete abolition of restenosis by using a sirolimus-eluting stent. This success was very encouraging to test new compounds in combination with the DES platform. Nevertheless, several other anti-restenotic

  13. Possibility of obtaining enriched americium-242g by the elution of recoil atoms from zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Shafiev, A I; Vityutnev, V M; Ivanov, V M; Yakovlev, G N

    1974-12-31

    On the example of production the possibility of obtaining enriched actinide isotopes by the elution of recotl atoms with the use of a zeolite- americium-241 target was shown. The enrichment factor and the recoil atoms of / sup 242g/Am yield depend on preliminary target treatment and solution composition used for elution. (auth)

  14. Elution behavior of heavy metals from cement solidified products of incinerated ash waste - 59102

    International Nuclear Information System (INIS)

    Meguro, Yoshihiro; Kawato, Yoshimi; Nakayama, Takuya; Tomioka, Osamu; Mitsuda, Motoyuki

    2012-01-01

    A method, in which incinerated ash is solidified with a cement material, has been developed to dispose radioactive incinerated ash waste. In order to bury the solidified product, it is required that elution of hazardous heavy metals included in the ash from the solidified products is inhibited. In this study, the elution behavior of the heavy metals from the synthetic solidified products, which included Pb(II), Cd(II), and Cr(VI) and were prepared using ordinary portland cement (OPC), blast furnace slag cement (BFS), or a cement material that showed low alkalinity (LA-Cement), was investigated. Several chemicals and materials were added as additive agents to prevent the elution of the heavy metals. When OPC was used, Cd elution was inhibited, but Pb and Cr were not enough even using the additive agent examined. FeSO 4 and Na 2 S additive agents worked effective to inhibit elution of Cr. When BFS was used, the elution of Pb, Cd and Cr was inhibited for the all products prepared. In the case of LA-Cement, the elution of Pb and Cd was inhibited for the all products, but only the product that was added FeSO 4 showed good result of the elution of Cr. (authors)

  15. Cefoperazone and cefoperazone-sulbactam susceptibility tests with anaerobic bacteria by the thioglycolate disk elution method.

    OpenAIRE

    Barry, A L; Packer, R R; Jones, R N

    1985-01-01

    Tests were performed with 104 anaerobic microorganisms to evaluate the thioglycolate disk elution technique for the detection of resistance to cefoperazone and cefoperazone-sulbactam. An unacceptably high false-resistance rate and a poor reproducibility record make the disk elution procedure unsatisfactory for routine testing of this drug or combination of drugs.

  16. Patient-rated health status predicts prognosis following percutaneous coronary intervention with drug-eluting stenting

    DEFF Research Database (Denmark)

    Pedersen, Susanne S.; Versteeg, Henneke; Denollet, Johan

    2011-01-01

    In patients treated with percutaneous coronary intervention (PCI) with the paclitaxel-eluting stent, we examined whether patient-rated health status predicts adverse clinical events.......In patients treated with percutaneous coronary intervention (PCI) with the paclitaxel-eluting stent, we examined whether patient-rated health status predicts adverse clinical events....

  17. Ponderomotive force effects on temperature-gradient-driven instabilities

    International Nuclear Information System (INIS)

    Sundaram, A.K.; Hershkowitz, N.

    1992-01-01

    The modification of temperature-gradient-driven instabilities due to the presence of nonuniform radio-frequency fields near the ion cyclotron frequency is investigated in the linear regime. Employing the fluid theory, it is shown that the induced field line compression caused by ion cyclotron range of frequencies (ICRF) fields makes the net parallel compressibility positive, and thus provides a stabilizing influence on the ion-temperature-gradient-driven mode for an appropriately tailored profile of radio-frequency (rf) pressure. Concomitantly, the radial ponderomotive force generates an additional contribution via coupling between the perturbed fluid motion and the equilibrium ponderomotive force and this effect plays the role of dissipation to enhance or decrease the growth of temperature-gradient-driven modes depending upon the sign of rf pressure gradients. For decreased growth of temperature-gradient-driven instabilities, the plasma density gradients and rf pressure gradients must have opposite signs while enhancement in growth arises when both gradients have the same sign. Finally, the kinetic effects associated with these modes are briefly discussed

  18. Analysis of Biological Samples Using Paper Spray Mass Spectrometry: An Investigation of Impacts by the Substrates, Solvents and Elution Methods.

    Science.gov (United States)

    Ren, Yue; Wang, He; Liu, Jiangjiang; Zhang, Zhiping; McLuckey, Morgan N; Ouyang, Zheng

    2013-10-01

    Paper spray has been developed as a fast sampling ionization method for direct analysis of raw biological and chemical samples using mass spectrometry (MS). Quantitation of therapeutic drugs in blood samples at high accuracy has also been achieved using paper spray MS without traditional sample preparation or chromatographic separation. The paper spray ionization is a process integrated with a fast extraction of the analyte from the raw sample by a solvent, the transport of the extracted analytes on the paper, and a spray ionization at the tip of the paper substrate with a high voltage applied. In this study, the influence on the analytical performance by the solvent-substrate systems and the selection of the elution methods was investigated. The protein hemoglobin could be observed from fresh blood samples on silanized paper or from dried blood spots on silica-coated paper. The on-paper separation of the chemicals during the paper spray was characterized through the analysis of a mixture of the methyl violet 2B and methylene blue. The mode of applying the spray solvent was found to have a significant impact on the separation. The results in this study led to a better understanding of the analyte elution, on-paper separation, as well as the ionization processes of the paper spray. This study also help to establish a guideline for optimizing the analytical performance of paper spray for direct analysis of target analytes using mass spectrometry.

  19. Selective elution of HLA antigens and beta 2-microglobulin from human platelets by chloroquine diphosphate

    International Nuclear Information System (INIS)

    Kao, K.J.

    1988-01-01

    To determine whether chloroquine can specifically elute HLA antigens and beta 2-microglobulin (beta 2-M) from the platelet surface, quantitative immunofluorescence flow cytometry and monoclonal antibodies were used to show that HLA antigens and beta 2-M were proportionally eluted from the platelet surface without affecting the membrane glycoproteins IIb and IIIa. Second, an autoradiogram of electrophoresed I-125-labeled platelets showed that only beta 2-M but not other I-125-labeled membrane proteins could be eluted. Although HLA antigens were poorly labeled by I-125 and could not be detected on the autoradiogram, the eluted HLA antigens could be detected by anti-HLA monoclonal antibody and immunoblotting techniques. No loss of plasma membrane integrity was observed by transmission electron microscopy after chloroquine treatment of platelets. The results indicate that chloroquine selectively elutes HLA antigens and their noncovalently associated beta 2-M without affecting other integral platelet membrane proteins

  20. Long-Term Safety of Drug-Eluting and Bare-Metal Stents

    DEFF Research Database (Denmark)

    Palmerini, Tullio; Benedetto, Umberto; Biondi-Zoccai, Giuseppe

    2015-01-01

    BACKGROUND: Previous meta-analyses have investigated the relative safety and efficacy profiles of different types of drug-eluting stents (DES) and bare-metal stents (BMS); however, most prior trials in these meta-analyses reported follow-up to only 1 year, and as such, the relative long-term safety....... RESULTS: Fifty-one trials that included a total of 52,158 randomized patients with follow-up duration ≥3 years were analyzed. At a median follow-up of 3.8 years, cobalt-chromium everolimus-eluting stents (EES) were associated with lower rates of mortality, definite stent thrombosis (ST), and myocardial...... infarction than BMS, paclitaxel-eluting stents (PES), and sirolimus-eluting stents (SES) and less ST than BES. Phosphorylcholine-based zotarolimus-eluting stents had lower rates of definite ST than SES and lower rates of myocardial infarction than BMS and PES. The late rates of target...

  1. Travelling gradient thermocouple calibration

    International Nuclear Information System (INIS)

    Broomfield, G.H.

    1975-01-01

    A short discussion of the origins of the thermocouple EMF is used to re-introduce the idea that the Peltier and Thompson effects are indistinguishable from one another. Thermocouples may be viewed as devices which generate an EMF at junctions or as integrators of EMF's developed in thermal gradients. The thermal gradient view is considered the more appropriate, because of its better accord with theory and behaviour, the correct approach to calibration, and investigation of service effects is immediately obvious. Inhomogeneities arise in thermocouples during manufacture and in service. The results of travelling gradient measurements are used to show that such effects are revealed with a resolution which depends on the length of the gradient although they may be masked during simple immersion calibration. Proposed tests on thermocouples irradiated in a nuclear reactor are discussed

  2. Quaternion Gradient and Hessian

    OpenAIRE

    Xu, Dongpo; Mandic, Danilo P.

    2014-01-01

    The optimization of real scalar functions of quaternion variables, such as the mean square error or array output power, underpins many practical applications. Solutions typically require the calculation of the gradient and Hessian. However, real functions of quaternion variables are essentially nonanalytic, which are prohibitive to the development of quaternion-valued learning systems. To address this issue, we propose new definitions of quaternion gradient and Hessian, based on the novel gen...

  3. Mode-conversion process and overdense-plasma heating in the electron cyclotron range of frequencies

    International Nuclear Information System (INIS)

    Nakajima, S.; Abe, H.

    1988-01-01

    Through a particle-simulation investigation, a new mode-conversion process, through which an incident fast extraordinary mode (fast X mode) is converted into an electron Bernstein mode (B mode) via a (slow extraordinary mode slow X mode), is discovered in plasmas whose maximum density exceeds the cutoff density of the slow X mode. The converted B mode is found to heat the electrons efficiently in an overdense plasma region, when the plasma has the optimum density gradient at the plasma surface

  4. A sirolimus-eluting bioabsorbable polymer-coated stent (MiStent) versus an everolimus-eluting durable polymer stent (Xience) after percutaneous coronary intervention (DESSOLVE III): a randomised, single-blind, multicentre, non-inferiority, phase 3 trial

    NARCIS (Netherlands)

    de Winter, Robbert J.; Katagiri, Yuki; Asano, Taku; Milewski, Krzysztof P.; Lurz, Philipp; Buszman, Pawel; Jessurun, Gillian A. J.; Koch, Karel T.; Troquay, Roland P. T.; Hamer, Bas J. B.; Ophuis, Ton Oude; Wöhrle, Jochen; Wyderka, Rafał; Cayla, Guillaume; Hofma, Sjoerd H.; Levesque, Sébastien; Żurakowski, Aleksander; Fischer, Dieter; Kośmider, Maciej; Goube, Pascal; Arkenbout, E. Karin; Noutsias, Michel; Ferrari, Markus W.; Onuma, Yoshinobu; Wijns, William; Serruys, Patrick W.

    2018-01-01

    Background MiStent is a drug-eluting stent with a fully absorbable polymer coating containing and embedding a microcrystalline form of sirolimus into the vessel wall. It was developed to overcome the limitation of current durable polymer drug-eluting stents eluting amorphous sirolimus. The clinical

  5. Magnetoelectric Transverse Gradient Sensor with High Detection Sensitivity and Low Gradient Noise.

    Science.gov (United States)

    Zhang, Mingji; Or, Siu Wing

    2017-10-25

    We report, theoretically and experimentally, the realization of a high detection performance in a novel magnetoelectric (ME) transverse gradient sensor based on the large ME effect and the magnetic field gradient (MFG) technique in a pair of magnetically-biased, electrically-shielded, and mechanically-enclosed ME composites having a transverse orientation and an axial separation. The output voltage of the gradient sensor is directly obtained from the transverse MFG-induced difference in ME voltage between the two ME composites and is calibrated against transverse MFGs to give a high detection sensitivity of 0.4-30.6 V/(T/m), a strong common-mode magnetic field noise rejection rate of gradient noise of 0.16-620 nT/m/ Hz in a broad frequency range of 1 Hz-170 kHz under a small baseline of 35 mm. An analysis of experimental gradient noise spectra obtained in a magnetically-unshielded laboratory environment reveals the domination of the pink (1/ f ) noise, dielectric loss noise, and power-frequency noise below 3 kHz, in addition to the circuit noise above 3 kHz, in the gradient sensor. The high detection performance, together with the added merit of passive and direct ME conversion by the large ME effect in the ME composites, makes the gradient sensor suitable for the passive, direct, and broadband detection of transverse MFGs.

  6. Pressure gradient turbulent transport and collisionless reconnection

    International Nuclear Information System (INIS)

    Connor, J.W.

    1993-01-01

    The scale invariance technique is employed to discuss pressure gradient driven turbulent transport when an Ohm's law with electron inertia, rather than resistivity, is relevant. An expression for thermal diffusivity which has many features appropriate to L-mode transport in tokamaks, is seen to have greater generality than indicated by their particular calculation. The results of applying the technique to a more appropriate collisionless Ohm's law are discussed. (Author)

  7. Selective arsenic speciation analysis of human urine reference materials using gradient elution ion-exchange HPLC-ICP-MS

    DEFF Research Database (Denmark)

    Sloth, Jens Jørgen; Larsen, Erik Huusfeldt; Julshamn, K.

    2004-01-01

    identical with the reference values given for total arsenic. The obtained values for arsenobetaine and dimethylarsinic acid were identical with the values certified for the NIES No. 18 urine CRM. The speciation data presented here may be valuable for the quality assurance of analytical method development...

  8. Gradient Alloy for Optical Packaging

    Data.gov (United States)

    National Aeronautics and Space Administration — Advances in additive manufacturing, such as Laser Engineered Net Shaping (LENS), enables the fabrication of compositionally gradient microstructures, i.e. gradient...

  9. Confinement mechanisms in the radiatively improved mode

    NARCIS (Netherlands)

    Tokar, M. Z.; R. Jaspers,; Koslowski, H. R.; Kramer-Flecken, A.; Messiaen, A. M.; Ongena, J.; Rogister, A. A.; Unterberg, B.; Weynants, R. R.

    1999-01-01

    The characteristics of the toroidal ion temperature gradient (ITG) instability, considered as the main source of anomalous transport in the low (L) confinement mode of tokamaks, are analysed for the conditions of the radiatively improved (RI) mode triggered by seeding of impurities. Based on

  10. Towards enhanced automated elution systems for waterborne protozoa using megasonic energy.

    Science.gov (United States)

    Horton, B; Katzer, F; Desmulliez, M P Y; Bridle, H L

    2018-02-01

    Continuous and reliable monitoring of water sources for human consumption is imperative for public health. For protozoa, which cannot be multiplied efficiently in laboratory settings, concentration and recovery steps are key to a successful detection procedure. Recently, the use of megasonic energy was demonstrated to recover Cryptosporidium from commonly used water industry filtration procedures, forming thereby a basis for a simplified and cost effective method of elution of pathogens. In this article, we report the benefits of incorporating megasonic sonication into the current methodologies of Giardia duodenalis elution from an internationally approved filtration and elution system used within the water industry, the Filta-Max®. Megasonic energy assisted elution has many benefits over current methods since a smaller final volume of eluent allows removal of time-consuming centrifugation steps and reduces manual involvement resulting in a potentially more consistent and more cost-effective method. We also show that megasonic sonication of G. duodenalis cysts provides the option of a less damaging elution method compared to the standard Filta-Max® operation, although the elution from filter matrices is not currently fully optimised. A notable decrease in recovery of damaged cysts was observed in megasonic processed samples, potentially increasing the abilities of further genetic identification options upon isolation of the parasite from a filter sample. This work paves the way for the development of a fully automated and more cost-effective elution method of Giardia from water samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. An optimized method for elution of enteroviral RNA from a cellulose-based substrate.

    Science.gov (United States)

    Li, Yan; Yoshida, Hiromu; Wang, Lu; Tao, Zexin; Wang, Haiyan; Lin, Xiaojuan; Xu, Aiqiang

    2012-12-01

    The Flinders Technology Australia (FTA) Elute Card is a commercial product that facilitates the collection, transport, archiving and processing of nucleic acids from a wide variety of biological samples at room temperature. While the cards have been designed so that sterile/deionized water can elute DNA easily, they are not suitable for some less stable RNAs. This study was undertaken to determine the optimal conditions such as the buffer type, buffer pH and incubation temperature for the elution of enteroviral RNA from FTA Elute Cards prior to quantitative analysis using real-time PCR (qPCR) or consensus degenerate hybrid oligonucleotide primer VP1 RT-semi nested PCR (CODEHOP VP1 RT-snPCR). TE-1 (pH 8.0), rather than sterile water, was the best buffer for high efficiency elution of enteroviral RNA at 95°C. However, as the estimated recovery rate of viral RNA eluted from the cards averaged to be only 6.1%, enterovirus assays using FTA elution should be considered qualitative, especially at low virus titers, and therefore the results of the assay should be interpreted carefully. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Alkaline elution of DNA from mammalian cells on cellulose triacetate filters

    International Nuclear Information System (INIS)

    Moss, A.J. Jr.; Nagle, W.A.; Henle, K.J.; Prior, R.M.

    1984-01-01

    The alkaline elution technique is widely used for the estimation of cellular DNA damage because of its sensitivity in the biologically relevant dose range. The authors have extended the original studies and provide additional characterization of the cellulose triacetate alkaline elution method. This filter material permits the elution of approximately 80 percent of cellular DNA from untreated V79 cells. the total radioactivity in the system was compartmentalized with respect to 1) lysing solution, 2) washing solution, 3) elution fractions, and 4) membrane retained activity. In these studies [/sup 3/H]-thymidine labeled untreated internal control cells were co-eluted with X-irradiated [/sup 14/C]-thymidine labeled cells. For the estimation of DNA damage, elution profiles for treated cells were directly compared with untreated internal control cells. The quantity of DNA eluting in excess of the labeled internal control per fraction is directly proportional to the extent of DNA damage in the treated sample. Using the technique the necessity of an irradiated internal control is eliminated

  13. Towards Hypoxia-responsive Drug-eluting Embolization Beads.

    Science.gov (United States)

    Ashrafi, Koorosh; Heaysman, Clare L; Phillips, Gary J; Lloyd, Andrew W; Lewis, Andrew L

    2017-05-30

    Drug release from chemoembolization microspheres stimulated by the presence of a chemically reducing environment may provide benefits for targeting drug resistant and metastatic hypoxic tumours. A water-soluble disulfide-based bifunctional cross-linker bis(acryloyl)-(l)-cystine (BALC) was synthesised, characterised and incorporated into a modified poly(vinyl) alcohol (PVA) hydrogel beads at varying concentrations using reverse suspension polymerisation. The beads were characterised to confirm the amount of cross-linker within each formulation and its effects on the bead properties. Elemental and UV/visible spectroscopic analysis confirmed the incorporation of BALC within the beads and sizing studies showed that in the presence of a reducing agent, all bead formulations increased in mean diameter. The BALC beads could be loaded with doxorubicin hydrochloride and amounts in excess of 300mg of drug per mL of hydrated beads could be achieved but required conversion of the carboxylic acid groups of the BALC to their sodium carboxylate salt forms. Elution of doxorubicin from the beads demonstrated a controlled release via ionic exchange. Some formulations exhibited an increase in size and release of drug in the presence of a reducing agent, and therefore demonstrated the ability to respond to an in vitro reducing environment. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Bioresorbable polymer coated drug eluting stent: a model study.

    Science.gov (United States)

    Rossi, Filippo; Casalini, Tommaso; Raffa, Edoardo; Masi, Maurizio; Perale, Giuseppe

    2012-07-02

    In drug eluting stent technologies, an increased demand for better control, higher reliability, and enhanced performances of drug delivery systems emerged in the last years and thus offered the opportunity to introduce model-based approaches aimed to overcome the remarkable limits of trial-and-error methods. In this context a mathematical model was studied, based on detailed conservation equations and taking into account the main physical-chemical mechanisms involved in polymeric coating degradation, drug release, and restenosis inhibition. It allowed highlighting the interdependence between factors affecting each of these phenomena and, in particular, the influence of stent design parameters on drug antirestenotic efficacy. Therefore, the here-proposed model is aimed to simulate the diffusional release, for both in vitro and the in vivo conditions: results were verified against various literature data, confirming the reliability of the parameter estimation procedure. The hierarchical structure of this model also allows easily modifying the set of equations describing restenosis evolution to enhance model reliability and taking advantage of the deep understanding of physiological mechanisms governing the different stages of smooth muscle cell growth and proliferation. In addition, thanks to its simplicity and to the very low system requirements and central processing unit (CPU) time, our model allows obtaining immediate views of system behavior.

  15. Differentiated analysis of an everolimus-eluting stent and a paclitaxel-eluting stent among higher risk subgroups for restenosis: results from the SPIRIT II trial.

    Science.gov (United States)

    Khattab, Ahmed A; Richardt, Gert; Verin, Vitali; Kelbaek, Henning; Macaya, Carlos; Berland, Jacques; Miquel-Hebert, Karine; Dorange, Cécile; Serruys, Patrick W

    2008-03-01

    Restenosis is higher among certain subpopulations when subjected to percutaneous coronary interventions even when using drug-eluting stents. The randomised SPIRIT II trial demonstrated the superiority of the XIENCE V Everolimus Eluting Coronary Stent System over the TAXUS Paclitaxel-Eluting Stent System in terms of in-stent late loss at six months among 300 patients treated for de novo native coronary artery lesions. In this post-hoc analysis of SPIRIT II we focused on six-month angiographic outcomes of diabetic patients (n=69), left anterior descending arteries (n=149), long lesions >20 mm (n=43), small vessels B2 and C lesions (n=233). In-stent late loss was consistently less among all subgroups when treated by everolimus-eluting stents compared to paclitaxel-eluting stents: diabetics 0.15+/-0.26 mm versus 0.39+/-0.34 mm, p=0.006; LAD 0.12+/-0.23 mm versus 0.44+/-0.37 mm, pB2/C lesions 0.12+/-0.31 mm versus 0.36+/-0.36 mm, pSPIRIT II trial population.

  16. All-cause mortality after drug-eluting stent implantation in African-Americans.

    Science.gov (United States)

    Poludasu, Shyam; Cavusoglu, Erdal; Khan, Waqas; Marmur, Jonathan D

    2008-12-01

    Recent studies have questioned the safety of drug-eluting stents because of a higher incidence of late stent thrombosis, raising the possibility that drug-eluting stents may be associated with an increased mortality. The effect of drug-eluting stents on mortality in African-Americans is unknown. We evaluated 628 African-American patients (354 patients treated with drug-eluting stents and 274 patients treated with bare metal stents) between January 2003 and August 2005, using data from our bolus-only platelet glycoprotein IIb/IIIa inhibitor database. The primary end point was all-cause mortality obtained using social security death index. After a mean follow-up of 3+/-0.9 years, the mortality rate in the bare metal stents group was 12.8% compared with 7.1% in the drug-eluting stents group [adjusted P value=0.19; hazard ratio (HR) for bare metal stents group compared with drug-eluting stents group for death=1.4; 95% confidence interval (CI): 0.8-2.4]. In a subgroup analysis, patients presenting with acute coronary syndrome had a higher mortality when treated with bare metal stents compared with drug-eluting stents (17.1 vs. 6.3%, P=0.022; HR=2.2; 95% CI: 1.1-4.4). Patients with chronic kidney disease (all patients with creatinine >1.5 mg/dl) also had a higher mortality with bare metal stents compared with drug-eluting stents (36.7 vs. 20.4%, P=0.044; HR=2.3; 95% CI: 1.02-5.2). Drug-eluting stents seem to be safe in African-Americans and may improve survival in certain subgroups such as patients with acute coronary syndromes and chronic kidney disease.

  17. Porous Polymer Drug-Eluting Coating Prepared by Radiation Induced Polymerization

    International Nuclear Information System (INIS)

    Veres, M.; Tóth, S.; Koós, M.; Beiler, B.

    2009-01-01

    Drug-eluting stents have several advantages over bare metal implants. They eliminate restenosis, the main drawback of bare metal stents. In addition the locally delivered drug is more effective and causes less side-effects. However in some cases dangerous stent thrombosis, inflammatory and allergy reactions were observed after their implantation, which first of all related to the drug-eluting coating. This project is aimed to develop a novel biocompatible nanoporous polymer layer by radiation induced polymerization that is capable of holding and eluting drugs and promotes endothelization after the release of the drug. (author)

  18. Increasing flexibility in two-dimensional liquid chromatography by pulsed elution of the first dimension

    DEFF Research Database (Denmark)

    Jakobsen, Simon S.; Christensen, Jan H.; Verdier, Sylvain

    2017-01-01

    This work demonstrates the development of an online two-dimensional liquid chromatography (2D-LC) method where the first dimension column is eluted by a sequence of pulses of increasing eluotropic strength generated by the LC pumps (pulsed-elution 2D-LC). Between the pulses, the first dimension...... online comprehensive 2D-LC: undersampling, difficulties in refocusing, and lack of flexibility in the selection of column dimensions and flow rates because the two dimensions constrain each other. The pulsed-elution 2D-LC was applied for the analysis of a basic fraction of vacuum gas oil. Peak capacity...

  19. Porous Polymer Drug-Eluting Coating Prepared by Radiation Induced Polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Veres, M.; Tóth, S.; Koós, M. [Research Institute for Solid State Physics and Optics, Budapest (Hungary); Beiler, B. [Institute of Isotopes, HAS, Budapest (Hungary)

    2009-07-01

    Drug-eluting stents have several advantages over bare metal implants. They eliminate restenosis, the main drawback of bare metal stents. In addition the locally delivered drug is more effective and causes less side-effects. However in some cases dangerous stent thrombosis, inflammatory and allergy reactions were observed after their implantation, which first of all related to the drug-eluting coating. This project is aimed to develop a novel biocompatible nanoporous polymer layer by radiation induced polymerization that is capable of holding and eluting drugs and promotes endothelization after the release of the drug. (author)

  20. Tilting mode in field-reversed configurations

    International Nuclear Information System (INIS)

    Schwarzmeier, J.L.; Barnes, D.C.; Lewis, H.R.; Seyler, C.E.; Shestakov, A.I.

    1982-01-01

    Field Reversed Configurations (FRCs) experimentally have exhibited remarkable stability on the magnetohydrodynamic (MHD) timescale, despite numerous MHD calculations showing FRCs to be unstable. It is easy to believe that local modes are stabilized by finite Larmor radius (FLR) effects, but more puzzling is the apparent stability of FRCs against global modes, where one would expect FLR effects to be less important. In this paper we study the tilting mode, which MHD has shown to be a rapidly growing global mode. The tilting mode in FRCs is driven by the pressure gradient, and magnetic compression and field line bending are the stabilizing forces. A schematic of the evolution of the tilting mode is shown. The tilting mode is considered dangerous, because it would lead to rapid tearing across the separatrix. Unlike spheromaks, the tilting mode in FRCs has a separatrix that is fixed in space, so that the mode is strictly internal

  1. High Gradient Accelerator Research

    International Nuclear Information System (INIS)

    Temkin, Richard

    2016-01-01

    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  2. Efficacy and safety of zotarolimus-eluting and sirolimus-eluting coronary stents in routine clinical care (SORT OUT III): a randomised controlled superiority trial

    DEFF Research Database (Denmark)

    Rasmussen, Klaus; Maeng, Michael; Kaltoft, Anne

    2010-01-01

    BACKGROUND: In low-risk patients, the zotarolimus-eluting stent has been shown to reduce rates of restenosis without increasing the risk of stent thrombosis. We compared the efficacy and safety of the zotarolimus-eluting stent versus the sirolimus-eluting stent in patients with coronary artery...... disease who were receiving routine clinical care with no direct follow-up. METHODS: We did a single-blind, all-comer superiority trial in adult patients with chronic stable coronary artery disease or acute coronary syndromes, and at least one target lesion. Patients were treated at one of five...... Danish administrative and health-care registries. The primary endpoint was a composite of major adverse cardiac events within 9 months: cardiac death, myocardial infarction, and target vessel revascularisation. Intention-to-treat analyses were done at 9-month and 18-month follow-up. This trial...

  3. Randomised comparison of a bioresorbable everolimus-eluting scaffold with a metallic everolimus-eluting stent for ischaemic heart disease caused by de novo native coronary artery lesions

    DEFF Research Database (Denmark)

    Chevalier, Bernard; Onuma, Yoshinobu; van Boven, Ad J

    2016-01-01

    AIMS: The one-year randomised data of the ABSORB II trial showed that the everolimus-eluting bioresorbable scaffold and the everolimus-eluting metallic stent were comparable for the composite secondary clinical outcomes of patient-oriented composite endpoint (PoCE) and device-oriented composite...... Clara, CA, USA) or treatment with an everolimus-eluting metallic stent (XIENCE; Abbott Vascular). The trial enrolled 501 patients. Clinical follow-up at two years was available in 320 patients in the Absorb BVS arm and 160 patients in the XIENCE arm. At two years, the PoCE for the Absorb and XIENCE arms......-six percent and 34% of patients remained on DAPT at two years, respectively. Ninety-two percent of patients in both arms remained on aspirin. CONCLUSIONS: Two-year clinical results demonstrate sustained low rates of PoCE, MACE, DoCE and TVF with the Absorb BVS as compared to the XIENCE stent....

  4. Ponderomotive modification of drift tearing modes

    International Nuclear Information System (INIS)

    Urquijo, G.; Singh, R.; Sen, A.

    1997-01-01

    The linear characteristics of drift tearing modes are investigated in the presence of a significant background of radio-frequency (RF) waves in the ion cyclotron range of frequencies. The ponderomotive force, arising from the radial gradients in the RF field energy, is found to significantly modify the inner layer solutions of the drift tearing modes. It can have a stabilizing influence, even at moderate RF powers, provided the field energy has a decreasing radial profile at the mode rational surface. (author)

  5. Uniform gradient expansions

    CERN Document Server

    Giovannini, Massimo

    2015-01-01

    Cosmological singularities are often discussed by means of a gradient expansion that can also describe, during a quasi-de Sitter phase, the progressive suppression of curvature inhomogeneities. While the inflationary event horizon is being formed the two mentioned regimes coexist and a uniform expansion can be conceived and applied to the evolution of spatial gradients across the protoinflationary boundary. It is argued that conventional arguments addressing the preinflationary initial conditions are necessary but generally not sufficient to guarantee a homogeneous onset of the conventional inflationary stage.

  6. High gradient superconducting quadrupoles

    International Nuclear Information System (INIS)

    Lundy, R.A.; Brown, B.C.; Carson, J.A.; Fisk, H.E.; Hanft, R.H.; Mantsch, P.M.; McInturff, A.D.; Remsbottom, R.H.

    1987-07-01

    Prototype superconducting quadrupoles with a 5 cm aperture and gradient of 16 kG/cm have been built and tested as candidate magnets for the final focus at SLC. The magnets are made from NbTi Tevatron style cable with 10 inner and 14 outer turns per quadrant. Quench performance and multipole data are presented. Design and data for a low current, high gradient quadrupole, similar in cross section but wound with a cable consisting of five insulated conductors are also discussed

  7. Use of drug-eluting stents in Victorian public hospitals.

    Science.gov (United States)

    Yan, Bryan P; Ajani, Andrew E; Duffy, Stephen J; New, Gishel; Horrigan, Mark; Szto, Gregory; Walton, Antony; Eccleston, David; Lefkovits, Jeffery; Black, Alexander; Sebastian, Martin; Brennan, Angela L; Reid, Christopher M; Clark, David J

    2006-10-02

    We aimed to assess the pattern of use of drug-eluting stents (DESs) in patients undergoing percutaneous coronary interventions (PCIs) in Victorian public hospitals. Prospective study comparing the use of one or more DESs versus bare-metal stents (BMSs) only, in consecutive patients undergoing 2428 PCIs with stent implantation from 1 April 2004 to 31 December 2005 at seven Victorian public hospitals. Adherence to current Victorian Department of Human Services guidelines which recommend DES use in patients with high-risk features for restenosis (diabetes, small vessels, long lesions, in-stent restenotic lesions, chronic total occlusions and bifurcation lesions). Of the 2428 PCIs performed, at least one DES was implanted in 1101 (45.3%) and BMSs only were implanted in 1327 (54.7%). In 87.7% (966/1101) of PCI with DESs, there was at least one criterion for high risk of restenosis. DESs were more likely to be used in patients with diabetes (risk ratio [RR], 2.45; 95% CI, 2.02-2.97), small vessels (RR, 3.35; 95%CI, 2.35-4.76), long lesions (RR, 3.87; 95% CI, 3.23-4.65), in-stent restenotic lesions (RR, 3.98; 95%CI, 2.67-6.06), chronic total occlusions (RR, 1.30; 95% CI, 0.51-2.88) and bifurcation lesions (RR, 2.23; 95%CI, 1.57-3.17). However, 66.2% (1608/2428) of all PCIs were in patients eligible for DESs according to Victorian guidelines, and in 39.9% (642/1608) of these PCIs, a BMS was used. In Victorian public hospitals, DESs have been largely reserved for patients at high risk of restenosis in accordance with Department of Human Services guidelines. However, many patients with high-risk criteria for restenosis did not receive DESs. Greater use of DESs in these patients may improve outcomes by reducing the need for repeat revascularisation.

  8. Bicarbonate Elution of Uranium from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Horng-Bin [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Wai, Chien M. [Department of Chemistry, University of Idaho, Moscow, Idaho 83844 USA; Kuo, Li-Jung [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Gill, Gary [Pacific Northwest National Laboratory, Marine Sciences Laboratory, Sequim, Washington 98382 USA; Tian, Guoxin [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Rao, Linfeng [Lawrence Berkeley National Laboratory, Berkeley, California 94720 USA; Das, Sadananda [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Mayes, Richard T. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA; Janke, Christopher J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 USA

    2017-05-02

    Uranium adsorbed on amidoxime-based polyethylene fibers in simulated seawater can be quantitatively eluted using 3 M KHCO3 at 40°C. Thermodynamic calculations are in agreement with the experimental observation that at high bicarbonate concentrations (3 M) uranyl ions bound to amidoxime molecules are converted to uranyl tris-carbonato complex in the aqueous solution. The elution process is basically the reverse reaction of the uranium adsorption process which occurs at a very low bicarbonate concentration (~10-3 M) in seawater. In real seawater experiments, the bicarbonate elution is followed by a NaOH treatment to remove natural organic matter adsorbed on the polymer adsorbent. Using the sequential bicarbonate and NaOH elution, the adsorbent is reusable after rinsing with deionized water and the recycled adsorbent shows no loss of uranium loading capacity based on real seawater experiments.

  9. The application of PLC automatic control system for resin transfer in pulsed elution

    International Nuclear Information System (INIS)

    Long Maoxiong

    2001-01-01

    An application of Programmable Logic Controller (PLC) in automatic control system for resin transfer in pulsed elution column is described. The design principle as well as hardware and software are also described in detail

  10. Mechanisms of Very Late Drug-Eluting Stent Thrombosis Assessed by Optical Coherence Tomography

    DEFF Research Database (Denmark)

    Taniwaki, Masanori; Radu, Maria D; Zaugg, Serge

    2016-01-01

    BACKGROUND: The pathomechanisms underlying very late stent thrombosis (VLST) after implantation of drug-eluting stents (DES) are incompletely understood. Using optical coherence tomography, we investigated potential causes of this adverse event. METHODS AND RESULTS: Between August 2010 and Decemb...

  11. REUSABILITY OF BOND ELUT CERTIFY COLUMNS FOR THE EXTRACTION OF DRUGS FROM PLASMA

    NARCIS (Netherlands)

    CHEN, XH; FRANKE, JP; WIJSBEEK, J; DEZEEUW, RA

    1993-01-01

    The reusability of Bond Elut Certify columns for the extraction of toxicologically relevant drugs from plasma has been evaluated. Pentobarbital, hexobarbital, mepivacaine, trimipramine and clonazepam were selected as test drugs to represent various classes of drugs. The columns were regenerated

  12. Alendronate-Eluting Biphasic Calcium Phosphate (BCP Scaffolds Stimulate Osteogenic Differentiation

    Directory of Open Access Journals (Sweden)

    Sung Eun Kim

    2015-01-01

    Full Text Available Biphasic calcium phosphate (BCP scaffolds have been widely used in orthopedic and dental fields as osteoconductive bone substitutes. However, BCP scaffolds are not satisfactory for the stimulation of osteogenic differentiation and maturation. To enhance osteogenic differentiation, we prepared alendronate- (ALN- eluting BCP scaffolds. The coating of ALN on BCP scaffolds was confirmed by scanning electron microscopy (FE-SEM, energy-dispersive X-ray spectroscopy (EDS, and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR. An in vitro release study showed that release of ALN from ALN-eluting BCP scaffolds was sustained for up to 28 days. In vitro results revealed that MG-63 cells grown on ALN-eluting BCP scaffolds exhibited increased ALP activity and calcium deposition and upregulated gene expression of Runx2, ALP, OCN, and OPN compared with the BCP scaffold alone. Therefore, this study suggests that ALN-eluting BCP scaffolds have the potential to effectively stimulate osteogenic differentiation.

  13. Boron removal from aqueous solutions by ion-exchange resin: Column sorption-elution studies

    International Nuclear Information System (INIS)

    Koese, T. Ennil; Oztuerk, Nese

    2008-01-01

    A column sorption-elution study was carried out by using a strong base anion-exchange resin (Dowex 2 x 8) for the removal of boron from aqueous solutions. The breakthrough curve was obtained as a function of feed flow rate and the total and breakthrough capacity values of the resin were calculated. The boron on the resin was quantitatively eluted with 0.5 M HCl solution at different flow rates. Three consecutive sorption-elution-washing-regeneration-washing cycles were applied to the resin in order to investigate the reusability of the ion-exchange resin. Total capacity values remained almost the same after three sorption-elution-regeneration cycles. The Thomas and the Yoon-Nelson models were applied to experimental data to predict the breakthrough curves and to determine the characteristic column parameters required for process design. The results proved that the models would describe the breakthrough curves well

  14. Rapid analysis of charge variants of monoclonal antibodies using non-linear salt gradient in cation-exchange high performance liquid chromatography.

    Science.gov (United States)

    Joshi, Varsha; Kumar, Vijesh; Rathore, Anurag S

    2015-08-07

    A method is proposed for rapid development of a short, analytical cation exchange high performance liquid chromatography method for analysis of charge heterogeneity in monoclonal antibody products. The parameters investigated and optimized include pH, shape of elution gradient and length of the column. It is found that the most important parameter for development of a shorter method is the choice of the shape of elution gradient. In this paper, we propose a step by step approach to develop a non-linear sigmoidal shape gradient for analysis of charge heterogeneity for two different monoclonal antibody products. The use of this gradient not only decreases the run time of the method to 4min against the conventional method that takes more than 40min but also the resolution is retained. Superiority of the phosphate gradient over sodium chloride gradient for elution of mAbs is also observed. The method has been successfully evaluated for specificity, sensitivity, linearity, limit of detection, and limit of quantification. Application of this method as a potential at-line process analytical technology tool has been suggested. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Incorporating high-pressure electroosmotic pump and a nano-flow gradient generator into a miniaturized liquid chromatographic system for peptide analysis.

    Science.gov (United States)

    Chen, Apeng; Lynch, Kyle B; Wang, Xiaochun; Lu, Joann J; Gu, Congying; Liu, Shaorong

    2014-09-24

    We integrate a high-pressure electroosmotic pump (EOP), a nanoflow gradient generator, and a capillary column into a miniaturized liquid chromatographic system that can be directly coupled with a mass spectrometer for proteomic analysis. We have recently developed a low-cost high-pressure EOP capable of generating pressure of tens of thousands psi, ideal for uses in miniaturized HPLC. The pump worked smoothly when it was used for isocratic elutions. When it was used for gradient elutions, generating reproducible gradient profiles was challenging; because the pump rate fluctuated when the pump was used to pump high-content organic solvents. This presents an issue for separating proteins/peptides since high-content organic solvents are often utilized. In this work, we solve this problem by incorporating our high-pressure EOP with a nano-flow gradient generator so that the EOP needs only to pump an aqueous solution. With this combination, we develop a capillary-based nano-HPLC system capable of performing nano-flow gradient elution; the pump rate is stable, and the gradient profiles are reproducible and can be conveniently tuned. To demonstrate its utility, we couple it with either a UV absorbance detector or a mass spectrometer for peptide separations. Copyright © 2014. Published by Elsevier B.V.

  16. Plasma Modes

    Science.gov (United States)

    Dubin, D. H. E.

    This chapter explores several aspects of the linear electrostatic normal modes of oscillation for a single-species non-neutral plasma in a Penning trap. Linearized fluid equations of motion are developed, assuming the plasma is cold but collisionless, which allow derivation of the cold plasma dielectric tensor and the electrostatic wave equation. Upper hybrid and magnetized plasma waves in an infinite uniform plasma are described. The effect of the plasma surface in a bounded plasma system is considered, and the properties of surface plasma waves are characterized. The normal modes of a cylindrical plasma column are discussed, and finally, modes of spheroidal plasmas, and finite temperature effects on the modes, are briefly described.

  17. Development of an elution device for ViroCap virus filters.

    Science.gov (United States)

    Fagnant, Christine Susan; Toles, Matthew; Zhou, Nicolette Angela; Powell, Jacob; Adolphsen, John; Guan, Yifei; Ockerman, Byron; Shirai, Jeffry Hiroshi; Boyle, David S; Novosselov, Igor; Meschke, John Scott

    2017-10-19

    Environmental surveillance of waterborne pathogens is vital for monitoring the spread of diseases, and electropositive filters are frequently used for sampling wastewater and wastewater-impacted surface water. Viruses adsorbed to electropositive filters require elution prior to detection or quantification. Elution is typically facilitated by a peristaltic pump, although this requires a significant startup cost and does not include biosafety or cross-contamination considerations. These factors may pose a barrier for low-resource laboratories that aim to conduct environmental surveillance of viruses. The objective of this study was to develop a biologically enclosed, manually powered, low-cost device for effectively eluting from electropositive ViroCap™ virus filters. The elution device described here utilizes a non-electric bilge pump, instead of an electric peristaltic pump or a positive pressure vessel. The elution device also fully encloses liquids and aerosols that could contain biological organisms, thereby increasing biosafety. Moreover, all elution device components that are used in the biosafety cabinet are autoclavable, reducing cross-contamination potential. This device reduces costs of materials while maintaining convenience in terms of size and weight. With this new device, there is little sample volume loss due to device inefficiency, similar virus yields were demonstrated during seeded studies with poliovirus type 1, and the time to elute filters is similar to that required with the peristaltic pump. The efforts described here resulted in a novel, low-cost, manually powered elution device that can facilitate environmental surveillance of pathogens through effective virus recovery from ViroCap filters while maintaining the potential for adaptability to other cartridge filters.

  18. Manipulating the Gradient

    Science.gov (United States)

    Gaze, Eric C.

    2005-01-01

    We introduce a cooperative learning, group lab for a Calculus III course to facilitate comprehension of the gradient vector and directional derivative concepts. The lab is a hands-on experience allowing students to manipulate a tangent plane and empirically measure the effect of partial derivatives on the direction of optimal ascent. (Contains 7…

  19. Elution of lead from lead zirconate titanate ceramics to acid rain

    Science.gov (United States)

    Tsurumi, Takaaki; Takezawa, Shuhei; Hoshina, Takuya; Takeda, Hiroaki

    2017-10-01

    The amount of lead that eluted from lead zirconate titanate (PZT) ceramics to artificial acid rain was evaluated. Four kinds of PZT ceramics, namely, pure PZT at MPB composition, CuO-added PZT, PZT with 10 mol % substitution of Ba for Pb, and CuO-added PZT with 10 mol % substitution of Ba for Pb, were used as samples of the elution test. These PZT ceramics of 8 mm2 and 1.1-1.2 mm thickness were suspended in 300 ml of H2SO4 solution of pH 4.0. The concentration of lead eluted from PZT was in the range from 0.2 to 0.8 ppm. It was found that both liquid phase formation by the addition of CuO and the substitution of Ba for Pb were effective to reduce the amount of lead that eluted. By fitting the leaching out curve with a classical equation, a master curve assuming no sampling effect was obtained. The lead concentration evaluated from the amount of lead that eluted from a commercial PZT plate to H2SO4 solution of pH 5.3 was almost the same as the limit in city water. It is concluded that PZT is not harmful to health and the environment and the amount of lead that eluted from PZT can be controlled by modifying PZT composition.

  20. Radioactive cesium elution speed in dried wild Mushrooms collected in 2015

    International Nuclear Information System (INIS)

    Yamaguchi, Toshiro; Arai, Hirotsugu; Ohnuma, Tohru; Arai, Hiromu; Takyu, Sodai; Matsuyama, Tetsuo; Ishii, Keizo

    2016-01-01

    Dried wild mushrooms (12 species, 13 samples) collected in Nagano, Fukushima, and Miyagi Prefectures, Japan, in 2015 were immersed in water for 1,440 min. The elution rate of radioactive cesium (Cs) was calculated based on its radioactivity, which was measured with a high-purity germanium semiconductor detector (GX2018; CANBERRA Industries, Meriden, CT, USA) before and after immersion for each mushroom. Immersion fluid was sampled after 10, 30, 60, 180, 360, and 1,440 min of immersion and dried on aluminum foil. Then, imaging plates (BAS-III, Fujifilm, Tokyo, Japan) exposed to the dried immersion fluid were measured with a Bio-imaging Analyzer System-1800 II (Fujifilm). The 50% elution time of each wild mushroom was calculated based on the photo stimulated luminescence density of the autoradiographs. The radioactive Cs elution rate was > 80% for 11 samples (84% of total) comprising 11 mushroom species. Moreover, the 50% elution time was < 30 min for 9 samples (69% of total) comprising 9 species. This shows that the radioactive Cs elution rate and elution speed were not constant among mushroom species. Based on these results, immersing the mushrooms, which were dried, in water for at least 120 min is an effective method for removing radioactive Cs from wild mushrooms. (author)

  1. Transport due to ion temperature gradient mode vortex turbulence

    International Nuclear Information System (INIS)

    Pavlenko, V.P.; Weiland, J.

    1991-01-01

    The ion energy transport due to an ensemble of nonlinear vortices is calculated in the test particle approximation for a strongly turbulent plasma. A diffusion coefficient proportional to the root of the stationary turbulence level is obtained. (au)

  2. Endeavour zotarolimus-eluting stent reduces stent thrombosis and improves clinical outcomes compared with cypher sirolimus-eluting stent : 4-year results of the PROTECT randomized trial

    NARCIS (Netherlands)

    Wijns, William; Steg, Ph. Gabriel; Mauri, Laura; Kurowski, Volkhard; Parikh, Keyur; Gao, Runlin; Bode, Christoph; Greenwood, John P.; Lipsic, Erik; Alamgir, Farqad; Rademaker-Havinga, Tessa; Boersma, Eric; Radke, Peter; van Leeuwen, Frank; Camenzind, Edoardo

    2014-01-01

    Aims To compare the long-term clinical safety between two drug-eluting stents with different healing characteristics in the Patient Related Outcomes with Endeavour (E-ZES) vs. Cypher (C-SES) Stenting Trial (PROTECT). At 3 years, there was no difference in the primary outcome of definite or probable

  3. A randomised comparison of an everolimus-eluting coronary stent with a paclitaxel-eluting coronary stent:the SPIRIT II trial

    NARCIS (Netherlands)

    Serruys, Patrick W.; Ruygrok, Peter; Neuzner, Jörg; Piek, Jan J.; Seth, Ashok; Schofer, Joachim J.; Richardt, Gert; Wiemer, Marcus; Carrié, Didier; Thuesen, Leif; Boone, Els; Miquel-Herbert, Karine; Daemen, Joost

    2006-01-01

    Background: Everolimus has been successfully tested in humans using both an erodable and a durable polymer in small previous studies.Methods: This single blind multi-centre non-inferiority randomised (3:1) controlled trial evaluated the safety and performance of the XIENCE V Everolimus Eluting

  4. New Edge Coherent Mode Providing Continuous Transport in Long Pulse H-mode Plasmas

    DEFF Research Database (Denmark)

    Wang, H.Q.; Xu, G.S.; Wan, B.N.

    2014-01-01

    An electrostatic coherent mode near the electron diamagnetic frequency (20–90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Super-conducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciproc...

  5. Enhanced Photovoltaic Properties of Gradient Doping Solar Cells

    International Nuclear Information System (INIS)

    Zhang Chun-Lei; Du Hui-Jing; Zhu Jian-Zhuo; Xu Tian-Fu; Fang Xiao-Yong

    2012-01-01

    An optimum design of a-Si:H(n)/a-Si:H(i)/c-Si(p) heterojunction solar cell is realized with 24.27% conversion efficiency by gradient doping of the a-Si:H(n) layer. The photovoltaic properties are simulated by the AFORSHET software. Besides the additional electric field caused by the gradient doping, the enhanced and widen spectral response also improves the solar cell performance compared with the uniform-doping mode. The simulation shows that the gradient doping is efficient to improve the photovoltaic performance of the solar cells. The study is valuable for the solar cell design with excellent performances

  6. Separation of cannabinoids on three different mixed-mode columns containing carbon/nanodiamond/amine-polymer superficially porous particles.

    Science.gov (United States)

    Hung, Chuan-Hsi; Zukowski, Janusz; Jensen, David S; Miles, Andrew J; Sulak, Clayton; Dadson, Andrew E; Linford, Matthew R

    2015-09-01

    Three mixed-mode high-performance liquid chromatography columns packed with superficially porous carbon/nanodiamond/amine-polymer particles were used to separate mixtures of cannabinoids. Columns evaluated included: (i) reversed phase (C18 ), weak anion exchange, 4.6 × 33 mm, 3.6 μm, and 4.6 × 100 mm, 3.6 μm, (ii) reversed phase, strong anion exchange (quaternary amine), 4.6×33 mm, 3.6 μm, and (iii) hydrophilic interaction liquid chromatography, 4.6 × 150 mm, 3.6 μm. Different selectivities were achieved under various mobile phase and stationary phase conditions. Efficiencies and peak capacities were as high as 54 000 N/m and 56, respectively. The reversed phase mixed-mode column (C18 ) retained tetrahydrocannabinolic acid strongly under acidic conditions and weakly under basic conditions. Tetrahydrocannabinolic acid was retained strongly on the reversed phase, strong anion exchange mixed-mode column under basic polar organic mobile phase conditions. The hydrophilic interaction liquid chromatography column retained polar cannabinoids better than the (more) neutral ones under basic conditions. A longer reversed phase (C18 ) mixed-mode column (4.6 × 100 mm) showed better resolution for analytes (and a contaminant) than a shorter column. Fast separations were achieved in less than 5 min and sometimes 2 min. A real world sample (bubble hash extract) was also analyzed by gradient elution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The prognostic utility of the SYNTAX score on 1-year outcomes after revascularization with zotarolimus- and everolimus-eluting stents: a substudy of the RESOLUTE All Comers Trial

    DEFF Research Database (Denmark)

    Garg, Scot; Serruys, Patrick W; Silber, Sigmund

    2011-01-01

    This study assessed the ability of the SYNTAX score (SXscore) to stratify risk in patients treated with percutaneous coronary intervention (PCI) using zotarolimus-eluting or everolimus-eluting stents.......This study assessed the ability of the SYNTAX score (SXscore) to stratify risk in patients treated with percutaneous coronary intervention (PCI) using zotarolimus-eluting or everolimus-eluting stents....

  8. Tacoma mode

    International Nuclear Information System (INIS)

    Courant, E.D.; Ruth, R.D.; Wang, J.M.

    1979-01-01

    The name Tacoma refers to the Tacoma Narrows Bridge which collapsed on November 8, 1940 due to massive oscillations caused by high winds. One of the destructive modes was a torsion mode which was excited by transverse wind, a dipole force, and continued until the bridge collapsed. The name is used to refer to a coherent mode of oscillation of a spectrum of oscillators in which the amplitude vs frequency graph contains one node, where the node occurs near the driving frequency and a ω is not symmetric about zero. When this result is applied to vertical instabilities in coasting beams, it implies the existence of a coherent skew quadrupole moment, Q/sub xy/, whenever a coherent dipole oscillation exists

  9. Tacoma mode

    International Nuclear Information System (INIS)

    Courant, E.D.; Ruth, R.D.; Wang, J.M.

    1979-01-01

    The name Tacoma refers to the Tacoma Narrows Bridge which collapsed on November 8, 1940 due to massive oscillations caused by high winds. One of the destructive modes was a torsion mode which was excited by transverse wind, a dipole force, and continued until the bridge collapsed. The name is used to refer to a coherent mode of oscillation of a spectrum of oscillators in which the amplitude vs frequency graph contains one node, where the node occurs near the driving frequency and a(ω) is not symmetric about zero. When this result is applied to vertical instabilities in coasting beams, it implies the existence of a coherent skew quadrupole moment, whenever a coherent dipole oscillation exists

  10. Bigravity from gradient expansion

    International Nuclear Information System (INIS)

    Yamashita, Yasuho; Tanaka, Takahiro

    2016-01-01

    We discuss how the ghost-free bigravity coupled with a single scalar field can be derived from a braneworld setup. We consider DGP two-brane model without radion stabilization. The bulk configuration is solved for given boundary metrics, and it is substituted back into the action to obtain the effective four-dimensional action. In order to obtain the ghost-free bigravity, we consider the gradient expansion in which the brane separation is supposed to be sufficiently small so that two boundary metrics are almost identical. The obtained effective theory is shown to be ghost free as expected, however, the interaction between two gravitons takes the Fierz-Pauli form at the leading order of the gradient expansion, even though we do not use the approximation of linear perturbation. We also find that the radion remains as a scalar field in the four-dimensional effective theory, but its coupling to the metrics is non-trivial.

  11. Gradient-Index Optics

    Science.gov (United States)

    2010-03-31

    nonimaging design capabilities to incorporate 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 12-04-2011 13. SUPPLEMENTARY NOTES The views, opinions...Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS Imaging Optics, Nonimaging Optics, Gradient Index Optics, Camera, Concentrator...imaging and nonimaging design capabilities to incorporate manufacturable GRIN lenses can provide imaging lens systems that are compact and

  12. Failure Modes

    DEFF Research Database (Denmark)

    Jakobsen, K. P.; Burcharth, H. F.; Ibsen, Lars Bo

    1999-01-01

    The present appendix contains the derivation of ten different limit state equations divided on three different failure modes. Five of the limit state equations can be used independently of the characteristics of the subsoil, whereas the remaining five can be used for either drained or undrained s...

  13. Elution of Artificial Sputum from Swab by Rotating Magnetic Field-Induced Mechanical Impingement

    Directory of Open Access Journals (Sweden)

    Shubham Banik

    2017-12-01

    Full Text Available Cotton-tipped applicator swabs are used as a collection device for many biological samples and its complete elution is a desired step for clinical and forensic diagnostics. Swabs are used to collect infectious body fluids, where the concentration of pathogens can range from 1 × 104 CFU/mL (colony forming units/mL in respiratory-tract infections and 1 × 105 in urinary-tract infections, to up to 1 × 109 CFU/mL in salivary samples. These samples are then eluted and lysed, prior to DNA (De-oxy Ribonucleic Acid analysis. The recovery of micro-organisms from a matrix of swab fibres depends on the nature of the body fluid, the type of the swab fibres, and the process of elution. Various methods to elute samples from swab include chemical digestion of fibres (~20% recovery, centrifugation (~58% recovery, piezoelectric vibration, or pressurized fluid-flow (~60% recovery. This study reports a magnetically-actuated physical impingement method for elution and recovery of artificial sputum samples from cotton fibres. A device has been fabricated to induce a rotating magnetic field on smaller magnetic particles in a vial that strikes the swab within a confined gap. Elution from the swab in this device was characterized using 2% Methyl cellulose in deionised water, loaded with fluorescent-tagged polystyrene beads and E. coli at various concentrations. The recovery efficiency was found to increase with both rotational speed and elution time, but plateaus after 400 RPM (Revolutions per minute and 120 s, respectively. At a higher concentration of polystyrene beads (5 × 108 particles/mL, a maximum recovery of ~85% was achieved. With lower concentration, (1 × 105 particles/mL the maximum efficiency (~92.8% was found to be almost twice of passive elution (46.7%. In the case of E. coli, the corresponding recovery efficiency at 3.35 × 105 CFU/mL is 90.4% at 500 RPM and 120 s. This elution method is expected to have a wide applicability in clinical diagnostics.

  14. The integrated contaminant elution and tracer test toolkit, ICET3, for improved characterization of mass transfer, attenuation, and mass removal

    Science.gov (United States)

    Brusseau, Mark L.; Guo, Zhilin

    2018-01-01

    It is evident based on historical data that groundwater contaminant plumes persist at many sites, requiring costly long-term management. High-resolution site-characterization methods are needed to support accurate risk assessments and to select, design, and operate effective remediation operations. Most subsurface characterization methods are generally limited in their ability to provide unambiguous, real-time delineation of specific processes affecting mass-transfer, transformation, and mass removal, and accurate estimation of associated rates. An integrated contaminant elution and tracer test toolkit, comprising a set of local-scale groundwater extraction-and injection tests, was developed to ameliorate the primary limitations associated with standard characterization methods. The test employs extended groundwater extraction to stress the system and induce hydraulic and concentration gradients. Clean water can be injected, which removes the resident aqueous contaminant mass present in the higher-permeability zones and isolates the test zone from the surrounding plume. This ensures that the concentrations and fluxes measured within the isolated area are directly and predominantly influenced by the local mass-transfer and transformation processes controlling mass removal. A suite of standard and novel tracers can be used to delineate specific mass-transfer and attenuation processes that are active at a given site, and to quantify the associated mass-transfer and transformation rates. The conceptual basis for the test is first presented, followed by an illustrative application based on simulations produced with a 3-D mathematical model and a brief case study application.

  15. Establishing conditions for the storage and elution of rabies virus RNA using FTA® cards

    Science.gov (United States)

    SAKAI, Takeo; ISHII, Ayako; SEGAWA, Takao; TAKAGI, Yukihiko; KOBAYASHI, Yuki; ITOU, Takuya

    2014-01-01

    The Flinders Technology Associates filter paper cards (FTA® cards) can be used to store nucleic acid from various samples and are easily portable. However, RNA is physicochemically unstable compared with DNA, and appropriate methods have not been established for storage and extraction of RNA from FTA® cards. The present study investigated the optimum conditions for storage and elution of viral RNA (vRNA) using rabies virus (RABV) applied to FTA® cards. When TE buffer was used, the elution rates of vRNA increased with the length of the elution time. When the cards were stored at −80°C or −20°C, vRNA was stable over 3 months. Degradation of vRNAs occurred following storage at 4°C and room temperature, suggesting that RNA should be extracted from cards as soon as possible if no freezer is available. When we tried to amplify vRNA from RABV-infected animal brains applied to FTA® cards and stored at −80°C for 6 months, we did not detect any amplified products with the primer set for 964 bp of RABV N gene. However, we were able to detect amplified products by increasing the elution time of vRNA from FTA® cards from 30 min to 24 hr or by changing the primer sets to amplify 290 bp of N gene. Thus, we recommend extending the elution time for damaged or low concentration samples in FTA® cards. PMID:25648208

  16. Aluminum elution and precipitation in glass vials: effect of pH and buffer species.

    Science.gov (United States)

    Ogawa, Toru; Miyajima, Makoto; Wakiyama, Naoki; Terada, Katsuhide

    2015-02-01

    Inorganic extractables from glass vials may cause particle formation in the drug solution. In this study, the ability of eluting Al ion from borosilicate glass vials, and tendencies of precipitation containing Al were investigated using various pHs of phosphate, citrate, acetate and histidine buffer. Through heating, all of the buffers showed that Si and Al were eluted from glass vials in ratios almost the same as the composition of borosilicate glass, and the amounts of Al and Si from various buffer solutions at pH 7 were in the following order: citrate > phosphate > acetate > histidine. In addition, during storage after heating, the Al concentration at certain pHs of phosphate and acetate buffer solution decreased, suggesting the formation of particles containing Al. In citrate buffer, Al did not decrease in spite of the high elution amount. Considering that the solubility profile of aluminum oxide and the Al eluting profile of borosilicate glass were different, it is speculated that Al ion may be forced to leach into the buffer solution according to Si elution on the surface of glass vials. When Al ions were added to the buffer solutions, phosphate, acetate and histidine buffer showed a decrease of Al concentration during storage at a neutral range of pHs, indicating the formation of particles containing Al. In conclusion, it is suggested that phosphate buffer solution has higher possibility of forming particles containing Al than other buffer solutions.

  17. Innovative Elution Processes for Recovering Uranium and Transition Metals from Amidoxime-based Adsorbents

    Energy Technology Data Exchange (ETDEWEB)

    Wai, Chien M. [Univ. of Idaho, Moscow, ID (United States). Dept. of Chemistry

    2017-04-18

    Amidoxime-based polymer fibers are considered one of the most promising materials for sequestering uranium from seawater. The high-surface-area polymer fibers containing amidoxime and carboxylate groups synthesized by Oak Ridge National Lab (ORNL-AF1) show very high uranium adsorption capacities known in the literature. Effective elution of uranium and repeated use of the adsorbent are important factors affecting the cost of producing uranium from seawater using this material. Traditional acid leaching of uranium followed by KOH conditioning of the fiber causes chemical changes and physical damage to the ORNL-AF1 adsorbent. Two alkaline solution leaching methods were developed by this project, one uses a highly concentrated (3 M) potassium bicarbonate solution at pH 8.3 and 40 °C; the other uses a mixture of sodium carbonate and hydrogen peroxide at pH 10.4. Both elution methods do not require KOH conditioning prior to reusing the fiber adsorbent. The conditions of eluting uranium from the amidoxime-based adsorbent using these alkaline solutions are confirmed by thermodynamic calculations. The bicarbonate elution method is selective for uranium recovery compared to other elution methods and causes no chemical change to the fiber material based on FTIR spectroscopy

  18. Randomized comparison of a sirolimus-eluting Orsiro stent with a biolimus-eluting Nobori stent in patients treated with percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Thayssen, Per; Maeng, Michael

    2015-01-01

    BACKGROUND: Third-generation coronary drug-eluting stents (DES) with biodegradable polymers have been designed to improve safety and efficacy. We designed a large scale registry-based randomized clinical trial to compare 2 third-generation DES: a thin strut, cobalt-chromium DES with silicon carbide......-coating releasing sirolimus from a biodegradable polymer (O-SES, Orsiro; Biotronik, Bülach, Switzerland) with the stainless steel biodegradable polymer biolimus-eluting Nobori stents (N-BES, Nobori; Terumo, Tokyo, Japan) in an all-comer patient population. DESIGN: The multicenter SORT OUT VII trial (NCT01879358...... will be used. An event rate of 6.5% is assumed in each stent group. With a sample size of 1,157 patients in each treatment arm, a 2-group large-sample normal approximation test of proportions with a 1-sided 5% significance level will have 90% power to detect noninferiority of the O-SES compared with the N...

  19. Analysis of the role of elution buffers on the separation capabilities of dielectrophoretic devices

    Directory of Open Access Journals (Sweden)

    Rossana Di Martino

    2016-03-01

    Full Text Available Field flow fractionation dielectrophoretic (FFF-DEP devices are currently used, among the others, for the separation of tumor cells from healthy blood cells. To this end specific suspension/elution buffers (EBs, with reduced conductivity (with respect to that of the cell cytoplasm are generally used. In this paper we investigate the long-term alterations of the cells and elution buffers. We find that the EB conductivity is critically modified within few minutes after cells suspension. In turn, this modification results in a change the ideal separation frequency of the FFF-DEP device. On the other hand we prove that DEP manipulation is preserved for more than three hours for cells suspended in the considered EBs. Keywords: Dielectrophoresis, Elution buffer, Circulating tumor cells, Cell motility

  20. Wetting of flat gradient surfaces.

    Science.gov (United States)

    Bormashenko, Edward

    2018-04-01

    Gradient, chemically modified, flat surfaces enable directed transport of droplets. Calculation of apparent contact angles inherent for gradient surfaces is challenging even for atomically flat ones. Wetting of gradient, flat solid surfaces is treated within the variational approach, under which the contact line is free to move along the substrate. Transversality conditions of the variational problem give rise to the generalized Young equation valid for gradient solid surfaces. The apparent (equilibrium) contact angle of a droplet, placed on a gradient surface depends on the radius of the contact line and the values of derivatives of interfacial tensions. The linear approximation of the problem is considered. It is demonstrated that the contact angle hysteresis is inevitable on gradient surfaces. Electrowetting of gradient surfaces is discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. An everolimus-eluting stent versus a paclitaxel-eluting stent in small vessel coronary artery disease: a pooled analysis from the SPIRIT II and SPIRIT III trials.

    Science.gov (United States)

    Bartorelli, Antonio L; Serruys, Patrick W; Miquel-Hébert, Karine; Yu, Shui; Pierson, Wes; Stone, Gregg W

    2010-07-01

    To evaluate the safety and efficacy of the XIENCE V everolimus-eluting stent compared to the TAXUS paclitaxel-eluting stent in small vessels. The XIENCE V everolimus-eluting stent (EES) has been shown to improve angiographic and clinical outcomes after percutaneous myocardial revascularization, but its performance in small coronary arteries has not been investigated. In this pooled analysis, we studied a cohort of 541 patients with small coronary vessels (reference diameter SPIRIT II and SPIRIT III studies. TAXUS Express (73% of lesions) and TAXUS Liberté (27% of lesions) paclitaxel-eluting stents (PES) were used as controls in SPIRIT II. In SPIRIT III, Taxus Express(2) PES was the control. Mean angiographic in-stent and in-segment late loss was significantly less in the EES group compared with the PES group, (0.15 +/- 0.37 mm vs. 0.30 +/- 0.44 mm; P = 0.011 for in-stent; 0.10 +/- 0.38 mm vs. 0.21 +/- 0.34 mm; P = 0.034 for in-segment). EES also resulted in a significant reduction in composite major adverse cardiac events at 1 year (19/366 [5.2%] vs. 17/159 [10.7%]; P = 0.037), due to fewer non-Q-wave myocardial infarctions and target lesion revascularizations. At 1 year, the rate of non-Q-wave myocardial infarction was significantly lower in the EES group compared with that of the PES group (6/366 [1.6%] vs. 8/159 [5.0%]; P = 0.037). In patients with small vessel coronary arteries, the XIENCE V EES was superior to the TAXUS PES. (c) 2010 Wiley-Liss, Inc.

  2. Paclitaxel-eluting versus sirolimus-eluting stents in diabetes mellitus: a report from the National Heart, Lung, and Blood Institute Dynamic Registry.

    Science.gov (United States)

    Wolf, William M; Vlachos, Helen A; Marroquin, Oscar C; Lee, Joon S; Smith, Conrad; Anderson, William D; Schindler, John T; Holper, Elizabeth M; Abbott, J Dawn; Williams, David O; Laskey, Warren K; Kip, Kevin E; Kelsey, Sheryl F; Mulukutla, Suresh R

    2010-02-01

    Diabetes is a powerful predictor of adverse events in patients undergoing percutaneous coronary intervention. Drug-eluting stents reduce restenosis rates compared with bare metal stents; however, controversy remains regarding which drug-eluting stents provides greater benefit in patients with diabetes. Accordingly, we compared the safety and efficacy of sirolimus-eluting stents (SES) with paclitaxel-eluting stents (PES) among diabetic patients in a contemporary registry. Using the National Heart, Lung, and Blood Institute Dynamic Registry, we evaluated 2-year outcomes of diabetic patients undergoing percutaneous coronary interventions with SES (n=677) and PES (n=328). Clinical and demographic characteristics, including age, body mass index, insulin use, left ventricular function, and aspirin/clopidogrel use postprocedure, did not differ significantly between the groups except that PES-treated patients had a greater frequency of hypertension and hyperlipidemia. At the 2-year follow-up, no significant differences were observed between PES and SES with regard to safety or efficacy end points. PES- and SES-treated patients had similar rates of death (10.7% versus 8.2%, P=0.20), death and myocardial infarction (14.9% versus 13.6%, P=0.55), repeat revascularization (14.8% versus 17.8%, P=0.36), and stent thrombosis (1.3% versus 1.3%, P=0.95). After adjustment, no significant differences between the 2 stent types in any outcome were observed. PES and SES are equally efficacious and have similar safety profiles in diabetic patients undergoing percutaneous coronary interventions in clinical practice.

  3. Safety and efficacy of everolimus-eluting stents compared with first-generation drug-eluting stents in patients undergoing primary percutaneous coronary intervention

    Energy Technology Data Exchange (ETDEWEB)

    Escárcega, Ricardo O.; Baker, Nevin C.; Magalhaes, Marco A.; Lipinski, Michael J.; Minha, Sa’ar; Torguson, Rebecca; Satler, Lowell F.; Pichard, Augusto D.; Suddath, William O.; Waksman, Ron, E-mail: ron.waksman@medstar.net

    2014-09-15

    Objective: To assess the safety and efficacy everolimus-eluting stents (EES) compared with first-generation drug-eluting stents (DES) in patients with acute myocardial infarction (MI) undergoing primary percutaneous coronary intervention (PCI). Background: EES have been associated with improved clinical outcomes compared to paclitaxel-eluting stents (PES) and with similar outcomes compared to sirolimus-eluting stents (SES). Methods: A total of 520 patients who presented with ST-elevation myocardial infarction (STEMI) from 2003 to 2013, who underwent primary PCI with DES, were retrospectively analyzed. Of these, 247 received SES, 136 PES, and 137 EES. Patients were followed up to 2 years for major adverse cardiac events (MACE). Univariate and multivariate models detected correlates to outcome. Results: EES implantation, compared with PES and SES, resulted in comparable rates of MACE (8.8% vs. 16.2%, p = 0.06 and 8.8% vs. 12.6%, respectively, p = 0.26), stent thrombosis, MI, and target lesion revascularization. Patients who received EES had lower rates of all-cause mortality (3.7% vs. 12.6% vs. 9.4%, p = 0.03) at 1-year follow up. However, in the univariate and multivariate analyses, stent type was not independently associated with the primary outcome or with all-cause mortality. Diabetes mellitus and number of stents implanted were independently associated with the primary outcome. Conclusion: While EES seem to be associated with better outcome when compared to PES, the main correlates of STEMI patients are the presence of diabetes and number of stents implanted, and not the type of stent used for intervention.

  4. Analysis of current diffusive ballooning mode

    International Nuclear Information System (INIS)

    Yagi, M.; Azumi, M.; Itoh, K.; Itoh, S.; Fukuyama, A.

    1993-04-01

    The current diffusive ballooning mode is analysed in the tokamak plasma. This mode is destabilized by the current diffusivity (i.e., the electron viscosity) and stabilized by the thermal conductivity and ion viscosity. By use of the ballooning transformation, the eigenmode equation is solved. Analytic solution is obtained by the strong ballooning limit. Numerical calculation is also performed to confirm the analytic theory. The growth rate of the mode and the mode structure are analysed. The stability boundary is derived in terms of the current diffusivity, thermal conductivity, ion viscosity and the pressure gradient for the given shear parameter. This result is applied to express the thermal conductivity in terms of the pressure gradient, magnetic configurational parameters (such as the safety factor, shear and aspect ratio) and the Prandtl numbers. (author)

  5. Drug elution from high-dose antibiotic-loaded acrylic cement: a comparative, in vitro study.

    Science.gov (United States)

    Gasparini, Giorgio; De Gori, Marco; Calonego, Giovanni; Della Bora, Tommaso; Caroleo, Benedetto; Galasso, Olimpio

    2014-11-01

    High-dose antibiotic-loaded acrylic cement (ALAC) is used for managing peri-prosthetic joint infections (PJIs). The marked increase in resistant high-virulence bacteria is drawing the attention of physicians toward alternative antimicrobial formulations loaded into acrylic bone cement. The aim of this in vitro study was to determine the elution kinetics of 14 different high-dose ALACs. All ALAC samples showed a burst release of antibiotics in the first hour, progressively decreasing over time, and elution curves strictly adhered to a nonlinear regression analysis formula. Among aminoglycosides, commonly seen as the most appropriate antibiotics to be loaded into the bone cement, the highest elution rate was that of tobramycin. Among the glycopeptides, a class of antibiotics that should be considered to treat PJIs because of the prevalence of aminoglycoside resistance, vancomycin showed better elution than teicoplanin. Clindamycin, which can be associated with aminoglycosides to prepare ALACs and represents a useful option against the most common pathogens responsible for PJIs, showed the highest absolute and relative elutions among all the tested formulations. A noticeable elution was also detected for colistin, an antibiotic of last resort for treating multidrug-resistant bacteria. The current study demonstrates theoretical advantages in the preparation of ALAC for some antibiotics not routinely used in the clinical setting for PJIs. The use of these antibiotics based on the infecting bacteria sensitivity may represent a useful option for physicians to eradicate PJIs. In vivo testing should be considered in the future to confirm the results of this study. Copyright 2014, SLACK Incorporated.

  6. Stent Coating Integrity of Durable and Biodegradable Coated Drug Eluting Stents.

    Science.gov (United States)

    Yazdani, Saami K; Sheehy, Alexander; Pacetti, Stephen; Rittlemeyer, Brandon; Kolodgie, Frank D; Virmani, Renu

    2016-10-01

    Coatings consisting of a polymer and drug are widely used in drug-eluting stents (DES) and are essential in providing programmable drug release kinetics. Among other factors, stent coating technologies can influence blood compatibility, affect acute and sub-acute healing, and potentially trigger a chronic inflammatory response. The aim of this study was to investigate the short-term (7 and 28 days) and long-term (90 and 180 days) coating integrity of the Xience Prime Everolimus-Eluting Stent (EES), Resolute Zotarolimus-Eluting Stent (ZES), Taxus Paclitaxel-Eluting Stent (PES), and Nobori Biolimus A9-Eluting Stent (BES) in a rabbit ilio-femoral stent model. Stented arteries (n = 48) were harvested and the tissue surrounding the implanted stents digested away with an enzymatic solution. Results demonstrated that the majority of struts of EES were without any coating defects with a few struts showing minor defects. Similarly, for the ZES, most of the struts were without coating defects at all time points except at 180 days. The majority of PES demonstrated mostly webbing and uneven coating. In the BES group, the majority of strut coating showed polymer cracking. Overall, the EES and ZES had fewer coating defects than the PES and BES. Coating defects, however increase over time for the ZES, whereas the percent of coating irregularities remained constant for the EES. These results provide, for the first time, a comparison of the long-term durability of these drug-eluting stent coatings in vivo. © 2016, Wiley Periodicals, Inc.

  7. Study to modify the elution system in a sup(99m)Tc generator

    International Nuclear Information System (INIS)

    Delgado S, Baldomero.

    1979-01-01

    The sup(99m)Tc generator is a system that allows us to obtain sup(99m)Tc through the radioactive desintegration of 99 Mo, a radionuclide absorbed in an alumine chromatographic column, the sup(99m)Tc extraction is accomplished by elution and the 99 Mo remains at the column. In this work we try to modify the elution procedure of the generator. At present after eluating the generator, it must be dried with air, in order to support the column in an oxidant atmosphere to avoid the reduction of the technetiate. This reduction causes a low yield of elution, since the reduced species of the technetium can not be eluated. The drying of the column with air complicates a little the elution procedure, and we look to simplify it, the employed methods to resolve the problem were: a) adding an oxidant agent to the elution saline solution, b) adsorbing an oxidant in the alumina chromatographic column, after that the 99 Mo was settled. In the case a) the used oxidant agents were KMnO 4 , K 2 Cr 2 O 7 , NaNo 2 , etc. At concentration rates of 10 -7 M the obtained yields in high activity generators were of the 25-30%. In the case b) variable amounts of a disolution of 2.5 mg/ml of K 2 CrO 4 were adsorbed, the obtained yields in high activity generators were about 85-90%, this second procedure was better, it lets us keep the column wet and it is not necessary to dry it with air, and in this way it can be carried out more easily and efficiently the elution procedure. (author)

  8. Drug-eluting stents and bare metal stents in patients with NSTE-ACS

    DEFF Research Database (Denmark)

    Pedersen, Sune Haahr; Pfisterer, Matthias; Kaiser, Christoph

    2014-01-01

    the randomised BASKET-PROVE trial (sirolimus-eluting stent vs. everolimus-eluting stent vs. bare metal stent in large-vessel stenting). The primary endpoint was the combined two-year rate of cardiovascular death or non-fatal myocardial infarction (MI). Secondary endpoints were each component of the primary...... implantation in large vessels was associated with a reduction in both TVR and the combined endpoint consisting of cardiovascular death/MI. Thus, DES use improves both efficacy and safety. These findings support the use of DES in NSTE-ACS patients....

  9. Involvement of COX-2 in nickel elution from a wire implanted subcutaneously in mice.

    Science.gov (United States)

    Sato, Taiki; Kishimoto, Yu; Asakawa, Sanki; Mizuno, Natsumi; Hiratsuka, Masahiro; Hirasawa, Noriyasu

    2016-07-01

    Many types of medical alloys include nickel (Ni), and the elution of Ni ions from these materials causes toxicities and inflammation. We have previously reported that inflammation enhances Ni elution, although the molecular mechanisms underlying this effect remain unclear. In this study, we investigated how inflammatory responses enhanced Ni elution in a wire-implantation mouse model. Subcutaneous implantation of Ni wire induced the expression of cyclooxygenase-2 (COX-2) and microsomal prostaglandin E synthase-1 (mPGES-1) mRNA in the surrounding tissues. Immunostaining analysis showed that cells expressing COX-2 were mainly fibroblast-like cells 8h after implantation of a Ni wire, but were mainly infiltrated leukocytes at 24h. NiCl2 induced the expression of COX-2 mRNA in primary fibroblasts, neutrophils, RAW 264 cells, and THP-1 cells, indicating that Ni ions can induce COX-2 expression in various types of cells. The elution of Ni ions from the implanted Ni wire at 8h was reduced by dexamethasone (Dex), indomethacin (Ind), or celecoxib (Cel) treatment. Ni wire implantation induced an increase in mRNA levels for anaerobic glycolytic pathway components glucose transporter 1 (GLUT1), hexokinase 2 (HK2), lactate dehydrogenase A (LDHA), and monocarboxylate transporter 4 (MCT4); the expression of these genes was also inhibited by Dex, Ind, and Cel. In primary fibroblasts, the expression of these mRNAs and the production of lactate were induced by NiCl2 and further potentiated by PGE2. Furthermore, Ni wire-induced infiltration of inflammatory leukocytes was significantly reduced by Dex, Ind, or Cel. Depletion of neutrophils with a specific antibody caused reduction of both leukocyte infiltration and Ni elution. These results indicate that Ni ions eluted from wire induced COX-2 expression, which further promoted elution of Ni ions by increasing lactate production and leukocyte infiltration. Since COX inhibitors and Dex reduced the elution of Ni ions, these drugs may be

  10. Cation exchange assisted binding-elution strategy for enzymatic synthesis of human milk oligosaccharides (HMOs).

    Science.gov (United States)

    Zhu, Hailiang; Wu, Zhigang; Gadi, Madhusudhan Reddy; Wang, Shuaishuai; Guo, Yuxi; Edmunds, Garrett; Guan, Wanyi; Fang, Junqiang

    2017-09-15

    A cation exchange assisted binding-elution (BE) strategy for enzymatic synthesis of human milk oligosaccharides (HMOs) was developed. An amino linker was used to provide the cation ion under acidic condition which can be readily bound to cation exchange resin and then eluted off by saturated ammonium bicarbonate. Ammonium bicarbonate in the collections was easily removed by vacuum evaporation. This strategy circumvented the incompatible issue between glycosyltransferases and solid support or large polymers, and no purification was needed for intermediate products. With current approach, polyLacNAc backbones of HMOs and fucosylated HMOs were synthesized smoothly. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. H-mode and confinement studies in ASDEX Upgrade

    International Nuclear Information System (INIS)

    Suttrop, W.; Ryter, F.; Mertens, V.; Gruber, O.; Murmann, H.; Salzmann, H.; Schweinzer, J.

    2001-01-01

    H-mode operational boundaries and H-mode confinement are investigated on ASDEX Upgrade. The local edge parameter threshold for H-mode holds independent of divertor geometry and changes little with ion mass. The deviation of the H-mode power threshold at densities near the Greenwald limit can be understood as a consequence of a confinement deterioration, caused by 'stiff' temperature profiles and lack of core density gradients in gas puff fuelled discharges. Ion and electron temperature profiles can be described by a lower limit of gradient length L T =T/T'. (author)

  12. Spin modes

    International Nuclear Information System (INIS)

    Gaarde, C.

    1985-01-01

    An analysis of spectra of (p,n) reactions showed that they were very selective in exciting spin modes. Charge exchange reactions at intermediate energies give important new understanding of the M1-type of excitations and of the spin structure of continuum p spectra in general. In this paper, the author discusses three charge exchange reactions: (p,n); ( 3 H,t); and (d,2p) at several targets. Low-lying states and the Δ region are discussed separately. Finally, the charge exchange reaction with heavy ion beams is briefly discussed. (G.J.P./Auth.)

  13. Theory of ion-temperature-gradient-driven turbulence in tokamaks

    International Nuclear Information System (INIS)

    Lee, G.S.; Diamond, P.H.

    1986-01-01

    An analytic theory of ion-temperature-gradient-driven turbulence in tokamaks is presented. Energy-conserving, renormalized spectrum equations are derived and solved in order to obtain the spectra of stationary ion-temperature-gradient-driven turbulence. Corrections to mixing-length estimates are calculated explicitly. The resulting anomalous ion thermal diffusivity chi/sub i/ = 0.4[(π/2)ln(1 + eta/sub i/)] 2 [(1 + eta/sub i/)/tau] 2 rho/sub s/ 2 c/sub s//L/sub s/ is derived and is found to be consistent with experimentally-deduced thermal diffusivities. The associated electron thermal diffusivity and particle and heat-pinch velocities are also calculated. The effect of impurity gradients on saturated ion-temperature-gradient-driven turbulence is discussed and a related explanation of density profile steepening during Z-mode operation is proposed. 35 refs., 4 figs

  14. Rationale and Design of a Randomized Clinical Comparison of Everolimus-Eluting (Xience V/Promus) and Sirolimus-Eluting (Cypher Select+) Coronary Stents in Unselected Patients with Coronary Heart Disease

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Thayssen, Per; Tilsted, Hans Henrik

    2010-01-01

    with Clinical Outcome (SORT OUT) IV trial was designed as a prospective, multi-center, open-label, all-comer, two-arm, randomized, non-inferiority study comparing the everolimus-eluting stent with the sirolimus-eluting stent in the treatment of atherosclerotic coronary artery lesions. Based on a non...

  15. Comparison of an everolimus-eluting bioresorbable scaffold with an everolimus-eluting metallic stent for the treatment of coronary artery stenosis (ABSORB II): a 3 year, randomised, controlled, single-blind, multicentre clinical trial

    NARCIS (Netherlands)

    Serruys, Patrick W.; Chevalier, Bernard; Sotomi, Yohei; Cequier, Angel; Carrié, Didier; Piek, Jan J.; van Boven, Ad J.; Dominici, Marcello; Dudek, Dariusz; McClean, Dougal; Helqvist, Steffen; Haude, Michael; Reith, Sebastian; de Sousa Almeida, Manuel; Campo, Gianluca; Iñiguez, Andrés; Sabaté, Manel; Windecker, Stephan; Onuma, Yoshinobu

    2016-01-01

    No medium-term data are available on the random comparison between everolimus-eluting bioresorbable vascular scaffolds and everolimus-eluting metallic stents. The study aims to demonstrate two mechanistic properties of the bioresorbable scaffold: increase in luminal dimensions as a result of

  16. Tissue coverage of a hydrophilic polymer-coated zotarolimus-eluting stent vs. a fluoropolymer-coated everolimus-eluting stent at 13-month follow-up: an optical coherence tomography substudy from the RESOLUTE All Comers trial

    DEFF Research Database (Denmark)

    Gutiérrez-Chico, Juan Luis; van Geuns, Robert Jan; Regar, Evelyn

    2011-01-01

    To compare the tissue coverage of a hydrophilic polymer-coated zotarolimus-eluting stent (ZES) vs. a fluoropolymer-coated everolimus-eluting stent (EES) at 13 months, using optical coherence tomography (OCT) in an 'all-comers' population of patients, in order to clarify the mechanism of eventual...

  17. Microtearing modes

    International Nuclear Information System (INIS)

    Garbet, X.; Mourgues, F.; Samain, A.; Zou, X.

    1990-01-01

    A serious degradation of confinement with additional heating is commonly observed on most tokamaks. The microtearing modes could provide an explanation for this experimental fact. They are driven linearly unstable by diamagnetism in collisional regimes, but it may be shown that the collisions in non linear regimes provide a small diffusion coefficient which can be only significant at the plasme edge. In the bulk of the plasma, the microtearing turbulence could play a basic role if it is unstable in the collisionless regime. While it is linearly stable without collisions, it could be driven unstable in realistic regimes by the radial diffusion it induces. To study this effect, we have used a model where the non linear action of the modes on a given helicity component is represented by a diffusion operator. They are found unstable for reasonable β p =2μ o nT/B 2 p , with a special radial profile of the potential vector A. The problem arises the validity of this model where non linearities in the trajectories behaviour are replaced by the diffusion which broadens resonances. To test this procedure, we calculate the actual electron distribution function when it is determined by the ergodicity of the field lines. We compute the correlations of the distribution function with the magnetic perturbation and compare them with the analytical expressions derived from the resonance broadening model. (author) 3 refs., 2 figs

  18. Tripolar vortex formation in dense quantum plasma with ion-temperature-gradients

    Science.gov (United States)

    Qamar, Anisa; Ata-ur-Rahman, Mirza, Arshad M.

    2012-05-01

    We have derived system of nonlinear equations governing the dynamics of low-frequency electrostatic toroidal ion-temperature-gradient mode for dense quantum magnetoplasma. For some specific profiles of the equilibrium density, temperature, and ion velocity gradients, the nonlinear equations admit a stationary solution in the form of a tripolar vortex. These results are relevant to understand nonlinear structure formation in dense quantum plasmas in the presence of equilibrium ion-temperature and density gradients.

  19. Tripolar vortex formation in dense quantum plasma with ion-temperature-gradients

    Energy Technology Data Exchange (ETDEWEB)

    Qamar, Anisa; Ata-ur-Rahman [Institute of Physics and Electronics, University of Peshawar, Khyber Pakhtoon Khwa 25000 (Pakistan); National Center for Physics Shahdrah Valley Road, Islamabad 44000 (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Physics Department, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

    2012-05-15

    We have derived system of nonlinear equations governing the dynamics of low-frequency electrostatic toroidal ion-temperature-gradient mode for dense quantum magnetoplasma. For some specific profiles of the equilibrium density, temperature, and ion velocity gradients, the nonlinear equations admit a stationary solution in the form of a tripolar vortex. These results are relevant to understand nonlinear structure formation in dense quantum plasmas in the presence of equilibrium ion-temperature and density gradients.

  20. Tripolar vortex formation in dense quantum plasma with ion-temperature-gradients

    International Nuclear Information System (INIS)

    Qamar, Anisa; Ata-ur-Rahman; Mirza, Arshad M.

    2012-01-01

    We have derived system of nonlinear equations governing the dynamics of low-frequency electrostatic toroidal ion-temperature-gradient mode for dense quantum magnetoplasma. For some specific profiles of the equilibrium density, temperature, and ion velocity gradients, the nonlinear equations admit a stationary solution in the form of a tripolar vortex. These results are relevant to understand nonlinear structure formation in dense quantum plasmas in the presence of equilibrium ion-temperature and density gradients.

  1. Instability and transport driven by an electron temperature gradient close to critical

    International Nuclear Information System (INIS)

    Dong, J.Q.; Jian, G.D.; Wang, A.K.; Sanuki, H.; Itoh, K.

    2003-01-01

    Electron temperature gradient (ETG) driven instability in toroidal plasmas is studied with gyrokinetic theory. The full electron kinetics is considered. The upgraded numerical scheme for solving the integral eigenvalue equations allows the study of both growing and damping modes, and thus direct calculation of critical gradient. Algebraic formulas for the critical gradient with respect to ratio of electron temperature over ion temperature and to toroidicity are given. An estimation for turbulence induced transport is presented. (author)

  2. Studies of the trapped particle and ion temperature gradient instabilities in the Columbia Linear Machine

    International Nuclear Information System (INIS)

    Mathey, O.H.

    1989-01-01

    In the first part of the work, the effects of weak Coulomb and neutral collisions on the collisionless curvature driven trapped particle mode are studied in the Columbia Linear Machine (CLM) [Phys. Rev. Lett. 57, 1729, (1986)]. Low Coulomb collisionality yields a small stabilizing correction to the magnetohydrodynamic (MHD) collisionless mode, which scales as v, using the Krook model, and ν ec 1/2 using a Lorentz pitch angle operator. In higher collisionality regimes, both models tend to yield similar scalings. In view of relative high neutral collisionality in CLM, both types of collisionality are then combined, modeling neutral collisions with the conserving Krook and Coulomb collisions with a Lorentz model. The dispersion relation is then integrated over velocity space. This combination yields results in very good accord with the available experimental data. The Ion Temperature Gradient Instability is then investigated. It is shown that anisotropy in gradient has a substantial effect on the ion temperature gradient driven mode. A gradient in the parallel temperature is needed for an instability to occur, and a gradient in the perpendicular temperature gradient further enhances the instability indirectly as long as the frequency of the mode is near ion resonance. The physical reason for this important role difference is presented. The Columbia Linear Machine is being redesigned to produce and identify the ion temperature gradient driven η i mode. Using the expected parameters, the author has developed detailed predictions of the mode characteristics in the CLM. Strong multi mode instabilities are expected. As the ion parallel and perpendicular ion temperature gradients are expected to differ significantly, we differentiate between η i parallel and ν i perpendicular and explore the physical differences between them, which leads to a scheme for stabilization of the mode

  3. Design study on quasi-constant gradient accelerator structure

    International Nuclear Information System (INIS)

    Wang, J.W.; Littmann, B.W.

    1991-09-01

    In order to obtain high luminosity, the Next Linear Collider will operate in multibunch mode with ten or more bunches per bunch train. This leads to the need for detuning and/or damping of higher modes to control multibunch beam breakup. Continued studies of wake fields for a detuned structure with a Gaussian distribution of dipole modes showed encouraging results, and a detuned structure model has been tested experimentally. It is desirable to study the design method for this type of structure, which has a quasi-constant accelerating gradient. This note gives a brief summary of the design procedure. Also, the RF parameters of the structure are evaluated to compare with conventional constant gradient and constant impedance structures

  4. SOLID-PHASE EXTRACTION OF MORPHINE FROM WHOLE-BLOOD BY MEANS OF BOND ELUT CERTIFY COLUMNS

    NARCIS (Netherlands)

    CHEN, XH; HOMMERSON, ALC; ZWEIPFENNING, PGM; FRANKE, JP; HARMENBOVERHOF, CW; ENSING, K; DEZEEUW, RA

    The use of Bond Elut Certify columns for the isolation of morphine from whole blood was evaluated. In order to monitor possible losses and the elution profile of morphine, a small amount of the tritiated analogue was added to the samples. Four sample pretreatment methods, three protein precipitation

  5. Comparison of paclitaxel- and sirolimus-eluting stents in everyday clinical practice: the SORT OUT II randomized trial

    DEFF Research Database (Denmark)

    Galløe, Anders M; Thuesen, Leif; Kelbaek, Henning

    2008-01-01

    Approval of drug-eluting coronary stents was based on results of relatively small trials of selected patients; however, in routine practice, stents are used in a broader spectrum of patients.......Approval of drug-eluting coronary stents was based on results of relatively small trials of selected patients; however, in routine practice, stents are used in a broader spectrum of patients....

  6. Elution strategies for reversed-phase high-performance liquid chromatography analysis of sucrose alkanoate regioisomers with charged aerosol detection

    DEFF Research Database (Denmark)

    Lie, Aleksander; Pedersen, Lars Haastrup

    2013-01-01

    A broad range of elution strategies for RP-HPLC analysis of sucrose alkanoate regioisomers with CAD was systematically evaluated. The HPLC analyses were investigated using design-of-experiments methodology and analysed by analysis of variance (ANOVA) and regression modelling. Isocratic elutions, ...

  7. Gradient Boosting Machines, A Tutorial

    Directory of Open Access Journals (Sweden)

    Alexey eNatekin

    2013-12-01

    Full Text Available Gradient boosting machines are a family of powerful machine-learning techniques that have shown considerable success in a wide range of practical applications. They are highly customizable to the particular needs of the application, like being learned with respect to different loss functions. This article gives a tutorial introduction into the methodology of gradient boosting methods. A theoretical information is complemented with many descriptive examples and illustrations which cover all the stages of the gradient boosting model design. Considerations on handling the model complexity are discussed. A set of practical examples of gradient boosting applications are presented and comprehensively analyzed.

  8. Drug-eluting versus bare-metal stents in large coronary arteries

    DEFF Research Database (Denmark)

    Kaiser, Christoph; Galatius, Soeren; Erne, Paul

    2010-01-01

    Recent data have suggested that patients with coronary disease in large arteries are at increased risk for late cardiac events after percutaneous intervention with first-generation drug-eluting stents, as compared with bare-metal stents. We sought to confirm this observation and to assess whether...

  9. AN ALTERNATIVE ELUENT TO BEEF EXTRACT FOR ELUTING POLIOVIRUS FROM ELECTROPOSITIVE FILTERS

    Science.gov (United States)

    Traditional methods for enteric virus removal from waters involve filtering the water through a positively charged filter followed by elution with beef extract, second step concentration by flocculation, and assay in cell culture. Two of the problems associated with this method ...

  10. Drug-eluting stents: from bench-top to clinical research

    NARCIS (Netherlands)

    Basalus, Mounir Welson Zakhary

    2013-01-01

    The development of drug-eluting stents (DES) has improved the invasive treatment of obstructive coronary artery disease by reducing both, restenosis rate and need for reinterventions. This success resulted in a widespread utilization of DES in clinical practice and entailed many clinical research

  11. Drug-Eluting Balloons in the Treatment of Coronary De Novo Lesions

    DEFF Research Database (Denmark)

    Richelsen, Rasmus Kapalu Broge; Overvad, Thure Filskov; Jensen, Svend Eggert

    2016-01-01

    Drug-eluting balloons (DEBs) have emerged as a new application in percutaneous coronary intervention. DEBs have proven successful in the treatment of in-stent restenosis, but their role in de novo lesions is less clear. This paper provides a review of the current studies where DEBs have been used...

  12. Enhanced performance of magnesium alloy for drug-eluting vascular scaffold application

    Science.gov (United States)

    Dong, Hongzhou; Li, Daikun; Mao, Daoyong; Bai, Ningning; Chen, Yashi; Li, Qing

    2018-03-01

    Bio-absorbable magnesium alloys drug-eluting vascular scaffold was developed to resolve the defect of permanent metal and drug-eluting stents, most notably a chronic vessel wall inflammation and the risk of stent thrombosis. Nevertheless, violent chemical reaction and rapid degradation under physiological conditions limits their application. Furthermore, multifunctional drug-eluting stents which could reduce the formation of thrombus and repair the damaged vessels need more attention to fundamentally cure the coronary artery disease. Herein, a drug delivery system (Mg/MgO/PLA-FA) which can realize sustainable release of ferulaic acid was designed via anodic oxidation process and dip coating process. Electrochemical tests and immersion experiments showed that the superior anticorrosion behavior, it is due to the dense MgO-PLA composite layer. The released ferulaic acid can effectively decrease platelets adhesion and aggregation during the early stage of implantation. Besides, hemolysis tests showed that the composite coatings endowed the Mg alloy with a low hemolysis ratio. The Mg/MgO/PLA-FA composite materials may be appropriate for applications on biodegradable Mg alloys drug-eluting stents.

  13. Studies on the production of technetium-99m generators based on gel elution

    International Nuclear Information System (INIS)

    Castro, M.

    1993-12-01

    Technetium-99m generator based on Ti Mo elution has been carried out. The gel matrix was prepared by mixing non-irradiated molybdate with Titanium Chloride solution. Conditions of preparing and drying Ti Mo were evaluated as a function of elution yield. Thus, pH and water content were found highly critical for reproductiveness of the results. Non-elutable form of Tc-99m can be oxidized treating the target after irradiation with K 2 Cr 2 O 7 0.001M solution. During several experiments the columns were soaked with this oxidizing solution for one hour and afterwards the Ti Mo was washed with 150 ml physiological saline. Daily elutions were done with 10 ml of NaCl 0.9%. Cooling water reactor during irradiation quartz ampoules has been studied. To study this effect, one group of samples were irradiated in aluminium caps air-tight screw and another one was irradiated in drilled caps with six holes to permit water reactor recirculation around quartz ampoules. By combination K 2 Cr 2 O 7 target treatment and cooling Ti Mo during irradiation is possible to get yields of Tc-99m near to 76%. The radiochemical purity was > 99% and Al content < 10ppm , Cr < 0.05ppm , Mo <20ppm, Ti was no detected. Biological scans practiced in animals have been considered satisfactory. (author). 8 refs., 7 tabs., 3 figs

  14. Clopidogrel discontinuation within the first year after coronary drug-eluting stent implantation

    DEFF Research Database (Denmark)

    Thim, Troels; Johansen, Martin Berg; Chisholm, Gro Egholm

    2014-01-01

    BACKGROUND: The impact of adherence to the recommended duration of dual antiplatelet therapy after first generation drug-eluting stent implantation is difficult to assess in real-world settings and limited data are available. METHODS: We followed 4,154 patients treated with coronary drug-eluting ......BACKGROUND: The impact of adherence to the recommended duration of dual antiplatelet therapy after first generation drug-eluting stent implantation is difficult to assess in real-world settings and limited data are available. METHODS: We followed 4,154 patients treated with coronary drug......-eluting stents in Western Denmark for 1 year and obtained data on redeemed clopidogrel prescriptions and major adverse cardiovascular events (MACE, i.e., cardiac death, myocardial infarction, or stent thrombosis) from medical databases. RESULTS: Discontinuation of clopidogrel within the first 3 months after...... stent implantation was associated with a significantly increased rate of MACE at 1-year follow-up (hazard ratio (HR) 2.06; 95% confidence interval (CI): 1.08-3.93). Discontinuation 3-6 months (HR 1.29; 95% CI: 0.70-2.41) and 6-12 months (HR 1.29; 95% CI: 0.54-3.07) after stent implantation were...

  15. Optimized pH method for DNA elution from buccal cells collected in Whatman FTA cards.

    Science.gov (United States)

    Lema, Carolina; Kohl-White, Kendra; Lewis, Laurie R; Dao, Dat D

    2006-01-01

    DNA is the most accessible biologic material for obtaining information from the human genome because of its molecular stability and its presence in every nucleated cell. Currently, single nucleotide polymorphism genotyping and DNA methylation are the main DNA-based approaches to deriving genomic and epigenomic disease biomarkers. Upon the discontinuation of the Schleicher & Schuell IsoCode product (Dassel, Germany), which was a treated paper system to elute DNA from several biologic sources for polymerase chain reaction (PCR) analysis, a high-yielding DNA elution method was imperative. We describe here an improved procedure of the not fully validated Whatman pH-based elution protocol. Our DNA elution procedure from buccal cells collected in Whatman FTA cards (Whatman Inc., Florham Park, NJ) yielded approximately 4 microg of DNA from a 6-mm FTA card punch and was successfully applied for HLA-DQB1 genotyping. The genotypes showed complete concordance with data obtained from blood of the same subjects. The achieved high DNA yield from buccal cells suggests a potential cost-effective tool for genomic and epigenomic disease biomarkers development.

  16. Impaired health status in Type D patients following PCI in the drug-eluting stent era

    DEFF Research Database (Denmark)

    Pedersen, Susanne S.; Denollet, Johan; Ong, Andrew T L

    2007-01-01

    Drug-eluting stenting reduces restenosis post-percutaneous coronary intervention (PCI), but subgroups of patients may not benefit optimally from this procedure. We examined the impact of Type D personality on health status over time and the clinical relevance of Type D as a predictor of impaired...... health status at 12 months in unselected post-PCI patients....

  17. Investigations on the elution behaviour of TOPO complexes of uranium and thorium using supercritical fluid chromatography

    International Nuclear Information System (INIS)

    Kumar, R.; Sivaraman, N.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2004-01-01

    In summary uranium and thorium could be separated by supercritical fluid chromatography technique as their TOPO complexes. The elution profiles with pre-complexation of the metal nitrate indicate a better separation than the in-situ complexation. The technique can also be employed for the assay of uranium and thorium at low levels

  18. Offline coupling of low-pressure anion-exchange chromatography with MALDI-MS to determine the elution order of human milk oligosaccharides.

    Science.gov (United States)

    Finke, B; Mank, M; Daniel, H; Stahl, B

    2000-09-10

    Pooled human milk oligosaccharides were separated into neutral and several acidic oligosaccharide fractions by preparative anion-exchange chromatography (AEC) using AG 1-X2. The oligosaccharides were eluted stepwise using deionized water and three different concentrations of ammonium acetate buffer, pH 6.8. The elution order of the compounds was determined directly by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of the AEC effluent without any cleanup or concentration steps. Up to a concentration of 500 mM ammonium acetate, the masses of acidic oligosaccharides could be detected by screening the fractions in an automated mode. The combination of the improved chromatographic procedure, the applied MALDI matrices, and operating parameters is suitable for the detection of neutral oligosaccharides as well as acidic oligosaccharides. The method provides high sensitivity and mass accuracy, including for the high-molecular-weight monosialylated oligosaccharides up to 2751.5 Da. The applied ionic strength of the anion-exchange eluents enables a rapid and an unambiguous composition assignment by MALDI-MS for neutral, monosialylated, and disialylated oligosaccharides from human milk. The acidic fractions have to be desalted by electrodialysis and were finally analyzed by HPAEC-PAD to get a high-resolution "fingerprint" of structures present in each fraction. From these analyses, it can be concluded that the isomeric variety of monosialylated oligosaccharides occurring in human milk is higher than estimated before. Copyright 2000 Academic Press.

  19. Gradient waveform synthesis for magnetic propulsion using MRI gradient coils

    International Nuclear Information System (INIS)

    Han, B H; Lee, S Y; Park, S

    2008-01-01

    Navigating an untethered micro device in a living subject is of great interest for both diagnostic and therapeutic applications. Magnetic propulsion of an untethered device carrying a magnetic core in it is one of the promising methods to navigate the device. MRI gradients coils are thought to be suitable for navigating the device since they are capable of magnetic propulsion in any direction while providing magnetic resonance images. For precise navigation of the device, especially in the peripheral region of the gradient coils, the concomitant gradient fields, as well as the linear gradient fields in the main magnetic field direction, should be considered in driving the gradient coils. For simple gradient coil configurations, the Maxwell coil in the z-direction and the Golay coil in the x- and y-directions, we have calculated the magnetic force fields, which are not necessarily the same as the conventional linear gradient fields of MRI. Using the calculated magnetic force fields, we have synthesized gradient waveforms to navigate the device along a desired path

  20. Effect of Opalescence(®) bleaching gels on the elution of bulk-fill composite components.

    Science.gov (United States)

    Schuster, Lena; Reichl, Franz-Xaver; Rothmund, Lena; He, Xiuli; Yang, Yang; Van Landuyt, Kirsten L; Kehe, Kai; Polydorou, Olga; Hickel, Reinhard; Högg, Christof

    2016-02-01

    Bleaching treatments can affect release of components from conventional composites. In this continuing study the influence of two different bleaching gels on the elution of bulk-fill composite components was investigated. The composites Tetric EvoCeram(®) Bulk Fill, QuiXFil™ and X-tra fil were treated with the bleaching gels Opalescence PF 15% (PF 15%) for 5 h and PF 35% (PF 35%) for 30 min and then stored in methanol and water for 24 h and 7 d. The eluates were analyzed by gas chromatography/mass spectrometry (GC/MS). Unbleached specimens were used as control group. A total of 7 different elutable substances have been identified from the investigated composites after bleaching-treatment. Three of them were methacrylates: 2-hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA) and trimethylolpropane trimethacrylate (TMPTMA). Compared to the unbleached controls an increase in elution after PF 15%-treatment of following compounds was found: HEMA (Tetric EvoCeram(®) Bulk Fill), TEGDMA (QuiXFil™, X-tra fil) and 4-N,N-dimethylaminobenzoic acid butyl ethoxy ester (DMABEE) (Tetric EvoCeram(®) Bulk Fill, QuiXFil™, X-tra fil). Following compounds showed a reduction in elution after PF 35%-treatment compared to controls: TEGDMA (QuiXFil™) and DMABEE (Tetric EvoCeram(®) Bulk Fill). The highest concentration of HEMA was 0.22 mmol/l (Tetric EvoCeram(®) Bulk Fill, methanol, 7 d, PF 15%), the highest concentration of TEGDMA was 0.3 mmol/l (X-tra fil, water, 7 d, PF 15%) and the highest concentration of DMABEE was 0.05 mmol/l (QuiXFil™, water, 7 d, PF 35%). PF 15% and PF 35% can lead to reduced and/or increased elution of some bulk-fill components, compared to unbleached bulk-fill composites. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  1. Establishing conditions for the storage and elution of rabies virus RNA using FTA(®) cards.

    Science.gov (United States)

    Sakai, Takeo; Ishii, Ayako; Segawa, Takao; Takagi, Yukihiko; Kobayashi, Yuki; Itou, Takuya

    2015-04-01

    The Flinders Technology Associates filter paper cards (FTA(®) cards) can be used to store nucleic acid from various samples and are easily portable. However, RNA is physicochemically unstable compared with DNA, and appropriate methods have not been established for storage and extraction of RNA from FTA(®) cards. The present study investigated the optimum conditions for storage and elution of viral RNA (vRNA) using rabies virus (RABV) applied to FTA(®) cards. When TE buffer was used, the elution rates of vRNA increased with the length of the elution time. When the cards were stored at -80 °C or -20 °C, vRNA was stable over 3 months. Degradation of vRNAs occurred following storage at 4 °C and room temperature, suggesting that RNA should be extracted from cards as soon as possible if no freezer is available. When we tried to amplify vRNA from RABV-infected animal brains applied to FTA(®) cards and stored at -80 °C for 6 months, we did not detect any amplified products with the primer set for 964 bp of RABV N gene. However, we were able to detect amplified products by increasing the elution time of vRNA from FTA(®) cards from 30 min to 24 hr or by changing the primer sets to amplify 290 bp of N gene. Thus, we recommend extending the elution time for damaged or low concentration samples in FTA(®) cards.

  2. Denaturing gradient gel electrophoresis

    International Nuclear Information System (INIS)

    Kocherginskaya, S.A.; Cann, I.K.O.; Mackie, R.I.

    2005-01-01

    It is worthwhile considering that only some 30 species make up the bulk of the bacterial population in human faeces at any one time based on the classical cultivation-based approach. The situation in the rumen is similar. Thus, it is practical to focus on specific groups of interest within the complex community. These may be the predominant or the most active species, specific physiological groups or readily identifiable (genetic) clusters of phylogenetically related organisms. Several 16S rDNA fingerprinting techniques can be invaluable for selecting and monitoring sequences or phylogenetic groups of interest and are described below. Over the past few decades, considerable attention was focussed on the identification of pure cultures of microbes on the basis of genetic polymorphisms of DNA encoding rRNA such as ribotyping, amplified fragment length polymorphism and randomly amplified polymorphic DNA. However, many of these methods require prior cultivation and are less suitable for use in analysis of complex mixed populations although important in describing cultivated microbial diversity in molecular terms. Much less attention was given to molecular characterization of complex communities. In particular, research into diversity and community structure over time has been revolutionized by the advent of molecular fingerprinting techniques for complex communities. Denaturing or temperature gradient gel electrophoresis (DGGE/TGGE) methods have been successfully applied to the analysis of human, pig, cattle, dog and rodent intestinal populations

  3. Percutaneous coronary intervention with second-generation paclitaxel-eluting stents versus everolimus-eluting stents in United States contemporary practice (REWARDS TLX Trial).

    Science.gov (United States)

    Waksman, Ron; Ghali, Magdi; Goodroe, Randy; Ryan, Thomas; Turco, Mark; Ring, Michael; McGarry, Thomas; Dobies, David; Shammas, Nicolas; Steinberg, Daniel H; Swymelar, Stacy; Kaneshige, Kimberly; Torguson, Rebecca

    2012-10-15

    Registry Experience at the Washington Hospital Center, DES - Taxus Liberte Versus Xience V (REWARDS TLX) is a physician-initiated, retrospective, real-world, multicenter, observational study for all patients >18 years of age subjected to percutaneous coronary intervention with everolimus-eluting stents (EESs) or paclitaxel-eluting stents (PESs). Outcomes of patients receiving a TAXUS Liberté or XIENCE V drug-eluting stent were compared. Baseline clinical, procedural, and follow-up data at 12 months were collected from 10 clinical centers by an electronic data capture system. The study's primary end point was major adverse cardiac events: a composite of all-cause death, Q-wave myocardial infarction, target vessel revascularization, and stent thrombosis. The trial is registered with http://www.clinicaltrials.gov (NCT01134159). Data were entered for 1,195 patients (PES, n = 595; EES, n = 600). Baseline clinical characteristics were similar except for higher dyslipidemia, systemic hypertension, and family history of coronary artery disease in the EES group. In-hospital outcome was similar between groups, with an overall in-hospital stent thrombosis rate of 0.2%. The primary end point at 12 months was similar (EES 7.8% vs 10.8%, p = 0.082). Overall stent thrombosis rate was lower in the EES group (0.3% vs 1.2%, respectively, p = 0.107); however, target lesion revascularization was similar (PES, hazard ratio 1.46, 95% confidence interval 0.98 to 2.19, p = 0.064). There was no difference in overall mortality between groups. In conclusion, second-generation EESs and PESs demonstrated similar efficacy and safety profiles for broadened patient and lesion subsets compared to a selected population from the pivotal trials. However, for composite efficacy and safety end points, EESs outperformed second-generation PESs. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Characterization of gradient control systems

    NARCIS (Netherlands)

    Cortés, Jorge; van der Schaft, Arjan; Crouch, Peter E.

    2005-01-01

    Given a general nonlinear affine control system with outputs and a torsion-free affine connection defined on its state space, we investigate the gradient realization problem: we give necessary and sufficient conditions under which the control system can be written as a gradient control system

  5. Characterization of Gradient Control Systems

    NARCIS (Netherlands)

    Cortés, Jorge; Schaft, Arjan van der; Crouch, Peter E.

    2005-01-01

    Given a general nonlinear affine control system with outputs and a torsion-free affine connection defined on its state space, we investigate the gradient realization problem: we give necessary and sufficient conditions under which the control system can be written as a gradient control system

  6. Sobolev gradients and differential equations

    CERN Document Server

    Neuberger, J W

    2010-01-01

    A Sobolev gradient of a real-valued functional on a Hilbert space is a gradient of that functional taken relative to an underlying Sobolev norm. This book shows how descent methods using such gradients allow a unified treatment of a wide variety of problems in differential equations. For discrete versions of partial differential equations, corresponding Sobolev gradients are seen to be vastly more efficient than ordinary gradients. In fact, descent methods with these gradients generally scale linearly with the number of grid points, in sharp contrast with the use of ordinary gradients. Aside from the first edition of this work, this is the only known account of Sobolev gradients in book form. Most of the applications in this book have emerged since the first edition was published some twelve years ago. What remains of the first edition has been extensively revised. There are a number of plots of results from calculations and a sample MatLab code is included for a simple problem. Those working through a fair p...

  7. Electric field gradients in metals

    International Nuclear Information System (INIS)

    Schatz, G.

    1979-01-01

    A review of the recent works on electric field gradient in metals is given. The main emphasis is put on the temperature dependence of the electric field gradient in nonmagnetic metals. Some methods of investigation of this effect using nuclear probes are described. One of them is nuclear accoustic resonance method. (S.B.)

  8. Semiautomated system for the production and analysis of sucrose density gradients

    International Nuclear Information System (INIS)

    Lange, C.S.; Liberman, D.F.

    1974-01-01

    A semiautomated system in DNA damage studies permitting considerable accuracy, speed, and reproducibility in the making and fractionation of sucrose density gradients is described. The system consists of a modified Beckman gradient forming device that makes six gradients simultaneously and delivers them into six 12.5 ml polyallomer centrifuge tubes in such a manner that new material is continuously added to the meniscus of the gradient. The gradients are fractionated three at a time and up to 100 fractions per gradient can be collected automatically directly into scintillation vials with a choice of drop counting or time mode with rinse and automatic addition of scintillation fluid to each vial. The system can process up to six gradients per hour but centrifugation time is usually the limiting factor. With neutral sucrose gradients, sharp, reproducible, monodisperse peaks containing up to 100 percent of the gradient radioactivity are usually obtained but a smaller monodisperse peak containing as little as 3.5 percent of the gradient radioactivity can be detected under conditions where some pairs of molecules might tangle or dimerize. The resolution and reproducibility of this system when used with neutral sucrose gradients is at least the equal if not superior to that commonly claimed for alkaline sucrose gradients. (U.S.)

  9. Multi-Mode Cavity Accelerator Structure

    International Nuclear Information System (INIS)

    Jiang, Yong; Hirshfield, Jay Leonard

    2016-01-01

    This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10"-"7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise Δ T. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field E_s_u_r"m"a"x< 260 MV/m and pulsed surface heating Δ T"m"a"x< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power - as compared with operation at the same acceleration gradient using only the fundamental mode.

  10. Multi-Mode Cavity Accelerator Structure

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Yong [Yale Univ., New Haven, CT (United States); Hirshfield, Jay Leonard [Omega-P R& D, Inc., New Haven, CT (United States)

    2016-11-10

    This project aimed to develop a prototype for a novel accelerator structure comprising coupled cavities that are tuned to support modes with harmonically-related eigenfrequencies, with the goal of reaching an acceleration gradient >200 MeV/m and a breakdown rate <10-7/pulse/meter. Phase I involved computations, design, and preliminary engineering of a prototype multi-harmonic cavity accelerator structure; plus tests of a bimodal cavity. A computational procedure was used to design an optimized profile for a bimodal cavity with high shunt impedance and low surface fields to maximize the reduction in temperature rise ΔT. This cavity supports the TM010 mode and its 2nd harmonic TM011 mode. Its fundamental frequency is at 12 GHz, to benchmark against the empirical criteria proposed within the worldwide High Gradient collaboration for X-band copper structures; namely, a surface electric field Esurmax< 260 MV/m and pulsed surface heating ΔTmax< 56 °K. With optimized geometry, amplitude and relative phase of the two modes, reductions are found in surface pulsed heating, modified Poynting vector, and total RF power—as compared with operation at the same acceleration gradient using only the fundamental mode.

  11. The geomagnetic field gradient tensor

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Olsen, Nils

    2012-01-01

    We develop the general mathematical basis for space magnetic gradiometry in spherical coordinates. The magnetic gradient tensor is a second rank tensor consisting of 3 × 3 = 9 spatial derivatives. Since the geomagnetic field vector B is always solenoidal (∇ · B = 0) there are only eight independent...... tensor elements. Furthermore, in current free regions the magnetic gradient tensor becomes symmetric, further reducing the number of independent elements to five. In that case B is a Laplacian potential field and the gradient tensor can be expressed in series of spherical harmonics. We present properties...... of the magnetic gradient tensor and provide explicit expressions of its elements in terms of spherical harmonics. Finally we discuss the benefit of using gradient measurements for exploring the Earth’s magnetic field from space, in particular the advantage of the various tensor elements for a better determination...

  12. Comparison of everolimus- and paclitaxel-eluting stents in patients with acute and stable coronary syndromes: pooled results from the SPIRIT (A Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) and COMPARE (A Trial of Everolimus-Eluting Stents and Paclitaxel-Eluting Stents for Coronary Revascularization in Daily Practice) Trials.

    Science.gov (United States)

    Planer, David; Smits, Pieter C; Kereiakes, Dean J; Kedhi, Elvin; Fahy, Martin; Xu, Ke; Serruys, Patrick W; Stone, Gregg W

    2011-10-01

    This study sought to compare the clinical outcomes of everolimus-eluting stents (EES) versus paclitaxel-eluting stents (PES) in patients with acute coronary syndromes (ACS) and stable coronary artery disease (CAD). Although randomized trials have shown superiority of EES to PES, the safety and efficacy of EES in ACS is unknown. We performed a patient-level pooled analysis from the prospective, randomized SPIRIT (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) II, III, IV, and COMPARE (A Trial of Everolimus-Eluting Stents and Paclitaxel-Eluting Stents for Coronary Revascularization in Daily Practice) trials in which 2,381 patients with ACS and 4,404 patients with stable CAD were randomized to EES or to PES. Kaplan-Meier estimates of death, myocardial infarction (MI), ischemia-driven target lesion revascularization, and stent thrombosis were assessed at 2 years and stratified by clinical presentation (ACS vs. stable CAD). At 2 years, patients with ACS compared with stable CAD had higher rates of death (3.2% vs. 2.4%, hazard ratio [HR]: 1.37 [95% confidence interval (CI): 1.02 to 1.85], p = 0.04) and MI (4.9% vs. 3.4%, HR: 1.45 [95% CI: 1.14 to 1.85], p = 0.02). In patients with ACS, EES versus PES reduced the rate of death or MI (6.6% vs. 9.3%, HR: 0.70 [95% CI: 0.52 to 0.94], p = 0.02), stent thrombosis (0.7% vs. 2.9%, HR: 0.25 [95% CI: 0.12 to 0.52], p = 0.0002), and ischemia-driven target lesion revascularization (4.7% vs. 6.2%, HR: 0.69 [95% CI: 0.48 to 0.99], p = 0.04). In patients with stable CAD, EES reduced the rate of death or MI (4.5% vs. 7.1%, HR: 0.62 [95% CI: 0.48 to 0.80], p = 0.0002), stent thrombosis (0.7% vs. 1.8%, HR: 0.34 [95% CI: 0.19 to 0.62], p = 0.0002), and ischemia-driven target lesion revascularization (3.9% vs. 6.9%, HR: 0.55 [95% CI: 0.42 to 0.73], p SPIRIT II]; NCT00180310; SPIRIT III: A Clinical Evaluation of the Investigational Device XIENCE V Everolimus Eluting Coronary Stent System [EECSS] in the

  13. Degree of conversion and monomer elution of CQ/amine and TPO adhesives.

    Science.gov (United States)

    Pongprueksa, Pong; Miletic, Vesna; Janssens, Henriette; Van Landuyt, Kirsten L; De Munck, Jan; Godderis, Lode; Van Meerbeek, Bart

    2014-06-01

    To evaluate the effect of photo-initiator on the degree of conversion (DC) and elution of Bis-GMA and HEMA for 8 one-step adhesive formulations. We used Scotchbond Universal ('SBU-CQ/amine_4.0', 3M ESPE), containing about 2wt% camphorquinone (CQ) and 2wt% ethyl-4-dimethylamino benzoate (EDMAB), an experimental 'SBU-TPO_2.1' version, containing 2.1wt% diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), and 6 experimental LUB adhesives (Kuraray Noritake), namely 'LUB-CQ/amine_0.7', 'LUB-CQ/amine_1.4', 'LUB-CQ/amine_4.0', 'LUB-TPO_0.35', 'LUB-TPO_0.7' and 'LUB-TPO_2.0', respectively containing 0.35wt% CQ and 0.35wt% EDMAB, 0.7wt% CQ and 0.7wt% EDMAB, 2.0wt% CQ and 2.0wt% EDMAB, 0.35wt% TPO, 0.7wt% TPO, and 2.0wt% TPO. DC was measured using micro-Raman spectroscopy. Additional specimens were immersed in ethanol for 24h to determine the elution of Bis-GMA and HEMA using HPLC. DC of the respective SBU and LUB adhesives was alike at high photo-initiator concentration. At low concentration, TPO was significantly more efficient than CQ/amine (LUB adhesives only). A statistically significant positive photo-initiator concentration effect on DC was noted for both CQ/amine and TPO (LUB adhesives only). A statistically significant inverse photo-initiator concentration effect on HEMA elution was noted for both the CQ/amine- and TPO-containing LUB adhesives. A significantly strong correlation was found between DC and Bis-GMA elution (R(2)=0.744, p=0.026), and between DC and HEMA elution (R(2)=0.913, p=0.002) for the LUB adhesives. The photo-initiator kind and concentration affect DC and the Bis-GMA/HEMA elution. TPO can be used as an alternative photo-initiator for CQ/amine. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  14. Long-term Outcomes of Paclitaxel-Eluting Versus Sirolimus-Eluting Stent for Percutaneous Coronary Intervention: A Meta-Analysis

    International Nuclear Information System (INIS)

    Kong, J.; Liu, P.; Fan, X.; Wen, J.; Zhang, J.; Zhen, Y.; Li, J.; Cui, Y.; Zheng, X.; Ye, Z.

    2017-01-01

    The relative long-term efficacy and safety of sirolimus-eluting stents (SES) compared with paclitaxel-eluting stents (PES) in multiple comparative studies remains controversial. This report evaluates 29 randomized trials with 18,379 patients in whom long-term (more than 1 year) outcomes were evaluated. The primary outcomes were target lesion revascularization (TLR) and the secondary end points were death, cardiac death, myocardial infarction (MI), major adverse cardiac events (MACEs), target vessel revascularization (TVR)and stent thrombosis (ST). In comparison with PES, SES significantly reduced the long-term risk of TLR (RR=0.68; 95% CI=0.57 to 0.80, p<0.001), TVR (RR=0.69; 95% CI= 0.60 to 0.79, p<0.001) and MACE (RR=0.82; 95% CI= 0.77 to 0.88, p<0.001), while there were no significant difference with respect to death, cardiac death, MI and ST between the two groups. SES performance was significantly better for reducing the former three outcomes and comparable for the majority of the secondary end points when compared against PES. (author)

  15. MODIFIED ARMIJO RULE ON GRADIENT DESCENT AND CONJUGATE GRADIENT

    Directory of Open Access Journals (Sweden)

    ZURAIDAH FITRIAH

    2017-10-01

    Full Text Available Armijo rule is an inexact line search method to determine step size in some descent method to solve unconstrained local optimization. Modified Armijo was introduced to increase the numerical performance of several descent algorithms that applying this method. The basic difference of Armijo and its modified are in existence of a parameter and estimating the parameter that is updated in every iteration. This article is comparing numerical solution and time of computation of gradient descent and conjugate gradient hybrid Gilbert-Nocedal (CGHGN that applying modified Armijo rule. From program implementation in Matlab 6, it's known that gradient descent was applying modified Armijo more effectively than CGHGN from one side: iteration needed to reach some norm of the gradient  (input by the user. The amount of iteration was representing how long the step size of each algorithm in each iteration. In another side, time of computation has the same conclusion.

  16. Efficient inclusion body processing using chemical extraction and high gradient magnetic fishing

    DEFF Research Database (Denmark)

    Heebøll-Nielsen, Anders; Choe, W.S.; Middelberg, A.P.J.

    2003-01-01

    of the product-loaded supports with the aid of high gradient magnetic fields. The manufacture and testing of two types of micron-sized nonporous superparamagnetic metal chelator particles derivatized with iminodiacetic acid is described. In small-scale adsorption studies conducted with a hexahistidine tagged...... at a 60-fold increased scale using the high gradient magnetic fishing (HGMF) system to collect loaded Cu2+-chelator particles following batch adsorption of L1. Over 70% of the initial Ll present was recovered within the HGMF rig in a highly clarified form in two batch elution cycles with an overall......In this study we introduce a radical new approach for the recovery of proteins expressed in the form of inclusion bodies, involving W chemical extraction from the host cells, (ii) adsorptive capture of the target protein onto small magnetic adsorbents, and (iii) subsequent rapid collection...

  17. Linear local stability of electrostatic drift modes in helical systems

    International Nuclear Information System (INIS)

    Yamagishi, O.; Nakajima, N.; Sugama, H.; Nakamura, Y.

    2003-01-01

    We investigate the stability of the drift wave in helical systems. For this purpose, we solve the linear local gyrokinetic-Poisson equation, in the electrostatic regime. As a model of helical plasmas, Large helical Device (LHD) is considered. The equation we apply is rather exact in the framework of linear gyrokinetic theory, where only the approximation is the ballooning representation. In this paper, we consider only collisionless cases. All the frequency regime can be naturally reated without any assumptions, and in such cases, ion temperature gradient modes (ITG), trapped electron modes (TEM), and electron temperature gradient modes (ETG) are expected to become unstable linearly independently. (orig.)

  18. Change of transport at L- and H-mode transition

    International Nuclear Information System (INIS)

    Itoh, Sanae-I; Itoh, Kimitaka.

    1990-01-01

    A new refined model of the L-mode and H-mode transition in tokamaks is presented based on the bifurcation of the radial electric field, E r , near edge. The radial gradient of E r is newly introduced to explain the sudden change of fluctuations as well as plasma fluxes at the onset of transition. This model predicts that the L-to H-mode transition is associated with the decrease of dE r /dr causing reduction of particle and energy fluxes at critical gradient. (author)

  19. Edge kink/ballooning mode stability in tokamaks with separatrix

    International Nuclear Information System (INIS)

    Medvedev, S Yu; Martynov, A A; Martin, Y R; Sauter, O; Villard, L

    2006-01-01

    Stability limits against external kink modes driven by large current density and pressure gradient values in the pedestal region are investigated for tokamak plasmas with separatrix. Stability diagrams for modes with different toroidal wave numbers under variations of pressure gradient and current density in the pedestal region are presented for several equilibrium configurations related to TCV. A scaling for the toroidal wave number of the most unstable mode is proposed. The influence of the plasma cross-section geometry on the stability limits is discussed

  20. Combining Step Gradients and Linear Gradients in Density.

    Science.gov (United States)

    Kumar, Ashok A; Walz, Jenna A; Gonidec, Mathieu; Mace, Charles R; Whitesides, George M

    2015-06-16

    Combining aqueous multiphase systems (AMPS) and magnetic levitation (MagLev) provides a method to produce hybrid gradients in apparent density. AMPS—solutions of different polymers, salts, or surfactants that spontaneously separate into immiscible but predominantly aqueous phases—offer thermodynamically stable steps in density that can be tuned by the concentration of solutes. MagLev—the levitation of diamagnetic objects in a paramagnetic fluid within a magnetic field gradient—can be arranged to provide a near-linear gradient in effective density where the height of a levitating object above the surface of the magnet corresponds to its density; the strength of the gradient in effective density can be tuned by the choice of paramagnetic salt and its concentrations and by the strength and gradient in the magnetic field. Including paramagnetic salts (e.g., MnSO4 or MnCl2) in AMPS, and placing them in a magnetic field gradient, enables their use as media for MagLev. The potential to create large steps in density with AMPS allows separations of objects across a range of densities. The gradients produced by MagLev provide resolution over a continuous range of densities. By combining these approaches, mixtures of objects with large differences in density can be separated and analyzed simultaneously. Using MagLev to add an effective gradient in density also enables tuning the range of densities captured at an interface of an AMPS by simply changing the position of the container in the magnetic field. Further, by creating AMPS in which phases have different concentrations of paramagnetic ions, the phases can provide different resolutions in density. These results suggest that combining steps in density with gradients in density can enable new classes of separations based on density.

  1. Block-conjugate-gradient method

    International Nuclear Information System (INIS)

    McCarthy, J.F.

    1989-01-01

    It is shown that by using the block-conjugate-gradient method several, say s, columns of the inverse Kogut-Susskind fermion matrix can be found simultaneously, in less time than it would take to run the standard conjugate-gradient algorithm s times. The method improves in efficiency relative to the standard conjugate-gradient algorithm as the fermion mass is decreased and as the value of the coupling is pushed to its limit before the finite-size effects become important. Thus it is potentially useful for measuring propagators in large lattice-gauge-theory calculations of the particle spectrum

  2. Advantages of novel BioMimeTM Sirolimus Eluting Coronary Stent system. Moving towards biomimicry.

    Science.gov (United States)

    Upendra, K; Sanjeev, B

    2012-02-01

    Since the first reported use of percutaneous transluminal coronary angioplasty (PTCA), advancements in interventional cardiology arena have been fast paced. Within the last ten years, these developments have been exponential. Developers & clinicians are fast adapting from the learning curve awarded by the time course of DES evolution. In that light BioMimeTM Sirolimus Eluting Coronary Stent comes as a fresh thought in taking stents towards a biomimicry concept. The stent is built on an ultra-low strut thickness (65 µm) cobalt chromium stent platform, using an intelligent hybrid of close and open cells allowing for morphology mediated expansion, employs a well known anti-proliferative - Sirolimus that elutes from a biodegradable co-polymer formulation in 30 days and ensures high coating integrity and low coating thickness of 2 µm. The resultant stent demonstrates almost 100% endothelialization at 30 days in preclinical model and zero percent MACE >18 months in the primary efficacy and safety clinical study.

  3. Progress in the study of drug-eluting intra-stent thrombosis

    International Nuclear Information System (INIS)

    Guo Zhifu; Zheng Xing; Qin Yongwen

    2007-01-01

    Durg-eluting stent has been regarded as the milestone in the history of PCI for their efficiency in the prevention of coronary arterial restenosis after percutaneous coronary intervention. But unfortunately intra-stent thrombosis continues to be a serious complication of contemporary DES use. The incidence of drug-eluting stents thrombosis is at least not lower than that of bare metal stents at present. The clinical consequences of stent thrombosis are frequently catastrophic, including death in 40% to 50% of the cases or major myocardial infarction in 60% to 70%. Premature discontinuation of standard antiplatelet therapy is by far the most important predictor of stent thrombosis with DES and other predictors included renal failure, diabetes, bifurcation lesions, multiple lesions or multivessel disease, long stents, female, advanced age, stent underexpansion and residual stenosis etc. The delayed endothelialization may be the underling mechanism of DES thrombosis. (authors)

  4. Safety and Efficacy of Everolimus- Versus Sirolimus-Eluting Stents

    DEFF Research Database (Denmark)

    Jensen, Lisette Okkels; Thayssen, Per; Christiansen, Evald Høj

    2016-01-01

    BACKGROUND: Long-term safety and efficacy for everolimus-eluting stents (EES) versus those of sirolimus-eluting stents (SES) are unknown. OBJECTIVES: This study compared 5-year outcomes for EES with those for SES from the SORT OUT IV (Scandinavian Organization for Randomized Trials with Clinical...... rate was lower with EES (HR: 0.71, 95% CI: 0.55 to 0.90; p = 0.006; p interaction = 0.12). Definite stent thrombosis was lower with EES (0.4%) than with SES (2.0%; HR: 0.18, 95% CI: 0.07 to 0.46), with a lower risk of very late definite stent thrombosis in the EES group (0.2% vs. 1.4%, respectively; HR...... in Non-selected Patients With Coronary Heart Disease [SORT OUT IV]; NCT00552877)....

  5. Transarterial chemoembolization with drug-eluting beads for hepatocellular carcinoma: its research progress

    International Nuclear Information System (INIS)

    Zhao Yan; Han Guohong; Bai Wei; Fan Daiming

    2012-01-01

    Transarterial chemoembolization (TACE) has been the main treatment for patients with intermediate-stage hepatocellular carcinoma (HCC). However, the clinical application of TACE is limited due to the technical deficiencies, such as uncontrolled local drug delivery and systemic toxicity. Recently, the new drug-eluting beads (DEB), loading with doxorubicin, have be used in the TACE procedures. This new technique can not only maintain the local drug level for quite a long time and thus get a higher objective response, but also decrease the systemic toxicity. Transarterial chemoembolization with drug-eluting beads (DEB-TACE) have already been widely used abroad, and more related clinical trials are underway to clarify its advantages. This paper aims to make a comprehensive review in the respects of its characteristics and the latest research progress in DEB-TACE. (authors)

  6. High temperature L- and H-mode confinement in JET

    International Nuclear Information System (INIS)

    Balet, B.; Boyd, D.A.; Campbell, D.J.

    1990-01-01

    The energy confinement properties of low density, high ion temperature L- and H-mode plasmas are investigated. For L-mode plasmas it is shown that, although the global confinement is independent of density, the energy confinement in the central region is significantly better at low densities than at higher densities. The improved confinement appears to be associated with the steepness of the density gradient. For the H-mode phase, although the confinement at the edge is dramatically improved, which is once again associated with the steep density gradient in the edge region, the central confinement properties are essentially the same as for the standard L-mode. The results are compared in a qualitative manner with the predictions of the ion temperature gradient instability theory and appear to be in disagreement with some aspects of this theory. (author). 13 refs, 15 figs

  7. Development of epigallocatechin gallate-eluting polymeric stent and its physicochemical, biomechanical and biological evaluations

    International Nuclear Information System (INIS)

    Han, Dong-Wook; Lee, Jun Jae; Jung, Duk-Young; Park, Jong-Chul; Hyon, Suong-Hyu

    2009-01-01

    Localized drug delivery from drug-eluting stents has been accepted as one of the most promising treatment methods for preventing restenosis after stenting. However, hypersensitivity reactions caused by their nonresorbable polymer coatings and bare-metal stents may result in serious clinical sequelae. Epigallocatechin-3-O-gallate (EGCG), the predominant catechin from tea, has been shown to exert anti-thrombotic, anti-inflammatory and anti-proliferative activities. In this study, it was hypothesized that sustainedly released EGCG from biodegradable poly(lactide-co-ε-caprolactone, PLCL) would suppress the proliferation of vascular smooth muscle cells (VSMCs). EGCG-releasing PLCL (E-PLCL) was prepared by blending PLCL with EGCG. The surface morphology, roughness and melting temperature of PLCL were not changed despite EGCG addition. EGCG was uniformly dispersed into E-PLCL and sustainedly released for periods up to 7 days by controlled diffusion rather than PLCL degradation. Moreover, EGCG did not affect tensile strength at break, but significantly increased the elastic modulus of PLCL. The proliferation of VSMCs onto E-PLCL was significantly suppressed although the cell attachment onto E-PLCL had been higher than that onto PLCL. On the other hand, EGCG-eluting polymeric stents were prepared with neither cracks nor webbings between struts, and their structural integrity was maintained without delamination or destruction. These results suggest that E-PLCL can be potentially applied for fabricating an EGCG-eluting vascular stent, namely an EGCG-eluting polymeric stent, or even an EGCG-releasing polymer-coated metal stent, to prevent thrombosis, inflammation and in-stent restenosis.

  8. Development of epigallocatechin gallate-eluting polymeric stent and its physicochemical, biomechanical and biological evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Han, Dong-Wook [Department of Nanomedical Engineering, College of Nanoscience and Nanotechnology, Pusan National University, Busan 609-735 (Korea, Republic of); Lee, Jun Jae [Division of Advanced Fibro-Science, Kyoto Institute of Technology, Kyoto 606-8585 (Japan); Jung, Duk-Young [Senior Products Industrial Center, Busan Techno-Park, Busan-617-030 (Korea, Republic of); Park, Jong-Chul [Cellbiocontrol Laboratory, Department of Medical Engineering, Yonsei University College of Medicine, Seoul 120-752 (Korea, Republic of); Hyon, Suong-Hyu, E-mail: nanohan@pusan.ac.k, E-mail: biogen@frontier.kyoto-u.ac.j [Department of Medical Simulation Engineering, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507 (Japan)

    2009-08-15

    Localized drug delivery from drug-eluting stents has been accepted as one of the most promising treatment methods for preventing restenosis after stenting. However, hypersensitivity reactions caused by their nonresorbable polymer coatings and bare-metal stents may result in serious clinical sequelae. Epigallocatechin-3-O-gallate (EGCG), the predominant catechin from tea, has been shown to exert anti-thrombotic, anti-inflammatory and anti-proliferative activities. In this study, it was hypothesized that sustainedly released EGCG from biodegradable poly(lactide-co-epsilon-caprolactone, PLCL) would suppress the proliferation of vascular smooth muscle cells (VSMCs). EGCG-releasing PLCL (E-PLCL) was prepared by blending PLCL with EGCG. The surface morphology, roughness and melting temperature of PLCL were not changed despite EGCG addition. EGCG was uniformly dispersed into E-PLCL and sustainedly released for periods up to 7 days by controlled diffusion rather than PLCL degradation. Moreover, EGCG did not affect tensile strength at break, but significantly increased the elastic modulus of PLCL. The proliferation of VSMCs onto E-PLCL was significantly suppressed although the cell attachment onto E-PLCL had been higher than that onto PLCL. On the other hand, EGCG-eluting polymeric stents were prepared with neither cracks nor webbings between struts, and their structural integrity was maintained without delamination or destruction. These results suggest that E-PLCL can be potentially applied for fabricating an EGCG-eluting vascular stent, namely an EGCG-eluting polymeric stent, or even an EGCG-releasing polymer-coated metal stent, to prevent thrombosis, inflammation and in-stent restenosis.

  9. Hepatic Arterial Chemoembolization Using Drug-Eluting Beads in Gastrointestinal Neuroendocrine Tumor Metastatic to the Liver

    International Nuclear Information System (INIS)

    Gaur, Shantanu K.; Friese, Jeremy L.; Sadow, Cheryl A.; Ayyagari, Rajasekhara; Binkert, Christoph A.; Schenker, Matthew P.; Kulke, Matthew; Baum, Richard

    2011-01-01

    Purpose: This study was designed to evaluate short ( 3 months) follow-up in patients with metastatic neuroendocrine tumor to the liver who underwent hepatic arterial chemoembolization with drug-eluting beads at a single institution. Methods: Institutional review board approval was obtained for this retrospective review. All patients who were treated with 100–300 or 300–500 μm drug-eluting LC Beads (Biocompatibles, UK) preloaded with doxorubicin (range, 50–100 mg) for GI neuroendocrine tumor metastatic to the liver from June 2004 to June 2009 were included. CT and MRI were evaluated for progression using Response Evaluation Criteria In Solid Tumors (RECIST) or European Association for the Study of the Liver (EASL) criteria. Short-term ( 3 months) imaging response was determined and Kaplan–Meier survival curves were plotted. Results: Thirty-eight drug-eluting bead chemoembolization procedures were performed on 32 hepatic lobes, comprising 21 treatment cycles in 18 patients. All procedures were technically successful with two major complications (biliary injuries). At short-term follow-up (<3 months), 22 of 38 (58%) procedures and 10 of 21 (48%) treatment cycles produced an objective response (OR) with the remainder having stable disease (SD). At intermediate-term follow-up (mean, 445 days; range, 163–1247), 17 of 26 (65%) procedures and 8 of 14 (57%) treatment cycles produced an OR. Probability of progressing was approximately 52% at 1 year with a median time to progression of 419 days. Conclusions: Drug-eluting bead chemoembolization is a reasonable alternative to hepatic arterial embolization and chemoembolization for the treatment of metastatic neuroendocrine tumor to the liver.

  10. Magmaris: a new generation metallic sirolimus-eluting fully bioresorbable scaffold: present status and future perspectives

    OpenAIRE

    Rapetto, Claudio; Leoncini, Massimo

    2017-01-01

    Drug-eluting stents (DES) have reached a high safety and efficacy profile, becoming the best option for percutaneous coronary interventions (PCI) based revascularization. However, despite their optimal performance, a few concerns remain regarding their use, mainly due to permanent caging of the vessels and its consequences, first of all late stent thrombosis (ST). Bioresorbable scaffolds (BRS) aim to overcome these issues. The results achieved in randomized controlled trials (RCT) by the firs...

  11. Posterior reversible leukoencephalopathy syndrome secondary to hepatic transarterial chemoembolization with doxorubicin drug eluting beads

    Science.gov (United States)

    Kistler, C. Andrew; McCall, Joseph Caleb; Ghumman, Saad Sultan; Ali, Ijlal Akbar

    2014-01-01

    Posterior reversible encephalopathy syndrome (PRES) is a rare complication of transarterial chemoembolization (TACE) used to treat liver metastases and has never been reported in a patient with metastatic uveal melanoma (UM) to the liver. We report the first case of PRES secondary to TACE with drug eluting beads (DEBs) loaded with doxorubicin in a 56-year-old woman with metastatic UM to the liver. PMID:24772346

  12. Histologic Assessment of Drug-Eluting Grafts Related to Implantation Site

    Directory of Open Access Journals (Sweden)

    Jean-Christophe Tille

    2016-02-01

    Full Text Available Drug-eluting vascular prostheses represent a new direction in vascular surgery to reduce early thrombosis and late intimal hyperplasia for small calibre grafts. Subcutaneous implantation in rats is a rapid and cost-effective screening model to assess the drug-elution effect and could, to some extent, be useful to forecast results for vascular prostheses. We compared biological and histological responses to scaffolds in different implantation sites. Polycaprolactone (PCL, paclitaxel-loaded PCL (PCL-PTX and dexamethasone-loaded PCL (PCL-DXM electrospun scaffolds were implanted subcutaneously and in an infrarenal abdominal aortic model in rats for up to 12 weeks. At the conclusion of the study, a histological analysis was performed. Cellular graft invasion revealed differences in the progression of cellular infiltration between PCL-PTX and PCL/PCL-DXM groups in both models. Cell infiltration increased over time in the aortic model compared to the subcutaneous model for all groups. Cell counting revealed major differences in fibroblast, macrophage and giant cell graft colonisation in all groups and models over time. Macrophages and giant cells increased in the PCL aortic model; whereas in the subcutaneous model these cell types increased only after three weeks or even decreased in the drug-eluting PCL groups. Other major findings were observed only in the aortic replacement such as extracellular matrix deposition and neo-angiogenesis. The subcutaneous implant model can be used for screening, especially when drug-eluting effects are studied. However, major histological differences were observed in cell type reaction and depth of cell penetration compared to the aortic model. Our results demonstrate that the implantation site is a critical determinant of the biological response.

  13. Everolimus-induced Pneumonitis after Drug-eluting Stent Implantation: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Susumu, E-mail: susumu1029@gmail.com; Kikuchi, Naoshi; Ichikawa, Atsuo; Sano, Go; Satoh, Keita; Sugino, Keishi; Isobe, Kazutoshi; Takai, Yujiro [Toho University School of Medicine, Department of Respiratory Medicine (Japan); Shibuya, Kazutoshi [Toho University School of Medicine, Department of Pathology (Japan); Homma, Sakae [Toho University School of Medicine, Department of Respiratory Medicine (Japan)

    2013-08-01

    Despite the wide use of everolimus as an antineoplastic coating agent for coronary stents to reduce the rate of restenosis, little is known about the health hazards of everolimus-eluting stents (EES). We describe a case of pneumonitis that developed 2 months after EES implantation for angina. Lung pathology demonstrated an organizing pneumonia pattern that responded to corticosteroid therapy. Although the efficacy of EES for ischemic heart disease is well established, EES carries a risk of pneumonitis.

  14. Superconducting multi-cell trapped mode deflecting cavity

    Science.gov (United States)

    Lunin, Andrei; Khabiboulline, Timergali; Gonin, Ivan; Yakovlev, Vyacheslav; Zholents, Alexander

    2017-10-10

    A method and system for beam deflection. The method and system for beam deflection comprises a compact superconducting RF cavity further comprising a waveguide comprising an open ended resonator volume configured to operate as a trapped dipole mode; a plurality of cells configured to provide a high operating gradient; at least two pairs of protrusions configured for lowering surface electric and magnetic fields; and a main power coupler positioned to optimize necessary coupling for an operating mode and damping lower dipole modes simultaneously.

  15. 3-Year Clinical Follow-Up of the RIBS IV Clinical Trial: A Prospective Randomized Study of Drug-Eluting Balloons Versus Everolimus-Eluting Stents in Patients With In-Stent Restenosis in Coronary Arteries Previously Treated With Drug-Eluting Stents.

    Science.gov (United States)

    Alfonso, Fernando; Pérez-Vizcayno, María José; Cuesta, Javier; García Del Blanco, Bruno; García-Touchard, Arturo; López-Mínguez, José Ramón; Masotti, Mónica; Zueco, Javier; Cequier, Angel; Velázquez, Maite; Moreno, Raúl; Mainar, Vicente; Domínguez, Antonio; Moris, Cesar; Molina, Eduardo; Rivero, Fernando; Jiménez-Quevedo, Pilar; Gonzalo, Nieves; Fernández-Pérez, Cristina

    2018-05-28

    This study sought to compare the long-term safety and efficacy of drug-eluting balloons (DEB) and everolimus-eluting stents (EES) in patients with in-stent restenosis (ISR) of drug-eluting stents (DES). Treatment of patients with DES-ISR remains a challenge. The RIBS IV (Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloons vs Everolimus-Eluting Stents) trial is a prospective multicenter randomized clinical trial comparing DEB and EES in patients with DES-ISR. The pre-specified comparison of the 3-year clinical outcomes obtained with these interventions is the main objective of the present study. A total of 309 patients with DES-ISR were randomized to DEB (n = 154) or EES (n = 155). At angiographic follow-up, the in-segment minimal lumen diameter was larger in the EES arm (2.03 ± 0.7 mm vs. 1.80 ± 0.6 mm; p 1 year) target lesion revascularization (2.6% vs. 4%) and target vessel revascularization (4% vs. 6.6%) was similar in the 2 arms. Rates of cardiac death (3.9% vs. 3.2%), myocardial infarction (2.6% vs. 4.5%), and stent thrombosis (1.3% vs. 2.6%) at 3 years were also similar in both arms. The 3-year clinical follow-up of this randomized clinical trial demonstrates that in patients with DES-ISR, EES reduce the need for repeat interventions compared with DEB. (Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloons vs Everolimus-Eluting Stents [RIBS IV]; NCT01239940). Published by Elsevier Inc.

  16. Incidence and Potential Mechanism(s) of Post-Procedural Rise of Cardiac Biomarker in Patients With Coronary Artery Narrowing After Implantation of an Everolimus-Eluting Bioresorbable Vascular Scaffold or Everolimus-Eluting Metallic Stent

    DEFF Research Database (Denmark)

    Ishibashi, Yuki; Muramatsu, Takashi; Nakatani, Shimpei

    2015-01-01

    OBJECTIVES: This study sought to evaluate the mechanism of post-procedural cardiac biomarker (CB) rise following device implantation. BACKGROUND: A fully bioresorbable Absorb scaffold, compared with everolimus-eluting metallic stents (EES), might be associated with a higher incidence...

  17. Fano resonances from gradient-index metamaterials.

    Science.gov (United States)

    Xu, Yadong; Li, Sucheng; Hou, Bo; Chen, Huanyang

    2016-01-27

    Fano resonances - resonant scattering features with a characteristic asymmetric profile - have generated much interest, due to their extensive and valuable applications in chemical or biological sensors, new types of optical switches, lasers and nonlinear optics. They have been observed in a wide variety of resonant optical systems, including photonic crystals, metamaterials, metallic gratings and nanostructures. In this work, a waveguide structure is designed by employing gradient-index metamaterials, supporting strong Fano resonances with extremely sharp spectra. As the changes in the transmission spectrum originate from the interaction of guided modes from different channels, instead of resonance structures or metamolecules, the Fano resonances can be observed for both transverse electric and transverse magnetic polarizations. These findings are verified by fine agreement with analytical calculations and experimental results at microwave, as well as simulated results at near infrared frequencies.

  18. Spatial gradient tuning in metamaterials

    Science.gov (United States)

    Driscoll, Tom; Goldflam, Michael; Jokerst, Nan; Basov, Dimitri; Smith, David

    2011-03-01

    Gradient Index (GRIN) metamaterials have been used to create devices inspired by, but often surpassing the potential of, conventional GRIN optics. The unit-cell nature of metamaterials presents the opportunity to exert much greater control over spatial gradients than is possible in natural materials. This is true not only during the design phase but also offers the potential for real-time reconfiguration of the metamaterial gradient. This ability fits nicely into the picture of transformation-optics, in which spatial gradients can enable an impressive suite of innovative devices. We discuss methods to exert control over metamaterial response, focusing on our recent demonstrations using Vanadium Dioxide. We give special attention to role of memristance and mem-capacitance observed in Vanadium Dioxide, which simplify the demands of stimuli and addressing, as well as intersecting metamaterials with the field of memory-materials.

  19. Clinical benefits of drug-eluting stent implantation in septuagenarians with coronary artery disease

    International Nuclear Information System (INIS)

    Fang Yuehua; Shen Weifeng; Zhang Ruiyan; Zhang Jiansheng; Hu Jian; Zhang Xian; Zheng Aifang

    2005-01-01

    Objective: This study evaluated the safety and long-term outcomes of drug-eluting stents in septuagenarians with coronary artery disease. Methods: Two hundred and thirty-nine consecutive patients with coronary artery disease underwent drug-eluting stenting, including 88 patients aged ≥70 years (group A) and 151 aged <70 years (group B). Baseline clinical characteristics, procedural success rate, occurrence of cardiac events during follow-up were recorded and compared between the two groups. Results: Procedural success rate and complications were similar for the two groups. During follow-up, group A had higher recurrence rate of chest pain than group B (23.9% vs. 7.3%, P<0.001), and occurrence of cardiac events was higher in group A than in group B (5.7% vs. 2.7%, P<0.296). There was no significant difference in the frequency of restenosis between the two groups. Conclusions: Drug-eluting stent implantation for septuagenarians with coronary artery disease is safe but may have more recurrence of angina than younger ones during long-term follow-up. (authors)

  20. The elution of certain protein affinity tags with millimolar concentrations of diclofenac.

    Science.gov (United States)

    Baliova, Martina; Juhasova, Anna; Jursky, Frantisek

    2015-12-01

    Diclofenac (2-[(2, 6-dichlorophenyl)amino] benzeneacetic acid) is a sparingly soluble, nonsteroidal anti-inflammatory drug therapeutically acting at low micromolar concentrations. In pH range from 8 to 11, its aqueous solubility can be increased up to 200 times by the presence of counter ions such as sodium. Our protein interaction studies revealed that a millimolar concentration of sodium diclofenac is able to elute glutathione S-transferase (GST), cellulose binding protein (CBD), and maltose binding protein (MBP) but not histidine-tagged or PDZ-tagged proteins from their affinity resins. The elution efficiency of diclofenac is comparable with the eluting agents normally used at similar concentrations. Native gel electrophoresis of sodium diclofenac-treated proteins showed that the interaction is non-covalent and non-denaturing. These results suggest that sodium diclofenac, in addition to its pharmaceutical applications, can also be exploited as a lead for the development of new proteomics reagents. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Elution of Uranium and Calculation of Plate Number on the Column of Silica-TBP

    International Nuclear Information System (INIS)

    Endang Susiantini; Indra Suryawan

    2007-01-01

    Separation process of 99 Mo resulted of irradiated uranyl nitrate with an accelerator as the neutron source by the chromatographic extraction using column containing kiesel gel-TBP will be developed. Kiesel gel (silica) was used as an inert subpart, TBP as a phase stationary and simulated used natural uranyl nitrate of 200-300 g/l with the acidity of 2 N as the mobile phase. The inert support was made by means of kiesel-gel (silica) hydrophobization to change hydrophilic silica to hydrophobic silica, so that it could be impregnated by TBP. Uranium which has been attached to TBP would be eluted by dilute acid at acidity of 0.05; 0.1; 0.2 N HNO 3 ; Warm DW and cool DW. By using 0.1 N HNO 3 eluent and warm DW the uranium attached to silica-TBP could be eluted perfectly and more quickly than the three others eluent. Uranium concentration which were absorbed and eluted were analysed titrimetrically by using titan method and it was used to calculate Plate Number (N). The value of N obtained for the column which the inert support of 8 cm in height, 1 cm in diameter, 10 drops per minute by using of 0.1 N HNO 3 eluent was 300.6. (author)

  2. Investigation of Processes Controlling Elution of Solutes from Nonaqueous Phase Liquid (NAPL) Pools into Groundwater

    Science.gov (United States)

    Seyedabbasi, M.; Pirestani, K.; Holland, S. B.; Imhoff, P. T.

    2005-12-01

    Two major processes influencing the elution of solutes from porous media contaminated with nonaqueous phase liquids (NAPLs) are external mass transfer between the NAPL and groundwater and internal diffusion through NAPL ganglia and pools. There is a relatively large body of literature on the dissolution of single-species NAPLs. Less is known about the rates of elution of compounds dissolving from multicomponent NAPLs. We examined the mass transfer of one solute, 2,3-dimethyl-2-butanol (DMB) - a partitioning tracer, between groundwater and a dense NAPL - trichloroethylene (TCE). Diffusion cell experiments were used to measure the molecular diffusion coefficient of DMB in pure TCE and in porous media contaminated with a TCE pool. Measured diffusion coefficients were compared with empirical correlations (pure TCE) and a parallel resistance model (TCE pool). Based on the results from these analyses, a dimensionless Biot number was derived to express the ratio of the external rate of mass transfer from a NAPL pool to the internal rate of diffusion within the pool, which varies with NAPL saturation and NAPL-water partition coefficient. Biot numbers were then estimated for several laboratory scale experiments involving DMB transport between NAPL pools and groundwater. The estimated Biot numbers were in good agreement with experimental results. The expression for the Biot number developed here may be used to assess the processes controlling the elution of solutes from NAPL pools, which has implications on long-term predictions of solute dissolution from NAPLs in the field.

  3. Application of linear pH gradients for the modeling of ion exchange chromatography: Separation of monoclonal antibody monomer from aggregates.

    Science.gov (United States)

    Kluters, Simon; Wittkopp, Felix; Jöhnck, Matthias; Frech, Christian

    2016-02-01

    The mobile phase pH is a key parameter of every ion exchange chromatography process. However, mechanistic insights into the pH influence on the ion exchange chromatography equilibrium are rare. This work describes a mechanistic model capturing salt and pH influence in ion exchange chromatography. The pH dependence of the characteristic protein charge and the equilibrium constant is introduced to the steric mass action model based on a protein net charge model considering the number of amino acids interacting with the stationary phase. This allows the description of the adsorption equilibrium of the chromatographed proteins as a function of pH. The model parameters were determined for a monoclonal antibody monomer, dimer, and a higher aggregated species based on a manageable set of pH gradient experiments. Without further modification of the model parameters the transfer to salt gradient elution at fixed pH is demonstrated. A lumped rate model was used to predict the separation of the monoclonal antibody monomer/aggregate mixture in pH gradient elution and for a pH step elution procedure-also at increased protein loadings up to 48 g/L packed resin. The presented model combines both salt and pH influence and may be useful for the development and deeper understanding of an ion exchange chromatography separation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Low-gradient aortic stenosis.

    Science.gov (United States)

    Clavel, Marie-Annick; Magne, Julien; Pibarot, Philippe

    2016-09-07

    An important proportion of patients with aortic stenosis (AS) have a 'low-gradient' AS, i.e. a small aortic valve area (AVA gradient (gradient discrepancy raises uncertainty about the actual stenosis severity and thus about the indication for aortic valve replacement (AVR) if the patient has symptoms and/or left ventricular (LV) systolic dysfunction. The most frequent cause of low-gradient (LG) AS is the presence of a low LV outflow state, which may occur with reduced left ventricular ejection fraction (LVEF), i.e. classical low-flow, low-gradient (LF-LG), or preserved LVEF, i.e. paradoxical LF-LG. Furthermore, a substantial proportion of patients with AS may have a normal-flow, low-gradient (NF-LG) AS: i.e. a small AVA-low-gradient combination but with a normal flow. One of the most important clinical challenges in these three categories of patients with LG AS (classical LF-LG, paradoxical LF-LG, and NF-LG) is to differentiate a true-severe AS that generally benefits from AVR vs. a pseudo-severe AS that should be managed conservatively. A low-dose dobutamine stress echocardiography may be used for this purpose in patients with classical LF-LG AS, whereas aortic valve calcium scoring by multi-detector computed tomography is the preferred modality in those with paradoxical LF-LG or NF-LG AS. Although patients with LF-LG severe AS have worse outcomes than those with high-gradient AS following AVR, they nonetheless display an important survival benefit with this intervention. Some studies suggest that transcatheter AVR may be superior to surgical AVR in patients with LF-LG AS. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  5. Graded/Gradient Porous Biomaterials

    Directory of Open Access Journals (Sweden)

    Xigeng Miao

    2009-12-01

    Full Text Available Biomaterials include bioceramics, biometals, biopolymers and biocomposites and they play important roles in the replacement and regeneration of human tissues. However, dense bioceramics and dense biometals pose the problem of stress shielding due to their high Young’s moduli compared to those of bones. On the other hand, porous biomaterials exhibit the potential of bone ingrowth, which will depend on porous parameters such as pore size, pore interconnectivity, and porosity. Unfortunately, a highly porous biomaterial results in poor mechanical properties. To optimise the mechanical and the biological properties, porous biomaterials with graded/gradient porosity, pores size, and/or composition have been developed. Graded/gradient porous biomaterials have many advantages over graded/gradient dense biomaterials and uniform or homogenous porous biomaterials. The internal pore surfaces of graded/gradient porous biomaterials can be modified with organic, inorganic, or biological coatings and the internal pores themselves can also be filled with biocompatible and biodegradable materials or living cells. However, graded/gradient porous biomaterials are generally more difficult to fabricate than uniform or homogenous porous biomaterials. With the development of cost-effective processing techniques, graded/gradient porous biomaterials can find wide applications in bone defect filling, implant fixation, bone replacement, drug delivery, and tissue engineering.

  6. Dose gradient curve: A new tool for evaluating dose gradient.

    Science.gov (United States)

    Sung, KiHoon; Choi, Young Eun

    2018-01-01

    Stereotactic radiotherapy, which delivers an ablative high radiation dose to a target volume for maximum local tumor control, requires a rapid dose fall-off outside the target volume to prevent extensive damage to nearby normal tissue. Currently, there is no tool to comprehensively evaluate the dose gradient near the target volume. We propose the dose gradient curve (DGC) as a new tool to evaluate the quality of a treatment plan with respect to the dose fall-off characteristics. The average distance between two isodose surfaces was represented by the dose gradient index (DGI) estimated by a simple equation using the volume and surface area of isodose levels. The surface area was calculated by mesh generation and surface triangulation. The DGC was defined as a plot of the DGI of each dose interval as a function of the dose. Two types of DGCs, differential and cumulative, were generated. The performance of the DGC was evaluated using stereotactic radiosurgery plans for virtual targets. Over the range of dose distributions, the dose gradient of each dose interval was well-characterized by the DGC in an easily understandable graph format. Significant changes in the DGC were observed reflecting the differences in planning situations and various prescription doses. The DGC is a rational method for visualizing the dose gradient as the average distance between two isodose surfaces; the shorter the distance, the steeper the dose gradient. By combining the DGC with the dose-volume histogram (DVH) in a single plot, the DGC can be utilized to evaluate not only the dose gradient but also the target coverage in routine clinical practice.

  7. Theory of neoclassical ion temperature-gradient-driven turbulence

    Science.gov (United States)

    Kim, Y. B.; Diamond, P. H.; Biglari, H.; Callen, J. D.

    1991-02-01

    The theory of collisionless fluid ion temperature-gradient-driven turbulence is extended to the collisional banana-plateau regime. Neoclassical ion fluid evolution equations are developed and utilized to investigate linear and nonlinear dynamics of negative compressibility ηi modes (ηi≡d ln Ti/d ln ni). In the low-frequency limit (ωB2p. As a result of these modifications, growth rates are dissipative, rather than sonic, and radial mode widths are broadened [i.e., γ˜k2∥c2s(ηi -(2)/(3) )/μi, Δx˜ρs(Bt/Bp) (1+ηi)1/2, where k∥, cs, and ρs are the parallel wave number, sound velocity, and ion gyroradius, respectively]. In the limit of weak viscous damping, enhanced neoclassical polarization persists and broadens radial mode widths. Linear mixing length estimates and renormalized turbulence theory are used to determine the ion thermal diffusivity in both cases. In both cases, a strong favorable dependence of ion thermal diffusivity on Bp (and hence plasma current) is exhibited. Furthermore, the ion thermal diffusivity for long wavelength modes exhibits favorable density scaling. The possible role of neoclassical ion temperature-gradient-driven modes in edge fluctuations and transport in L-phase discharges and the L to H transition is discussed.

  8. Electromagnetic Wave Chaos in Gradient Refractive Index Optical Cavities

    International Nuclear Information System (INIS)

    Wilkinson, P. B.; Fromhold, T. M.; Taylor, R. P.; Micolich, A. P.

    2001-01-01

    Electromagnetic wave chaos is investigated using two-dimensional optical cavities formed in a cylindrical gradient refractive index lens with reflective surfaces. When the planar ends of the lens are cut at an angle to its axis, the geometrical ray paths are chaotic. In this regime, the electromagnetic mode spectrum of the cavity is modulated by both real and ghost periodic ray paths, which also 'scar' the electric field intensity distributions of many modes. When the cavity is coupled to waveguides, the eigenmodes generate complex series of resonant peaks in the electromagnetic transmission spectrum

  9. Meta-Analysis of Randomized Clinical Trials Comparing Biodegradable Polymer Drug-Eluting Stent to Second-Generation Durable Polymer Drug-Eluting Stents.

    Science.gov (United States)

    El-Hayek, Georges; Bangalore, Sripal; Casso Dominguez, Abel; Devireddy, Chandan; Jaber, Wissam; Kumar, Gautam; Mavromatis, Kreton; Tamis-Holland, Jacqueline; Samady, Habib

    2017-03-13

    The authors sought to perform a meta-analysis of randomized clinical trials (RCTs) comparing the safety and efficacy of biodegradable polymer drug-eluting stents (BP-DES) to second-generation durable polymer drug-eluting stents (DP-DES). Prior meta-analyses have established the superiority of BP-DES over bare-metal stents and first-generation DP-DES; however, their advantage compared with second-generation DP-DES remains controversial. The authors searched PubMed and Scopus databases for RCTs comparing BP-DES to the second-generation DP-DES. Outcomes included target vessel revascularization (TVR) as efficacy outcome and cardiac death, myocardial infarction (MI), and definite or probable stent thrombosis (ST) as safety outcomes. In addition, we performed landmark analysis for endpoints beyond 1 year of follow-up and a subgroup analysis based on the stent characteristics. The authors included 16 RCTs comprising 19,886 patients in the meta-analysis. At the longest available follow-up (mean duration 26 months), we observed no significant differences in TVR (p = 0.62), cardiac death (p = 0.46), MI (p = 0.98), or ST (risk ratio: 0.83, 95% confidence interval: 0.64 to 1.09; p = 0.19). Our landmark analysis showed that BP-DES were not associated with a reduction in the risk of very late ST (risk ratio: 0.87, 95% confidence interval: 0.49 to 1.53; p = 0.62). Similar outcomes were seen regardless of the eluting drug (biolimus vs. sirolimus), the stent platform (stainless steel vs. alloy), the kinetics of polymer degradation or drug release (6 months), the strut thickness of the BP-DES (thin 100 μm), or the DAPT duration (≥6 months vs. ≥12 months). BP-DES have similar safety and efficacy profiles to second-generation DP-DES. Published by Elsevier Inc.

  10. Separation and determination of polyurethane amine catalysts in polyether polyols by using UHPLC-Q-TOF-MS on a reversed-phase/cation-exchange mixed-mode column.

    Science.gov (United States)

    Li, Jiaxiao; Zhu, Marcel

    2018-02-01

    A simple, selective, and accurate ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method was established and validated for the efficient separation and quantification of polyurethane amine catalysts in polyether polyols. Amine catalysts were primarily separated in polyether polyol-based sample by solid-phase extraction, and further baseline separated on a reversed-phase/cation-exchange mixed-mode column (SiELC Primesep™ 200) using 0.1% trifluoroacetic acid/acetonitrile as a mobile phase in gradient elution mode at a flow rate of 0.2 mL/min. High-resolution quadrupole time-of-flight mass spectrometry analysis in electrospray ionization positive mode allowed the identification as N,N'-bis[3-(dimethylamino)propyl]urea, N-[2-(2-dimethylaminoethoxy)ethyl]-N-methyl-1,3-propanediamine, and N,N,N',N'-tetramethyldipropylenetriamine. The method was validated and presented good linearity for all the analytes in blank matrices within the concentration range of 0.20-5.0 or 0.1-2.0 μg/mL with the correlation coefficients (R 2 ) ranging from 0.986 to 0.997. Method recovery ranged within 81-105% at all three levels (80, 100, and 120% of the original amount) with relative standard deviations of 1.0-6.2%. The limits of detection were in the range of 0.007-0.051 μg/mL. Good precision was obtained with relative standard deviation below 3.2 and 0.72% for peak area and retention time of three amines, respectively. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Drug-eluting stents for acute coronary syndrome: a meta-analysis of randomized controlled trials.

    Directory of Open Access Journals (Sweden)

    Lishan Wang

    Full Text Available Drug-eluting stents (DES are increasingly used for treatment of acute coronary syndrome (ACS. However, clinical efficacy and safety of various types of DES is not well established in these subjects. We therefore evaluated clinical utility of second-generation and first-generation DES in patients with ACS by conducting a meta-analysis.A search of Medline, Embase, the Cochrane databases, and Web of Science was made. Randomized controlled trials (RCTs which compared second-generation DES (everolimus-eluting stents [EES] or zotarolimus-eluting stents [ZES] versus first-generation DES (sirolimus-eluting stents [SES] or paclitaxe-eluting stents [PES] in patients with ACS and provided data on clinical efficacy or safety endpoints were included. Pooled estimates were calculated using random-effects model.A total of 2,757 participants with ACS in 6 RCTs were included. Compared with first-generation one, second-generation DES trended to be associated with the decreased incidence of definite or probable stent thrombosis in ACS patients (risk ratio [RR]  = 0.60, 95% confidence intervals [CI] 0.33 to 1.07, p = 0.09. However, the rate of target lesion revascularization (TLR significantly increased in second-generation DES (RR = 2.08, 95%CI 1.25 to 3.47, p = 0.005. There were no significant differences in the incidence of major adverse cardiac events (MACEs, all-cause death, cardiac death, and recurrent myocardial infarction between the two arms (all p>0.10. The second-generation EES showed a tendency towards lower risk of MACEs (p = 0.06 and a beneficial effect on reducing stent thrombosis episodes (p = 0.009, while the second-generation ZES presented an increased occurrence of MACEs (p = 0.02 and TLR (p = 0.003.Second-generation DES, especially EES, appeared to present a lower risk of stent thrombosis, whereas second-generation ZES might increase the need for repeat revascularization in ACS patients. During coronary

  12. Biodegradable Polymer Biolimus-Eluting Stents Versus Durable Polymer Everolimus-Eluting Stents in Patients With Coronary Artery Disease: Final 5-Year Report From the COMPARE II Trial (Abluminal Biodegradable Polymer Biolimus-Eluting Stent Versus Durable Polymer Everolimus-Eluting Stent).

    Science.gov (United States)

    Vlachojannis, Georgios J; Smits, Pieter C; Hofma, Sjoerd H; Togni, Mario; Vázquez, Nicolás; Valdés, Mariano; Voudris, Vassilis; Slagboom, Ton; Goy, Jean-Jaques; den Heijer, Peter; van der Ent, Martin

    2017-06-26

    This analysis investigates the 5-year outcomes of the biodegradable polymer biolimus-eluting stent (BP-BES) and durable polymer everolimus-eluting stent (DP-EES) in an all-comers population undergoing percutaneous coronary intervention. Recent 1- and 3-year results from randomized trials have indicated similar safety and efficacy outcomes of BP-BES and DP-EES. Whether benefits of the biodegradable polymer device arise over longer follow-up is unknown. Moreover, in-depth, prospective, long-term follow-up data on metallic drug-eluting stents with durable or biodegradable polymers are scarce. The COMPARE II trial (Abluminal Biodegradable Polymer Biolimus-Eluting Stent Versus Durable Polymer Everolimus-Eluting Stent) was a prospective, randomized, multicenter, all-comers trial in which 2,707 patients were randomly allocated (2:1) to BP-BES or DP-EES. The pre-specified endpoint at 5 years was major adverse cardiac events, a composite of cardiac death, nonfatal myocardial infarction, or target vessel revascularization. Five-year follow-up was available in 2,657 patients (98%). At 5 years, major adverse cardiac events occurred in 310 patients (17.3%) in the BP-BES group and 142 patients (15.6%) in the DP-EES group (p = 0.26). The rate of the combined safety endpoint all-cause death or myocardial infarction was 15.0% in the BP-BES group versus 14.8% in the DP-EES group (p = 0.90), whereas the efficacy measure target vessel revascularization was 10.6% versus 9.0% (p = 0.18), respectively. Interestingly, definite stent thrombosis rates did not differ between groups (1.5% for BP-BES vs. 0.9% for DP-EES; p = 0.17). The 5-year analysis comparing biodegradable polymer-coated BES and the durable polymer-coated EES confirms the initial early- and mid-term results regarding similar safety and efficacy outcomes in this all-comers percutaneous coronary intervention population. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights

  13. Effect of Opalescence® bleaching gels on the elution of dental composite components.

    Science.gov (United States)

    Schuster, Lena; Rothmund, Lena; He, Xiuli; Van Landuyt, Kirsten L; Schweikl, Helmut; Hellwig, Elmar; Carell, Thomas; Hickel, Reinhard; Reichl, Franz-Xaver; Högg, Christof

    2015-06-01

    Bleaching treatments can affect on the polymer network of dental composites. This study was performed to evaluate the influence of different bleaching treatments on the elution of composite components. The composites Tetric EvoCeram(®), CLEARFIL™ AP-X, Tetric EvoFlow(®), Filtek™ Supreme XT, Ceram X(®) mono+, Admira and Filtek™ Silorane were treated with the bleaching gels Opalescence PF 15% (PF 15%) for 5h and PF 35% (PF 35%) for 30 min and then stored in methanol and water for 24h and 7 d. The eluates were analyzed by gas chromatography/mass spectrometry (GC/MS). Unbleached specimens were used as control group. A total of 16 different elutable substances have been identified from the investigated composites after bleaching-treatment. Six of them were methacrylates: 1,10-decandioldimethacrylate (DDDMA), 1,12-dodekandioldimethacrylate (DODDMA), ethylenglycoldimethacrylate (EGDMA), 2-hydroxyethylmethacrylate (HEMA), triethylenglycoldimethacrylate (TEGDMA) and urethandimethacrylate (UDMA). Compared with the unbleached controls the composites Tetric EvoCeram(®), CLEARFIL™ AP-X and Tetric EvoFlow(®) showed a reduced elution of UDMA, TEGDMA and HEMA after bleaching-treatment. Compared with the unbleached controls an increase elution of UDMA, DMABEE, BPA and TEGDMA for the composites Filtek™ Supreme XT, Ceram X(®) mono+, Admira and Filtek™ Silorane after bleaching-treatment has been detected. The highest concentration of UDMA was 0.01 mmol/l (Tetric EvoCeram(®), water, 24h, controls), the highest concentration of TEGDMA was 0.28 mmol/l (CLEARFIL™ AP-X, water, 7 d, controls), the highest concentration of HEMA was 0.74 mmol/l (Tetric EvoFlow(®), methanol, 7 d, PF 35%), the highest concentration of DMABEE was 0.10 mmol/l (Ceram X(®) mono+, water, 7 d, PF 35%) and the highest concentration of BPA was 0.01 mmol/l (Admira, methanol, 7 d, controls). Bleaching treatments can lead to a reduced or an increased elution of substances from the dental composites

  14. Influence of amount of oxidizing slag discharged from stainless steelmaking process of electric arc furnace on elution behavior into fresh water

    International Nuclear Information System (INIS)

    Yokoyama, S; Izaki, M; Shimomura, T; Hisyamudin, M N N; Takahashi, T

    2012-01-01

    Fundamental study was carried out for provision for acidification of soil due to acid rain. The influence of weight of the additive slag on elution behavior of the slag into water was studied in this study. Elution experiment was carried out on a basis of JIS K 0058-1. Generally, the pH in the aqueous solution increased with an increase in weight of the additive slag. The pH converged to approximately eight. Calcium, magnesium and manganese, which were essential elements for plants, were eluted from the slag irrespective to elution condition. The eluted concentrations of Ca and Mg increased with an increase in weight of the additive slag. Silicon and zinc were also eluted depending on the conditions. Aluminum that was harmful for plants was not eluted from the used slag.

  15. Influence of amount of oxidizing slag discharged from stainless steelmaking process of electric arc furnace on elution behavior into fresh water

    Science.gov (United States)

    Yokoyama, S.; Shimomura, T.; Hisyamudin, M. N. N.; Takahashi, T.; Izaki, M.

    2012-03-01

    Fundamental study was carried out for provision for acidification of soil due to acid rain. The influence of weight of the additive slag on elution behavior of the slag into water was studied in this study. Elution experiment was carried out on a basis of JIS K 0058-1. Generally, the pH in the aqueous solution increased with an increase in weight of the additive slag. The pH converged to approximately eight. Calcium, magnesium and manganese, which were essential elements for plants, were eluted from the slag irrespective to elution condition. The eluted concentrations of Ca and Mg increased with an increase in weight of the additive slag. Silicon and zinc were also eluted depending on the conditions. Aluminum that was harmful for plants was not eluted from the used slag.

  16. Behavior of phenolic substances in the decaying process of plants. V. Elution of heavy metals with phenolic acids from soil

    Energy Technology Data Exchange (ETDEWEB)

    Shindo, H; Kuwatsuka, S

    1977-01-01

    The relationship between the elution of heavy metals with phenolic substances and the chemical structure of phenolic substances, as well as the interaction between phenolic substances and metals were studied using batch and column methods. The elution of 3 metals (Fe, Al and Mn) with 4 phenolic acids (rho-hydroxybenzoic, salicylic, ..cap alpha..-resorcylic, and protocatechuic acids) and phthalic acid were investigated using 3 different soils. The results are as follows: (1) The elution of heavy metals was largely influenced by the chemical structures of the phenolic acids. Protocatechuic, salicylic, and phthalic acids which had different chelating sites easily extracted iron, aluminum, and manganese from the soils. Hydroxybenzoic and ..cap alpha..-resorcylic acids which had no chelating sites contributed little to the elution process. (2) In many cases protocatechuic acid showed a stronger affinity to iron than to aluminum, but salicylic acid showed the opposite trend. The affinity of phthalic acid to metals was much less than that of both phenolic acids. (3) The elution of heavy metals was also influenced by the soil pH. The amounts of heavy metals eluted with protocatechuic acid increased as the soil pH increased. The amounts eluted with salicylic and phthalic acids increased as the soil pH decreased. (4) The results suggested that chelating phenolics such as protocatechuic and salicylic acids, which were exuded from plant residues or produced during the decaying process of plant residues, eluted heavy metals such as iron, aluminum and manganese from soil particles and accelerated the downward movement of these metal ions.

  17. Clinical outcomes with drug-eluting and bare-metal stents in patients with ST-segment elevation myocardial infarction

    DEFF Research Database (Denmark)

    Palmerini, Tullio; Biondi-Zoccai, Giuseppe; Della Riva, Diego

    2013-01-01

    The authors investigated the relative safety and efficacy of different drug-eluting stents (DES) and bare metal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI) using a network meta-analysis.......The authors investigated the relative safety and efficacy of different drug-eluting stents (DES) and bare metal stents (BMS) in patients with ST-segment elevation myocardial infarction (STEMI) using a network meta-analysis....

  18. Outcome of Sirolimus-Eluting Versus Zotarolimus-Eluting Coronary Stent Implantation in Patients With and Without Diabetes Mellitus (a SORT OUT III Substudy)

    DEFF Research Database (Denmark)

    Maeng, Michael; Jensen, Lisette O; Tilsted, Hans-Henrik

    2011-01-01

    Diabetes is associated with an increased risk of major adverse cardiac events after percutaneous coronary intervention. We compared clinical outcomes in patients with and without diabetes mellitus treated with the second-generation Endeavor zotarolimus-eluting stent (ZES) or the first...... cardiac events defined as a composite of cardiac death, myocardial infarction, or target vessel revascularization. Secondary end points included these individual end points plus all-cause mortality and target lesion revascularization. In diabetic patients, use of ZES compared to SES was associated.......90 to 13.1), and target lesion revascularization (12.4% vs 1.2%, hazard ratio 11.0, 95% confidence interval 2.59 to 47.1). In patients without diabetes differences in absolute risk decrease were smaller but similarly favored SES. In conclusion, implantation of ZESs compared to SESs is associated...

  19. Everolimus-eluting bioresorbable stent vs. durable polymer everolimus-eluting metallic stent in patients with ST-segment elevation myocardial infarction

    DEFF Research Database (Denmark)

    Sabaté, Manel; Windecker, Stephan; Iñiguez, Andres

    2015-01-01

    AIMS: Patients with ST-segment elevation myocardial infarction (STEMI) feature thrombus-rich lesions with large necrotic core, which are usually associated with delayed arterial healing and impaired stent-related outcomes. The use of bioresorbable vascular scaffolds (Absorb) has the potential...... to overcome these limitations owing to restoration of native vessel lumen and physiology at long term. The purpose of this randomized trial was to compare the arterial healing response at short term, as a surrogate for safety and efficacy, between the Absorb and the metallic everolimus-eluting stent (EES...... was the 6-month optical frequency domain imaging healing score (HS) based on the presence of uncovered and/or malapposed stent struts and intraluminal filling defects. Main secondary endpoint included the device-oriented composite endpoint (DOCE) according to the Academic Research Consortium definition...

  20. Theory of neoclassical resistivity-gradient-driven turbulence

    International Nuclear Information System (INIS)

    Kwon, O.J.; Diamond, P.H.; Hahm, T.S.

    1988-12-01

    It is shown that rippling instabilities can tap the density gradient expansion free energy source through the density dependence of the neoclassical resistivity. Linear analyses show that the region where neoclassical rippling modes are significantly excited extends from the edge of the plasma to the region where ν/sub *e/ ≤ 1. Since these modes are non-dispersive, diamagnetic effects are negligible in comparison to the nonlinear decorrelation rate at saturation. Thus, the relevant regime is the 'strong turbulence' regime. The turbulent radial diffusivities of the temperature and the density are obtained as eigenvalues of the renormalized eigenmode equations at steady state. The density gradient acts to enhance the level of turbulence, compared to that driven by the temperature gradient alone. The saturated turbulent state is characterized by: current decoupling, the breakdown of Boltzmann relation, a radial mode scale of density fluctuations exceeding that of temperature fluctuations, implying that density diffusivity exceeds temperature diffusivity, and that density fluctuation levels exceed temperature fluctuation levels. Magnetic fluctuation levels are negligible. 29 refs., 1 fig

  1. Paclitaxel-eluting stents versus everolimus-eluting coronary stents in a diabetic population: two-year follow-up of the TUXEDO-India trial.

    Science.gov (United States)

    Kaul, Upendra; Bhagwat, Ajit; Pinto, Brian; Goel, Praveen K; Jagtap, Prashant; Sathe, Shireesh; Wander, Gurpreet S; Arambam, Priyadarshini; Bangalore, Sripal

    2017-11-20

    The aim of this study was to report whether the superiority of the everolimus-eluting stent (EES) vs. the paclitaxel-eluting stent (PES) at one-year follow-up in the Taxus Element versus Xience Prime in a Diabetic Population (TUXEDO)-India trial was sustained at longer-term follow-up. One thousand eight hundred and thirty (1,830) patients with diabetes mellitus and coronary artery disease were randomised to EES vs. PES. Follow-up data up to two years were available in 1,701 (92.9%) patients. The primary endpoint was target vessel failure (TVF), defined as the composite of cardiac death, target vessel myocardial infarction (TV-MI), or ischaemia-driven target vessel revascularisation (TVR). Treatment with EES had a lower two-year rate of TVF (4.3% vs. 6.6%, p=0.03). Of the secondary endpoints, EES significantly reduced any MI (1.6% vs. 3.5%, p=0.01), TV-MI (0.7% vs. 3.1%, p=0.0001), ST (0.4% vs. 2.2%, p=0.001), cardiac death or target vessel MI (2.9% vs. 4.8%, p=0.04) and TLR (1.9% vs. 3.7%, p=0.02), compared with PES. Between one year and two years, no significant differences in the clinical outcomes were observed (pinteraction >0.05). In this adequately powered trial, the benefits of EES vs. PES in a diabetic population seen at one year were maintained at two years.

  2. The role of drug-eluting balloons alone or in combination with drug-eluting stents in the treatment of de novo diffuse coronary disease.

    Science.gov (United States)

    Costopoulos, Charis; Latib, Azeem; Naganuma, Toru; Sticchi, Alessandro; Figini, Filippo; Basavarajaiah, Sandeep; Carlino, Mauro; Chieffo, Alaide; Montorfano, Matteo; Naim, Charbel; Kawaguchi, Masanori; Giannini, Francesco; Colombo, Antonio

    2013-11-01

    This study sought to investigate the role of drug-eluting balloons (DEB) alone or in combination with drug-eluting stents (DES) in the treatment of diffuse de novo coronary artery disease (CAD) (>25 mm). The use of DEB in diffuse CAD, either alone or in combination with DES, offers an alternative to stenting alone. Data regarding DEB in this context are limited. We retrospectively evaluated all patients treated with DEB for diffuse CAD between June 2009 and October 2012. Endpoints analyzed were major adverse cardiac events, defined as all-cause death, myocardial infarction, and target vessel revascularization (TVR), as well as TVR and target lesion revascularization separately. Results were compared with those obtained from a cohort of patients with similar characteristics treated with DES alone. A total of 69 patients (93 lesions) were treated with DEB ± DES, and 93 patients with DES alone (93 lesions). A high proportion of patients were diabetic (46.4% vs. 44.1%, p = 0.77). Of the DEB-treated lesions, 56.0% were treated with DEB alone, 7.4% with DEB and DES as bail out, and 36.6% with DES and DEB as part of a hybrid approach for very long disease. Outcome rates with DEB ± DES were comparable to those with DES alone at 2-year follow-up (major adverse cardiac events = 20.8% vs. 22.7%, p = 0.74; TVR = 14.8% vs. 11.5%, p = 0.44; target lesion revascularization = 9.6% vs. 9.3%, p = 0.84). DEB may have a role in the treatment of diffuse de novo CAD, either alone in smaller vessels or in combination with DES in very long disease. Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  3. Comparison of clinical outcomes after drug-eluting balloon and drug-eluting stent use for in-stent restenosis related acute myocardial infarction: a retrospective study

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Fang

    2018-04-01

    Full Text Available Background Good results of drug-eluting balloon (DEB use are achieved in in-stent restenosis (ISR lesions, small vessel disease, long lesions, and bifurcations. However, few reports exist about DEB use in acute myocardial infarction (AMI with ISR. This study’s aim was to evaluate the efficacy of DEB for AMI with ISR. Methods Between November 2011 and December 2015, 117 consecutive patients experienced AMI including ST-segment elevation MI, and non-ST-segment elevation MI due to ISR, and received percutaneous coronary intervention (PCI. We divided our patients into two groups: (1 PCI with further DEB, and (2 PCI with further drug-eluting stent (DES. Clinical outcomes such as target lesion revascularization, target vessel revascularization, recurrent MI, stroke, cardiovascular mortality, and all-cause mortality were analyzed. Results The patients’ average age was 68.37 ± 11.41 years; 69.2% were male. A total of 75 patients were enrolled in the DEB group, and 42 patients were enrolled in the DES group. The baseline characteristics between the two groups were the same without statistical differences except for gender. Peak levels of cardiac biomarker, pre- and post-PCI cardiac function were similar between two groups. The major adverse cardiac cerebral events rate (34.0% vs. 35.7%; p = 0.688 and cardiovascular mortality rate (11.7% vs. 12.8%; p = 1.000 were similar in both groups. Conclusions DEB is a reasonable strategy for AMI with ISR. Compared with DES, DEB is an alternative strategy which yielded acceptable short-term outcomes and similar 1-year clinical outcomes.

  4. Toxic vessel reaction to an absorbable polymer-based paclitaxel-eluting stent in pig coronary arteries.

    Science.gov (United States)

    Jabara, Refat; Chronos, Nicolas; Tondato, Fernando; Conway, Damian; Molema, Warner; Park, Kenneth; Mabin, Tom; King, Spencer; Robinson, Keith

    2006-08-01

    The goal of this study was to evaluate a new drug-eluting stent (DES) comprising a bioabsorbable polymer eluting a moderate dose of paclitaxel in a clinically relevant animal model. Although DES limit restenosis, adverse vascular pathologies and toxicities continue to be of major concern. Optimization of DES components, especially completely absorbable polymers, may reduce these toxicities. Bare-metal (BM), absorbable polymer coating only (POLY), and polymer-based paclitaxel-eluting (PACL) stents were implanted in porcine coronary arteries using intravascular ultrasound (IVUS) to optimize stent apposition. The dose density of paclitaxel was 0.30-0.35 mcg/mm2, with in vitro elution studies demonstrating a gradual elution over 6-8 weeks. The animals were terminated at 1 week, 1 month and 3 months. Histopathologic and histomorphometric analyses were perform. The arteries with PACL showed extensive smooth muscle cell necrosis at 1 week and poor apposition of stent struts at 1 month (malapposition measured as gap width between strut and internal elastic lamina), with greater gap width compared to the BM and POLY groups (0.22 mm +/- 0.02 vs. 0.03 mm +/- 0.02 and 0.02 mm +/- 0.01, respectively; p stent malapposition and late neointimal thickening. Since the therapeutic window for paclitaxel may be narrower than currently inferred, thorough preclinical testing coupled with the polymer development process for stents eluting paclitaxel is needed.

  5. A case of Z/E-isomers elution order inversion caused by cosolvent percentage change in supercritical fluid chromatography.

    Science.gov (United States)

    Pokrovskiy, Oleg I; Ustinovich, Konstantin B; Usovich, Oleg I; Parenago, Olga O; Lunin, Valeriy V; Ovchinnikov, Denis V; Kosyakov, Dmitry S

    2017-01-06

    A case of elution order inversion caused by cosolvent percentage change in supercritical fluid chromatography was observed and investigated in some detail. Z- and E-isomers of phenylisobutylketone oxime experience an elution order reversal on most columns if the mobile phase consists of CO 2 and alcohol. At lower percentages of alcohol Z-oxime is retained less, somewhere at 2-5% coelution occurs and at larger cosolvent volume elution order reverses - Z-oxime is eluted later than E-oxime. We suppose inversion with CO 2 -ROH phases happens due to a shift in balance between two main interactions governing retention. At low ROH percentages stationary phase surface is only slightly covered by ROH molecules so oximes primarily interact with adsorption sites via hydrogen bond formation. Due to intramolecular sterical hindrance Z-oxime is less able to form hydrogen bonds and consequently is eluted first. At higher percentages alcohols occupy most of strong hydrogen bonding sites on silica surface thus leaving non-specific electrostatic interactions predominantly responsible for Z/E selectivity. Z-oxime has a much larger dipole moment than E-oxime and at these conditions it is eluted later. Additional experimental data with CO 2 -CH 3 CN, hexane-iPrOH and CHF 3 -ROH mobile phases supporting this explanation are presented. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Near field plasmonic gradient effects on high vacuum tip-enhanced Raman spectroscopy.

    Science.gov (United States)

    Fang, Yurui; Zhang, Zhenglong; Chen, Li; Sun, Mengtao

    2015-01-14

    Near field gradient effects in high vacuum tip-enhanced Raman spectroscopy (HV-TERS) are a recent developing ultra-sensitive optical and spectral analysis technology on the nanoscale, based on the plasmons and plasmonic gradient enhancement in the near field and under high vacuum. HV-TERS can not only be used to detect ultra-sensitive Raman spectra enhanced by surface plasmon, but also to detect clear molecular IR-active modes enhanced by strongly plasmonic gradient. Furthermore, the molecular overtone modes and combinational modes can also be experimentally measured, where the Fermi resonance and Darling-Dennison resonance were successfully observed in HV-TERS. Theoretical calculations using electromagnetic field theory firmly supported experimental observation. The intensity ratio of the plasmon gradient term over the linear plasmon term can reach values greater than 1. Theoretical calculations also revealed that with the increase in gap distance between tip and substrate, the decrease in the plasmon gradient was more significant than the decrease in plasmon intensity, which is the reason that the gradient Raman can be only observed in the near field. Recent experimental results of near field gradient effects on HV-TERS were summarized, following the section of the theoretical analysis.

  7. Rapid Gradient-Echo Imaging

    Science.gov (United States)

    Hargreaves, Brian

    2012-01-01

    Gradient echo sequences are widely used in magnetic resonance imaging (MRI) for numerous applications ranging from angiography to perfusion to functional MRI. Compared with spin-echo techniques, the very short repetition times of gradient-echo methods enable very rapid 2D and 3D imaging, but also lead to complicated “steady states.” Signal and contrast behavior can be described graphically and mathematically, and depends strongly on the type of spoiling: fully balanced (no spoiling), gradient spoiling, or RF-spoiling. These spoiling options trade off between high signal and pure T1 contrast while the flip angle also affects image contrast in all cases, both of which can be demonstrated theoretically and in image examples. As with spin-echo sequences, magnetization preparation can be added to gradient-echo sequences to alter image contrast. Gradient echo sequences are widely used for numerous applications such as 3D perfusion imaging, functional MRI, cardiac imaging and MR angiography. PMID:23097185

  8. The influence of ALN-Al gradient material gradient index on ballistic performance

    International Nuclear Information System (INIS)

    Wang Youcong; Liu Qiwen; Li Yao; Shen Qiang

    2013-01-01

    Ballistic performance of the gradient material is superior to laminated material, and gradient materials have different gradient types. Using ls-dyna to simulate the ballistic performance of ALN-AL gradient target plates which contain three gradient index (b = 1, b = 0.5, b = 2). Through Hopkinson bar numerical simulation to the target plate materials, we obtained the reflection stress wave and transmission stress wave state of gradient material to get the best gradient index. The internal stress state of gradient material is simulated by amplification processing of the target plate model. When the gradient index b is equal to 1, the gradient target plate is best of all.

  9. Stent Thrombosis With Drug-Eluting Stents and Bioresorbable Scaffolds: Evidence From a Network Meta-Analysis of 147 Trials.

    Science.gov (United States)

    Kang, Si-Hyuck; Chae, In-Ho; Park, Jin-Joo; Lee, Hak Seung; Kang, Do-Yoon; Hwang, Seung-Sik; Youn, Tae-Jin; Kim, Hyo-Soo

    2016-06-27

    This study sought to perform a systematic review and network meta-analysis to compare the relative safety and efficacy of contemporary DES and BVS. To improve outcomes of patients undergoing percutaneous coronary revascularization, there have been advances in the design of drug-eluting stents (DES), including the development of drug-eluting bioresorbable vascular scaffolds (BVS). Prospective, randomized, controlled trials comparing bare-metal stents (BMS), paclitaxel-eluting stents (PES), sirolimus-eluting stents (SES), Endeavor zotarolimus-eluting stents (E-ZES), cobalt-chromium (CoCr) everolimus-eluting stents (EES), platinum-chromium (PtCr)-EES, biodegradable polymer (BP)-EES, Resolute zotarolimus-eluting stents (R-ZES), BP biolimus-eluting stents (BP-BES), hybrid sirolimus-eluting stents (H [Orsiro]-SES), polymer-free sirolimus- and probucol-eluting stents, or BVS were searched in online databases. The primary endpoint was definite or probable stent thrombosis at 1 year. A total of 147 trials including 126,526 patients were analyzed in this study. All contemporary DES were superior to BMS and PES in terms of definite or probable stent thrombosis at 1 year. CoCr-EES, PtCr-EES, and H-SES were associated with significantly lower risk than BVS. CoCr-EES and H-SES were superior to SES and BP-BES. The risk of myocardial infarction was significantly lower with H-SES than with BVS. There were no significant differences regarding all-cause or cardiac mortality. Contemporary devices including BVS showed comparably low risks of repeat revascularization. Contemporary DES, including biocompatible DP-DES, BP-DES, and polymer-free DES, showed a low risk of definite or probable stent thrombosis at 1 year. BVS had an increased risk of device thrombosis compared with CoCr-EES, PtCr-EES, and H-SES. Data from extended follow-up are warranted to confirm the long-term safety of contemporary coronary devices. Copyright © 2016 American College of Cardiology Foundation. Published by

  10. Modification of H-Mode Pedestal Instabilities in the DIII-D Tokamak

    International Nuclear Information System (INIS)

    J.R. Ferron; M.S. Chu; G.L. Jackson; L.L. Lao; R.L. Miller; T.H. Osborne; P.B. Snyder; E.J. Strait; T.S. Taylor; A.D. Turnbull; A.M. Garofalo; M.A. Makowski; B.W. Rice; M.S. Chance; L.R. Baylor; M. Murakami; M.R. Wade

    1999-01-01

    Through comparison of experiment and ideal magnetohydrodynamic (MHD) theory, modes driven in the edge region of tokamak H-mode discharges [Type I edge-localized modes (ELMs)] are shown to result from low toroidal mode number (n) instabilities driven by pressure gradient and current density. The mode amplitude and frequency are functions of the discharge shape. Reductions in mode amplitude are observed in discharge shapes with either high squareness or low triangularity where the low-n stability threshold in the edge pressure gradient is predicted to be reduced and the most unstable mode is expected to have higher values of n. The importance of access to the ballooning mode second stability regime is demonstrated through the changes in the ELM character that occur when second regime access is not available. An edge stability model is presented that predicts that there is a threshold value of n for second regime access and that the most unstable mode has n near this threshold

  11. Country report: Vietnam. Setting Up of a 90Sr/90Y Generator System Based on Supported Liquid Membrane (SLM) Technique and Radiolabeling of Eluted 90Y with Biomolecules

    International Nuclear Information System (INIS)

    Nguyen Thi Thu; Duong Van Dong; Bui Van Cuong; Chu Van Khoa

    2010-01-01

    In the course of participating in the IAEA-CRP during the last two years, Vietnam has achieved the goal of setting up a 90 Sr/ 90 Y generator system based on Supported Liquid Membrane (SLM) technique and also radiolabeling of the eluted 90 Y with antibody, peptides and albumin. A two stage SLM based 90 Sr- 90 Y generator was set up in-house to generate carrier-free 90 Y at different activity levels viz. 5, 20, 50 mCi. The generator system was operated in sequential mode in which 2-ethylhexyl 2-ethylhexyl phosphonic acid (PC88A) based SLM was used in the first stage for the transport 90 Y in 4.0 M nitric acid from source phase where 90 Sr- 90 Y equilibrium mixture is placed in nitric acid medium at pH to 1-2. In the second stage, octyl (phenyl)-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) based SLM was used for the transport of 90 Y selectively to 1.0 M acetic acid which is the best medium for radiolebeling. The eluted 90 Y from the generator was tested for the presence of any traces of 90 Sr using the Extraction Paper Chromatography (EPC) and was found suitable for radiolabeling. The generator system could be upgraded to 100 mCi level successfully due to an expert mission from India through IAEA. The 90 Y product obtained from the generator system was used for radiolabeling of antibody and peptides viz. Rituximab, DOTATATE and albumin particles under different experimental conditions. A new chromatography system could be developed for analyzing 90 Y labeled albumin using the TAE buffer as mobile phase in PC and ITLC

  12. Monitoring gradient profile on-line in micro- and nano-high performance liquid chromatography using conductivity detection.

    Science.gov (United States)

    Zhang, Min; Chen, Apeng; Lu, Joann J; Cao, Chengxi; Liu, Shaorong

    2016-08-19

    In micro- or nano-flow high performance liquid chromatography (HPLC), flow-splitters and gradient elutions are commonly used for reverse phase HPLC separations. When a flow splitter was used at a high split-ratio (e.g., 1000:1 or higher), the actual gradient may deviate away from the programmed gradient. Sometimes, mobile phase concentrations can deviate by as much as 5%. In this work, we noticed that the conductivity (σ) of a gradient decreased with the increasing organic-solvent fraction (φ). Based on the relationship between σ and φ, a method was developed for monitoring gradient profile on-line to record any deviations in these HPLC systems. The conductivity could be measured by a traditional conductivity detector or a capacitively coupled contactless conductivity detector (C(4)D). The method was applied for assessing the performance of an electroosmotic pump (EOP) based nano-HPLC. We also observed that σ value of the gradient changed with system pressure; a=0.0175ΔP (R(2)=0.964), where a is the percentage of the conductivity increase and ΔP is the system pressure in bar. This effect was also investigated. Copyright © 2016. Published by Elsevier B.V.

  13. Neoclassical tearing modes in a tokamak

    International Nuclear Information System (INIS)

    Hahm, T.S.

    1988-08-01

    Linear tearing instability is studied in the banana collisionality regime in tokamak geometry. Neoclassical effects produce significant modifications of Ohm's law and the vorticity equation so that the growth rate of tearing modes driven by Δ' is dramatically reduced compared to the usual resistive MHD value. Consequences of this result, regarding the presence of pressure-gradient-driven neoclassical resistive interchange instabilities and the evolution of magnetic islands in the Rutherford regime, are discussed. 10 refs

  14. Impact of ultrasonication time on elution of super heavy oil and its biomarkers from aging soils using a Triton X-100 micellar solution

    International Nuclear Information System (INIS)

    Ji Guodong; Zhou Guohui

    2010-01-01

    An ultrasound-enhanced elution system with Triton X-100 solution was used to remediate aging soils contaminated with super heavy oil. We used GC/MS, SEM, and X-ray diffraction (XRD) to analyze the effect of ultrasonic time (0-1800 s) on the elution of super heavy oil and its three characteristic biomarkers (C 26-34 17α 25-norhopanes, C 26-28 triaromatic steroid [TAS], and C 27-29 methyl triaromatic steroid [MTAS]). The oil and biomarkers remaining in the treated soils followed similar second-order functions with increasing ultrasonication times. Biomarker elution was closely related to carbon numbers in the marker. For C 26-34 17α 25-norhopanes, the smaller molecules were more readily eluted during 0-360 s ultrasound. This trend was reversed upon application of ultrasound during 1080-1800 s, with improved elution of larger molecules and elution followed a similar second-order function. For C 26-28 TAS, smaller molecules were more readily eluted but the elution of larger molecules followed a similar second-order function. For C 27-29 MTAS, elution of larger molecules was close to that of C 26-34 17α 25-norhopanes. Results of SEM and XRD indicated that the mineral and chemical compositions of soils eluted at ultrasonication times of 1080-1800 s closely resembled clean soils.

  15. Elution of Clindamycin and Enrofloxacin From Calcium Sulfate Hemihydrate Beads In Vitro.

    Science.gov (United States)

    Phillips, Heidi; Boothe, Dawn M; Bennett, R Avery

    2015-11-01

    To compare the in vitro elution characteristics of clindamycin and enrofloxacin from calcium sulfate hemihydrate beads containing a single antibiotic, both antibiotics, and each antibiotic incubated in the same eluent well. Experimental in vitro study. Calcium sulfate hemihydrate beads were formed by mixing with clindamycin and/or enrofloxacin to create 4 study groups: (1) 160 mg clindamycin/10 beads; (2) 160 mg enrofloxacin/10 beads; (3) 160 mg clindamycin + 160 mg enrofloxacin/10 beads; and (4) 160 mg clindamycin/5 beads and 160 mg enrofloxacin/5 beads. Chains of beads were formed in triplicate and placed in 5 mL phosphate buffered saline (PBS; pH 7.4 and room temperature) with constant agitation. Antibiotic-conditioned PBS was sampled at 14 time points from 1 hour to 30 days. Clindamycin and enrofloxacin concentrations in PBS were determined using high-performance liquid chromatography. Eluent concentrations from clindamycin-impregnated beads failed to remain sufficiently above minimum inhibitory concentration (MIC) for common infecting bacteria over the study period. Enrofloxacin eluent concentrations remained sufficiently above MIC for common wound pathogens of dogs and cats and demonstrated an atypical biphasic release pattern. No significant differences in elution occurred as a result of copolymerization of the antibiotics into a single bead or from individual beads co-eluting in the same eluent well. Clindamycin-impregnated beads cannot be recommended for treatment of infection at the studied doses; however, use of enrofloxacin-impregnated beads may be justified when susceptible bacteria are cultured. © Copyright 2015 by The American College of Veterinary Surgeons.

  16. Spectral Analysis Related to Bare-Metal and Drug-Eluting Coronary Stent Implantation

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rose Mary Ferreira Lisboa da, E-mail: roselisboa@cardiol.br [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil); Silva, Carlos Augusto Bueno [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil); Belo Horizonte, Hospital São João de Deus, Divinópolis, MG (Brazil); Greco, Otaviano José [Belo Horizonte, Hospital São João de Deus, Divinópolis, MG (Brazil); Moreira, Maria da Consolação Vieira [Faculdade de Medicina da UFMG, Divinópolis, MG (Brazil)

    2014-08-15

    The autonomic nervous system plays a central role in cardiovascular regulation; sympathetic activation occurs during myocardial ischemia. To assess the spectral analysis of heart rate variability during stent implantation, comparing the types of stent. This study assessed 61 patients (mean age, 64.0 years; 35 men) with ischemic heart disease and indication for stenting. Stent implantation was performed under Holter monitoring to record the spectral analysis of heart rate variability (Fourier transform), measuring the low-frequency (LF) and high-frequency (HF) components, and the LF/HF ratio before and during the procedure. Bare-metal stent was implanted in 34 patients, while the others received drug-eluting stents. The right coronary artery was approached in 21 patients, the left anterior descending, in 28, and the circumflex, in 9. As compared with the pre-stenting period, all patients showed an increase in LF and HF during stent implantation (658 versus 185 ms2, p = 0.00; 322 versus 121, p = 0.00, respectively), with no change in LF/HF. During stent implantation, LF was 864 ms2 in patients with bare-metal stents, and 398 ms2 in those with drug-eluting stents (p = 0.00). The spectral analysis of heart rate variability showed no association with diabetes mellitus, family history, clinical presentation, beta-blockers, age, and vessel or its segment. Stent implantation resulted in concomitant sympathetic and vagal activations. Diabetes mellitus, use of beta-blockers, and the vessel approached showed no influence on the spectral analysis of heart rate variability. Sympathetic activation was lower during the implantation of drug-eluting stents.

  17. Porous Polymer Drug-Eluting Coating Prepared by Radiation Induced Polymerization

    International Nuclear Information System (INIS)

    Veres, M.; Beiler, B.; Himics, L.; Tóth, S.; Koós, M.

    2010-01-01

    Many areas of modern medicine are almost unimaginable without the use of different kinds of implants. They used as replacements, supports, auxiliary devices etc. for various parts or functions of the body. Their use has many advantages, however there could be some drawbacks too, like the possibility of rejection, inflammation and other side-effects. Many of these drawbacks are directly related to the materials used for the implant fabrication. Coatings are widely used to eliminate the unwanted effects appearing after the implantation. In addition to the protection and separation of tissues from the implant material they could also enhance the functionality and the acceptance of the artificial device and also promote the regeneration of the tissues after the intervention. Drug-eluting coatings are a good example for the latter. By delivery and controlled elution of drugs they could actively suppress inflammatory reactions, allergy and rejection of the implant, and their activity is localized to the place where these effects could mainly occur – to the region of the implant. This project is aimed to develop a drug-eluting porous polymer coating by radiation induced polymerization that can be used in different medical implants. The primary objects for this research are coronary stents however these porous layers could have perspective in other types of medical devices too. The main objectives are to develop a method for coating the surface of medical grade metallic alloy wires, plates and tubes with a porous polymer nanocomposite layer prepared by radiation induced polymerization and to characterize the obtained coatings

  18. Antibiotic eluting clay mineral (Laponite®) for wound healing application: an in vitro study.

    Science.gov (United States)

    Ghadiri, M; Chrzanowski, W; Rohanizadeh, R

    2014-11-01

    Different materials in form of sponge, hydrogel and film have been developed and formulated for treating and dressing burn wounds. In this study, the potential of Laponite, a gel forming clay, in combination with an antimicrobial agent (mafenide), as a wound dressing material was tested in vitro. Laponite/mafenide (Lap/Maf) hydrogel was formulated in three different ratios of Lap/Maf 1:1, 1:2, 1:3. Laponite/mafenide/alginate (Lap/Maf/Alg) film was also formulated by combining Lap/Maf gel (1:1) with alginate. Intercalation rate of mafenide into the layers of Laponite nanoparticles and physico-chemical properties, including wound dressing characteristics of materials were studied using various analytical methods. Furthermore, the degradation of materials and the release profile of mafenide were investigated in simulated wound exudates fluid and antibacterial effectiveness of the eluted mafenide was tested on a range of bacterial species. The cytotoxicity of materials was also evaluated in skin fibroblast culture. The results showed that mafenide molecules were intercalated between the nano-sized layers of Laponite. The eluted mafenide showed active antibacterial effects against all three tested bacteria. All intercalated mafenide released from Lap/Maf 1:1 and 1:2 gel formulations and nearly 80% release from 1:3 formulation during test period. No significant difference was observed in release profile of mafenide between Lap/Maf/Alg film and Lap/Maf formulations. Wound dressing tests on Lap/Maf/Alg film showed it is a breathable dressing and has capacity to absorb wound exudates. The study showed that prepared Lap/Maf composite has the potential to be used as an antibiotic eluting gel or film for wound healing application. Additionally, Laponite has shown benefits in wound healing processes by releasing Mg(2+) ions and thereby reducing the cytotoxic effect of mafenide on fibroblast cells.

  19. Porous Polymer Drug-Eluting Coating Prepared by Radiation Induced Polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Veres, M.; Beiler, B.; Himics, L.; Tóth, S.; Koós, M., E-mail: vm@szfki.hu [Hungarian Academy of Sciences, Research Institute for Solid State Physics and Optics, Department of Laser Applications, Konkoly Thege Miklós ut 29-33, 1121 Budapest, P.O. Box 49, 1525 Budapest (Hungary)

    2010-07-01

    Many areas of modern medicine are almost unimaginable without the use of different kinds of implants. They used as replacements, supports, auxiliary devices etc. for various parts or functions of the body. Their use has many advantages, however there could be some drawbacks too, like the possibility of rejection, inflammation and other side-effects. Many of these drawbacks are directly related to the materials used for the implant fabrication. Coatings are widely used to eliminate the unwanted effects appearing after the implantation. In addition to the protection and separation of tissues from the implant material they could also enhance the functionality and the acceptance of the artificial device and also promote the regeneration of the tissues after the intervention. Drug-eluting coatings are a good example for the latter. By delivery and controlled elution of drugs they could actively suppress inflammatory reactions, allergy and rejection of the implant, and their activity is localized to the place where these effects could mainly occur – to the region of the implant. This project is aimed to develop a drug-eluting porous polymer coating by radiation induced polymerization that can be used in different medical implants. The primary objects for this research are coronary stents however these porous layers could have perspective in other types of medical devices too. The main objectives are to develop a method for coating the surface of medical grade metallic alloy wires, plates and tubes with a porous polymer nanocomposite layer prepared by radiation induced polymerization and to characterize the obtained coatings.

  20. Stents Eluting 6-Mercaptopurine Reduce Neointima Formation and Inflammation while Enhancing Strut Coverage in Rabbits.

    Directory of Open Access Journals (Sweden)

    Matthijs S Ruiter

    Full Text Available The introduction of drug-eluting stents (DES has dramatically reduced restenosis rates compared with bare metal stents, but in-stent thrombosis remains a safety concern, necessitating prolonged dual anti-platelet therapy. The drug 6-Mercaptopurine (6-MP has been shown to have beneficial effects in a cell-specific fashion on smooth muscle cells (SMC, endothelial cells and macrophages. We generated and analyzed a novel bioresorbable polymer coated DES, releasing 6-MP into the vessel wall, to reduce restenosis by inhibiting SMC proliferation and decreasing inflammation, without negatively affecting endothelialization of the stent surface.Stents spray-coated with a bioresorbable polymer containing 0, 30 or 300 μg 6-MP were implanted in the iliac arteries of 17 male New Zealand White rabbits. Animals were euthanized for stent harvest 1 week after implantation for evaluation of cellular stent coverage and after 4 weeks for morphometric analyses of the lesions.Four weeks after implantation, the high dose of 6-MP attenuated restenosis with 16% compared to controls. Reduced neointima formation could at least partly be explained by an almost 2-fold induction of the cell cycle inhibiting kinase p27Kip1. Additionally, inflammation score, the quantification of RAM11-positive cells in the vessel wall, was significantly reduced in the high dose group with 23% compared to the control group. Evaluation with scanning electron microscopy showed 6-MP did not inhibit strut coverage 1 week after implantation.We demonstrate that novel stents coated with a bioresorbable polymer coating eluting 6-MP inhibit restenosis and attenuate inflammation, while stimulating endothelial coverage. The 6-MP-eluting stents demonstrate that inhibition of restenosis without leaving uncovered metal is feasible, bringing stents without risk of late thrombosis one step closer to the patient.

  1. Adding functionality with additive manufacturing: Fabrication of titanium-based antibiotic eluting implants

    International Nuclear Information System (INIS)

    Cox, Sophie C.; Jamshidi, Parastoo; Eisenstein, Neil M.; Webber, Mark A.; Hassanin, Hany; Attallah, Moataz M.; Shepherd, Duncan E.T.; Addison, Owen; Grover, Liam M.

    2016-01-01

    Additive manufacturing technologies have been utilised in healthcare to create patient-specific implants. This study demonstrates the potential to add new implant functionality by further exploiting the design flexibility of these technologies. Selective laser melting was used to manufacture titanium-based (Ti-6Al-4V) implants containing a reservoir. Pore channels, connecting the implant surface to the reservoir, were incorporated to facilitate antibiotic delivery. An injectable brushite, calcium phosphate cement, was formulated as a carrier vehicle for gentamicin. Incorporation of the antibiotic significantly (p = 0.01) improved the compressive strength (5.8 ± 0.7 MPa) of the cement compared to non-antibiotic samples. The controlled release of gentamicin sulphate from the calcium phosphate cement injected into the implant reservoir was demonstrated in short term elution studies using ultraviolet-visible spectroscopy. Orientation of the implant pore channels were shown, using micro-computed tomography, to impact design reproducibility and the back-pressure generated during cement injection which ultimately altered porosity. The amount of antibiotic released from all implant designs over a 6 hour period (< 28% of the total amount) were found to exceed the minimum inhibitory concentrations of Staphylococcus aureus (16 μg/mL) and Staphylococcus epidermidis (1 μg/mL); two bacterial species commonly associated with periprosthetic infections. Antibacterial efficacy was confirmed against both bacterial cultures using an agar diffusion assay. Interestingly, pore channel orientation was shown to influence the directionality of inhibition zones. Promisingly, this work demonstrates the potential to additively manufacture a titanium-based antibiotic eluting implant, which is an attractive alternative to current treatment strategies of periprosthetic infections. - Highlights: • Titanium implants were additively manufactured with surface connected reservoirs. • Implants

  2. Drug-eluting stents versus bare-metal stents for acute coronary syndrome

    DEFF Research Database (Denmark)

    Feinberg, Joshua; Nielsen, Emil Eik; Greenhalgh, Janette

    2017-01-01

    -EXPANDED, and BIOSIS from their inception to January 2017. We also searched two clinical trials registers, the European Medicines Agency and the US Food and Drug Administration databases, and pharmaceutical company websites. In addition, we searched the reference lists of review articles and relevant trials. SELECTION...... CRITERIA: Randomised clinical trials assessing the effects of drug-eluting stents versus bare-metal stents for acute coronary syndrome. We included trials irrespective of publication type, status, date, or language. DATA COLLECTION AND ANALYSIS: We followed our published protocol and the methodological...

  3. Application of rotational atherectomy in the drug-eluting stent era

    Science.gov (United States)

    Chen, Chun-Chi; Hsieh, I-Chang

    2013-01-01

    Rotational atherectomy (RA) was introduced in the interventional arena in 1988 as a dedicated device for calcified lesions. Due to the complexity of the technique, the development of alternative methods such as the cutting balloon procedure, and the high restenosis rate of subsequent bare metal stenting in long lesions, its use had later declined. However, with the increasing use of drug-eluting stents (DES) and the aggressive treatment of longer lesions, the number of procedure performed with RA has increased significantly again in recent years. In this article, we reviewed the application of RA in DES era. PMID:24133506

  4. Bradycardia Associated With Drug-Eluting Beads Loaded With Irinotecan (DEBIRI) Infusion for Colorectal Liver Metastases

    International Nuclear Information System (INIS)

    Pua, Uei

    2013-01-01

    Intra-arterial injection of drug-eluting beads loaded with irinotecan (DEBIRI) is a new treatment option being investigated, with encouraging results, for unresectable colorectal liver metastases that are refractory to systemic chemotherapy (Martin et al., Ann Surg Oncol 18:192–198, 2011). Toxicity related to DEBIRI has also been described (Martin et al., Cardiovasc Intervent Radiol 33:960–966, 2010). Nevertheless, experience and literature related to DEBIRI remain limited, and experience with this treatment is expected to increase. The purpose of this article is to describe bradycardia occurring during DEBIRI administration, which has not been reported thus far.

  5. Drug eluting stents and modern stent technologies for in-stent restenosis.

    Science.gov (United States)

    Werner, Martin

    2017-08-01

    The implantation of metallic stents has become a standard procedure to improve the outcome after angioplasty of peripheral vessels. However, the occurrence of in-stent restenosis is hampering the long-term efficacy of these procedures and is associated with re-occurrence of symptoms. The optimal treatment modality for in-stent-restenosis in the peripheral vasculature is not well examined. This review discusses the existing evidence for the treatment of in-stent restenosis with drug eluting stents and modern stent technologies.

  6. Anti-Inflammatory Effect of Gallic Acid-Eluting Stent in a Porcine Coronary Restenosis Model

    Science.gov (United States)

    Seob Lim, Kyung; Park, Jun-Kyu; Ho Jeong, Myung; Ho Bae, In; Sung Park, Dae; Won Shim, Jae; Ha Kim, Jung; Kuk Kim, Hyun; Soo Kim, Sung; Sun Sim, Doo; Joon Hong, Young; Han Kim, Ju; Ahn, Youngkeun

    2018-01-01

    Background Gallic acid (3,4,5-trihydroxybenzoic acid) is a natural polyphenol and strong natural antioxidant found abundantly in red wine and green tea. The aim of this study was to examine the anti-inflammatory effect of a novel gallic acid-eluting stent in a porcine coronary restenosis model. Methods Fifteen pigs were randomized into three groups; in which a total of 30 coronary arteries (10 in each group) were implanted with gallic acid-eluting stents (GESs, n = 10), gallic acid and sirolimus-eluting stents (GSESs, n = 10), or sirolimus-eluting stents (SESs, n = 10). Histopathologic analysis was performed 28 days after stenting. Results There were no significant differences in injury score and fibrin score among the groups, however there were significant differences in the internal elastic lamina (4.0 ± 0.83 mm2 in GES vs. 3.0 ± 0.53 mm2 in GSES vs. 4.6 ± 1.43 mm2 in SES, p < 0.0001), lumen area (2.3 ± 0.49 mm2 in GES vs. 1.9 ± 0.67 mm2 in GSES vs. 2.9 ± 0.56 mm2 in SES, p < 0.0001), neointimal area (1.7 ± 0.63 mm2 in GES vs. 1.1 ± 0.28 mm2 in GSES vs. 1.7 ± 1.17 mm2 in SES, p < 0.05), and percent area of stenosis (42.4% ± 9.22% in GES vs. 38.2% ± 12.77% in GSES vs. 33.9% ± 15.64% in SES, p < 0.05). The inflammation score was significantly lower in the GES and GSES groups compared to that in the SES group [1.0 (range: 1.0 to 2.0) in GES vs. 1.0 (range: 1.0 to 1.0) in GSES vs. 1.5 (range: 1.0 to 3.0) in SES, p < 0.05]. Conclusions The GES group had a greater percent area of stenosis than the SES group. Although gallic acid in the GES and GSES groups did not show a synergistic effect in suppressing neointimal hyperplasia, it resulted in greater inhibition of the inflammatory reaction in the porcine coronary restenosis model than in the SES group. PMID:29844643

  7. Detection of UVR-induced DNA damage in mouse epidermis in vivo using alkaline elution

    International Nuclear Information System (INIS)

    Kinley, J.S.; Moan, J.; Brunborg, G.

    1995-01-01

    Alkaline elution has been used to detect ultraviolet radiation (UVR)-induced DNA damage in the epidermis of C3H/Tif hr/hr mice. This technique detects DNA damage in the form of single-strand breaks and alkali-labile sites (SSB) formed directly by UVA (320-400 nm) or indirectly by UVB (280-320 nm). The latter induces DNA damage such as cyclobutane pyrimidine dimers and pyrimidine-pyrimidone (6-4)-photoproducts, which are then converted into transient SSB by cellular endonucleases, during nucleotide excision repair (NER). (Author)

  8. Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold

    Science.gov (United States)

    Kumar, Sachin; Chatterjee, Kaushik

    2015-01-01

    The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(ε-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium

  9. Bradycardia Associated With Drug-Eluting Beads Loaded With Irinotecan (DEBIRI) Infusion for Colorectal Liver Metastases

    Energy Technology Data Exchange (ETDEWEB)

    Pua, Uei, E-mail: druei@yahoo.com [Tan Tock Seng Hospital, Department of Diagnostic Radiology (Singapore)

    2013-06-15

    Intra-arterial injection of drug-eluting beads loaded with irinotecan (DEBIRI) is a new treatment option being investigated, with encouraging results, for unresectable colorectal liver metastases that are refractory to systemic chemotherapy (Martin et al., Ann Surg Oncol 18:192-198, 2011). Toxicity related to DEBIRI has also been described (Martin et al., Cardiovasc Intervent Radiol 33:960-966, 2010). Nevertheless, experience and literature related to DEBIRI remain limited, and experience with this treatment is expected to increase. The purpose of this article is to describe bradycardia occurring during DEBIRI administration, which has not been reported thus far.

  10. Impact of polymer formulations on neointimal proliferation after zotarolimus-eluting stent with different polymers: insights from the RESOLUTE trial.

    Science.gov (United States)

    Waseda, Katsuhisa; Ako, Junya; Yamasaki, Masao; Koizumi, Tomomi; Sakurai, Ryota; Hongo, Yoichiro; Koo, Bon-Kwon; Ormiston, John; Worthley, Stephen G; Whitbourn, Robert J; Walters, Darren L; Meredith, Ian T; Fitzgerald, Peter J; Honda, Yasuhiro

    2011-06-01

    Polymer formulation may affect the efficacy of drug-eluting stents. Resolute, Endeavor, and ZoMaxx are zotarolimus-eluting stents with different stent platforms and different polymer coatings and have been tested in clinical trials. The aim of this analysis was to compare the efficacy of zotarolimus-eluting stents with different polymers. Data were obtained from the first-in man trial or first randomized trials of each stent, The Clinical RESpOnse EvaLUation of the MedTronic Endeavor CR ABT-578 Eluting Coronary Stent System in De Novo Native Coronary Artery Lesions (RESOLUTE), Randomized Controlled Trial to Evaluate the Safety and Efficacy of the Medtronic AVE ABT-578 Eluting Driver Coronary Stent in De Novo Native Coronary Artery Lesions (ENDEAVOR II), and ZoMaxx I trials. Follow-up intravascular ultrasound analyses (8 to 9 months of follow-up) were possible in 353 patients (Resolute: 88, Endeavor: 98, ZoMaxx: 82, Driver: 85). Volume index (volume/stent length) was obtained for vessel, stent, lumen, peristent plaque, and neointima. Cross-sectional narrowing was defined as neointimal area divided by stent area (%). Neointima-free frame ratio was calculated as the number of frames without intravascular ultrasound-detectable neointima divided by the total number of frames within the stent. At baseline, vessel, lumen, and peristent plaque volume index were not significantly different among the 4 stent groups. At follow-up, percent neointimal obstruction was significantly lower in Resolute compared with Endeavor, ZoMaxx, and Driver (Resolute: 3.7±4.0, Endeavor: 17.5±10.1, ZoMaxx: 14.6±8.1, Driver: 29.4±17.2%; Ppolymer used in Resolute independently correlated with neointimal suppression among 3 zotarolimus-eluting stents. The different polymer formulations significantly affect the relative amount of neointima for zotarolimus-eluting stents. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00248079.

  11. A sirolimus-eluting bioabsorbable polymer-coated stent (MiStent) versus an everolimus-eluting durable polymer stent (Xience) after percutaneous coronary intervention (DESSOLVE III): a randomised, single-blind, multicentre, non-inferiority, phase 3 trial.

    Science.gov (United States)

    de Winter, Robbert J; Katagiri, Yuki; Asano, Taku; Milewski, Krzysztof P; Lurz, Philipp; Buszman, Pawel; Jessurun, Gillian A J; Koch, Karel T; Troquay, Roland P T; Hamer, Bas J B; Ophuis, Ton Oude; Wöhrle, Jochen; Wyderka, Rafał; Cayla, Guillaume; Hofma, Sjoerd H; Levesque, Sébastien; Żurakowski, Aleksander; Fischer, Dieter; Kośmider, Maciej; Goube, Pascal; Arkenbout, E Karin; Noutsias, Michel; Ferrari, Markus W; Onuma, Yoshinobu; Wijns, William; Serruys, Patrick W

    2018-02-03

    MiStent is a drug-eluting stent with a fully absorbable polymer coating containing and embedding a microcrystalline form of sirolimus into the vessel wall. It was developed to overcome the limitation of current durable polymer drug-eluting stents eluting amorphous sirolimus. The clinical effect of MiStent sirolimus-eluting stent compared with a durable polymer drug-eluting stents has not been investigated in a large randomised trial in an all-comer population. We did a randomised, single-blind, multicentre, phase 3 study (DESSOLVE III) at 20 hospitals in Germany, France, Netherlands, and Poland. Eligible participants were any patients aged at least 18 years who underwent percutaneous coronary intervention in a lesion and had a reference vessel diameter of 2·50-3·75 mm. We randomly assigned patients (1:1) to implantation of either a sirolimus-eluting bioresorbable polymer stent (MiStent) or an everolimus-eluting durable polymer stent (Xience). Randomisation was done by local investigators via web-based software with random blocks according to centre. The primary endpoint was a non-inferiority comparison of a device-oriented composite endpoint (DOCE)-cardiac death, target-vessel myocardial infarction, or clinically indicated target lesion revascularisation-between the groups at 12 months after the procedure assessed by intention-to-treat. A margin of 4·0% was defined for non-inferiority of the MiStent group compared with the Xience group. All participants were included in the safety analyses. This trial is registered with ClinicalTrials.gov, number NCT02385279. Between March 20, and Dec 3, 2015, we randomly assigned 1398 patients with 2030 lesions; 703 patients with 1037 lesions were assigned to MiStent, of whom 697 received the index procedure, and 695 patients with 993 lesions were asssigned to Xience, of whom 690 received the index procedure. At 12 months, the primary endpoint had occurred in 40 patients (5·8%) in the sirolimus-eluting stent group and in 45

  12. Isolation of four phenolic compounds from Mangifera indica L. flowers by using normal phase combined with elution extrusion two-step high speed countercurrent chromatography.

    Science.gov (United States)

    Shaheen, Nusrat; Lu, Yanzhen; Geng, Ping; Shao, Qian; Wei, Yun

    2017-03-01

    Two-step high speed countercurrent chromatography method, following normal phase and elution-extrusion mode of operation by using selected solvent systems, was introduced for phenolic compounds separation. Phenolic compounds including gallic acid, ethyl gallate, ethyl digallate and ellagic acid were separated from the ethanol extract of mango (Mangifera indica L.) flowers for the first time. In the first step, gallic acid of 3.7mg and ethyl gallate of 3.9mg with the purities of 98.87% and 99.55%, respectively, were isolated by using hexane-ethylacetate-methanol-water (4:6:4:6, v/v) in normal phase high speed countercurrent chromatography from 200mg of crude extract, while ethyl digallate and ellagic acid were collected in the form of mixture fraction. In the second step, further purification of the mixture was carried out with the help of another selected solvent system of dichloromethane-methanol-water (4:3:2, v/v) following elusion-extrusion mode of operation. Ethyl digallate of 3.8mg and ellagic acid of 5.7mg were separated well with high purities of 98.68% and 99.71%, respectively. The separated phenolic compounds were identified and confirmed by HPLC, UPLC-QTOF/ESI-MS, 1 H and 13 C NMR spectrometric analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. On Localized Vapor Pressure Gradients Governing Condensation and Frost Phenomena.

    Science.gov (United States)

    Nath, Saurabh; Boreyko, Jonathan B

    2016-08-23

    Interdroplet vapor pressure gradients are the driving mechanism for several phase-change phenomena such as condensation dry zones, interdroplet ice bridging, dry zones around ice, and frost halos. Despite the fundamental nature of the underlying pressure gradients, the majority of studies on these emerging phenomena have been primarily empirical. Using classical nucleation theory and Becker-Döring embryo formation kinetics, here we calculate the pressure field for all possible modes of condensation and desublimation in order to gain fundamental insight into how pressure gradients govern the behavior of dry zones, condensation frosting, and frost halos. Our findings reveal that in a variety of phase-change systems the thermodynamically favorable mode of nucleation can switch between condensation and desublimation depending upon the temperature and wettability of the surface. The calculated pressure field is used to model the length of a dry zone around liquid or ice droplets over a broad parameter space. The long-standing question of whether the vapor pressure at the interface of growing frost is saturated or supersaturated is resolved by considering the kinetics of interdroplet ice bridging. Finally, on the basis of theoretical calculations, we propose that there exists a new mode of frost halo that is yet to be experimentally observed; a bimodal phase map is developed, demonstrating its dependence on the temperature and wettability of the underlying substrate. We hope that the model and predictions contained herein will assist future efforts to exploit localized vapor pressure gradients for the design of spatially controlled or antifrosting phase-change systems.

  14. Classical convective energy transport in large gradient regions

    International Nuclear Information System (INIS)

    Hinton, F.L.

    1996-01-01

    Large gradients in density and temperature occur near the edge in H-mode plasmas and in the core of tokamak plasmas with negative central shear. Transport in these regions may be comparable to neoclassical. Standard neoclassical theory does not apply when the gradient lengths are comparable to an ion orbit excursion, or banana width. A basic question for neoclassical transport in large gradient regions is: do ion-ion collisions drive particle transport? Near the plasma edge in H-mode, where ion orbit loss requires that the ion energy transport be convective, neoclassical particle transport due to ion-ion collisions may play an important role. In negative central shear plasmas, where transport is inferred to be near neoclassical, it is important to have accurate predictions for the neoclassical rate of energy and particle transport. A simple 2-D slab model has been used, with a momentum-conserving collision operator, to show that ion-ion collisions do drive particle transport. When the gradients are large, the open-quotes field particleclose quotes contribution to the particle flux is non-local, and does not cancel the open-quotes test particleclose quotes contribution, which is local. Solutions of the kinetic equation are found which show that the steepness of the density profile, for increasing particle flux, is limited by orbit averaging. The gradient length is limited by the thermal gyroradius, and the convective energy flux is independent of ion temperature. This will allow an ion thermal runaway to occur, if there are no other ion energy loss mechanisms

  15. Hydraulic gradients in rock aquifers

    International Nuclear Information System (INIS)

    Dahlblom, P.

    1992-05-01

    This report deals with fractured rock as a host for deposits of hazardous waste. In this context the rock, with its fractures containing moving groundwater, is called the geological barrier. The desired properties of the geological barrier are low permeability to water, low hydraulic gradients and ability to retain matter dissolved in the water. The hydraulic gradient together with the permeability and the porosity determines the migration velocity. Mathematical modelling of the migration involves calculation of the water flow and the hydrodynamic dispersion of the contaminant. The porous medium approach can be used to calculate mean flow velocities and hydrodynamic dispersion of a large number of fractures are connected, which means that a large volume have to be considered. It is assumed that the porous medium approach can be applied, and a number of idealized examples are shown. It is assumed that the groundwater table is replenished by percolation at a constant rate. One-dimensional analytical calculations show that zero hydraulic gradients may exist at relatively large distance from the coast. Two-dimensional numerical calculations show that it may be possible to find areas with low hydraulic gradients and flow velocities within blocks surrounded by areas with high hydraulic conductivity. (au)

  16. A theory of gradient analysis

    NARCIS (Netherlands)

    Braak, ter C.J.F.

    1988-01-01

    The theory of gradient analysis is presented in this chapter, in which the heuristic techniques are integrated with regression, calibration, ordination and constrained ordination as distinct, well-defined statistical problems. The various techniques used for each type of problem are classified into

  17. Compositional gradients in Gramineae genes

    DEFF Research Database (Denmark)

    Wong, Gane Ka-Shu; Wang, Jun; Tao, Lin

    2002-01-01

    In this study, we describe a property of Gramineae genes, and perhaps all monocot genes, that is not observed in eudicot genes. Along the direction of transcription, beginning at the junction of the 5'-UTR and the coding region, there are gradients in GC content, codon usage, and amino-acid usage...

  18. Orderings for conjugate gradient preconditionings

    Science.gov (United States)

    Ortega, James M.

    1991-01-01

    The effect of orderings on the rate of convergence of the conjugate gradient method with SSOR or incomplete Cholesky preconditioning is examined. Some results also are presented that help to explain why red/black ordering gives an inferior rate of convergence.

  19. Color gradients in elliptical galaxies

    International Nuclear Information System (INIS)

    Franx, M.; Illingworth, G.

    1990-01-01

    The relationship of the color gradients within ellipticals and the color differences between them are studied. It is found that the local color appears to be strongly related to the escape velocity. This suggests that the local escape velocity is the primary factor that determines the metallicity of the stellar population. Models with and without dark halos give comparable results. 27 refs

  20. Chronic Kidney Disease in the Second-Generation Drug-Eluting Stent Era: Pooled Analysis of the Korean Multicenter Drug-Eluting Stent Registry.

    Science.gov (United States)

    Lee, Joo Myung; Kang, Jeehoon; Lee, Euijae; Hwang, Doyeon; Rhee, Tae-Min; Park, Jonghanne; Kim, Hack-Lyoung; Lee, Sang Eun; Han, Jung-Kyu; Yang, Han-Mo; Park, Kyung Woo; Na, Sang-Hoon; Kang, Hyun-Jae; Koo, Bon-Kwon; Kim, Hyo-Soo

    2016-10-24

    The purpose of this study was to evaluate the clinical impact of chronic kidney disease (CKD) on clinical outcomes in contemporary practice of percutaneous coronary intervention (PCI) using second-generation drug-eluting stents (DES). Although second-generation DES have improved the safety and efficacy issues in PCI, data regarding the performance of second-generation DES in patients with CKD are still limited. We performed a patient-level pooled analysis on 12,426 patients undergoing PCI using second-generation DES from the Korean Multicenter Drug-Eluting Stent Registry. Endpoints were stent-oriented outcomes (target lesion failure [TLF]) and patient-oriented composite outcomes (POCO) during a median follow-up of 35 months. CKD patients were stratified by the estimated glomerular filtration rate (eGFR) from mild CKD to end-stage renal disease patients, and by the coexistence of diabetes mellitus (DM). A total of 2,927 patients had CKD (23.6%), who showed a significantly higher risk of TLF (adjusted hazard ratio [HR adjust ]: 1.50; 95% confidence interval [CI]: 1.21 to 1.86) and POCO (HR adjust 1.34; 95% CI: 1.17 to 1.55) compared to patients with preserved renal function. Stratified analysis by eGFR showed that TLF was not increased in the mild to moderate CKD, whereas severe CKD and dialysis-dependent patients showed significantly higher risk of TLF (HR adjust 2.44; 95% CI: 1.54 to 3.86; HR adjust 3.58; 95% CI: 2.52 to 5.08, respectively). The eGFR threshold of increased clinical events was 40 to 45 ml/min/1.73 m 2 . Among CKD patients, DM CKD patients showed a higher incidence of TLF compared to non-DM CKD patients (HR adjust : 1.82; 95% CI: 1.32 to 2.52), driven by the increase in target vessel-related events. In the era of second-generation DES, CKD patients were at a significantly higher risk of clinical outcomes only in severe CKD and end-stage renal disease patients. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All

  1. Zotarolimus-eluting Resolute Integrity versus everolimus-eluting Xience Xpedition stents in the management of very long (>30 mm) de novo coronary artery stenosis

    Energy Technology Data Exchange (ETDEWEB)

    Patra, Soumya, E-mail: dr_soumyapatra@rediffmail.com; Chakraborty, Rabindra Nath; Pande, Arindam; Banerjee, Suvro; Jena, Manabhanjan; Mandal, Prakash Chandra; De, Swapan Kumar; Khan, Aftab; Das, Sankha Suvro; Ghosh, Debashish; Nag, Raja

    2017-04-15

    Background: Procedural and clinical outcomes in patients with very long (>30 mm) coronary lesions who underwent stent-based percutaneous coronary interventions are still unfavorable. Therefore, we compared the relative efficacy and safety of resolute zotarolimus-eluting stents (R-ZES) and Xpedition everolimus-eluting stents (X-EES) for patients with de novo very long coronary lesions. Methods: This comparative single-centre, retrospective study compared long R-ZES and X-EES in consecutive patients admitted with very long (≥30 mm) native ACC/AHA type C coronary lesions in 2014. All patients were followed up clinically at 1, 3, 6 and 12 months. In this study, only symptom-driven angiogram was advised. The study end point was to evaluate immediate procedural success and one-year rate of target lesion failure (TLF), which is a composite of cardiac death, target lesion myocardial infarction, or target lesion revascularization (TLR). Results: Total number of patients enrolled in this study was 185 (R-ZES = 107; X-EES = 78). The baseline characteristics and post procedural success rate were similar between R-ZES and X-EES groups, including the post stenting lesion lengths (36.6 ± 1.92 mm vs 40.71 ± 6.175 mm, P = 0.09). At 12-month follow-up, there were no significant between-group differences in the rate of adverse clinical events (death, myocardial infarction, stent thrombosis, target lesion revascularization, and composite outcomes). Procedural success was achieved in 94% in R-ZES group and 93% in X-EES group (P = 0.24). The incidence of TLF was 5% in R-ZES and 4% in X-EES groups (HR-1.25; 95% CI-0.86-5.6; P = 0.19). Conclusion: Patients with de novo long coronary artery disease, R-ZES implantation showed similar clinical outcome as compared with X-EES implantation. - Highlights: • This is the first study comparing between R-ZES (Resolute Integrity) and X-EES (Xience Xpedition) used in PCI for long coronary artery disease. Here, single stent length of more than 30

  2. Biodegradable polymer sirolimus-eluting stents versus durable polymer everolimus-eluting stents for primary percutaneous coronary revascularisation of acute myocardial infarction.

    Science.gov (United States)

    Pilgrim, Thomas; Piccolo, Raffaele; Heg, Dik; Roffi, Marco; Tüller, David; Vuilliomenet, André; Muller, Olivier; Cook, Stéphane; Weilenmann, Daniel; Kaiser, Christoph; Jamshidi, Peiman; Khattab, Ahmed A; Taniwaki, Masanori; Rigamonti, Fabio; Nietlispach, Fabian; Blöchlinger, Stefan; Wenaweser, Peter; Jüni, Peter; Windecker, Stephan

    2016-12-10

    Our aim was to compare the safety and efficacy of a novel, ultrathin strut, biodegradable polymer sirolimus-eluting stent (BP-SES) with a thin strut, durable polymer everolimus-eluting stent (DP-EES) in a pre-specified subgroup of patients with acute ST-segment elevation myocardial infarction (STEMI) enrolled in the BIOSCIENCE trial. The BIOSCIENCE trial is an investigator-initiated, single-blind, multicentre, randomised non-inferiority trial (NCT01443104). Randomisation was stratified according to the presence or absence of STEMI. The primary endpoint, target lesion failure (TLF), is a composite of cardiac death, target vessel myocardial infarction, and clinically indicated target lesion revascularisation within 12 months. Between February 2012 and May 2013, 407 STEMI patients were randomly assigned to treatment with BP-SES or DP-EES. At one year, TLF occurred in seven (3.4%) patients treated with BP-SES and 17 (8.8%) patients treated with DP-EES (RR 0.38, 95% CI: 0.16-0.91, p=0.024). Rates of cardiac death were 1.5% in the BP-SES group and 4.7% in the DP-EES group (RR 0.31, 95% CI: 0.08-1.14, p=0.062); rates of target vessel myocardial infarction were 0.5% and 2.6% (RR 0.18, 95% CI: 0.02-1.57, p=0.082), respectively, and rates of clinically indicated target lesion revascularisation were 1.5% in the BP-SES group versus 2.1% in the DP-EES group (RR 0.69, 95% CI: 0.16-3.10, p=0.631). There was no difference in the risk of definite stent thrombosis. In this pre-specified subgroup analysis, BP-SES was associated with a lower rate of target lesion failure at one year compared to DP-EES in STEMI patients. These findings require confirmation in a dedicated STEMI trial.

  3. H-mode physics

    International Nuclear Information System (INIS)

    Itoh, Sanae.

    1991-06-01

    After the discovery of the H-mode in ASDEX ( a tokamak in Germany ) the transition between the L-mode ( Low confinement mode ) and H-mode ( High confinement mode ) has been observed in many tokamaks in the world. The H-mode has made a breakthrough in improving the plasma parameters and has been recognized to be a universal phenomena. Since its discovery, the extensive studies both in experiments and in theory have been made. The research on H-mode has been casting new problems of an anomalous transport across the magnetic surface. This series of lectures will provide a brief review of experiments for explaining H-mode and a model theory of H-mode transition based on the electric field bifurcation. If the time is available, a new theoretical model of the temporal evolution of the H-mode will be given. (author)

  4. Chemical composition separation of a propylene-ethylene random copolymer by high temperature solvent gradient interaction chromatography.

    Science.gov (United States)

    Liu, Yonggang; Phiri, Mohau Justice; Ndiripo, Anthony; Pasch, Harald

    2017-11-03

    A propylene-ethylene random copolymer was fractionated by preparative temperature rising elution fractionation (TREF). The structural heterogeneity of the bulk sample and its TREF fractions was studied by high temperature liquid chromatography with a solvent gradient elution from 1-decanol to 1,2,4-trichlorobenzene. HPLC alone cannot resolve those propylene-ethylene copolymers with high ethylene content in the bulk sample, due to their low weight fractions in the bulk sample and a small response factor of these components in the ELSD detector, as well as their broad chemical composition distribution. These components can only be detected after being separated and enriched by TREF followed by HPLC analysis. Chemical composition separations were achieved for TREF fractions with average ethylene contents between 2.1 and 22.0mol%, showing that copolymers with higher ethylene contents were adsorbed stronger in the Hypercarb column and eluted later. All TREF fractions, except the 40°C fraction, were relatively homogeneous in both molar mass and chemical composition. The 40°C fraction was rather broad in both molar mass and chemical composition distributions. 2D HPLC showed that the molar masses of the components containing more ethylene units were getting lower for the 40°C fraction. HPLC revealed and confirmed that co-crystallization influences the separation in TREF of the studied propylene-ethylene copolymer. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. High-confinement-mode edge stability of Alcator C-mod plasmas

    International Nuclear Information System (INIS)

    Mossessian, D.A.; Snyder, P.; Hubbard, A.; Hughes, J.W.; Greenwald, M.; La Bombard, B.; Snipes, J.A.; Wolfe, S.; Wilson, H.

    2003-01-01

    For steady state high-confinement-mode (H-mode) operation, a relaxation mechanism is required to limit build-up of the edge gradient and impurity content. Alcator C-Mod [Hutchinson et al., Phys. Plasmas 1, 1511 (1994)] sees two such mechanisms--EDA (enhanced D-alpha H mode) and grassy ELMs (edge localized modes), but not large type I ELMs. In EDA the edge relaxation is provided by an edge localized quasicoherent (QC) electromagnetic mode that exists at moderate pedestal temperature T 95 >3.5, and does not limit the buildup of the edge pressure gradient. The q boundary of the operational space of the mode depends on plasma shape, with the q 95 limit moving down with increasing plasma triangularity. At high edge pressure gradients and temperatures the mode is replaced by broadband fluctuations ( f<50 kHz) and small irregular ELMs are observed. Ideal MHD (magnetohydrodynamic) stability analysis that includes both pressure and current driven edge modes shows that the discharges where the QC mode is observed are stable. The ELMs are identified as medium n (10< n<50) coupled peeling/ballooning modes. The predicted stability boundary of the modes as a function of pedestal current and pressure gradient is reproduced in experimental observations. The measured dependence of the ELMs' threshold and amplitude on plasma triangularity is consistent with the results of ideal MHD analysis performed with the linear stability code ELITE [Wilson et al., Phys. Plasmas 9, 1277 (2002)

  6. Alpha particle destabilization of the TAE modes

    International Nuclear Information System (INIS)

    Cheng, C.Z.

    1991-01-01

    The high frequency, low mode number toroidicity-induced Alfven eigenmodes (TAE) are shown to be driven unstable by the circulating and/or trapped α-particles through the wave-particle resonances. For a poloidal harmonic to satisfy the resonance condition it requires that the α-particle birth speed v α ≥ v A /(2|m-nq|), where v A is the Alfven speed, m is the poloidal mode number, and n is the toroidal mode number. To destabilize the TAE modes, the inverse Landau damping associated with the α-particle pressure gradient free energy must overcome the velocity space Landau damping due to both the slowing-down α-particle and the core Maxwellian electron and ion distributions. Stability criteria in terms of the α-particle beta β α , α-particle pressure gradient parameter (ω * /ω A ) (ω * is the α-particle diamagnetic drift frequency), and (v α /v A ) parameters are presented for TFTR, CIT, and ITER tokamaks. The volume averaged α-particle beta threshold for TAE instability also depends sensitively on the core electron and ion temperature. Typically the volume averaged α-particle beta threshold is in the order of 10 -4 if the continuum damping effect is absent. Typical growth rates of the n = 1 TAE mode can be in the order of 10 -2 ω A , where ω A = v A /qR. Stability of higher n TAE modes is also studied. Other types of global Alfven waves are stable due to sideband mode continuum damping resulting from toroidal coupling effects. If the Alfven continuum gap does not exist across the whole minor radius, continuum damping exists for some poloidal harmonics. The continuum damping effect is studied by employing both a resistive MHD stability code (NOVA-R) and an analytical matching method, and the results are presented. 1 ref

  7. Hydrodynamization and transient modes of expanding plasma in kinetic theory

    CERN Document Server

    Heller, Michal P.; Spalinski, Michal

    2016-01-01

    We study the transition to hydrodynamics in a weakly-coupled model of quark-gluon plasma given by kinetic theory in the relaxation time approximation. Our studies uncover qualitative similarities to the results on hydrodynamization in strongly coupled gauge theories. In particular, we demonstrate that the gradient expansion in this model has vanishing radius of convergence. The asymptotic character of the hydrodynamic gradient expansion is crucial for the recently discovered applicability of hydrodynamics at large gradients. Furthermore, the analysis of the resurgent properties of the series provides, quite remarkably, indication for the existence of a novel transient, damped oscillatory mode of expanding plasmas in kinetic theory.

  8. Elution behavior of poly(ethylene glycol) through poly(vinyl alcohol) gel column using several solvents as eluents

    International Nuclear Information System (INIS)

    Hirayama, Chuichi; Motozato, Yoshiaki; Matsumoto, Kazuaki.

    1983-01-01

    γ-Irradiated poly(vinyl alcohol) beads, which were sufficiently allowed to swell in water, were washed with methanol, and then were packed into column. Gel chromatography was performed using methanol, benzene, esters and ketones as eluents and poly(ethylene glycol) as a sample. When the elution was carried out using methanol and benzene as eluents, elution behavior of samples was ordinary. When ethyl formate, methyl acetate and ethyl propionate were used as eluents, samples were slightly adsorbed and the elution was delayed. In the case the elution was carried out using ethyl acetate, propyl acetate, butyl acetate and ethyl methyl ketone as eluents, samples were adsorbed strongly on the bed material, and the adsorption curve was analogous to the calibration curve using methanol as an eluent. Dried poly(vinyl alcohol) gel as a packing material, showed ordinary elution behaviors for the samples. The adsorption of poly(ethylene glycol) on the present bed material was attributed to the existence of hydrated water on poly(vinyl alcohol) gel matrix. (author)

  9. Methods for eluting radiocesium from zeolite ion exchange material in a column in the TMI-2 reactor containment building

    International Nuclear Information System (INIS)

    Knauer, J.B.; Campbell, D.O.; Collins, E.D.; King, L.J.

    1982-07-01

    Two alternative procedures were evaluated at Oak Ridge National Laboratory for potential use in eluting the radiocesium from Linde Ionsiv IE-95 zeolite in the pushcart ion exchange column in the TMI-2 containment building. The elution mechanism was iosotopic exchange of the radiocesium with stable cesium. Small zeolite ion exchange columns that had been loaded during ORNL tests of the Submerged Demineralizer System (SDS) flowsheet were eluted during these tests. One column was eluted using 0.25 M CsNO 3 , and a second column was eluted using 0.25 M CsH 2 BO 3 . Both eluent solutions were effective for removing the cesium. The 0.25 CsNO 3 eluent removed approx. 91% of the 137 Cs in 20 bed volumes and approx. 92% in 37.5 bed volumes. The 0.25 M CsH 2 BO 3 eluent removed approx. 82% of the 137 Cs in 20 bed volumes and approx. 85% in 40 bed volumes. In both cases, the radiation levels on the columns were reduced by a factor of approx. 30

  10. Elemental gradients in macrophytes from a reactor effluent gradient

    International Nuclear Information System (INIS)

    Grace, J.B.; Tilly, L.J.

    1978-01-01

    The tissues of submersed macrophtes from along the thermal gradient were analyzed for phosphorus to determine whether any pattern correspondent to standing crop distributions could be detected. Although water concentrations of phosphorus showed no detectable relationship to the thermal effluent, tissue concentrations of this element in submersed macrophytes declined with distance from the effluent entry point. The occurrence of this concentration pattern suggests that phosphorus availability is greater near the discharge. Because phosphorus is the element most often determined to limit aquatic productivity, its greater availability may partially account for the apparent enhancement of macrophte growth near the thermal discharge. A patter of macrophyte abundance which indicated enchancement related to the discharge gradient in the reactor-cooling reservoir, Par Pond is reported. Correlative data tended to implicate light and temperature as important in influencing the differential abundance pattern

  11. Measurement of M. luteus endonuclease-sensitive lesions by alkaline elution

    Energy Technology Data Exchange (ETDEWEB)

    Fornace, Jr, A J [National Cancer Inst., Bethesda, MD (USA). Lab. for Experimental Pathology

    1982-01-01

    The UV-endonuclease approach to detect DNA damage has been combined with the alkaline elution technique with a resultant marked increase in sensitivity compared to the conventional method using alkaline sedimentation. DNA from UV-irradiated cells was digested on an inert filter with an extract from Micrococcus luteus and then analyzed by alkaline elution. Endonuclease-sensitive sites (endo-sites) were measured after doses of 0.08-0.7 Jm/sup -2/ of UV-radiation. An estimate of endo-site production with UV radiation, 0.27 endo-sites/10/sup 8/ daltons of DNA/0.1 Jm/sup -2/, was similar to that usually seen at higher doses by others. With repair incubation, approx. 50% of the endo-sites were removed in 4 h by normal human fibroblasts after 0.2 or 0.4 Jm/sup -2/, no appreciable repair was seen in xeroderma pigmentosum fibroblasts from complementation group A after 24 h of repair incubation. No photoreaction of UV damage due to 0.4 Jm/sup -2/ was detected in normal human fibroblasts.

  12. Measurement of M. luteus endonuclease-sensitive lesions by alkaline elution

    International Nuclear Information System (INIS)

    Fornace, A.J. Jr.

    1982-01-01

    The UV-endonuclease approach to detect DNA damage has been combined with the alkaline elution technique with a resultant marked increase in sensitivity compared to the conventional method using alkaline sedimentation. DNA from UV-irradiated cells was digested on an inert filter with an extract from Micrococcus luteus and then analyzed by alkaline elution. Endonuclease-sensitive sites (endo-sites) were measured after doses of 0.08-0.7 Jm -2 of UV-radiation. An estimate of endo-site production with UV radiation, 0.27 endo-sites/10 8 daltons of DNA/0.1 Jm -2 , was similar to that usually seen at higher doses by others. With repair incubation, approx. 50% of the endo-sites were removed in 4 h by normal human fibroblasts after 0.2 or 0.4 Jm -2 , no appreciable repair was seen in xeroderma pigmentosum fibroblasts from complementation group A after 24 h of repair incubation. No photoreaction of UV damage due to 0.4 Jm -2 was detected in normal human fibroblasts. (orig./AJ)

  13. Adding functionality with additive manufacturing: Fabrication of titanium-based antibiotic eluting implants.

    Science.gov (United States)

    Cox, Sophie C; Jamshidi, Parastoo; Eisenstein, Neil M; Webber, Mark A; Hassanin, Hany; Attallah, Moataz M; Shepherd, Duncan E T; Addison, Owen; Grover, Liam M

    2016-07-01

    Additive manufacturing technologies have been utilised in healthcare to create patient-specific implants. This study demonstrates the potential to add new implant functionality by further exploiting the design flexibility of these technologies. Selective laser melting was used to manufacture titanium-based (Ti-6Al-4V) implants containing a reservoir. Pore channels, connecting the implant surface to the reservoir, were incorporated to facilitate antibiotic delivery. An injectable brushite, calcium phosphate cement, was formulated as a carrier vehicle for gentamicin. Incorporation of the antibiotic significantly (p=0.01) improved the compressive strength (5.8±0.7MPa) of the cement compared to non-antibiotic samples. The controlled release of gentamicin sulphate from the calcium phosphate cement injected into the implant reservoir was demonstrated in short term elution studies using ultraviolet-visible spectroscopy. Orientation of the implant pore channels were shown, using micro-computed tomography, to impact design reproducibility and the back-pressure generated during cement injection which ultimately altered porosity. The amount of antibiotic released from all implant designs over a 6hour period (additively manufacture a titanium-based antibiotic eluting implant, which is an attractive alternative to current treatment strategies of periprosthetic infections. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Drug-eluting Ti wires with titania nanotube arrays for bone fixation and reduced bone infection

    Science.gov (United States)

    Gulati, Karan; Aw, Moom Sinn; Losic, Dusan

    2011-10-01

    Current bone fixation technology which uses stainless steel wires known as Kirschner wires for fracture fixing often causes infection and reduced skeletal load resulting in implant failure. Creating new wires with drug-eluting properties to locally deliver drugs is an appealing approach to address some of these problems. This study presents the use of titanium [Ti] wires with titania nanotube [TNT] arrays formed with a drug delivery capability to design alternative bone fixation tools for orthopaedic applications. A titania layer with an array of nanotube structures was synthesised on the surface of a Ti wire by electrochemical anodisation and loaded with antibiotic (gentamicin) used as a model of bone anti-bacterial drug. Successful fabrication of TNT structures with pore diameters of approximately 170 nm and length of 70 μm is demonstrated for the first time in the form of wires. The drug release characteristics of TNT-Ti wires were evaluated, showing a two-phase release, with a burst release (37%) and a slow release with zero-order kinetics over 11 days. These results confirmed our system's ability to be applied as a drug-eluting tool for orthopaedic applications. The established biocompatibility of TNT structures, closer modulus of elasticity to natural bones and possible inclusion of desired drugs, proteins or growth factors make this system a promising alternative to replace conventional bone implants to prevent bone infection and to be used for targeted treatment of bone cancer, osteomyelitis and other orthopaedic diseases.

  15. Clinical results with the Resolute zotarolimus-eluting stent in total coronary occlusions

    DEFF Research Database (Denmark)

    Kelbæk, Henning; Holmvang, Lene; Richardt, Gert

    2015-01-01

    Aims: We conducted a pooled post hoc analysis (RESOLUTE All Comers and RESOLUTE International) of patients who had the Resolute® zotarolimus-eluting stent (R-ZES) implanted in revascularised total occlusions (TO) compared with patients treated with R-ZES for non-occluded lesions. Methods and resu......Aims: We conducted a pooled post hoc analysis (RESOLUTE All Comers and RESOLUTE International) of patients who had the Resolute® zotarolimus-eluting stent (R-ZES) implanted in revascularised total occlusions (TO) compared with patients treated with R-ZES for non-occluded lesions. Methods...... lesion revascularisation) and Academic Research Consortium definite or probable stent thrombosis. The rate of TLF at two years was not significantly different among patients in the CTO (9.1%), TO (9.8%), and no occlusion (10.4%) groups (log-rank p=0.800); neither were the components of TLF. Definite...... or probable stent thrombosis occurred more frequently in the TO group (2.8% vs. 1.2% in the CTO and 1.1% in the group with no occlusion, p=0.027). There were 10 late and six very late stent thrombosis events. Conclusions: Apart from a higher rate of stent thrombosis in patients with TO, patients with totally...

  16. Correlating cytotoxicity to elution behaviors of composite resins in term of curing kinetic.

    Science.gov (United States)

    Meng, Junquan; Yang, Huichuan; Cao, Man; Li, Lei; Cai, Qing

    2017-09-01

    Cytotoxicity of photocurable composite resins is a key issue for their safe use in dental restoration. Curing kinetic and elution behaviors of the composite resin would have decisive effects on its cytotoxicity. In this study, composite resins composed of bisphenol-glycidyl dimethacrylate (Bis-GMA), triethyleneglycol dimethacrylate (TEGDMA), camphorquinone (CQ), N,N-dimethylaminoethyl methacrylate (DMAEMA) and barium glass powders were prepared by setting the photoinitiators CQ/DMAEMA at 0.5wt%, 1wt% or 3wt% of the total weight of Bis-GMA/TEGDMA. The ratio of Bis-GMA/TEGDMA was 6:4, the ratio of CQ/DMAEMA was 1:1, and the incorporated inorganic powder was 75wt%. Then, curing kinetics were studied by using real-time Fourier transform infrared spectroscopy (FTIR) and photo-DSC (differential scanning calorimeter). Elution behaviors in both ethanol solution and deionized water were monitored by using liquid chromatogram/mass spectrometry (LC/MS). Cytotoxicity was evaluated by in vitro culture of L929 fibroblasts. Finally, they were all analyzed and correlated in terms of initiator contents. It was found that the commonly used 0.5wt% of photoinitiators was somewhat insufficient in obtaining composite resin with low cytotoxicity. Copyright © 2017. Published by Elsevier B.V.

  17. Enhanced fluidity liquid chromatography of inulin fructans using ternary solvent strength and selectivity gradients.

    Science.gov (United States)

    Bennett, Raffeal; Olesik, Susan V

    2018-01-25

    The value of exploring selectivity and solvent strength ternary gradients in enhanced fluidity liquid chromatography (EFLC) is demonstrated for the separation of inulin-type fructans from chicory. Commercial binary pump systems for supercritical fluid chromatography only allow for the implementation of ternary solvent strength gradients which can be restrictive for the separation of polar polymeric analytes. In this work, a custom system was designed to extend the capability of EFLC to allow tuning of selectivity or solvent strength in ternary gradients. Gradient profiles were evaluated using the Berridge function (RF 1 ), normalized resolution product (NRP), and gradient peak capacity (P c ). Selectivity gradients provided the separation of more analytes over time. The RF 1 function showed favor to selectivity gradients with comparable P c to that of solvent strength gradients. NRP did not strongly correlate with P c or RF 1 score. EFLC with the hydrophilic interaction chromatography, HILIC, separation mode was successfully employed to separate up to 47 fructan analytes in less than 25 min using a selectivity gradient. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Gyrokinetic Stability Studies of the Microtearing Mode in the National Spherical Torus Experiment H-mode

    International Nuclear Information System (INIS)

    Baumgaertel J.A., Redi M.H., Budny R.V., Rewoldt G., Dorland W.

    2005-01-01

    Insight into plasma microturbulence and transport is being sought using linear simulations of drift waves on the National Spherical Torus Experiment (NSTX), following a study of drift wave modes on the Alcator C-Mod Tokamak. Microturbulence is likely generated by instabilities of drift waves, which cause transport of heat and particles. Understanding this transport is important because the containment of heat and particles is required for the achievement of practical nuclear fusion. Microtearing modes may cause high heat transport through high electron thermal conductivity. It is hoped that microtearing will be stable along with good electron transport in the proposed low collisionality International Thermonuclear Experimental Reactor (ITER). Stability of the microtearing mode is investigated for conditions at mid-radius in a high density NSTX high performance (H-mode) plasma, which is compared to the proposed ITER plasmas. The microtearing mode is driven by the electron temperature gradient, and believed to be mediated by ion collisions and magnetic shear. Calculations are based on input files produced by TRXPL following TRANSP (a time-dependent transport analysis code) analysis. The variability of unstable mode growth rates is examined as a function of ion and electron collisionalities using the parallel gyrokinetic computational code GS2. Results show the microtearing mode stability dependence for a range of plasma collisionalities. Computation verifies analytic predictions that higher collisionalities than in the NSTX experiment increase microtearing instability growth rates, but that the modes are stabilized at the highest values. There is a transition of the dominant mode in the collisionality scan to ion temperature gradient character at both high and low collisionalities. The calculations suggest that plasma electron thermal confinement may be greatly improved in the low-collisionality ITER

  19. Diverse Expected Gradient Active Learning for Relative Attributes.

    Science.gov (United States)

    You, Xinge; Wang, Ruxin; Tao, Dacheng

    2014-06-02

    The use of relative attributes for semantic understanding of images and videos is a promising way to improve communication between humans and machines. However, it is extremely labor- and time-consuming to define multiple attributes for each instance in large amount of data. One option is to incorporate active learning, so that the informative samples can be actively discovered and then labeled. However, most existing active-learning methods select samples one at a time (serial mode), and may therefore lose efficiency when learning multiple attributes. In this paper, we propose a batch-mode active-learning method, called Diverse Expected Gradient Active Learning (DEGAL). This method integrates an informativeness analysis and a diversity analysis to form a diverse batch of queries. Specifically, the informativeness analysis employs the expected pairwise gradient length as a measure of informativeness, while the diversity analysis forces a constraint on the proposed diverse gradient angle. Since simultaneous optimization of these two parts is intractable, we utilize a two-step procedure to obtain the diverse batch of queries. A heuristic method is also introduced to suppress imbalanced multi-class distributions. Empirical evaluations of three different databases demonstrate the effectiveness and efficiency of the proposed approach.

  20. Improved safety and reduction in stent thrombosis associated with biodegradable polymer-based biolimus-eluting stents versus durable polymer-based sirolimus-eluting stents in patients with coronary artery disease: final 5-year report of the LEADERS (Limus Eluted From A Durable Versus ERodable Stent Coating) randomized, noninferiority trial.

    Science.gov (United States)

    Serruys, Patrick W; Farooq, Vasim; Kalesan, Bindu; de Vries, Ton; Buszman, Pawel; Linke, Axel; Ischinger, Thomas; Klauss, Volker; Eberli, Franz; Wijns, William; Morice, Marie Claude; Di Mario, Carlo; Corti, Roberto; Antoni, Diethmar; Sohn, Hae Y; Eerdmans, Pedro; Rademaker-Havinga, Tessa; van Es, Gerrit-Anne; Meier, Bernhard; Jüni, Peter; Windecker, Stephan

    2013-08-01

    This study sought to report the final 5 years follow-up of the landmark LEADERS (Limus Eluted From A Durable Versus ERodable Stent Coating) trial. The LEADERS trial is the first randomized study to evaluate biodegradable polymer-based drug-eluting stents (DES) against durable polymer DES. The LEADERS trial was a 10-center, assessor-blind, noninferiority, "all-comers" trial (N = 1,707). All patients were centrally randomized to treatment with either biodegradable polymer biolimus-eluting stents (BES) (n = 857) or durable polymer sirolimus-eluting stents (SES) (n = 850). The primary endpoint was a composite of cardiac death, myocardial infarction (MI), or clinically indicated target vessel revascularization within 9 months. Secondary endpoints included extending the primary endpoint to 5 years and stent thrombosis (ST) (Academic Research Consortium definition). Analysis was by intention to treat. At 5 years, the BES was noninferior to SES for the primary endpoint (186 [22.3%] vs. 216 [26.1%], rate ratio [RR]: 0.83 [95% confidence interval (CI): 0.68 to 1.02], p for noninferiority 1 year) and associated composite clinical outcomes. (Limus Eluted From A Durable Versus ERodable Stent Coating [LEADERS] trial; NCT00389220). Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  1. Selenium speciation and isotope composition in 77Se-enriched yeast using gradient elution HPLC separation and ICP-dynamic reaction cell-MS

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Sloth, Jens Jørgen; Hansen, M.

    2003-01-01

    using the enriched Se-77-selenite as substrate, were released by enzymatic hydrolysis using (I), a beta-glucosidase followed by a protease mixture, and (II), a commercial protease preparation. For selenium speciation the chromatographic selectivity of the cation exchange HPLC system was adjusted...

  2. Multivariate analysis of elution parameters for RP-HPLC with charged aerosol detection of sucrose caprate regioisomers

    DEFF Research Database (Denmark)

    Lie, Aleksander; Pedersen, Lars Haastrup

    2012-01-01

    and Environmental Engineering, Aalborg University, Denmark Sugar fatty acid monoesters have been shown to possess antibiotic and insecticidal properties. The physical and chemical properties of sugar fatty acid esters depend on the saccharide moiety, fatty acid chain length, and both position and degree...... for sucrose caprate regioisomers. As a sensitive method based on mass detection, charged aerosol detection was used. The investigation was conducted using design-of-experiments (DOE) methodology for development and prediction of elution strategies. The elution profiles were described by a number of important......BIOCAT2012, Hamburg University of Technology Book of Abstracts, p290 ISBN 987-3-941492 L73) Multivariate analysis of elution parameters for RP-HPLC with charged aerosol detection of sucrose caprate regioisomers Aleksander Lie and Lars Haastrup Pedersen Department of Biotechnology, Chemistry...

  3. Type D personality predicts chronic anxiety following percutaneous coronary intervention in the drug-eluting stent era

    DEFF Research Database (Denmark)

    Spindler, Helle; Pedersen, Susanne S.; Serruys, Patrick W.

    2007-01-01

      Background: Anxiety is an often overlooked risk factor in coronary artery disease (CAD). Hence, little is known about predictors of unremitting chronic anxiety in CAD patients. This study examined whether the distressed personality (Type D) predicts chronic anxiety post percutaneous coronary...... months post-PCI. Results: Of 167 patients anxious at 6 months, 108 (65%) were still anxious 12 months post-PCI. Significant univariable predictors of chronic anxiety were Type D personality (OR:3.17: 95% CI:1.64-6.14) and sirolimus-eluting stents (OR:0.51; 95% CI:0.27-0.98), with sirolimus-eluting stents...... showing a protective effect. In multivariable analyses, Type D personality (OR:3.31; 95% CI:1.59-6.87) and sirolimus-eluting stents (OR:0.44; 95% CI:0.21-0.92) remained significant independent predictors of chronic anxiety adjusting for depressive symptoms at 6 months, and demographic and clinical risk...

  4. DNA elution from buccal cells stored on Whatman FTA Classic Cards using a modified methanol fixation method.

    Science.gov (United States)

    Johanson, Helene C; Hyland, Valentine; Wicking, Carol; Sturm, Richard A

    2009-04-01

    We describe here a method for DNA elution from buccal cells and whole blood both collected onto Whatman FTA technology, using methanol fixation followed by an elution PCR program. Extracted DNA is comparable in quality to published Whatman FTA protocols, as judged by PCR-based genotyping. Elution of DNA from the dried sample is a known rate-limiting step in the published Whatman FTA protocol; this method enables the use of each 3-mm punch of sample for several PCR reactions instead of the standard, one PCR reaction per sample punch. This optimized protocol therefore extends the usefulness and cost effectiveness of each buccal swab sample collected, when used for nucleic acid PCR and genotyping.

  5. Computational Strain Gradient Crystal Plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2011-01-01

    A model for strain gradient crystal visco-plasticity is formulated along the lines proposed by Fleck andWillis (2009) for isotropic plasticity. Size-effects are included in the model due to the addition of gradient terms in both the free energy as well as through a dissipation potential. A finite...... element solution method is presented, which delivers the slip-rate field and the velocity-field based on two minimum principles. Some plane deformation problems relevant for certain specific orientations of a face centered cubic crystal under plane loading conditions are studied, and effective in......-plane parameters are developed based on the crystallographic properties of the material. The problem of cyclic shear of a single crystal between rigid platens is studied as well as void growth of a cylindrical void....

  6. Computational strain gradient crystal plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2014-01-01

    A numerical method for viscous strain gradient crystal plasticity theory is presented, which incorporates both energetic and dissipative gradient effects. The underlying minimum principles are discussed as well as convergence properties of the proposed finite element procedure. Three problems...... of plane crystal plasticity are studied: pure shear of a single crystal between rigid platens as well as plastic deformation around cylindrical voids in hexagonal close packed and face centered cubic crystals. Effective in-plane constitutive slip parameters for plane strain deformation of specifically...... oriented face centered cubic crystals are developed in terms of the crystallographic slip parameters. The effect on geometrically necessary dislocation structures introduced by plastic deformation is investigated as a function of the ratio of void radius to plasticity length scale....

  7. Vertebrate pressure-gradient receivers

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, Jakob

    2011-01-01

    The eardrums of all terrestrial vertebrates (tetrapods) are connected through Eustachian tubes or interaural canals. In some of the animals, these connections create pressure-gradient directionality, an enhanced directionality by interaction of sound arriving at both sides of the eardrum and stro......The eardrums of all terrestrial vertebrates (tetrapods) are connected through Eustachian tubes or interaural canals. In some of the animals, these connections create pressure-gradient directionality, an enhanced directionality by interaction of sound arriving at both sides of the eardrum....... Recent vertebrates form a continuum from perfect interaural transmission (0 dB in a certain frequency band) and pronounced eardrum directionality (30-40 dB) in the lizards, over somewhat attenuated transmission and limited directionality in birds and frogs, to the strongly attenuated interaural...

  8. Primordial vorticity and gradient expansion

    CERN Document Server

    Giovannini, Massimo

    2012-01-01

    The evolution equations of the vorticities of the electrons, ions and photons in a pre-decoupling plasma are derived, in a fully inhomogeneous geometry, by combining the general relativistic gradient expansion and the drift approximation within the Adler-Misner-Deser decomposition. The vorticity transfer between the different species is discussed in this novel framework and a set of general conservation laws, connecting the vorticities of the three-component plasma with the magnetic field intensity, is derived. After demonstrating that a source of large-scale vorticity resides in the spatial gradients of the geometry and of the electromagnetic sources, the total vorticity is estimated to lowest order in the spatial gradients and by enforcing the validity of the momentum constraint. By acknowledging the current bounds on the tensor to scalar ratio in the (minimal) tensor extension of the $\\Lambda$CDM paradigm the maximal comoving magnetic field induced by the total vorticity turns out to be, at most, of the or...

  9. Efficacy and Safety of Drug-Eluting Stents in the Real World: 8-Year Follow-Up

    Energy Technology Data Exchange (ETDEWEB)

    Pellegrini, Denise Oliveira, E-mail: dennizmo@yahoo.com.br; Gomes, Vitor Osório; Lasevitch, Ricardo; Smidt, Luis; Azeredo, Marco Aurélio; Ledur, Priscila; Bodanese, Rodrigo; Sinnott, Leonardo; Moriguchi, Emílio; Caramori, Paulo [Hospital São Lucas PUC, Porto Alegre, RS (Brazil)

    2014-09-15

    Drug-eluting stents have been used in daily practice since 2002, with the clear advantages of reducing the risk of target vessel revascularization and an impressive reduction in restenosis rate by 50%-70%. However, the occurrence of a late thrombosis can compromise long-term results, particularly if the risks of this event were sustained. In this context, a registry of clinical cases gains special value. To evaluate the efficacy and safety of drug-eluting stents in the real world. We report on the clinical findings and 8-year follow-up parameters of all patients that underwent percutaneous coronary intervention with a drug-eluting stent from January 2002 to April 2007. Drug-eluting stents were used in accordance with the clinical and interventional cardiologist decision and availability of the stent. A total of 611 patients were included, and clinical follow-up of up to 8 years was obtained for 96.2% of the patients. Total mortality was 8.7% and nonfatal infarctions occurred in 4.3% of the cases. Target vessel revascularization occurred in 12.4% of the cases, and target lesion revascularization occurred in 8% of the cases. The rate of stent thrombosis was 2.1%. There were no new episodes of stent thrombosis after the fifth year of follow-up. Comparative subanalysis showed no outcome differences between the different types of stents used, including Cypher®, Taxus®, and Endeavor®. These findings indicate that drug-eluting stents remain safe and effective at very long-term follow-up. Patients in the 'real world' may benefit from drug-eluting stenting with excellent, long-term results.

  10. High frequency single mode traveling wave structure for particle acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Ivanyan, M.I.; Danielyan, V.A.; Grigoryan, B.A.; Grigoryan, A.H. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Tsakanian, A.V. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Technische Universität Darmstadt, Institut TEMF, 64289 Darmstadt (Germany); Tsakanov, V.M., E-mail: tsakanov@asls.candle.am [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia); Vardanyan, A.S.; Zakaryan, S.V. [CANDLE Synchrotron Research Institute, 0040 Yerevan (Armenia)

    2016-09-01

    The development of the new high frequency slow traveling wave structures is one of the promising directions in accomplishment of charged particles high acceleration gradient. The disc and dielectric loaded structures are the most known structures with slowly propagating modes. In this paper a large aperture high frequency metallic two-layer accelerating structure is studied. The electrodynamical properties of the slowly propagating TM{sub 01} mode in a metallic tube with internally coated low conductive thin layer are examined.

  11. Adding functionality with additive manufacturing: Fabrication of titanium-based antibiotic eluting implants

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Sophie C. [School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Jamshidi, Parastoo [School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Eisenstein, Neil M. [School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Royal Centre for Defence Medicine, Birmingham Research Park, Vincent Drive, Edgbaston B15 2SQ (United Kingdom); Webber, Mark A. [School of Biosciences, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Hassanin, Hany [School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT (United Kingdom); School of Mechanical and Automotive Engineering, Kingston University, London SW15 3DW (United Kingdom); Attallah, Moataz M. [School of Materials and Metallurgy, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Shepherd, Duncan E.T. [Department of Mechanical Engineering, School of Engineering, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Addison, Owen [School of Dentistry, University of Birmingham, Edgbaston B15 2TT (United Kingdom); Grover, Liam M. [School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT (United Kingdom)

    2016-07-01

    Additive manufacturing technologies have been utilised in healthcare to create patient-specific implants. This study demonstrates the potential to add new implant functionality by further exploiting the design flexibility of these technologies. Selective laser melting was used to manufacture titanium-based (Ti-6Al-4V) implants containing a reservoir. Pore channels, connecting the implant surface to the reservoir, were incorporated to facilitate antibiotic delivery. An injectable brushite, calcium phosphate cement, was formulated as a carrier vehicle for gentamicin. Incorporation of the antibiotic significantly (p = 0.01) improved the compressive strength (5.8 ± 0.7 MPa) of the cement compared to non-antibiotic samples. The controlled release of gentamicin sulphate from the calcium phosphate cement injected into the implant reservoir was demonstrated in short term elution studies using ultraviolet-visible spectroscopy. Orientation of the implant pore channels were shown, using micro-computed tomography, to impact design reproducibility and the back-pressure generated during cement injection which ultimately altered porosity. The amount of antibiotic released from all implant designs over a 6 hour period (< 28% of the total amount) were found to exceed the minimum inhibitory concentrations of Staphylococcus aureus (16 μg/mL) and Staphylococcus epidermidis (1 μg/mL); two bacterial species commonly associated with periprosthetic infections. Antibacterial efficacy was confirmed against both bacterial cultures using an agar diffusion assay. Interestingly, pore channel orientation was shown to influence the directionality of inhibition zones. Promisingly, this work demonstrates the potential to additively manufacture a titanium-based antibiotic eluting implant, which is an attractive alternative to current treatment strategies of periprosthetic infections. - Highlights: • Titanium implants were additively manufactured with surface connected reservoirs. • Implants

  12. Safety and efficacy of everolimus-eluting stents for bare-metal in-stent restenosis

    Energy Technology Data Exchange (ETDEWEB)

    Ota, Hideaki [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Mahmoudi, Michael [University of Surrey, Guildford Road, Surrey, GU2-7XH (United Kingdom); Torguson, Rebecca; Satler, Lowell F.; Suddath, William O.; Pichard, Augusto D. [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States); Waksman, Ron, E-mail: ron.waksman@medstar.net [Division of Interventional Cardiology, MedStar Washington Hospital Center, Washington, DC 20010 (United States)

    2015-04-15

    Objective: The aim of this study was to compare the safety and efficacy of the everolimus-eluting stents (EES) with the paclitaxel-eluting stent (PES) and sirolimus-eluting stent (SES) for the treatment of bare-metal in-stent restenosis. Background: The optimal treatment for bare-metal in-stent restenosis remains controversial. Methods: The study cohort comprised 322 consecutive patients (543 lesions) who presented with bare-metal in-stent restenosis to our institution and underwent coronary artery stent implantation with EES (114 patients; 181 lesions), PES (65 patients; 116 lesions) and SES (143 patients; 246 lesions). The analyzed clinical parameters were the 1-year rates of death, Q-wave myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR), definite stent thrombosis (ST) and major adverse cardiac events (MACE) defined as the composite of death, MI, or TLR at 1-year. Results: The three groups were well matched for the conventional risk factors except for age and chronic kidney disease. The 1-year analyzed clinical parameters were similar in the three groups: death (EES = 3.5%, PES = 4.6%, SES = 4.2%; p = 0.94), MI (EES = 3.5%, PES = 6.3%, SES = 2.1%; p = 0.31), TLR (EES = 9.8%, PES = 9.5%, SES = 5.7%; p = 0.42), TVR (EES = 14.3%, PES = 11.1%, SES = 11.3%; p = 0.74), definite ST (EES = 0.9%, PES = 3.1%, SES = 3.5%; p = 0.38) and MACE (EES = 14.0%, PES = 15.4%, SES = 10.5%; p = 0.54). Male gender (hazard ratio = 0.47; 95% confidence interval = 0.25–0.88) and number of treated lesions (hazard ratio = 1.47; 95% confidence interval = 1.06–2.05) were found to be independent predictors of MACE. Conclusion: The results of the present study indicate that EES may provide similar safety and efficacy as first generation DES for the treatment of patients presenting with bare-metal in-stent restenosis.

  13. Gradient computation for VTI acoustic wavefield tomography

    KAUST Repository

    Li, Vladimir; Wang, Hui; Tsvankin, Ilya; Diaz, Esteban; Alkhalifah, Tariq Ali

    2016-01-01

    -power objective functions. We also obtain the gradient expressions for the data-domain objective function, which can incorporate borehole information necessary for stable VTI velocity analysis. These gradients are compared to the ones obtained with a space

  14. The H-mode of ASDEX

    International Nuclear Information System (INIS)

    1989-01-01

    The paper is a review of investigations of the H-mode on ASDEX performed since its discovery in 1982. The topics discussed are: (1) the development of the plasma profiles, with steep gradients in the edge region and flat profiles in the bulk plasma, (2) the MHD properties resulting from the profile changes, including an extensive stability analysis, (3) the impurity development, with special emphasis on the MHD aspects and on neoclassical impurity transport effects in quiescent H-phases, and (4) the properties of the edge plasma, including the evidence of three-dimensional distortions at the edge. The part on confinement includes scaling studies and the results of transport analysis. The power threshold of the H-mode is found to depend weakly on the density, but there is probably no dependence on the toroidal field or the current. For the operational range of the H-mode, new results for the limiter H-mode on ASDEX and the development of the H-mode under beam current drive conditions are included. A number of experiments are described which demonstrate the crucial role of the edge electron temperature in the L-H transition. New results of magnetic and density fluctuation studies at the plasma edge within the edge transport barrier are presented. Finally, the findings on ASDEX are compared with results obtained on other machines and are used to test various H-mode theories. (author). 131 refs, 103 figs, 1 tab

  15. Geometrical effects in X-mode scattering

    International Nuclear Information System (INIS)

    Bretz, N.

    1986-10-01

    One technique to extend microwave scattering as a probe of long wavelength density fluctuations in magnetically confined plasmas is to consider the launching and scattering of extraordinary (X-mode) waves nearly perpendicular to the field. When the incident frequency is less than the electron cyclotron frequency, this mode can penetrate beyond the ordinary mode cutoff at the plasma frequency and avoid significant distortions from density gradients typical of tokamak plasmas. In the more familiar case, where the incident and scattered waves are ordinary, the scattering is isotropic perpendicular to the field. However, because the X-mode polarization depends on the frequency ratios and the ray angle to the magnetic field, the coupling between the incident and scattered waves is complicated. This geometrical form factor must be unfolded from the observed scattering in order to interpret the scattering due to density fluctuations alone. The geometrical factor is calculated here for the special case of scattering perpendicular to the magnetic field. For frequencies above the ordinary mode cutoff the scattering is relatively isotropic, while below cutoff there are minima in the forward and backward directions which go to zero at approximately half the ordinary mode cutoff density

  16. Energetic particle effects on global MHD modes

    International Nuclear Information System (INIS)

    Cheng, C.Z.

    1990-01-01

    The effects of energetic particles on MHD type modes are studied by analytical theories and the nonvariational kinetic-MHD stability code (NOVA-K). In particular we address the problems of (1) the stabilization of ideal MHD internal kink modes and the excitation of resonant ''fishbone'' internal modes and (2) the alpha particle destabilization of toroidicity-induced Alfven eigenmodes (TAE) via transit resonances. Analytical theories are presented to help explain the NOVA-K results. For energetic trapped particles generated by neutral-beam injection (NBI) or ion cyclotron resonant heating (ICRH), a stability window for the n=1 internal kink mode in the hot particle beat space exists even in the absence of core ion finite Larmor radius effect (finite ω *i ). On the other hand, the trapped alpha particles are found to resonantly excite instability of the n=1 internal mode and can lower the critical beta threshold. The circulating alpha particles can strongly destabilize TAE modes via inverse Landau damping associated with the spatial gradient of the alpha particle pressure. 23 refs., 5 figs

  17. Interaction of tearing modes

    International Nuclear Information System (INIS)

    Satya, Y.; Schmidt, G.

    1979-01-01

    A fully developed tearing mode modifies the magnetic field profile. The effect of this profile modification on the linear growth rate of a different tearing mode in a slab and cylindrical geometry is investigated

  18. Instabilities in power law gradient hardening materials

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo

    2005-01-01

    Tension and compression instabilities are investigated for specimens with dimensions in the micron range. A finite strain generalization of a higher order strain gradient plasticity theory is implemented in a finite element scheme capable of modeling power law hardening materials. Effects...... of gradient hardening are found to delay the onset of localization under plane strain tension, and significantly reduce strain gradients in the localized zone. For plane strain compression gradient hardening is found to increase the load-carrying capacity significantly....

  19. Gravitational Resonance Spectroscopy with an Oscillating Magnetic Field Gradient in the GRANIT Flow through Arrangement

    International Nuclear Information System (INIS)

    Rebreyend, D.; Pignol, G.; Baeßler, S.; Nesvizhevsky, V. V.; Protasov, K.; Voronin, A.

    2014-01-01

    Gravitational resonance spectroscopy consists in measuring the energy spectrum of bouncing ultracold neutrons above a mirror by inducing resonant transitions between different discrete quantum levels. We discuss how to induce the resonances with a flow through arrangement in the GRANIT spectrometer, excited by an oscillating magnetic field gradient. The spectroscopy could be realized in two distinct modes (so called DC and AC) using the same device to produce the magnetic excitation. We present calculations demonstrating the feasibility of the newly proposed AC mode

  20. Emission characteristics of laser and superluminescent diodes with a gradient-index waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Bazarov, A.E.; Garmash, I.A.; Goldobin, I.S.; Eliukhin, V.A.; Pak, G.T.

    1987-05-01

    A study is made of the emission characteristics of laser and superluminescent diodes with gradient-index waveguides based on Al(x)Ga(1-x)As solid solutions, operating in the CW mode at room temperature. The coupling coefficients for a single-mode fiber are 25 and 18 percent for laser and superluminescent diodes, respectively, when an interface device consisting of three microlenses is used. 6 references.

  1. An education gradient in health, a health gradient in education, or a confounded gradient in both?

    Science.gov (United States)

    Lynch, Jamie L; von Hippel, Paul T

    2016-04-01

    There is a positive gradient associating educational attainment with health, yet the explanation for this gradient is not clear. Does higher education improve health (causation)? Do the healthy become highly educated (selection)? Or do good health and high educational attainment both result from advantages established early in the life course (confounding)? This study evaluates these competing explanations by tracking changes in educational attainment and Self-rated Health (SRH) from age 15 to age 31 in the National Longitudinal Study of Youth, 1997 cohort. Ordinal logistic regression confirms that high-SRH adolescents are more likely to become highly educated. This is partly because adolescent SRH is associated with early advantages including adolescents' academic performance, college plans, and family background (confounding); however, net of these confounders adolescent SRH still predicts adult educational attainment (selection). Fixed-effects longitudinal regression shows that educational attainment has little causal effect on SRH at age 31. Completion of a high school diploma or associate's degree has no effect on SRH, while completion of a bachelor's or graduate degree have effects that, though significant, are quite small (less than 0.1 points on a 5-point scale). While it is possible that educational attainment would have greater effect on health at older ages, at age 31 what we see is a health gradient in education, shaped primarily by selection and confounding rather than by a causal effect of education on health. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Strain gradient effects in surface roughening

    DEFF Research Database (Denmark)

    Borg, Ulrik; Fleck, N.A.

    2007-01-01

    evidence for strain gradient effects. Numerical analyses of a bicrystal undergoing in-plane tensile deformation are also studied using a strain gradient crystal plasticity theory and also by using a strain gradient plasticity theory for an isotropic solid. Both theories include an internal material length...

  3. Gradient remediability in linear distributed parabolic systems ...

    African Journals Online (AJOL)

    The aim of this paper is the introduction of a new concept that concerned the analysis of a large class of distributed parabolic systems. It is the general concept of gradient remediability. More precisely, we study with respect to the gradient observation, the existence of an input operator (gradient efficient actuators) ensuring ...

  4. Stent thrombosis with drug-eluting and bare-metal stents: evidence from a comprehensive network meta-analysis.

    Science.gov (United States)

    Palmerini, Tullio; Biondi-Zoccai, Giuseppe; Della Riva, Diego; Stettler, Christoph; Sangiorgi, Diego; D'Ascenzo, Fabrizio; Kimura, Takeshi; Briguori, Carlo; Sabatè, Manel; Kim, Hyo-Soo; De Waha, Antoinette; Kedhi, Elvin; Smits, Pieter C; Kaiser, Christoph; Sardella, Gennaro; Marullo, Antonino; Kirtane, Ajay J; Leon, Martin B; Stone, Gregg W

    2012-04-14

    The relative safety of drug-eluting stents and bare-metal stents, especially with respect to stent thrombosis, continues to be debated. In view of the overall low frequency of stent thrombosis, large sample sizes are needed to accurately estimate treatment differences between stents. We compared the risk of thrombosis between bare-metal and drug-eluting stents. For this network meta-analysis, randomised controlled trials comparing different drug-eluting stents or drug-eluting with bare-metal stents currently approved in the USA were identified through Medline, Embase, Cochrane databases, and proceedings of international meetings. Information about study design, inclusion and exclusion criteria, sample characteristics, and clinical outcomes was extracted. 49 trials including 50,844 patients randomly assigned to treatment groups were analysed. 1-year definite stent thrombosis was significantly lower with cobalt-chromium everolimus eluting stents (CoCr-EES) than with bare-metal stents (odds ratio [OR] 0·23, 95% CI 0·13-0·41). The significant difference in stent thrombosis between CoCr-EES and bare-metal stents was evident as early as 30 days (OR 0·21, 95% CI 0·11-0·42) and was also significant between 31 days and 1 year (OR 0·27, 95% CI 0·08-0·74). CoCr-EES were also associated with significantly lower rates of 1-year definite stent thrombosis compared with paclitaxel-eluting stents (OR 0·28, 95% CI 0·16-0·48), permanent polymer-based sirolimus-eluting stents (OR 0·41, 95% CI 0·24-0·70), phosphorylcholine-based zotarolimus-eluting stents (OR 0·21, 95% CI 0·10-0·44), and Resolute zotarolimus-eluting stents (OR 0·14, 95% CI 0·03-0·47). At 2-year follow-up, CoCr-EES were still associated with significantly lower rates of definite stent thrombosis than were bare-metal (OR 0·35, 95% CI 0·17-0·69) and paclitaxel-eluting stents (OR 0·34, 95% CI 0·19-0·62). No other drug-eluting stent had lower definite thrombosis rates compared with bare

  5. Hydrogen sulfide production by sulfate-reducing bacteria utilizing additives eluted from plastic resins.

    Science.gov (United States)

    Tsuchida, Daisuke; Kajihara, Yusuke; Shimidzu, Nobuhiro; Hamamura, Kengo; Nagase, Makoto

    2011-06-01

    In the present study it was demonstrated that organic additives eluted from plastic resins could be utilized as substrates by sulfate-reducing bacteria. Two laboratory-scale experiments, a microcosm experiment and a leaching experiment, were conducted using polyvinyl chloride (PVC) as a model plastic resin. In the former experiment, the conversion of sulfate to sulfide was evident in microcosms that received plasticized PVC as the sole carbon source, but not in those that received PVC homopolymer. Additionally, dissolved organic carbon accumulated only in microcosms that received plasticized PVC, indicating that the dissolved organic carbon originated from additives. In the leaching experiment, phenol and bisphenol A were found in the leached solutions. These results suggest that the disposal of waste plastics in inert waste landfills may result in the production of H(2)S.

  6. Characterization of polypropylene–polyethylene blends by temperature rising elution and crystallization analysis fractionation

    Science.gov (United States)

    del Hierro, Pilar

    2010-01-01

    The introduction of single-site catalysts in the polyolefins industry opens new routes to design resins with improved performance through multicatalyst-multireactor processes. Physical combination of various polyolefin types in a secondary extrusion process is also a common practice to achieve new products with improved properties. The new resins have complex structures, especially in terms of composition distribution, and their characterization is not always an easy task. Techniques like temperature rising elution fractionation (TREF) or crystallization analysis fractionation (CRYSTAF) are currently used to characterize the composition distribution of these resins. It has been shown that certain combinations of polyolefins may result in equivocal results if only TREF or CRYSTAF is used separately for their characterization. PMID:20730530

  7. Irinotecan drug eluting beads used as a treatment of advanced intra hepatic cholangiocarcinoma

    Directory of Open Access Journals (Sweden)

    Jean Amede Roch

    2008-10-01

    Full Text Available

    This report describes a 74-year-old male with unresectable intrahepatic cholangiocarcinoma (ICC. However surgical procedure is the only curative treatment, it often seems to be ineffective because of the aggressive behaviour of the disease. The role of systemic chemotherapy in the ICC is undefined with a median survival between 6.43 to 12.17 months obtained by using the combination chemotherapy of gemcitabine with cisplatin. In the present case, we performed a targeted treatment using drug eluting beads (DEB with irinotecan (IRI administered as transarterial-chemoembolization (TACE. After one session, the tumour vascularity decreased significantly at the one month evaluation on computed tomography (CT scan of the liver.  This case report suggested that minimally invasive transcatheter DEB embolization could be a promising, safe and effective treatment for selective patients with unresectable ICC.

  8. Successful drug-eluting stent implantation in a male patient with dextrocardia: a case report

    Directory of Open Access Journals (Sweden)

    Long Wenjie

    2017-12-01

    Full Text Available Situs inversus with dextrocardia is a rare condition, with complete transposition of all the body organs, including the heart. Percutaneous coronary intervention (PCI in these patients is technically difficult because of the mirror image of organs. Here, we describe a 56-year-old man with coronary heart disease with known situs inversus with dextrocardia and coronary percutaneous intervention was performed for stenosis in the right coronary artery. A drug eluting stent was implanted at this site successfully. This case suggested that the interventional management of such patients follows the same general rules as for non-dextrocardia patients, but the manipulation of the catheter and projection position choices need to be taken into consideration to obtain optimal benefits for the patient.

  9. Arterial healing following primary PCI using the Absorb everolimus-eluting bioresorbable vascular scaffold (Absorb BVS) versus the durable polymer everolimus-eluting metallic stent (XIENCE) in patients with acute ST-elevation myocardial infarction

    DEFF Research Database (Denmark)

    Räber, Lorenz; Onuma, Yoshinobu; Brugaletta, Salvatore

    2015-01-01

    Aims: The Absorb bioresorbable vascular scaffold (Absorb BVS) provides similar clinical outcomes compared with a durable polymer-based everolimus-eluting metallic stent (EES) in stable coronary artery disease patients. ST-elevation myocardial infarction (STEMI) lesions have been associated with d...

  10. Patient-Centered Tablet Application for Improving Medication Adherence after a Drug-Eluting Stent.

    Science.gov (United States)

    Shah, Vicki; Dileep, Anandu; Dickens, Carolyn; Groo, Vicki; Welland, Betty; Field, Jerry; Baumann, Matthew; Flores, Jose D; Shroff, Adhir; Zhao, Zhongsheng; Yao, Yingwei; Wilkie, Diana J; Boyd, Andrew D

    2016-01-01

    This study's objective was to evaluate a patient-centered educational electronic tablet application, "My Interventional Drug-Eluting Stent Educational App" (MyIDEA) to see if there was an increase in patient knowledge about dual antiplatelet therapy (DAPT) and medication possession ratio (MPR) compared to treatment as usual. In a pilot project, 24 elderly (≥50 years old) research participants were recruited after a drug-eluting stent. Eleven were randomized to the control arm and 13 to the interventional arm. All the participants completed psychological and knowledge questionnaires. Adherence was assessed through MPR, which was calculated at 3 months for all participants who were scheduled for second and third follow-up visits. Relative to control, the interventional group had a 10% average increase in MPR. As compared to the interventional group, more patients in the control group had poor adherence (<80% MPR). The psychological data revealed a single imbalance in anxiety between the control and interventional groups. On average, interventional participants spent 21 min using MyIDEA. Consumer health informatics has enabled us to engage patients with their health data using novel methods. Consumer health technology needs to focus more on patient knowledge and engagement to improve long-term health. MyIDEA takes a unique approach in targeting DAPT from the onset. MyIDEA leverages patient-centered information with clinical care and the electronic health record highlighting the patients' role as a team member in their own health care. The patients think critically about adverse events and how to solve issues before leaving the hospital.

  11. Patient Centered Tablet Application for improving medication adherence after a Drug Eluting Stent

    Directory of Open Access Journals (Sweden)

    Vicki Shah

    2016-12-01

    Full Text Available Background/Aims: This study’s objective was to evaluate a patient-centered educational electronic tablet application, My Interventional Drug-Eluting Stent Educational App (MyIDEA to see if there was an increase in patient knowledge about dual antiplatelet therapy (DAPT and medication possession ratio (MPR compared to treatment as usual. Methods: In a pilot project, 24 elderly (≥50 years-old research participants were recruited after a Drug Eluting Stent. 11 were randomized to the control arm and 13 to the interventional arm. All participants completed psychological and knowledge questionnaires. Adherence was assessed through MPR, which was calculated at three months for all participants who were scheduled for a second and third follow-up visit.Results: Relative to control, the interventional group had a 10% average increase in MPR. As compared to the interventional group, more patients in the control group had poor adherence (<80% MPR. The psychological data revealed a single imbalance in anxiety between the control and interventional groups. On average interventional participants spent 21 minutes using MyIDEA. Discussion: Consumer health informatics has enabled us to engage patients with their health data using novel methods. Consumer health technology needs to focus more on patient knowledge and engagement to improve long term health. MyIDEA takes a unique approach in targeting DAPT from the onset.Conclusion: MyIDEA leverages patient centered information with clinical care and the electronic health record highlighting the patients’ role as a team member in their own healthcare. The patients think critically about adverse events and how to solve issues before leaving the hospital.

  12. The Role Of Inflammation In Stent Restenosis More Than 1 Year Afetr Drug Eluting Stent Implantation

    Directory of Open Access Journals (Sweden)

    Hasan Shemirani

    2011-09-01

    Full Text Available Background: In stent restenosis (ISR following endovascular interventions is the main limitation of their long-term success. Despite advances have been made during recent years to decrease restenosis, it remains a challenging clinical problem.The aim of this study was to evaluate the relationship between angiographic coronary in stent restenosis, inflammation after successful stent implantation. Methods: This study included 78 patients, 35year old and higher who underwent coronary angiography more than 1 year after drug-eluting stent (DES implantation because of symptoms suggestive ischemia. Patients were divided into ISR group (case and patent stent group (control according to angiography results. For all patients blood lipids and high sensitivity C-Reactive Protein (hsCRP were measured simultaneously. Results: Age, sex, hypertension, current smoking, and lipid profile other than High Density Lipoprotein (HDL-C of patients in the case and control groups were similar .However, HDL-C < 40mg/L was more prevalent with ISR (66.7% vs. 30.8%, p=0.002. The hsCRP level was 2.98±2.06 mg/L in the case group and 2.50±1.80 mg/L in the control group. There were no significant differences in mean hsCRP concentration between the two groups (p=0.14, however mean hsCRP level was significantly higher in men of case group than control group (3.35mg/L vs. 2.21mg/L, p<0.05. Conclusion: This study demonstrates that in men but not in women inflammation may be a predictor of in stent restenosis more than 1 year after drug eluting stent implantation. Also, high-density lipoprotein (HDL probably has protective effect against stent restenosis.

  13. DMSO inhibits human platelet activation through cyclooxygenase-1 inhibition. A novel agent for drug eluting stents?

    International Nuclear Information System (INIS)

    Asmis, Lars; Tanner, Felix C.; Sudano, Isabella; Luescher, Thomas F.; Camici, Giovanni G.

    2010-01-01

    Background: DMSO is routinely infused together with hematopoietic cells in patients undergoing myeloablative therapy and was recently found to inhibit smooth muscle cells proliferation and arterial thrombus formation in the mouse by preventing tissue factor (TF), a key activator of the coagulation cascade. This study was designed to investigate whether DMSO prevents platelet activation and thus, whether it may represent an interesting agent to be used on drug eluting stents. Methods and results: Human venous blood from healthy volunteers was collected in citrated tubes and platelet activation was studied by cone and platelet analyzer (CPA) and rapid-platelet-function-assay (RPFA). CPA analysis showed that DMSO-treated platelets exhibit a lower adherence in response to shear stress (-15.54 ± 0.9427%, n = 5, P < 0.0001 versus control). Additionally, aggregometry studies revealed that DMSO-treated, arachidonate-stimulated platelets had an increased lag phase (18.0% ± 4.031, n = 9, P = 0.0004 versus control) as well as a decreased maximal aggregation (-6.388 ± 2.212%, n = 6, P = 0.0162 versus control). Inhibitory action of DMSO could be rescued by exogenous thromboxane A2 and was mediated, at least in part, by COX-1 inhibition. Conclusions: Clinically relevant concentrations of DMSO impair platelet activation by a thromboxane A2-dependent, COX-1-mediated effect. This finding may be crucial for the previously reported anti-thrombotic property displayed by DMSO. Our findings support a role for DMSO as a novel drug to prevent not only proliferation, but also thrombotic complications of drug eluting stents.

  14. Chemoembolization (TACE) of Unresectable Intrahepatic Cholangiocarcinoma with Slow-Release Doxorubicin-Eluting Beads: Preliminary Results

    International Nuclear Information System (INIS)

    Aliberti, Camillo; Benea, Giorgio; Tilli, Massimo; Fiorentini, Giammaria

    2008-01-01

    The purpose of this study was to evaluate the safety and efficacy of TACE with microspheres preloaded with doxorubicin in unresectable intrahepatic cholangiocarcinoma (UCH). Twenty patients with UCH were observed; 9 refused, preferring other palliative care or chemotherapy, and 11 agreed to be treated with one or more cycles of DC beads loaded with doxorubicin (100-150 mg) in a TACE procedure between February 2006 and September 2007. A total of 29 individual TACE procedures were performed. Follow-up imaging was performed on all patients before, immediately after, and 4 weeks after each TACE procedure to evaluate the response and need for further treatment. Each patient received i.v hydration, antibiotics, and medications against nausea and pain before TACE. Survival rate was calculated using Kaplan-Meier survival curve. A response rate of 100% followed RECIST criteria was observed. Eight of eleven patients are alive, with a median survival of 13 months. TACE was well tolerated by all patients. One patient developed hepatic abscess requiring antibiotic therapy. No evidence of marrow toxicity has been reported. Only one of nine patients treated with chemotherapy or palliative care is alive (with a median survival of 7 months in this group of patients). In conclusion, we suggest that doxorubicin-eluting beads TACE is a feasible and effective treatment in patients with UCH. Survival seems to be clearly prolonged in the treated group with respect to the palliative group. We consider that doxorubicin-eluting beads TACE of 100-150 mg may be an appropriate palliative therapy for these patients. Further studies are warranted to confirm these interesting preliminary data.

  15. Cost effectiveness of drug eluting coronary artery stenting in a UK setting: cost-utility study.

    Science.gov (United States)

    Bagust, A; Grayson, A D; Palmer, N D; Perry, R A; Walley, T

    2006-01-01

    To assess the cost effectiveness of drug eluting stents (DES) compared with conventional stents for treatment of symptomatic coronary artery disease in the UK. Cost-utility analysis of audit based patient subgroups by means of a simple economic model. Tertiary care. 12 month audit data for 2884 patients receiving percutaneous coronary intervention with stenting at the Cardiothoracic Centre Liverpool between January 2000 and December 2002. Risk of repeat revascularisation within 12 months of index procedure and reduction in risk from use of DES. Economic modelling was used to estimate the cost-utility ratio and threshold price premium. Four factors were identified for patients undergoing elective surgery (n = 1951) and two for non-elective surgery (n = 933) to predict risk of repeat revascularisation within 12 months. Most patients fell within the subgroup with lowest risk (57% of the elective surgery group with 5.6% risk and 91% of the non-elective surgery group with 9.9% risk). Modelled cost-utility ratios were acceptable for only one group of high risk patients undergoing non-elective surgery (only one patient in audit data). Restricting the number of DES for each patient improved results marginally: 4% of stents could then be drug eluting on economic grounds. The threshold price premium justifying 90% substitution of conventional stents was estimated to be 112 pound sterling (212 USD, 162 pound sterling) (sirolimus stents) or 89 pound sterling (167 USD, 130 pound sterling) (paclitaxel stents). At current UK prices, DES are not cost effective compared with conventional stents except for a small minority of patients. Although the technology is clearly effective, general substitution is not justified unless the price premium falls substantially.

  16. Scaling studies of the H-mode pedestal

    International Nuclear Information System (INIS)

    Groebner, R.J.; Osborne, T.H.

    1998-01-01

    The structure and scaling of the H-mode pedestal are examined for discharges in the DIII-D tokamak. For typical conditions, the pedestal values of the ion and electron temperatures T i and T e are comparable. Measurements of main ion and C 6+ profiles indicate that the ion pressure gradient in the barrier is 50%--100% of the electron pressure gradient for deuterium plasmas. The magnitude of the pressure gradient in the barrier often exceeds the predictions of infinite-n ballooning mode theory by a factor of two. Moreover, via the bootstrap current, the finite pressure gradient acts to entirely remove ballooning stability limits for typical discharges. For a large dataset, the width of the pressure barrier δ is best described by the dimensionless scaling δ/R ∝ (β pol ped ) 0.4 where (β pol ped ) is the pedestal value of poloidal beta and R is the major radius. Scalings based on the poloidal ion gyroradius or the edge density gradient do not adequately describe overall trends in the data set and the propagation of the pressure barrier observed between edge-localized modes. The width of the T i barrier is quite variable and is not a good measure of the width of the pressure barrier

  17. Temperature-gradient instability induced by conducting end walls

    International Nuclear Information System (INIS)

    Berk, H.L.; Ryutov, D.D.; Tsidulko, Yu.A.

    1990-04-01

    A new rapidly growing electron temperature gradient instability is found for a plasma in contact with a conducting wall. The linear instability analysis is presented and speculations are given for its nonlinear consequences. This instability illustrates that conducting walls can produce effects that are detrimental to plasma confinement. This mode should be of importance in open-ended systems including astrophysical plasmas, mirror machines and at the edge of tokamaks where field lines are open and are connected to limiters or divertors. 16 refs., 2 figs

  18. A short TE gradient-echo sequence using asymmetric sampling

    International Nuclear Information System (INIS)

    Fujita, Norihiko; Harada, Kohshi; Sakurai, Kosuke; Nakanishi, Katsuyuki; Kim, Shyogen; Kozuka, Takahiro

    1990-01-01

    We have developed a gradient-echo pulse sequence with a short TE less than 4 msec using a data set of asymmetric off-center sampling with a broad bandwidth. The use of such a short TE significantly reduces T 2 * dephasing effect even in a two-dimensional mode, and by collecting an off-center echo, motion-induced phase dispersion is also considerably decreased. High immunity of this sequence to these dephasing effects permits clear visualization of anatomical details near the skull base where large local field inhomogeneities and rapid blood flow such as in the internal carotid artery are present. (author)

  19. Conjugate gradient heat bath for ill-conditioned actions.

    Science.gov (United States)

    Ceriotti, Michele; Bussi, Giovanni; Parrinello, Michele

    2007-08-01

    We present a method for performing sampling from a Boltzmann distribution of an ill-conditioned quadratic action. This method is based on heat-bath thermalization along a set of conjugate directions, generated via a conjugate-gradient procedure. The resulting scheme outperforms local updates for matrices with very high condition number, since it avoids the slowing down of modes with lower eigenvalue, and has some advantages over the global heat-bath approach, compared to which it is more stable and allows for more freedom in devising case-specific optimizations.

  20. Stabilization of electron-scale turbulence by electron density gradient in national spherical torus experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Ruiz, J.; White, A. E. [MIT-Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Ren, Y.; Guttenfelder, W.; Kaye, S. M.; Leblanc, B. P.; Mazzucato, E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Lee, K. C. [National Fusion Research Institute, Daejeon (Korea, Republic of); Domier, C. W. [University of California at Davis, Davis, California 95616 (United States); Smith, D. R. [University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Yuh, H. [Nova Photonics, Inc., Princeton, New Jersey 08540 (United States)

    2015-12-15

    Theory and experiments have shown that electron temperature gradient (ETG) turbulence on the electron gyro-scale, k{sub ⊥}ρ{sub e} ≲ 1, can be responsible for anomalous electron thermal transport in NSTX. Electron scale (high-k) turbulence is diagnosed in NSTX with a high-k microwave scattering system [D. R. Smith et al., Rev. Sci. Instrum. 79, 123501 (2008)]. Here we report on stabilization effects of the electron density gradient on electron-scale density fluctuations in a set of neutral beam injection heated H-mode plasmas. We found that the absence of high-k density fluctuations from measurements is correlated with large equilibrium density gradient, which is shown to be consistent with linear stabilization of ETG modes due to the density gradient using the analytical ETG linear threshold in F. Jenko et al. [Phys. Plasmas 8, 4096 (2001)] and linear gyrokinetic simulations with GS2 [M. Kotschenreuther et al., Comput. Phys. Commun. 88, 128 (1995)]. We also found that the observed power of electron-scale turbulence (when it exists) is anti-correlated with the equilibrium density gradient, suggesting density gradient as a nonlinear stabilizing mechanism. Higher density gradients give rise to lower values of the plasma frame frequency, calculated based on the Doppler shift of the measured density fluctuations. Linear gyrokinetic simulations show that higher values of the electron density gradient reduce the value of the real frequency, in agreement with experimental observation. Nonlinear electron-scale gyrokinetic simulations show that high electron density gradient reduces electron heat flux and stiffness, and increases the ETG nonlinear threshold, consistent with experimental observations.

  1. Temperature Gradient in Hall Thrusters

    International Nuclear Information System (INIS)

    Staack, D.; Raitses, Y.; Fisch, N.J.

    2003-01-01

    Plasma potentials and electron temperatures were deduced from emissive and cold floating probe measurements in a 2 kW Hall thruster, operated in the discharge voltage range of 200-400 V. An almost linear dependence of the electron temperature on the plasma potential was observed in the acceleration region of the thruster both inside and outside the thruster. This result calls into question whether secondary electron emission from the ceramic channel walls plays a significant role in electron energy balance. The proportionality factor between the axial electron temperature gradient and the electric field is significantly smaller than might be expected by models employing Ohmic heating of electrons

  2. Generalized Gradient Approximation Made Simple

    International Nuclear Information System (INIS)

    Perdew, J.P.; Burke, K.; Ernzerhof, M.

    1996-01-01

    Generalized gradient approximations (GGA close-quote s) for the exchange-correlation energy improve upon the local spin density (LSD) description of atoms, molecules, and solids. We present a simple derivation of a simple GGA, in which all parameters (other than those in LSD) are fundamental constants. Only general features of the detailed construction underlying the Perdew-Wang 1991 (PW91) GGA are invoked. Improvements over PW91 include an accurate description of the linear response of the uniform electron gas, correct behavior under uniform scaling, and a smoother potential. copyright 1996 The American Physical Society

  3. Dai-Kou type conjugate gradient methods with a line search only using gradient.

    Science.gov (United States)

    Huang, Yuanyuan; Liu, Changhe

    2017-01-01

    In this paper, the Dai-Kou type conjugate gradient methods are developed to solve the optimality condition of an unconstrained optimization, they only utilize gradient information and have broader application scope. Under suitable conditions, the developed methods are globally convergent. Numerical tests and comparisons with the PRP+ conjugate gradient method only using gradient show that the methods are efficient.

  4. Streaming tearing mode

    Science.gov (United States)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  5. Vascular Response of the Segments Adjacent to the Proximal and Distal Edges of the ABSORB Everolimus-Eluting Bioresorbable Vascular Scaffold

    DEFF Research Database (Denmark)

    Gogas, Bill D; Serruys, Patrick W; Diletti, Roberto

    2012-01-01

    This study sought to investigate in vivo the vascular response at the proximal and distal edges of the second-generation ABSORB everolimus-eluting bioresorbable vascular scaffold (BVS).......This study sought to investigate in vivo the vascular response at the proximal and distal edges of the second-generation ABSORB everolimus-eluting bioresorbable vascular scaffold (BVS)....

  6. A randomized, controlled, multicenter trial to evaluate the safety and efficacy of Zotarolimus- vs. Paclitaxel-eluting stents in de novo occlusive lesions in coronary arteries

    DEFF Research Database (Denmark)

    Chevalier, Bernard; Dimario, Carlo; Neumann, Franz-Josef

    2013-01-01

    The ZOMAXX I trial tested the noninferiority of a zotarolimus-eluting coronary stent (ZoMaxx(™) ) when compared with a paclitaxel-eluting coronary stent (Taxus(™) Express(2™) ) in a randomized trial of percutaneous intervention for de novo coronary artery stenosis. Angiographic analysis at the pr...

  7. Local perivascular delivery of anti-restenotic agents from a drug-eluting poly(ε-caprolactone) stent cuff

    NARCIS (Netherlands)

    Pires, N.M.M.; Hoeven, B.L. van der; Vries, M.R. de; Havekes, L.M.; Vlijmen, B.J. van; Hennink, W.E.; Quax, P.H.A.; Jukema, J.W.

    2005-01-01

    The introduction of drug-eluting stents (DES) to prevent in-stent restenosis is one of the major advances in interventional cardiology. Currently many types of DES are under evaluation for effectiveness and safety, a time-consuming and difficult procedure in humans. An animal model that allows rapid

  8. Incidence of periprocedural myocardial infarction following stent implantation: Comparison between first- and second-generation drug-eluting stents

    NARCIS (Netherlands)

    Tandjung, Kenneth; Basalus, Mounir W.Z.; Muurman, Esther; Louwerenburg, Hans W.; van Houwelingen, Gert K.; Stoel, Martin G.; de Man, Frits H.A.F.; Jansen, Hanneke; Huisman, Jennifer; Linssen, Gerard C.M.; Droste, Herman T.; Nienhuis, Mark B.; von Birgelen, Clemens

    2012-01-01

    Background: First- and second-generation drug-eluting stents (DES) differ in coating materials, which may influence the incidence of periprocedural myocardial infarction (PMI). Objective: To compare the incidence of PMI between first- and second-generation DES, using the current Academic Research

  9. The study of drug eluting biodegradable intravascular stent with antiproliferation agent-paclitaxel in preventing vascular restenosis

    International Nuclear Information System (INIS)

    Xiao Yueyong; Zhang Jinshan; Cui Fuzhai; Meng Bo

    2004-01-01

    Objective: To define the effect of drug eluting BIS with antiproliferation agent-paclitaxel in preventing vascular restenosis. Methods: Bare BIS and drug BIS with 60 μg paclitaxel were prepared. Both types of the BIS were implanted into the infrarenal restenosis aortas in canine models, and the animals were euthanized 6 weeks after implantation for histopathological, morphometric and immunohistochemical assessment. Results: The mean lumen area of bare BIS group was (77 586.5 ± 66.0) μm 2 , and lumen of paclitaxel eluting BIS group was (113 435.9 ±71.0) μm 2 . The mean neointima area of bare BIS group was (24 803 ± 56) μm 2 , and paclitaxel eluting BIS group was (12 931 ± 63) μm 2 . The PCNA-positive ratio was (38 ± 15)% in bare BIS group and (11 ± 0.31)% in paclitaxel eluting BIS group. The statistically significant difference between the two groups were noted (P<0.01). Conclusion: BIS as a vehicle of loading and releasing drugs could significantly inhibit the VSMC and neointimal hyperplasia with antiproliferation agent-paclitaxel. BIS is a promising and new strategy in preventing the restenosis

  10. Determination of 99Mo contamination in 99mTc elute obtained from 99Mo/99mTc- generator

    International Nuclear Information System (INIS)

    Momennezhad, M.; Zakavi, S. R.; Sadeghi, R.

    2010-01-01

    99m Tc is a widely used radioisotope in nuclear medicine centers which is obtained by elution from Mo-99/Tc-99m generators. Usually the generators are either supplied by the Iran Atomic Energy Agency or by private companies from foreign countries. In this study we have measured 99 Mo contamination in 99m Tc elute from different generators in a period of one year. Materials and Methods: The radionuclide impurity of the 99m Tc elute were studied in two types of radionuclide generators (A: produced in Iran and B: Imported from other country). In-vitro measurements were performed using dose calibrator. Direct measurements were made, using a standard canister at the time of milking of the generators and also in Subsequent hours after milking. Results: The results showed a mean of 99 Mo impurity in generators A and B to be 0.00932±0.0043 and 0.0170±0.0127 respectively. Although the results showed that the 99 Mo contamination in 99 mTc elute was lesser than the maximum accepted activity limit of 0.015%, the difference in these two types may reflect different methods of productions of generator, as well as the quality control procedures. Conclusion: The mean of 99 Mo contamination in generators produced in Iran Atomic Energy Organization was lesser than generators imported from foreign origin.

  11. Response rates of hepatocellular carcinoma and hepatic colorectal cancer metastases to drug eluting bead regional liver therapy

    Institute of Scientific and Technical Information of China (English)

    Glenn W. Stambo; Deborah Cragan

    2017-01-01

    Aim: The purpose of this study was to evaluate and compare how hepatocellular carcinoma (HCC) and colorectal metastases respond to LC Bead chemoembolization using doxorubicin and irinotecan. Methods: The authors report their experience with doxorubicin and irinotecan eluting beads to treat 13 patients with primary HCC and 25 patients with colorectal metastases over a 1-year period at a single community based oncology practice. Within the colorectal cancer group they compared irinotecan eluting beads to doxorubicin eluting beads. Results:Nine of the 11 (81.8%) doxorubicin treated HCC patients had either complete response or partial response. All of the HCC lesions showed reduction in size and tumor enhancement and 10/11 (91%) HCC patients were alive at 24 months post treatment. Fisher's exact test revealed that among the 22 with colorectal metastases for whom follow-up data were available, those 11 who were treated with doxorubicin were significantly more likely to demonstrate complete or partial response compared to the 11 in the irinotecan treated group (P < 0.001). Conclusion:Overall, HCC and colon metastasis patients clearly demonstrated the effectiveness of drug eluting beads with 91% of the HCC patients alive 24 months after treatment.

  12. Natural history of optical coherence tomography-detected non-flow-limiting edge dissections following drug-eluting stent implantation

    DEFF Research Database (Denmark)

    Radu, Maria D; Räber, Lorenz; Heo, Jungho

    2014-01-01

    history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. METHODS...

  13. Cationic mobility in polystyrene sulfone exchangers - Application to the elution of a cation on an exchange column

    International Nuclear Information System (INIS)

    Menin, Jean-Pierre

    1969-01-01

    The aim of this work is to improve elutions and separations carried out on inorganic exchangers by selective electromigration of the ionic species to be displaced. To do this, it has been found indispensable to make a fundamental study of the mobility of cations in exchangers. As the field for this research we have chosen those organic exchangers whose structure and behaviour with respect to ion-exchange are much better known that in the case of their inorganic equivalents. We have related the idea of the equivalent conductivity to that of the cation mobility in the exchanger, and this has entailed determining the specific conductivity of the exchanger and the cation concentration in the resin. The results obtained have allowed us to draw up a hypothesis concerning the cation migration mechanism in the exchanger. The third part of our work has been the application of the preceding results to an operation on an ion-exchange column, viz. the elution by an acid solution of a single fixed ion, magnesium or strontium. This work has enabled us to show that the electromigration of a cation during its elution can markedly accelerate or retard this elution. (author) [fr

  14. Correlates and Impact of Coronary Artery Calcifications in Women Undergoing Percutaneous Coronary Intervention With Drug-Eluting Stents

    DEFF Research Database (Denmark)

    Giustino, Gennaro; Mastoris, Ioannis; Baber, Usman

    2016-01-01

    OBJECTIVES: The aim of this study was to investigate the clinical correlates and prognostic impact of coronary artery calcification (CAC) in women undergoing percutaneous coronary intervention with drug-eluting stents (DES). BACKGROUND: The clinical correlates and the prognostic significance of CAC...

  15. X-ray induced DNA double strand break production and repair in mammalian cells as measured by neutral filter elution

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, M O; Kohn, K W [National Institutes of Health, Bethesda, MD (USA)

    1979-10-01

    A neutral filter elution method was used for detecting DNA double strand breaks in mouse L1210 cells after X-ray. The assay detected the number of double strand breaks induced by as little as 1000 rad of X-ray. The rate of DNA elution through the filters under neutral conditions increased with X-ray dose. Certain conditions for deproteinization, pH, and filter type were shown to increase the assay's sensitivity. Hydrogen peroxide and Bleomycin also induced apparent DNA double strand breaks, although the ratios of double to single strand breaks varied from those produced by X-ray. The introduction of double strand cuts by HpA I restriction endonuclease in DNA lysed on filters resulted in a rapid rate of elution under neutral conditions, implying that the method can detect double strand breaks if they exist in the DNA. The eluted DNA banded with a double stranded DNA marker in cesium chloride. This evidence suggested that the assay detected DNA double strand breaks. L1210 cells were shown to rejoin most of the DNA double strand breaks induced by 5-10 krad of X-ray with a half-time of about 40 minutes. (author).

  16. Type D personality predicts death or myocardial infarction after bare metal stent or sirolimus-eluting stent implantation

    DEFF Research Database (Denmark)

    Pedersen, Susanne S.; Lemos, Pedro A; van Vooren, Priya R

    2004-01-01

    We investigated the effect of Type D personality on the occurrence of adverse events at nine months in patients with ischemic heart disease (IHD) after percutaneous coronary intervention (PCI) with sirolimus-eluting stents (SESs) or bare stents. Type D patients experience increased negative...

  17. A SINGLE-COLUMN PROCEDURE ON BOND ELUT CERTIFY FOR SYSTEMATIC TOXICOLOGICAL ANALYSIS OF DRUGS IN PLASMA AND URINE

    NARCIS (Netherlands)

    CHEN, XH; WIJSBEEK, J; FRANKE, JP; DEZEEUW, RA

    A single-column solid-phase extraction procedure was developed for the screening of acidic, neutral, and basic drugs from plasma. The recoveries of all 25 tested drugs exceeded 82%. After the plasma had been diluted with phosphate buffer (pH 6.0), the drugs were extracted using a single Bond Elut

  18. Ternary gradient metal-organic frameworks.

    Science.gov (United States)

    Liu, Chong; Rosi, Nathaniel L

    2017-09-08

    Gradient MOFs contain directional gradients of either structure or functionality. We have successfully prepared two ternary gradient MOFs based on bMOF-100 analogues, namely bMOF-100/102/106 and bMOF-110/100/102, via cascade ligand exchange reactions. The cubic unit cell parameter discrepancy within an individual ternary gradient MOF crystal is as large as ∼1 nm, demonstrating the impressive compatibility and flexibility of the component MOF materials. Because of the presence of a continuum of unit cells, the pore diameters within individual crystals also change in a gradient fashion from ∼2.5 nm to ∼3.0 nm for bMOF-100/102/106, and from ∼2.2 nm to ∼2.7 nm for bMOF-110/100/102, indicating significant porosity gradients. Like previously reported binary gradient MOFs, the composition of the ternary gradient MOFs can be easily controlled by adjusting the reaction conditions. Finally, X-ray diffraction and microspectrophotometry were used to analyse fractured gradient MOF crystals by comparing unit cell parameters and absorbance spectra at different locations, thus revealing the profile of heterogeneity (i.e. gradient distribution of properties) and further confirming the formation of ternary gradient MOFs.

  19. Strain gradient effects on cyclic plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Legarth, Brian Nyvang

    2010-01-01

    Size effects on the cyclic shear response are studied numerically using a recent higher order strain gradient visco-plasticity theory accounting for both dissipative and energetic gradient hardening. Numerical investigations of the response under cyclic pure shear and shear of a finite slab between...... rigid platens have been carried out, using the finite element method. It is shown for elastic–perfectly plastic solids how dissipative gradient effects lead to increased yield strength, whereas energetic gradient contributions lead to increased hardening as well as a Bauschinger effect. For linearly...... hardening materials it is quantified how dissipative and energetic gradient effects promote hardening above that of conventional predictions. Usually, increased hardening is attributed to energetic gradient effects, but here it is found that also dissipative gradient effects lead to additional hardening...

  20. A Simple and High-Throughput Analysis of Amatoxins and Phallotoxins in Human Plasma, Serum and Urine Using UPLC-MS/MS Combined with PRiME HLB μElution Platform

    Directory of Open Access Journals (Sweden)

    Shuo Zhang

    2016-05-01

    Full Text Available Amatoxins and phallotoxins are toxic cyclopeptides found in the genus Amanita and are among the predominant causes of fatal food poisoning in China. In the treatment of Amanita mushroom poisoning, an early and definite diagnosis is necessary for a successful outcome, which has prompted the development of protocols for the fast and confirmatory determination of amatoxins and phallotoxins in human biological fluids. For this purpose, a simple, rapid and sensitive multiresidue UPLC-MS/MS method for the simultaneous determination of α-amanitin, β-amanitin, γ-amanitin, phalloidin (PHD and phallacidin (PCD in human plasma, serum and urine was developed and validated. The diluted plasma, serum and urine samples were directly purified with a novel PRiME technique on a 96-well μElution plate platform, which allowed high-throughput sample processing and low reagent consumption. After purification, a UPLC-MS/MS analysis was performed using positive electrospray ionization (ESI+ in multiple reaction monitoring (MRM mode. This method fulfilled the requirements of a validation test, with good results for the limit of detection (LOD, lower limit of quantification (LLOQ, accuracy, intra- and inter-assay precision, recovery and matrix effects. All of the analytes were confirmed and quantified in authentic plasma, serum and urine samples obtained from cases of poisoning using this method. Using the PRiME μElution technique for quantification reduces labor and time costs and represents a suitable method for routine toxicological and clinical emergency analysis.

  1. A rapid and accurate approach for prediction of interactomes from co-elution data (PrInCE).

    Science.gov (United States)

    Stacey, R Greg; Skinnider, Michael A; Scott, Nichollas E; Foster, Leonard J

    2017-10-23

    An organism's protein interactome, or complete network of protein-protein interactions, defines the protein complexes that drive cellular processes. Techniques for studying protein complexes have traditionally applied targeted strategies such as yeast two-hybrid or affinity purification-mass spectrometry to assess protein interactions. However, given the vast number of protein complexes, more scalable methods are necessary to accelerate interaction discovery and to construct whole interactomes. We recently developed a complementary technique based on the use of protein correlation profiling (PCP) and stable isotope labeling in amino acids in cell culture (SILAC) to assess chromatographic co-elution as evidence of interacting proteins. Importantly, PCP-SILAC is also capable of measuring protein interactions simultaneously under multiple biological conditions, allowing the detection of treatment-specific changes to an interactome. Given the uniqueness and high dimensionality of co-elution data, new tools are needed to compare protein elution profiles, control false discovery rates, and construct an accurate interactome. Here we describe a freely available bioinformatics pipeline, PrInCE, for the analysis of co-elution data. PrInCE is a modular, open-source library that is computationally inexpensive, able to use label and label-free data, and capable of detecting tens of thousands of protein-protein interactions. Using a machine learning approach, PrInCE offers greatly reduced run time, more predicted interactions at the same stringency, prediction of protein complexes, and greater ease of use over previous bioinformatics tools for co-elution data. PrInCE is implemented in Matlab (version R2017a). Source code and standalone executable programs for Windows and Mac OSX are available at https://github.com/fosterlab/PrInCE , where usage instructions can be found. An example dataset and output are also provided for testing purposes. PrInCE is the first fast and easy

  2. High gradient RF breakdown study

    International Nuclear Information System (INIS)

    Laurent, L.; Luhmann, N.C. Jr.; Scheitrum, G.; Hanna, S.; Pearson, C.; Phillips, R.

    1998-01-01

    Stanford Linear Accelerator Center and UC Davis have been investigating high gradient RF breakdown and its effects on pulse shortening in high energy microwave devices. RF breakdown is a critical issue in the development of high power microwave sources and next generation linear accelerators since it limits the output power of microwave sources and the accelerating gradient of linacs. The motivation of this research is to find methods to increase the breakdown threshold level in X-band structures by reducing dark current. Emphasis is focused on improved materials, surface finish, and cleanliness. The test platform for this research is a traveling wave resonant ring. A 30 MW klystron is employed to provide up to 300 MW of traveling wave power in the ring to trigger breakdown in the cavity. Five TM 01 cavities have previously been tested, each with a different combination of surface polish and/or coating. The onset of breakdown was extended up to 250 MV/m with a TiN surface finish, as compared to 210 MV/m for uncoated OFE copper. Although the TiN coating was helpful in depressing the field emission, the lowest dark current was obtained with a 1 microinch surface finish, single-point diamond-turned cavity

  3. NIF optics phase gradient specfication

    International Nuclear Information System (INIS)

    Williams, W.; Auerbach, J.; Hunt, J.; Lawson, L.; Manes, K.; Orth, C.; Sacks, R.; Trenholme, J.; Wegner, P.

    1997-01-01

    A root-mean-square (rms) phase gradient specification seems to allow a good connection between the NIP optics quality and focal spot requirements. Measurements on Beamlet optics individually, and as a chain, indicate they meet the assumptions necessary to use this specification, and that they have a typical rms phase gradient of ∼80 angstrom/cm. This may be sufficient for NIP to meet the proposed Stockpile Stewardship Management Program (SSMP) requirements of 80% of a high- power beam within a 200-250 micron diameter spot. Uncertainties include, especially, the scale length of the optics phase noise, the ability of the adaptive optic to correct against pump-induced distortions and optics noise, and the possibility of finding mitigation techniques against whole-beam self-focusing (e.g. a pre- correction optic). Further work is needed in these areas to better determine the NIF specifications. This memo is a written summary of a presentation on this topic given by W. Williams 24 April 1997 to NIP and LS ampersand T personnel

  4. Ballooning mode stability for self-consistent pressure and current profiles at the H-mode edge

    International Nuclear Information System (INIS)

    Miller, R.L.; Lin-Liu, Y.R.; Osborne, T.H.; Taylor, T.S.

    1997-11-01

    The edge pressure gradient (H-mode pedestal) for computed equilibria in which the current density profile is consistent with the bootstrap current may not be limited by the first regime ballooning limit. The transition to second stability is easier for: higher elongation, intermediate triangularity, larger ratio, pedestal at larger radius, narrower pedestal width, higher q 95 , and lower collisionality

  5. The adaptation rate of a quantitative trait in an environmental gradient

    NARCIS (Netherlands)

    Hermsen, R|info:eu-repo/dai/nl/315062312

    2016-01-01

    The spatial range of a species habitat is generally determined by the ability of the species to cope with biotic and abiotic variables that vary in space. Therefore, the species range is itself an evolvable property. Indeed, environmental gradients permit a mode of evolution in which range expansion

  6. Single-Mode VCSELs

    Science.gov (United States)

    Larsson, Anders; Gustavsson, Johan S.

    The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.

  7. Bioabsorbable polymer-coated sirolimus-eluting stent implantation preserves coronary vasomotion: A DESSOLVE II trial sub-study.

    Science.gov (United States)

    Rusinaru, Dan; Vrolix, Mathias; Verheye, Stefan; Chowdhary, Saqib; Schoors, Danny; Di Mario, Carlo; Desmet, Walter; Donohoe, Dennis J; Ormiston, John A; Knape, Charlene; Bezerra, Hiram; Lansky, Alexandra; Wijns, William

    2015-12-01

    We studied coronary vasomotion in patients treated with the Mistent(®) absorbable polymer sirolimus-eluting stent (APSES) and in patients implanted with the Endeavor(®) zotarolimus-eluting stent (ZES). First generation (1st-gen) drug-eluting stents (DES) induce persistent vasomotor dysfunction in the treated coronary artery. It is unknown whether and to what extent the implantation of an absorbable polymer DES impairs coronary vasomotion. This sub-study of the DESSOLVE II trial included 19 APSES Mistent(®) and 10 ZES Endeavor(®) patients. Incremental atrial pacing and quantitative coronary angiography were used to assess vasomotion proximal and distal to the stent and in a reference segment at 9 months after implantation. Percent changes in vessel diameter with pacing versus baseline were calculated and compared. Vasomotor response of the APSES group was also compared with changes observed in a historical group of 17 patients implanted with a 1st-gen sirolimus-eluting stent (SES). Normal vasomotion (vasodilatation) was preserved and of comparable magnitude in the APSES and in the ZES group both proximally (P = 0.34) and distally (P = 0.38) to the stent. This finding was not observed in the 1st-gen SES group showing marked pacing-induced vasoconstriction at both stent edges (P absorbable polymer sirolimus-eluting stent is associated with preserved coronary vasomotion, comparable to that observed after implantation of the Endeavor(®) ZES, and distinct from 1st-gen SES which induce coronary vasomotor dysfunction. © 2015 Wiley Periodicals, Inc.

  8. Multifunctional surfaces with biomimetic nanofibres and drug-eluting micro-patterns for infection control and bone tissue formation

    Directory of Open Access Journals (Sweden)

    XN Chen

    2012-09-01

    Full Text Available For long-term orthopaedic implants, the creation of a surface that is repulsive to bacteria while adhesive to tissue cells represents a promising strategy to control infection. To obtain such multifunctional surfaces, two possible approaches were explored to incorporate a model antibiotic, rifampicin (Rf, into the osteogenic polycaprolactone (PCL/chitosan (CHS biomimetic nanofibre meshes by (1 blending Rf into the electrospinning solutions and then electrospinning into nanofibres (i.e., Rf-incorporating fibres, or (2 depositing Rf-containing poly(D,L-lactic-co-glycolic acid (PLGA micro-patterns onto the PCL/chitosan nanofibre meshes via ink-jet printing (i.e., Rf-eluting micro-pattern/fibre. Rapid release of Rf from both meshes was measured even though a relatively slower release rate was obtained from the Rf-eluting micro-pattern ones. Antibacterial assay with Staphylococcus epidermidis showed that both mesh surfaces could effectively kill bacteria and prevent biofilm formation. However, only Rf-eluting micro-pattern meshes favoured the attachment, spreading and metabolic activity of preosteoblasts in the cell culture study. Furthermore, the Rf-eluting micro-pattern meshes could better support the osteogenic differentiation of preosteoblasts by up-regulating the gene expression of bone markers (type I collagen and alkaline phosphatase. Clearly, compared to Rf-incorporating nanofibre meshes, Rf-eluting micro-patterns could effectively prevent biofilm formation without sacrificing the osteogenic properties of PCL/chitosan nanofibre surfaces. This finding provides an innovative avenue to design multifunctional surfaces for enhancing bone tissue formation while controlling infection.

  9. Tearing modes in tokamaks with lower hybrid current drive

    International Nuclear Information System (INIS)

    Xu, X.Q.

    1990-08-01

    In this paper, the effect of current drive on the tearing modes in the semi-collisional regime is analyzed using the drift-kinetic equation. A collisional operator is developed to model electron parallel conductivity. For the pure tearing modes the linear and quasilinear growth rates in the Rutherford regimes have been found to have roughly the same forms with a modified resistivity as without current drive. One interesting result is the prediction of a new instability. This instability, driven by the current gradient inside the tearing mode layer, is possibly related to MHD behavior observed in these experiments. 9 refs

  10. Global structures of Alfven-ballooning modes in magnetospheric plasmas

    International Nuclear Information System (INIS)

    Vetoulis, G.; Chen, Liu.

    1994-03-01

    The authors show that a steep plasma pressure gradient can lead to radially localized Alfven modes, which are damped through coupling to filed line resonances. These have been called drift Alfven balloning modes (DABM) and are the prime candidates to explain Pc4-Pc5 geomagnetic pulsations observed during storms. A strong dependence of the damping rate on the azimuthal wave number m is established, as well as on the equilibrium profile. A minimum azimuthal mode number can be found for the DABM to be radially trapped. The authors find that higher m DABMs are better localized, which is consistent with high-m observations

  11. Fueling profile sensitivities of trapped particle mode transport to TNS

    International Nuclear Information System (INIS)

    Mense, A.T.; Attenberger, S.E.; Houlberg, W.A.

    1977-01-01

    A key factor in the plasma thermal behavior is the anticipated existence of dissipative trapped particle modes. A possible scheme for controlling the strength of these modes was found. The scheme involves varying the cold fueling profile. A one dimensional multifluid transport code was used to simulate plasma behavior. A multiregime model for particle and energy transport was incorporated based on pseudoclassical, trapped electron, and trapped ion regimes used elsewhere in simulation of large tokamaks. Fueling profiles peaked toward the plasma edge may provide a means for reducing density-gradient-driven trapped particle modes, thus reducing diffusion and conduction losses

  12. Collisional drift waves in the H-mode edge

    International Nuclear Information System (INIS)

    Sen, S.

    1994-01-01

    The stability of the collisional drift wave in a sheared slab geometry is found to be severely restricted at the H-mode edge plasma due to the very steep density gradient. However, a radially varying transverse velocity field is found to play the key role in stability. Velocity profiles usually found in the H-mode plasma stabilize drift waves. On the other hand, velocity profiles corresponding to the L-mode render collisional drift waves unstable even though the magnetic shear continues to play its stabilizing role. (author). 24 refs

  13. Determination of ximelagatran, melagatran and two intermediary metabolites in plasma by mixed-mode solid phase extraction and LC-MS/MS.

    Science.gov (United States)

    Dunér, Kristina; Bäckström, Jonas; Magnell, Niklas; Svennberg, Henrik; Ahnoff, Martin; Logren, Ulrika

    2007-06-01

    An analytical method was developed for the determination of ximelagatran, an oral direct thrombin inhibitor, its active metabolite melagatran, and the two intermediate metabolites, OH-melagatran and ethyl-melagatran in human plasma. Extraction of plasma was carried out on a mixed mode bonded sorbent material (C8/SO(3)(-)). All four analytes, including their isotope-labelled internal standards, were eluted at high ionic strength with a mixture of 50% methanol and 50% buffer (0.25 M ammonium acetate and 0.05 M formic acid, pH 5.3) with an extraction recovery above 80%. The extracts were demonstrated to be clean in terms of a low concentration of albumin and lysoPC. The sample extraction was fully automated and performed in 96-well plates using a Tecan Genesis pipetting robot. Analysis of the extracts were performed with liquid chromatography followed by positive electrospray ionization mass spectrometry. The low organic content and the low pH of the extracts allowed for, after dilution 1:3 with buffer, direct injection onto the LC-column. The four analytes were separated on a C18 analytical LC-column using gradient elution with the acetonitrile concentration varying from 10 to 30% (v/v) and the ammonium acetate and acetic acid concentration kept constant at 10 and 5 mmol/L, respectively, at a flow rate of 0.75 mL/min. Linearity was achieved over the calibrated range 0.010-4.0 micromol/L with accuracy and relative standard deviation in the range 96.9-101.2% and 6.6-17.1%, respectively at LLOQ, and in the range 94.7-102.6% and 2.7-6.8%, respectively at concentrations above 3 x LLOQ. The method replaces a manual method, and displays the advantages of having a fully automated sample clean-up, no evaporation/reconstitution step, high recovery, and complete LC-separation of all four analytes.

  14. Mechanisms of detonation formation due to a temperature gradient

    Science.gov (United States)

    Kapila, A. K.; Schwendeman, D. W.; Quirk, J. J.; Hawa, T.

    2002-12-01

    Emergence of a detonation in a homogeneous, exothermically reacting medium can be deemed to occur in two phases. The first phase processes the medium so as to create conditions ripe for the onset of detonation. The actual events leading up to preconditioning may vary from one experiment to the next, but typically, at the end of this stage the medium is hot and in a state of nonuniformity. The second phase consists of the actual formation of the detonation wave via chemico-gasdynamic interactions. This paper considers an idealized medium with simple, rate-sensitive kinetics for which the preconditioned state is modelled as one with an initially prescribed linear gradient of temperature. Accurate and well-resolved numerical computations are carrried out to determine the mode of detonation formation as a function of the size of the initial gradient. For shallow gradients, the result is a decelerating supersonic reaction wave, a weak detonation, whose trajectory is dictated by the initial temperature profile, with only weak intervention from hydrodynamics. If the domain is long enough, or the gradient less shallow, the wave slows down to the Chapman-Jouguet speed and undergoes a swift transition to the ZND structure. For sharp gradients, gasdynamic nonlinearity plays a much stronger role. Now the path to detonation is through an accelerating pulse that runs ahead of the reaction wave and rearranges the induction-time distribution there to one that bears little resemblance to that corresponding to the initial temperature gradient. The pulse amplifies and steepens, transforming itself into a complex consisting of a lead shock, an induction zone, and a following fast deflagration. As the pulse advances, its three constituent entities attain progressively higher levels of mutual coherence, to emerge as a ZND detonation. For initial gradients that are intermediate in size, aspects of both the extreme scenarios appear in the path to detonation. The novel aspect of this study

  15. Prediction of gradient retention data for hydrophilic interaction liquid chromatographic separation of native and fluorescently labeled oligosaccharides.

    Science.gov (United States)

    Vaňková, Nikola; Česla, Petr

    2017-02-17

    In this work, we have investigated the predictive properties of mixed-mode retention model and oligomeric mixed-mode model, taking into account the contribution of monomeric units to the retention, in hydrophilic interaction liquid chromatography. The gradient retention times of native maltooligosaccharides and their fluorescent derivatives were predicted in the oligomeric series with number of monomeric glucose units in the range from two to seven. The maltooligosaccharides were separated on a packed column with carbamoyl-bonded silica stationary phase and 15 gradient profiles with different initial and final mobile phase composition were used with the gradient times 5; 7.5 and 10min. The predicted gradient retention times were compared for calculations based on isocratic retention data and gradient retention data, which provided better accuracy of the results. By comparing two different mobile phase additives, the more accurate retention times were predicted in mobile phases containing ammonium acetate. The acidic derivatives, prepared by reaction of an oligosaccharide with 2-aminobenzoic acid or 8-aminonaphthalene-1,3,6-trisulfonic acid, provided more accurate predictions of the retention data in comparison to native oligosaccharides or their neutral derivatives. The oligomeric mixed-mode model allowed prediction of gradient retention times using only one gradient profile, which significantly speeded-up the method development. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Double-mode pulsation

    International Nuclear Information System (INIS)

    Cox, A.N.

    1982-01-01

    Double mode pulsation is a very pervasive phenomenon in stars all over the Hertzsprung-Russell diagram. In order of increasing radius, examples are: ZZ Ceti stars, the sun, the delta Scuti stars, RR Lyrae variables, the β Cephei variables and those related to them, Cepheids, and maybe even the Mira stars. These many modes have been interpreted as both radial and nonradial modes, but in many cases the actual mode has not been clearly identified. Yellow giants seem to be the most simple pulsators with a large majority of the RR Lyrae variables and Cepheids showing only one pulsation period. We limit this review to those very few cases for classical Cepheids and RR Lyrae variables which display two modes. For these we know many facts about these stars, but the actual cause of the pulsation in two modes simultaneously remains unknown

  17. Strength gradient enhances fatigue resistance of steels

    Science.gov (United States)

    Ma, Zhiwei; Liu, Jiabin; Wang, Gang; Wang, Hongtao; Wei, Yujie; Gao, Huajian

    2016-02-01

    Steels are heavily used in infrastructure and the transportation industry, and enhancing their fatigue resistance is a major challenge in materials engineering. In this study, by introducing a gradient microstructure into 304 austenitic steel, which is one of the most widely used types of stainless steel, we show that a strength gradient substantially enhances the fatigue life of the material. Pre-notched samples with negative strength gradients in front of the notch’s tip endure many more fatigue cycles than do samples with positive strength gradients during the crack initiation stage, and samples with either type of gradient perform better than do gradient-free samples with the same average yield strength. However, as a crack grows, samples with positive strength gradients exhibit better resistance to fatigue crack propagation than do samples with negative gradients or no gradient. This study demonstrates a simple and promising strategy for using gradient structures to enhance the fatigue resistance of materials and complements related studies of strength and ductility.

  18. The stability of weakly collisional plasmas with thermal and composition gradients

    DEFF Research Database (Denmark)

    Pessah, M.E.; Chakraborty, S.

    2013-01-01

    and magnitudes of the gradients in the temperature and the mean molecular weight, the plasma can be subject to a wide variety of unstable modes which include modifications to the magnetothermal instability (MTI), the heat-flux-driven buoyancy instability (HBI), and overstable gravity modes previously studied...... in homogeneous media. We also find that there are new modes which are driven by heat conduction and particle diffusion. We discuss the astrophysical implications of our findings for a representative galaxy cluster where helium has sedimented. Our findings suggest that the core insulation that results from...

  19. Streaming gravity mode instability

    International Nuclear Information System (INIS)

    Wang Shui.

    1989-05-01

    In this paper, we study the stability of a current sheet with a sheared flow in a gravitational field which is perpendicular to the magnetic field and plasma flow. This mixing mode caused by a combined role of the sheared flow and gravity is named the streaming gravity mode instability. The conditions of this mode instability are discussed for an ideal four-layer model in the incompressible limit. (author). 5 refs

  20. Local effect of equilibrium current on tearing mode stability

    International Nuclear Information System (INIS)

    Cozzani, F.

    1985-12-01

    The local effect of the equilibrium current on the linear stability of low poloidal number tearing modes in tokamaks is investigated analytically. The plasma response inside the tearing layer is derived from fluid theory and the local equilibrium current is shown to couple to the mode dynamics through its gradient, which is proportional to the local electron temperature gradient under the approximations used in the analysis. The relevant eigenmode equations, expressing Ampere's law and the plasma quasineutrality condition, respectively, are suitably combined in a single integral equation, from which a variational principle is formulated to derive the mode dispersion relations for several cases of interest. The local equilibrium current is treated as a small perturbation of the known results for the m greater than or equal to 2 and the m = 1 tearing modes in the collisional regime, and the m greater than or equal to 2 tearing mode in the semicollisional regime; its effect is found to enhance stabilization for the m greater than or equal to 2 drift-tearing mode in the collisional regime, whereas the m = 1 growth rate is very slightly increased and the stabilizing effect of the parallel thermal conduction on the m greater than or equal to 2 mode in the semicollisional regime is slightly reduced

  1. Strain gradient effects on steady state crack growth in rate-sensitive materials

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Niordson, Christian Frithiof; Hutchinson, John W.

    2012-01-01

    , a characteristic velocity, at which the toughness becomes independent of the rate-sensitivity, has been observed. It is the aim to bring forward a similar characteristic velocity for the current strain gradient visco-plastic model, as-well as to signify its use in future visco-plastic material modeling.......Steady state crack propagation produce substantial plastic strain gradients near the tip, which are accompanied by a high density of geometrically necessary dislocations and additional local strain hardening. Here, the objective is to study these gradient effects on Mode I toughness...... of a homogeneous rate-sensitive metal, using a higher order plasticity theory. Throughout, emphasis is on the toughness rate-sensitivity, as a recent numerical study of a conventional material (no gradient effects) has indicated a significant influence of both strain rate hardening and crack tip velocity. Moreover...

  2. A randomized multicenter comparison of hybrid sirolimus-eluting stents with bioresorbable polymer versus everolimus-eluting stents with durable polymer in total coronary occlusion: rationale and design of the Primary Stenting of Occluded Native Coronary Arteries IV study

    Directory of Open Access Journals (Sweden)

    Teeuwen Koen

    2012-12-01

    Full Text Available Abstract Background Percutaneous recanalization of total coronary occlusion (TCO was historically hampered by high rates of restenosis and reocclusions. The PRISON II trial demonstrated a significant restenosis reduction in patients treated with sirolimus-eluting stents compared with bare metal stents for TCO. Similar reductions in restenosis were observed with the second-generation zotarolimus-eluting stent and everolimus-eluting stent. Despite favorable anti-restenotic efficacy, safety concerns evolved after identifying an increased rate of very late stent thrombosis (VLST with drug-eluting stents (DES for the treatment of TCO. Late malapposition caused by hypersensitivity reactions and chronic inflammation was suggested as a probable cause of these VLST. New DES with bioresorbable polymer coatings were developed to address these safety concerns. No randomized trials have evaluated the efficacy and safety of the new-generation DES with bioresorbable polymers in patients treated for TCO. Methods/Design The prospective, randomized, single-blinded, multicenter, non-inferiority PRISON IV trial was designed to evaluate the safety, efficacy, and angiographic outcome of hybrid sirolimus-eluting stents with bioresorbable polymers (Orsiro; Biotronik, Berlin, Germany compared with everolimus-eluting stents with durable polymers (Xience Prime/Xpedition; Abbott Vascular, Santa Clara, CA, USA in patients with successfully recanalized TCOs. In total, 330 patients have been randomly allocated to each treatment arm. Patients are eligible with estimated duration of TCO ≥4 weeks with evidence of ischemia in the supply area of the TCO. The primary endpoint is in-segment late luminal loss at 9-month follow-up angiography. Secondary angiographic endpoints include in-stent late luminal loss, minimal luminal diameter, percentage of diameter stenosis, in-stent and in-segment binary restenosis and reocclusions at 9-month follow-up. Additionally, optical coherence

  3. Long-Term Results of Everolimus-Eluting Stents Versus Drug-Eluting Balloons in Patients With Bare-Metal In-Stent Restenosis: 3-Year Follow-Up of the RIBS V Clinical Trial.

    Science.gov (United States)

    Alfonso, Fernando; Pérez-Vizcayno, María José; García Del Blanco, Bruno; Otaegui, Imanol; Masotti, Mónica; Zueco, Javier; Veláquez, Maite; Sanchís, Juan; García-Touchard, Arturo; Lázaro-García, Rosa; Moreu, José; Bethencourt, Armando; Cuesta, Javier; Rivero, Fernando; Cárdenas, Alberto; Gonzalo, Nieves; Jiménez-Quevedo, Pilar; Fernández, Cristina

    2016-06-27

    The aim of this study was to compare the long-term efficacy of everolimus-eluting stents (EES) and drug-eluting balloons (DEB) in patients with bare-metal stent in-stent restenosis (ISR). The relative long-term clinical efficacy of current therapeutic modalities in patients with ISR remains unknown. The 3-year clinical follow-up (pre-specified endpoint) of patients included in the RIBS V (Restenosis Intra-Stent of Bare-Metal Stents: Drug-Eluting Balloon vs Everolimus-Eluting Stent Implantation) randomized clinical trial was analyzed. All patients were followed yearly using a pre-defined structured questionnaire. A total of 189 patients with bare-metal stent ISR were allocated to either EES (n = 94) or DEB (n = 95). Clinical follow-up at 1, 2, and 3 years was obtained in all patients (100%). Compared with patients treated with DEB, those treated with EES obtained better angiographic results, including larger minimal luminal diameter at follow-up (primary study endpoint; 2.36 ± 0.6 mm vs. 2.01 ± 0.6 mm; p 1 year) target vessel (3 [3.2%] vs. 3 [3.2%]; p = 0.95) and target lesion (1 [1%] vs. 2 [2.1%]; p = 0.54) revascularization was low and similar in the 2 arms. Rates of definite or probable stent thrombosis (1% vs. 0%) were also similar in the 2 arms. The 3-year clinical follow-up of the RIBS V clinical trial confirms the sustained safety and efficacy of EES and DEB in patients treated for bare-metal stent ISR. In this setting, EES reduce the need for target lesion revascularization at very long-term follow-up. (RIBS V [Restenosis Intra-Stent of Bare Metal Stents: Paclitaxel-Eluting Balloon vs Everolimus-Eluting Stent] [RIBS V]; NCT01239953). Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  4. Randomized Comparison of Ridaforolimus- and Zotarolimus-Eluting Coronary Stents in Patients With Coronary Artery Disease: Primary Results From the BIONICS Trial (BioNIR Ridaforolimus-Eluting Coronary Stent System in Coronary Stenosis).

    Science.gov (United States)

    Kandzari, David E; Smits, Pieter C; Love, Michael P; Ben-Yehuda, Ori; Banai, Shmuel; Robinson, Simon D; Jonas, Michael; Kornowski, Ran; Bagur, Rodrigo; Iniguez, Andres; Danenberg, Haim; Feldman, Robert; Jauhar, Rajiv; Chandna, Harish; Parikh, Manish; Perlman, Gidon Y; Balcells, Mercedes; Markham, Peter; Ozan, Melek Ozgu; Genereux, Philippe; Edelman, Elazer R; Leon, Martin B; Stone, Gregg W

    2017-10-03

    The safety and efficacy of a novel cobalt alloy-based coronary stent with a durable elastomeric polymer eluting the antiproliferative agent ridaforolimus for treatment of patients with coronary artery disease is undetermined. A prospective, international 1:1 randomized trial was conducted to evaluate in a noninferiority design the relative safety and efficacy of ridaforolimus-eluting stents (RESs) and slow-release zotarolimus-eluting stents among 1919 patients undergoing percutaneous coronary intervention at 76 centers. Inclusion criteria allowed enrollment of patients with recent myocardial infarction, total occlusions, bifurcations lesions, and other complex conditions. Baseline clinical and angiographic characteristics were similar between the groups. Overall, mean age was 63.4 years, 32.5% had diabetes mellitus, and 39.7% presented with acute coronary syndromes. At 12 months, the primary end point of target lesion failure (composite of cardiac death, target vessel-related myocardial infarction, and target lesion revascularization) was 5.4% for both devices (upper bound of 1-sided 95% confidence interval 1.8%, P noninferiority =0.001). Definite/probable stent thrombosis rates were low in both groups (0.4% RES versus 0.6% zotarolimus-eluting stent, P =0.75); 13-month angiographic in-stent late lumen loss was 0.22±0.41 mm and 0.23±0.39 mm ( P noninferiority =0.004) for the RES and zotarolimus-eluting stent groups, respectively, and intravascular ultrasound percent neointimal hyperplasia was 8.10±5.81 and 8.85±7.77, respectively ( P noninferiority =0.01). In the present trial, which allowed broad inclusion criteria, the novel RESs met the prespecified criteria for noninferiority compared with zotarolimus-eluting stents for the primary end point of target lesion failure at 12 months and had similar measures of late lumen loss. These findings support the safety and efficacy of RESs in patients who are representative of clinical practice. URL: http

  5. Dual-Mode Combustor

    Science.gov (United States)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  6. Antipastorialism : Resistant Georgic Mode

    National Research Council Canada - National Science Library

    Zimmerman, Donald

    2000-01-01

    .... Abolitionists, women, Afro-British slaves, and those who protested land enclosure developed a multivalent, resistant mode of writing, which I name 'antipastoralism', that countered orthodox, poetical...

  7. Nonlinear drift tearing mode

    International Nuclear Information System (INIS)

    Zelenyj, L.M.; Kuznetsova, M.M.

    1989-01-01

    Nonlinear study of magnetic perturbation development under single-mode conditions in collision-free plasma in configurations with the magnetic field shear is investigated. Results are obtained with regard of transverse component of electrical field and its effect on ion dynamics within wide range of ion Larmor radius value and values of magnetic field shear. Increments of nonlinear drift tearing mode are obtained and it is shown that excitation drastic conditions of even linearly stable modes are possible. Mechanism of instability nonlinear stabilization is considered and the value of magnetic island at the saturation threshold is estimeted. Energy of nonlinear drift tearing mode is discussed

  8. Ballooning stability analysis of JET H-mode discharges

    International Nuclear Information System (INIS)

    O'Brien, D.P.; Galvao, R.; Keilhacker, M.; Lazzaro, E.; Watkins, M.L.

    1989-01-01

    Previous studies of the stability of a large aspect ratio model equilibrium to ideal MHD ballooning modes have shown that across the bulk of the plasma there exist two marginally stable values of the pressure gradient parameter α. These define an unstable zone which separates the first (small α) stable region from the second (large α) stable region. Close to the separatrix, however, the first and second regions can coalesce when the surface averaged current density, Λ, exceeds a critical value. The plasma in this region is then stable to ballooning modes at all values of the pressure gradient. In this paper we extend these results to JET H-mode equilibria using a finite aspect ratio ballooning formalism, and assess the relevance of ideal ballooning stability in these discharges. In particular we analyse shot 15894 at time 56 sec. which is 1.3 s into the H-phase. (author) 4 refs., 4 figs

  9. Stability properties of cold blanket systems for current driven modes

    International Nuclear Information System (INIS)

    Ohlsson, D.

    1977-12-01

    The stability problem of the boundary regions of cold blanket systems with induced currents parallel to the lines of force is formulated. Particular interest is focused on two types of modes: first electrostatic modes driven by the combined effects of a transverse resistivity gradient due to a spatially non-uniform electron temperature and a longitudinal current, second electromagnetic kink like modes driven by the torque arising from a transverse current density gradient and magnetic field perturbations. It is found that the combination of various dissipative and neutral gas effects introduces strong stabilizing effects within specific parameter ranges. For particular steady-state models investigated it is shown that these effects become of importance in laboratory plasmas at relatively high densities, low temperatures and moderate magnetic field strengths. Stability diagrams based on specific steady-state cold plasma blanket models will be presented

  10. A general strategy for performing temperature-programming in high performance liquid chromatography--prediction of segmented temperature gradients.

    Science.gov (United States)

    Wiese, Steffen; Teutenberg, Thorsten; Schmidt, Torsten C

    2011-09-28

    In the present work it is shown that the linear elution strength (LES) model which was adapted from temperature-programming gas chromatography (GC) can also be employed to predict retention times for segmented-temperature gradients based on temperature-gradient input data in liquid chromatography (LC) with high accuracy. The LES model assumes that retention times for isothermal separations can be predicted based on two temperature gradients and is employed to calculate the retention factor of an analyte when changing the start temperature of the temperature gradient. In this study it was investigated whether this approach can also be employed in LC. It was shown that this approximation cannot be transferred to temperature-programmed LC where a temperature range from 60°C up to 180°C is investigated. Major relative errors up to 169.6% were observed for isothermal retention factor predictions. In order to predict retention times for temperature gradients with different start temperatures in LC, another relationship is required to describe the influence of temperature on retention. Therefore, retention times for isothermal separations based on isothermal input runs were predicted using a plot of the natural logarithm of the retention factor vs. the inverse temperature and a plot of the natural logarithm of the retention factor vs. temperature. It could be shown that a plot of lnk vs. T yields more reliable isothermal/isocratic retention time predictions than a plot of lnk vs. 1/T which is usually employed. Hence, in order to predict retention times for temperature-gradients with different start temperatures in LC, two temperature gradient and two isothermal measurements have been employed. In this case, retention times can be predicted with a maximal relative error of 5.5% (average relative error: 2.9%). In comparison, if the start temperature of the simulated temperature gradient is equal to the start temperature of the input data, only two temperature-gradient

  11. Brachytherapy Application With In Situ Dose Painting Administered by Gold Nanoparticle Eluters

    International Nuclear Information System (INIS)

    Sinha, Neeharika; Cifter, Gizem; Sajo, Erno; Kumar, Rajiv; Sridhar, Srinivas; Nguyen, Paul L.; Cormack, Robert A.; Makrigiorgos, G. Mike; Ngwa, Wilfred

    2015-01-01

    Purpose: Recent studies show promise that administering gold nanoparticles (GNP) to tumor cells during brachytherapy could significantly enhance radiation damage to the tumor. A new strategy proposed for sustained administration of the GNP in prostate tumors is to load them into routinely used brachytherapy spacers for customizable in situ release after implantation. This in silico study investigated the intratumor biodistribution and corresponding dose enhancement over time due to GNP released from such GNP-loaded brachytherapy spacers (GBS). Method and Materials: An experimentally determined intratumoral diffusion coefficient (D) for 10-nm nanoparticles was used to estimate D for other sizes by using the Stokes-Einstein equation. GNP concentration profiles, obtained using D, were then used to calculate the corresponding dose enhancement factor (DEF) for each tumor voxel, using dose painting-by-numbers approach, for times relevant to the considered brachytherapy sources' lifetimes. The investigation was carried out as a function of GNP size for the clinically applicable low-dose-rate brachytherapy sources iodine-125 (I-125), palladium-103 (Pd-103), and cesium-131 (Cs-131). Results: Results showed that dose enhancement to tumor voxels and subvolumes during brachytherapy can be customized by varying the size of GNP released or eluted from the GBS. For example, using a concentration of 7 mg/g GNP, significant DEF (>20%) could be achieved 5 mm from a GBS after 5, 12, 25, 46, 72, 120, and 195 days, respectively, for GNP sizes of 2, 5, 10, 20, 30, and 50 nm and for 80 nm when treating with I-125. Conclusions: Analyses showed that using Cs-131 provides the highest dose enhancement to tumor voxels. However, given its relatively longer half-life, I-125 presents the most flexibility for customizing the dose enhancement as a function of GNP size. These findings provide a useful reference for further work toward development of potential new brachytherapy application

  12. Brachytherapy Application With In Situ Dose Painting Administered by Gold Nanoparticle Eluters

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Neeharika [Department of Sciences, Wentworth Institute of Technology, Boston, Massachusetts (United States); Cifter, Gizem [Department of Physics and Applied Physics, University of Massachusetts, Lowell, Massachusetts (United States); Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital and Harvard Medical School, Boston, Massachusetts (United States); Sajo, Erno [Department of Physics and Applied Physics, University of Massachusetts, Lowell, Massachusetts (United States); Kumar, Rajiv; Sridhar, Srinivas [Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital and Harvard Medical School, Boston, Massachusetts (United States); Electronic Materials Research Institute and Department of Physics, Northeastern University, Boston, Massachusetts (United States); Nguyen, Paul L.; Cormack, Robert A.; Makrigiorgos, G. Mike [Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital and Harvard Medical School, Boston, Massachusetts (United States); Ngwa, Wilfred, E-mail: wngwa@lroc.harvard.edu [Department of Physics and Applied Physics, University of Massachusetts, Lowell, Massachusetts (United States); Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women' s Hospital and Harvard Medical School, Boston, Massachusetts (United States)

    2015-02-01

    Purpose: Recent studies show promise that administering gold nanoparticles (GNP) to tumor cells during brachytherapy could significantly enhance radiation damage to the tumor. A new strategy proposed for sustained administration of the GNP in prostate tumors is to load them into routinely used brachytherapy spacers for customizable in situ release after implantation. This in silico study investigated the intratumor biodistribution and corresponding dose enhancement over time due to GNP released from such GNP-loaded brachytherapy spacers (GBS). Method and Materials: An experimentally determined intratumoral diffusion coefficient (D) for 10-nm nanoparticles was used to estimate D for other sizes by using the Stokes-Einstein equation. GNP concentration profiles, obtained using D, were then used to calculate the corresponding dose enhancement factor (DEF) for each tumor voxel, using dose painting-by-numbers approach, for times relevant to the considered brachytherapy sources' lifetimes. The investigation was carried out as a function of GNP size for the clinically applicable low-dose-rate brachytherapy sources iodine-125 (I-125), palladium-103 (Pd-103), and cesium-131 (Cs-131). Results: Results showed that dose enhancement to tumor voxels and subvolumes during brachytherapy can be customized by varying the size of GNP released or eluted from the GBS. For example, using a concentration of 7 mg/g GNP, significant DEF (>20%) could be achieved 5 mm from a GBS after 5, 12, 25, 46, 72, 120, and 195 days, respectively, for GNP sizes of 2, 5, 10, 20, 30, and 50 nm and for 80 nm when treating with I-125. Conclusions: Analyses showed that using Cs-131 provides the highest dose enhancement to tumor voxels. However, given its relatively longer half-life, I-125 presents the most flexibility for customizing the dose enhancement as a function of GNP size. These findings provide a useful reference for further work toward development of potential new brachytherapy application

  13. Prototyping high-gradient mm-wave accelerating structures

    International Nuclear Information System (INIS)

    Nanni, Emilio A.; Dolgashev, Valery A.; Haase, Andrew; Neilson, Jeffrey; Tantawi, Sami

    2017-01-01

    We present single-cell accelerating structures designed for high-gradient testing at 110 GHz. The purpose of this work is to study the basic physics of ultrahigh vacuum RF breakdown in high-gradient RF accelerators. The accelerating structures are π-mode standing-wave cavities fed with a TM 01 circular waveguide. The structures are fabricated using precision milling out of two metal blocks, and the blocks are joined with diffusion bonding and brazing. The impact of fabrication and joining techniques on the cell geometry and RF performance will be discussed. First prototypes had a measured Q 0 of 2800, approaching the theoretical design value of 3300. The geometry of these accelerating structures are as close as practical to singlecell standing-wave X-band accelerating structures more than 40 of which were tested at SLAC. This wealth of X-band data will serve as a baseline for these 110 GHz tests. Furthermore, the structures will be powered with short pulses from a MW gyrotron oscillator. RF power of 1 MW may allow an accelerating gradient of 400 MeV/m to be reached.

  14. A gradient activation method for direct methanol fuel cells

    International Nuclear Information System (INIS)

    Liu, Guicheng; Yang, Zhaoyi; Halim, Martin; Li, Xinyang; Wang, Manxiang; Kim, Ji Young; Mei, Qiwen; Wang, Xindong; Lee, Joong Kee

    2017-01-01

    Highlights: • A gradient activation method was reported firstly for direct methanol fuel cells. • The activity recovery of Pt-based catalyst was introduced into the novel activation process. • The new activation method led to prominent enhancement of DMFC performance. • DMFC performance was improved with the novel activation step by step within 7.5 h. - Abstract: To realize gradient activation effect and recover catalytic activity of catalyst in a short time, a gradient activation method has firstly been proposed for enhancing discharge performance and perfecting activation mechanism of the direct methanol fuel cell (DMFC). This method includes four steps, i.e. proton activation, activity recovery activation, H_2-O_2 mode activation and forced discharging activation. The results prove that the proposed method has gradually realized replenishment of water and protons, recovery of catalytic activity of catalyst, establishment of transfer channels for electrons, protons, and oxygen, and optimization of anode catalyst layer for methanol transfer in turn. Along with the novel activation process going on, the DMFC discharge performance has been improved, step by step, to more than 1.9 times higher than that of the original one within 7.5 h. This method provides a practicable activation way for the real application of single DMFCs and stacks.

  15. Sensitivity of ITER MHD global stability to edge pressure gradients

    International Nuclear Information System (INIS)

    Hogan, J.T.; Martynov, A.

    1994-01-01

    In view of the preliminary nature of boundary models for reactor tokamaks, the sensitivity to edge gradients of the global mode MHD stability of the ITER EDA configuration has been examined. The POLAR-2D equilibrium and TORUS stability codes developed by the Keldysh Institute have been used. Transport-related profiles from the PRETOR transport code (developed by the ITER Joint Central Team) and axisymmetric equilibria for these profiles from the TEQ code (L.D. Pearlstein, LLNL) were taken as a starting point for the study. These baseline profiles are found to have quite high global stability limits, in the range g(Troyon) = 4-5. The major focus of this study is to examine global mode stability assuming small variations about the baseline profiles, changing the pressure gradients near the boundary. Such changes can be expected with an improved boundary model. Reduced stability limits are found in such cases, and unstable cases with g = 2-3 are found. Thus, the assumption of ITER stability limits higher than g = 2 must be treated with caution

  16. Experimental studies of tearing mode and resistive wall mode dynamics in the reversed field pinch configuration

    International Nuclear Information System (INIS)

    Malmberg, Jenny-Ann

    2003-06-01

    It is relatively straightforward to establish equilibrium in magnetically confined plasmas, but the plasma is frequently susceptible to a variety of instabilities that are driven by the free energy in the magnetic field or in the pressure gradient. These unstable modes exhibit effects that affect the particle, momentum and heat confinement properties of the configuration. Studies of the dynamics of several of the most important modes are the subject of this thesis. The studies are carried out on plasmas in the reversed field pinch (RFP) configuration. One phenomenon commonly observed in RFPs is mode wall locking. The localized nature of these phase- and wall locked structures results in localized power loads on the wall which are detrimental for confinement. A detailed study of the wall locked mode phenomenon is performed based on magnetic measurements from three RFP devices. The two possible mechanisms for wall locking are investigated. Locking as a result of tearing modes interacting with a static field error and locking due to the presence of a non-ideal boundary. The characteristics of the wall locked mode are qualitatively similar in a device with a conducting shell system (TPE-RX) compared to a device with a resistive shell (Extrap T2). A theoretical model is used for evaluating the threshold values for wall locking due to eddy currents in the vacuum vessel in these devices. A good correlation with experiment is observed for the conducting shell device. The possibility of successfully sustaining discharges in a resistive shell RFP is introduced in the recently rebuilt device Extrap T2R. Fast spontaneous mode rotation is observed, resulting in low magnetic fluctuations, low loop voltage and improved confinement. Wall locking is rarely observed. The low tearing mode amplitudes allow for the theoretically predicted internal non-resonant on-axis resistive wall modes to be observed. These modes have not previously been distinguished due to the formation of wall

  17. Saturation mechanism of decaying ion temperature gradient driven turbulence with kinetic electrons

    International Nuclear Information System (INIS)

    Idomura, Yasuhiro

    2016-01-01

    We present full-f gyrokinetic simulations of the ion temperature gradient driven (ITG) turbulence including kinetic electrons. By comparing decaying ITG turbulence simulations with adiabatic and kinetic electron models, an impact of kinetic electrons on the ITG turbulence is investigated. It is found that significant electron transport occurs even in the ITG turbulence, and both ion and electron temperature profiles are relaxed. In steady states, both cases show upshifts of nonlinear critical ion temperature gradients from linear ones, while their saturation mechanisms are qualitatively different. In the adiabatic electron case, the ITG mode is stabilized by turbulence driven zonal flows. On the other hand, in the kinetic electron case, passing electrons transport shows fine resonant structures at mode rational surfaces, which generate corrugated density profiles. Such corrugated density profiles lead to fine radial electric fields following the neoclassical force balance relation. The resulting E × B shearing rate greatly exceeds the linear growth rate of the ITG mode. (author)

  18. The Effect of Plasma Shape on H-Mode Pedestal Characteristics on DIII-D

    International Nuclear Information System (INIS)

    T.H. Osborne; J.R. Ferron; R.J. Groebner; L.L. Lao; A.W. Leonard; R. Maingi; R.L. Miller; A.D. Turnbull; M.R. Wade; J.G. Watkins

    1999-01-01

    The characteristics of the H-mode are studied in discharges with varying triangularity and squareness. The pressure at the top of the H-mode pedestal increases strongly with triangularity primarily due to an increase in the margin by which the edge pressure gradient exceeds the ideal ballooning mode first stability limit. Two models are considered for how the edge may exceed the ballooning mode limit. In one model [1], access to the ballooning mode second stable regime allows the edge pressure gradient and associated bootstrap current to continue to increase until an edge localized, low toroidal mode number, ideal kink mode is destabilized. In the second model [2], the finite width of the H-mode transport barrier, and diamagnetic effects raise the pressure gradient limit above the ballooning mode limit. We observe a weak inverse dependence of the width of the H-mode transport barrier, Δ, on triangularity relative to the previously obtained [3] scaling Δ ∞ (β P PED ) 1/2 . The energy loss for Type I ELMs increases with triangularity in proportion to the pedestal energy increase. The temperature profile is found to respond stiffly to changes in T PED at low temperature, while at high temperature the response is additive. The response of the density profile is also found to play a role in the response of the total stored energy to changes in the W PED

  19. External kink (peeling) modes in x-point geometry

    International Nuclear Information System (INIS)

    Huysmans, G T A

    2005-01-01

    The influence of the separatrix on the stability of edge current driven external kink (peeling) modes has been studied. Two approaches have been compared: taking the limit towards the separatrix using linear ideal and resistive MHD stability codes and including the complete x-point geometry using a new resistive MHD code. A strong stabilizing effect has been observed for the ideal and the resistive peeling mode for instabilities driven by the edge current gradient. Both approaches are in good agreement. A new resistive instability remains unstable and is not significantly affected by the separatrix. This mode is a combination of a kink and a tearing type mode and could be called a peeling-tearing mode

  20. Thermal conduction down steep temperature gradients

    International Nuclear Information System (INIS)

    Bell, A.R.; Evans, R.G.; Nicholas, D.J.

    1980-08-01

    The Fokker-Planck equation has been solved numerically in one spatial and two velocity dimensions in order to study thermal conduction in large temperature gradients. An initially cold plasma is heated at one end of the spatial grid producing temperature gradients with scale lengths of a few times the electron mean free path. The heat flow is an order of magnitude smaller than that predicted by the classical theory which is valid in the limit of small temperature gradients. (author)