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Sample records for plasma study applications

  1. Plasma Applications

    NASA Astrophysics Data System (ADS)

    Kristiansen, M.; Guenther, A. H.

    Plasmas have numerous applications for civilian as well as defense purposes. However, technical development is still in its infancy. Many new important applications depend only upon the imagination of engineers and scientists. In contrast to other develping technologies, applications from the fields of plasma science and engineering can only evolve through a multidisciplinary synergism. Research in plasma chemistry and physics together with gaseous electronics, fluid dynamics and thermodynamics, particularly mass and heat transfer, must be coupled with electro-chemistry and material science research particularly those aspects dealing with surfaces. In this paper we attempt to evaluate the importance of plasma applications. Obviously, it is impossible to do justice to all the important areas. The selection of topics is, therefore, influenced by the authors' interests and background. We will outline most of the applications rather briefly and concentrate in some detail on those areas in which we are interested.

  2. Studying surface glow discharge for application in plasma aerodynamics

    NASA Astrophysics Data System (ADS)

    Tereshonok, D. V.

    2014-02-01

    Surface glow discharge in nitrogen between two infinite planar electrodes occurring on the same plane has been studied in the framework of a diffusion-drift model. Based on the results of numerical simulations, the plasma structure of this discharge is analyzed and the possibility of using it in plasma aerodynamics is considered.

  3. Application of nonlinear methods to the study of ionospheric plasma

    NASA Astrophysics Data System (ADS)

    Chernyshov, A. A.; Mogilevsky, M. M.; Kozelov, B. V.

    2015-01-01

    Most of the processes taking place in the auroral region of Earth's ionosphere are reflected in a variety of dynamic forms of the aurora borealis. In order to study these processes it is necessary to consider temporary and spatial variations of the characteristics of ionospheric plasma. Most traditional methods of classical physics are applicable mainly for stationary or quasi-stationary phenomena, but dynamic regimes, transients, fluctuations, selfsimilar scaling could be considered using the methods of nonlinear dynamics. Special interest is the development of the methods for describing the spatial structure and the temporal dynamics of auroral ionosphere based on the ideas of percolation theory and fractal geometry. The fractal characteristics (the Hausdorff fractal dimension and the index of connectivity) of Hall and Pedersen conductivities are used to the description of fractal patterns in the ionosphere. To obtain the self-consistent estimates of the parameters the Hausdorff fractal dimension and the index of connectivity in the auroral zone, an additional relation describing universal behavior of the fractal geometry of percolation at the critical threshold is applied. Also, it is shown that Tsallis statistics can be used to study auroral ionosphere

  4. Plasma Assisted Combustion: Fundamental Studies and Engine Applications

    NASA Astrophysics Data System (ADS)

    Lefkowitz, Joseph K.

    Successful and efficient ignition in short residence time environments or ultra-lean mixtures is a key technological challenge for the evolution of advanced combustion devices in terms of both performance and efficiency. To meet this challenge, interest in plasma assisted combustion (PAC) has expanded over the past 20 years. However, understanding of the underlying physical processes of ignition by plasma discharge remains elementary. In order to shed light on the key processes involved, two main thrusts of research were undertaken in this dissertation. First, demonstration of the applicability of plasma discharges in engines and engine-like environments was carried out using a microwave discharge and a nanosecond repetitively pulsed discharge in an internal combustion engine and a pulsed detonation engine, respectively. Major conclusions include the extension of lean ignition limits for both engines, significant reduction of ignition time for mixtures with large minimum ignition energy, and the discovery of the inter-pulse coupling effect of nanosecond repetitively pulsed (NRP) discharges at high frequency. In order to understand the kinetic processes that led to these improvements, the second thrust of research directly explored the chemical kinetic processes of plasma discharges with hydrocarbon fuels. For this purpose, a low pressure flow reactor with a NRP dielectric barrier discharge cell was assembled. The discharge cell was fitted with a Herriott type multipass mirror arrangement, which allowed quantitative laser absorption spectroscopy to be performed in situ during the plasma discharge. Experiments on methane and ethylene mixtures with oxygen, argon, and helium revealed the importance of low temperature oxidation pathways in PAC. In particular, oxygen addition reactions were shown to be of primary importance in the oxidation of these small hydrocarbons in the temperature range of 300-600 K. Kinetic modeling tools, including both a coupled plasma and

  5. Study of Pulsed vs. RF Plasma Properties for Surface Processing Applications

    NASA Astrophysics Data System (ADS)

    Tang, Ricky; Hopkins, Matthew; Barnat, Edward; Miller, Paul

    2015-09-01

    The ability to manipulate the plasma parameters (density, E/N) was previously demonstrated using a double-pulsed column discharge. Experiments extending this to large-surface plasmas of interest to the plasma processing community were conducted. Differences between an audio-frequency pulsed plasma and a radio-frequency (rf) discharge, both prevalent in plasma processing applications, were studied. Optical emission spectroscopy shows higher-intensity emission in the UV/visible range for the pulsed plasma comparing to the rf plasma at comparable powers. Data suggest that the electron energy is higher for the pulsed plasma leading to higher ionization, resulting in increased ion density and ion flux. Diode laser absorption measurements of the concentration of the 1S5 metastable and 1S4 resonance states of argon (correlated with the plasma E/N) provide comparisons between the excitation/ionization states of the two plasmas. Preliminary modeling efforts suggest that the low-frequency polarity switch causes a much more abrupt potential variation to support interesting transport phenomena, generating a ``wave'' of higher temperature electrons leading to more ionization, as well as ``sheath capture'' of a higher density bolus of ions that are then accelerated during polarity switch.

  6. Study of electron current extraction from a radio frequency plasma cathode designed as a neutralizer for ion source applications

    NASA Astrophysics Data System (ADS)

    Jahanbakhsh, Sina; Satir, Mert; Celik, Murat

    2016-02-01

    Plasma cathodes are insert free devices that are developed to be employed as electron sources in electric propulsion and ion source applications as practical alternatives to more commonly used hollow cathodes. Inductively coupled plasma cathodes, or Radio Frequency (RF) plasma cathodes, are introduced in recent years. Because of its compact geometry, and simple and efficient plasma generation, RF plasma source is considered to be suitable for plasma cathode applications. In this study, numerous RF plasma cathodes have been designed and manufactured. Experimental measurements have been conducted to study the effects of geometric and operational parameters. Experimental results of this study show that the plasma generation and electron extraction characteristics of the RF plasma cathode device strongly depend on the geometric parameters such as chamber diameter, chamber length, orifice diameter, orifice length, as well as the operational parameters such as RF power and gas mass flow rate.

  7. Study of Organosilicon Plasma Polymer Used in Composite Layers with Biomedical Application

    NASA Astrophysics Data System (ADS)

    Radeva, E.; Pramatarova, L.; Pecheva, E.; Hikov, T.; Iacob, E.; Vanzetti, L.; Dimitrova, R.; Krasteva, N.; Spassov, T.; Fingarova, D.

    2010-01-01

    In this work we study the ability of plasma polymer (PP) films obtained from hexamethyldisiloxane (HMDS) on silica glass (SG) to induce hydroxyapatite (HA)-based composite layers from a mixture of simulated body fluid (SBF) and clear solution of detonation nanodiamond (DND) by a biomimetic process. The grown composites (PPHMDS/HADND) were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and Rutherford backscattering (RBS) techniques. FTIR spectra of the PPHMDS indicated diminishing of the polymer characteristic bands when the polymer is immersed in DND clear solution. Furthermore, after sample immersion in the SBF-DND mixture, the FTIR spectra showed the presence of carbonate-containing HA through the characteristic vibration modes of P-O in the phosphate group and C-O in the carbonate group. The formation of HA layers, rich in silica and/or carbon was confirmed by RBS and SEM. The cell viability measured after 7 days on the polymer surface is more then 95% for all samples. The results show that the PPHMDS is promising as a substrate for growing HA/DND layers and that the materials obtained are biocompatible. The variations of plasma polymerization conditions and modification of the composite layers will aid in using such materials for biomedical applications.

  8. Study of Organosilicon Plasma Polymer Used in Composite Layers with Biomedical Application

    SciTech Connect

    Radeva, E.; Pramatarova, L.; Pecheva, E.; Hikov, T.; Fingarova, D.; Iacob, E.; Vanzetti, L.; Dimitrova, R.; Krasteva, N.; Spassov, T.

    2010-01-21

    In this work we study the ability of plasma polymer (PP) films obtained from hexamethyldisiloxane (HMDS) on silica glass (SG) to induce hydroxyapatite (HA)-based composite layers from a mixture of simulated body fluid (SBF) and clear solution of detonation nanodiamond (DND) by a biomimetic process. The grown composites (PPHMDS/HADND) were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and Rutherford backscattering (RBS) techniques. FTIR spectra of the PPHMDS indicated diminishing of the polymer characteristic bands when the polymer is immersed in DND clear solution. Furthermore, after sample immersion in the SBF-DND mixture, the FTIR spectra showed the presence of carbonate-containing HA through the characteristic vibration modes of P-O in the phosphate group and C-O in the carbonate group. The formation of HA layers, rich in silica and/or carbon was confirmed by RBS and SEM. The cell viability measured after 7 days on the polymer surface is more then 95% for all samples. The results show that the PPHMDS is promising as a substrate for growing HA/DND layers and that the materials obtained are biocompatible. The variations of plasma polymerization conditions and modification of the composite layers will aid in using such materials for biomedical applications.

  9. Applications of atmospheric plasmas

    NASA Astrophysics Data System (ADS)

    Oldham, Christopher John

    Surface modification techniques using plasmas have historically been completed in a low pressure environment due to Pd (pressure x gap distance) considerations influencing the behavior of plasma generation. Generally, plasmas produced in a low pressure environment are of a non-thermal or cold nature. The basic feature of non-thermal plasmas is the majority of electrical energy used to generate the plasma is primarily used to produce energetic electrons for generating chemical species. Low pressure plasmas serve many purposes for materials processing. Since the plasma environment is contained within a closed vessel, the plasma can be controlled very easily. Low pressure plasmas have been used in many industries but the complexity associated with the large pumping stations and limitation to batch processing has motivated new work in the area of atmospheric plasmas. Atmospheric plasmas offer both economic and technical justification for use over low pressure plasmas. Since atmospheric plasmas can be operated at ambient conditions, lower costs associated with continuous processing and a decrease in the complexity of equipment validate atmospheric plasma processing as a next generation plasma-aided manufacturing process. In an effort to advance acceptance of atmospheric plasma processing into industry, a process was developed, the dielectric barrier discharge (DBD), in order to generate a homogeneous and non-thermal plasma discharge at ambient conditions. The discharge was applied to the reduction of known food borne pathogens, deposition of thin film materials, and modification of lignocellulosic biomass.

  10. Study of detonation nanodiamond - plasma polymerized hexamethildisiloxan composites for medical application

    NASA Astrophysics Data System (ADS)

    Pramatarova, L. D.; Krasteva, N. A.; Radeva, E. I.; Pecheva, E. V.; Dimitrova, R. P.; Hikov, T. A.; Mitev, D. P.; Hristova, K. T.; Altankov, G.

    2010-11-01

    The present study reports on how detonation nanodiamond (DND) - plasma poly(hexamethyldisiloxane) composites (PPHMDS) affect osteoblast cell behavior. It has been established that various modified DND nanoparticles (Ag-DND and Si-DND) can be readily integrated into virtually all polymer matrices. In particular, PPHDMS composites have been developed over the past few years because of the variety of their application as medical devices and implants. By incubation of MG-63 osteoblast-like cells on the surface of DND (Ag-DND and Si-DND) - PPHMDS composite, we tested the hypothesis that DND-based polymer composites can influence the adhesion behavior of MG-63 osteoblast-like cells. Morphological and structural characterization of DND, Ag-DND and Si-DND powders was carried out by XRD, HRTEM and EDS. For the study of the composite layers, deposited on cover glass (CG), FTIR spectroscopy has been performed in order to determine if the DND nanofiller can potentially modify the structural and chemical dynamics of the polymer matrix. The kinetic of static water contact angle of composite surfaces as a function of the as-used nanofiller DND's in polymer matrix was measured The results with MG-63 osteoblast-like cells suggest the potential of using DND-based polymer composites for application in engineering implantable scaffolds and devices.

  11. Application of the coded long-pulse technique to plasma line studies of the ionosphere

    NASA Technical Reports Server (NTRS)

    Djuth, Frank T.; Sulzer, Michael P.; Elder, John H.

    1994-01-01

    Recently, the coded long-pulse radar technique was tested at Arecibo Observatory, Puerto Rico using photoelectron-enhanced plasma lines in the daytime ionosphere. The technique immediately proved to be a powerful diagnostic tool for studying natural ionospheric phenomena. Our initial observations indicate that extremely accurate measurements of absolute electron density (0.01 to 0.03% error bars) can be achieved with an altitude resolution of 150 m and a temporal resolution of approx. 2 s. In addition, the technique provides information about electron density structure within a 150-m altitude cell and yields parameters from which the energy spectrum of suprathermal electrons (equal to or greater than 5 eV) can be deduced. Our earliest measurements are used to illustrate applications of the coded long-pulse technique to several aeronomic/ionsospheric areas of current interest. These include studies of neutral wave motions in the lower thermosphere, measurements of ion composition in the F(sub 1) region/upper ionosphere, and investigations of electron-gas thermal balance and photoelectron energy loss processes. The technique can be utilized to examine irregularity formation in the F region, probe electron acceleration processes in ionospheric modification experiments, verify the magnetic field dependence of Langmuir wave damping, and more generally test higher order corrections suggested for the Langmuir dispersion relation. It is anticipated that the latter tests will facilitate measurements of ionospheric currents.

  12. Biological and Agricultural Studies on Application of Discharge Plasma and Electromagnetic Fields 2.Sterilization by Electrical Discharges and Plasmas

    NASA Astrophysics Data System (ADS)

    Watanabe, Takayuki

    The use of electrical discharges and plasmas for sterilization is reviewed. Plasmas generated by a silent discharge, a pulse discharge, and a radio frequency discharge under atmospheric pressure have been used for sterilization. Furthermore, a microwave plasma, a radio frequency plasma, and a low temperature plasma with hydrogen peroxide under low pressure conditions have been also used for sterilization. Sterilization results from injury caused by the discharge current, and from the reaction of species affected by the discharge. A silent discharge with air or oxygen is most effective for the sterilization. Nitrogen discharge also has a significant effect, however, argon discharge does not have a significant effect.

  13. Studies on X-ray and Ion Emission from Dense Plasma Focus and Its Application in Material Modification

    NASA Astrophysics Data System (ADS)

    Bhuyan, Heman

    In the recent years, the radiations, namely X-rays and ions, from high temperature and high density plasma have become extremely important because of their applications in diverse areas. In micro- and nano-electronics industries, the current predominant trend of shrinkage of integrated circuits demands powerful, clean and bright pulsed X-ray sources. These sources are in hunt for not only electronics industries but also for other disciplines like micro-radiography, microscopy, crystallography etc.. Likewise, the quest for plasma based ion sources has been growing phenomenally during last decades for the synthesis of novel materials. These novel materials have plenty of applications in automotive, aerospace, biomedical and electronics industries. The need of present hour is to develop compact, cost-effective and efficient plasma based radiation sources so as to fulfill industrial requirements. The work presented in this thesis mainly focuses on how to operate the Dense Plasma Focus facility of Centre of Plasma Physics (CPP DPF) in an enhanced X-ray and ion emission mode. Four research problems are addressed in this thesis: (i) study of current sheet dynamics; (ii) investigation of X-ray emission; (iii) analysis of ion emission; and (iv) utilization of ions for material modification. Salient features of the different chapters of this thesis are described hereafter. Chapter 1, in addition to a brief introduction to the importance of plasma physics, provides information on X-ray and ion sources and their current scenario of industrial applications. Besides, this chapter provides a short introduction to DPF device along with current sheet dynamics and other related plasma phenomena. Chapter 2 presents the design and fabrication details of CPP DPF facility (pulsed power driver, plasma focus tube with pumping system) along with the basic diagnostic techniques (Rogowski coil and resistive voltage divider). In addition, the discharge performance of DPF facility, which is

  14. Studies of air, water, and ethanol vapor atmospheric pressure plasmas for antimicrobial applications.

    PubMed

    Ferrell, James R; Bogovich, Erinn R; Lee, Nicholas R; Gray, Robert L; Pappas, Daphne D

    2015-06-25

    The generation of air-based plasmas under atmospheric plasma conditions was studied to assess their antimicrobial efficacy against commonly found pathogenic bacteria. The mixture of initial gases supplied to the plasma was found to be critical for the formation of bactericidal actives. The optimal gas ratio for bactericidal effect was determined to be 99% nitrogen and 1% oxygen, which led to a 99.999% reduction of a pathogenic strain of Escherichia coli on stainless steel surfaces. The experimental substrate, soil load on the substrate, flow rate of the gases, and addition of ethanol vapor all were found to affect antimicrobial efficacy of studied plasmas. Optical emission spectroscopy was used to identify the species that were present in the plasma bulk phase for multiple concentrations of nitrogen and oxygen ratios. The collected spectra indicate a unique series of bands present in the ultraviolet region of the electromagnetic spectrum that can be attributed to nitric oxide species known to be highly antimicrobial. This intense spectral profile dramatically changes as the concentration of nitrogen decreases.

  15. Studies of air, water, and ethanol vapor atmospheric pressure plasmas for antimicrobial applications.

    PubMed

    Ferrell, James R; Bogovich, Erinn R; Lee, Nicholas R; Gray, Robert L; Pappas, Daphne D

    2015-01-01

    The generation of air-based plasmas under atmospheric plasma conditions was studied to assess their antimicrobial efficacy against commonly found pathogenic bacteria. The mixture of initial gases supplied to the plasma was found to be critical for the formation of bactericidal actives. The optimal gas ratio for bactericidal effect was determined to be 99% nitrogen and 1% oxygen, which led to a 99.999% reduction of a pathogenic strain of Escherichia coli on stainless steel surfaces. The experimental substrate, soil load on the substrate, flow rate of the gases, and addition of ethanol vapor all were found to affect antimicrobial efficacy of studied plasmas. Optical emission spectroscopy was used to identify the species that were present in the plasma bulk phase for multiple concentrations of nitrogen and oxygen ratios. The collected spectra indicate a unique series of bands present in the ultraviolet region of the electromagnetic spectrum that can be attributed to nitric oxide species known to be highly antimicrobial. This intense spectral profile dramatically changes as the concentration of nitrogen decreases. PMID:25810273

  16. Argon plasma inductively coupled plasma reactive ion etching study for smooth sidewall thin film lithium niobate waveguide application

    NASA Astrophysics Data System (ADS)

    Ulliac, G.; Calero, V.; Ndao, A.; Baida, F. I.; Bernal, M.-P.

    2016-03-01

    Lithium Niobate (LN) exhibits unique physical properties such as remarkable electro-optical coefficients and it is thus an excellent material for a wide range of fields like optic communications, lasers, nonlinear optical applications, electric field optical sensors etc. In order to further enhance the optical device performance and to be competitive with silicon photonics, sub-micrometric thickness lithium niobate films are crucial. A big step has been achieved with the development of LN thin films by using smart cut technology and wafer bonding and these films are nowadays available in the market. However, it is a challenge to obtain the requirements of the high quality thin LN film waveguide. In this letter, we show smooth ridge waveguides fabricated on 700 nm thickness thin film lithium niobate (TFLN). The fabrication has been done by developing and optimizing three steps of the technological process, the mask fabrication, the plasma etching, and a final cleaning wet etching step in order to remove the lithium niobate redeposition on the side walls. We have obtained single mode propagation with light overall losses of only 5 dB/cm.

  17. Application of the floating-potential probe for studies of low frequency oscillations in a plasma

    NASA Technical Reports Server (NTRS)

    Dzhakov, B. Y.

    1973-01-01

    The proper interpretation of the results obtained from measurements of the floating potential of an electrostatic probe may cause difficulties in time varying plasmas. The following limitations of the method are considered: the charge separation in the plasma, the influence of the input capacity of the measuring circuit, and the influence of the layer capacity near the probe. A detailed analysis is carried out in the cases of moving striations and ion acoustic waves. A simple measuring technique is suggested for ion acoustic studies, giving detailed information about ion density oscillations.

  18. Industrial applications of thermal plasmas

    NASA Astrophysics Data System (ADS)

    Szente, Roberto Nunes

    1995-09-01

    The main characteristics and applications of thermal plasmas are reviewed here. The industrial applications of thermal plasmas can be divided in: low power-cutting, welding, spraying; metallurgical and steelmaking; materials; environment. Some of the processes described in this article include: powder spraying, metal refining, tundish and laddle heating, production of ferroalloys and ceramic materials, and treatment of residues (aluminum scrap, steel dusts, ashes, hospital wastes, electroplating mud). The use of thermal plasmas in the environment arena in particular has attracted increasingly attention as the regulations for disposal of residues become tougher. More research and development is needed particularly for decreasing the erosion of the electrodes of plasma torches and fundamental understanding of high temperature chemistry, heat transfer, and electric arcs for broadening the applications of thermal plasmas.

  19. Magnetic-Nozzle Studies for Fusion Propulsion Applications: Gigawatt Plasma Source Operation and Magnetic Nozzle Analysis

    NASA Technical Reports Server (NTRS)

    Gilland, James H.; Mikekkides, Ioannis; Mikellides, Pavlos; Gregorek, Gerald; Marriott, Darin

    2004-01-01

    This project has been a multiyear effort to assess the feasibility of a key process inherent to virtually all fusion propulsion concepts: the expansion of a fusion-grade plasma through a diverging magnetic field. Current fusion energy research touches on this process only indirectly through studies of plasma divertors designed to remove the fusion products from a reactor. This project was aimed at directly addressing propulsion system issues, without the expense of constructing a fusion reactor. Instead, the program designed, constructed, and operated a facility suitable for simulating fusion reactor grade edge plasmas, and to examine their expansion in an expanding magnetic nozzle. The approach was to create and accelerate a dense (up to l0(exp 20)/m) plasma, stagnate it in a converging magnetic field to convert kinetic energy to thermal energy, and examine the subsequent expansion of the hot (100's eV) plasma in a subsequent magnetic nozzle. Throughout the project, there has been a parallel effort between theoretical and numerical design and modelling of the experiment and the experiment itself. In particular, the MACH2 code was used to design and predict the performance of the magnetoplasmadynamic (MPD) plasma accelerator, and to design and predict the design and expected behavior for the magnetic field coils that could be added later. Progress to date includes the theoretical accelerator design and construction, development of the power and vacuum systems to accommodate the powers and mass flow rates of interest to out research, operation of the accelerator and comparison to theoretical predictions, and computational analysis of future magnetic field coils and the expected performance of an integrated source-nozzle experiment.

  20. Enantioselective analysis of 4-hydroxycyclophosphamide in human plasma with application to a clinical pharmacokinetic study.

    PubMed

    de Castro, Francine Attié; Scatena, Gabriel dos Santos; Rocha, Otávio Pelegrino; Marques, Maria Paula; Cass, Quézia Bezerra; Simões, Belinda Pinto; Lanchote, Vera Lucia

    2016-02-01

    Cyclophosphamide (CY) is one of the most common immunosuppressive agents used in autologous hematopoietic stem cell transplantation. CY is a prodrug and is metabolized to active 4-hydroxycyclophosphamide (HCY). Many authors have suggested an association between enantioselectivity in CY metabolism and treatment efficacy and/or complications. This study describes the development and validation of an analytical method of HCY enantiomers in human plasma by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) that can be applied to pharmacokinetic studies, filling this gap in the literature. HCY enantiomers previously derivatized with phenylhydrazine were extracted from 200-μL plasma aliquots spiked with antipyrine as internal standard and a mixture of hexane and dichloromethane (80:20, v/v) was used as the extraction solvent. The derivatized HCY enantiomers were resolved on a Chiracel(®) OD-R column using water:acetonitrile:formic acid (55:45:0.2, v/v) as the mobile phase. No matrix effect was observed and the analysis of HCY enantiomers was linear for plasma concentrations of 5-5000ng of each enantiomer/mL plasma. The coefficients of variation and inaccuracy calculated in precision and accuracy assessments were less than 15%. HCY was stable in human plasma after three successive freeze/thaw cycles, during 3h at room temperature, and in the autosampler at 4°C for 24h after processing, with deviation values less than 15%. The method was applied to evaluate the kinetic disposition of HCY in a patient with multiple sclerosis who was pretreated with intravenous racemic CY for stem cell transplantation. The clinical study showed enantioselectivity in the pharmacokinetics of HCY.

  1. High-Performance Liquid Chromatographic Determination of Rivastigmine in Human Plasma for Application in Pharmacokinetic Studies

    PubMed Central

    Amini, Hossein; Ahmadiani, Abolhassan

    2010-01-01

    A simple and reproducible HPLC method with spectrophotometric detection was developed for determination of rivastigmine in human plasma. Liquid-liquid extraction of rivastigmine and donepezil (as internal standard) from plasma samples was performed with 1-butanol/n-hexane (2:98 v/v) in alkaline condition followed by back-extraction into diluted acetic acid. Chromatography was carried out using a Silica column (250 mm × 4.6 mm, 5 μm) under isocratic elution with acetonitrile-50 mM aqueous sodium dihydrogen phosphate (17: 83 v/v, pH 3.1. Analyses were run at a flow-rate of 1.3 mL/min at of 50°C. The recovery was 90.8% and 95.7% for rivastigmine and the internal standard donepezil, respectively. The precision of the method was 2.6% to 9.1% over the concentration range of 0.5-16 ng/mL for rivastigmine in plasma with a linearity greater than 0.999. The method was specific and sensitive, with a quantification limit of 0.5 ng/mL and a detection limit of 0.2 ng/mL in plasma. The method was used for a bioequivalence study in healthy subjects. PMID:24363716

  2. Study of a cesium plasma as a selective emitter for thermophotovoltaic applications

    NASA Technical Reports Server (NTRS)

    Lowe, R.; Goradia, C.; Goradia, M.; Chubb, Donald L.

    1990-01-01

    This experimental study evaluates the potential of a cesium plasma as an emitter for a thermophotovoltaic (TPV) energy conversion system. A cesium plasma, as a result of the ground-state transitions of its single outer-shell electron, produces large amounts of radiation in the 850-890-nm wavelength region. This would provide excellent coupling to silicon, gallium arsenide, and indium phosphide photovoltaic cells. Measurements of the radiative efficiency, the sum of the power at the 852 and 894 nm wavelengths relative to the total emitted power, were made and correlated to the plasma operating variables. It was determined that, for atomic density in the range (3-6) x 10 exp 21/cu cm and electron temperature in the range 2000-3000 K, radiative efficiencies in excess of 70 percent are attainable. This would indicate that a cesium plasma with its selective emission characteristics and low electron operating temperatures of 2000-3000 K would be an excellent candidate as an emitter in a TPV system.

  3. Numerical study of capacitive coupled HBr/Cl2 plasma discharge for dry etch applications

    NASA Astrophysics Data System (ADS)

    Gul, Banat; Ahmad, Iftikhar; Zia, Gulfam; Aman-ur-Rehman

    2016-09-01

    HBr/Cl2 plasma discharge is investigated to study the etchant chemistry of this discharge by using the self-consistent fluid model. A comprehensive set of gas phase reactions (83 reactions) including primary processes such as excitation, dissociation, and ionization are considered in the model along with 24 species. Our findings illustrate that the densities of neutral species (i.e., Br, HCl, Cl, H, and H2) produced in the reactor are higher than charged species (i.e., Cl2+, Cl-, HBr+, and Cl+). Density profile of neutral and charged species followed bell shaped and double humped distributions, respectively. Increasing Cl2 fraction in the feedback gases (HBr/Cl2 from 90/10 to 10/90) promoted the production of Cl, Cl+, and Cl2+ in the plasma, indicating that chemical etching pathway may be preferred at high Cl-environment. These findings pave the way towards controlling/optimizing the Si-etching process.

  4. Experimental studies of lithium-based surface chemistry for fusion plasma-facing materials applications

    NASA Astrophysics Data System (ADS)

    Allain, J. P.; Rokusek, D. L.; Harilal, S. S.; Nieto-Perez, M.; Skinner, C. H.; Kugel, H. W.; Heim, B.; Kaita, R.; Majeski, R.

    2009-06-01

    Lithium has enhanced the operational performance of fusion devices such as: TFTR, CDX-U, FTU, T-11 M, and NSTX. Lithium in the solid and liquid state has been studied extensively in laboratory experiments including its erosion and hydrogen-retaining properties. Reductions in physical sputtering up to 40-60% have been measured for deuterated solid and liquid lithium surfaces. Computational modeling indicates that up to a 1:1 deuterium volumetric retention in lithium is possible. This paper presents the results of systematic in situ laboratory experimental studies on the surface chemistry evolution of ATJ graphite under lithium deposition. Results are compared to post-mortem analysis of similar lithium surface coatings on graphite exposed to deuterium discharge plasmas in NSTX. Lithium coatings on plasma-facing components in NSTX have shown substantial reduction of hydrogenic recycling. Questions remain on the role lithium surface chemistry on a graphite substrate has on particle sputtering (physical and chemical) as well as hydrogen isotope recycling. This is particularly due to the lack of in situ measurements of plasma-surface interactions in tokamaks such as NSTX. Results suggest that the lithium bonding state on ATJ graphite is lithium peroxide and with sufficient exposure to ambient air conditions, lithium carbonate is generated. Correlation between both results is used to assess the role of lithium chemistry on the state of lithium bonding and implications on hydrogen pumping and lithium sputtering. In addition, reduction of factors between 10 and 30 reduction in physical sputtering from lithiated graphite compared to pure lithium or carbon is also measured.

  5. Antimicrobial Applications of Ambient--Air Plasmas

    NASA Astrophysics Data System (ADS)

    Pavlovich, Matthew John

    The emerging field of plasma biotechology studies the applications of the plasma phase of matter to biological systems. "Ambient-condition" plasmas created at or near room temperature and atmospheric pressure are especially promising for biomedical applications because of their convenience, safety to patients, and compatibility with existing medical technology. Plasmas can be created from many different gases; plasma made from air contains a number of reactive oxygen and nitrogen species, or RONS, involved in various biological processes, including immune activity, signaling, and gene expression. Therefore, ambient-condition air plasma is of particular interest for biological applications. To understand and predict the effects of treating biological systems with ambient-air plasma, it is necessary to characterize and measure the chemical species that these plasmas produce. Understanding both gaseous chemistry and the chemistry in plasma-treated aqueous solution is important because many biological systems exist in aqueous media. Existing literature about ambient-air plasma hypothesizes the critical role of reactive oxygen and nitrogen species; a major aim of this dissertation is to better quantify RONS by produced ambient-air plasma and understand how RONS chemistry changes in response to different plasma processing conditions. Measurements imply that both gaseous and aqueous chemistry are highly sensitive to operating conditions. In particular, chemical species in air treated by plasma exist in either a low-power ozone-dominated mode or a high-power nitrogen oxide-dominated mode, with an unstable transition region at intermediate discharge power and treatment time. Ozone (O3) and nitrogen oxides (NO and NO2, or NOx) are mutually exclusive in this system and that the transition region corresponds to the transition from ozone- to nitrogen oxides-mode. Aqueous chemistry agrees well with to air plasma chemistry, and a similar transition in liquid-phase composition

  6. [Plasma technology for biomedical material applications].

    PubMed

    Liu, Z; Li, X

    2000-03-01

    In this paper is introduced the plasma technology for the applications of several species biomaterial such as ophthalmological material, drug delivery system, tissue culture material, blood anticoagulant material as well as plasma surface clearing and plasma sterilization, and so on.

  7. Plasma Sterilization Technology for Spacecraft Applications

    NASA Technical Reports Server (NTRS)

    Fraser, S. J.; Olson, R. L.; Leavens, W. M.

    1975-01-01

    The application of plasma gas technology to sterilization and decontamination of spacecraft components is considered. Areas investigated include: effective sterilizing ranges of four separate gases; lethal constituents of a plasma environment; effectiveness of plasma against a diverse group of microorganisms; penetrating efficiency of plasmas for sterilization; and compatibility of spacecraft materials with plasma environments. Results demonstrated that plasma gas, specifically helium plasma, is a highly effective sterilant and is compatible with spacecraft materials.

  8. A chamber experiment for the feasibility study of an artificial plasma reflector for OTH radar applications

    NASA Technical Reports Server (NTRS)

    Kuo, S. P.; Zhang, Y. S.; Ji, Q. H.; Miller, P. E.; Tiong, K. K.

    1989-01-01

    The feasibility of using two intersecting beams for plasma generation in the upper atmosphere as an over-the-horizon radar reflector was investigated. A cube was filled with dry air to a pressure corresponding to the simulated altitude, and two components of a split microwave beam were fed into the cube at right angles. Plasma layers were generated where the two beams intersected. Three critical issues were addressed: (1) reflectivity of the generated plasma layers; (2) propagation of high power microwave pulses; and (3) lifetime of the plasma.

  9. Quantification of taraxasterol in rat plasma by LC/MS/MS: application to a pharmacokinetic study.

    PubMed

    Zhang, Nan; Pang, Li; Dong, Ning; Xu, Dahai; Xu, Hong

    2015-11-01

    Taraxasterol, a pentacyclic triterpene from Taraxacum officinale, is one of the main active constituents of the herb. This study developed and validated a highly selective and sensitive liquid chromatography/tandem mass spectrometry for the determination of taraxasterol in rat plasma over the range of 9.0-5000 ng/mL. Chromatographic separation was achieved on a C18 (4.6 × 50 mm, 5.0 µm) column with methanol-isopropanol-water-formic acid (80:10:10:0.1, v/v/v/v) as mobile phase with an isocratic elution. The flow rate was 0.7 mL/min. After adding cucurbitacin IIa as an internal standard (IS), liquid-liquid extraction was used for sample preparation using ethyl acetate. The atmospheric pressure chemical ionization source was applied and operated in positive ion mode. Selected reaction monitoring mode was used for the quantification of transition ions m/z 409.4 → 137.1 for taraxasterol and m/z 503.4 → 113.1 for IS. The mean recoveries of taraxasterol in rat plasma ranged from 85.3 to 87.2%. The matrix effects for taraxasterol were between 98.5 and 104.0%. Intra- and inter-day precision were both <11.8%, and the accuracy of the method ranged from -7.0 to 12.9%. The method was successfully applied to a pharmacokinetic study of taraxasterol after oral administration of 7.75, 15.5 and 31.0 mg/kg in rats. PMID:25873241

  10. Novel LC- ESI-MS/MS method for desvenlafaxine estimation human plasma: application to pharmacokinetic study.

    PubMed

    Kancharla, Pushpa Kumari; Kondru, Venu Gopal Raju; Dannana, Gowri Sankar

    2016-02-01

    A simple, sensitive and specific liquid chromatography tandem mass spectrometry (LC-ESI-MS/MS) method was developed for the quantification of desvenlafaxine in human plasma using desvenlafaxine d6 as an internal standard (IS). Chromatographic separation was performed using a Thermo-BDS hypersil C8 column (50 × 4.6 mm, 3 µm) with an isocratic mobile phase composed of 5 mM ammonium acetate buffer: methanol (20:80, v/v), at a flow rate of 0.80 mL/min. Desvenlafaxine and desvenlafaxine d6 were detected with proton adducts at m/z 264.2/58.1 and 270.2/ 64.1 in multiple reaction monitoring positive mode, respectively. Liquid-liquid extraction was used to extract the drug and the IS. The method was linear over the concentration range 1.001-400.352 ng/mL with a correlation coefficient of ≥0.9994. This method demonstrated intra and inter-day precision within 0.7-5.5 and 1.9-6.8%, and accuracy within 95.3-107.4 and 93.4-99.5%. Desvenlafaxine was found to be stable throughout the freeze-thaw cycles, bench-top and long-term matrix stability studies. The developed and validated method can be successfully applied for the bioequivalence/pharmacokinetic studies of desvenlafaxine in pharmaceutical dosage forms.

  11. Study of a non-equilibrium plasma pinch with application for microwave generation

    NASA Astrophysics Data System (ADS)

    Al Agry, Ahmad Farouk

    The Non-Equilibrium Plasma Pinch (NEPP), also known as the Dense Plasma Focus (DPF) is well known as a source of energetic ions, relativistic electrons and neutrons as well as electromagnetic radiation extending from the infrared to X-ray. In this dissertation, the operation of a 15 kJ, Mather type, NEPP machine is studied in detail. A large number of experiments are carried out to tune the machine parameters for best performance using helium and hydrogen as filling gases. The NEPP machine is modified to be able to extract the copious number of electrons generated at the pinch. A hollow anode with small hole at the flat end, and a mock magnetron without biasing magnetic field are built. The electrons generated at the pinch are very difficult to capture, therefore a novel device is built to capture and transport the electrons from the pinch to the magnetron. The novel cup-rod-needle device successfully serves the purpose to capture and transport electrons to monitor the pinch current. Further, the device has the potential to field emit charges from its needle end acting as a pulsed electron source for other devices such as the magnetron. Diagnostics tools are designed, modeled, built, calibrated, and implemented in the machine to measure the pinch dynamics. A novel, UNLV patented electromagnetic dot sensors are successfully calibrated, and implemented in the machine. A new calibration technique is developed and test stands designed and built to measure the dot's ability to track the impetus signal over its dynamic range starting and ending in the noise region. The patented EM-dot sensor shows superior performance over traditional electromagnetic sensors, such as Rogowski coils. On the other hand, the cup-rod structure, when grounded on the rod side, serves as a diagnostic tool to monitor the pinch current by sampling the actual current, a quantity that has been always very challenging to measure without perturbing the pinch. To the best of our knowledge, this method

  12. Approximate models for the study of exponential changed quantities: Application on the plasma waves growth rate or damping

    SciTech Connect

    Xaplanteris, C. L.; Xaplanteris, L. C.; Leousis, D. P.

    2014-03-15

    Many physical phenomena that concern the research these days are basically complicated because of being multi-parametric. Thus, their study and understanding meets with big if not unsolved obstacles. Such complicated and multi-parametric is the plasmatic state as well, where the plasma and the physical quantities that appear along with it have chaotic behavior. Many of those physical quantities change exponentially and at most times they are stabilized by presenting wavy behavior. Mostly in the transitive state rather than the steady state, the exponentially changing quantities (Growth, Damping etc) depend on each other in most cases. Thus, it is difficult to distinguish the cause from the result. The present paper attempts to help this difficult study and understanding by proposing mathematical exponential models that could relate with the study and understanding of the plasmatic wavy instability behavior. Such instabilities are already detected, understood and presented in previous publications of our laboratory. In other words, our new contribution is the study of the already known plasmatic quantities by using mathematical models (modeling and simulation). These methods are both useful and applicable in the chaotic theory. In addition, our ambition is to also conduct a list of models useful for the study of chaotic problems, such as those that appear into the plasma, starting with this paper's examples.

  13. Validation of an HPLC-MS-MS assay for determination of morellic acid in rat plasma: application to pharmacokinetic studies.

    PubMed

    Li, Yang; Zhang, Qi; Jiang, Daqing

    2015-01-01

    A selective and rapid high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) was developed for the quantification of morellic acid in rat plasma. HPLC was performed using a Capcell MG C18 (50 × 4.6 mm, i.d., 5 µm) column, and isocratic elution with water-acetonitrile (20:80, v/v) at a flow rate of 0.5 mL/min. Sample preparation of analyte and internal standard (gambogic acid) involved liquid-liquid extraction using ethyl acetate-isopropanol (1:1, v/v) from 50 µL plasma. The precursor → production transitions for analyte and IS were m/z 559.4 → 471.3, and m/z 627.3 → 583.3, respectively, and were monitored on a triple-quadrupole mass spectrometer, operating in negative ion scan mode. The method was validated across the dynamic concentration range of 20-7,500 ng/mL for morellic acid, with a fast run time of 6.0 min. The analytical method measured concentrations of morellic acid with accuracy (% bias) of ≤6.4% and precision (% RSD) of ≤14.0%. Morellic acid was stable during the battery of stability studies. Finally, the applicability of this assay has been successfully demonstrated in vivo pharmacokinetic studies in Sprague-Dawley rats. This method will therefore be useful for further preclinical and clinical pharmacokinetic studies of morellic acid. PMID:26071609

  14. Preliminary study to assay plasma amethocaine concentrations after topical application of a new local anaesthetic cream containing amethocaine.

    PubMed

    Mazumdar, B; Tomlinson, A A; Faulder, G C

    1991-10-01

    Plasma concentrations of amethocaine were measured after topical application of amethocaine cream 2 g (5% w/w) to the dorsum of the right hand of 10 adult volunteers. The cream was applied for 240 min and plasma was assayed for amethocaine and its metabolite p-n-butylaminobenzoic acid at 0, 30, 60, 90, 120 and 240 min in all 10 volunteers, and at 360 min in seven volunteers, by high pressure liquid chromatography. No amethocaine was detected in the plasma of seven volunteers. Plasma concentrations of amethocaine up to 0.20 mg litre-1 were observed in three volunteers. No significant side effects were seen and pain scores on insertion of a 16-gauge cannula were 0 in all subjects. We conclude that the absence of clinical toxicity in the 10 healthy volunteers was a reflection of slow absorption and tissue hydrolysis of amethocaine after topical dermal application.

  15. Laboratory and Space Plasma Studies

    NASA Astrophysics Data System (ADS)

    Hyman, Ellis

    1996-08-01

    The work performed by Science Applications International Corporation (SAIC) on this contract, 'Laboratory and Space Plasma Studies,' Contract Number N00014-93-C-2178, SAIC Project Number 01-0157-03-6984, encompasses a wide range of topics in experimental, computational, and analytical laboratory and space plasma physics. The accomplishments described in this report have been in support of the programs of the Laser Plasma Branch (Code 6730) and other segments of the Plasma Physics Division at the Naval Research Laboratory (NRL) and cover the period 27 September 1993 to August 1, 1996. SAIC's efforts have been supported by subcontracts or consulting agreements with Pulse Sciences, Inc., Clark Richardson, and Biskup Consulting Engineers, Pharos Technical Enterprises, Plex Corporation, Cornell University, Stevens Institute of Technology, the University of Connecticut, Plasma Materials and Technologies, Inc., and GaSonics International, Inc. In the following discussions section we will describe each of the topics investigated and the results obtained. Much of the research work has resulted in journal publications and NRL Memorandum Reports in which the investigation is described in detail. These reports are included as Appendices to this Final Report.

  16. Bodies in flowing plasmas - Laboratory studies

    NASA Technical Reports Server (NTRS)

    Stone, N. H.; Samir, U.

    1981-01-01

    A brief review of early rudimentary laboratory studies of bodies in flowing, rarefied plasmas is presented (e.g., Birkeland, 1908), along with a discussion of more recent parametric studies conducted in steady plasma wind tunnels, which includes the study by Hall et al. (1964), in which a strong ion density enhancement in the center of the ion void created downstream from the body was observed. Good agreement was found between the experimental results and theoretical calculations which omit ion thermal motion. Examples in which in situ data on the interaction between satellites and the ionospheric plasma have been elucidated by the laboratory results are presented, and include evidence for a midwake axial ion peak, and ion current density in the near-wake region. The application of the ionospheric laboratory to basic space plasma physics is discussed, and its application to some types of solar system plasma phenomena is illustrated.

  17. Test of prototype ITER vacuum ultraviolet spectrometer and its application to impurity study in KSTAR plasmas.

    PubMed

    Seon, C R; Hong, J H; Jang, J; Lee, S H; Choe, W; Lee, H H; Cheon, M S; Pak, S; Lee, H G; Biel, W; Barnsley, R

    2014-11-01

    To optimize the design of ITER vacuum ultraviolet (VUV) spectrometer, a prototype VUV spectrometer was developed. The sensitivity calibration curve of the spectrometer was calculated from the mirror reflectivity, the grating efficiency, and the detector efficiency. The calibration curve was consistent with the calibration points derived in the experiment using the calibrated hollow cathode lamp. For the application of the prototype ITER VUV spectrometer, the prototype spectrometer was installed at KSTAR, and various impurity emission lines could be measured. By analyzing about 100 shots, strong positive correlation between the O VI and the C IV emission intensities could be found.

  18. Test of prototype ITER vacuum ultraviolet spectrometer and its application to impurity study in KSTAR plasmas.

    PubMed

    Seon, C R; Hong, J H; Jang, J; Lee, S H; Choe, W; Lee, H H; Cheon, M S; Pak, S; Lee, H G; Biel, W; Barnsley, R

    2014-11-01

    To optimize the design of ITER vacuum ultraviolet (VUV) spectrometer, a prototype VUV spectrometer was developed. The sensitivity calibration curve of the spectrometer was calculated from the mirror reflectivity, the grating efficiency, and the detector efficiency. The calibration curve was consistent with the calibration points derived in the experiment using the calibrated hollow cathode lamp. For the application of the prototype ITER VUV spectrometer, the prototype spectrometer was installed at KSTAR, and various impurity emission lines could be measured. By analyzing about 100 shots, strong positive correlation between the O VI and the C IV emission intensities could be found. PMID:25430310

  19. Practical applications of plasma surface modification

    SciTech Connect

    Smith, M.D.

    1993-12-01

    Radio frequency activated gas plasma is an environmentally conscious manufacturing process which provides surface treatments for improved product quality. Plasma processing offers significant potential for reducing the use of solvents and other wet processing chemicals now used in surface treatments such as cleaning, activation for bonding, and moisture removal. Plasma treatments are generally accomplished without creating hazardous waste streams to dispose of. Plasma process development and application is ongoing at Allied Signal Inc., Kansas City Division.

  20. Industrial Applications of Low Temperature Plasmas

    SciTech Connect

    Bardsley, J N

    2001-03-15

    The use of low temperature plasmas in industry is illustrated by the discussion of four applications, to lighting, displays, semiconductor manufacturing and pollution control. The type of plasma required for each application is described and typical materials are identified. The need to understand radical formation, ionization and metastable excitation within the discharge and the importance of surface reactions are stressed.

  1. Plasma chemistry and its applications

    NASA Technical Reports Server (NTRS)

    Hozumi, K.

    1980-01-01

    The relationship between discharge phenomena and plasma chemistry, as well as the equipment and mechanisms of plasma chemical reactions are described. Various areas in which plasma chemistry is applied are surveyed, such as: manufacturing of semiconductor integrated circuits; synthetic fibers; high polymer materials for medical uses; optical lenses; and membrane filters (reverse penetration films).

  2. Atmospheric Pressure Plasma Process And Applications

    SciTech Connect

    Peter C. Kong; Myrtle

    2006-09-01

    This paper provides a general discussion of atmospheric-pressure plasma generation, processes, and applications. There are two distinct categories of atmospheric-pressure plasmas: thermal and nonthermal. Thermal atmospheric-pressure plasmas include those produced in high intensity arcs, plasma torches, or in high intensity, high frequency discharges. Although nonthermal plasmas are at room temperatures, they are extremely effective in producing activated species, e.g., free radicals and excited state atoms. Thus, both thermal and nonthermal atmosphericpressure plasmas are finding applications in a wide variety of industrial processes, e.g. waste destruction, material recovery, extractive metallurgy, powder synthesis, and energy conversion. A brief discussion of recent plasma technology research and development activities at the Idaho National Laboratory is included.

  3. The diverse applications of plasma

    SciTech Connect

    Sharma, Mukul Darwhekar, Gajanan; Dubey, Shivani; Jain, Sudhir Kumar

    2015-07-31

    Plasma being the fourth state of matter has always been an attraction for Physicists and Chemists. With the advent of time, plasma energy has been recognized in having widening horizons in the field of Biomedical Sciences. Plasma medicine can be subdivided into three main fields; Non-thermal atmospheric-pressure direct plasma for medical therapy; Plasma-assisted modification of bio-relevant surfaces and Plasma-based bio-decontamination and sterilization. The basis of the research is that as it has free carrier molecules, it has the ability to target specific cells and regulate functions like wound healing. Plasma does not harm healthy human cells but can kill bacteria and possibly even cancer cells to help treat various diseases. Nosocomial infection control, prevention and containment of contagious diseases, disinfection of medical devices, surface treatment (heat and UV sensitive surfaces) are research of interest. Recent success in generating plasma at very low temperature ie. Cold plasma makes the therapy painless. It has the ability to activate cellular responses and important mechanisms in the body. They target specific molecules such as prothrombin for blood coagulation, cytokines for killing bacteria, and angiogenesis for tissue regeneration. Plasma has bactericidal, fungicidal and virucidal properties. Plasma technology has flourishing future in diverse fields like Textiles, Nanofabrication, Automotives, Waste management, Microbiology, Food Hygiene, Medical Science like Skin treatments, sterilisation of wounds, Hand disinfection, Dental treatments etc. Food hygiene using plasma can be achieved in disinfection of food containers, food surface disinfection, hygiene in food handling, preparation and packaging. Therefore Plasma is most promising field for budding Scientist for fluorishing research in Biological Sciences.

  4. The diverse applications of plasma

    NASA Astrophysics Data System (ADS)

    Sharma, Mukul; Dubey, Shivani; Darwhekar, Gajanan; Jain, Sudhir Kumar

    2015-07-01

    Plasma being the fourth state of matter has always been an attraction for Physicists and Chemists. With the advent of time, plasma energy has been recognized in having widening horizons in the field of Biomedical Sciences. Plasma medicine can be subdivided into three main fields; Non-thermal atmospheric-pressure direct plasma for medical therapy; Plasma-assisted modification of bio-relevant surfaces and Plasma-based bio-decontamination and sterilization. The basis of the research is that as it has free carrier molecules, it has the ability to target specific cells and regulate functions like wound healing. Plasma does not harm healthy human cells but can kill bacteria and possibly even cancer cells to help treat various diseases. Nosocomial infection control, prevention and containment of contagious diseases, disinfection of medical devices, surface treatment (heat and UV sensitive surfaces) are research of interest. Recent success in generating plasma at very low temperature ie. Cold plasma makes the therapy painless. It has the ability to activate cellular responses and important mechanisms in the body. They target specific molecules such as prothrombin for blood coagulation, cytokines for killing bacteria, and angiogenesis for tissue regeneration. Plasma has bactericidal, fungicidal and virucidal properties. Plasma technology has flourishing future in diverse fields like Textiles, Nanofabrication, Automotives, Waste management, Microbiology, Food Hygiene, Medical Science like Skin treatments, sterilisation of wounds, Hand disinfection, Dental treatments etc. Food hygiene using plasma can be achieved in disinfection of food containers, food surface disinfection, hygiene in food handling, preparation and packaging. Therefore Plasma is most promising field for budding Scientist for fluorishing research in Biological Sciences.

  5. Study of supersonic plasma technology jets

    NASA Astrophysics Data System (ADS)

    Selezneva, Svetlana; Gravelle, Denis; Boulos, Maher; van de Sanden, Richard; Schram, Dc

    2001-10-01

    Recently some new techniques using remote thermal plasma for thin film deposition and plasma chemistry processes were developed. These techniques include PECVD of diamonds, diamond-like and polymer films; a-C:H and a-Si:H films. The latter are of especial interest because of their applications for solar cell production industry. In remote plasma deposition, thermal plasma is formed by means of one of traditional plasma sources. The chamber pressure is reduced with the help of continuous pumping. In that way the flow is accelerated up to the supersonic speed. The plasma expansion is controlled using a specific torch nozzle design. To optimize the deposition process detailed knowledge about the gas dynamic structure of the jet and chemical kinetics mechanisms is required. In the paper, we show how the flow pattern and the character of the deviations from local thermodynamic equilibrium differs in plasmas generated by different plasma sources, such as induction plasma torch, traditional direct current arc and cascaded arc. We study the effects of the chamber pressure, nozzle design and carrier gas on the resulting plasma properties. The analysis is performed by means of numerical modeling using commercially available FLUENT program with incorporated user-defined subroutines for two-temperature model. The results of continuum mechanics approach are compared with that of the kinetic Monte Carlo method and with the experimental data.

  6. Determination of tanshinone I in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies.

    PubMed

    Du, Wei; Wei, Yu-Hui; Zhao, Gang; Qin, Hong-Yan; Wu, Xin-An

    2008-09-01

    This paper describes a rapid and sensitive high-performance liquid chromatographic (HPLC) method for the determination of the concentration of tanshinone I in rat plasma, and applies the method to pharmacokinetic study. The plasma is deproteinized with acetonitrile containing an internal standard (estradiolbenzoate). The HPLC assay is carried out using a Cosmosil C18 column. The mobile phase is acetonitrile, 0.05 mol/L(-1) ammonium acetate buffer with 1% acetic acid (66:34, v/v). The flow rate is 1.0 mL/min. The detection wavelength is set at 263 nm. The assay accuracy is better than 92%, and the precision of tanshinone I at low to high concentrations is better than 9% and 11% for intra-day and inter-day assays, respectively. The recovery of the method exceeds 88.3% for tanshinone I. The assay shows good linearity (r = 0.9998) over a relatively wide concentration range from 0.05 to 10.0 microg/mL. The method is used to determine the concentration-time profiles of tanshinone I in plasma following an intravenous injection of tanshinone I solution, and the pharmacokinetic parameters of tanshinone I are calculated for the first time by the Drug and Statistics 1.0 program. This assay is successfully applied to the determination of tanshinone I in rat plasma, and the developed method is applied to pharmacokinetic studies for the first time. PMID:18796231

  7. A sensitive LC-ESI-MS/MS method for the quantification of avobenzone in rat plasma and skin layers: Application to a topical administration study.

    PubMed

    Kim, Min Gi; Kim, Tae Hwan; Shin, Beom Soo; Kim, Min Gyu; Seok, Su Hyun; Kim, Kyu-Bong; Lee, Jong Bong; Choi, Hyeon Gwan; Lee, Young Sung; Yoo, Sun Dong

    2015-10-15

    This study describes the development of a sensitive high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the quantification of avobenzone in rat plasma and skin layers. Separations were performed on a Zorbax SB C8 column using a binary gradient mobile phase composed of acetonitrile and 0.1% formic acid in water. The assay achieved LLOQ of 0.5ng/ml for plasma, 5ng/ml for stratum corneum, and 10ng/ml for epidermis and dermis. This method was applied to a percutaneous absorption study of avobenzone in rats. At 12h following topical application of emulsion and lotion (applied amount of avobenzone 11.7mg/kg), avobenzone was found primarily in the stratum corneum (16.3-17.8%) followed by epidermis (2.0-3.4%) and dermis (0.11-0.15%). Avobenzone was not quantifiable in the plasma samples collected over a 12h sampling period. Given the excellent plasma assay sensitivity, this study provides evidence that the systemic absorption of avobenzone is insignificant, if any, after topical application.

  8. A sensitive LC-ESI-MS/MS method for the quantification of avobenzone in rat plasma and skin layers: Application to a topical administration study.

    PubMed

    Kim, Min Gi; Kim, Tae Hwan; Shin, Beom Soo; Kim, Min Gyu; Seok, Su Hyun; Kim, Kyu-Bong; Lee, Jong Bong; Choi, Hyeon Gwan; Lee, Young Sung; Yoo, Sun Dong

    2015-10-15

    This study describes the development of a sensitive high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the quantification of avobenzone in rat plasma and skin layers. Separations were performed on a Zorbax SB C8 column using a binary gradient mobile phase composed of acetonitrile and 0.1% formic acid in water. The assay achieved LLOQ of 0.5ng/ml for plasma, 5ng/ml for stratum corneum, and 10ng/ml for epidermis and dermis. This method was applied to a percutaneous absorption study of avobenzone in rats. At 12h following topical application of emulsion and lotion (applied amount of avobenzone 11.7mg/kg), avobenzone was found primarily in the stratum corneum (16.3-17.8%) followed by epidermis (2.0-3.4%) and dermis (0.11-0.15%). Avobenzone was not quantifiable in the plasma samples collected over a 12h sampling period. Given the excellent plasma assay sensitivity, this study provides evidence that the systemic absorption of avobenzone is insignificant, if any, after topical application. PMID:26409261

  9. Determination of dexmedetomidine in children's plasma by ultra-performance liquid chromatography tandem mass spectrometry and application to pharmacokinetic study.

    PubMed

    Liu, Hua-Cheng; Sun, Wei; Wang, Cheng-Yu; Ying, Wei-Yang; Zheng, Li-Dan; Zeng, Rui-Feng; Wang, Zhe; Ge, Ren-Shan

    2016-06-15

    A rapid, sensitive, and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of dexmedetomidine in children's plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2mL of acetonitrile to a 0.1mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 3.1min and the elution of dexmedetomidine was at 1.24min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring mode using the respective transitions m/z 201.3→95.1 for dexmedetomidine and m/z 204.2→98.0 for the internal standard, respectively. The calibration curve was linear over the range of 0.05-10ng/mL with a lower limit of quantitation of 0.05ng/mL. Mean recovery rate of dexmedetomidine in plasma was in the range of 86.7-89.1%. Intra-day and inter-day precision were both <11.6%. This method was successfully applied in pharmacokinetic study after commencement of 1.0μg/kg dexmedetomidine infusion in children. PMID:27179189

  10. Luminescent characteristics study of mather-type dense plasma focus and applications to short-wavelength optical pumping

    NASA Astrophysics Data System (ADS)

    Kim, K. K.

    1986-06-01

    A Mather type dense plasma focus (MDPF) system was designed, built, and tested specifically to study its luminescent characteristics and to assess its potential as a new light source of high energy, short wavelength lasers. The luminescence study of MDPF showed that the conversion efficiency from the electrical input to the optical output energies is at least 50%, up to the time the plasma compression is complete. Using the system, for the first time as an optical pump, laser activities were successfully obtained from a variety of liquid organic dyes. Diagnostic capabilities included an optical multichannel analyzer system complete with a computer control, a nitrogen pumped tunable dye laser system, a high speed streak/framing camera, a digital laser energy meter, voltage and current probes, and a computer based data acquisition system.

  11. Clinical applications of plasma based electrosurgical systems

    NASA Astrophysics Data System (ADS)

    Woloszko, Jean; Endler, Ashley; Ryan, Thomas P.; Stalder, Kenneth R.

    2013-02-01

    Over the past 18 years, several electrosurgical systems generating a low temperature plasma in an aqueous conductive solution have been commercialized for various clinical applications and have been used in over 10 million patients to date. The most popular utilizations are in arthroscopic surgery, otorhinolaryngology surgery, spine and neurosurgery, urology and wound care. These devices can be configured to bring saline to the tip and to have concomitant aspiration to remove by-products and excess fluid. By tuning the electrode geometry, waveform and fluid dynamic at the tip of the devices, tissue resection and thermal effects can be adjusted individually. This allows one to design products that can operate as precise tissue dissectors for treatment of articular cartilage or debridement of chronic wounds, as well as global tissue debulking devices providing sufficient concomitant hemostasis for applications like tonsillectomies. Effects of these plasma based electrosurgical devices on cellular biology, healing response and nociceptive receptors has also been studied in various models. This talk will include a review of the clinical applications, with product descriptions, results and introductory review of some of the research on the biological effects of these devices.

  12. Laboratory plasma probe studies

    NASA Technical Reports Server (NTRS)

    Heikkila, W. J.

    1975-01-01

    Diagnostic experiments performed in a collisionless plasma using CO2 as the working gas are described. In particular, simultaneous measurements that have been performed by means of Langmuir- and RF-probes are presented. A resonance occurring above the parallel resonance in the frequency characteristic of a two electrode system is interpreted as being due to the resonant excitation of electroacoustic waves.

  13. Determination of Acyclovir in Human Plasma Samples by HPLC Method with UV Detection: Application to Single-Dose Pharmacokinetic Study

    PubMed Central

    Zendelovska, Dragica; Simeska, Suzana; Atanasovska, Emilija; Georgievska, Kalina; Kikerkov, Igor; Labachevski, Nikola; Jakovski, Krume; Balkanov, Trajan

    2015-01-01

    BACKGROUND: The aim of this study is estimation of pharmacokinetic parameters: Cmax, tmax, t1/2, AUC0-t and AUC0-∞ with the two-way analysis of variance, single observation (ANOVA) for two preparations containing acyclovir. OBJECTIVE: In order to evaluate pharmacokinetic study of acyclovir, method for quantitative determination of acyclovir in human plasma should be simple, rapid and reproducible. Therefore, the method is developed, validated and applied for analysis of acyclovir in plasma samples obtained from healthy volunteers. MATERIAL AND METHODS: High performance liquid chromatographic (HPLC) method with UV-detection for the determination of acyclovir in human plasma is presented. This method involves protein precipitation with 20 % (V/V) perchloric acid. The chromatographic separation was accomplished on a reversed phase C8 column with a mobile phase composed of 0.1 % (V/V) triethylamine in water (pH 2.5). No internal standard is required. UV detection was set at 255 nm. The method was successfully applied for the evaluation of pharmacokinetic profiles of acyclovir tablets in 24 healthy volunteers. RESULTS: The validation results shows that proposed method is rugged, precise (RSDs for intra- and inter-day precision ranged from 1.02 to 8.37 %) and accurate (relative errors are less than 6.66 %). The calibration curve was linear in the concentration range of 0.1-2.0 µg/ml and the limit of quantification was 0.1 µg/ml. The Cmax, tmax and AUCs for the two products were not statistically different (p>0.05), suggesting that the plasma profiles generated by Zovirax were comparable to those produced by acyclovir manufactured by Jaka 80 company. CONCLUSION: Good precision, accuracy, simplicity, sensitivity and shorter time of analysis of the method makes it particularly useful for processing of multiple samples in a limited period of time for pharmacokinetic study of acyclovir. PMID:27275193

  14. Determination of nimodipine in human plasma by HPLC-ESI-MS and its application to a bioequivalence study.

    PubMed

    Zhao, Ying; Zhai, Desheng; Chen, Xijing; Yu, Qiaoling; He, Hui; Sun, Ya; Gao, Zidong; Wang, Lei; Wang, Huanhuan; Han, De'en; Ji, Hui

    2010-02-01

    A simple, specific, and precise liquid chromatographic-electrospray ionization mass spectrometric (LC-ESI-MS) method has been developed for determination of nimodipine concentration in human plasma. The method involves the addition of 200 microL of saturated sodium bicarbonate (NaHCO(3)) solution to plasma to improve the extraction recovery, liquid-liquid extraction of nimodipine from plasma samples with anhydrous diethyl ether, simple reversed-phase chromatography, and ESI mass spectrometric detection in negative ion selected ion monitoring mode (SIM) using target [M-] ions at m/z 417 and m/z 359 for nimodipine and nitrendipine (internal standard, IS), respectively. A complete analytical run was achieved within 3.5 min. The limit of quantification was 0.5 ng/mL. The method was validated within a linear range of 0.5-100 ng/mL. The correlation coefficient for the calibration regression line was 0.9995 or better. Intra- and inter-batch accuracy and precision were acceptable. Analyte was stable in a battery of stability studies. The method has been successfully used in a bioequivalence study. PMID:20109281

  15. Large area cold plasma applicator for decontamination

    NASA Astrophysics Data System (ADS)

    Konesky, G. A.

    2008-04-01

    Cold plasma applicators have been used in the Medical community for several years for uses ranging from hemostasis ("stop bleeding") to tumor removal. An added benefit of this technology is enhanced wound healing by the destruction of infectious microbial agents without damaging healthy tissue. The beam is typically one millimeter to less than a centimeter in diameter. This technology has been adapted and expanded to large area applicators of potentially a square meter or more. Decontamination applications include both biological and chemical agents, and assisting in the removal of radiological agents, with minimal or no damage to the contaminated substrate material. Linear and planar multiemitter array plasma applicator design and operation is discussed.

  16. Formation and emission characteristics of CN molecules in laser induced low pressure He plasma and its applications to N analysis in coal and fossilization study.

    PubMed

    Lahna, Kurnia; Idroes, Rinaldi; Idris, Nasrullah; Abdulmadjid, Syahrun Nur; Kurniawan, Koo Hendrik; Tjia, May On; Pardede, Marincan; Kagawa, Kiichiro

    2016-03-01

    Presented in this paper are the results of an experimental study on the laser induced plasma emission of a number of CN free samples (urea, sucrose) with 40 mJ pulse energy using He and N₂ ambient gases. It is shown that the CN emission has its exclusive sources in the molecules produced as the result of chemical bonding either between the ablated C and N ions in the He plasma or between the ablated C and dissociated N from the N₂ ambient gas. The emission intensities in both cases are found to have the highest values at the low gas pressure of 2 kPa. The emission in He gas is shown to exhibit the typical characteristics related to a shockwave generated excitation mechanism. The experiments using He ambient gas further demonstrate the feasible laser-induced breakdown spectroscopy application to quantitative and sensitive N analysis of coal and promising application for practical in situ carbon dating of fossils.

  17. Plasma Sources for Medical Applications - A Comparison of Spot Like Plasmas and Large Area Plasmas

    NASA Astrophysics Data System (ADS)

    Weltmann, Klaus-Dieter

    2015-09-01

    Plasma applications in life science are currently emerging worldwide. Whereas today's commercially available plasma surgical technologies such as argon plasma coagulation (APC) or ablation are mainly based on lethal plasma effects on living systems, the newly emerging therapeutic applications will be based on selective, at least partially non-lethal, possibly stimulating plasma effects on living cells and tissue. Promising results could be obtained by different research groups worldwide revealing a huge potential for the application of low temperature atmospheric pressure plasma in fields such as tissue engineering, healing of chronic wounds, treatment of skin diseases, tumor treatment based on specific induction of apoptotic processes, inhibition of biofilm formation and direct action on biofilms or treatment of dental diseases. The development of suitable and reliable plasma sources for the different therapies requires an in-depth knowledge of their physics, chemistry and parameters. Therefore much basic research still needs to be conducted to minimize risk and to provide a scientific fundament for new plasma-based medical therapies. It is essential to perform a comprehensive assessment of physical and biological experiments to clarify minimum standards for plasma sources for applications in life science and for comparison of different sources. One result is the DIN-SPEC 91315, which is now open for further improvements. This contribution intends to give an overview on the status of commercial cold plasma sources as well as cold plasma sources still under development for medical use. It will discuss needs, prospects and approaches for the characterization of plasmas from different points of view. Regarding the manageability in everyday medical life, atmospheric pressure plasma jets (APPJ) and dielectric barrier discharges (DBD) are of special interest. A comprehensive risk-benefit assessment including the state of the art of commercial sources for medical use

  18. Determination and validation of chikusetsusaponin IVa in rat plasma by UPLC-MS/MS and its application to pharmacokinetic study.

    PubMed

    Wang, Ying; Liu, Shi-Ping; Guo, Mei-Hua; Wang, Zhuo

    2016-09-01

    A novel, sensitive and rapid ultra-performance liquid chromatography-tandem mass spectrometric method for the quantification of chikusetsusaponin IVa (CHS-IVa) in rat plasma was established and validated. Plasma samples were pre-treated by precipitation of protein with acetonitrile and chromatographed on a Waters Symmetry C18 analytical column (4.6 × 50 mm, i.d., 3.5 μm) using a mobile phase consisting of methanol and water containing 0.05% formic acid (55:45, v/v) at a flow rate of 0.4 mL/min. The deprotonated molecular ions [M - H](-) were employed in electrospray negative ionization mode and selected reaction monitoring transitions were performed for detection. The calibration curves exhibited good linearity (r > 0.99) over the range of 0.5-1000 ng/mL for CHS-IVa. The recoveries of CHS-IVa were >92.5% and exhibited no severe matrix effect. This method was successfully applied in the pharmacokinetic study of CHS-IVa in rats. For oral administration, the plasma concentrations of CHS-IVa increased to a peak value at 0.35 ± 0.14 h, followed by a gradual decrease to the lower limit of quantitation in 24 h. For intravenous administration, the plasma concentrations of CHS-IVa decreased quickly (t1/2 , 1.59 ± 0.25 h). The absolute bioavailability of CHS-IVa in rats was 8.63%. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Accuracy assessment on the analysis of unbound drug in plasma by comparing traditional centrifugal ultrafiltration with hollow fiber centrifugal ultrafiltration and application in pharmacokinetic study.

    PubMed

    Zhang, Lin; Zhang, Zhi-Qing; Dong, Wei-Chong; Jing, Shao-Jun; Zhang, Jin-Feng; Jiang, Ye

    2013-11-29

    In present study, accuracy assessment on the analysis of unbound drug in plasma was made by comparing traditional centrifugal ultrafiltration (CF-UF) with hollow fiber centrifugal ultrafiltration (HFCF-UF). We used metformin (MET) as a model drug and studied the influence of centrifugal time, plasma condition and freeze-thaw circle times on the ultrafiltrate volume and related effect on the measurement of MET. Our results demonstrated that ultrafiltrate volume was a crucial factor which influenced measurement accuracy of unbound drug in plasma. For traditional CF-UF, the ultrafiltrate volume cannot be well-controlled due to a series of factors. Compared with traditional CF-UF, the ultrafiltrate volume by HFCF-UF can be easily controlled by the inner capacity of the U-shaped hollow fiber inserted into the sample under enough centrifugal force and centrifugal time, which contributes to a more accurate measurement. Moreover, the developed HFCF-UF method achieved a successful application in real plasma samples and exhibited several advantages including high precision, extremely low detection limit and perfect recovery. The HFCF-UF method offers the advantage of highly satisfactory performance in addition to being simple and fast in pretreatment, with these characteristics being consistent with the practicability requirements in current scientific research.

  20. Application of Dusty Plasmas for Space

    NASA Astrophysics Data System (ADS)

    Bhavasar, Hemang; Ahuja, Smariti

    plasmas, dust particles are actually grown in the discharge from the reactive gases used to form the plasmas. Perhaps the most intriguing aspect of dusty plasmas is that the particles can be directly imaged and their dynamic behavior recorded as digital images. This is accomplished by laser light scattering from the particles. Since the particle mass is relatively high, their dynamical timescales are much longer than that of the ions or electrons. Dusty plasmas has a broad range of applications including interplanetary space dust, comets, planetary rings, dusty surfaces in space, and aerosols in the atmosphere.

  1. UPLC-MS-MS Method for the Determination of Vilazodone in Human Plasma: Application to a Pharmacokinetic Study.

    PubMed

    El-Bagary, Ramzia; Hashem, Hanaa; Fouad, Marwa; Tarek, Sally

    2016-09-01

    A sensitive, rapid and simple liquid chromatographic-electrospray ionization tandem mass spectrometric (LC-ESI-MS-MS) method was developed for the quantitative determination of vilazodone in human plasma and for the study of the pharmacokinetic behavior of vilazodone in healthy Egyptian volunteers. With escitalopram as internal standard (IS), liquid-liquid extraction was used for the purification and preconcentration of analytes from human plasma matrix using diethyl ether. The separation was performed on an Acquity UPLC BEH shield RP C18 column (1.7 µm, 2.1 × 150 mm). Isocratic elution was applied using methanol-0.2% formic acid (90:10, v/v). Detection was performed on a triple-quadrupole tandem mass spectrometer with multiple reaction monitoring mode via an electrospray ionization source at m/z 442.21 → 155.23 for vilazodone and m/z 325.14 → 109.2 for escitalopram. Linear calibration curves were obtained over the range of 1-200 ng/mL with the lower limit of quantification at 1 ng/mL. The intra- and inter-day precision showed relative standard deviation ≤3.3%. The total run time was 1.5 min. This method was successfully applied for clinical pharmacokinetic investigation, and a preliminary metabolic study was also carried out. PMID:27209054

  2. Simultaneous Quantification of Baricitinib and Methotrexate in Rat Plasma by LC-MS/MS: Application to a Pharmacokinetic Study

    PubMed Central

    Veeraraghavan, Sridhar; Thappali, Satheeshmanikandan R. S.; Viswanadha, Srikant; Vakkalanka, Swaroop; Rangaswamy, Manivannan

    2016-01-01

    Efficacy assessments using a combination of baricitinib and methotrexate necessitate the development of an analytical method for the determination of both drugs in plasma with precision. A high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of baricitinib and methotrexate in rat plasma. Extraction of baricitinib, methotrexate, and tolbutamide (internal standard; IS) from 50 µL of rat plasma was carried out by protein precipitation with methanol. Chromatographic separation of the analytes was performed on the YMC pack ODS AM (150 mm × 4.6 mm, 5 µm) column under gradient conditions with methanol: 2.0 mM ammonium acetate buffer as the mobile phases at a flow rate of 1 mL/min. The precursor ion and product ion transition for both analytes and IS were monitored on a triple quadrupole mass spectrometer, operated with selective reaction monitoring in positive ionization mode. The method was validated over a concentration range of 0.5–250.00 ng/mL for baricitinib and methotrexate. Mean extraction recoveries for baricitinib, methotrexate, and IS of 86.8%, 89.4%, and 91.8% were consistent across low, medium, and high QC levels, respectively. Precision and accuracy at low, medium, and high quality control levels were less than 15% across the analytes. Benchtop, wet, freeze-thaw, and long-term stability were evaluated for both of the analytes. The analytical method was applied to support the pharmacokinetic study of simultaneous estimation of baricitinib and methotrexate in Wistar rats. Assay reproducibility was demonstrated by reanalysis of 18 incurred samples PMID:27222609

  3. Simultaneous Quantification of Baricitinib and Methotrexate in Rat Plasma by LC-MS/MS: Application to a Pharmacokinetic Study.

    PubMed

    Veeraraghavan, Sridhar; Thappali, Satheeshmanikandan R S; Viswanadha, Srikant; Vakkalanka, Swaroop; Rangaswamy, Manivannan

    2016-01-01

    Efficacy assessments using a combination of baricitinib and methotrexate necessitate the development of an analytical method for the determination of both drugs in plasma with precision. A high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of baricitinib and methotrexate in rat plasma. Extraction of baricitinib, methotrexate, and tolbutamide (internal standard; IS) from 50 µL of rat plasma was carried out by protein precipitation with methanol. Chromatographic separation of the analytes was performed on the YMC pack ODS AM (150 mm × 4.6 mm, 5 µm) column under gradient conditions with methanol: 2.0 mM ammonium acetate buffer as the mobile phases at a flow rate of 1 mL/min. The precursor ion and product ion transition for both analytes and IS were monitored on a triple quadrupole mass spectrometer, operated with selective reaction monitoring in positive ionization mode. The method was validated over a concentration range of 0.5-250.00 ng/mL for baricitinib and methotrexate. Mean extraction recoveries for baricitinib, methotrexate, and IS of 86.8%, 89.4%, and 91.8% were consistent across low, medium, and high QC levels, respectively. Precision and accuracy at low, medium, and high quality control levels were less than 15% across the analytes. Benchtop, wet, freeze-thaw, and long-term stability were evaluated for both of the analytes. The analytical method was applied to support the pharmacokinetic study of simultaneous estimation of baricitinib and methotrexate in Wistar rats. Assay reproducibility was demonstrated by reanalysis of 18 incurred samples.

  4. Simultaneous quantification of ruxolitinib and nilotinib in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

    PubMed

    Veeraraghavan, Sridhar; Thappali, Satheeshmanikandan; Viswanadha, Srikant; Chennupati, Sandhyarani; Nalla, Santhoshkumar; Golla, Manikantakumar; Vakkalanka, Swaroopkumar; Rangasamy, Manivannan

    2014-06-01

    Efficacy assessments using a combination of ruxolitinib and nilotinib necessitate the development of a high precision analytical method for determination of both drugs in plasma. A high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of ruxolitinib and nilotinib in rat plasma. Extraction of ruxolitinib, nilotinib and dasatinib (internal standard; IS) from 50μl rat plasma was carried out by protein precipitation with methanol. Chromatographic separation of analytes was performed on YMC pack ODS AM (150mm×4.6mm, 5μm) column under gradient conditions with acetonitrile:2.0mM ammonium acetate buffer as the mobile phase at a flow rate of 1ml/min. Precursor ion and product ion transition for both analytes and IS were monitored on a triple quadrupole mass spectrometer, operated in the selective reaction monitoring with positive ionization mode. Method was validated over a concentration range of 0.16-247ng/ml for ruxolitinib and 0.86-219ng/ml for nilotinib. Mean extraction recovery for ruxolitinib, nilotinib, and IS of 99.6%, 97.6% and 90.3% were consistent across low, medium, and high QC levels. Precision and accuracy at low, medium and high quality control levels were less than 15% across analytes. Bench top, wet, freeze-thaw and long term stability were evaluated for both analytes. The analytical method was applied to support a pharmacokinetic study of simultaneous estimation of ruxolitinib and nilotinib in Wistar rat. Assay reproducibility was demonstrated by re-analysis of 18 incurred samples.

  5. Rapid determination of apixaban concentration in human plasma by liquid chromatography/tandem mass spectrometry: application to pharmacokinetic study.

    PubMed

    Delavenne, Xavier; Mismetti, Patrick; Basset, Thierry

    2013-05-01

    We described the development and full validation of a rapid, high throughput sensible and accurate LC method using tandem mass spectrometry detection for determining apixaban concentration with [(¹³C, ²H₇]-apixaban as internal standard in human plasma. Plasma pretreatment involved a one-step protein precipitation with methanol. The separation was performed by reverse-phase chromatography on a Luna MercuryMS C18 column (20 mm × 4 mm × 3 μm) column. The multiple reaction monitoring transitions used for quantification were m/z 460.20→443.27 and 460.20→198.99 for apixaban, 468.22→451.30 for [(¹³C, ²H₇]-apixaban in the electrospray positive ionization mode. The method was linear over the concentration range of 5-500 μg/L. The intra- and inter-day precision values were below 14% and accuracy was from 90.0 to 105.8% at all quality control levels. Sample analysis time was less than 10 min including sample preparation. The present method was successfully applied to a pharmacokinetic study following oral administration of apixaban. PMID:23499913

  6. Simultaneous quantification of picfeltarraenins IA and IB in rat plasma by UPLC-MS/MS: Application to a pharmacokinetic study.

    PubMed

    He, Xin; Zhang, Yingjie; Gao, Hang; Li, Keyan; Zhang, Yazhuo; Sun, Limin; Tao, Guizhou

    2016-02-20

    A simple and rapid quantitative UPLC-MS/MS method for simultaneous determination of picfeltarraenins IA and IB in rat plasma was developed and validated in accordance with the US FDA Bioanalytical Guidance (2001). Analytes were extracted from rat plasma by using methanol and separated on Agilent ZORBAX SB-C18 (50mm×2.1mm, 1.8μm) column by using a mobile phase composed of methanol and water (70:30, v/v). Eluents were monitored by ESI tandem mass spectrometry detection with SRM mode using ion transitions m/z 785.4→639.5, m/z 815.5→669.5, and m/z 763.5→455.3 for picfeltarraenin IA, picfeltarraenin IB, and internal standard, respectively. The method was validated over the linear range of 11.5-1150ng/mL and 13.0-1300ng/mL. The developed analytical method was applied to support a pharmacokinetic study on simultaneous estimation of picfeltarraenins IA and IB in rats.

  7. Highly sensitive LC-MS/MS method for determination of galantamine in rat plasma: application to pharmacokinetic studies in rats.

    PubMed

    Suresh, P S; Mullangi, Ramesh; Sukumaran, Sathesh Kumar

    2014-12-01

    A rapid and highly sensitive assay method has been developed and validated for the estimation of galantamine (GLM) in rat plasma using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. The assay procedure involves a simple liquid-liquid extraction of GLM and phenacetin (internal standard, IS) from rat plasma using acetonitrile. Chromatographic separation was achieved with 0.2% formic acid:acetonitrile (50:50, v/v) at a flow rate of 0.60 mL/min on an Atlantis dC18 column with a total run time 2.5 min. The MS/MS ion transitions monitored were 288.10 → 213.10 for GLM and 180.10 → 110.10 for IS. Method validation was performed as per United States Food and Drug Administration guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.12 ng/mL and linearity was observed from 0.12 to 525 ng/mL. The intra- and inter-day precision were in the ranges of 4.73-11.7 and 5.83-8.64%, respectively. This novel method has been applied to a pharmacokinetic study in rats.

  8. Simultaneous determination of amoxicillin and ambroxol in human plasma by LC-MS/MS: validation and application to pharmacokinetic study.

    PubMed

    Wen, Aidong; Hang, Taijun; Chen, Suning; Wang, Zhirui; Ding, Likun; Tian, Yun; Zhang, Meng; Xu, Xinxin

    2008-11-01

    A rapid, simple and sensitive LC-MS/MS method was developed for simultaneous determination of amoxicillin and ambroxol in human plasma using clenbuterol as internal standard (IS). The plasma samples were subjected to a simple protein precipitation with methanol. Separation was achieved on a Lichrospher C(18) column (150 mm x 4.6mm ID, dp 5 microm) using methanol (containing 0.2% of formic acid) and water (containing 0.2% of formic acid) as a mobile phase by gradient elution at a flow rate of 1.0 mL/min. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring (MRM) mode by monitoring the ion transitions from m/z 365.9-->348.9 (amoxicillin), m/z 378.9-->263.6 (ambroxol) and m/z 277.0-->203.0 (IS). Calibration curves were linear in the concentration range of 5-20,000 ng/mL for amoxicillin, and 1-200 ng/mL for ambroxol, with the intra- and inter-run precisions of <9% and the accuracies of 100+/-7%. The method has been validated and applied to pharmacokinetic studies of compound amoxicillin and ambroxol hydrochloride tablets in healthy Chinese volunteers.

  9. Determination of rutin in rat plasma by ultra performance liquid chromatography tandem mass spectrometry and application to pharmacokinetic study.

    PubMed

    Chen, Mengchun; Zhang, Xiaoqian; Wang, Hao; Lin, Baoli; Wang, Shuanghu; Hu, Guoxin

    2015-04-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS) method for the determination of rutin in rat plasma was developed and validated. After addition of tolbutamide as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. The chromatographic separation was performed on an Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm particle size), using acetonitrile-0.1% formic acid as the mobile phase with gradient elution, delivered at a flow-rate of 0.4 mL/min. Mass spectrometric analysis was performed using a XEVO TQD mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 610.91→302.98 and m/z 271.2→155.1 were used to quantify for rutin and tolbutamide, respectively. This assay method has been fully validated in terms of specificity, linearity, recovery and matrix effect, accuracy, precision and stability. Calibration curves were linear in the concentration ranges of 25-2000 ng/mL for rutin. Only 3 min was needed for an analytical run. This developed method was successfully used for determination of rutin in rat plasma for pharmacokinetic study.

  10. Reflectometric measurement of plasma imaging and applications

    NASA Astrophysics Data System (ADS)

    Mase, A.; Ito, N.; Oda, M.; Komada, Y.; Nagae, D.; Zhang, D.; Kogi, Y.; Tobimatsu, S.; Maruyama, T.; Shimazu, H.; Sakata, E.; Sakai, F.; Kuwahara, D.; Yoshinaga, T.; Tokuzawa, T.; Nagayama, Y.; Kawahata, K.; Yamaguchi, S.; Tsuji-Iio, S.; Domier, C. W.; Luhmann, N. C., Jr.; Park, H. K.; Yun, G.; Lee, W.; Padhi, S.; Kim, K. W.

    2012-01-01

    Progress in microwave and millimeter-wave technologies has made possible advanced diagnostics for application to various fields, such as, plasma diagnostics, radio astronomy, alien substance detection, airborne and spaceborne imaging radars called as synthetic aperture radars, living body measurements. Transmission, reflection, scattering, and radiation processes of electromagnetic waves are utilized as diagnostic tools. In this report we focus on the reflectometric measurements and applications to biological signals (vital signal detection and breast cancer detection) as well as plasma diagnostics, specifically by use of imaging technique and ultra-wideband radar technique.

  11. Determination of levocetirizine in human plasma by LC-MS-MS: validation and application in a pharmacokinetic study.

    PubMed

    Wichitnithad, Wisut; Jithavech, Ponsiree; Sanphanya, Kingkan; Vicheantawatchai, Petploy; Rojsitthisak, Pornchai

    2015-01-01

    A fast and simple sample cleanup approach for levocetirizine in human was developed using protein precipitation coupled with LC-MS-MS. Samples were treated with 6% trichloroacetic acid in water prior to LC-MS-MS analysis. Chromatographic separation was performed on a reverse phase column with an isocratic mobile phase of acetonitrile and 10 mM ammonium formate pH 3.5 (80:20, v/v) at a flow rate of 1.0 mL/min. The run time was 3.5 min. Mass parameters were optimized to monitor transitions at m/z [M+H](+) 389.0→201.0 for levocetirizine and m/z [M+H](+) 375.3→201.0 for hydroxyzine as internal standard. The lower limit of quantification and the dynamic range were 1.00 and 1.00-500 ng/mL, respectively. Linearity was good for intraday and interday validations (r(2) ≥ 0.995). The mean recoveries were 59 and 69% for levocetirizine and hydroxyzine, respectively. Matrix effect was acceptable with %CV < 15. Hemolytic effect was negligible. Levocetirizine was stable in human plasma for 27 h at room temperature (25°C), for 16 weeks frozen at -70°C, 4 weeks frozen at -20°C, for 24 h in an autosampler at 15°C and for three freeze/thaw cycles. The validated method was applied in a pharmacokinetic study to determine the concentration of levocetirizine in plasma samples. The study provides a fast and simple bioanalytical method for routine analysis and may be particularly useful for bioequivalence studies. PMID:26084706

  12. Physics and medical applications of cold atmospheric plasma

    NASA Astrophysics Data System (ADS)

    Keidar, Michael

    2013-09-01

    Recent progress in atmospheric plasmas led to the creation of cold plasmas with ion temperature close to room temperature. Varieties of novel plasma diagnostic techniques were applied in a quest to understand physics of cold plasmas. In particular it was established that the streamer head charge is about 108 electrons, the electrical field in the head vicinity is about 107 V/m, and the electron density of the streamer column is about 1019 m3. We have demonstrated the efficacy of cold plasma in a pre-clinical model of various cancer types (lung, bladder, breast, head, neck, brain and skin). Both in-vitro andin-vivo studies revealed that cold plasmas selectively kill cancer cells. We showed that: (a) cold plasma application selectively eradicates cancer cells in vitro without damaging normal cells. (b) Significantly reduced tumor size in vivo. Cold plasma treatment led to tumor ablation with neighbouring tumors unaffected. These experiments were performed on more than 10 mice with the same outcome. We found that tumors of about 5mm in diameter were ablated after 2 min of single time plasma treatment. The two best known cold plasma effects, plasma-induced apoptosis and the decrease of cell migration velocity can have important implications in cancer treatment by localizing the affected area of the tissue and by decreasing metastasic development. In addition, cold plasma treatment has affected the cell cycle of cancer cells. In particular, cold plasmainduces a 2-fold increase in cells at the G2/M-checkpoint in both papilloma and carcinoma cells at ~24 hours after treatment, while normal epithelial cells (WTK) did not show significant differences. It was shown that reactive oxygen species metabolism and oxidative stress responsive genes are deregulated. We investigated the production of reactive oxygen species (ROS) with cold plasma treatment as a potential mechanism for the tumor ablation observed.

  13. HPLC method for the determination of rosiglitazone in human plasma and its application in a clinical pharmacokinetic study.

    PubMed

    Mamidi, Rao N V S; Chaluvadi, Madhusudana R; Benjamin, Biju; Ramesh, Mullangi; Katneni, Kasiram; Babu, Aravinda P; Bhanduri, Jaydip; Rao, Naidu M U; Rajagopalan, Ramanujam

    2002-01-01

    Rosiglitazone (CAS 155141-29-0, Avandia) is a novel insulin sensitizer used in the treatment of type 2 diabetes. A sensitive high performance liquid chromatography (HPLC) method for its determination in human plasma using fluorescence detection (excitation: 247 nm, emission: 367 nm) with a suitable internal standard (I. S.) is described. Ethyl acetate was used as extraction solvent. A mobile phase consisting of phosphate buffer, acetonitrile and methanol was used at a flow rate of 1.0 ml/min on a C18 column. The absolute recovery was > 90% and the lower limit of quantitation was 5 ng/ml. The intra- and inter-day relative standard deviations ranged from 0.58-6.69% and 0.82-6.63%, respectively. The method described is simple, economical, precise and accurate and has been successfully applied in a pharmacokinetic study conducted in healthy human volunteers. PMID:12189780

  14. Determination of chlorpheniramine in human plasma by HPLC-ESI-MS/MS: application to a dexchlorpheniramine comparative bioavailability study.

    PubMed

    Moreno, Ronilson Agnaldo; Oliveira-Silva, Diogo; Sverdloff, Carlos Eduardo; Borges, Bruno Carter; Rebelo Galvinas, Paulo Alexandre; Astigarraga, Rafael Barrientos; Borges, Ney Carter

    2010-07-01

    In the present study a fast, sensitive and robust validated method to quantify chlorpheniramine in human plasma using brompheniramine as internal standard (IS) is described. The analyte and the IS were extracted from plasma by LLE (diethyl ether-dichloromethane, 80:20, v/v) and analyzed by HPLC-ESI-MS/MS. Chromatographic separation was performed using a gradient of methanol from 35 to 90% with 2.5 mm NH(4)OH on a Gemini Phenomenex C(8) 5 microm column (50 x 4.6 mm i.d.) in 5.0 min/run. The method fitted to a linear calibration curve (0.05-10 ng/mL, R > 0.9991). The precision (%CV) and accuracy ranged, respectively: intra-batch from 1.5 to 6.8% and 99.1 to 106.6%, and inter-batch from 2.4 to 9.0%, and 99.9 to 103.1%. The validated bioanalytical procedure was used to assess the comparative bioavailability in healthy volunteers of two dexchlorpheniramine 2.0 mg tablet formulations (test dexchlorpheniramine, Eurofarma, and reference Celestamine, Schering-Plough). The study was conducted using an open, randomized, two-period crossover design with a 2 week washout interval. Since the 90% confidence interval for C(max) and AUC ratios were all within the 80-125% interval proposed by ANVISA and FDA, it was concluded that test and reference formulations are bioequivalent concerning the rate and the extent of absorption.

  15. Quantitation of bentysrepinine (Y101) in rat plasma by liquid chromatography tandem mass spectrometry: application to pharmacokinetic study.

    PubMed

    Fan, Huirong; Li, Ruixing; Gu, Yuan; Si, Duanyun; Liu, Changxiao

    2012-03-15

    A simple, accurate and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for quantitation of bentysrepinine (Y101) in rat plasma. After the addition of diphenhydramine (internal standard, IS), plasma samples were pretreated by protein precipitation. Chromatographic separation was carried out on an Atlantis(®) analytical column (4.6 mm × 100 mm, 5 μm, Waters) with methanol: 20 mM ammonium formate consisting of 1.0% formic acid (65:35, v/v) as the mobile phase at an isocratic flow rate of 0.4 mL/min for 7.5 min. The multiple reaction monitoring (MRM) transitions were performed at m/z 490.2→339.5 for Y101 and m/z 256.0→167.0 for IS on a SCIEX API 4000 mass spectrometer in the positive ion mode with electrospray ionization (ESI) source. Good linearity was achieved over the concentration range of 1-2500 ng/mL. The intra- and inter-day precisions were less than 8.3%, and the accuracy ranged from -4.0% to 2.8%. Y101 was stable during the analysis and the storage period. The pharmacokinetic profiles of Y101 at three dose levels were successfully studied for the first time in rats by this method. After single intra-gastric administration of Y101 at the doses of 25, 50 and 100 mg/kg, C(max) and AUC(0-t) were proportional to the doses given. PMID:22366283

  16. A sensitive LC-MS/MS method for quantifying capsaicin and dihydrocapsaicin in rabbit plasma and tissue: application to a pharmacokinetic study.

    PubMed

    Wang, Dimin; Meng, Fanhua; Yu, Lin; Sun, Lu; Sun, Lili; Guo, Jifen

    2015-04-01

    Prescription and nonprescription products for topical management of pain, including cream, lotion and patch forms, contain capsaicin (CAP) and dihydrocapsaicin (DHC). There are few in vivo studies on absorption, bioavailability and disposition of CAP and DHC. We established a sensitive and rapid LC-MS/MS assay to determine CAP and DHC levels in rabbit plasma and tissue. Bio-samples prepared by liquid-liquid extraction using n-hexane-dichloromethane-isopropanol (100: 50: 5, v/v/v) mixture were separated by isocratic chromatography with an Extend C18 column. The mobile phase was acetonitrile-water-formic acid (70: 30: 0.1, v/v/v). The method was linear from 0.125 to 50 ng/mL for a 100 μL bio-sample, and the lower quantification limit was 0.125 ng/mL. Total run time to analyze each sample was 3.5 min. We used this validated method to study pharmacokinetics and tissue distribution of CAP gel administered topically to rabbits. A very small amount of CAP and DHC was absorbed into the systemic circulation. The highest plasma concentration was 2.39 ng/mL, and the mean peak plasma concentration value after 12 h of CAP gel application was 1.68 ng/mL. Drug concentration in treated skin was relatively high, with low concentration in other tissues. Thus, topical CAP gel had strong local effects and weaker systemic effects.

  17. Current new applications of laser plasmas

    SciTech Connect

    Hauer, A.A.; Forslund, D.W.; McKinstrie, C.J.; Wark, J.S.; Hargis, P.J. Jr.; Hamil, R.A.; Kindel, J.M.

    1988-09-01

    This report describes several new applications of laser-produced plasmas that have arisen in the last few years. Most of the applications have been an outgrowth of the active research in laser/matter interaction inspired by the pursuit of laser fusion. Unusual characteristics of high-intensity laser/matter interaction, such as intense x-ray and particle emission, were noticed early in the field and are now being employed in a significant variety of applications outside the fusion filed. Applications range from biology to materials science to pulsed-power control and particle accelerators. 92 refs., 23 figs., 4 tabs.

  18. Suspension Plasma Spraying: Process Characteristics and Applications

    NASA Astrophysics Data System (ADS)

    Vaßen, Robert; Kaßner, Holger; Mauer, Georg; Stöver, Detlev

    2010-01-01

    Suspension plasma spraying (SPS) offers the manufacture of unique microstructures which are not possible with conventional powdery feedstock. Due to the considerably smaller size of the droplets and also the further fragmentation of these in the plasma jet, the attainable microstructural features like splat and pore sizes can be downsized to the nanometer range. Our present understanding of the deposition process including injection, suspension plasma plume interaction, and deposition will be outlined. The drawn conclusions are based on analysis of the coating microstructures in combination with particle temperature and velocity measurements as well as enthalpy probe investigations. The last measurements with the water cooled stagnation probe gives valuable information on the interaction of the carrier fluid with the plasma plume. Meanwhile, different areas of application of SPS coatings are known. In this paper, the focus will be on coatings for energy systems. Thermal barrier coatings (TBCs) for modern gas turbines are one important application field. SPS coatings offer the manufacture of strain-tolerant, segmented TBCs with low thermal conductivity. In addition, highly reflective coatings, which reduce the thermal load of the parts from radiation, can be produced. Further applications of SPS coatings as cathode layers in solid oxide fuel cells (SOFC) and for photovoltaic (PV) applications will be presented.

  19. APPLICATION ANALYSIS REPORT: RETECH PLASMA CENTRIFUGAL FURNACE

    EPA Science Inventory

    This document is an evaluation of the performance of the Retech, Inc. Plasma Centrifugal Furnace (PCF) and its applicability as a treatment for soils contaminated with organic and/or inorganic compounds. Both the technical and economic aspectsof the technology were examined. A...

  20. Laboratory and Space Plasma Studies

    NASA Astrophysics Data System (ADS)

    Hyman, Ellis

    1996-08-01

    The work performed by Science Applications International Corporation (SAIC), encompasses a wide range of topics in experimental, computational, and analytical laboratory and space plasma physics. The accomplishments described in this report have been in support of the programs of the Laser Plasma Branch (Code 6730) and other segments of the Plasma Physics Division at the Naval Research Laboratory (NRL) and cover the period 27 September 1993 to August 1, 1996. SAIC's efforts have been supported by sub-contracts or consulting agreements with Pulse Sciences, Inc., Clark Richardson, and Biskup Consulting Engineers, Pharos Technical Enterprises, Plex Corporation, Cornell University, Stevens Institute of Technology, the University of Connecticut, Plasma Materials and Technologies, Inc., and GaSonics International, Inc. In the following discussions section we will describe each of the topics investigated and the results obtained. Much of the research work has resulted in journal publications and NRL Memorandum Reports in which the investigation is described in detail. These reports are included as Appendices to this Final Report.

  1. Dust Accelerators And Their Applications In High-Temperature Plasmas

    SciTech Connect

    Ticos, Catalin M.; Wang Zhehui

    2011-06-01

    The perennial presence of dust in high-temperature plasma and fusion devices has been firmly established. Dust inventory must be controlled, in particular in the next-generation steady-state fusion machines like ITER, as it can pose significant safety hazards and potentially interfere with fusion energy production. Although much effort has been devoted to getting rid of the dust nuisance, there are instances where a controlled use of dust can be beneficial. We have recognized a number of dust-accelerators applications in magnetic fusion, including in plasma diagnostics, in studying dust-plasma interactions, and more recently in edge localized mode (ELM)'s pacing. With the applications in mind, we will compare various acceleration methods, including electrostatic, gas-drag, and plasma-drag acceleration. We will also describe laboratory experiments and results on dust acceleration.

  2. Dust accelerators and their applications in high-temperature plasmas

    SciTech Connect

    Wang, Zhehui; Ticos, Catakin M

    2010-01-01

    The perennial presence of dust in high-temperature plasma and fusion devices has been firmly established. Dust inventory must be controlled, in particular in the next-generation steady-state fusion machines like ITER, as it can pose significant safety hazards and potentially interfere with fusion energy production. Much effort has been devoted to gening rid of the dust nuisance. We have recognized a number of dust-accelerators applications in magnetic fusion, including in plasma diagnostics, in studying dust-plasma interactions, and more recently in edge localized mode (ELM)'s pacing. With the applications in mind, we will compare various acceleration methods, including electrostatic, gas-drag, and plasma-drag acceleration. We will also describe laboratory experiments and results on dust acceleration.

  3. Determination of geniposide in adjuvant arthritis rat plasma by ultra-high performance liquid chromatography tandem mass spectrometry method and its application to oral bioavailability and plasma protein binding ability studies.

    PubMed

    Chen, Jian; Wu, Hong; Xu, Guo-Bing; Dai, Miao-Miao; Hu, Shun-Li; Sun, Liang-Liang; Wang, Wei; Wang, Rong; Li, Shu-Pin; Li, Guo-Qiang

    2015-04-10

    A specific, sensitive and high throughput ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometric method (UHPLC-ESI-MS/MS) was established and validated to assay geniposide (GE), a promising anti-inflammatory drug, in adjuvant arthritis rat plasma: application to pharmacokinetic and oral bioavailability studies and plasma protein binding ability. Plasma samples were processed by de-proteinised with ice-cold methanol and separated on an ACQUITY UPLC™ HSS C18 column (100 mm × 2.1mm i.d., 1.8 μm particle size) at a gradient flow rate of 0.2 mL/min using acetonitrile-0.1% formic acid in water as mobile phase, and the total run time was 9 min. Mass detection was performed in selected reaction monitoring (SRM) mode with negative electro-spray ionization includes the addition of paeoniflorin (Pae) as an internal standard (IS). The mass transition ion-pair was followed as m/z 387.4 → 122.4 for GE and m/z 479.4 → 449.0 for IS. The calibration curves were linear over the concentration range of 2-50,000 ng/mL with lower limit of quantification of 2 ng/mL. The intra-day and inter-day precisions (RSD, %) of the assay were less than 8.4%, and the accuracy was within ± 6.4% in terms of relative error (RE). Extraction recovery, matrix effect and stability were satisfactory in adjuvant arthritis rat plasma. The UHPLC-ESI-MS/MS method was successfully applied to a pharmacokinetic study of GE after oral administration of depurated GE at 33, 66, 132 mg/kg and intravenous injection at 33, 66, 132 mg/kg in adjuvant arthritis (AA) rats. In addition, it was found that GE has rapid absorption and elimination, low absolute bioavailability, high plasma protein binding ability in AA rats after oral administration within the tested dosage range. It suggested that GE showed slow distribution into the intra- and extracellular space, and the binding rate was not proportionally dependent on plasma concentration of GE when the concentration of GE was

  4. Trace quantification of 1-triacontanol in beagle plasma by GC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Wang, Chunfeng; Fan, Ali; Zhu, Xiaojie; Lu, Yang; Deng, Shuhua; Gao, Wenchao; Zhang, Wei; Liu, Qi; Chen, Xijing

    2015-05-01

    1-Triacontanol (TA), a member of long chain fatty alcohol, has recently been received great attention owing to its antitumor activity. In this study, an accurate, sensitive and selective gas chromatography-tandem mass spectrometry method was developed and validated for the quantification of TA in beagle plasma using 1-octacosanal as the internal standard (IS) for the first time. With temperature programming, chromatographic separation was carried out on an HP-5MS column, using helium as carrier gas and argon as collision gas, both at a flow rate of 1 mL/min. TA was analyzed using positive ion electrospray ionization in multiple-reaction monitoring mode, with the precursor to product ion transitions of m/z 495.6 → 97.0 and m/z 467.5 → 97.0 for TA and the IS, respectively. The lower limit of quantitation, linearity, intra- and interday precision, accuracy, stability, extraction recovery and matrix effect of TA were within the acceptable limits. The validated method was successfully applied to a pharmacokinetic study of TA in beagles.

  5. Weakly Ionized Plasmas in Hypersonics: Fundamental Kinetics and Flight Applications

    SciTech Connect

    Macheret, Sergey

    2005-05-16

    The paper reviews some of the recent studies of applications of weakly ionized plasmas to supersonic/hypersonic flight. Plasmas can be used simply as means of delivering energy (heating) to the flow, and also for electromagnetic flow control and magnetohydrodynamic (MHD) power generation. Plasma and MHD control can be especially effective in transient off-design flight regimes. In cold air flow, nonequilibrium plasmas must be created, and the ionization power budget determines design, performance envelope, and the very practicality of plasma/MHD devices. The minimum power budget is provided by electron beams and repetitive high-voltage nanosecond pulses, and the paper describes theoretical and computational modeling of plasmas created by the beams and repetitive pulses. The models include coupled equations for non-local and unsteady electron energy distribution function (modeled in forward-back approximation), plasma kinetics, and electric field. Recent experimental studies at Princeton University have successfully demonstrated stable diffuse plasmas sustained by repetitive nanosecond pulses in supersonic air flow, and for the first time have demonstrated the existence of MHD effects in such plasmas. Cold-air hypersonic MHD devices are shown to permit optimization of scramjet inlets at Mach numbers higher than the design value, while operating in self-powered regime. Plasma energy addition upstream of the inlet throat can increase the thrust by capturing more air (Virtual Cowl), or it can reduce the flow Mach number and thus eliminate the need for an isolator duct. In the latter two cases, the power that needs to be supplied to the plasma would be generated by an MHD generator downstream of the combustor, thus forming the 'reverse energy bypass' scheme. MHD power generation on board reentry vehicles is also discussed.

  6. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

    Shirazi, Hanieh Safizadeh; Rogers, Nicholas; Michelmore, Andrew; Whittle, Jason D

    2016-01-01

    Furfuryl methacrylate (FMA) is a promising precursor for producing polymers for biomedical and cell therapy applications. Herein, FMA plasma polymer coatings were prepared with different powers, deposition times, and flow rates. The plasma polymer coatings were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results from AFM and SEM show the early growth of the coatings and the existence of particle aggregates on the surfaces. XPS results indicated no measureable chemical differences between the deposited films produced under different power and flow rate conditions. ToF-SIMS analysis demonstrated differing amounts of C5H5O (81 m/z) and C10H9O2 (161 m/z) species in the coatings which are related to the furan ring structure. Through judicious choice of plasma polymerization parameters, the quantity of the particle aggregates was reduced, and the fabricated plasma polymer coatings were chemically uniform and smooth. Primary human fibroblasts were cultured on FMA plasma polymer surfaces to determine the effect of surface chemical composition and the presence of particle aggregates on cell culture. Particle aggregates were shown to inhibit fibroblast attachment and proliferation.

  7. Diagnostics and biomedical applications of radiofrequency plasmas

    NASA Astrophysics Data System (ADS)

    Lazović, Saša

    2012-11-01

    In this paper we present spatial profiles of ion and atomic oxygen concentrations in a large scale cylindrical 13.56 MHz capacitively coupled plasma low pressure reactor suitable for indirect biomedical applications (like treatment of textile to increase antibacterial properties) and direct (treatment of seeds of rare and protected species). Such reactor can easily be used for the sterilization of medical instruments by removing bacteria, spores, prions and fungi as well. We also discuss electrical properties of the system based on the signals obtained by the derivative probes and show the light emission profiles close to the sample platform. In the case of seeds treatment, the desired effect is to plasma etch the outer shell of the seed which will lead to the easier nutrition and therefore increase of the germination. In the case of textile treatment the functionalization is done by bounding atomic oxygen to the surface. It appears that antibacterial properties of the textile are increased by incorporating nanoparticles to the fibres which can successfully be done after the plasma treatment. From these two examples it is obvious that the balance of ion and atomic oxygen concentrations as well as proper choice of ion energy and power delivered to the plasma direct the nature of the plasma treatment.

  8. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

    Shirazi, Hanieh Safizadeh; Rogers, Nicholas; Michelmore, Andrew; Whittle, Jason D

    2016-01-01

    Furfuryl methacrylate (FMA) is a promising precursor for producing polymers for biomedical and cell therapy applications. Herein, FMA plasma polymer coatings were prepared with different powers, deposition times, and flow rates. The plasma polymer coatings were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results from AFM and SEM show the early growth of the coatings and the existence of particle aggregates on the surfaces. XPS results indicated no measureable chemical differences between the deposited films produced under different power and flow rate conditions. ToF-SIMS analysis demonstrated differing amounts of C5H5O (81 m/z) and C10H9O2 (161 m/z) species in the coatings which are related to the furan ring structure. Through judicious choice of plasma polymerization parameters, the quantity of the particle aggregates was reduced, and the fabricated plasma polymer coatings were chemically uniform and smooth. Primary human fibroblasts were cultured on FMA plasma polymer surfaces to determine the effect of surface chemical composition and the presence of particle aggregates on cell culture. Particle aggregates were shown to inhibit fibroblast attachment and proliferation. PMID:27609095

  9. Formation and emission characteristics of CN molecules in laser induced low pressure He plasma and its applications to N analysis in coal and fossilization study.

    PubMed

    Lahna, Kurnia; Idroes, Rinaldi; Idris, Nasrullah; Abdulmadjid, Syahrun Nur; Kurniawan, Koo Hendrik; Tjia, May On; Pardede, Marincan; Kagawa, Kiichiro

    2016-03-01

    Presented in this paper are the results of an experimental study on the laser induced plasma emission of a number of CN free samples (urea, sucrose) with 40 mJ pulse energy using He and N₂ ambient gases. It is shown that the CN emission has its exclusive sources in the molecules produced as the result of chemical bonding either between the ablated C and N ions in the He plasma or between the ablated C and dissociated N from the N₂ ambient gas. The emission intensities in both cases are found to have the highest values at the low gas pressure of 2 kPa. The emission in He gas is shown to exhibit the typical characteristics related to a shockwave generated excitation mechanism. The experiments using He ambient gas further demonstrate the feasible laser-induced breakdown spectroscopy application to quantitative and sensitive N analysis of coal and promising application for practical in situ carbon dating of fossils. PMID:26974637

  10. Laser-Induced Underwater Plasma And Its Spectroscopic Applications

    SciTech Connect

    Lazic, Violeta

    2008-09-23

    Applications of Laser Induced Breakdown Spectroscopy (LIBS) for analysis of immersed solid and soft materials, and for liquid impurities are described. A method for improving the LIBS signal underwater and for obtaining quantitative analyses in presence of strong shot-to-shot variations of the plasma properties is proposed. Dynamic of the gas bubble formed by the laser pulse is also discussed, together with its importance in Double-Pulse (DP) laser excitation. Results of the studies relative to an application of multi-pulse sequence and its effects on the plasma and gas bubble formation are also presented.

  11. Artificial vesicles as an animal cell model for the study of biological application of non-thermal plasma

    NASA Astrophysics Data System (ADS)

    Ki, S. H.; Park, J. K.; Sung, C.; Lee, C. B.; Uhm, H.; Choi, E. H.; Baik, K. Y.

    2016-03-01

    Artificial cell-like model systems can provide information which is hard to obtain with real biological cells. Giant unilamellar vesicles (GUV) containing intra-membrane DNA or OH radical-binding molecules are used to visualize the cytolytic activity of OH radicals. Changes in the GUV membrane are observed by microscopy or flow cytometry as performed for animal cells after non-thermal plasma treatment. The experimental data shows that OH radicals can be detected inside the membrane, although the biological effects are not as significant as for H2O2. This artificial model system can provide a systemic means to elucidate the complex interactions between biological materials and non-thermal plasma.

  12. Determination of underivatized glucosamine in human plasma by high-performance liquid chromatography with electrochemical detection: application to pharmacokinetic study.

    PubMed

    Pashkova, E; Pirogov, A; Bendryshev, A; Ivanaynen, E; Shpigun, O

    2009-11-01

    A simple, rapid and sensitive high-performance liquid chromatography method with electrochemical detection was developed for the determination of glucosamine in human plasma. Plasma samples were analyzed after a simple two-step procedure of protein precipitation with subsequent dilution. The chromatographic separation was performed on a Carbopack column (3 mm x 150 mm) with a mobile phase consisting of water and 200 mM sodium hydroxide. Detection was performed electrochemically in a pulsed voltammetry mode. The limit of detection was 2.0 ng/ml, inter- and intra-day precision were less than 10%. The method was successfully applied to the investigation of the pharmacokinetics of glucosamine in healthy man volunteers.

  13. A high performance liquid chromatography-tandem mass spectrometric method for the determination of mefenamic acid in human plasma: application to pharmacokinetic study.

    PubMed

    Mahadik, Mahadeo; Dhaneshwar, Sunil; Bhavsar, Ravindra

    2012-10-01

    In the present study, the development and validation of an LC-MS/MS method for quantifying mefenamic acid in human plasma is described. The method involves liquid-liquid extraction using diclofenac as an internal standard (IS). Chromatographic separation was achieved on a Thermo Hypurity C(18) , 50 × 4.6 mm, 5 µm column with a mobile phase consisting of 2 m m ammonium acetate buffer and methanol (pH 4.5 adjusted with glacial acetic acid; 15:85, v/v) at a flow-rate of 0.75 mL/min and the total run time was 1.75 min. Analyte was introduced to the LC-MS/MS using an atmospheric pressure ionization source. Both the drug and IS were detected in negative-ion mode using multiple reaction monitoring m/z 240.0 → 196.3 and m/z 294.0 → 250.2, respectively, with a dwell time of 200 ms for each of the transitions. The standard curve was linear from 20 to 6000 ng/mL. This assay allows quantification of mefenamic acid at a concentration as low as 20 ng/mL in human plasma. The observed mean recovery was 73% for the drug. The applicability of this method for pharmacokinetic studies has been established after successful application during a 12-subject bioavailabity study. PMID:22275128

  14. Development and validation of sensitive and rapid UPLC-MS/MS method for quantitative determination of daclatasvir in human plasma: Application to a bioequivalence study.

    PubMed

    Rezk, Mamdouh R; Bendas, Ehab R; Basalious, Emad B; Karim, Iman A

    2016-09-01

    A rapid and sensitive UPLC-MS/MS method was developed and validated for determination of daclatasvir (DAC) in human plasma using sofosbuvir (SOF) as an internal standard (IS). The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Precipitation with acetonitrile was used in sample preparation. The prepared samples were chromatographed on Acquity UPLC HSS C18 (50×2.1mm, 1.8μm) column by pumping 10mM ammonium formate (pH 3.5) and acetonitrile in an isocratic mode at a flow rate of 0.30ml/min. Method validation was performed as per the FDA guidelines and the standard curves were found to be linear in the range of 5-4000ng/ml for DAC. The intra-day and inter-day precision and accuracy results were within the acceptable limits. A very short run time of 1.2min made it possible to analyze more than 500 human plasma samples per day. The wider range of quantification of DAC allowed the applicability of the developed method for its determination in a bioequivalence study in human volunteers. PMID:27232152

  15. Development and validation of a gas chromatography-mass spectrometry method for the determination of phenazopyridine in rat plasma: application to the pharmacokinetic study.

    PubMed

    Chen, Qinhua; Li, Kaijun; Zhang, Zhuo; Li, Peng; Liu, Jia; Li, Qiang

    2007-11-01

    Phenazopyridine hydrochloride is a strong analgesic used in the treatment of urinary tract infections. The aim of the present study was to develop a procedure based on gas chromatography-mass spectrometry (GC-MS) for the analysis of phenazopyridine in rat plasma. The method was set up and adapted for the analysis of small biological samples taken from rats. Biological samples were extracted by liquid-liquid extraction. The extraction agent was ethyl acetate. The samples were separated by GC on a DB-5MS analytical column and determined by a quadrupole mass spectrometer detector operated under selected ion monitoring mode. Excellent linearity was found between 0.01 and 1.00 microg/ml (r = 0.9991, n = 9) for plasma samples. The limit of detection (LOD) was 0.3 ng/ml. Within-day and between-day precisions expressed as the relative standard deviation (RSD) for the method were 1.83-4.91% and 2.12-4.76%, respectively. The recoveries for all samples were >90%. The main pharmacokinetic parameters obtained were T(max) = (0.35+/-0.01) h, C(max) = (0.396+/-0.079) microg/ml, AUC = (0.373+/-0.065) h microg/ml and CL = (94.2+/-5.9) ml/g/h. The results presented here clearly indicate that this proposed method could be applicable to investigate the pharmacokinetic of phenazopyridine in rats after administration. (c)

  16. Determination of rizatriptan in human plasma by liquid chromatographic-eletrospray tandem mass spectrometry: application to a pharmacokinetic study.

    PubMed

    Guo, Ji-fen; Zhang, Ai-jun; Zhao, Ling; Sun, Xiao-hong; Zhao, Yi-min; Gao, Hong-zhi; Liu, Ze-yuan; Qiao, Shan-yi

    2006-01-01

    A sensitive liquid chromatographic-tandem mass spectrometry(LC-MS/MS) method was developed for the determination of rizatriptan in human plasma. The analytes were extracted from plasma samples by liquid-liquid extraction, separated on a Zorbax XDB C8 column (150 x 4.6 mm i.d.) and detected by tandem mass spectrometry with an electrospray ionization interface. Zomitriptan was used as the internal standard. The method had a lower limit of quantitation of 50 pg/mL for rizatriptan, which showed more sensitivity and speed of analysis compared with reported methods. The within- and between-day precision was measured to be below 11.71% and accuracy between -5.87 and 0.86% for all quality control samples. This quantitation method was successfully applied to the evaluation of the pharmacokinetic profiles of rizatriptan after single oral administration of 5, 10 and 15 mg rizatriptan tablets to 10 healthy volunteers (five males and five females). PMID:15954161

  17. Inverse mirror plasma experimental device (IMPED) - a magnetized linear plasma device for wave studies

    NASA Astrophysics Data System (ADS)

    Bose, Sayak; Chattopadhyay, P. K.; Ghosh, J.; Sengupta, S.; Saxena, Y. C.; Pal, R.

    2015-04-01

    In a quasineutral plasma, electrons undergo collective oscillations, known as plasma oscillations, when perturbed locally. The oscillations propagate due to finite temperature effects. However, the wave can lose the phase coherence between constituting oscillators in an inhomogeneous plasma (phase mixing) because of the dependence of plasma oscillation frequency on plasma density. The longitudinal electric field associated with the wave may be used to accelerate electrons to high energies by exciting large amplitude wave. However when the maximum amplitude of the wave is reached that plasma can sustain, the wave breaks. The phenomena of wave breaking and phase mixing have applications in plasma heating and particle acceleration. For detailed experimental investigation of these phenomena a new device, inverse mirror plasma experimental device (IMPED), has been designed and fabricated. The detailed considerations taken before designing the device, so that different aspects of these phenomena can be studied in a controlled manner, are described. Specifications of different components of the IMPED machine and their flexibility aspects in upgrading, if necessary, are discussed. Initial results meeting the prerequisite condition of the plasma for such study, such as a quiescent, collisionless and uniform plasma, are presented. The machine produces δnnoise/n <= 1%, Luniform ~ 120 cm at argon filling pressure of ~10-4 mbar and axial magnetic field of B = 1090 G.

  18. Validation of a simple HPLC-UV method for rifampicin determination in plasma: Application to the study of rifampicin arteriovenous concentration gradient.

    PubMed

    Goutal, Sébastien; Auvity, Sylvain; Legrand, Tiphaine; Hauquier, Fanny; Cisternino, Salvatore; Chapy, Hélène; Saba, Wadad; Tournier, Nicolas

    2016-05-10

    In clinical practice, rifampicin exposure is estimated from its concentration in venous blood samples. In this study, we hypothesized that differences in rifampicin concentration may exist between arterial and venous plasma. An HPLC-UV method for determining rifampicin concentration in plasma using rifapentine as an internal standard was validated. The method, which requires a simple protein precipitation procedure as sample preparation, was performed to compare venous and arterial plasma kinetics after a single therapeutic dose of rifampicin (8.6 mg/kg i.v, infused over 30 min) in baboons (n=3). The method was linear from 0.1 to 40 μg mL(-1) and all validation parameters fulfilled the international requirements. In baboons, rifampicin concentration in arterial plasma was higher than in venous plasma. Arterial Cmax was 2.1±0.2 fold higher than venous Cmax. The area under the curve (AUC) from 0 to 120 min was ∼80% higher in arterial plasma, indicating a significant arteriovenous concentration gradient in early rifampicin pharmacokinetics. Arterial and venous plasma concentrations obtained 6h after rifampicin injection were not different. An important arteriovenous equilibration delay for rifampicin pharmacokinetics is reported. Determination in venous plasma concentrations may considerably underestimate rifampicin exposure to organs during the distribution phase. PMID:26907700

  19. Determination of amine and aldehyde surface densities: application to the study of aged plasma treated polyethylene films.

    PubMed

    Ghasemi, Mahsa; Minier, Michel; Tatoulian, Michaël; Arefi-Khonsari, Farzaneh

    2007-11-01

    The aim of this work was to test and to compare different methods reported in the literature to quantify amine and aldehyde functions on the surface of polyethylene (PE) films treated by ammonia plasma and to specify their stability against time. A low pressure ammonia plasma reactor was used to functionalize PE films with amine groups, which could be subsequently used for further immobilization of biomolecules. In order to determine the density of amine groups on the surface of treated films, various molecule probes and spectrophotometric analytical methods have been investigated. Two methods using (i) sulfosuccinimidyl 6-[3'-(2-pyridyldithio)-propionamido] hexanoate (sulfo-LC-SPDP) and (ii) 2-iminothiolane (ITL) associated with bicinchoninic acid (BCA) have been proved to be reliable and sensitive enough to estimate the surface concentration of primary amine functions. The amount of primary amino groups on the functionalized polyethylene films was found to be between 1.2 and 1.4 molecules/nm2. In a second step, the surface concentration of glutaraldehyde (GA), which is currently used as a spacer arm before immobilization of biomolecules, has been assessed: two methods were used to determine the surface density of available aldehyde functions, after the reaction of GA with the aminated polyethylene film. The concentration of GA was found to be in the same range as primary amine concentration. The influence of aging time on the density of available amino and aldehyde groups on the surfaces were evaluated under different storage conditions. The results showed that 50% of the initial density of primary amine functions remained available after storage during 6 days of the PE samples in PBS (pH 7.6) at 4 degrees C. In the case of aldehyde groups, the same percentage of the initial density (50%) remained active after storage in air at RT over a longer period, i.e., 15 days.

  20. Rapid and sensitive ultra-high-pressure liquid chromatography method for quantification of antichagasic benznidazole in plasma: application in a preclinical pharmacokinetic study.

    PubMed

    Davanço, Marcelo Gomes; de Campos, Michel Leandro; Peccinini, Rosângela Gonçalves

    2015-07-01

    Benznidazole (BNZ) and nifurtimox are the only drugs available for treating Chagas disease. In this work, we validated a bioanalytical method for the quantification of BNZ in plasma aimed at improving sensitivity and time of analysis compared with the assays already published. Furthermore, we demonstrated the application of the method in a preclinical pharmacokinetic study after administration of a single oral dose of BNZ in Wistar rats. A Waters® Acquity UHPLC system equipped with a UV-vis detector was employed. The method was established using an Acquity® UHPLC HSS SB C18 protected by an Acquity® UHPLC HSS SB C18 VanGuard guard column and detection at 324 nm. The mobile phase consisted of ultrapure water-acetonitrile (65:35), and elution was isocratic. The mobile phase flow rate was 0.55 mL/min, the volume of injection was 1 μL, and the run time was just 2 min. The samples were kept at 25°C until injection and the column at 45°C for the chromatographic separation. The sample preparation was performed by a rapid protein precipitation with acetonitrile. The linear concentration range was 0.15-20 µg/mL. The pharmacokinetic parameters of BNZ in rats were determined and the method was considered sensitive, fast and suitable for application in pharmacokinetic studies.

  1. Microstructure studies of air-plasma-spray-deposited CoNiCrAlY coatings before and after thermal cyclic loading for high-temperature application

    NASA Astrophysics Data System (ADS)

    Kumar, Dipak; Pandey, K. N.; Das, Dipak Kumar

    2016-08-01

    In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying (APS) techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and atomic force microscopy (AFM) were used to investigate the phases and microstructure of the as-sprayed, APS-deposited CoNiCrAlY bond-coatings. The aim of this work was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of the γ/γ'-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in CoNiCrAlY bond-coatings with excellent thermal cyclic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.

  2. Method development and validation of liquid chromatography-tandem/mass spectrometry for aldosterone in human plasma: Application to drug interaction study of atorvastatin and olmesartan combination.

    PubMed

    Das, Rakesh; Dan, Subhasis; Pal, Tapan Kumar

    2014-07-01

    In the present investigation, a simple and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) method was developed for the quantification of aldosterone (ALD) a hormone responsible for blood pressure in human plasma. The developed method was validated and extended for application on human subjects to study drug interaction of atorvastatin (ATSV) and olmesartan (OLM) on levels of ALD. The ALD in plasma was extracted by liquid-liquid extraction with 5 mL dichloromethane/ethyl ether (60/40% v/v). The chromatographic separation of ALD was carried on Xterra, RP-Column C18 (150 mm× 4.6 mm × 3.5 μm) at 30°C followed by four-step gradient program composed of methanol and water. Step 1 started with 35% methanol for first 1 min and changed linearly to 90% in next 1.5 min in Step 2. Step 3 lasted for next 2 min with 90% methanol. The method finally concluded with Step 4 to achieve initial concentration of methanol that is, 35% thus contributing the total method run time of 17.5 min. The flow rate was 0.25 mL/min throughout the process. The developed method was validated for specificity, accuracy, precision, stability, linearity, sensitivity, and recovery. The method was linear and found to be acceptable over the range of 50-800 ng/mL. The method was successfully applied for the drug interaction study of ATSV + OLM in combination against OLM treatment on blood pressure by quantifying changes in levels of ALD in hypertensive patients. The study revealed levels of ALD were significantly higher in ATSV + OLM treatment condition when compared to OLM as single treated condition. This reflects the reason of low effectiveness of ATSV + OLM in combination instead of synergistic activity.

  3. Method development and validation of liquid chromatography-tandem/mass spectrometry for aldosterone in human plasma: Application to drug interaction study of atorvastatin and olmesartan combination

    PubMed Central

    Das, Rakesh; Dan, Subhasis; Pal, Tapan Kumar

    2014-01-01

    In the present investigation, a simple and sensitive liquid chromatography-tandem mass spectrometry (LC/MS/MS) method was developed for the quantification of aldosterone (ALD) a hormone responsible for blood pressure in human plasma. The developed method was validated and extended for application on human subjects to study drug interaction of atorvastatin (ATSV) and olmesartan (OLM) on levels of ALD. The ALD in plasma was extracted by liquid-liquid extraction with 5 mL dichloromethane/ethyl ether (60/40% v/v). The chromatographic separation of ALD was carried on Xterra, RP-Column C18 (150 mm× 4.6 mm × 3.5 μm) at 30°C followed by four-step gradient program composed of methanol and water. Step 1 started with 35% methanol for first 1 min and changed linearly to 90% in next 1.5 min in Step 2. Step 3 lasted for next 2 min with 90% methanol. The method finally concluded with Step 4 to achieve initial concentration of methanol that is, 35% thus contributing the total method run time of 17.5 min. The flow rate was 0.25 mL/min throughout the process. The developed method was validated for specificity, accuracy, precision, stability, linearity, sensitivity, and recovery. The method was linear and found to be acceptable over the range of 50-800 ng/mL. The method was successfully applied for the drug interaction study of ATSV + OLM in combination against OLM treatment on blood pressure by quantifying changes in levels of ALD in hypertensive patients. The study revealed levels of ALD were significantly higher in ATSV + OLM treatment condition when compared to OLM as single treated condition. This reflects the reason of low effectiveness of ATSV + OLM in combination instead of synergistic activity. PMID:25126531

  4. Quantification of busulfan in plasma by liquid chromatography-ion spray mass spectrometry. Application to pharmacokinetic studies in children.

    PubMed

    Quernin, M H; Duval, M; Litalien, C; Vilmer, E; Aigrain, E J

    2001-11-01

    Optimisation of busulfan dosage in patients undergoing bone marrow transplantation is recommended in order to reduce toxic effects associated with high drug exposure. A new method was developed coupling liquid chromatography with mass spectrometry (LC-MS) and was validated for the determination of busulfan concentrations in plasma. Recovery was 86.7%, the limit of detection was 2.5 ng/ml and linearity ranged from 5 to 2500 ng/ml. The correlation between the busulfan concentrations measured by our previously published HPLC-UV method and the new HPLC-MS method was highly significant (P<0.0001). Sample volume was reduced and the method was rapid, sensitive and less expensive than the methods previously used in our laboratory. This method was used to determine the pharmacokinetic parameters of busulfan after the first administration of 1 mg/kg orally, in 13 children receiving the drug as part of the preparative regimen for bone marrow transplantation. Our results were similar to previously reported data. They showed that the apparent oral clearance of busulfan was 0.299+/-0.08 l/h/kg, and that it was significantly higher (P=0.02) in patients below the age of 5 years than in older children.

  5. Determination of swertianolin in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    He, Jun; Tian, Chengwang; Ouyang, Huizi; Adelakun, Tiwalade A; Yu, Bin; Chang, Yanxu; Pan, Guixiang; Jiang, Linghuo; Gao, Xiumei

    2014-10-01

    A sensitive and rapid LC-MS/MS method has been developed and validated for quantifying swertianolin in rat plasma using rutin as an internal standard (IS). Following liquid-liquid extraction with ethyl acetate, chromatographic separation for swertianolin was achieved on a C18 column with a gradient elution using 0.1% formic acid as mobile phase A and acetonitrile as mobile phase B at a flow rate of 0.3 mL/min. The detection was performed on a tandem mass spectrometer using multiple reaction monitoring via an electrospray ionization source and operating in the negative ionization mode. The optimized mass transition ion pairs (m/z) for quantitation were 435.1/272.0 for swertianolin and 609.2/300.1 for IS. The lower limit of quantitation was 0.5 ng/mL within a linear range of 0.5-500 ng/mL. Intra-day and inter-day precision was less than 6.8%. The accuracy was in the range of -13.9 to 12.0%. The mean recovery of swertianolin was >66.7%. The proposed method was successfully applied in evaluating the pharmacokinetics of swertianolin after an oral dose of 50 mg/kg Swertia mussotii extract in rats.

  6. Developments and Plasma Studies at the ATOMKI-ECRIS

    SciTech Connect

    Biri, S.; Valek, A.; Takacs, E.; Radics, B.; Palinkas, J.; Karacsony, J.; Kenez, L.; Kitagawa, A.; Muramatsu, M.

    2005-03-15

    The 14.5 GHz ECR ion source of the ATOMKI is a stand-alone device producing highly charged ion beams for ion-surface experiments and a variety of low charged plasmas and beams for plasma physics studies and for practical applications. In the past two years we performed plasma diagnostics measurements using Langmuir-probes and X-ray camera. Langmuir-probe results allowed estimating the plasma potential close to the resonance zone. The studying of X-ray pictures of Xe-Ar plasmas helps understanding the gas-mixing phenomena. A mixture plasma of fullerene and ferrocene was generated and FeC60 hybrid molecules were detected in the extracted beam.

  7. Cold plasma: overview of plasma technologies and applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cold plasma is a novel nonthermal food processing technology. It is based on energetic, reactive gases which inactivate contaminating microbes on meats, poultry and fruits and vegetables. The primary modes of action are due to UV light and reactive chemical products of the cold plasma ionization pro...

  8. An Experimental Study of a Pulsed Electromagnetic Plasma Accelerator

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Eskridge, Richard; Lee, Mike; Smith, James; Martin, Adam; Markusic, Tom E.; Cassibry, Jason T.; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    Experiments are being performed on the NASA Marshall Space Flight Center (MSFC) pulsed electromagnetic plasma accelerator (PEPA-0). Data produced from the experiments provide an opportunity to further understand the plasma dynamics in these thrusters via detailed computational modeling. The detailed and accurate understanding of the plasma dynamics in these devices holds the key towards extending their capabilities in a number of applications, including their applications as high power (greater than 1 MW) thrusters, and their use for producing high-velocity, uniform plasma jets for experimental purposes. For this study, the 2-D MHD modeling code, MACH2, is used to provide detailed interpretation of the experimental data. At the same time, a 0-D physics model of the plasma initial phase is developed to guide our 2-D modeling studies.

  9. Analysis on electromagnetic characteristics and military application of non-magnetized discharge plasma

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Wang, Jiachun; Miao, Lei; Li, Zhigang

    2015-11-01

    Firstly, the dispersion equation of a plane electromagnetic wave in homogeneous and non-magnetized discharge plasma was established. According to the different frequency of electromagnetic wave and plasma parameters, the characteristics were discussed when the plasma interacted with electromagnetic waves. Then the gas discharge approach was put forward according to characteristics of plasma generated by different methods and their advantages and disadvantages. The possibility of using non-magnetized discharge plasma for the military purpose was analyzed. In the end, the principle and characteristics of the application of the non-magnetized discharge plasma were studied in the fields of stealth and protection against strong electromagnetic pulse.

  10. Biological and Agricultural Studies on Application of Discharge Plasma and Electromagnetic Fields 4. Destruction of Weeds by High Voltage Discharge

    NASA Astrophysics Data System (ADS)

    Mizuno, Akira

    In an attempt to replace chemicals for weed control, high voltage spark discharge has been applied. With the application of high voltage, discharge takes place, and current flows through the stem and root. Microscopic observation indicates that cells are damaged. The electrical resistance of the damage plant’s stems and roots decreased significantly. Several different types of apparatus were constructed, and field test results show the effectiveness of electrical discharge for weed control.

  11. Spectroscopy Study of Ar + CO2 Plasmas in ASTRAL.

    NASA Astrophysics Data System (ADS)

    Munoz, Jorge; Boivin, Robert; Kamar, Ola; Loch, Stuart; Ballance, Connor

    2006-10-01

    A spectroscopy study of the ASTRAL (Auburn Steady sTate Research fAciLity) helicon plasma source running Ar + CO2 gas mix is presented. ASTRAL produces Ar plasmas: ne = 10^10 to 10^13 cm-3, Te = 2 to 10 eV and Ti = 0.03 to 0.5 eV. A series of 7 large coils produce an axial magnetic field up to 1.3 kGauss. A fractional helix antenna is used to introduce rf power up to 2 kWatt. A spectrometer which features a 0.33 m Criss-Cross monochromator and a CCD camera is used for this study. Very different plasmas are produced following the relative importance of CO2 in the gas mixture. At low CO2 concentration, the plasmas are similar to those obtained with pure Ar with weak CO2, CO2^+, CO and CO^+ bands. The usual blue plasma core associated with intense Ar II transitions is observed with however a significant white glow coming from the outer plasma regions. At higher CO2 concentration, the plasma becomes essentially molecular and can be described as an intense white plasma column. Molecular dissociative processes associated with the production of strong C and O atomic lines are observed under specific plasma conditions. The atomic spectral lines are compared with ADAS modeling results. This study indicates the possible advantages of using a helicon source to control the CO2 plasma chemistry for industrial applications.

  12. The study of helicon plasma source

    SciTech Connect

    Miao Tingting; Shang Yong; Zhao Hongwei; Liu Zhanwen; Sun Liangting; Zhang Xuezhen; Zhao Huanyu

    2010-02-15

    Helicon plasma source is known as efficient generator of uniform and high density plasma. A helicon plasma source was developed for investigation of plasma neutralization and plasma lens in the Institute of Modern Physics in China. In this paper, the characteristics of helicon plasma have been studied by using Langmuir four-probe and a high argon plasma density up to 3.9x10{sup 13} cm{sup -3} have been achieved with the Nagoya type III antenna at the conditions of the magnetic intensity of 200 G, working gas pressure of 2.8x10{sup -3} Pa, and rf power of 1200 W with a frequency of 27.12 MHz. In the experiment, the important phenomena have been found: for a given magnetic induction intensity, the plasma density became greater with the increase in rf power and tended to saturation, and the helicon mode appeared at the rf power between 200 and 400 W.

  13. Quantitative determination of microbicidal spermicide 'nonoxynol-9' in rabbit plasma and vaginal fluid using LC-ESI-MS/MS: application to pharmacokinetic study.

    PubMed

    Chhonker, Yashpal S; Chandasana, Hardik; Bala, Veenu; Kumar, Lokesh; Sharma, Vishnu Lal; Gupta, Gopal; Bhatta, Rabi S

    2014-08-15

    Nonoxynol-9 (N-9), a microbicidal spermicide, has been in use as an over-the-counter contraceptive since the 1960s. A detailed account of its pharmacokinetic profile using highly sensitive detection method has not been reported yet. We developed and validated a rapid, selective and sensitive high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for N-9 detection in plasma and simulated vaginal fluid. The analytes were quantified using reverse phase Thermo Accucore C18 (150 mm × 4.6mm, 5 μm) column with isocratic elution using acetonitrile: 0.1% formic acid in triple distilled water (90:10, v/v) as mobile phase. The ionization was optimized using ESI (+) and selectivity was achieved by tandem mass spectrometric analysis using MRM transition, m/z 617.4→133.2 for N-9 and m/z 180.1→138.1 for phenacetin. The method was linear over the range 0.195-100 ng/mL. The method was accurate and precise with intra-batch and inter-batch accuracy (% bias) of less than ± 15% and precision (% CV) of <15% for N-9. The mean peak plasma concentration (Cmax) 4.87 ± 0.37 ng/mL was achieved 1.0h after vaginal application with terminal half-life 1.45 ± 0.07 h in rabbits. The validated method was successfully applied for pharmacokinetic study of N-9 in rabbits after vaginal administration. PMID:25016165

  14. Application of Plasma Waveguides to High Energy Accelerators

    SciTech Connect

    Milchberg, Howard M

    2013-03-30

    The eventual success of laser-plasma based acceleration schemes for high-energy particle physics will require the focusing and stable guiding of short intense laser pulses in reproducible plasma channels. For this goal to be realized, many scientific issues need to be addressed. These issues include an understanding of the basic physics of, and an exploration of various schemes for, plasma channel formation. In addition, the coupling of intense laser pulses to these channels and the stable propagation of pulses in the channels require study. Finally, new theoretical and computational tools need to be developed to aid in the design and analysis of experiments and future accelerators. Here we propose a 3-year renewal of our combined theoretical and experimental program on the applications of plasma waveguides to high-energy accelerators. During the past grant period we have made a number of significant advances in the science of laser-plasma based acceleration. We pioneered the development of clustered gases as a new highly efficient medium for plasma channel formation. Our contributions here include theoretical and experimental studies of the physics of cluster ionization, heating, explosion, and channel formation. We have demonstrated for the first time the generation of and guiding in a corrugated plasma waveguide. The fine structure demonstrated in these guides is only possible with cluster jet heating by lasers. The corrugated guide is a slow wave structure operable at arbitrarily high laser intensities, allowing direct laser acceleration, a process we have explored in detail with simulations. The development of these guides opens the possibility of direct laser acceleration, a true miniature analogue of the SLAC RF-based accelerator. Our theoretical studies during this period have also contributed to the further development of the simulation codes, Wake and QuickPIC, which can be used for both laser driven and beam driven plasma based acceleration schemes. We

  15. Determination of manassantin B in rat plasma using a high performance liquid chromatography with fluorescence detection and its quantitative application to pharmacokinetic study.

    PubMed

    Lee, Jae-Young; Song, Jae-Hyoung; Yoon, In-Soo; Ko, Hyun-Jeong; Kim, Dae-Duk; Cho, Hyun-Jong

    2016-02-01

    A simple, sensitive, rapid, and reproducible analytical method of manassantin B in rat plasma by high performance liquid chromatography with fluorescence detection (HPLC-FL) was developed for its application to pharmacokinetic study in rats. Valsartan (VST) was used as an internal standard (IS) in this quantitative analytical method. Manassantin B and VST were extracted by simple and efficient protein precipitation method. Manassantin B was detected at 282/322nm (excitation/emission) wavelengths using FL detector. The chromatographic separation was obtained with reverse phase C18 column and the mobile phase composed of potassium phosphate buffer containing 0.025% trifluoroacetic acid (pH 2.5; 5mM) and acetonitrile including 0.025% trifluoroacetic acid (20:80, v/v) at 1.0mL/min flow rate. The linearity was established at 25.0-10000ng/mL and the lower limit of detection (LLOD) was 7ng/mL. The intra- and inter-day accuracy and precision values of manassantin B were within±15% of the theroretical values and <9% from the nominal concentrations, respectively. Accuracy and precision values of manassantin B after stability tests were also within the acceptable ranges. Developed assay was also successfully applied to pharmacokinetic study after intravenous administration of manassantin B in rats.

  16. Pulse-discharge plasmas for plasma-accelerator applications

    SciTech Connect

    Clayton, C. E.; Joshi, C.; Lopes, N. C.

    2012-12-21

    For particle-beam-driven plasma wakefield accelerators, a long and fully-ionized plasma is desirable. We describe an experiment at UCLA to develop a prototype of such plasma using a pulsed-current discharge. Scaling of the plasma density with glass-tube diameter and with discharge-circuit parameters is currently underway. We have found that 4 Torr of Argon can be fully ionized to a density of about 1.3 Multiplication-Sign 10{sup 17} cm{sup -3} when the current density in the 1 inch diameter, 1.2 meter-long tube is around 2 kA/cm{sup 2}, at least at one point along the discharge. The homogeneity of the plasma density in the longitudinal direction is crucial to prevent slippage of the driven plasma structures with the particles. Equally important are the transverse gradients since any dipole asymmetry in the transverse direction can lead to 'steering' of the particle beam. The longitudinal and transverse gradients may be a function of time into the discharge, the shape of the electrodes, the tube size, and the fractional ionization for a given fill pressure. These issues are currently under investigation.

  17. Low Temperature Plasma Physics: Fundamental Aspects and Applications

    NASA Astrophysics Data System (ADS)

    Hippler, Rainer; Pfau, Sigismund; Schmidt, Martin; Schoenbach, Karl H.

    2001-06-01

    Low-temperature plasma physics is a very active area of research located on the boundaries between physics, chemistry and materials science. Recent technological developments, e.g. in plasma etching or plasma deposition, have led to a revived interest in plasma physics and technology. This volume describes in detail fundamentals and applications of low-temperature plasma physics including newest achievements. The authors of this volume are top scientists from the USA and Europe who present most recent successes in our understanding of how plasmas behave and put a strong focus on the links between theory and experiment or technological process.

  18. Applications of plasma sources for nitric oxide medicine

    NASA Astrophysics Data System (ADS)

    Vasilets, Victor; Shekhter, Anatoly; Pekshev, Alexander

    2013-09-01

    Nitric oxide (NO) has important roles in the function of many tissues and organs. Wound healing processes are always accompanying by the increase of nitric oxide concentration in wound tissue. These facts suggest a possible therapeutic use of various NO donors for the acceleration of the wound healing and treatment of other diseases. Our previous studies indicated that gaseous NO flow produced by air-plasma generators acts beneficially on the wound healing. This beneficial effect could be caused by the mechanism involving peroxynitrite as an intermediate. As a result of mobilization of various antioxidant reactions more endogenous NO molecules become available as signaling molecules. to regulate the metabolic processes in wound tissue. In this paper different air plasma sources generated therapeutic concentrations of NO are discussed. The concentration of NO and other therapeutically important gas products are estimated by thermodynamic simulation. Synergy effects of NO with other plasma components are discussed as a factor enhancing therapeutic results. Some new medical application of plasma devices are presented. Advanced Plasma Therapies Inc.

  19. A sensitive and specific liquid chromatography/tandem mass spectrometry method for determination of pinaverium bromide in human plasma: application to a pharmacokinetic study in healthy volunteers.

    PubMed

    Ren, Jin-Min; Zhao, Xi; Wang, Chuan-Ping; Sun, Qian; Yin, Li-Xin; Zhang, Zhi-Qing

    2011-12-01

    A sensitive and specific method using liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) for the determination of pinaverium bromide in human plasma was developed and validated. Pinaverium bromide and an internal standard (paclitaxel) were isolated from plasma samples by precipitating plasma, and determined by LC-MS/MS in multiple-reaction monitoring mode. The main metabolite of pinaverium bromide and endogenous substances in plasma did not show any interference. The calibration curve was linear over the plasma concentration range of 10.0-10000.0 pg/mL with a correlation coefficient of 0.9979. The relative standard derivations intra- and inter-day at 30.0, 300.0 and 8000.0 pg/mL in plasma were less than 15%. The absolute recoveries of pinaverium bromide and the internal standard were 99.7-111.7 and 106.2%, respectively. The lower limit of quantitation was 10 pg/mL. The analytical method was successfully applied to study the pharmacokinetics of pinaverium bromide tablets in healthy Chinese volunteers. PMID:21308709

  20. Nonthermal Plasma Synthesis of Nanocrystals: Fundamental Principles, Materials, and Applications.

    PubMed

    Kortshagen, Uwe R; Sankaran, R Mohan; Pereira, Rui N; Girshick, Steven L; Wu, Jeslin J; Aydil, Eray S

    2016-09-28

    Nonthermal plasmas have emerged as a viable synthesis technique for nanocrystal materials. Inherently solvent and ligand-free, nonthermal plasmas offer the ability to synthesize high purity nanocrystals of materials that require high synthesis temperatures. The nonequilibrium environment in nonthermal plasmas has a number of attractive attributes: energetic surface reactions selectively heat the nanoparticles to temperatures that can strongly exceed the gas temperature; charging of nanoparticles through plasma electrons reduces or eliminates nanoparticle agglomeration; and the large difference between the chemical potentials of the gaseous growth species and the species bound to the nanoparticle surfaces facilitates nanocrystal doping. This paper reviews the state of the art in nonthermal plasma synthesis of nanocrystals. It discusses the fundamentals of nanocrystal formation in plasmas, reviews practical implementations of plasma reactors, surveys the materials that have been produced with nonthermal plasmas and surface chemistries that have been developed, and provides an overview of applications of plasma-synthesized nanocrystals.

  1. Nonthermal Plasma Synthesis of Nanocrystals: Fundamental Principles, Materials, and Applications.

    PubMed

    Kortshagen, Uwe R; Sankaran, R Mohan; Pereira, Rui N; Girshick, Steven L; Wu, Jeslin J; Aydil, Eray S

    2016-09-28

    Nonthermal plasmas have emerged as a viable synthesis technique for nanocrystal materials. Inherently solvent and ligand-free, nonthermal plasmas offer the ability to synthesize high purity nanocrystals of materials that require high synthesis temperatures. The nonequilibrium environment in nonthermal plasmas has a number of attractive attributes: energetic surface reactions selectively heat the nanoparticles to temperatures that can strongly exceed the gas temperature; charging of nanoparticles through plasma electrons reduces or eliminates nanoparticle agglomeration; and the large difference between the chemical potentials of the gaseous growth species and the species bound to the nanoparticle surfaces facilitates nanocrystal doping. This paper reviews the state of the art in nonthermal plasma synthesis of nanocrystals. It discusses the fundamentals of nanocrystal formation in plasmas, reviews practical implementations of plasma reactors, surveys the materials that have been produced with nonthermal plasmas and surface chemistries that have been developed, and provides an overview of applications of plasma-synthesized nanocrystals. PMID:27550744

  2. Plasma chemistry study of PLAD processes

    NASA Astrophysics Data System (ADS)

    Qin, Shu; Brumfield, Kyle; Liu, Lequn Jennifer; Hu, Yongjun Jeff; McTeer, Allen; Hsu, Wei Hui; Wang, Maoying

    2012-11-01

    Plasma doping (PLAD) shows very different impurity profiles compared to the conventional beam-line-based ion implantations due to its non-mass separation property and plasma environment. There is no simulation for PLAD process so far due to a lack of a dopant profile model. Several factors determine impurity profiles of PLAD process. The most significant factors are: plasma chemistry and deposition/etching characteristics of multi-ion species plasmas. In this paper, we present plasma chemistry and deposition/etching characteristics of PLAD processes versus co-gas dilutions. Four dopant plasmas including B2H6, BF3, AsH3, and PH3, and two non-dopant plasmas including CH4 and GeH4 are studied and demonstrated.

  3. Biological and Agricultural Studies on Application of Discharge Plasma and Electromagnetic Fields 5. Effects of High Electric Fields on Animals

    NASA Astrophysics Data System (ADS)

    Isaka, Katsuo

    The biological effects of extremely low frequency electric fields on animals are reviewed with emphasis on studies of the nervous system, behavior, endocrinology, and blood chemistry. First, this paper provides a histrical overview of studies on the electric field effects initiated in Russia and the United States mainly regarding electric utility workers in high voltage substations and transmission lines. Then, the possible mechanisms of electric field effects are explained using the functions of surface electric fields and induced currents in biological objects. The real mechanisms have not yet been identified. The thresholds of electric field perception levels for rats, baboons, and humans are introduced and compared. The experimental results concerning the depression of melatonin secretion in rats exposed to electric fields are described.

  4. Atmospheric pressure non-thermal plasma: Sources and applications

    NASA Astrophysics Data System (ADS)

    Napartovich, A. P.

    2008-07-01

    Non-thermal plasma at atmospheric pressure is an inherently unstable object. Nature of discharge plasma instabilities and conditions for observation of uniform non-thermal plasma at atmospheric pressure in different environments will be discussed. Various discharge techniques have been developed, which could support uniform non-thermal plasma with parameters varied in a wide range. Time limitation by plasma instabilities can be overcome by shortening pulse length or by restriction of plasma plug residence time with a fast gas flow. Discharge instabilities leading to formation of filaments or sparks are provoked by a positive feedback between the electric field and plasma density, while the counteracting process is plasma and thermal diffusion. With gas pressure growth the size of plasma fluctuation, which could be stabilized by diffusion, diminishes. As a result, to have long lived uniform plasma one should miniaturize discharge. There exist a number of active methods to organize negative feedback between the electric field and plasma density in order to suppress or, at least, delay the instability. Among them are ballast resistors in combination with electrode sectioning, reactive ballast, electronic feedback, and dielectric barrier across the electric current. The last methods are relevant for ac discharges. In the lecture an overview will be given of different discharge techniques scalable in pressure up to one atmosphere. The interest in this topic is dictated by a potential economic benefit from numerous non-thermal plasma technologies. The spectrum of non-thermal plasma applications is continuously broadening. An incomplete list of known applications includes: plasma-assisted chemical vapor deposition, etching, polymerization, gas-phase synthesis, protective coating deposition, toxic and harmful gas decomposition, destruction of warfare agents, electromagnetic wave shielding, polymer surface modifications, gas laser excitation, odor control, plasma assisted

  5. Theoretical study of nonlinear waves and shock-like phenomena in hot plasmas

    NASA Technical Reports Server (NTRS)

    Fried, B. D.; Banos, A., Jr.; Kennel, C. F.

    1973-01-01

    Summaries are presented of research in basic plasma physics. Nonlinear waves and shock-like phenomena were studied which are pertinent to space physics applications, and include specific problems of magnetospheric and solar wind plasma physics.

  6. A Survey of Plasmas and Their Applications

    NASA Technical Reports Server (NTRS)

    Eastman, Timothy E.; Grabbe, C. (Editor)

    2006-01-01

    Plasmas are everywhere and relevant to everyone. We bath in a sea of photons, quanta of electromagnetic radiation, whose sources (natural and artificial) are dominantly plasma-based (stars, fluorescent lights, arc lamps.. .). Plasma surface modification and materials processing contribute increasingly to a wide array of modern artifacts; e.g., tiny plasma discharge elements constitute the pixel arrays of plasma televisions and plasma processing provides roughly one-third of the steps to produce semiconductors, essential elements of our networking and computing infrastructure. Finally, plasmas are central to many cutting edge technologies with high potential (compact high-energy particle accelerators; plasma-enhanced waste processors; high tolerance surface preparation and multifuel preprocessors for transportation systems; fusion for energy production).

  7. A comparative study of capacitively coupled HBr/He, HBr/Ar plasmas for etching applications: Numerical investigation by fluid model

    SciTech Connect

    Gul, Banat; Aman-ur-Rehman

    2015-10-15

    Fluid model has been applied to perform a comparative study of hydrogen bromide (HBr)/He and HBr/Ar capacitively coupled plasma discharges that are being used for anisotropic etching process. This model has been used to identify the most dominant species in HBr based plasmas. Our simulation results show that the neutral species like H and Br, which are the key player in chemical etching, have bell shape distribution, while ions like HBr{sup +}, Br{sup +}, which play a dominant rule in the physical etching, have double humped distribution and show peaks near electrodes. It was found that the dilution of HBr by Ar and/or He results in an increase in electron density and electron temperature, which results in more ionization and dissociation and hence higher densities of neutral and charged species can be achieved. The ratio of positive ion flux to the neutral flux increases with an increase in additive gas fraction. Compare to HBr/He plasma, the HBr/Ar plasma shows a maximum change in the ion density and flux and hence the etching rate can be considered in the ion-assisted and in the ion-flux etch regime in HBr/Ar discharge. The densities of electron and other dominant species in HBr/Ar plasma are higher than those of HBr/He plasma. The densities and fluxes of the active neutrals and positive ions for etching and subsequently chemical etching versus physical sputtering in HBr/Ar and HBr/He plasmas discharge can be controlled by tuning gas mixture ratio and the desire etching can be achieved.

  8. Study of Photoemissive Dusty Plasma

    SciTech Connect

    Gavrikov, A. V.; Fortov, V. E.; Petrov, O. F.; Babichev, V. N.; Filippov, A. V.; Pal', A. F.; Starostin, A. N.

    2008-09-07

    The present work deals with the experimental and theoretical investigation of photoemissive charging of polydisperse dust particles. The characteristic size of dust particles under consideration was 0.1-25 mkm. The experimental part of this work was devoted to the study of positive charging of macroparticles under UV-radiation that acted on dusty formations. Investigations were carried out in argon at normal pressure with particles of different materials. Dust structure was subjected to radiation. The power and frequency spectrum of this radiation was close to corresponding parameters of sun radiation near the top layers of Earth atmosphere. Owing to electron photoemission the macroparticles became positively charged. On the basis of experimental data the estimation of this charge was performed. It was about 500 elementary charges for micron particles. The theoretical part of present work included the numerical simulation of photoemissive dusty plasma decay in a drift-diffusion approximation. The model included equilibrium equation for positively charged macroparticles (in experiment, the percent of these particles was about 90), negatively charged dust particles (about 10%), positive ions (those were born by electron strike of buffered gas atoms) and electrons. Also the model included the Poisson equation for determination of potential distribution in the discharge region. The results of numerical calculations were in a satisfactory correspondence with experimental data both for time dependences of positively and negatively charged macroparticles concentrations and for their velocities.

  9. [Enantioselective determinination of R-warfarin/S-warfarin in human plasma using liquid chromatography-tandem mass spectrometry and its application in a drug-drug interaction study].

    PubMed

    Jin, Shu; Zhang, Yi-Fan; Chen, Xiao-Yan; Liu, Ke; Zhong, Da-Fang

    2012-01-01

    To study the drug-drug interaction of morinidazole and warfarin and its application, a sensitive and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of R-warfarin/S-warfarin in human plasma. In a random, two-period crossover study, 12 healthy volunteers received a single oral dose of 5 mg racemic warfarin in the absence and presence of morinidazole. Blood samples were collected according to a pre-designed time schedule. R-warfarin, S-warfarin and methyclothiazide were extracted with ethylether : methylenechloride (3 : 2), then separated on a Astec Chirobiotic V (150 mm x 4.6 mm ID, 5 microm) column using 5 mmol x L(-1) ammonium acetate (pH 4.0) - acetonitrile as mobile phase at a flow-rate of 1.5 mL x min(-1). The mobile phase was splitted and 0.5 mL x min(-1) was introduced into MS. A tandem mass spectrometer equipped with electrospray ionization source was used as detector and operated in the negative ion mode. Quantification was performed using multiple reaction monitoring (MRM). The resolution of warfarin enantiomers is 1.56. The linear calibration curves for R-warfarin and S-warfarin both were obtained in the concentration range of 5 - 1 000 ng x mL(-1). Intra- and inter-day relative standard deviation (RSD) for R-warfarin and S-warfarin over the entire concentration range across three validation runs was both less than 10%, and relative error (RE) ranged from -4.9% to 0.7%, separately. The method herein described is effective and convenient, and suitable for the study of metabolic interaction between morinidazole and warfarin. The results showed that coadministration of warfarin with morinidazole did not affect the pharmacokinetics of either R-warfarin or S-warfarin. PMID:22493814

  10. Biomedical Applications of the Cold Atmospheric Plasma: Cell Responses

    NASA Astrophysics Data System (ADS)

    Volotskova, Olga

    Current breakthrough research on cold atmospheric plasma (CAP) demonstrates that CAP has great potential in various areas, including medicine and biology, thus providing a new tool for living tissue treatment. Depending on the configuration the cold plasma sources can be used in the following areas: wound healing, skin diseases, hospital hygiene, sterilization, antifungal treatments, dental care, cosmetics targeted cell/tissue removal, and cancer treatments. This dissertation is focused on the studies of biomedical applications of cold atmospheric plasma jet based on helium flow and resultant cell responses to the cold plasma treatment. The studies were carried out on extra-cellular and intra-cellular levels in vitro. The main practical applications are wound healing and alternative to existing cancer therapy methods, areas of great interest and significant challenges. The CAP jet was built in the Micropropulsion and Nanotechnology Laboratory of Dr. Michael Keidar, as a part of multidisciplinary collaboration with the GW Medical School (Dr. M.A. Stepp) concerned with plasma medicine and bioengineering studies. Normal and cancer cells have two fundamental behavioral properties, proliferation and motility, which can be evaluated through cell migration rates and cell cycle progression. Various microscopic, spectroscopic and flow cytometry techniques were used to characterize cell responses to the cold plasma treatment. It was found that CAP effect on the cells is localized within the area of the treatment (of around ˜ 5mm in diameter). The migration rates of the normal skin cells can be reduced up to ˜ 40%. However, depending on the cell type the required treatment time is different, thus differential treatment of various cells presented in tissue is possible. The CAP effect on the migration was explained through the changes of the cell surface proteins/integrins. It was also found that normal and cancer cells respond differently to the CAP treatment under the same

  11. Platelet-rich plasma: applications in dermatology.

    PubMed

    Conde Montero, E; Fernández Santos, M E; Suárez Fernández, R

    2015-03-01

    In recent years, the use of platelet-rich plasma has increased notably in a range of diseases and settings. Uses of these products now go beyond skin rejuvenation therapy in patients with facial ageing. Good outcomes for other dermatological indications such as skin ulcers and, more recently, alopecia have been reported in case series and controlled studies. However, these indications are not currently included in the labeling given that stronger scientific evidence is required to support their real benefits. With the increased use of these products, dermatologists need to become familiar with the underlying biological principles and able to critically assess the quality and outcomes of the studies of these products in different skin diseases.

  12. Plasma Science and Applications at the Intel

    NASA Astrophysics Data System (ADS)

    Berry, Lee

    2006-10-01

    The Coalition for Plasma Science (CPS) has established a plasma prize at the annual Intel International Science and Engineering Fair (ISEF). The 2006 prize was awarded for a project that investigated the correlation of GPS errors with various measures of near-earth plasma activity. The CPS is a broadly-based group of institutions and individuals whose goal is to increase the understanding of plasmas for non-technical audiences. In addition to the ISEF plasma award, CPS activities include maintaining a website, http://www.plasmacoalition.org; developing educational literature; organizing educational luncheon presentations for Members of Congress and their staffs; and responding to questions about plasmas. In addition, the CPS has begun as effort to examine the plasma content of state education standards with the goal of promoting the adoption of standards with appropriate plasma conten; e.g. are there three or four states of matter. The success of this and other activities depend on the voluntary labor of CPS members and associates. Please send an e-mail to the CPS at CPS@plasmacoalition.org for information if you would like to become involved in spreading the good word about plasmas.

  13. Plasma Tunable LC Resonator for High-Power Electromagnetic Applications

    NASA Astrophysics Data System (ADS)

    Semnani, Abbas; Macheret, Sergey; Peroulis, Dimitrios

    2015-09-01

    High-power tunable filters are in high demand in transmitters found in radars and many communication systems such as satellite and broadcasting stations. Limited power handling renders most semiconductor technologies inherently suboptimal options for these systems. Therefore, mechanically-tunable cavity-based filters are often employed in such cases, resulting in bulky, slow, and heavy systems. In this work, we study the application of plasma as an alternative frequency tuning mechanism for high-power applications even in environmentally and/or mechanically harsh conditions. For a given gas type and pressure, the real and imaginary parts of the dielectric permittivity of a plasma can be varied by changing the electron density, which, depending on the discharge regime, can be implemented by changing the discharge current, voltage, or the magnitude of an auxiliary electric field. In this work, a simple LC resonator tuned to several hundred MHz was fabricated and tested. The tunable capacitor of the resonator was implemented by a commercially available gas discharge tube (GDT), a mm-scale plasma device with gas pressure of 100s of mTorr. Measurement results reveal a continuous tuning range of more than 50% when the applied discharge current is increased from zero to 90 mA.

  14. Development and validation of an RP-HPLC method for the quantitation of odanacatib in rat and human plasma and its application to a pharmacokinetic study.

    PubMed

    Police, Anitha; Gurav, Sandip; Dhiman, Vinay; Zainuddin, Mohd; Bhamidipati, Ravi Kanth; Rajagopal, Sriram; Mullangi, Ramesh

    2015-11-01

    A simple, specific, sensitive and reproducible high-performance liquid chromatography (HPLC) assay method has been developed and validated for the estimation of odanacatib in rat and human plasma. The bioanalytical procedure involves extraction of odanacatib and itraconazole (internal standard, IS) from a 200 μL plasma aliquot with simple liquid-liquid extraction process. Chromatographic separation was achieved on a Symmetry Shield RP18 using an isocratic mobile phase at a flow rate of 0.7 mL/min. The UV detection wave length was 268 nm. Odanacatib and IS eluted at 5.5 and 8.6 min, respectively with a total run time of 10 min. Method validation was performed as per US Food and Drug Administration guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 50.9-2037 ng/mL (r(2) = 0.994). The intra- and inter-day precisions were in the range of 2.06-5.11 and 5.84-13.1%, respectively, in rat plasma and 2.38-7.90 and 6.39-10.2%, respectively, in human plasma. The validated HPLC method was successfully applied to a pharmacokinetic study in rats. PMID:25914381

  15. A sensitive and selective UPLC-MS/MS method for simultaneous determination of 10 alkaloids from Rhizoma Menispermi in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Wei, Jinxia; Fang, Linlin; Liang, Xinlei; Su, Dan; Guo, Xingjie

    2015-11-01

    A sensitive and selective liquid chromatography-tandem mass spectrometry method has been developed and validated for simultaneous quantitation of 10 alkaloids (dauricine, daurisoline, N-desmethyldauricine, dauricicoline, dauriporphinoline, bianfugecine, dauricoside, stepholidine, acutumine and acutumidine) from Rhizoma Menispermi in rat plasma. After addition of internal standard (verapamil), plasma samples were pretreated by a single-step protein precipitation with acetonitrile. Chromatographic separation was performed on a Waters BEH C18 column with gradient elution using a mobile phase composed of acetonitrile and water (containing 0.1% formic acid) at a flow rate of 0.3 mL/min. The analytes were detected without interference in the multiple reaction monitoring (MRM) mode with positive electrospray ionization. The validated method exhibited good linearity over a wide concentration range (r≥0.9914), and the lower limits of quantification were 0.01-5.0 ng/mL for all the analytes. The intra-day and inter-day precisions (RSD) at three different levels were both less than 13.4% and the accuracies (RE) ranged from -12.8% to 13.5%. The mean extraction recoveries of analytes and IS from rat plasma were all more than 77%. The validated method was successfully applied to a comparative pharmacokinetic study of 10 alkaloids in rat plasma after oral administration of Rhizoma Menispermi extract.

  16. Determination of Cefalothin and Cefazolin in Human Plasma, Urine and Peritoneal Dialysate by UHPLC-MS/MS: application to a pilot pharmacokinetic study in humans.

    PubMed

    Parker, Suzanne L; Guerra Valero, Yarmarly C; Roberts, Darren M; Lipman, Jeffrey; Roberts, Jason A; Wallis, Steven C

    2016-06-01

    An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the analysis of cefazolin and cefalothin in human plasma (total and unbound), urine and peritoneal dialysate has been developed and validated. Total plasma concentrations are measured following protein precipitation and are suitable for the concentration range of 1-500 µg/mL. Unbound concentrations are measured from ultra-filtered plasma acquired using Centrifree(®) devices and are suitable for the concentration range of 0.1-500 µg/mL for cefazolin and 1-500 µg/mL for cefalothin. The urine method is suitable for a concentration range of 0.1-20 mg/mL for cefazolin and 0.2-20 mg/mL for cefalothin. Peritoneal dialysate concentrations are measured using direct injection, and are suitable for the concentration range of 0.2-100 µg/mL for both cefazolin and cefalothin. The cefazolin and cefalothin plasma (total and unbound), urine and peritoneal dialysate results are reported for recovery, inter-assay precision and accuracy, and the lower limit of quantification, linearity, stability and matrix effects, with all results meeting acceptance criteria. The method was used successfully in a pilot pharmacokinetic study with patients with peritoneal dialysis-associated peritonitis, receiving either intraperitoneal cefazolin or cefalothin. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Plasma simulation studies using multilevel physics models

    SciTech Connect

    Park, W.; Belova, E.V.; Fu, G.Y.

    2000-01-19

    The question of how to proceed toward ever more realistic plasma simulation studies using ever increasing computing power is addressed. The answer presented here is the M3D (Multilevel 3D) project, which has developed a code package with a hierarchy of physics levels that resolve increasingly complete subsets of phase-spaces and are thus increasingly more realistic. The rationale for the multilevel physics models is given. Each physics level is described and examples of its application are given. The existing physics levels are fluid models (3D configuration space), namely magnetohydrodynamic (MHD) and two-fluids; and hybrid models, namely gyrokinetic-energetic-particle/MHD (5D energetic particle phase-space), gyrokinetic-particle-ion/fluid-electron (5D ion phase-space), and full-kinetic-particle-ion/fluid-electron level (6D ion phase-space). Resolving electron phase-space (5D or 6D) remains a future project. Phase-space-fluid models are not used in favor of delta f particle models. A practical and accurate nonlinear fluid closure for noncollisional plasmas seems not likely in the near future.

  18. Preface to Special Topic: Plasmas for Medical Applications

    NASA Astrophysics Data System (ADS)

    Keidar, Michael; Robert, Eric

    2015-12-01

    Intense research effort over last few decades in low-temperature (or cold) atmospheric plasma application in bioengineering led to the foundation of a new scientific field, plasma medicine. Cold atmospheric plasmas (CAP) produce various chemically reactive species including reactive oxygen species (ROS) and reactive nitrogen species (RNS). It has been found that these reactive species play an important role in the interaction of CAP with prokaryotic and eukaryotic cells triggering various signaling pathways in cells.

  19. Preface to Special Topic: Plasmas for Medical Applications

    SciTech Connect

    Keidar, Michael; Robert, Eric

    2015-12-15

    Intense research effort over last few decades in low-temperature (or cold) atmospheric plasma application in bioengineering led to the foundation of a new scientific field, plasma medicine. Cold atmospheric plasmas (CAP) produce various chemically reactive species including reactive oxygen species (ROS) and reactive nitrogen species (RNS). It has been found that these reactive species play an important role in the interaction of CAP with prokaryotic and eukaryotic cells triggering various signaling pathways in cells.

  20. Simultaneous determination of leucine, isoleucine and valine in Beagle dog plasma by HPLC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Wang, Ting; Xie, Huiru; Chen, Xu; Jiang, Xuehua; Wang, Ling

    2015-10-10

    Leucine (Leu), isoleucine (Ile) and valine (Val) are three branched-chain amino acids (BCAAs), which have been widely used as dietary supplements for professional athletes and patients with liver failure or catabolic diseases. To date, no pharmacokinetic studies of BCAAs in vivo useful for the assessment of clinical effect following daily intake has been reported. Thus in this study, an HPLC-MS/MS method for simultaneous determination of Leu, Ile and Val in Beagle dog plasma using homoarginine as the internal standard was developed and validated in terms of specificity, linearity, precision, accuracy, and stability. This assay method was then applied to a pharmacokinetic study of BCAAs in dogs following oral administration of 0.25 g/kg and 0.50 g/kg BCAAs. The HPLC-MS/MS method was found to be sensitive and reproducible for quantification of BCAAs in dog plasma and successfully applied to the pharmacokinetic study. All these BCAAs were well absorbed with a substantial increase in the plasma concentration after a baseline modification. No statistical significance was identified in different gender group and no drug accumulation was observed following multiple doses.

  1. Microwave imaging diagnostics for plasma fluctuation studies

    NASA Astrophysics Data System (ADS)

    Wang, Jian

    Electron Cyclotron Emission Imaging (ECEI) and Microwave Imaging Reflectometry (MIR) combined systems are being investigated by the UC Davis Plasma Diagnostic Group (PDG), in collaboration with Princeton Plasma Physics Laboratory (PPPL) researchers, Drs. E. Mazzucato, H.K. Park and T. Munsat, as well as researchers from the FOM-Instituut voor Plasmafysica Rijnhuizen,the Netherlands. The goal is to develop the plasma diagnostic systems based on the imaging technology developed in the UC Davis PDG group, for the study of plasma micro-turbulence, which is extremely important for the understanding of anomalous transport behavior of magnetically confined plasmas such as in tokamaks. This dissertation work provides the design of the optical systems, the design of the electronics, the testing of the antenna array and the data analysis of TEXTOR ECEI/MIR combined systems.

  2. Compact Plasma Accelerator for Micropropulsion Applications

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2001-01-01

    There is a need for a low power, light-weight (compact), high specific impulse electric propulsion device to satisfy mission requirements for microsatellite (1 to 20 kg) class missions. Satisfying these requirements entails addressing the general problem of generating a sufficiently dense plasma within a relatively small volume and then accelerating it. In the work presented here, the feasibility of utilizing a magnetic cusp to generate a dense plasma over small length scales of order 1 mm is investigated. This approach could potentially mitigate scaling issues associated with conventional ion thruster plasma containment schemes. Plume and discharge characteristics were documented using a Faraday probe and a retarding potential analyzer.

  3. Development, diagnostic and applications of radio-frequency plasma reactor

    NASA Astrophysics Data System (ADS)

    Puac, N.

    2008-07-01

    In many areas of the industry, plasma processing of materials is a vital technology. Nonequilibrium plasmas proved to be able to produce chemically reactive species at a low gas temperature while maintaining highly uniform reaction rates over relatively large areas (Makabe and Petrovic 2006). At the same time nonequilibrium plasmas provide means for good and precise control of the properties of active particles that determine the surface modification. Plasma needle is one of the atmospheric pressure sources that can be used for treatment of the living matter which is highly sensitive when it comes to low pressure or high temperatures (above 40 C). Dependent on plasma conditions, several refined cell responses are induced in mammalian cells (Sladek et al. 2005). It appears that plasma treatment may find many biomedical applications. However, there are few data in the literature about plasma effects on plant cells and tissues. So far, only the effect of low pressure plasmas on seeds was investigated. It was shown that short duration pretreatments by non equilibrium low temperature air plasma were stimulative in light induced germination of Paulownia tomentosa seeds (Puac et al. 2005). As membranes of plants have different properties to those of animals and as they show a wide range of properties we have tried to survey some of the effects of typical plasma which is envisaged to be used in biotechnological applications on plant cells. In this paper we will make a comparison between two configurations of plasma needle that we have used in treatment of biological samples (Puac et al. 2006). Difference between these two configurations is in the additional copper ring that we have placed around glass tube at the tip of the needle. We will show some of the electrical characteristics of the plasma needle (with and without additional copper ring) and, also, plasma emission intensity obtained by using fast ICCD camera.

  4. Helium Atmospheric Pressure Plasma Jet: Diagnostics and Application for Burned Wounds Healing

    NASA Astrophysics Data System (ADS)

    Topala, Ionut; Nastuta, Andrei

    A new field of plasma applications developed in the last years, entitled plasma medicine, has focused the attention of many peoples from plasma ­community on biology and medicine. Subjects that involve plasma physics and technology (e.g. living tissue treatment or wound healing, cancer cell apoptosis, blood coagulation, sterilization and decontamination) are nowadays in study in many laboratories. In this paper we present results on optical and electrical diagnosis of a helium ­atmospheric pressure plasma jet designed for medical use. This type of plasma jet was used for improvement of the wound healing process. We observed a more rapid macroscopic healing of the plasma treated wounds in comparison with the control group.

  5. Highly selective enrichment of baicalin in rat plasma by boronic acid-functionalized core-shell magnetic microspheres: Validation and application to a pharmacokinetic study.

    PubMed

    Huang, Taomin; Xiong, Ya; Chen, Nianzu; Wang, Donglei; Lai, Yonghua; Deng, Chunhui

    2016-01-15

    To the best of our knowledge, this study is the first to successfully apply a novel, highly selective enrichment technique based on boronic acid-functionalized core-shell magnetic microspheres (BA-Fe3O4@SiO2-Au@mSiO2) with a large surface area and uniform pore size, to determine the baicalin concentration in rat plasma by HPLC. By taking advantage of the special interaction between boronic acid and baicalin under alkaline conditions, as well as the microspheres' size exclusion ability, baicalin was selectively extracted from protein-rich biosamples, such as plasma, without any other pretreatment procedure except for a 10-min vortexing step. BA-Fe3O4@SiO2-Au@mSiO2 microsphere-adsorbed baicalin was straightforwardly and rapidly isolated from the matrix using a magnet. Baicalin was subsequently eluted from the microspheres under acidic conditions for 2min for further HPLC analysis. The extraction conditions, such as the amount of microspheres added, adsorption time, adsorption pH, and elution time and pH, were also determined. Furthermore, method validation, including the linear range, detection limit, precision, accuracy, and recovery, were determined. This newly developed method based on BA-Fe3O4@SiO2-Au@mSiO2 microspheres is a simple, accurate, selective, and green analytical preparatory technique for analyzing baicalin in rat plasma. This study will be further novel research on the analysis of complex plasma samples and the pharmacokinetics of drugs similar to baicalin.

  6. Validated method to measure yakuchinone A in plasma by LC-MS/MS and its application to a pharmacokinetic study in rats

    PubMed Central

    2014-01-01

    Background Yakuchinone A has a plethora of beneficial biological effects. However, the pharmacokinetic (PK) data of yakuchinone A still remain unknown so far. Furthermore, the quantification of yakuchinone A in biological samples has not been reported in the literature. Therefore, in the present study we aimed to develop a new method for the fast, efficient and accurate assessment of yakuchinone A concentration in plasma, as a means for facilitating the PK evaluation of yakuchinone A. Results A liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for the determination of yakuchinone A in rat plasma. Mass spectrometric and chromatographic conditions were optimized. Plasma samples were pretreated by protein precipitation with methanol. LC separation was performed on a Phenomenex Luna C18 column with gradient elution using a mobile phase consisting of methanol–water containing 0.5 mM formic acid (HCOOH) at a flow rate of 0.28 mL/min. ESI-MS spectra were acquired in positive ion multiple reaction monitoring mode (MRM). The precursor-to-product ion pairs used for MRM of yakuchinone A and yakuchinone B were m/z 313.1 → 137.0 and 311.2 → 117.1, respectively. Low concentration of HCOOH reduced the ion suppression caused by matrix components and clearly improved the analytical sensitivity. Yakuchinone A showed good linearity over a wide concentration range (r > 0.99). The accuracy, precision, stability and linearity were found to be within the acceptable criteria. This new method was successfully applied to analyze the rat plasma concentration of parent yakuchinone A after a single oral administration of SuoQuan capsules. Low systemic exposure to parent yakuchinone A was observed. Conclusion The proposed method is sensitive and reliable. It is hoped that this new method will prove useful for the future PK studies. PMID:24422995

  7. Rapid, sensitive and selective HPLC-MS/MS method for the quantification of topically applied besifloxacin in rabbit plasma and ocular tissues: Application to a pharmacokinetic study.

    PubMed

    Gu, Xiao-Fei; Mao, Bai-Yang; Xia, Min; Yang, Yang; Zhang, Jia-Li; Yang, Da-Song; Wu, Wei-Xin; Du, Ying-Xiang; Di, Bin; Su, Meng-Xiang

    2016-01-01

    Besifloxacin is a fourth-generation broad-spectrum fluoroquinolone registered for the topical treatment of bacterial conjunctivitis. In this study, a rapid, sensitive and selective liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for quantification of besifloxacin in rabbit plasma and ocular tissues using nateglinide as the internal standard (IS). The analyte and IS were separated on a Sepax GP-Phenyl column by isocratic elution with methanol-acetonitrile-5 mM ammonium formate-formic acid (29:55:16:0.1, v/v/v/v) as the mobile phase at a flow rate of 1.2 mL/min, and the total run time was 3.0 min. An electrospray ionization (ESI) source was applied and operated in the positive ion mode; multiple reaction monitoring (MRM) mode was used for quantification, and the monitored transitions were 394.2→377.1 for besifloxacin and m/z 318.3→166.1 for the IS. The calibration curve was linear over the range of 0.103-206 ng/mL for plasma and 2.06-2060 ng/mL for tears, aqueous humor, conjunctiva and cornea with correlation coefficient (r) greater than 0.99. The lower limit of quantification (LLOQ) for besifloxacin was 0.103 ng/mL for plasma and 2.06 ng/mL for other ocular tissues with good accuracy and precision. Intra- and inter-batch precision were both lower than 15% and accuracy ranged from 85% to 115% at all QC levels. The method was successfully applied to the pharmacokinetic study of besifloxacin in rabbit plasma and ocular tissues after single and multiple topical administrations. PMID:26340560

  8. Coblation technology: plasma-mediated ablation for otolaryngology applications

    NASA Astrophysics Data System (ADS)

    Woloszko, Jean; Gilbride, Charles

    2000-05-01

    Coblation is a unique method of delivering radio frequency energy to soft tissue for applications in Otolaryngology (ENT). Using radio frequency in a bipolar mode with a conductive solution, such as saline, Coblation energizes the ions in the saline to form a small plasma field. The plasma has enough energy to break the tissue's molecular bonds, creating an ablative path. The thermal effect of this process is approximately 45 - 85 degrees Celsius, significantly lower than traditional radio-frequency techniques. Coblation has been used for Otolaryngological applications such as Uvulopalatopharyngoplasty (UPPP), tonsillectomy, turbinate reduction, palate reduction, base of tongue reduction and various Head and Neck cancer procedures. The decreased thermal effect of Coblation anecdotally has led to less pain and faster recovery for cases where tissue is excised. In cases where Coblation is applied submucosally to reduce tissue volume (inferior turbinate, soft palate), the immediate volume reduction may lead to immediate clinical benefits for the patient. Coblation is currently being tested in various clinical studies to document the benefits for otolaryngological applications.

  9. Air Plasma Source for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Henriques, J.; Tatarova, E.; Dias, F. M.; Ferreira, C. M.; Gordiets, B.; IPFN-IST, 1049-001 LX, Portugal Team; Lebedev Physical Institute of the Russian Academy of Sciences Team

    2011-10-01

    Plasma interactions with living matter are presently at the frontiers of plasma research and development. Plasmas contain numerous agents that influence biological activity. They provide essentially two types of biocidal species: reactive species, such as oxygen atoms that lead to lethality of micro-organisms through erosion, and UV radiation that can damage the DNA strands. In this work we investigate a surface wave (2.45 GHz) driven discharge plasma in air, with a small admixture of water vapor, as a source of ground state O(3P) oxygen atoms, NO molecules and UV radiation. A theoretical model describing both the wave driven discharge zone and its flowing afterglow is used to analyze the performance of this plasma source. The predicted plasma-generated NO(X) and O(3P) concentrations and NO(γ) radiation intensity along the source are presented and discussed as a function of the microwave power and water vapor percentage in the gas mixture. To validate the theoretical predictions, the relative concentrations of species have been determined by Mass Spectrometry, Fourier Transform Infrared Spectroscopy and Optical Spectroscopy. Acknowledgment: This work was funded by the Portuguese Foundation for Science and Technology, under research contract PTDC/FIS/108411/2008.

  10. Plasma characterization studies for materials processing

    SciTech Connect

    Pfender, E.; Heberlein, J.

    1995-12-31

    New applications for plasma processing of materials require a more detailed understanding of the fundamental processes occurring in the processing reactors. We have developed reactors offering specific advantages for materials processing, and we are using modeling and diagnostic techniques for the characterization of these reactors. The emphasis is in part set by the interest shown by industry pursuing specific plasma processing applications. In this paper we report on the modeling of radio frequency plasma reactors for use in materials synthesis, and on the characterization of the high rate diamond deposition process using liquid precursors. In the radio frequency plasma torch model, the influence of specific design changes such as the location of the excitation coil on the enthalpy flow distribution is investigated for oxygen and air as plasma gases. The diamond deposition with liquid precursors has identified the efficient mass transport in form of liquid droplets into the boundary layer as responsible for high growth, and the chemical properties of the liquid for the film morphology.

  11. A strategy for extending the applicability of a validated plasma calibration curve to quantitative measurements in multiple tissue homogenate samples: a case study from a rat tissue distribution study of JI-101, a triple kinase inhibitor.

    PubMed

    Gurav, Sandip Dhondiram; Jeniffer, Sherine; Punde, Ravindra; Gilibili, Ravindranath Reddy; Giri, Sanjeev; Srinivas, Nuggehally R; Mullangi, Ramesh

    2012-04-01

    A general practice in bioanalysis is that, whatever the biological matrix the analyte is being quantified in, the validation is performed in the same matrix as per regulatory guidelines. In this paper, we are presenting the applicability of a validated LC-MS/MS method in rat plasma for JI-101, to estimate the concentrations of JI-101 in various tissues that were harvested in a rat tissue distribution study. A simple protein precipitation technique was used to extract JI-101 and internal standard from the tissue homogenates. The recovery of JI-101 in all the matrices was found to be >70%. Chromatographic separation was achieved using a binary gradient using mobile phase A (acetonitrile) and B (0.2% formic acid in water) at a flow rate of 0.30 mL/min on a Prodigy ODS column with a total run time of 4.0 min. The MS/MS ion transitions monitored were 466.1 → 265 for JI-101 and 180.1 → 110.1 for internal standard. The linearity range was 5.02-4017 ng/mL. The JI-101 levels were quantifiable in the various tissue samples harvested in this study. Therefore, the use of a previously validated JI-101 assay in plasma circumvented the tedious process of method development/validation in various tissue matrices.

  12. Simple, sensitive and rapid LC-MS method for the quantitation of indapamide in human plasma--application to pharmacokinetic studies.

    PubMed

    Chen, Wei-Dong; Liang, Yan; Zhang, Hong; Li, Hao; Xiong, Ye; Wang, Guang-Ji; Xie, Lin

    2006-09-14

    A sensitive and specific method using liquid chromatography with electrospray ionization mass spectrometry (LC-ESI-MS) has been developed and validated for the identification and quantification of indapamide in human plasma. A simple liquid-liquid extraction procedure was followed by injection of the extracts on to a C18 column with gradient elution and detection using a single quadrupole mass spectrometer in selected ion monitoring (SIM) mode. The method was tested using six different plasma batches. Linearity was established for the concentration range 0.5-100.0 ng/ml, with a coefficient of determination (r) of 0.9998 and good back-calculated accuracy and precision. The intra- and inter-day precision (RSD%) was lower than 10%, and accuracy ranged from 85 to 115%. The lower limit of quantification was reproducible at 0.2 ng/ml with 0.2 ml plasma. The proposed method enables the unambiguous identification and quantification of indapamide for pre-clinical and clinical studies. PMID:16843739

  13. Determination of Doxorubicin in Stealth Hyalurionic Acid-Based Nanoparticles in Rat Plasma by the Liquid-Liquid Nanoparticles-Breaking Extraction Method: Application to a Pharmacokinetic Study.

    PubMed

    Han, Xiaopeng; Wei, Wei; Zhong, Lu; Luo, Cong; Wu, Chunnuan; Jiang, Qikun; Sun, Jin

    2016-09-01

    An efficient extraction of doxorubicin (Dox) from homemade stealth hyalurionic acid (HA)-based nanoparticles (NPs) in rat plasma could not be performed by previously published methods. Therefore, we attempted to establish the novel NPs-breaking and UPLC-MS-MS method for evaluating the pharmacokinetic profiles of the homemade stealth HA NPs in rats. The pretreatment method of plasma samples used the liquid-liquid extraction method with isopropyl alcohol as NPs-breaking and protein-precipitating solvents, and the NPs-breaking efficiency of isopropyl alcohol was as high as 97.2%. The analyte and gliclazide (internal standard) were extracted from plasma samples with isopropyl alcohol and were separated on UPLC BEH C18 with a mobile phase consisting of methanol and water (containing 0.1% formic acid). The method demonstrated good linearity at the concentrations ranging from 5 to 5,000 ng/mL. The intra- and interday relative standard deviations were >10%. Finally, the method was successfully applied to a pharmacokinetic study of homemade stealth HA-based NPs in rats following intravenous administration.

  14. Quantification of sofosbuvir and ledipasvir in human plasma by UPLC-MS/MS method: Application to fasting and fed bioequivalence studies.

    PubMed

    Rezk, Mamdouh R; Bendas, Ehab R; Basalious, Emad B; Karim, Iman A

    2016-08-15

    A rapid and sensitive LC-MS/MS method was developed, optimized and validated for quantification of sofosbuvir (SF) and ledipasvir (LD) in human plasma using eplerenone as an internal standard (IS). Analytes and IS were extracted from plasma by simple liquid-liquid extraction technique using methyl tertiary butyl ether. The prepared samples were chromatographed on Acquity UPLC BEH C18 column. Separation was done using a mobile phase formed of 0.1% formic acid and acetonitrile (50:50, v/v) in an isocratic mode at a flow rate of 0.4ml/min. The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. A full validation of the method was performed according to the FDA guidelines. Linearity was found to be in the range of 0.25-3500ng/ml for SF and 5-2000ng/ml for LD. The intra-day and inter-day precision and accuracy results were within the acceptable limits. A short run time of 2min allows analysis of more than 400 plasma samples per day. The developed method was successfully applied to both fasting and fed bioequivalence studies in healthy human volunteers. PMID:27322631

  15. Determination of cefadroxil in rat plasma and urine using LC-MS/MS and its application to pharmacokinetic and urinary excretion studies.

    PubMed

    Jin, Hyo-Eon; Kim, In-Bong; Kim, Yu Chul; Cho, Kwan Hyung; Maeng, Han-Joo

    2014-02-01

    A simple, rapid, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of cefadroxil, a first-generation cephalosporin, in rat plasma and urine. Rat samples were deproteinized with methanol, and then injected into the LC-MS/MS system (electro-spray ionization, positive mode) for quantification. Drugs were separated on a Synergi™ 4 μm Polar-RP 80A column (150 mm × 2.0 mm, 4 μm) with a mixture of 0.1% formic acid and methanol (62:38, v/v) as the mobile phase at 0.2 mL/min. Detection was performed using multiple reaction-monitoring modes at m/z 364.1→208.1 (for cefadroxil) and m/z 368.1→174.2 (for cefaclor, the internal standard). Method was specific and linear over the concentration range of 10-10,000 ng/mL. Validation parameters for cefadroxil, including accuracy, precision, absolute matrix effect, and stability in rat plasma and urine, were acceptable according to the biological method validation guidelines of the FDA (2001) [16]. Cefadroxil levels in plasma up to 1440 min or 480 min and urine up to 96 h were quantifiable following oral and intravenous cefadroxil administrations to rats at a dose of 2mg/kg, each, suggesting that the method is appropriate for routine pharmacokinetic studies including urinary recovery in rats.

  16. Concurrent determination of olanzapine, risperidone and 9-hydroxyrisperidone in human plasma by ultra performance liquid chromatography with diode array detection method: application to pharmacokinetic study.

    PubMed

    Siva Selva Kumar, M; Ramanathan, M

    2016-02-01

    A simple and sensitive ultra-performance liquid chromatography (UPLC) method has been developed and validated for simultaneous estimation of olanzapine (OLZ), risperidone (RIS) and 9-hydroxyrisperidone (9-OHRIS) in human plasma in vitro. The sample preparation was performed by simple liquid-liquid extraction technique. The analytes were chromatographed on a Waters Acquity H class UPLC system using isocratic mobile phase conditions at a flow rate of 0.3 mL/min and Acquity UPLC BEH shield RP18 column maintained at 40°C. Quantification was performed on a photodiode array detector set at 277 nm and clozapine was used as internal standard (IS). OLZ, RIS, 9-OHRIS and IS retention times were found to be 0.9, 1.4, .1.8 and 3.1 min, respectively, and the total run time was 4 min. The method was validated for selectivity, specificity, recovery, linearity, accuracy, precision and sample stability. The calibration curve was linear over the concentration range 1-100 ng/mL for OLZ, RIS and 9-OHRIS. Intra- and inter-day precisions for OLZ, RIS and 9-OHRIS were found to be good with the coefficient of variation <6.96%, and the accuracy ranging from 97.55 to 105.41%, in human plasma. The validated UPLC method was successfully applied to the pharmacokinetic study of RIS and 9-OHRIS in human plasma.

  17. Validated RP-HPLC/UV method for the quantitation of abiraterone in rat plasma and its application to a pharmacokinetic study in rats.

    PubMed

    Kumar, S Vijay; Rudresha, G; Gurav, Sandip; Zainuddin, Mohd; Dewang, Purushottam; Kethiri, Raghava Reddy; Rajagopal, Sriram; Mullangi, Ramesh

    2013-02-01

    A novel, simple, specific, sensitive and reproducible high-performance liquid chromatography (HPLC) assay method has been developed and validated for the estimation of abiraterone (ART) in rat plasma. The analytical procedure involves extraction of ART and diclofenac (internal standard, IS) from rat plasma with a simple liquid-liquid extraction process. The chromatographic analysis was performed on a Waters Alliance system with a Betasil C(18) column maintained at ambient room temperature and an isocratic mobile phase [acetonitrile-water-10 mm potassium dihydrogen phosphate (pH 3.0), 55:5:40, v/v/v] at a flow rate of 1.00 mL/min with a total run time of 10 min. The eluate was monitored using an UV detector set at 255 nm. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 93.4-3251 ng/mL (r(2) = 0.997). The intra- and inter-day precisions were 0.56-4.98 and 3.03-7.18, respectively, in rat plasma. The validated HPLC method was successfully applied to a pharmacokinetic study of ART in rats.

  18. Development of a selective and fast LC-MS/MS for determination of WSJ-537, an xanthine oxidase inhibitor, in rat plasma: Application to a pharmacokinetic study.

    PubMed

    Lin, Jianyang; Yang, Tian; Zhang, Donghu

    2016-08-15

    Gout is a common metabolic disorder caused by the deposition of monosodium urate crystals within joints. A new kind of xanthine oxidase inhibitor, WSJ-537, was developed as a potential drug. In order to investigate the pharmacokinetic behavior in vivo, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for determination the concentration of WSJ-537 in rat plasma was developed. After extraction by protein precipitation method with acetonitrile, the chromatographic separation was accomplished on a Venusil ASB C18 column(2.1mm×50mm, 3mm)at a flow rate of 0.3mLmin(-1) with the mobile phase consisting of acetonitrile-ammonium acetate (33:67, v/v). An electrospray ionization (ESI) source was applied and operated in the positive ion mode. The plasma concentration was detected by multiple reactions monitoring (MRM) mode with the target fragment ions m/z 410.2→m/z 368.1 for WSJ-537 and m/z 244.1→m/z 185.0 for the IS. Good linearity was observed in the range of 20-800ngmL(-1) (r=0.9947). The recovery of WSJ-537 in rats plasma was more than 85%. This method was suitable for pharmacokinetic studies after oral administration of 10mg/kg WSJ-537 in rats. PMID:27322629

  19. Study of metallic powder behavior in very low pressure plasma spraying (VLPPS) — Application to the manufacturing of titanium–aluminum coatings

    SciTech Connect

    Vautherin, B.; Planche, M.-P.; Montavon, G.; Lapostolle, F.; Quet, A.; Bianchi, L.

    2015-08-28

    In this study, metallic materials made of aluminum and titanium were manufactured implementing very low pressure plasma spraying (VLPPS). Aluminum was selected at first as a demonstrative material due to its rather low vaporization enthalpy (i.e., 381.9 kJ·mol⁻¹). Developments were then carried out with titanium which exhibits a higher vaporization enthalpy (i.e., 563.6 kJ·mol⁻¹). Optical emission spectroscopy (OES) was implemented to analyze the behavior of each solid precursor (metallic powders) when it is injected into the plasma jet under very low pressure (i.e., in the 150 Pa range). Besides, aluminum, titanium and titanium–aluminum coatings were deposited in the same conditions implementing a stick-cathode plasma torch operated at 50 kW, maximum power. Coating phase compositions were identified by X-Ray Diffraction (XRD). Coating elementary compositions were quantified by Glow Discharge Optical Emission Spectroscopy (GDOES) and Energy Dispersive Spectroscopy (EDS) analyses. The coating structures were observed by Scanning Electron Microscopy (SEM). The coating void content was determined by Ultra-Small Angle X-ray Scattering (USAXS). The coatings exhibit a two-scale structure corresponding to condensed vapors (smaller scale) and solidified areas (larger scale). Titanium–aluminum sprayed coatings, with various Ti/Al atomic ratios, are constituted of three phases: metastable α-Ti, Al and metastable α₂-Ti₃Al. This latter is formed at elevated temperature in the plasma flow, before being condensed. Its rather small fraction, impeded by the rather small amount of vaporized Ti, does not allow modifying however the coating hardness.

  20. Determination of secnidazole in human plasma by high-performance liquid chromatography with UV detection and its application to the bioequivalence studies.

    PubMed

    Li, Xiaoyu; Sun, Jianguo; Wang, Guangji; Zheng, Yuanting; Yan, Bei; Xie, Haitang; Gu, Yi; Ren, Hongchan

    2007-03-01

    A simple, accurate, precise and sensitive HPLC-UV method was developed for the determination of secnidazole in human plasma. Secnidazole and tinidazole (IS) were extracted from 0.2 mL of human plasma by ethyl acetate. Secnidazole was then separated by HPLC on a Diamond C(18) column and quantified by ultraviolet detection at 319 nm. The mobile phase consisted of acetonitrile-aqueous 5 mm sodium acetate (30:70, v/v) containing of 0.1% acetic acid adjusted to pH 4.0, and the flow rate was 1.0 mL/min. The low limit of quantification was 0.1 microg/mL. The method was linear over the concentration range 0.1-25.0 microg/mL (R(2) = 1.000). The recovery of secnidazole from human plasma ranged from 76.5 to 89.1%. Inter- and intra-assay precision ranged from 3.3 to 10.7%. Secnidazole in plasma was stable when stored at ambient temperature for 8 h, at -20 degrees C for 2 weeks and at -20 degrees C for three freeze-thaw cycles. The developed method was successfully applied to the pharmacokinetic and bioequivalence studies between test and reference secnidazole tablets following a single 500 mg oral dosage to 20 healthy volunteers of both genders. Pharmacokinetics parameters T(max), C(max), AUC(0-)t, AUC(0-infinity), T(1/2) were determined of both preparations. The analysis of variance (ANOVA) did not show any significant difference between the two preparations and 90% confidence intervals fell within the acceptable range for bioequivalence. It was concluded that the two secnidazole preparations are bioequivalence and may be used interchangeably. PMID:17221933

  1. Quantitative determination of isorhamnetin, quercetin and kaempferol in rat plasma by liquid chromatography with electrospray ionization tandem mass spectrometry and its application to the pharmacokinetic study of isorhamnetin.

    PubMed

    Lan, Ke; Jiang, Xuehua; He, Jianling

    2007-01-01

    A simple and sensitive liquid chromatography/tandem mass spectrometry method was developed and validated for the quantification of quercetin, kaempferol and isorhamnetin in rat plasma. After being treated with beta-glucuronidase and sulfatase, the analytes were extracted by liquid/liquid extraction with the internal standard (IS; baicalein). The chromatographic separation was performed on a Diamonsil C(18) column with a mobile phase consisting of 2% formic acid/methanol (10:90, v/v) at a flow rate of 1.00 mL/min, with a split of 200 microL to the mass spectrometer. Validation results indicated that the lower limit of quantification (LLOQ) was 1 ng . mL(-1). The assay exhibited a linear range of 1-200 ng . mL(-1) and gave a correlation coefficient of 0.9980 or better for each analyte. Quality control samples (1, 5, 20 and 100 ng . mL(-1)) in six replicates from each of three different runs demonstrated an intra-assay precision (RSD) of 1.1-8.9%, an inter-assay precision of 1.6-10.8%, and an overall accuracy (bias) of <13.4%. The extraction recovery of each analyte and internal standard was 70-80%. In the present study, we have investigated the pharmacokinetic profiles of isorhamnetin after oral application in rats equipped with a jugular catheter. After oral dosing of isorhamnetin, the mean values (n = 10) of C(max) were 57.8, 64.8 and 75.2 ng . mL(-1) which were achieved at a T(max) of 8.0, 6.4 and 7.2 h for oral doses of 0.25, 0.5 and 1.0 mg . kg(-1) body weight, respectively. The corresponding mean values for isorhamnetin area under the curver (AUC) from 0 to 60 h were 838.2, 1262.8, 1623.4 ng . h . mL(-1). Our results further demonstrated that the samples analyzed showed isorhamnetin could not be transformed into quercetin or kaempferol in rats, indicating that the demethylation of the 3'-oxymethyl group of isorhamnetin does not occur in Wistar rats. PMID:17154349

  2. Surface studies of plasma processed Nb samples

    SciTech Connect

    Tyagi, Puneet V; Doleans, Marc; Hannah, Brian S; Afanador, Ralph; Stewart, Stephen; Mammosser, John; Howell, Matthew P; Saunders, Jeffrey W; Degraff, Brian D; Kim, Sang-Ho

    2015-01-01

    Contaminants present at top surface of superconducting radio frequency (SRF) cavities can act as field emitters and restrict the cavity accelerating gradient. A room temperature in-situ plasma processing technology for SRF cavities aiming to clean hydrocarbons from inner surface of cavities has been recently developed at the Spallation Neutron Source (SNS). Surface studies of the plasma processed Nb samples by Secondary ion mass spectrometry (SIMS) and Scanning Kelvin Probe (SKP) showed that the NeO2 plasma processing is very effective to remove carbonaceous contaminants from top surface and improves the surface work function by 0.5 to 1.0 eV.

  3. Dust Particle Growth and Application in Low Temperature Plasmas

    SciTech Connect

    Boufendi, L.

    2008-09-23

    Dust particle nucleation and growth has been widely studied these last fifteen years in different chemistries and experimental conditions. This phenomenon is correlated with various electrical changes at electrodes, including self-bias voltage and amplitudes of the various harmonics of current and voltage [1]. Some of these changes, such as the appearance of more resistive plasma impedance, are correctly attributed to loss of electrons in the bulk plasma to form negative molecular ions (e.g. SiH{sub 3}{sup -}) and more precisely charged nanoparticles. These changes were studied and correlated to the different phases on the dust particle formation. It is well known now that, in silane argon gas mixture discharges, in the first step of this particle formation we have formation of nanometer sized crystallites. These small entities accumulate and when their number density reaches a critical value, about 10{sup 11} to 10{sup 12} cm{sup -1}, they start to aggregate to form bigger particles. The different phases are well defined and determined thanks to the time evolution of the different electrical parameter changes. The purpose of this contribution is to compare different chemistries to highlight similarities and/or differences in order to establish possible universal dust particle growth mechanisms. The chemistries we studied concern SiH{sub 4}-Ar, CH{sub 4}, CH{sub 4}-N{sub 2} and Sn(CH{sub 3}){sub 4}[2]. We also refer to works performed in other laboratories in different discharge configurations [3]. Different applications have already developed or are foreseen for these nanoparticles. The first application concerns the inclusion of nanosized dust crystallites in an amorphous matrix in order to modify the optoelectronic and mechanical properties [4-5]. At the present time a very active research programs are devoted towards single electron devises where nanometer sized crystallites play a role of quantum dots. These nanoparticles can be produced in low pressure cold

  4. Experimental study of the plasma window

    NASA Astrophysics Data System (ADS)

    Shi, Ben-Liang; Huang, Sheng; Zhu, Kun; Lu, Yuan-Rong

    2014-01-01

    The plasma window is an advanced apparatus that can work as the interface between a vacuum and a high pressure region. It can be used in many applications that need atmosphere-vacuum interface, such as a gas target, electron beam welding, synchrotron radiation and a spallation neutron source. A test bench of the plasma window is constructed in Peking University. A series of experiments and the corresponding parameter measurements have been presented in this article. The experiment result indicates the feasibility of such a facility acting as an interface between a vacuum and a high pressure region.

  5. Plasma process optimization for N-type doping applications

    NASA Astrophysics Data System (ADS)

    Raj, Deven; Persing, Harold; Salimian, Siamak; Lacey, Kerry; Qin, Shu; Hu, Jeff Y.; McTeer, Allen

    2012-11-01

    Plasma doping (PLAD) has been adopted across the implant technology space and into high volume production for both conventional DRAM and NAND doping applications. PLAD has established itself as an alternative to traditional ion implantation by beamline implantation. The push for high doping concentration, shallow doping depth, and conformal doping capability expand the need for a PLAD solution to meet such requirements. The unique doping profile and doping characteristics at high dose rates allow for PLAD to deliver a high throughput, differentiated solution to meet the demand of evolving transistor technology. In the PLAD process, ions are accelerated to the wafer as with a negative wafer bias applied to the wafer. Competing mechanisms, such as deposition, sputtering, and etching inherent in plasma doping require unique control and process optimization. In this work, we look at the distinctive process tool control and characterization features which enable an optimized doping process using n-type (PH3 or AsH3) chemistries. The data in this paper will draw the relationship between process optimization through plasma chemistry study to the wafer level result.

  6. Plasma process optimization for N-type doping applications

    SciTech Connect

    Raj, Deven; Persing, Harold; Salimian, Siamak; Lacey, Kerry; Qin Shu; Hu, Jeff Y.; McTeer, Allen

    2012-11-06

    Plasma doping (PLAD) has been adopted across the implant technology space and into high volume production for both conventional DRAM and NAND doping applications. PLAD has established itself as an alternative to traditional ion implantation by beamline implantation. The push for high doping concentration, shallow doping depth, and conformal doping capability expand the need for a PLAD solution to meet such requirements. The unique doping profile and doping characteristics at high dose rates allow for PLAD to deliver a high throughput, differentiated solution to meet the demand of evolving transistor technology. In the PLAD process, ions are accelerated to the wafer as with a negative wafer bias applied to the wafer. Competing mechanisms, such as deposition, sputtering, and etching inherent in plasma doping require unique control and process optimization. In this work, we look at the distinctive process tool control and characterization features which enable an optimized doping process using n-type (PH{sub 3} or AsH{sub 3}) chemistries. The data in this paper will draw the relationship between process optimization through plasma chemistry study to the wafer level result.

  7. Plasma mass filtering techniques: applications and requirements

    NASA Astrophysics Data System (ADS)

    Gueroult, Renaud; Fisch, Nathaniel J.

    2013-10-01

    Plasma mass filters differ from conventional chemical filtering techniques in that elements are dissociated, and can therefore be processed without regard to chemical form. In addition, plasma filters can be in principle operated at larger velocities compared to their gaseous and/or liquid counterparts, so that larger throughputs are possible. On the other hand, one has to pay the price of ionization, which sets a lower limit for the processing cost. Plasma mass filtering techniques are consequently foreseen as a promising solution for separation processes which are simultaneously chemically challenging and of high added value. Such separation processes can be, for example, found within the context of nuclear waste remediation, or nuclear spent fuel reprocessing. However, although plasma separation techniques appear globally attractive for these distinct needs, the plasma parameters required to fulfill a particular separation process are expected to depend strongly on the process's attributes (volume, composition, mass difference), which may vary significantly. Such operating parameters' variations are shown to be well accommodated by a particular configuration, called the Magnetic Centrifugal Mass Filter. Work supported by US DOE under contract Nos DE-AC02-09CH11466 and DE-FG02-06ER54851.

  8. Laboratory study of avalanches in magnetized plasmas.

    PubMed

    Van Compernolle, B; Morales, G J; Maggs, J E; Sydora, R D

    2015-03-01

    It is demonstrated that a novel heating configuration applied to a large and cold magnetized plasma allows the study of avalanche phenomena under controlled conditions. Intermittent collapses of the plasma pressure profile, associated with unstable drift-Alfvén waves, exhibit a two-slope power-law spectrum with exponents near -1 at lower frequencies and in the range of -2 to -4 at higher frequencies. A detailed mapping of the spatiotemporal evolution of a single avalanche event is presented.

  9. Applications of plasma core reactors to terrestrial energy systems

    NASA Technical Reports Server (NTRS)

    Latham, T. S.; Biancardi, F. R.; Rodgers, R. J.

    1974-01-01

    Plasma core reactors offer several new options for future energy needs in addition to space power and propulsion applications. Power extraction from plasma core reactors with gaseous nuclear fuel allows operation at temperatures higher than conventional reactors. Highly efficient thermodynamic cycles and applications employing direct coupling of radiant energy are possible. Conceptual configurations of plasma core reactors for terrestrial applications are described. Closed-cycle gas turbines, MHD systems, photo- and thermo-chemical hydrogen production processes, and laser systems using plasma core reactors as prime energy sources are considered. Cycle efficiencies in the range of 50 to 65 percent are calculated for closed-cycle gas turbine and MHD electrical generators. Reactor advantages include continuous fuel reprocessing which limits inventory of radioactive by-products and thorium-U-233 breeder configurations with about 5-year doubling times.-

  10. Final technical report on studies of plasma transport

    SciTech Connect

    O`Neil, T.M.; Driscoll, C.F.; Malmberg, J.H.

    1997-04-01

    This document gives an overview of the scientific results obtained under the DOE grant, and references the journal articles which give more complete descriptions of the various topics. Recently, the research has been focused on 2-dimensional vortices and turbulence: experiments using a new camera-diagnosed electron plasma apparatus have given surprising results which both clarify and challenge theories. Here, the crossfield E x B flow of the electron plasma is directly analogous to the 2-d flow of an ideal fluid such as water, and may also give insight into more complicated poloidal flows exhibited in toroidal plasmas. The shear-flow instabilities, turbulence, and vortices can be accurately observed, and the free relaxation of this turbulence has been characterized. The physical processes underlying the complicated turbulent evolution can also be studied in more controlled near-linear regimes. The original experimental focus of this program was on radial particle transport from applied external field asymmetries. Here, this research program clearly identified the importance of the collective response of the plasma, giving smaller fields from shielding, or enhanced fields from resonant modes. Experiments and theory work have also elucidated the flow of a plasma along the magnetic field. Finally, some theory was pursued for direct application to fusion plasmas, and to gravitating gas clouds in astrophysics. This program was highly successful in clarifying basic plasma transport processes.

  11. Surface Plasma Arc by Radio-Frequency Control Study (SPARCS)

    SciTech Connect

    Ruzic, David N.

    2013-04-29

    This paper is to summarize the work carried out between April 2012 and April 2013 for development of an experimental device to simulate interactions of o -normal detrimental events in a tokamak and ICRF antenna. The work was mainly focused on development of a pulsed plasma source using theta pinch and coaxial plasma gun. This device, once completed, will have a possible application as a test stand for high voltage breakdown of an ICRF antenna in extreme events in a tokamak such as edge-localized modes or disruption. Currently, DEVeX does not produce plasma with high temperature enough to requirement for an ELM simulator. However, theta pinch is a good way to produce high temperature ions. The unique characteristic of plasma heating by a theta pinch is advantageous for an ELM simulator due to its effective ion heating. The objective of the proposed work, therefore, is to build a test facility using the existing theta pinch facility in addition to a coaxial plasma gun. It is expected to produce a similar pulsed-plasma heat load to the extreme events in tokamaks and to be applied for studying interactions of hot plasma and ICRF antennas.

  12. Numerical Studies of Impurities in Fusion Plasmas

    DOE R&D Accomplishments Database

    Hulse, R. A.

    1982-09-01

    The coupled partial differential equations used to describe the behavior of impurity ions in magnetically confined controlled fusion plasmas require numerical solution for cases of practical interest. Computer codes developed for impurity modeling at the Princeton Plasma Physics Laboratory are used as examples of the types of codes employed for this purpose. These codes solve for the impurity ionization state densities and associated radiation rates using atomic physics appropriate for these low-density, high-temperature plasmas. The simpler codes solve local equations in zero spatial dimensions while more complex cases require codes which explicitly include transport of the impurity ions simultaneously with the atomic processes of ionization and recombination. Typical applications are discussed and computational results are presented for selected cases of interest.

  13. Development and validation of an UPLC-MS/MS method for the quantification of ethoxzolamide in plasma and bioequivalent buffers: Applications to absorption, brain distribution, and pharmacokinetic studies

    PubMed Central

    Gao, Song; Zhao, Jing; Yin, Taijun; Ma, Yong; Xu, Beibei; Moore, Anthony N.; Dash, Pramod K.; Hu, Ming

    2015-01-01

    The purpose of this study is to develop and validate an UPLC-MS/MS method to quantify ethoxzolamide in plasma (EZ) and apply the method to absorption, brain distribution, as well as pharmacokinetic studies. A C18 column was used with 0.1% of formic acid in acetonitrile and 0.1% of formic acid in water as the mobile phases to resolve EZ. The mass analysis was performed in a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) with positive scan mode. The results show that the linear range of EZ is 4.88–10,000.00 nM. The intra-day variance is less than 12.43 % and the accuracy is between 88.88–08.00 %. The inter-day variance is less than 12.87 % and accuracy is between 89.27–115.89 %. Protein precipitation was performed using methanol to extract EZ from plasma and brain tissues. Only 40 µL of plasma is needed for analysis due to the high sensitivity of this method, which could be completed in less than three minutes. This method was used to study the pharmacokinetics of EZ in SD rats, and the transport of EZ in Caco-2 and MDCK-MDR1 overexpressing cell culture models. Our data show that EZ is not a substrate for p-glycoprotein (P-gp) and its entry into the brain may not limited by the blood-brain barrier. PMID:25706567

  14. Simultaneous determination of five components in rat plasma by UPLC-MS/MS and its application to a comparative pharmacokinetic study in Baihe Zhimu Tang and Zhimu extract.

    PubMed

    Li, Guolong; Tang, Zhishu; Yang, Jie; Duan, Jinao; Qian, Dawei; Guo, Jianming; Zhu, Zhenhua; Liu, Hongbo

    2015-01-01

    Baihe Zhimu Tang (BZT) is a famous traditional Chinese medicine recipe to treat dry coughing due to yin deficiency and for moisturizing the lungs. Zhimu is an essential ingredient in BZT used to treat inflammation, fever and diabetes. The most important active components in Zhimu are flavonoids such as neomangiferin, mangiferin, and steroid saponins (e.g., timosaponin BII, anemarsaponin BIII, timosaponin AIII). The aim of this study was to compare the pharmacokinetics of mangiferin, neomangiferin, timosaponin BII, anemarsaponin BIII and timosaponin AIII in rat plasma after oral administration of BZT and Zhimu extract (ZME). A sensitive, reliable and robust LC-MS/MS method to simultaneously determine steroid saponins and flavonoids in rat plasma was successfully validated. Significant differences (p < 0.05) were found in the pharmacokinetic parameters of timosaponin BII, anemarsaponin BIII and timosaponin AIII between BZT and ZME. It was surmised that formula compatibility could significantly influence the pharmacokinetics of BZT and our study is the first to study the administration of BZT based on pharmacokinetic studies.

  15. Simultaneous determination of five components in rat plasma by UPLC-MS/MS and its application to a comparative pharmacokinetic study in Baihe Zhimu Tang and Zhimu extract.

    PubMed

    Li, Guolong; Tang, Zhishu; Yang, Jie; Duan, Jinao; Qian, Dawei; Guo, Jianming; Zhu, Zhenhua; Liu, Hongbo

    2015-01-01

    Baihe Zhimu Tang (BZT) is a famous traditional Chinese medicine recipe to treat dry coughing due to yin deficiency and for moisturizing the lungs. Zhimu is an essential ingredient in BZT used to treat inflammation, fever and diabetes. The most important active components in Zhimu are flavonoids such as neomangiferin, mangiferin, and steroid saponins (e.g., timosaponin BII, anemarsaponin BIII, timosaponin AIII). The aim of this study was to compare the pharmacokinetics of mangiferin, neomangiferin, timosaponin BII, anemarsaponin BIII and timosaponin AIII in rat plasma after oral administration of BZT and Zhimu extract (ZME). A sensitive, reliable and robust LC-MS/MS method to simultaneously determine steroid saponins and flavonoids in rat plasma was successfully validated. Significant differences (p < 0.05) were found in the pharmacokinetic parameters of timosaponin BII, anemarsaponin BIII and timosaponin AIII between BZT and ZME. It was surmised that formula compatibility could significantly influence the pharmacokinetics of BZT and our study is the first to study the administration of BZT based on pharmacokinetic studies. PMID:25884551

  16. Theoretical Study of a Spherical Plasma Focus

    NASA Astrophysics Data System (ADS)

    Ay, Yasar

    A theoretical model is developed for two concentric electrodes spherical plasma focus device in order to investigate the plasma sheath dynamics, radiative emission, and the ion properties. The work focuses on the model development of the plasma sheath dynamics and its validation, followed by studying of the radiation effects and the beam-ion properties in such unique geometry as a pulsed source for neutrons, soft and hard x-rays, and electron and ion beams. Chapter 1 is an introduction on fusion systems including plasma focus. Chapter 2 is an extensive literature survey on plasma focus modeling and experiments including the various radiations and their mechanism. Chapter 3 details modeling and validation of the plasma sheath dynamics model with comparison between hydrogen, deuterium, tritium and deuterium-tritium mixture for the production of pulsed neutrons. Chapter 4 is a study of the radiative phase, in which neutron yield is investigated, as well as the predicted beam-ion properties. Chapter 5 summarizes and discusses the results. Chapter 6 provides concluding remarks and proposed future works. The phases of the developed model are the rundown phase I, rundown phase II, the reflected phase and a radiative phase. The rundown phase I starts immediately after the completion of the gas breakdown and ends when the current sheath reaches the equator point of the spherical shape. Then immediately followed by rundown phase II to start and it ends when the shock front hits the axis, which is the beginning of the reflected shock phase. Reflected shock front moves towards the incoming current sheath and meets it which is both the end of the reflected shock phase and the beginning of the radiative phase. After the reflected shock front and the current sheath meet, the current sheath continues to move radially inward by compressing the produced plasma column until it reaches the axis. Since the discharge current contains important information about the plasma dynamic

  17. Experimental studies of collisional plasma shocks and plasma interpenetration via merging supersonic plasma jets

    NASA Astrophysics Data System (ADS)

    Hsu, S. C.; Moser, A. L.; Merritt, E. C.; Adams, C. S.

    2015-11-01

    Over the past 4 years on the Plasma Liner Experiment (PLX) at LANL, we have studied obliquely and head-on-merging supersonic plasma jets of an argon/impurity or hydrogen/impurity mixture. The jets are formed/launched by pulsed-power-driven railguns. In successive experimental campaigns, we characterized the (a) evolution of plasma parameters of a single plasma jet as it propagated up to ~ 1 m away from the railgun nozzle, (b) density profiles and 2D morphology of the stagnation layer and oblique shocks that formed between obliquely merging jets, and (c) collisionless interpenetration transitioning to collisional stagnation between head-on-merging jets. Key plasma diagnostics included a fast-framing CCD camera, an 8-chord visible interferometer, a survey spectrometer, and a photodiode array. This talk summarizes the primary results mentioned above, and highlights analyses of inferred post-shock temperatures based on observations of density gradients that we attribute to shock-layer thickness. We also briefly describe more recent PLX experiments on Rayleigh-Taylor-instability evolution with magnetic and viscous effects, and potential future collisionless shock experiments enabled by low-impurity, higher-velocity plasma jets formed by contoured-gap coaxial guns. Supported by DOE Fusion Energy Sciences and LANL LDRD.

  18. Highly sensitive LC-MS/MS-ESI method for determination of phenelzine in human plasma and its application to a human pharmacokinetic study.

    PubMed

    Kallem, Raja Reddy; Jillela, Bhupathi; Ravula, Arun Reddy; Samala, Ramakrishna; Andy, Adinarayana; Ramesh, Mullangi; Rao, Jvln Seshagiri

    2016-06-01

    A selective, sensitive and rapid LC-MS/MS method has been developed and validated for quantification of the phenelzine (PZ) in 200μL of human plasma using hydroxyzine (HZ) as an internal standard (IS) as per regulatory guidelines. The sample preparation involved the derivatization of PZ using pentaflurobenzaldehyde followed by solid phase extraction process to extract PZ and HZ from human plasma. LC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using the electro spray ionization technique in positive ion mode and the transitions of m/z 305.1→105.1 and m/z 375.3→201.1 were used to measure the derivative of PZ and IS, respectively. The total run time was 3.5min and the elution of PZ and HZ occurred at 2.53, and 1.92min, respectively; this was achieved with a mobile phase consisting of 10mM ammonium acetate: acetonitrile (20:80, v/v) at a flow rate of 1.0mL/min on an Ace C18 column with a split ratio of 70:30. The developed method was validated in human plasma with a lower limit of quantitation 0.51ng/mL. A linear response function was established for the range of concentrations 0.51-25.2ng/mL (r>0.995) for PZ. The intra- and inter-day precision values met the acceptance criteria. PZ was stable in the battery of stability studies viz., stock solution, bench-top, auto-sampler, long-term and freeze/thaw cycles. The developed assay method was applied to an oral bioequivalence study in humans. PMID:27085800

  19. Reverse-phase liquid chromatography with electrospray ionization/mass spectrometry for the quantification of pseudoephedrine in human plasma and application to a bioequivalence study.

    PubMed

    Kim, Jin-Ki; Jee, Jun-Pil; Park, Jeong-Sook; Kim, Hyung Tae; Kim, Chong-Kook

    2011-01-01

    A sensitive and selective reverse-phase liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS) method was developed and validated to quantify pseudoephedrine (CAS 90-82-4) in human plasma. Phenacetin was used as the internal standard (I.S.). Sample preparation was performed with a deproteinization step using acetonitrile. Pseudoephedrine and I.S. were successfully separated using gradient elution with 0.5% trifluoroacetic acid (TFA) in water and 0.5% TFA in methanol at a flow-rate of 0.2 mL/min. Detection was performed on a single quadrupole mass spectrometer by a selected ion monitoring (SIM) mode via electrospray ionization (ESI) source. The ESI source was set at positive ionization mode. The ion signals of m/z 166.3 and 180.2 were measured for the protonated molecular ions of pseudoephedrine and I.S., respectively. The lower limit of quantification (LLOQ) of pseudoephedrine in human plasma was 10 ng/mL and good linearity was observed in the range of concentrations 10-500 ng/mL (R2 = 1). The intra-day accuracy of the drug containing plasma samples was more than 97.60% with a precision of 3.99-11.82%. The inter-day accuracy was 99.36% or more, with a precision of 7.65-18.42%. By using this analytical method, the bioequivalence study of the pseudoephedrine preparation was performed and evaluated by statistical analysis of the log transformed mean ratios of pharmacokinetic parameters. All the results fulfilled the standard criteria of bioequivalence, being within the 80-125% range which is required by the Korea FDA, US FDA, and EMEA to conclude bioequivalence. Consequently, the developed reverse-phase LC-ESI-MS method was successfully applied to bioequivalence studies of pseudoephedrine in healthy male volunteers.

  20. Plasma Functionalized Nanocarbon Materials and Their Applications

    NASA Astrophysics Data System (ADS)

    Li, Yongfeng

    2015-09-01

    The plasma treatment method is important for modifying carbon nanomaterials since it has the advantage of being nonpolluting. It has the possibility of scaling up to produce large quantities necessary for commercial use. The liquid-related plasma is especially advantageous in avoiding use of toxic stabilizers and reducing agents during the nanoparticle formation process. In this work, both gas phase and liquid phase plasmas are used to modify nanocarbon materials including graphene and carbon nanotubes. The synthesis of metal nanoparticles functionalized nanocarbon materials including carbon nanotubes and graphene has been realized by an environmentally-friendly gas-liquid interfacial method. Furthermore, the new catalysts based on hybrid of nanocarbon materials and metal nanoparticles have been proved to be stable and high catalytic performance in organic molecule transformation reactions. In addition, the modification of few-layer graphene grown by chemical vapour deposition via the nitrogen plasma ion irradiation has been performed, and the modified graphene sheets as counter electrodes in bifacial dye-sensitized solar cells exhibit high performance.

  1. Plasma-etched nanostructures for optical applications (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Schulz, Ulrike; Rickelt, Friedrich; Munzert, Peter; Kaiser, Norbert

    2015-08-01

    A basic requirement for many optical applications is the reduction of Fresnel-reflections. Besides of interference coatings, nanostructures with sub-wavelength size as known from the eye of the night-flying moth can provide antireflective (AR) properties. The basic principle is to mix a material with air on a sub-wavelength scale to decrease the effective refractive index. To realize AR nanostructures on polymers, the self-organized formation of stochastically arranged antireflective structures using a low-pressure plasma etching process was studied. An advanced procedure involves the use of additional deposition of a thin oxide layer prior etching. A broad range of different structure morphologies exhibiting antireflective properties can be generated on almost all types of polymeric materials. For applications on glass, organic films are used as a transfer medium. Organic layers as thin film materials were evaluated to identify compounds suitable for forming nanostructures by plasma etching. The vapor deposition and etching of organic layers on glass offers a new possibility to achieve antireflective properties in a broad spectral range and for a wide range of light incidence.

  2. Novel applications of atmospheric pressure plasma on textile materials

    NASA Astrophysics Data System (ADS)

    Cornelius, Carrie Elizabeth

    Various applications of atmospheric pressure plasma are investigated in conjunction with polymeric materials including paper, polypropylene non-woven fabric, and cotton. The effect of plasma on bulk and surface properties is examined by treating both cellulosic pulp and prefabricated paper with various plasma-gas compositions. After treatment, pulp is processed into paper and the properties are compared. The method of pulp preparation is found to be more significant than the plasma, but differences in density, strength, and surface roughness are apparent for the pulp vs. paper plasma treatments. The plasma is also used to remove sizes of PVA and starch from poly/cotton and cotton fabric respectively. In both cases plasma successfully removes a significant amount of size, but complete size removal is not achieved. Subsequent washes (PVA) or scouring (cotton) to remove the size are less successful than a control, suggesting the plasma is crosslinking the size that is not etched away. However, at short durations in cold water using an oxygen plasma, slightly more PVA is removed than with a control. For the starch sized samples, plasma and scouring are never as successful at removing starch as a conventional enzyme, but plasma improves dyeability without need for scouring. Plasma is also used to graft chemicals to the surface of polypropylene and cotton fabric. HTCC, an antimicrobial is grafted to polypropylene with successful grafting indicated by x-ray photoemission spectroscopy (XPS), dye tests, and Fourier transform infrared spectroscopy (FTIR). Antimicrobial activity of the grafted samples is also characterized. 3ATAC, a vinyl monomer is also grafted to polypropylene and to cotton. Additives including Mohr's salt, potassium persulfate, and diacrylate are assessed to increase yield. Successful grafting of 3ATAC is confirmed by XPS and dye testing. A combination of all three additives is identified as optimum for maximizing graft yield.

  3. LC-MS/MS assay for the determination of lurasidone and its active metabolite, ID-14283 in human plasma and its application to a clinical pharmacokinetic study.

    PubMed

    Katteboina, Mahitej Yadav; Pilli, Nageswara Rao; Mullangi, Ramesh; Seelam, Raghunadha Reddy; Satla, Shobha Rani

    2016-07-01

    The authors proposed a sensitive, selective and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay procedure for the quantification of lurasidone and its active metabolite, i.e. ID-14283 in human plasma simultaneously using corresponding isotope labeled compounds as internal standards as per regulatory guidelines. After liquid-liquid extraction with tert-butyl methyl ether, the analytes were chromatographed on a C18 column using an optimized mobile phase composed of 5 mm ammonium acetate (pH 5.0) and acetonitrile (15:85, v/v) and delivered at a flow rate of 1.00 mL/min. The assay exhibits excellent linearity in the concentration ranges of 0.25-100 and 0.10-14.1 ng/mL for lurasidone and ID-14283, respectively. The precision and accuracy results over five concentration levels in four different batches were well within the acceptance limits. Lurasidone and ID-14283 were found to be stable in battery of stability studies. The method was rapid with the chromatographic run time 2.5 min, which made it possible to analyze 300 samples in a single day. Additionally, this method was successfully used to estimate the in vivo plasma concentrations of lurasidone and ID-14283 obtained from a pharmacokinetic study in south Indian male subjects and the results were authenticated by conducting incurred samples reanalysis. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26577488

  4. Development and validation of a highly sensitive LC-MS/MS method for quantitation of bivalirudin in human plasma: application to a human pharmacokinetic study.

    PubMed

    Chai, Dong; Wang, Rui; Bai, Nan; Cai, Yun; Liang, Beibei

    2013-12-01

    A sensitive, specific and simple LC-MS/MS method was developed for the identification and quantification of bivalirudin in human plasma using diazepam as an internal standard (IS). The API-4000 LC-MS/MS was operated under multiple-reaction monitoring mode using electrospray ionization. The sample preparation consisted of an easy protein precipitation sample pretreatment with methanol. Chromatographic separation was achieved on a Zorbax Eclipse plus C18 100 × 2.1 mm column with a mobile phase of water-methanol-0.1% formic acid. The analytes were detected with a triple quadrupole Quantum Access with positive ionization. Ions monitored in the multiple-reaction monitoring mode were m/z 1091 → 650 for bivalirudin (at 2.70 min) and m/z 285 → 193 for diazepam (at 3.85 min). The developed method was validated in human plasma with a lower limit of quantitation of 20 µg/L for bivalirudin. A linear response function was established for the range of concentrations 20-10,000 µg/L (r > 0.998) for bivalirudin. The intra- and inter-day precision values for bivalirudin met the acceptance criteria as per US Food and Drug Administration guidelines. Bivalirudin was stable in the battery of stability studies, viz. bench-top, freeze-thaw cycles and long-term stability. The developed assay method was applied to an intravenous administration study in humans. PMID:23893840

  5. Determination of tulobuterol in rat plasma using a liquid chromatography-tandem mass spectrometry method and its application to a pharmacokinetic study of tulobuterol patch.

    PubMed

    Han, Xiao; Liu, Ran; Ji, Lifang; Hui, Mei; Li, Qing; Fang, Liang; Bi, Kaishun

    2016-01-01

    A sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for determination of tulobuterol in rat plasma for the first time. Plasma samples were extracted by liquid-liquid extraction method with methyl tert-butyl ether and the analyte and clenbuterol (IS) were separated on a Venusil MP C18 column (100mm×2.1mm, 3μm) using 0.1% formic acid-water-methanol as mobile phase, with a runtime of 5min. The analyte was detected in multiple reaction monitoring (MRM) mode with positive electrospray ionization. Transitions of m/z 228.2→154.0 for tulobuterol and m/z 277.1→203.0 for the clenbuterol were monitored. The linear range was 0.5-100ng/ml (r=0.9967) for tulobuterol with the lower limit of quantitation of 0.5ng/ml. The intra-day and inter-day precisions were less than 10.3% for the analyte and the accuracy was less than -8.6%. The RSD of matrix effect and recovery yield were within ±15% of nominal concentrations and tulobuterol was stable during stability studies. The validated method has been successfully applied to a pharmacokinetic study of three doses of tulobuterol patch in rats for the first time. PMID:26638035

  6. Determination of tulobuterol in rat plasma using a liquid chromatography-tandem mass spectrometry method and its application to a pharmacokinetic study of tulobuterol patch.

    PubMed

    Han, Xiao; Liu, Ran; Ji, Lifang; Hui, Mei; Li, Qing; Fang, Liang; Bi, Kaishun

    2016-01-01

    A sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for determination of tulobuterol in rat plasma for the first time. Plasma samples were extracted by liquid-liquid extraction method with methyl tert-butyl ether and the analyte and clenbuterol (IS) were separated on a Venusil MP C18 column (100mm×2.1mm, 3μm) using 0.1% formic acid-water-methanol as mobile phase, with a runtime of 5min. The analyte was detected in multiple reaction monitoring (MRM) mode with positive electrospray ionization. Transitions of m/z 228.2→154.0 for tulobuterol and m/z 277.1→203.0 for the clenbuterol were monitored. The linear range was 0.5-100ng/ml (r=0.9967) for tulobuterol with the lower limit of quantitation of 0.5ng/ml. The intra-day and inter-day precisions were less than 10.3% for the analyte and the accuracy was less than -8.6%. The RSD of matrix effect and recovery yield were within ±15% of nominal concentrations and tulobuterol was stable during stability studies. The validated method has been successfully applied to a pharmacokinetic study of three doses of tulobuterol patch in rats for the first time.

  7. Simultaneous determination of lercanidipine, benazepril and benazeprilat in plasma by LC-MS/MS and its application to a toxicokinetics study.

    PubMed

    Chen, Keguang; Zhang, Jing; Liu, Sha; Zhang, Dujuan; Teng, Yanni; Wei, Chunmin; Wang, Benjie; Liu, Xiaoyan; Yuan, Guiyan; Zhang, Rui; Zhao, Wenjing; Guo, Ruichen

    2012-06-15

    We aim to develop a rapid, simple, sensitive and specific LC-MS/MS method for the simultaneous quantification of lercanidipine, benazepril and benazeprilat in plasma. It is performed on the Agilent 6410 LC-MS/MS under the multiple-reaction monitoring (MRM) mode with electrospray ionization. Gliclazide was used as the internal standard (IS). Analytes and IS were extracted from plasma by solid-phase extraction. The reconstituted samples were chromatographed on a Diamond C₁₈(150 mm × 4.6 mm, 5 μm) column. The mobile phase was composed of 0.1% acetic acid-acetonitrile (50:50, v/v), with gradient flow rates: 0.6 mL/min (0-4.55 min); 4.55-4.65 min, 1 mL/min; 1 mL/min (4.65-9.5 min); 9.5-9.6 min, 0.6 mL/min; 0.6 mL/min (9.6-10 min). Method validation demonstrated that the method was of satisfactory specificity, sensitivity, precision and accuracy in linear ranges of 1-2000 ng/mL for lercanidipine, 1-2000 ng/mL for benazepril and 1-1600 ng/mL for benazeprilat, respectively. The precision (RSD%) was better than 15, and the lower limit of quantitation was identifiable and reproducible at 1 ng/mL for the three analytes. The plasma samples were stable after being stored for more than 60 days and after two freeze-thaw cycles (-20 to -25 °C). It is demonstrated that this method was successfully applied to samples from a toxicokinetics study of a compound of lercanidipine and benazepril in beagle dogs. PMID:22622066

  8. Simultaneous determination of four furostanol glycosides in rat plasma by UPLC-MS/MS and its application to PK study after oral administration of Dioscorea nipponica extracts.

    PubMed

    Liao, Min; Dai, Cong; Liu, Mengping; Chen, Jiefeng; Chen, Zuanguang; Xie, Zhiyong; Yao, Meicun

    2016-01-01

    A novel, sensitive and rapid ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method for simultaneous quantification of four furostanol glycosides in rat plasma was established and validated. Ginsenoside Rb1 was used as an internal standard. Plasma samples were pretreated by liquid-liquid extraction with n-butanol and chromatographed on a C18 column (2.1×50 mm i.d., 2.6 μm) using a gradient elution program consisting of acetonitrile and water (containing 0.03% formic acid and 0.1 mM lithium acetate) at a flow rate of 0.4 mL/min. Lithium adduct ions were employed to enhance the response of the analytes in electrospray positive ionization mode and multiple reaction monitoring transitions were performed for detection. All calibration curves exhibited good linearity (r>0.999) over the range of 10-20,000 ng/mL for protodioscin and 2-4000 ng/mL for protogracillin, pseudoprotodioscin and pseudoprotogracillin. The recoveries of the whole analytes were more than 80.3% and exhibited no severe matrix effect. Meanwhile, the intra- and inter-day precisions were all less than 10.7% and accuracies were within the range of -8.1-12.9%. The four saponins showed rapid excretion and relative high plasma concentrations when the validated method was applied to the PK study of Dioscorea nipponica extracts by intragastric administration at low, medium and high dose to rats. Moreover, the T(1/2) and AUC(0-t) of each compound turned out to behave in a dose-dependent pattern by comparing them at different dose levels.

  9. Simultaneous determination of probe drugs, metabolites, inhibitors and inducer in human plasma by liquid chromatography/tandem mass spectrometry and its application to pharmacokinetic study.

    PubMed

    Hee, Kim H; Yao, Zhangyan; Lee, Lawrence S

    2014-01-01

    Cytochrome P450 3A4 (CYP3A4) and UDP-glucuronosyltransferase 1A1 (UGT1A1) are important enzymes responsible for the metabolism of many xenobiotics. To investigate their induction and inhibition properties, administering probe drugs and monitoring their concentration in plasma under the effects of inducers/inhibitors is the gold standard method. A rapid and sensitive liquid chromatography-tandem mass spectrometry method was developed for simultaneous quantification of midazolam, raltegravir (probe drugs for CYP3A4 and UGT1A1), their major metabolites, 1'-hydroxymidazolam, 1'-hydroxymidazolam glucuronide and raltegravir glucuronide, rifampicin (inducer), ritonavir and ketoconazole (inhibitors). Analytes were extracted from 100μl of plasma using solid-phase extraction followed by chromatographic separation on a reversed-phase C18 column (50mm×2.1mm, particle size 1.8μm). The mass spectrometer was operated under positive ionization mode. Excellent linearity (r(2)≥0.995) was achieved for all. The method was validated and found to be accurate (88-111%), precise (CV%<13) and selective. Matrix effect was acceptable (88-118%) and analytes recovery was reproducible (60-95%). Analytes in plasma were also found to be stable in the autosampler (6°C for 48h) and after two freeze-thaw cycles. We have developed a robust analytical method to simultaneously quantify probes, inducer and inhibitor of important drug metabolism enzymes. The method was successfully applied in a clinical study to investigate the degree of induction and inhibition of CYP3A4 and UGT1A1 among ethnic groups in Singapore. PMID:24211708

  10. A selective and sensitive method based on UPLC-MS/MS for quantification of momordin Ic in rat plasma: application to a pharmacokinetic study.

    PubMed

    Yan, Huiyu; Song, Yanqing; Zhou, Wei; Zhang, Sixi

    2015-11-10

    A selective and sensitive method was developed and validated based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). This method was applied to quantify momordin Ic in rat plasma. Chromatographic separation was performed on a Hypersil GOLD HPLC C18 column (150mm×4.6mm, 5μm) using an isocratic mobile phase of acetonitrile/water (80:20, v/v) at a flow rate of 0.6mL/min. An electrospray ionization source was applied and operated in negative ion mode; selected reaction monitoring (SRM) mode was used for quantification by monitoring the precursor-to-product ion transitions of m/z 763.4→m/z 455.3 for momordin Ic, and m/z 649.4→m/z 487.3 for IS. Calibration curves showed good linearity over the range of 22.0-2200ng/mL for momordin Ic in rat plasma. The developed method was applied to a pharmacokinetic study of momordin Ic in rats after single intravenous doses at 0.52, 1.56, and 4.67mg/kg. The elimination half-life (t1/2) values were 1.22±0.39, 1.14±0.10, and 1.83±0.39h, respectively. The plasma concentration at 2min (C2min) and area under the curve (AUC) for the intravenous doses of momordin Ic were approximately dose proportional. PMID:26218506

  11. Determination of a highly selective mixed-affinity sigma receptor ligand, in rat plasma by ultra performance liquid chromatography mass spectrometry and its application to a pharmacokinetic study

    PubMed Central

    Jamalapuram, Seshulatha; Vuppala, Pradeep K.; Mesangeau, Christophe; McCurdy, Christopher R.; Avery, Bonnie A.

    2014-01-01

    A selective, rapid and sensitive ultra performance liquid chromatography mass spectrometry (UPLC/MS) method was developed and validated to quantitate a highly selective mixed-affinity sigma receptor ligand, CM156 (3-(4-(4-cyclohexylpiperazin-1-yl)butyl)benzo[d] thiazole-2(3H)-thione), in rat plasma. CM156 and the internal standard (aripiprazole) were extracted from plasma samples by a single step liquid–liquid extraction using chloroform. The analysis was carried out on an ACQUITY UPLCTM BEH HILIC column (1.7 µm, 2.1 mm × 50 mm) with isocratic elution at flow rate of 0.2 mL/min using 10 mM ammonium formate in 0.1% formic acid and acetonitrile (10:90) as the mobile phase. The detection of the analyte was performed on a mass spectrometer operated in selected ion recording (SIR) mode with positive electrospray ionization (ESI). The validated analytical method resulted in a run time of 4 min and the retention times observed were 2.6 ± 0.1 and 2.1 ± 0.1 min for CM156 and the IS, respectively. The calibration curve exhibited excellent linearity over a concentration range of 5–4000 ng/mL with the lower limit of quantification of 5 ng/mL. The intra- and inter-day precision values were below 15% and accuracy ranged from −6.5% to 5.0%. The mean recovery of CM156 from plasma was 96.8%. The validated method was applied to a pilot intravenous pharmacokinetic study in rats. PMID:22406103

  12. UPLC-MS-MS method for simultaneous determination of caffeine, tolbutamide, metoprolol, and dapsone in rat plasma and its application to cytochrome P450 activity study in rats.

    PubMed

    Liu, Yan; Li, Xiang; Yang, Chunjuan; Tai, Sheng; Zhang, Xiangning; Liu, Gaofeng

    2013-01-01

    A specific ultra-performance liquid chromatography tandem mass spectrometry method has been described for the simultaneous determination of caffeine, tolbutamide, metoprolol and dapsone in rat plasma, which are the four probe drugs of the four cytochrome P450 (CYP450) isoforms CYP1A2, CYP2C9, CYP2D6 and CYP3A4. The chromatographic separation was achieved using a Waters Acquity UPLC BEH HILIC C(18) column (2.1 × 50 mm, 1.7 µm). The mobile phase consisted of acetonitrile and water (containing 0.1% formic acid) (15:85, v/v). The triple quadrupole mass spectrometric detection was operated by positive electrospray ionization. Phenacetin was chosen as internal standard. Plasma samples were extracted with dichloromethane-butanol (10:1, v/v). The recoveries ranged from 67.5% to 98.5%. The calibration curves in plasma were linear in the range of 2.5-1,000 ng/mL for caffeine and dapsone, 5-5,000 ng/mL for tolbutamide and 2.5-250 ng/mLfor metoprolol, with correlation coefficient (r(2)) of 0.9936, 0.9966, 0.9990 and 0.9998, respectively. The method was successfully applied to pharmacokinetic studies of the four probe drugs of the four CYP450 isoforms and used to evaluate the effects of breviscapine on the activities of CYP1A2, CYP2C9, CYP2D6 and CYP3A4 in rats.

  13. Plasma Liner Development for MTF Applications: A Status Report

    NASA Technical Reports Server (NTRS)

    Eskridge, R. E.; Thio, Y. F.; Lee, M.; Martin, A.; Smith, J. W.; Griffin, S. T.; Schafer, Charles (Technical Monitor)

    2001-01-01

    An experimental plasma gun for Magnetic Target Fusion (MTF) applications under development at the NASA Marshall Space Flight Center is described. This gun has been tested experimentally and plasma jet velocities of approximately 50 km/sec have been obtained. The plasma jet structure has been photographed with 10 ns exposure times to reveal a stable and repeatable plasma structure. Data for velocity profile information has been obtained using light pipes embedded in the gun walls to record the plasma transit at various barrel locations. A high speed triggering system has been developed and tested as a means of reducing the gun "jitter". This jitter has been characterized and future work for second generation "ultra-low jitter" gun development is identified.

  14. Fabrication of Plasma Transient Density Structures and its Application to High-Field Plasma Devices

    SciTech Connect

    Chen Szuyuan; Wang Jyhpyng; Lin Jiunnyuan

    2006-11-27

    Fabrications of plasma transient density structures such as plasma waveguide, variable gas jet length, longitudinal density structure, and transverse wiggler by using laser machining in a gas jet are presented. The implementations of the technique of variable gas jet length with laser machining to achieve tomographic diagnosis of laser wakefield electron acceleration, x-ray lasing, and high harmonic generation are reported. Applications of these elements of high-field plasma devices and their combinations to enhance the products in high-field physics are presented or proposed.

  15. Industrial applications of low-temperature plasma physics

    SciTech Connect

    Chen, F.F.

    1995-06-01

    The application of plasma physics to the manufacturing and processing of materials may be the new frontier of our discipline. Already partially ionized discharges are used in industry, and the performance of plasmas has a large commercial and technological impact. However, the science of low-temperature plasmas is not as well developed as that of high-temperature, collisionless plasmas. In this paper several major areas of application are described and examples of forefront problems in each are given. The underlying thesis is that gas discharges have evolved beyond a black art, and that intellectually challenging problems with elegant solutions can be found. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  16. Computational study of nonlinear plasma waves. [plasma simulation model applied to electrostatic waves in collisionless plasma

    NASA Technical Reports Server (NTRS)

    Matsuda, Y.

    1974-01-01

    A low-noise plasma simulation model is developed and applied to a series of linear and nonlinear problems associated with electrostatic wave propagation in a one-dimensional, collisionless, Maxwellian plasma, in the absence of magnetic field. It is demonstrated that use of the hybrid simulation model allows economical studies to be carried out in both the linear and nonlinear regimes with better quantitative results, for comparable computing time, than can be obtained by conventional particle simulation models, or direct solution of the Vlasov equation. The characteristics of the hybrid simulation model itself are first investigated, and it is shown to be capable of verifying the theoretical linear dispersion relation at wave energy levels as low as .000001 of the plasma thermal energy. Having established the validity of the hybrid simulation model, it is then used to study the nonlinear dynamics of monochromatic wave, sideband instability due to trapped particles, and satellite growth.

  17. Plasma display technology for scene projector application

    NASA Astrophysics Data System (ADS)

    Solomon, Steve; Hawkins, Mikhel; Mastronardi, Nick

    2005-05-01

    Plasma display technology was investigated to determine its suitability for scene projection, particularly in the ultraviolet portion of the electromagnetic spectrum. This technology, in several guises, was found to hold considerable promise for projecting very high radiance, broadband or narrowband scenes across the spectrum, from the ultraviolet to the infrared. Performance metrics such as temporal response and dynamic range were also found to be promising for this technology. High manufacturing yields at relatively low display cost (e.g. cost/pixel) are expected due to the simplicity of the devices, the ability to leverage modern microelectronics-based deposition, pattern and etching techniques as well as the commercial plasma display community that continues to improve performance and drive manufacturing costs down.

  18. Radio Frequency Plasma Applications for Space Propulsion

    SciTech Connect

    Baity, F.W., Jr.; Barber, G.C.; Carter, M.D.; Chang-Diaz, F.R.; Goulding, R.H.; Ilin, A.V.; Jaeger, E.F.; Sparks, D.O.; Squire, J.P.

    1999-09-13

    Recent developments in solid-state radio frequency (RF) power technologies allow for the practical consideration of RF heated plasmas for space propulsion. These technologies permit the use of any electrical power source, de-couple the power and propellant sources, and allow for the effcient use of both the propellant mass and power. Effcient use of the propellant is obtained by expelling the rocket exhaust at the highest possible velocity, which can be orders of magnitude higher than those achieved in chemical rockets. Handling the hot plasma exhaust requires the use of magnetic nozzles, and the basic physics of ion detachment from the magnetic eld is discussed. The plasma can be generated by RF using helicon waves to heat electrons. Further direct heating of the ions helps to reduce the line radiation losses, and the magnetic geometry is tailored to allow ion cyclotron resonance heating. RF eld and ion trajectory calculations are presented to give a reasonably self-consistent picture of the ion acceleration process.

  19. HPLC determination of five polyphenols in rat plasma after intravenous administration of hawthorn leaves extract and its application to pharmacokinetic study.

    PubMed

    Wang, Si-Yuan; Chai, Ji-Yan; Zhang, Wen-Jie; Liu, Xun; DU, Yang; Cheng, Zhong-Zhe; Ying, Xi-Xiang; Kang, Ting-Guo

    2010-11-01

    A simple and specific HPLC-UV method was developed to simultaneously determine five active compounds including vitexin-4"-O-glucoside (VG), vitexin-2"-O-rhamnoside (VR), vitexin (VIT), rutin (RUT) and hyperoside (HP) in rat plasma after intravenous administrating the hawthorn leaves extract (HLE). With baicalin as internal standard (I.S.), sample pretreatment involved a one-step extraction with methanol of 0.2 ml plasma. The HPLC assay was carried out using a Phenomsil C18 analytical column with UV detection at 332 nm. The mobile phase consisted of methanol-acetonitrile-tetrahydrofuran-1% glacial acetic acid (6:1.5:18.5:74, v/v/v/v). The calibration curves were liner over the range of 2.030-500.5, 0.1513-75.64, 0.2507-12.54, 0.5128-25.64 and 0.4032-20.16 µg/ml for VG, VR, VIT, RUT and HP, respectively. The relative standard deviations (RSD) of the intra- and inter-day precisions for the analysis of the five analytes were between 1.0 and 8.9% with accuracies (relative error) below 8.2% for the analysis of the five analytes. The average extraction recoveries of five analytes were more than 82.67 ± 4.74%. The HPLC method herein described was fully validated and successfully applied to the pharmacokinetic studies after intravenous administration of HLE solution to rats over three doses.

  20. A rapid and sensitive LC-MS/MS method for determination of lercanidipine in human plasma and its application in a bioequivalence study in Chinese healthy volunteers.

    PubMed

    Li, Xiaobing; Shi, Fuguo; He, Xiaojing; Jian, Lingyan; Ding, Li

    2016-09-01

    A rapid and highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the determination of lercanidipine (LER) in human plasma. The plasma sample was deproteinized with methanol after addition of diazepam (internal standard, IS) and separated on a 38°C Hedera ODS-2 analytical column with a mobile phase of methanol and 5mM ammonium acetate buffer solution containing 0.1% formic acid at an isocratic flow rate of 400μL/min. The detection was performed on an API 4000 tandem mass spectrometer coupled with electrospray ionization (ESI) source in positive ESI mode. Quantification was conducted by multiple reaction monitoring (MRM) of the transitions of m/z 612.2→280.2 for LER and m/z 285.1→193.1 for IS, respectively. The method exhibited high sensitivity (LLOQ of 0.015ng/mL) and good linearity over the concentration range of 0.015-8.0ng/mL. No matrix effect and carry-over effect were observed. The values on both the occasions (intra- and inter-day) were all within 15% at three concentration levels. This robust method was successfully applied in a bioequivalence study to evaluate the pharmacokinetics of LER in 59 healthy male Chinese volunteers after a single oral administration of 10mg LER. PMID:27232153

  1. Liquid chromatograph/tandem mass spectrometry assay for the simultaneous determination of chlorogenic acid and cinnamic acid in plasma and its application to a pharmacokinetic study.

    PubMed

    Zhang, Jun; Chen, Min; Ju, Wenzheng; Liu, Shijia; Xu, Meijuan; Chu, Jihong; Wu, Ting

    2010-02-01

    A rapid and high sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for simultaneous determination of chlorogenic acid and cinnamic acid in human plasma was developed. The analytes and internal standard (IS), tinidazole, were extracted from human plasma via liquid/liquid extraction with ether-ethyl acetate (1:1, v/v) and separated on an Agilent Zorbax SB C18 column within 5min. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring (MRM) and negative ion mode. The precursor to product ion transitions monitored for chlorogenic acid, cinnamic acid and IS were m/z 352.9-->191.1, 146.8-->103.1, 245.6-->126.0, respectively. The assay was validated with linear range of 1.00-800.00ng/mL for chlorogenic acid and 0.50-400.00ng/mL for cinnamic acid. The intra- and inter-day precisions (RSD%) were within 9.05% for each analyte. The absolution recoveries were greater than 74.62% for chlorogenic acid and 76.21% for cinnamic acid. Each analyte was proved to be stable during all sample storage, preparation and analytic procedures. The method was successfully applied to a pharmacokinetic study of Mailuoning injection in 10 healthy volunteers.

  2. Simultaneous quantification of two canthinone alkaloids of Picrasma quassioides in rat plasma by liquid chromatography-tandem mass spectrometry and its application to a rat pharmacokinetic study.

    PubMed

    Shi, Yuanyuan; Hong, Chunyan; Xu, Jian; Yang, Xiaoling; Xie, Ning; Feng, Feng; Liu, Wenyuan

    2015-04-01

    Picrasma quassioides (D. Don) Benn. is used in traditional Chinese medicine for the treatment of inflammation. Characteristic components of the medicinal extract are canthinone alkaloids. In this study, a sensitive and rapid liquid chromatography with tandem mass spectrometry method has been developed for simultaneous quantification of two major canthinone alkaloids, 5-hydroxy-4-methoxycanthin-6-one and 4,5-dimethoxycanthin-6-one, in rat plasma after oral administration of P. quassioides extract (200 mg/kg). The chromatographic separation was performed on a C18 column using acetonitrile-aqueous 0.1% formic acid (90:10, v/v) as the mobile phase. Plasma samples were prepared for analysis using a simple liquid-liquid extraction with ethyl acetate. Analytes were detected using tandem mass spectrometry in positive multiple reaction monitoring mode. Method validation revealed excellent linearity over the range 1.25-900 ng/mL for 5-hydroxy-4-methoxycanthin-6-one and 0.5-800 ng/mL for 4,5-dimethoxycanthin-6-one with satisfactory intra- and inter-day precision, accuracy and recovery. Samples were stable under the conditions tested. The pharmacokinetic profiles of the analytes in rats showed that both canthinones were rapidly absorbed and that 4,5-dimethoxycanthin-6-one was eliminated faster than 5-hydroxy-4-methoxycanthin-6-one.

  3. Simultaneous quantification of five steroid saponins from Dioscorea zingiberensis C.H. Wright in rat plasma by HPLC-MS/MS and its application to the pharmacokinetic studies.

    PubMed

    Zhang, Xinxin; Li, Jing; Ito, Yoichiro; Sun, Wenji

    2015-01-01

    A simple, reliable and sensitive high-performance liquid chromatography tandem mass spectrometry method (HPLC-MS/MS) was established for simultaneous analyses of the following 5 steroid saponins in rat plasma after the single dose administration of total steroid saponins extracted from the rhizome of Dioscorea zingiberensis C.H. Wright for the first time. Protodioscin, huangjiangsu A, zingiberensis new saponin, dioscin, and gracillin were quantified using ginsenoside Rb1 as the internal standard (IS). The plasma samples were pretreated by a single step acetonitrile-mediated protein precipitation. The chromatographic separation was performed on an Inersil ODS-3 C18 column (250mm×4.6mm, 5μm) with the mobile phase composed of acetonitrile and water containing 0.1% formic acid under a gradient elution mode at 0.2mLmin(-1) using a microsplit after the eluent from the HPLC apparatus. The quantification was accomplished on a triple quadrupole tandem mass spectrometer using the multiple reaction monitoring (MRM) in the positive ionization mode. The above five analytes were stable under sample storage and preparation conditions applied in the present study. The linearity, precision, accuracy, and recoveries of the analysis confirmed the requirements for quality-control purposes. After validation, this proposed method was successfully adopted to investigate the pharmacokinetic parameters of these five analytes.

  4. Laser produced plasma diagnostics by cavity ringdown spectroscopy and applications

    SciTech Connect

    Milosevic, S.

    2012-05-25

    Laser-produced plasmas have many applications for which detailed characterization of the plume is requested. Cavity ring-down spectroscopy is a versatile absorption method which provides data on the plume and its surroundings, with spatial and temporal resolution. The measured absorption line shapes contain information about angular and velocity distributions within the plume. In various plasmas we have observed molecules or metastable atoms which were not present in the emission spectra.

  5. Simultaneous bioanalysis of rasagiline and its major metabolites in human plasma by LC-MS/MS: Application to a clinical pharmacokinetic study.

    PubMed

    Wang, Ting; Yang, Leting; Hua, Jing; Xie, Huiru; Jiang, Xuehua; Wang, Ling

    2016-06-01

    Rasagiline is a selective, irreversible inhibitor of monoamine oxidase type-B (MAO-B) and has been used both as a monotherapy and in addition to levodopa in the treatment of Parkinson's disease (PD). Rasagiline is metabolized by the cytochrome P450 (CYP) system, and the following three major metabolites with potential neuroprotective activity have been identified: 1-aminoindan (AI), 3-hydroxy-N-propargyl-1-aminoindan (3-OH-PAI) and 3-hydroxy-1-aminoindan (3-OH-AI). In this study, a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of rasagiline and its major metabolites in human plasma. This method was validated in terms of specificity, linearity, precision, accuracy, recovery, matrix effect and stability. The validated method was then applied to a clinical pharmacokinetic study after the oral administration of 1mg rasagiline mesylate tablets to six healthy Chinese volunteers. PMID:27060436

  6. Clinical and Biological Principles of Cold Atmospheric Plasma Application in Skin Cancer.

    PubMed

    Gay-Mimbrera, Jesús; García, Maria Carmen; Isla-Tejera, Beatriz; Rodero-Serrano, Antonio; García-Nieto, Antonio Vélez; Ruano, Juan

    2016-06-01

    Plasma-based electrosurgical devices have long been employed for tissue coagulation, cutting, desiccation, and cauterizing. Despite their clinical benefits, these technologies involve tissue heating and their effects are primarily heat-mediated. Recently, there have been significant developments in cold atmospheric pressure plasma (CAP) science and engineering. New sources of CAP with well-controlled temperatures below 40 °C have been designed, permitting safe plasma application on animal and human bodies. In the last decade, a new innovative field, often referred to as plasma medicine, which combines plasma physics, life science, and clinical medicine has emerged. This field aims to exploit effects of mild plasma by controlling the interactions between plasma components (and other secondary species that can be formed from these components) with specific structural elements and functionalities of living cells. Recent studies showed that CAP can exert beneficial effects when applied selectively in certain pathologies with minimal toxicity to normal tissues. The rapid increase in new investigations and development of various devices for CAP application suggest early adoption of cold plasma as a new tool in the biomedical field. This review explores the latest major achievements in the field, focusing on the biological effects, mechanisms of action, and clinical evidence of CAP applications in areas such as skin disinfection, tissue regeneration, chronic wounds, and cancer treatment. This information may serve as a foundation for the design of future clinical trials to assess the efficacy and safety of CAP as an adjuvant therapy for skin cancer.

  7. Dressed electrostatic solitary excitations in three component pair-plasmas: Application in isothermal pair-plasma with stationary ions

    SciTech Connect

    Esfandyari-Kalejahi, A.; Akbari-Moghanjoughi, M.; Haddadpour-Khiaban, B.

    2009-10-15

    In this work electrostatic solitary waves in a three component pair-plasma consisting of hot isothermal electrons (or negative fullerene ions), positrons (or positive fullerene ions), and stationary positive ions (say, dust particulates) are studied. Using reductive perturbation method, plasma fluid equations are reduced to a Korteweg-de Vries (KdV) equation. Considering the higher-order nonlinearity, a linear inhomogeneous equation is derived, and the stationary solutions of these coupled equations are achieved by applying the renormalization procedure of Kodama-Taniuti. It is observed that in the linear approximation and applying Fourier analysis, two electrostatic modes, namely, upper or optical and lower or acoustic modes, are present. However, the application of reductive perturbation technique confirms that only acoustic-electrostatic mode can propagate in such plasma as KdV soliton, the amplitude and width of which are studied regarding to plasma parameters {sigma} (positron-to-electron temperature ratio) and {delta} (stationary cold ions-to-electron density ratio). It is also observed that the higher-order nonlinearity leads to deformation of the soliton structure from bell-shaped to W-shaped depending on the variation in values of the plasma parameters {sigma} and {delta}. It is revealed that KdV-type solitary waves cannot propagate in three component pair-plasma when the pair-species temperature is equal.

  8. Application of non-equilibrium plasmas in treatment of wool fibers and seeds

    NASA Astrophysics Data System (ADS)

    Petrović, Zoran

    2003-10-01

    While large effort is under way to achieve stable, large area, non-equilibrium plasma reactors operating at atmospheric pressure we should still consider application of low pressure reactors, which provide well defined, easily controlled reactive plasmas. Therefore, the application of low pressure rf plasmas for the treatment of wool and seed was investigated. The studies were aimed at establishing optimal procedure to achieve better wettability, dyeability and printability of wool. Plasma treatment led to a modification of wool fiber topography and formation of new polar functional groups inducing the increase of wool hydrophylicity. Plasma activation of fiber surface was also used to achieve better binding of biopolymer chitosan to wool in order to increase the content of favorable functional groups and thus improving sorption properties of recycled wool fibers for heavy metal ions and acid dyes. In another study, the increase of germination percentage of seeds induced by plasmas was investigated. We have selected dry (unimbibed) Empress tree seeds (Paulownia tomentosa Steud.). Empress tree seed has been studied extensively and its mechanism of germination is well documented. Germination of these seeds is triggered by light in a limited range of wavelengths. Interaction between activated plasma particles and seed, inside the plasma reactor, leads to changes in its surface topography, modifies the surface layer and increases the active surface area. Consequently, some bioactive nitrogeneous compounds could be bound to the activated surface layer causing the increment of germination percentage.

  9. Application of Atmospheric-Pressure Microwave Line Plasma for Low Temperature Process

    NASA Astrophysics Data System (ADS)

    Suzuki, Haruka; Nakano, Suguru; Itoh, Hitoshi; Sekine, Makoto; Hori, Masaru; Toyoda, Hirotaka

    2015-09-01

    Atmospheric pressure (AP) plasmas have been given much attention because of its high cost benefit and a variety of possibilities for industrial applications. In various kinds of plasma production technique, pulsed-microwave discharge plasma using slot antenna is attractive due to its ability of high-density and stable plasma production. In this plasma source, however, size of the plasma has been limited up to a few cm in length due to standing wave inside a waveguide. To solve this, we have proposed a newly-developed AP microwave plasma source that utilizes not standing wave but travelling wave. By using this plasma source, spatially-uniform AP line plasma with 40 cm in length was realized by pure helium discharge in 60 cm slot and with nitrogen gas additive of 1%. Furthermore, gas temperature as low as 400 K was realized in this device. In this study, as an example of low temperature processes, hydrophilic treatment of PET films was performed. Processing speed increased with pulse frequency and a water contact angle of ~20° was easily obtained within 5 s with no thermal damage to the substrate. To evaluate treatment-uniformity of long line length, PET films were treated by 90 cm slot-antenna plasma and uniform treatment performance was confirmed.

  10. Dust dynamics and diagnostic applications in quasi-neutral plasmas and magnetic fusion

    NASA Astrophysics Data System (ADS)

    Wang, Zhehui; Ticos, Catalin M.; Si, Jiahe; Delzanno, Gian Luca; Lapenta, Gianni; Wurden, Glen

    2007-11-01

    Little is known about dust dynamics in highly ionized quasi-neutral plasmas with ca. 1.0 e+20 per cubic meter density and ion temperature at a few eV and above, including in magnetic fusion. For example, dust motion in fusion, better known as UFO's, has been observed since 1980's but not explained. Solid understanding of dust dynamics is also important to International Thermonuclear Experimental Reactor (ITER) because of concerns about safety and dust contamination of fusion core. Compared with well studied strongly-coupled dusty plasma regime, new physics may arise in the higher density quasi-neutral plasma regime because of at least four orders of magnitude higher density and two orders of magnitude hotter ion temperature. Our recent laboratory experiments showed that plasma-flow drag force dominates over other forces in a quasi-neutral flowing plasma. In contrast, delicate balance among different forces in dusty plasma has led to many unique phenomena, in particular, the formation of dust crystal. Based on our experiments, we argue that 1) dust crystal will not form in the highly ionized plasmas with flows; 2) the UFO's are moving dust dragged by plasma flows; 3) dust can be used to measure plasma flow. Two diagnostic applications using dust for laboratory quasi-neutral plasmas and magnetic fusion will also be presented.

  11. Low Temperature Atmospheric Argon Plasma: Diagnostics and Medical Applications

    NASA Astrophysics Data System (ADS)

    Ermolaeva, Svetlana; Petrov, Oleg; Zigangirova, Nailya; Vasiliev, Mikhail; Sysolyatina, Elena; Antipov, Sergei; Alyapyshev, Maxim; Kolkova, Natalia; Mukhachev, Andrei; Naroditsky, Boris; Shimizu, Tetsuji; Grigoriev, Anatoly; Morfill, Gregor; Fortov, Vladimir; Gintsburg, Alexander

    This study was devoted to diagnostic of low temperature plasma produced by microwave generator and investigation of its bactericidal effect against bacteria in biofilms and within eukaryotic cells. The profile of gas temperature near the torch outlet was measured. The spectrum in a wide range of wavelengths was derived by the method of optical emission spec-troscopy. Probe measurements of the floating potential of plasma were car-ried out. The estimation and adaptation of parameters of plasma flow (tem-perature, velocity, ion number density) according to medico-technical requirements were produced. The model of immersed surface-associated biofilms formed by Gram-negative bacteria, Pseudomonas aeruginosa and Burkholderia cenocepacia, and Gram-positive bacteria, Staphylococcus aureus, was used to assess bactericidal effects of plasma treatment. Reduction in the concentration of live bacteria in biofilms treated with plasma for 5 min was demonstrated by measuring Live/Dead fluorescent labeling and using direct plating. The intracellular infection model with the pathogenic bacterium, Chlamydia trachomatis, was used to study the efficacy of microwave argon plasma against intracellular parasites. A 2 min plasma treatment of mouse cells infected with C. trachomatis reduced infectious bacteria by a factor of 2×106. Plasma treatment diminished the number of viable host cells by about 20%. When the samples were covered with MgF2 glass to obstruct active particles and UV alone was applied, the bactericidal effect was re-duced by 5×104 fold compared to the whole plasma.

  12. Simultaneous determination of Eleutheroside B and Eleutheroside E in rat plasma by high performance liquid chromatography-electrospray ionization mass spectrometry and its application in a pharmacokinetic study.

    PubMed

    Ma, Bo; Zhang, Qi; Liu, Yinhui; Li, Jing; Xu, Qiuyu; Li, Xiaotian; Yang, Xiaojing; Yao, Di; Sun, Jingjing; Cui, Guangbo; Ying, Hanjie

    2013-02-15

    Eleutheroside B and Eleutheroside E, two kinds of the major bioactive saponins of Eleutherococcus senticosus, play a pivotal role in biologic activity. In this study, a specific and sensitive high performance liquid chromatography-electrospray ionization-tandem mass spectrometry method (HPLC-MS/MS) was developed and validated for simultaneous determination of Eleutheroside B and Eleutheroside E in rat plasma. The analytes were extracted from rat plasma via a simple protein precipitation procedure with methanol and polygonin was used as internal standard. Chromatographic separation was achieved on a C18 column using a gradient elution program with acetonitrile and water containing 0.1% ammonium hydroxide solution as the mobile phase, with a flow rate of 0.2mL/min. The detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reactions monitoring (MRM) mode in a negative ion mode via electrospray ionization (ESI). The transition monitored were m/z 371 [M-H](-)→209 for Eleutheroside B, m/z 741[M-H](-)→579 for Eleutheroside E and m/z 389[M-H](-)→277 for internal standard. Linear calibration curves were obtained in the concentration range of 1-2000ng/mL for both (Eleutheroside B and Eleutheroside E), with a lower limit of quantification of 1ng/mL. Extraction recovery was over 80% in plasma. The intra- and inter-day precision (RSD) values were below 12% and accuracy (RE) was -2.80 to 5.70% at three QC levels for both. The assay was successfully applied to study pharmacokinetics behavior in rats after oral and intravenous administration of the single substances (Eleutheroside B and Eleutheroside E). And further research was performed by comparing the difference in pharmacokinetic behavior between the single substances and an aqueous extract of E. senticosus after oral administration. Significant difference in pharmacokinetic characteristics between the single substances and an aqueous extract was found in rat, which would be beneficial for

  13. Formation of Imploding Plasma Liners for HEDP and MIF Application

    SciTech Connect

    Witherspoon, F. Douglas; Case, Andrew; Brockington, Samuel; Messer, Sarah; Bomgardner, Richard; Phillips, Mike; Wu, Linchun; Elton, Ray

    2014-11-11

    Plasma jets with high density and velocity have a number of important applications in fusion energy and elsewhere, including plasma refueling, disruption mitigation in tokamaks, magnetized target fusion, injection of momentum into centrifugally confined mirrors, plasma thrusters, and high energy density plasmas (HEDP). In Magneto-Inertial Fusion (MIF), for example, an imploding material liner is used to compress a magnetized plasma to fusion conditions and to confine the resulting burning plasma inertially to obtain the necessary energy gain. The imploding shell may be solid, liquid, gaseous, or a combination of these states. The presence of the magnetic field in the target plasma suppresses thermal transport to the plasma shell, thus lowering the imploding power needed to compress the target to fusion conditions. This allows the required imploding momentum flux to be generated electromagnetically using off-the-shelf pulsed power technology. Practical schemes for standoff delivery of the imploding momentum flux are required and are open topics for research. One approach for accomplishing this, called plasma jet driven magneto-inertial fusion (PJMIF), uses a spherical array of pulsed plasma guns to create a spherically imploding shell of very high velocity, high momentum flux plasma. This approach requires development of plasma jet accelerators capable of achieving velocities of 50-200 km/s with very precise timing and density profiles, and with high total mass and density. Low-Z plasma jets would require the higher velocities, whereas very dense high-Z plasma shells could achieve the goal at velocities of only 50-100 km/s. In this report, we describe our work to develop the pulsed plasma gun technology needed for an experimental scientific exploration of the PJMIF concept, and also for the other applications mentioned earlier. The initial goal of a few hundred of hydrogen at 200 km/s was eventually replaced with accelerating 8000 μg of argon or xenon to 50 km

  14. Topics in high voltage pulsed power plasma devices and applications

    NASA Astrophysics Data System (ADS)

    Chen, Hao

    Pulsed power technology is one of the tools that is used by scientists and engineers nowadays to produce gas plasmas. The transient ultra high power is able to provide a huge pulse of energy which is sometimes greater than the ionization energy of the gas, and therefore separates the ions and electrons to form the plasma. Sometimes, the pulsed power components themselves are plasma devices. For example, the gas type switches can "turn on" the circuit by creating the plasma channel between the switch electrodes. Mini Back Lighted Thyratron, or as we call it, mini-BLT, is one of these gas type plasma switches. The development of the reduced size and weight "mini-BLT" is presented in this dissertation. Based on the operation characteristics testing of the mini-BLT, suggestions of optimizing the design of the switch are proposed. All the factors such as the geometry of the hollow electrodes and switch housing, the gas condition, the optical triggering source, etc. are necessary to consider when we design and operate the mini-BLT. By reducing the diameter of the cylindrical gas path between the electrodes in the BLT, a novel high density plasma source is developed, producing the plasma in the "squeezed" capillary. The pulsed power generator, of course, is inevitably used to provide the ionization energy for hydrogen gas sealed in the capillary. Plasma diagnostics are necessarily analyzed and presented in detail to properly complete and understand the capillary plasma. This high density plasma source (1019 cm-3) has the potential applications in the plasma wakefield accelerator. The resonant oscillation behavior of the particles in plasmas allows for dynamically generated accelerating electric fields that have orders of magnitude larger than those available in the conventional RF accelerators. Finally, the solid state switches are introduced as a comparison to the gas type switch. Pulsed power circuit topologies such as the Marx Bank, magnetic pulse compression and diode

  15. Development of a simple LC-MS/MS method for the determination of febuxostat in human plasma and its application to a bioequivalence study.

    PubMed

    Shi, Zheng; Liu, Jian; Hu, Xing-Jiang; ShenTu, Jian-Zhong

    2013-06-01

    The purpose of this study was to design a simple, sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for a febuxostat bioequivalence study in healthy Chinese male volunteers. In this method, febuxostat and etodolac (internal standard) were isolated from plasma samples by protein precipitation with acetonitrile. The supernatant was chromatographed on a Zorbax SB-C18 (150 x 3.0 mm, 3.5-microm particle size, Agilent) column with a SecurityGuard Inertsil Symmetry C18 column (12.5 x 4.6 mm, 5-microm particle size, Waters). The lower limit of quantification for febuxostat in 0.2 mL of human plasma was 13.40 ng x mL(-1), and the linearity was achieved over a concentration range from 13.40 to 21440 ng x mL(-1). Febuxostat tablets from Hengrui Medicine Co., Ltd (test, Jiangsu, China) and from Takeda pharmaceuticals america, Inc. (reference, Deerfield, IL) were evaluated following a single 80 mg oral dose to 18 healthy volunteers. Bioequivalence was determined by calculating 90% confidence intervals (90% CI) for the ratio of C(max), AUC(0-t), and AUC(0-infinity) values for the test and reference products, using logarithmic transformed data. The calculated 90% CIs for the ratio of C(max) (88.7-131.2%), AUC(0-t) (99.2-122.7%) and AUC(0-infinity) (99.5-123.1%) values for the test and reference products were all located within the bioequivalence criteria range (80-125% for AUC, and 70-143% for Ca(mzax)), proposed by State of Food and Drug Administration [SFDA, 2005. China]. It was concluded that the two febuxostat formulations (test and reference) analyzed were bioequivalent in terms of rate and extent of absorption and the method met the principle of quick and easy clinical analysis.

  16. Effects of plasma on polyethylene fiber surface for prosthodontic application

    PubMed Central

    SPYRIDES, Silvana Marques Miranda; do PRADO, Maíra; de ARAUJO, Joyce Rodrigues; SIMÃO, Renata Antoun; BASTIAN, Fernando Luis

    2015-01-01

    ABSTRACT Plasma technology has the potential to improve the adherence of fibers to polymeric matrices, and there are prospects for its application in dentistry to reinforce the dental particulate composite. Objectives This study aimed to investigate the effect of oxygen or argon plasma treatment on polyethylene fibers. Material and Methods Connect, Construct, InFibra, and InFibra treated with oxygen or argon plasma were topographically evaluated by scanning electron microscopy (SEM), and chemically by X-ray photoelectron spectroscopy (XPS). For bending analysis, one indirect composite (Signum) was reinforced with polyethylene fiber (Connect, Construct, or InFibra). The InFibra fiber was subjected to three different treatments: (1) single application of silane, (2) oxygen or argon plasma for 1 or 3 min, (3) oxygen or argon plasma and subsequent application of silane. The samples (25x2x2 mm), 6 unreinforced and 60 reinforced with fibers, were subjected to three-point loading tests to obtain their flexural strength and deflection. The results were statistically analyzed with ANOVA and the Bonferroni correction for multiple comparison tests. Results SEM analysis showed that oxygen and argon plasma treatments promote roughness on the polyethylene fiber surface. X-ray photoelectron spectroscopy (XPS) analysis shows that both plasmas were effective in incorporating oxygenated functional groups. Argon or oxygen plasma treatment affected the flexural strength and deflection of a fiber reinforced composite. The application of silane does not promote an increase in the flexural strength of the reinforced composites. Conclusions Oxygen and argon plasma treatments were effective in incorporating oxygenated functional groups and surface roughness. The highest strength values were obtained in the group reinforced with polyethylene fibers treated with oxygen plasma for 3 min. PMID:26814463

  17. Plasma edge studies using carbon resistance probes

    SciTech Connect

    Wampler, W.R.; Manos, D.M.

    1983-04-01

    A new experimental technique, the resistance probe, was used to study the plasma edge in the PLT and PDX tokamaks. This technique involves measuring the change in resistance of a thin carbon film due to bombardment by energetic particles escaping the plasma. The probes have been calibrated by measuring the resistance change caused by implantation of various ions at different energies. A model has been developed which can be used to determine the flux and energy of the incident particles from the measured resistance changes. For probes exposed in PDX and PLT near the wall, resistance changes were observed due to charge exchange neutrals. Larger changes were observed in the ion scrape-off region closer to the plasma. In PLT the effect of ions at the plasma edge begins to dominate the neutral flux near the radius of the ring limiter. The energy of ions at the plasma edge was estimated to be low (< or approx. =100 eV) in PDX during neutral beam-heated discharges, but higher (> or approx. =300 eV) in PLT during ion cyclotron resonance heating.

  18. Feasibility Study for a Plasma Dynamo Facility to Investigate Fundamental Processes in Plasma Astrophysics. Final report

    SciTech Connect

    Forest, Cary B.

    2013-09-19

    The scientific equipment purchased on this grant was used on the Plasma Dynamo Prototype Experiment as part of Professor Forest's feasibility study for determining if it would be worthwhile to propose building a larger plasma physics experiment to investigate various fundamental processes in plasma astrophysics. The initial research on the Plasma Dynamo Prototype Experiment was successful so Professor Forest and Professor Ellen Zweibel at UW-Madison submitted an NSF Major Research Instrumentation proposal titled "ARRA MRI: Development of a Plasma Dynamo Facility for Experimental Investigations of Fundamental Processes in Plasma Astrophysics." They received funding for this project and the Plasma Dynamo Facility also known as the "Madison Plasma Dynamo Experiment" was constructed. This experiment achieved its first plasma in the fall of 2012 and U.S. Dept. of Energy Grant No. DE-SC0008709 "Experimental Studies of Plasma Dynamos," now supports the research.

  19. Simultaneous determination of six flavonoids from Paulownia tomentosa flower extract in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Dai, Bin; Hu, Zhiqiang; Li, Haiyan; Yan, Chong; Zhang, Liwei

    2015-01-26

    A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of six components including apigenin, quercetin, apigenin-7-O-β-D-glucoside, quercetin-3-O-β-D-glucoside, 3'-methoxyluteolin-7-O-β-D-glucoside, and tricin-7-O-β-D-glucopyranoside in rat plasma using formononetin as the internal standard (IS). The plasma samples were pretreated by a one-step liquid-liquid extraction with dichloromethane. The chromatographic separation was carried out on a ZORBAX SB-Aq column with a gradient mobile phase consisting of acetonitrile and 2mM aqueous ammonium acetate. All analytes and IS were quantitated through electrospray ionization in negative ion multiple reaction monitoring mode. The mass transitions were as follows: m/z 269.1→117.2 for apigenin, m/z 301.2→151.2 for quercetin, m/z 431.3→311.2 for apigenin-7-O-β-D-glucoside, m/z 463.2→300.2 for quercetin-3-O-β-D-glucoside, m/z 461.3→283.1 for 3'-methoxyluteolin-7-O-β-D-glucoside, m/z 491.3→313.1 for tricin-7-O-β-D-glucopyranoside, and m/z 267.2→252.2 for IS, respectively. All calibration curves exhibited good linearity with correlation coefficient (r)>0.995. The intra-day and inter-day precisions (RSD) at three QC levels were both less than 14.0% and the accuracies ranged from 89.8% to 113.8%. The extraction recoveries of six compounds ranged from 82.3% to 92.5%. The validated method was successfully applied to pharmacokinetic study of the six components in male rat plasma after oral administration of Paulownia tomentosa flower extract. PMID:25531870

  20. Simultaneous Determination of Bosentan, Glimepiride, HYBOS and M1 in Rat Plasma by UPLC-MS-MS and its Application to Pharmacokinetic Study.

    PubMed

    Chen, Mengchun; Song, Wenjie; Wang, Shuanghu; Chen, Qiulei; Pan, Peipei; Xu, Tao; Hu, Guoxin; Zheng, Zhiqiang

    2016-08-01

    A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method for the simultaneous determination of bosentan (BOS), glimepiride (GLP), hydroxyl bosentan (HYBOS) and hydroxyl glimepiride (M1) in rat plasma using one-step protein precipitation was developed and validated. After addition of ambrisentan as an internal standard (IS), protein precipitation by acetonitrile was used in sample preparation. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C18 column (2.1 mm × 100 mm, 1.7 μm particle size, Waters Corp., Milford, MA, USA) and inline 0.2 μm stainless steel frit filter (Waters Corp.) with acetonitrile-0.1% formic acid as the mobile phase at a flow rate of 0.4 mL/min with gradient elution. The column temperature was maintained at 40°C. Only 4 min was needed for an analytical run. The retention times were ∼3.29 min for BOS, 3.56 min for GLP, 1.42 min for HYBOS, 1.53 min for M1 and 3.22 min for IS. Electrospray ionization source was employed and operated in positive-ion mode; multiple reaction monitoring mode was applied to target fragment ions m/z 552 → 202, m/z 568 → 202, m/z 491 → 352, m/z 507 → 352 and m/z 379 → 347 for BOS, HYBOS, GLP, M1 and IS, respectively. The assay was validated over concentration ranges of 25-5,000 ng/mL (r(2) = 0.9984) for BOS, 1-200 ng/mL (r(2) = 0.9999) for GLP, 0.5-100 ng/mL (r(2) = 0.9999) for HYBOS and 0.1-20 ng/mL (r(2) = 0.9984) for M1. Intra- and interday precision values for replicate quality control samples were within 14.2% for all analytes during the assay validation. Mean quality control accuracy values were within -3.3 to 14.4% of nominal values for all analytes. The mean recoveries of BOS, GLP, HYBOS, M1 and ambrisentan from the plasma exceeded 90.4%. The analytes were stable in rat plasma for at least 2 h at room temperature, 30 days at -40°C and following at least three freeze-thaw cycles (-40°C to room temperature). This method was

  1. Laboratory study of avalanches in magnetized plasmas.

    PubMed

    Van Compernolle, B; Morales, G J; Maggs, J E; Sydora, R D

    2015-03-01

    It is demonstrated that a novel heating configuration applied to a large and cold magnetized plasma allows the study of avalanche phenomena under controlled conditions. Intermittent collapses of the plasma pressure profile, associated with unstable drift-Alfvén waves, exhibit a two-slope power-law spectrum with exponents near -1 at lower frequencies and in the range of -2 to -4 at higher frequencies. A detailed mapping of the spatiotemporal evolution of a single avalanche event is presented. PMID:25871044

  2. Application of Platelet Rich Plasma in Sports Medicine

    PubMed Central

    Ficek, Krzysztof; Kamiński, Tomasz; Wach, Ewa; Cholewiński, Jerzy; Cięszczyk, Paweł

    2011-01-01

    Any new method of treatment is associated with high expectations for its success, particularly if the therapy is based not only on the premise of achieving a symptomatic effect, but also improving functional quality and repairing structurally damaged tissues. Platelet Rich Plasma (PRP) application was shown to be a successful catalyst in the healing process for a wide variety of conditions in animal and human models. However, its use has been controversial due to many types of the PRP definition, optimal concentration, and modalities of implementation. In the qualification of patients for PRP treatment, not only should medical indications be considered, but also the role of participation in therapy with a physiotherapist supervising physical parameters and techniques used during recovery time. Further study is required in order to define optimal handling procedures of PRP injection. Long-term follow up will reveal if the promise of this substance can be realized and implemented to maximize its potential as a therapeutic remedy. PMID:23487362

  3. Electrical studies and plasma characterization of an atmospheric pressure plasma jet operated at low frequency

    SciTech Connect

    Giuliani, L.; Xaubet, M.; Grondona, D.; Minotti, F.; Kelly, H.

    2013-06-15

    Low-temperature, high-pressure plasma jets have an extensive use in medical and biological applications. Much work has been devoted to study these applications while comparatively fewer studies appear to be directed to the discharge itself. In this work, in order to better understand the kind of electrical discharge and the plasma states existing in those devices, a study of the electrical characteristics of a typical plasma jet, operated at atmospheric pressure, using either air or argon, is reported. It is found that the experimentally determined electrical characteristics are consistent with the model of a thermal arc discharge, with a highly collisional cathode sheet. The only exception is the case of argon at the smallest electrode separation studied, around 1 mm in which case the discharge is better modeled as either a non-thermal arc or a high-pressure glow. Also, variations of the electrical behavior at different gas flow rates are interpreted, consistently with the arc model, in terms of the development of fluid turbulence in the external jet.

  4. Spectroscopic studies of non-thermal plasma jet at atmospheric pressure formed in low-current nonsteady-state plasmatron for biomedical applications

    NASA Astrophysics Data System (ADS)

    Demkin, V. P.; Melnichuk, S. V.; Demkin, O. V.; Kingma, H.; Van de Berg, R.

    2016-04-01

    The optical and electrophysical characteristics of the nonequilibrium low-temperature plasma formed by a low-current nonsteady-state plasmatron are experimentally investigated in the present work. It is demonstrated that experimental data on the optical diagnostics of the plasma jet can provide a basis for the construction of a self-consistent physical and mathematical plasma model and for the creation of plasma sources with controllable electrophysical parameters intended for the generation of the required concentration of active particles. Results of spectroscopic diagnostics of plasma of the low-current nonsteady-state plasmatron confirm that the given source is efficient for the generation of charged particles and short-wavelength radiation—important plasma components for biomedical problems of an increase in the efficiency of treatment of biological tissues by charged particles. Measurement of the spatial distribution of the plasma jet potential by the probe method has demonstrated that a negative space charge is formed in the plasma jet possibly due to the formation of electronegative oxygen ions.

  5. Quantification of trabectedin in human plasma: validation of a high-performance liquid chromatography-mass spectrometry method and its application in a clinical pharmacokinetic study.

    PubMed

    Zangarini, Monique; Ceriani, Laura; Sala, Federica; Marangon, Elena; Bagnati, Renzo; D'Incalci, Maurizio; Grosso, Federica; Zucchetti, Massimo

    2014-07-01

    A rapid, sensitive and specific HPLC-MS/MS method was developed and validated for the quantification of trabectedin in human plasma after using deuterated trabectedin as Internal Standard (IS). After the addition of ammonium sulphate, the analyte was extracted from human plasma with acidified methanol (0.1 M HCl). Chromatographic separation was done on an Accucore XL C₁₈ column (4 μm; 50 mm × 2.1 mm) using a Mobile Phase (MP) consisting of CH₃COONH₄ 10 mM, pH 6.8 (MP A) and CH₃OH (MP B). The mass spectrometer worked with electrospray ionization in positive ion mode and Selected Reaction Monitoring (SRM), using target ions at [M-H₂O+H]⁺ m/z 744.4 for trabectedin and [M-H₂O+H]⁺m/z 747.5 for the IS. The standard curve was linear (R² ≥ 0.9955) over the concentration range 0.025-1.0 ng/ml and had good back-calculated accuracy and precision. The intra- and inter-day precision and accuracy determined on three quality control samples (0.04, 0.08 and 0.80 ng/ml) were <9.9% and between 98.3% and 105.3%, respectively. The extraction recovery was >81% and the lower limit of quantification 0.025 ng/ml. The method was successfully applied to study trabectedin pharmacokinetics in a patient with a liposarcoma who received 1.3 mg/m² as a 24 h continuous i.v. infusion.

  6. Method development for quantification of the environmental neurotoxin annonacin in Rat plasma by UPLC-MS/MS and application to a pharmacokinetic study.

    PubMed

    Bonneau, Natacha; Schmitz-Afonso, Isabelle; Brunelle, Alain; Touboul, David; Champy, Pierre

    2015-11-01

    Annonacin is an environmental neurotoxin identified in the pulp of several fruits of the Annonaceae family (for example in Annona muricata, Asimina triloba), whose consumption was linked with the occurrence of sporadic atypical Parkinsonism with dementia. Pharmacokinetic parameters of this molecule are unknown. A method for its quantification in Rat plasma was developed, using its analogue annonacinone as an internal standard. Extraction from plasma was performed using ethylacetate with a good recovery. Quantification was performed by UPLC-MS/MS in SRM mode, based on the loss of the γ-methyl-γ-lactone (-112amu) from the sodium-cationized species [M+Na](+) of both annonacin and internal standard. The limit of quantification was 0.25ng/mL. Despite strong matrix effects, a good linearity was obtained over two distinct ranges 0.25-10ng/mL and 10-100ng/mL. The intra- and inter-day precisions (RSD) were lower than 10%, while accuracy was within ±10%. This method was applied to a pharmacokinetic study in the Rat. After oral administration of 10mg/kg annonacin, a Cmax of 7.9±1.5ng/mL was reached at Tmax 0.25h; T1/2 was 4.8±0.7h and apparent distribution volume was 387.9±64.6L. The bioavailability of annonacin was estimated to be 3.2±0.3% of the ingested dose.

  7. Development and validation of a UFLC-MS/MS method for the determination of anhydrosafflor yellow B in rat plasma and its application to pharmacokinetic study.

    PubMed

    Yue, Shijun; Wu, Liang; Qu, Cheng; Tang, Yuping; Jin, Yi; Li, Shujiao; Shen, Juan; Shi, Xuqin; Shan, Chenxiao; Cui, Xiaobing; Zhang, Li; Yang, Haijun; Qian, Li; Qian, Dawei; Duan, Jin-ao

    2015-10-15

    A sensitive ultrafast liquid chromatography coupled with triple quadrupole mass spectrometric (UFLC-MS/MS) method for the quantification of anhydrosafflor yellow B (AHSYB), a major active water-soluble pigment from Carthamus tinctorius, in rat plasma has been developed and validated. Sample preparation was achieved by protein precipitation of plasma with four volumes of methanol. Rutin was used as the internal standard (IS). The analytes were separated using a C18 column with an 8min gradient elution, followed by mass spectrometric detection using negative electrospray ionization (ESI(-)) in multiple reaction monitoring (MRM) mode. The method was linear in the concentration range of 25-10,000ng/mL for AHSYB. Intra-day and inter-day precision variation was less than 6.5%. The relative error of accuracy was within ±9.4%. The mean recovery of AHSYB was higher than 70.9%. The established method was successfully applied to the pharmacokinetic study after intravenous (2.5mg/kg) and oral (30mg/kg) dosing of AHSYB in normal rats. And the pharmacokinetic properties of AHSYB in rats with acute blood stasis and the differences between normal and acute blood stasis syndrome rats were also investigated. The results showed that the compound was poorly absorbed (∼0.3%) and the AUC0-t, AUC0-∞ and F were all significantly lower (P<0.05) in acute blood stasis syndrome rats, suggesting that disease condition may alter the body metabolism by enhancing metabolite enzyme activity. PMID:26409263

  8. Method Development and Validation of Montelukast in Human Plasma by HPLC Coupled with ESI-MS/MS: Application to a Bioequivalence Study

    PubMed Central

    Challa, Balasekhara Reddy; Awen, Bahlul Z.; Chandu, Babu Rao; Khagga, Mukkanti; Kotthapalli, Chandrasekhar Bannoth

    2010-01-01

    A simple, sensitive, and specific LC-ESI–MS/MS method for quantification of Montelukast (MO) in human plasma using Montelukast-d6 (MOD6) as an internal standard (IS) is discussed here. Chromatographic separation was performed on YMC-pack pro C18, 50 x 4.6 mm, S-3 μm column with an isocratic mobile phase composed of 10mM ammonium formate (pH 4.0):acetonitrile (20:80 v/v), at a flow-rate of 0.8 mL min−1. MO and MOD6 were detected with proton adducts at m/z 586.2→568.2 and 592.3→574.2 in multiple reaction monitoring (MRM) positive mode respectively. MO and MOD6 were extracted using acetonitrile as precipitating agent. The method was validated over a linear concentration range of 1.0–800.0 ng mL−1 with correlation coefficient (r2) ≥ 0.9996. The intraday precision and accuracy were within 1.91–7.10 and 98.32–99.17. The inter-day precision and accuracy were within 3.42–4.41% and 98.14–99.27% for MO. Both analytes were found to be stable throughout three freeze-thawing cycles, bench top, and autosampler stability studies. This method was utilized successfully for the analysis of plasma samples following oral administration of MO (5 mg) in 31 healthy Indian male human volunteers under fasting conditions. PMID:21179354

  9. Numerical Simulations of Plasma Based Flow Control Applications

    NASA Technical Reports Server (NTRS)

    Suzen, Y. B.; Huang, P. G.; Jacob, J. D.; Ashpis, D. E.

    2005-01-01

    A mathematical model was developed to simulate flow control applications using plasma actuators. The effects of the plasma actuators on the external flow are incorporated into Navier Stokes computations as a body force vector. In order to compute this body force vector, the model solves two additional equations: one for the electric field due to the applied AC voltage at the electrodes and the other for the charge density representing the ionized air. The model is calibrated against an experiment having plasma-driven flow in a quiescent environment and is then applied to simulate a low pressure turbine flow with large flow separation. The effects of the plasma actuator on control of flow separation are demonstrated numerically.

  10. Variable dual-frequency electrostatic wave launcher for plasma applications.

    PubMed

    Jorns, Benjamin; Sorenson, Robert; Choueiri, Edgar

    2011-12-01

    A variable tuning system is presented for launching two electrostatic waves concurrently in a magnetized plasma. The purpose of this system is to satisfy the wave launching requirements for plasma applications where maximal power must be coupled into two carefully tuned electrostatic waves while minimizing erosion to the launching antenna. Two parallel LC traps with fixed inductors and variable capacitors are used to provide an impedance match between a two-wave source and a loop antenna placed outside the plasma. Equivalent circuit analysis is then employed to derive an analytical expression for the normalized, average magnetic flux density produced by the antenna in this system as a function of capacitance and frequency. It is found with this metric that the wave launcher can couple to electrostatic modes at two variable frequencies concurrently while attenuating noise from the source signal at undesired frequencies. An example based on an experiment for plasma heating with two electrostatic waves is used to demonstrate a procedure for tailoring the wave launcher to accommodate the frequency range and flux densities of a specific two-wave application. This example is also used to illustrate a method based on averaging over wave frequencies for evaluating the overall efficacy of the system. The wave launcher is shown to be particularly effective for the illustrative example--generating magnetic flux densities in excess of 50% of the ideal case at two variable frequencies concurrently--with a high adaptability to a number of plasma dynamics and heating applications. PMID:22225213

  11. Risk assessment of the application of a plasma jet in dermatology

    NASA Astrophysics Data System (ADS)

    Lademann, Juergen; Richter, Heike; Alborova, Alena; Humme, Daniel; Patzelt, Alexa; Kramer, Axel; Weltmann, Klaus-Dieter; Hartmann, Bernd; Ottomann, Christian; Fluhr, Joachim W.; Hinz, Peter; Hübner, Georg; Lademann, Olaf

    2009-09-01

    Regardless of the fact that several highly efficient antiseptics are commercially available, the antiseptic treatment of chronic wounds remains a problem. In the past, electrical plasma discharges have been frequently used in biometrical science for disinfection and sterilization of material surfaces. Plasma systems usually have a temperature of several hundred degrees. Recently, it was reported that ``cold'' plasma can be applied onto living tissue. In in vitro studies on cell culture, it could be demonstrated that this new plasma possesses excellent antiseptic properties. We perform a risk assessment concerning the in vivo application of a ``cold'' plasma jet on patients and volunteers. Two potential risk factors, UV radiation and temperature, are evaluated. We show that the UV radiation of the plasma in the used system is an order of magnitude lower than the minimal erythema dose, necessary to produce sunburn on the skin in vivo. Additionally, thermal damage of the tissue by the plasma can be excluded. The results of the risk assessment stimulate the in vivo application of the investigated plasma jet in the treatment of chronic wounds.

  12. Theoretical and computational studies of plasma opening switches

    NASA Astrophysics Data System (ADS)

    Lindman, Erick L., Jr.; Kindel, Joseph M.

    1989-02-01

    Substantial progress has been made in understanding the operation of plasma opening switches (POS) in support of the Light-Ion Fusion Program at Sandia National Laboratories. Our efforts began with scoping studies using the particle-in-cell (PIC) code, MAGIC, which was written by Bruce Goplen and co-workers at MRC for pulsed-power applications. The version of MAGIC currently at Sandia National Laboratories is supported by Dave Seidel and Tim Pointon. MAGIC continues to play an important role as our studies moved into many different areas. Working closely with Cliff Mendel, we performed initial studies of switches using his fast B sub z concept. Working with Mary Ann Sweeney, Jeff Quintez and Cliff Mendel we performed studies of the effects of plasma density, cylindrical curvature, load impedance, rise time, and emission threshold on switch performance. In addition, we studied B-field penetration, turbulence, anomalous resistivity, and electron heating in plasma opening switches. This work has allowed us to identify the physical mechanisms that are important in the operation of plasma opening switches. Based on our knowledge of the physics we have established scaling relations for comparable switch performance under different experimental conditions. We studied the code requirements for POS simulation and numerical problems in MAGIC and in other PIC codes. And, more recently, we have begun to participate more strongly in the experimental program being carried out on PBFA II. Our conclusions based on these studies are summarized here.

  13. Theoretical and computational studies of plasma opening switches

    SciTech Connect

    Lindman, E.L. Jr.; Kindel, J.M.

    1989-02-01

    Substantial progress has been made in understanding the operation of plasma opening switches (POS) in support of the Light-Ion Fusion Program at Sandia National Laboratories. Our efforts began with scoping studies using the particle-in-cell (PIC) code, MAGIC, which was written by Bruce Goplen and co-workers at MRC for pulsed-power applications. The version of MAGIC currently at Sandia National Laboratories is supported by Dave Seidel and Tim Pointon. MAGIC continues to play an important role as our studies moved into many different areas. Working closely with Cliff Mendel, we performed initial studies of switches using his fast B/sub z/ concept. Working with Mary Ann Sweeney, Jeff Quintez and Cliff Mendel we performed studies of the effects of plasma density, cylindrical curvature, load impedance, rise time, and emission threshold on switch performance. In addition, we studied B-field penetration, turbulence, anomalous resistivity, and electron heating in plasma opening switches. This work has allowed us to identify the physical mechanisms that are important in the operation of plasma opening switches. Based on our knowledge of the physics we have established scaling relations for comparable switch performance under different experimental conditions. We studied the code requirements for POS simulation and numerical problems in MAGIC and in other PIC codes. And, more recently, we have begun to participate more strongly in the experimental program being carried out on PBFA II. Our conclusions based on these studies are summarized here. 42 refs., 104 figs., 3 tabs.

  14. Development and validation of a highly sensitive LC-MS/MS method for the determination of dexamethasone in nude mice plasma and its application to a pharmacokinetic study.

    PubMed

    Yuan, Yin; Zhou, Xuan; Li, Jian; Ye, Suofu; Ji, Xiwei; Li, Liang; Zhou, Tianyan; Lu, Wei

    2015-04-01

    In the current study, a simple, sensitive and rapid analytical method for the determination of dexamethasone was developed and applied to a pharmacokinetic study in nude mice. Using testosterone as an internal standard, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach after one-step precipitation with acetonitrile was validated and used to determine the concentrations of dexamethasone in nude mice plasma. The method utilized a simple isocratic reverse phase separation over a Dionex C18 column with a mobile phase composed of acetonitrile-water (40:60, v/v). The analyte was detected by a triple quadrupole tandem mass spectrometer via electrospray and multiple reaction monitoring was employed to select both dexamethasone at m/z 393.0/147.1 and testosterone at m/z 289.5/97.3 in the positive ion mode. The calibration curves were linear (r >0.99) ranging from 2.5 to 500 ng/mL with a lower limit of quantitation of 2.5 ng/mL. The relative standard deviation ranged from 1.69 to 9.22% while the relative error ranged from -1.92 to -8.46%. This method was successfully applied to a preclinical pharmacokinetic study of dexamethasone and its pharmacokinetics was characterized by a two-compartment model with first-order absorption in female nude mice.

  15. Development and Validation of Amisulpride in Human Plasma by HPLC Coupled with Tandem Mass Spectrometry and its Application to a Pharmacokinetic Study

    PubMed Central

    Mogili, Ramakotaiah; Kanala, Kanchanamala; Challa, Balasekhara Reddy; Chandu, Babu Rao; Bannoth, Chandrasekhar Kottapalli

    2011-01-01

    In this study, authors developed a simple, sensitive and specific liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for quantification of Amisulpride in human plasma using Amisulpride-d5 as an internal standard (IS). Chromatographic separation was performed on Zorbax Bonus-RP C18, 4.6 × 75 mm, 3.5 μm column with an isocratic mobile phase composed of 0.2% formic acid:methanol (35:65 v/v), at a flow-rate of 0.5 mL/min. Amisulpride, Amisulpride-d5 was detected at m/z 370.1→242.1 and 375.1→242.1. The drug and the IS were extracted by a liquid-liquid extraction method. The method was validated over a linear concentration range of 2.0–2500.0 ng/mL for Amisulpride with a correlation coefficient of (r2) ≥ 0.9982. This method demonstrated intra- and inter-day precision within 0.9 to 1.7 and 1.5 to 2.8 % and intra- and inter-day accuracy within 98.3 to 101.5 and 96.0 to 101.0 % for Amisulpride. Amisulpride was found to be stable at 3 freeze–thaw cycles, bench top and auto sampler stability studies. The developed method was successfully applied to a pharmacokinetic study. PMID:21886905

  16. Development and validation of amisulpride in human plasma by HPLC coupled with tandem mass spectrometry and its application to a pharmacokinetic study.

    PubMed

    Mogili, Ramakotaiah; Kanala, Kanchanamala; Challa, Balasekhara Reddy; Chandu, Babu Rao; Bannoth, Chandrasekhar Kottapalli

    2011-09-01

    In this study, authors developed a simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantification of Amisulpride in human plasma using Amisulpride-d(5) as an internal standard (IS). Chromatographic separation was performed on Zorbax Bonus-RP C18, 4.6 × 75 mm, 3.5 μm column with an isocratic mobile phase composed of 0.2% formic acid:methanol (35:65 v/v), at a flow-rate of 0.5 mL/min. Amisulpride, Amisulpride-d(5) was detected at m/z 370.1→242.1 and 375.1→242.1. The drug and the IS were extracted by a liquid-liquid extraction method. The method was validated over a linear concentration range of 2.0-2500.0 ng/mL for Amisulpride with a correlation coefficient of (r(2)) ≥ 0.9982. This method demonstrated intra- and inter-day precision within 0.9 to 1.7 and 1.5 to 2.8 % and intra- and inter-day accuracy within 98.3 to 101.5 and 96.0 to 101.0 % for Amisulpride. Amisulpride was found to be stable at 3 freeze-thaw cycles, bench top and auto sampler stability studies. The developed method was successfully applied to a pharmacokinetic study.

  17. Application of atmospheric pressure plasma in polymer and composite adhesion

    NASA Astrophysics Data System (ADS)

    Yu, Hang

    An atmospheric pressure helium and oxygen plasma was used to investigate surface activation and bonding in polymer composites. This device was operated by passing 1.0-3.0 vol% of oxygen in helium through a pair of parallel plate metal electrodes powered by 13.56 or 27.12 MHz radio frequency power. The gases were partially ionized between the capacitors where plasma was generated. The reactive species in the plasma were carried downstream by the gas flow to treat the substrate surface. The temperature of the plasm gas reaching the surface of the substrate did not exceed 150 °C, which makes it suitable for polymer processing. The reactive species in the plasma downstream includes ~ 1016-1017 cm-3 atomic oxygen, ~ 1015 cm-3 ozone molecule, and ~ 10 16 cm-3 metastable oxygen molecule (O2 1Deltag). The substrates were treated at 2-5 mm distance from the exit of the plasma. Surface properties of the substrates were characterized using water contact angle (WCA), atomic force microscopy (AFM), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS). Subsequently, the plasma treated samples were bonded adhesively or fabricated into composites. The increase in mechanical strength was correlated to changes in the material composition and structure after plasma treatment. The work presented hereafter establishes atmospheric pressure plasma as an effective method to activate and to clean the surfaces of polymers and composites for bonding. This application can be further expanded to the activation of carbon fibers for better fiber-resin interactions during the fabrication of composites. Treating electronic grade FR-4 and polyimide with the He/O2 plasma for a few seconds changed the substrate surface from hydrophobic to hydrophilic, which allowed complete wetting of the surface by epoxy in underfill applications. Characterization of the surface by X-ray photoelectron spectroscopy shows formation of oxygenated functional groups, including hydroxyl, carbonyl, and

  18. Simultaneous Analysis of Quercetin and Naringenin in Rat Plasma by Liquid Chromatography-Tandem Mass Spectrometry: Application to a Pharmacokinetic Study After Oral Administration.

    PubMed

    Ni, Boran; Cao, Sali; Feng, Lijun; Yin, Xingbin; Wang, Wenping; Zhang, Xin; Ni, Jian

    2016-09-01

    A rapid and specific LC-MS-MS method has been developed for simultaneous analysis of quercetin and naringenin in rat plasma. The method was applied to the pharmacokinetics studies of quercetin and naringenin after oral administration of Pollen Typhae extract. The samples were prepared by the protein precipitation method. The analysis was carried out on an ACQUITY UPLC™ BEH C18 column with gradient elution using mobile phase, which included acetonitrile and water (containing 0.1% formic acid). The flow rate was 0.4 mL/min. All analytes including internal standard (IS) were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for quercetin ranging from 0.5 to 100 ng/mL and naringenin ranging from 5 to 1000 ng/mL. The intra- and interday precisions (RSD) were less than 10.78 and 11.20%. The extraction recovery of the analytes was acceptable. Stability studies showed that quercetin and naringenin were stable in the preparation and analytical process. The validated method was successfully used to determine the concentration-time profiles of quercetin and naringenin. PMID:27199443

  19. Liquid chromatography-tandem mass spectrometry for the quantification of flurbiprofen in human plasma and its application in a study of bioequivalence.

    PubMed

    Mei, Chenghan; Li, Bin; Yin, Qiangfeng; Jin, Jing; Xiong, Ting; He, Wenjuan; Gao, Xiujuan; Xu, Rong; Zhou, Piqi; Zheng, Heng; Chen, Hui

    2015-07-01

    A simple, quick and accurate LC-MS/MS method for the quantification of flurbiprofen in human plasma with indomethacin as internal standard (IS) was developed and validated. Samples were treated with methanol to precipitate proteins, then separated on a Ultimate C18 column (5μm, 2.1×50mm) with a gradient elusion process. Mobile phase A was comprised of water and formic acid, mobile phase B was comprised of acetonitrile and formic acid. Multi reaction monitoring (MRM) signals were saved on a negative ionization electrospray mass spectrometer. The calibration curve showed good linearity in the range of 40.00-10000.00μg/L (r(2)=0.998). Intra-day RE was 0.2-2.2%. Inter-day RE was 0.5-3.4%. The samples showed good stability under the study conditions. No significant matrix effect was observed. The established method was then applied to a bioequivalence study of a flurbiprofen axetil formulation.

  20. Development, validation of liquid chromatography-tandem mass spectrometry method for simultaneous determination of rosuvastatin and metformin in human plasma and its application to a pharmacokinetic study.

    PubMed

    Kumar, P Pavan; Murthy, T E G K; Basaveswara Rao, M V

    2015-01-01

    A new, simple and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of rosuvastatin (ROS) and metformin (MET) in human plasma was developed. The assay procedure involved simple protein precipitation with acetonitrile. Following precipitation, fraction of supernatant was decanted and evaporated under gentle stream of nitrogen at 40°C. The residue was reconstituted in mobile phase and injected. The chromatographic separation was achieved with Thermo Hypurity C18 column (50 mm × 4.6 mm, 5 μ) using a mobile phase composition containing 0.1% v/v formic acid in water and acetonitrile (30:70, v/v) at a flow rate of 0.4 mL/min. The total run time was 3.5 min. The method showed good linearity in the range 0.5-200 ng/mL for ROS and 2-2000 ng/mL for MET with correlation coefficient (r) >0.9994 for both the analytes. The intra and inter-day precision values for ROS and MET met the acceptance criteria as per regulatory guidelines. The battery of stability studies viz., bench-top, freeze-thaw and long term stability were performed. The developed method was applied to a pharmacokinetic study. PMID:26317076

  1. Simultaneous determination of six phenolic constituents of Danshen injection in rat plasma by LC-ESI-MS and its application to a pharmacokinetic study.

    PubMed

    Zhao, Di; Han, De-en; Li, Ning; Lu, Yang; Li, Ting-ting; Yang, Suo-ye; He, Jia-ke; Chen, Xi-jing

    2011-01-01

    Salvianolic acid A, salvianolic acid B, danshensu, protocatechuic aldehyde, rosmarinic acid and lithospermic acid are the six major active constituents in Danshen injection. In this study, a rapid, sensitive and specific liquid chromatographic-electrospray ionization-mass spectrometry method for the simultaneous quantitative determination of these compounds in rat plasma was developed. After a single step of liquid-liquid extraction with ethyl acetate, they were eluted by a Hypersil C18 column (5 µm, i.d. 4.6 × 200 mm) within 4 min with a mobile phase consisting of acetonitrile and 0.1% formic acid water solution (35:65, v/v). The assay was linear in the concentration range of 0.05-10 µg mL(-1). Absolute recoveries were above 60%. The precisions and accuracies determined within three consecutive days were within acceptable limits. The method was successfully applied to a pharmacokinetic study in rats after an intravenous administration of Danshen injection. PMID:22006631

  2. Development of an LC/MS/MS method in order to determine arctigenin in rat plasma: its application to a pharmacokinetic study.

    PubMed

    Zou, Quanfei; Gu, Yuan; Lu, Rong; Zhang, Tiejun; Zhao, Guang-Rong; Liu, Changxiao; Si, Duanyun

    2013-09-01

    In this study, a simple and sensitive LC/MS/MS method was developed and validated for the determination of arctigenin in rat plasma. The MS detection was performed using multiple reaction monitoring at the transitions of m/z 373.2 → 137.3 for arctigenin and m/z 187.1 → 131.0 for psoralen (internal standard) with a Turbo IonSpray electrospray in positive mode. The calibration curves fitted a good linear relationship over the concentration range of 0.2-500 ng/mL. It was found that arctigenin is not stable enough at both room temperature and -80 °C unless mixed with methanol before storage. The validated LC/MS/MS method was successfully applied for the pharmacokinetic study of arctigenin in rats. After intravenous injection of 0.3 mg/kg arctigenin injection to rats, the maximum concentration, half-life and area under the concentration-time curve were 323 ± 65.2 ng/mL, 0.830 ± 0.166 and 81.0 ± 22.1 h ng/mL, respectively. PMID:23640910

  3. Validated LC-MS/MS method for simultaneous quantification of resveratrol levels in mouse plasma and brain and its application to pharmacokinetic and brain distribution studies.

    PubMed

    Ramalingam, Prakash; Ko, Young Tag

    2016-02-01

    A rapid, selective, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determine resveratrol levels in plasma and brain tissue in mice for supporting pharmacokinetic and brain distribution studies. Analytes were separated using a Sepax BR-C18 analytical column (5μm, 120Å, 1.0×100mm) and eluted using an isocratic elution mobile phase acetonitrile and 0.01% formic acid [60:40, v/v] at a flow rate of 0.1mL/min. Precursor and product ion transitions for analyte resveratrol m/z 226.9>184.8 and curcumin m/z 367.1>148.9 were monitored using triple quadrupole mass spectrometer with multiple reaction monitoring (MRM) in negative ionization mode. The method was validated with respect to accuracy, within- and between-day precision, linearity, limit of quantification, recovery, and matrix effects of analyte. The inter- and intra-day accuracy and precision were within the range of the US Food and Drug Administration (FDA) acceptance criteria, for both matrices. The method was also successfully applied to pharmacokinetic and brain distribution studies of resveratrol after intravenous administration of free resveratrol and resveratrol-loaded solid lipid nanoparticles to mice. The combined use of serial blood sampling, small sample volume, simple extraction, and capillary depletion method drastically improved resveratrol analysis from biological matrices.

  4. Simultaneous determination of carisoprodol and aspirin in human plasma using liquid chromatography-tandem mass spectrometry in polarity switch mode: application to a human pharmacokinetic study.

    PubMed

    Sreenivasulu, Vudagandla; Ramesh, Mullangi; Kumar, Inamadugu Jaswanth; Babu, Ravi Vasu; Pilli, Nageswara Rao; Krishnaiah, Abburi

    2013-02-01

    A simple, sensitive and rapid LC-MS/MS-ESI method has been developed and validated for simultaneous quantification of the carisoprodol and aspirin in human plasma. Carisoprodol was detected in positive ion mode, whereas aspirin was detected in negative ion mode. Carbamazepine and furosemide were used as internal standards (IS) for quantification of carisoprodol and aspirin, respectively. The extraction procedure involves a liquid-liquid extraction method with ter-butyl methyl ether. Chromatographic separation was achieved on a Zorbax XDB-Phenyl (4.6 × 75 mm, 3.5 µm) column using an isocratic mobile phase (5 mm ammonium acetate:methanol, 20:80, v/v) at a flow rate of 0.8 mL/min with a total run time of 2.2 min. A detailed method validation was performed as per the FDA guidelines. The standard curves found to be linear in the range of 25.5-4900 and 15.3-3000 ng/mL for carisoprodol and aspirin, respectively. The results met the acceptance criteria. Carisoprodol and aspirin were found to be stable in various stability studies. The validated method was successfully applied to a pharmacokinetic study following co-administration of carisoprodol (250 mg) and aspirin (75 mg) tablets by oral route to human volunteers. PMID:22674769

  5. Development of an LC/MS/MS method in order to determine arctigenin in rat plasma: its application to a pharmacokinetic study.

    PubMed

    Zou, Quanfei; Gu, Yuan; Lu, Rong; Zhang, Tiejun; Zhao, Guang-Rong; Liu, Changxiao; Si, Duanyun

    2013-09-01

    In this study, a simple and sensitive LC/MS/MS method was developed and validated for the determination of arctigenin in rat plasma. The MS detection was performed using multiple reaction monitoring at the transitions of m/z 373.2 → 137.3 for arctigenin and m/z 187.1 → 131.0 for psoralen (internal standard) with a Turbo IonSpray electrospray in positive mode. The calibration curves fitted a good linear relationship over the concentration range of 0.2-500 ng/mL. It was found that arctigenin is not stable enough at both room temperature and -80 °C unless mixed with methanol before storage. The validated LC/MS/MS method was successfully applied for the pharmacokinetic study of arctigenin in rats. After intravenous injection of 0.3 mg/kg arctigenin injection to rats, the maximum concentration, half-life and area under the concentration-time curve were 323 ± 65.2 ng/mL, 0.830 ± 0.166 and 81.0 ± 22.1 h ng/mL, respectively.

  6. Comparison of LC-UV and LC-MS methods for simultaneous determination of teriflunomide, dimethyl fumarate and fampridine in human plasma: application to rat pharmacokinetic study.

    PubMed

    Suneetha, A; Raja, Rajeswari K

    2016-09-01

    This study describes a comparison between LC-UV and LC-MS method for the simultaneous analyses of a few disease-modifying agents of multiple sclerosis. Quantitative determination of fampridine (FAM), teriflunomide (TFM) and dimethyl fumarate (DMF) was performed in human plasma with the recovery values in the range of 85-115%. A reversed-phase high-performance liquid chromatography (HPLC) with UV as well as MS detection is used. The method utilizes an XBridge C18 silica column and a gradient elution with mobile phase consisting of ammonium formate and acetonitrile at a flow rate of 0.5 mL min(-1) . The method adequately resolves FAM, TFM and DMF within a run time of 15 min. Owing to low molecular weights, the estimation of DMF and FAM is more versatile in UV than MS detection. With LC-UV, the detection limits of FAM, TFM and DMF were 0.1, 0.05, 0.05 μg and the quantification limit for all the analytes was 1 μg. With LC-MS, the detection and quantification limits for all of the analytes were 1 and 5 ng, respectively. The two techniques were completely validated and shown to be reproducible and sensitive. They were applied to a pharmacokinetic study in rats by a single oral dose. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26849839

  7. A sensitive liquid chromatographic-mass spectrometric method for simultaneous quantification of six iridoid glycosides from Zhi-zi-chi Decoction in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Qu, Kankan; Dai, Jinna; Zhao, Longshan; Lu, Yanan; Li, Bin; Zhao, Xu; Hou, Pengyi; Zhang, Yuanting; Bi, Kaishun; Chen, Xiaohui

    2013-05-01

    A sensitive liquid chromatographic-mass spectrometric (LC-MS) method was developed and validated for simultaneous determination of geniposide, geniposidic acid, scandoside methyl ester, gardenoside, deacetyl asperulosidic acid methyl ester and genipin-1-β-gentiobioside after oral administration of Zhi-zi-chi Decoction in rat plasma. The six iridoid glycosides were extracted from plasma samples by protein precipitation, and then separated on an Apollo C18 column (250 mm × 4.6mm, 5 μm) through the application of a gradient elution. The analytes were monitored in positive electrospray ionization by selected ion monitoring mode (SIM). The lower limits of quantitation (LLOQ) of the six analytes were all lower than 6 ng/mL. The accuracy (relative error, RE%) was between -7.0% and 9.9%, while the intra- and inter-day precisions (relative standard deviation, RSD%) were less than 6.3% and 9.8% for the six analytes, respectively. The developed method was successfully applied to a comparative pharmacokinetic study of the six iridoids in rat plasma after oral administration of Zhi-zi-chi Decoction and Gardenia jasminoides extract.

  8. Nevirapine quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry. Application to bioequivalence study.

    PubMed

    Laurito, Tiago L; Santagada, Vincenzo; Caliendo, Giuseppe; Oliveira, Celso H; Barrientos-Astigarraga, Rafael E; De Nucci, Gilberto

    2002-04-01

    A rapid, sensitive and specific method to quantify nevirapine in human plasma using dibenzepine as the internal standard (IS) was developed and validated. The method employed a liquid-liquid extraction. The analyte and the IS were chromatographed on a C(18) analytical column, (150 x 4.6 mm i.d. 4 microm) and analyzed by tandem mass spectrometry in the multiple reaction monitoring mode. The method had a chromatographic run time of 5.0 min and a linear calibration curve over the range 10-5000 ng ml(-1) (r(2) > 0.9970). The between-run precision, based on the relative standard deviation for replicate quality controls was 1.3% (30 ng ml(-1)), 2.8% (300 ng ml(-1)) and 3.6% (3000 ng ml(-1)). The between-run accuracy was 4.0, 7.0 and 6.2% for the above-mentioned concentrations, respectively. This method was employed in a bioequivalence study of two nevirapine tablet formulations (Nevirapina from Far-Manguinhos, Brazil, as a test formulation, and Viramune from Boehringer Ingelheim do Brasil Química e Farmacêutica, as a reference formulation) in 25 healthy volunteers of both sexes who received a single 200 mg dose of each formulation. The study was conducted using an open, randomized, two-period crossover design with a 3 week washout interval. The 90% confidence interval (CI) of the individual ratio geometric mean for Nevirapina/Viramune was 96.4-104.5% for AUC((0-last)), 91.4-105.1% for AUC((0-infinity)) and 95.3-111.6% for C(max) (AUC = area under the curve; C(max) = peak plasma concentration). Since both 90% CI for AUC((0-last)) and AUC((0-infinity)) and C(max) were included in the 80-125% interval proposed by the US Food and Drug Administration, Nevirapina was considered bioequivalent to Viramune according to both the rate and extent of absorption.

  9. Development and validation of a HPLC-MS/MS method for the determination of phytolaccagenin in rat plasma and application to a pharmacokinetic study.

    PubMed

    Wei, Fenghuan; Singh, Ravi Shankar Prasad; Fueth, Matthias; Swarts, Steven; Okunieff, Paul; Derendorf, Hartmut

    2015-03-25

    Radix Phytolaccae (the dried root of Phytolacca acinosa Roxb. or Phytolacca americana L.) is widely used in East Asian countries for the treatment of inflammation-related diseases. The active component of Radix Phtolaccae is Phytolcaccagenin a triterpenoid saponin. Phytolcaccagenin has anti-inflammatory activities that exceed those of Esculentoside A and its derivatives regarding suppression of LPS-induced inflammation, and has a lower toxicity profile with less hemolysis. To date, no information is available about analytical method and pharmacokinetic studies of phytolaccagenin. To explore PK profile of this compound, a HPLC-MS/MS assay of phytolaccagenin in rat plasma was developed and validated. The method was fully validated according to FDA Guidance for industry. The detection was performed by a triple-quadrupole tandem mass spectrometer with multiple reactions monitoring (MRM) in positive ion mode via electrospray ionization. The monitored transitions were m/z 533.2>515.3 for Phytolcaccagenin, and 491.2>473.2 for I.S. The analysis was performed on a Symmetry C18 column (4.6 mm × 50 mm, 3.5 μm) using gradient elution with the mobile phase consisting of acetonitrile and 0.1% formic acid water at a flow rate of 1 ml/min with a 1:1 splitter ratio. The method was validated with a LLOQ of 20 ng/ml and an ULOQ of 1000 ng/ml. The response versus concentration data were fitted with 1/x weighting and the correlation coefficient (r) were greater than 0.999. The average matrix effect and the average extraction recovery were acceptable. This validation in rat plasma demonstrated that phytolaccagenin was stable for 30 days when stored below -20°C, for 6h at room temperature (RT, 22°C), for 12 h at RT for prepared control samples in auto-sampler vials, and during three successive freeze/thaw cycles results at -20°C. The validated method has been successfully applied to an intravenous bolus pharmacokinetic study of phytolaccagenin in male Sprague-Dawley rats (10 mg

  10. Simultaneous determination of four bioactive flavonoids from Polygonum orientale L. in dog plasma by UPLC-ESI-MS/MS and application of the technique to pharmacokinetic studies.

    PubMed

    Huang, Yong; Zhang, Peng; He, Feng; Zheng, Lin; Wang, Yong-lin; Wu, Ji-zhou

    2014-04-15

    The in vivo effects of traditional herbal medicines are generally mediated by multiple bioactive components. The main constituents of Polygonum orientale L. are flavonoids such as orientin, vitexin, cynaroside, and quercitrin. The aim of this study was to develop and validate a method for characterizing these flavonoids, in order to better understand the pharmacokinetics and pharmacodynamics of P. orientale L. We used ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) to analyze the flavonoids. After precipitation of the proteins with methanol, the flavonoids were separated on a BEH C18 column (50mm×2.1mm, i.d., 1.7μm) by using an elution gradient of acetonitrile. Flavonoid content was determined using the multiple reaction monitoring (MRM) mode at m/z 449.2→329.2 for orientin, m/z 433.2→313.0 for vitexin, m/z 449.2→287.1 for cynaroside, m/z 449.2→303.4 for quercitrin, and m/z 417.0→267.0 for the internal standard, puerarin. Pharmacokinetics was assessed after intravenous administration of P. orientale L. extracts (POE) in Beagle dogs at a dose of 22, 44, or 88mg/kg. Analysis of the standard curves by linear regression revealed high linearity over a 243-fold dynamic range for the four flavonoids (the lower limit of quantitation values were 4-21ng/mL). The relative standard deviations of intra- and inter-day measurements were less than 15.1%, and the method was accurate to within -8.7% to 7.2%; the extraction recoveries from dog plasma were 70.6-89.3%, 69.8-88.7%, 72.5-85.7%, and 71.0-79.1% for orientin, vitexin, cynaroside, and quercitrin, respectively. Our results suggest non-linear pharmacokinetic characteristics with rapid clearance of the flavonoids. In conclusion, UPLC-ESI-MS/MS is a rapid and sensitive method for simultaneous quantification of multiple flavonoids from POE in dog plasma and is suitable for pharmacokinetic studies of herbal medicines. PMID:24662144

  11. The plasma focus as a tool for plasma-wall-interaction studies

    NASA Astrophysics Data System (ADS)

    Ramos, G.; Martinez, M.; Herrera, J. J. E.; Castillo, F.

    2015-03-01

    The study of the interaction of magnetized plasmas with candidate materials for fusion reactors, as for example tungsten, is a main topic in fusion research. Many studies simulate the plasma wall interaction using ion beams, while only a few use plasma simulators. Plasma foci can produce dense magnetized plasmas of deuterium and helium among other species. We used the plasma focus Fuego-Nuevo II, to expose tungsten samples to deuterium and helium plasmas. The samples were analysed by means of SEM, RBS and NRA, evidencing surface erosion, surface melting and retention of deuterium in a shallow surface layer of 250 nm amounting 6.5·1016 D/cm2. The plasma temperature has been measured at the position of the samples using a triple Langmuir probe and compared to calculations of a snowplow model. The modelling of the electrode to reach desired plasma parameters is discussed.

  12. Vacuum plasma spray applications on liquid fuel rocket engines

    NASA Astrophysics Data System (ADS)

    McKechnie, T. N.; Zimmerman, F. R.; Bryant, M. A.

    1992-07-01

    The vacuum plasma spray process (VPS) has been developed by NASA and Rocketdyne for a variety of applications on liquid fuel rocket engines, including the Space Shuttle Main Engine. These applications encompass thermal barrier coatings which are thermal shock resistant for turbopump blades and nozzles; bond coatings for cryogenic titanium components; wear resistant coatings and materials; high conductivity copper, NaRloy-Z, combustion chamber liners, and structural nickel base material, Inconel 718, for nozzle and combustion chamber support jackets.

  13. Spectroscopic studies of microwave plasmas containing hexamethyldisiloxane

    NASA Astrophysics Data System (ADS)

    Nave, A. S. C.; Mitschker, F.; Awakowicz, P.; Röpcke, J.

    2016-10-01

    Low-pressure microwave discharges containing hexamethyldisiloxane (HMDSO) with admixtures of oxygen and nitrogen, used for the deposition of silicon containing films, have been studied spectroscopically. Optical emission spectroscopy (OES) in the visible spectral range has been combined with infrared laser absorption spectroscopy (IRLAS). The experiments were carried out in order to analyze the dependence of plasma chemical phenomena on power and gas mixture at relatively low pressures, up to 50 Pa, and power values, up to 2 kW. The evolution of the concentration of the methyl radical, CH3, and of seven stable molecules, HMDSO, CH4, C2H2, C2H4, C2H6, CO and CO2, was monitored in the plasma processes by in situ IRLAS using tunable lead salt diode lasers (TDL) and external-cavity quantum cascade lasers (EC-QCL) as radiation sources. To achieve reliable values for the gas temperature inside and outside the plasma bulk as well as for the temperature in the plasma hot and colder zones, which are of great importance for calculation of species concentrations, three different methods based on emission and absorption spectroscopy data of N2, CH3 and CO have been used. In this approach line profile analysis has been combined with spectral simulation methods. The concentrations of the various species, which were found to be in the range between 1011 to 1015 cm-3, are in the focus of interest. The influence of the discharge parameters power, pressure and gas mixture on the molecular concentrations has been studied. To achieve further insight into general plasma chemical aspects the dissociation of the HMDSO precursor gas including its fragmentation and conversion to the reaction products was analyzed in detail.

  14. Depleted uranium plasma reduction system study

    SciTech Connect

    Rekemeyer, P.; Feizollahi, F.; Quapp, W.J.; Brown, B.W.

    1994-12-01

    A system life-cycle cost study was conducted of a preliminary design concept for a plasma reduction process for converting depleted uranium to uranium metal and anhydrous HF. The plasma-based process is expected to offer significant economic and environmental advantages over present technology. Depleted Uranium is currently stored in the form of solid UF{sub 6}, of which approximately 575,000 metric tons is stored at three locations in the U.S. The proposed system is preconceptual in nature, but includes all necessary processing equipment and facilities to perform the process. The study has identified total processing cost of approximately $3.00/kg of UF{sub 6} processed. Based on the results of this study, the development of a laboratory-scale system (1 kg/h throughput of UF6) is warranted. Further scaling of the process to pilot scale will be determined after laboratory testing is complete.

  15. Simultaneous determination of codeine, ephedrine, guaiphenesin and chlorpheniramine in beagle dog plasma using high performance liquid chromatography coupled with tandem mass spectrometric detection: application to a bioequivalence study.

    PubMed

    Hu, Ziyan; Zou, Qiaogen; Tian, Jixin; Sun, Lili; Zhang, Zunjian

    2011-12-15

    A rapid and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of codeine, ephedrine, guaiphenesin and chlorpheniramine in beagle dog plasma has been developed and validated. Following liquid-liquid extraction, the analytes were separated on a reversed-phase C(18) column (150 mm × 2.0 mm, 3 μm) using formic acid:10 mM ammonium acetate:methanol (0.2:62:38, v/v/v) as mobile phase at a flow rate of 0.2 mL/min and analyzed by a triple-quadrupole mass spectrometer in the selected reaction monitoring (SRM) mode. The method was linear for all analytes over the following concentration (ng/mL) ranges: codeine 0.08-16; ephedrine 0.8-160; guaiphenesin 80-16,000; chlorpheniramine 0.2-40. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. It is the first time that the validated HPLC-MS/MS method was successfully applied to a bioequivalence study in 6 healthy beagle dogs. PMID:22119507

  16. Determination of bevantolol in human plasma using liquid chromatography-electrospray ionization tandem mass spectrometry and its application to a bioequivalence study.

    PubMed

    Ren, Li; Wang, Zheng; Lou, Yiceng; Zheng, Lu; Zheng, Heng; Yin, Chunping

    2014-05-15

    A liquid chromatography-electrospray ionization tandem mass spectrometry method was established and validated for the determination of bevantolol in human plasma using propranolol as the internal standard. The optimal chromatographic behavior of bevantolol and propranolol was achieved on a Welch Ultimate XB-C18 column (5 μm, 150 mm × 2.1mm, Maryland, USA) with a mobile phase of acetonitrile-water (40:60, v/v) containing 10mM ammonium acetate and 0.1% formic acid. The mass spectrometer was operated in selected reaction monitoring mode using the transition m/z 346.1>165.1 for bevantolol and m/z 260.3>116.1 for propranolol. Sample preparation was carried out through protein precipitation with acetonitrile. The calibration curves were linear over the range of 5.00-1,000 ng/ml. The intra- and inter-day precisions were less than 6.7% and 6.6%, respectively. This method was successfully applied to the bioequivalence study of two kinds of bevantolol hydrochloride tablets in 24 Chinese male volunteers in fasting and postprandial experiment.

  17. Validated LC-MS/MS method for the simultaneous determination of hyperoside and 2''-O-galloylhyperin in rat plasma: application to a pharmacokinetic study in rats.

    PubMed

    Zhou, Donghui; Jin, Yuanzhe; Yao, Fengchen; Duan, Zhiying; Wang, Qi; Liu, Jing

    2014-08-01

    An LC-MS/MS method was developed for the first time to simultaneously determine hyperoside and 2''-O-galloylhyperin, two major components in Pyrola calliantha extract, in rat plasma. Following extraction by one-step protein precipitation with methanol, the analytes were separated on a Venusil MP-C18 column within 2 min, using methanol-water-formic acid (50:50:0.1, v/v/v) as the mobile phase at a flow rate of 0.4 mL/min. Detection was performed on electrospray negative ionization mass spectrometry by multiple-reaction monitoring of the transitions of 2''-O-galloylhyperin at m/z 615.1 → 301.0, of hyperoside at m/z 463.1 → 300.1, and of internal standard at m/z 415.1 → 295.1. The limits of quantification were 2 ng/mL for both hyperoside and 2''-O-galloylhyperin. The precisions were <13.1%, and the accuracies were between -9.1 and 5.5% for both compounds. The method was successfully applied in pharmacokinetic studies following intravenous administration of the total flavonoids of P. calliantha extract in rats.

  18. Development of a sensitive UPLC-ESI-MS/MS method for quantification of sofosbuvir and its metabolite, GS-331007, in human plasma: Application to a bioequivalence study.

    PubMed

    Rezk, Mamdouh R; Basalious, Emad B; Karim, Iman A

    2015-10-10

    A rapid and simple LC-MS/MS method was developed and validated for the simultaneous estimation of sofosbuvir (SF) and its metabolite GS-331007 (GS) using famotidine as an internal standard (IS). The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Extraction with ethyl acetate was used in sample preparation. The prepared samples were chromatographed on Acquity UPLC HSS C₁₈ (50 mm × 2.1 mm, 1.8 μm) column by pumping 0.1% formic acid and acetonitrile (50:50, v/v) in an isocratic mode at a flow rate of 0.3 ml/min. Method validation was performed as per the FDA guidelines and the standard curves were found to be linear in the range of 10-2500 ng/ml for both SF and its metabolite. The intra-day and inter-day precision and accuracy results were within the acceptable limits. A very short run time of 1.2 min made it possible to analyze more than 300 human plasma samples per day. The developed assay method was successfully applied to a bioequivalence study in human volunteers.

  19. Determination of lansoprazole enantiomers in dog plasma by column-switching liquid chromatography with tandem mass spectrometry and its application to a preclinical pharmacokinetic study.

    PubMed

    Wang, Hao; Sun, Yantong; Meng, Xiangjun; Yang, Bo; Wang, Jian; Yang, Yan; Gu, Jingkai

    2015-09-01

    Lansoprazole, a selective proton pump inhibitor, has a chiral benzimidazole sulfoxide structure and is used for the treatment of gastric acid hypersecretory related diseases. To investigate its stereoselective pharmacokinetics, a column-switching liquid chromatography with tandem mass spectrometry method was developed for the determination of lansoprazole enantiomers in dog plasma using (+)-pantoprazole as an internal standard. After a simple protein precipitation procedure with acetonitrile, matrix components left behind after sample preparation were further eliminated from the sample by reversed-phase chromatography on a C18 column. The fluent was fed to a chiral column for the separation of lansoprazole enantiomers. Baseline separation of lansoprazole enantiomers was achieved on a Chiralcel OZ-RH column using acetonitrile/0.1% formic acid in water (35:65, v/v) as the mobile phase at 40°C. The linearity of the calibration curves ranged from 3 to 800 ng/mL for each enantiomer. Intra- and inter-day precisions ranged from 2.1 to 7.3% with an accuracy of ±1.7% for (+)-lansoprazole, and from 1.6 to 6.9% with an accuracy of ±3.5% for (-)-lansoprazole, respectively. The validated method was successfully applied for the stereoselective pharmacokinetic study of lansoprazole in beagle dog after intravenous infusion.

  20. Simultaneous determination of codeine, ephedrine, guaiphenesin and chlorpheniramine in beagle dog plasma using high performance liquid chromatography coupled with tandem mass spectrometric detection: application to a bioequivalence study.

    PubMed

    Hu, Ziyan; Zou, Qiaogen; Tian, Jixin; Sun, Lili; Zhang, Zunjian

    2011-12-15

    A rapid and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of codeine, ephedrine, guaiphenesin and chlorpheniramine in beagle dog plasma has been developed and validated. Following liquid-liquid extraction, the analytes were separated on a reversed-phase C(18) column (150 mm × 2.0 mm, 3 μm) using formic acid:10 mM ammonium acetate:methanol (0.2:62:38, v/v/v) as mobile phase at a flow rate of 0.2 mL/min and analyzed by a triple-quadrupole mass spectrometer in the selected reaction monitoring (SRM) mode. The method was linear for all analytes over the following concentration (ng/mL) ranges: codeine 0.08-16; ephedrine 0.8-160; guaiphenesin 80-16,000; chlorpheniramine 0.2-40. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. It is the first time that the validated HPLC-MS/MS method was successfully applied to a bioequivalence study in 6 healthy beagle dogs.

  1. Simultaneous LC-MS/MS determination of five tripterygium pyridine alkaloids in dog plasma and its application to their pharmacokinetic study after oral administration of tripterygium glycosides tablets.

    PubMed

    Su, Meng-xiang; Song, Min; Yang, Da-song; Shi, Jin-fang; Di, Bin; Hang, Tai-jun

    2015-05-15

    A sensitive and selective liquid chromatography tandem mass spectrometric method was developed and validated for the simultaneous determination of five pyridine alkaloids contained in tripterygium glycosides tablets (triptolide, wilforine, wilforgine, wilfording and wilfortrine) in dog plasma. The analysis was carried out on a Sepax GP-Phenyl column using a mixture of methanol and 10mmol/L ammonium formate buffer solution containing 0.1% formic acid (75:25, v/v) as the mobile phase pumped at a flow-rate of 1.0mL/min. All MS data were obtained in the positive ESI mode with selective multiple reaction monitoring of ion transitions. The method was fully validated to be accurate and precise with a linear range of 0.2-1000ng/mL for triptolide and 0.05-1000ng/mL for the other four pyridine alkaloids. The intra-day and inter-day precisions (relative standard deviation, RSD, %) were within 10.6% and 14.0%, respectively, and the relative error (RE, %) were all less than 13.1%. The method was successfully applied to multi-components pharmacokinetic study of the five pyridine alkaloids in beagle dogs after a single oral administration of 3mg/kg and 30mg/kg tripterygium glycosides tablets, respectively, and a multiple oral administration of 30mg/kg for 6 consecutive days. PMID:25855315

  2. Electron-beam generated plasmas for processing applications

    NASA Astrophysics Data System (ADS)

    Meger, Robert; Leonhardt, Darrin; Murphy, Donald; Walton, Scott; Blackwell, David; Fernsler, Richard; Lampe, Martin; Manheimer, Wallace

    2001-10-01

    NRL's Large Area Plasma Processing System (LAPPS) utilizes a 5-10 mA/cm^2, 2-4 kV, 1 cm x 30-60 cm cross section beam of electrons guided by a magnetic field to ionize a low density (10-100 mTorr) gas.[1] Beam ionization allows large area, high density, low temperature plasmas to be generated in an arbitrary gas mixture at a well defined location. Energy and composition of particle fluxes to surfaces on both sides of the plasma can be controlled by gas mixture, location, rf bias, and other factors. Experiments have been performed using both pulsed and cw beams. Extensive diagnostics (Langmuir probes, mass and ion energy analyzers, optical emissions, microwave interferometry, etc.) have been fielded to measure the plasma properties and neutral particle fluxes (ions, neutrals, free radicals) with and without rf bias on nearby surfaces both with the beam on and off. Uniform, cold (Te < 1eV), dense (ne 10^13 cm-3) plasmas in molecular and atomic gases and mixtures thereof have been produced in agreement with theoretical expectations. Initial tests of LAPPS application such as ashing, etching, sputtering, and diamond growth have been performed. Program status will be presented. [1]R.A. Meger, et al, Phys. of Plasmas 8(5), p. 2558 (2001)

  3. Laser production and heating of plasma for MHD application

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1988-01-01

    Experiments have been made on the production and heating of plasmas by the absorption of laser radiation. These experiments were performed to ascertain the feasibility of using laser-produced or laser-heated plasmas as the input for a magnetohydrodynamic (MHD) generator. Such a system would have a broad application as a laser-to-electricity energy converter for space power transmission. Experiments with a 100-J-pulsed CO2 laser were conducted to investigate the breakdown of argon gas by a high-intensity laser beam, the parameters (electron density and temperature) of the plasma produced, and the formation and propagation of laser-supported detonation (LSD) waves. Experiments were also carried out using a 1-J-pulsed CO2 laser to heat the plasma produced in a shock tube. The shock-tube hydrogen plasma reached electron densities of approximately 10 to the 17th/cu cm and electron temperatures of approximately 1 eV. Absorption of the CO2 laser beam by the plasma was measured, and up to approximately 100 percent absorption was observed. Measurements with a small MHD generator showed that the energy extraction efficiency could be very large with values up to 56 percent being measured.

  4. Determination of BmKCT-13, a chlorotoxin-like peptide, in rat plasma by LC-MS/MS: application to a preclinical pharmacokinetic study.

    PubMed

    Zang, Min; Liu, Xiaoqiang; Chen, Lin; Xiao, Qingqing; Yuan, Linwen; Yang, Jin

    2014-02-01

    A novel chlorotoxin-like toxin derived from Buthus martensii Karsch, namely BmKCT-13, is a potential candidate for glioma therapy and highly homologous to the chlorotoxin (CTX) derived from the venom of the scorpion Leiurus quinquestriatus. In this study, a simple, sensitive, and robust analytical method based on liquid chromatography-tandem mass spectrometry has been developed for the determination of BmKCT-13 in rat plasma using CTX as internal standard (IS). After sample preparation by protein precipitation with 0.1% formic acid in methanol, chromatography was performed on a Hanbon Dubhe C18 column (150 mm × 2.1 mm, 5 μm, and 100 Å) using a gradient elution with 0.1% formic acid in water and methanol. Mass spectrometry involved positive electrospray ionization and multiple reaction monitoring of the transitions at m/z 780.2→69.9 for BmKCT-13 and m/z 800.2→69.7 for CTX. The method was linear over the concentration range 10-1000 ng/mL with a lower limit of quantification of 10 ng/mL. Intra- and inter-day precision (expressed as relative standard deviation, RSD) were ≤8.1 and ≤7.9%, respectively, with intra-and inter-day accuracy of 94.5-99.0%. Recoveries of BmKCT-13 and IS were more than 65% and matrix effects were not significant. Stability studies showed that BmKCT-13 was stable under a variety of storage conditions. The method was successfully applied to a pharmacokinetic study involving intravenous administration of BmKCT-13 to rats.

  5. Plasma Passivation of Compound Semiconductors for Device Applications.

    NASA Astrophysics Data System (ADS)

    Herman, Jonathan Samuel

    Plasma processing such as PECVD can be used in a variety of ways for both film deposition and surface passivation to improve the performance of solid state devices in both the silicon and compound semiconductor areas. Film properties can be improved over the conventional constant temperature uninterrupted deposition method, and plasma pretreatment can be used to alter the semiconductor surface prior to film deposition. Novel deposition techniques consisting of interrupting the SiO_2 film deposition for in -situ plasma treatments have been developed to improve the electrical behavior of the plasma SiO_2 -Si interface. The most successful of these was the two-temperature method, where the interface was formed at lower temperature than the rest of the film. Low power hydrogen plasmas were used during the temperature ramp to simulate a conventional MOS post-metallization anneal and reduce the interface trap density. Hydrogen sulfide plasmas were used to passivate the surfaces of both GaAs and InP for subsequent dielectric deposition (SiO_2). Plasma processing provides a high degree of reproducibility compared to wet chemical processes through computer control of parameters such as chamber pressure, gas flows, temperature, rf power, and exposure time. The electrical and structural properties of the interfaces were characterized with C-V, XPS, SE and PL. The H_2S treatments were more robust than similar treatments involving nitrogen plasmas. The applicability of these passivation techniques was demonstrated by fabricating metal-insulator-semiconductor FET's on GaAs and InP substrates using a fully ion implaned planar process for both inversion and depletion mode transistors. The sulfide treated samples showed considerable improvement in performance over the control samples.

  6. Computational studies of plasma lipoprotein lipids.

    PubMed

    Pan, Lurong; Segrest, Jere P

    2016-10-01

    Plasma lipoproteins are macromolecular assemblies of proteins and lipids found in the blood. The lipid components of lipoproteins are amphipathic lipids such as phospholipids (PLs), and unesterified cholesterols (UCs) and hydrophobic lipids such as cholesteryl esters (CEs) and triglycerides (TGs). Since lipoproteins are soft matter supramolecular assemblies easily deformable by thermal fluctuations and they also exist in varying densities and protein/lipid components, a detailed understanding of their structure/function is experimentally difficult. Molecular dynamics (MD) simulation has emerged as a particularly promising way to explore the structure and dynamics of lipoproteins. The purpose of this review is to survey the current status of computational studies of the lipid components of the lipoproteins. Computational studies aim to explore three levels of complexity for the 3-dimensional structural dynamics of lipoproteins at various metabolic stages: (i) lipoprotein particles consist of protein with minimal lipid; (ii) lipoprotein particles consist of PL-rich discoidal bilayer-like lipid particles; (iii) mature circulating lipoprotein particles consist of CE-rich or TG-rich spheroidal lipid-droplet-like particles. Due to energy barriers involved in conversion between these species, other biomolecules also participate in lipoprotein biological assembly. For example: (i) lipid-poor apolipoprotein A-I (apoA-I) interacts with ATP-binding cassette transporter A1 (ABCA1) to produce nascent discoidal high density lipoprotein (dHDL) particles; (ii) lecithin-cholesterol acyltransferase (LCAT) mediates the conversion of UC to CE in dHDL, driving spheroidal HDL (sHDL) formation; (iii) transfer proteins, cholesterol ester transfer protein (CETP) and phospholipid transfer protein (PLTP), transfer both CE and TG and PL, respectively, between lipoprotein particles. Computational studies have the potential to explore different lipoprotein particles at each metabolic stage in

  7. Gas laser for efficient sustaining a continuous optical discharge plasma in scientific and technological applications

    SciTech Connect

    Zimakov, V P; Kuznetsov, V A; Kedrov, A Yu; Solov'ev, N G; Shemyakin, A N; Yakimov, M Yu

    2009-09-30

    A stable high-power laser is developed for the study and technical applications of a continuous optical discharge (COD). The laser based on the technology of a combined discharge in a scheme with a fast axial gas flow emits 2.2 kW at 10.6 {mu}m per meter of the active medium in continuous and repetitively pulsed regimes with the electrooptical efficiency 20%. The sustaining of the COD plasma in argon and air is demonstrated at the atmospheric pressure. The emission properties of the COD plasma are studied and its possible applications are discussed. (lasers)

  8. Current and Perspective Applications of Dense Plasma Focus Devices

    SciTech Connect

    Gribkov, V. A.

    2008-04-07

    Dense Plasma Focus (DPF) devices' applications, which are intended to support the main-stream large-scale nuclear fusion programs (NFP) from one side (both in fundamental problems of Dense Magnetized Plasma physics and in its engineering issues) as well as elaborated for an immediate use in a number of fields from the other one, are described. In the first direction such problems as self-generated magnetic fields, implosion stability of plasma shells having a high aspect ratio, etc. are important for the Inertial Confinement Fusion (ICF) programs (e.g. as NIF), whereas different problems of current disruption phenomenon, plasma turbulence, mechanisms of generation of fast particles and neutrons in magnetized plasmas are of great interest for the large devices of the Magnetic Plasma Confinement--MPC (e.g. as ITER). In a sphere of the engineering problems of NFP it is shown that in particular the radiation material sciences have DPF as a very efficient tool for radiation tests of prospect materials and for improvement of their characteristics. In the field of broad-band current applications some results obtained in the fields of radiation material sciences, radiobiology, nuclear medicine, express Neutron Activation Analysis (including a single-shot interrogation of hidden illegal objects), dynamic non-destructive quality control, X-Ray microlithography and micromachining, and micro-radiography are presented. As the examples of the potential future applications it is proposed to use DPF as a powerful high-flux neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration for innovative experiments in nuclear physics, for the goals of radiation treatment of malignant tumors, for neutron tests of materials of the first wall, blankets and NFP device's constructions (with fluences up to 1 dpa per a year term), and ns pulses of fast electrons, neutrons and hard X-Rays for brachytherapy.

  9. Current and Perspective Applications of Dense Plasma Focus Devices

    NASA Astrophysics Data System (ADS)

    Gribkov, V. A.

    2008-04-01

    Dense Plasma Focus (DPF) devices' applications, which are intended to support the main-stream large-scale nuclear fusion programs (NFP) from one side (both in fundamental problems of Dense Magnetized Plasma physics and in its engineering issues) as well as elaborated for an immediate use in a number of fields from the other one, are described. In the first direction such problems as self-generated magnetic fields, implosion stability of plasma shells having a high aspect ratio, etc. are important for the Inertial Confinement Fusion (ICF) programs (e.g. as NIF), whereas different problems of current disruption phenomenon, plasma turbulence, mechanisms of generation of fast particles and neutrons in magnetized plasmas are of great interest for the large devices of the Magnetic Plasma Confinement—MPC (e.g. as ITER). In a sphere of the engineering problems of NFP it is shown that in particular the radiation material sciences have DPF as a very efficient tool for radiation tests of prospect materials and for improvement of their characteristics. In the field of broad-band current applications some results obtained in the fields of radiation material sciences, radiobiology, nuclear medicine, express Neutron Activation Analysis (including a single-shot interrogation of hidden illegal objects), dynamic non-destructive quality control, X-Ray microlithography and micromachining, and micro-radiography are presented. As the examples of the potential future applications it is proposed to use DPF as a powerful high-flux neutron source to generate very powerful pulses of neutrons in the nanosecond (ns) range of its duration for innovative experiments in nuclear physics, for the goals of radiation treatment of malignant tumors, for neutron tests of materials of the first wall, blankets and NFP device's constructions (with fluences up to 1 dpa per a year term), and ns pulses of fast electrons, neutrons and hard X-Rays for brachytherapy.

  10. Application of particle image velocimetry to dusty plasma systems

    NASA Astrophysics Data System (ADS)

    Williams, Jeremiah D.

    2016-06-01

    > Particle image velocimetry is a fluid measurement technique that has been used for more than 20 years to characterize the particle transport and thermal state of dusty plasma systems. This manuscript provides an overview of this diagnostic technique, highlighting the strengths and limitations that are associated with its use. Additionally, the variations of this technique that have been applied in the study of dusty plasma systems will be discussed, along with a small selection of measurements that can be made with the technique. Potential future directions for this diagnostic tool within the dusty plasma community will also be discussed.

  11. Physics and applications of atmospheric non-thermal air plasma with reference to environment

    NASA Astrophysics Data System (ADS)

    Marode, E.; Djermoune, D.; Dessante, P.; Deniset, C.; Ségur, P.; Bastien, F.; Bourdon, A.; Laux, C.

    2009-12-01

    Since air is a natural part of our environment, special attention is given to the study of plasmas in air at atmospheric pressure and their applications. This fact promoted the study of electrical conduction in air-like mixtures, i.e. mixtures containing an electronegative gas component. If the ionization growth is not limited its temporal evolution leads to spark formation, i.e. a thermal plasma of several thousand kelvins in a quasi-local thermodynamic equilibrium state. But before reaching such a thermal state, a plasma sets up where the electrons increase their energy characterized by an electron temperature Te much higher than that of heavy species T or T+ for the ions. Since the plasma is no longer characterized by only one temperature T, it is said to be in a non-thermal plasma (NTP) state. Practical ways are listed to prevent electron ionization from going beyond the NTP states. Much understanding of such NTP may be gathered from the study of the simple paradigmatic case of a discharge induced between a sharp positively stressed point electrode facing a grounded negative plane electrode. Some physical properties will be gathered from such configurations and links underlined between these properties and some associated applications, mostly environmental. Aerosol filtration and electrostatic precipitators, pollution control by removal of hazardous species contained in flue gas exhaust, sterilization applications for medical purposes and triggering fuel combustion in vehicle motors are among such applications nowadays.

  12. Simultaneous Determination of L-tetrahydropalmatine and Cocaine in Human Plasma by Simple UPLC-FLD Method: Application in Clinical Studies

    PubMed Central

    Yu, Mingming; Hassan, Hazem E.; Ibrahim, Ahmed; Bauer, Kenneth S.; Kelly, Deanna L.; Wang, Jia Bei

    2014-01-01

    Currently, there are no FDA approved medications for treatment of cocaine addiction underscoring the dire need to develop such a product. There is an accumulating body of evidence that L-tetrahydropalmatine (L-THP), a non-selective dopamine antagonist, can be used for the treatment of cocaine addiction. Indeed, the FDA recently approved its usage in a Phase I study in cocaine abusers and it was indispensable to develop a simple and sensitive method for the simultaneous determination of L-THP and cocaine in human plasma. We developed a UPLC-FLD method for quantitation of these molecules using an ACQUITY BEH C18 column (2.1 × 50mm, 1.7um) and a mobile phase that consisted of 5 mM ammonium phosphate (PH=4.75), methanol, and acetonitrile (v:v:v, 78:16:6). Venlafaxine was used as the internal standard while hexane was used for the liquid-liquid extraction. The flow rate was 0.4ml/min with fluorescence detection using an excitation wavelength of 230nm and emission detection wavelength of 315nm. This method was selective, linear and sensitive with a lower limit of quantification of 2.5 ng/mL for both cocaine and L-THP. The intra-day precision of cocaine and L-THP was <9.50% while the accuracy was <4.29%. The inter-day precision of cocaine and L-THP was <9.14%, and the accuracy was <12.49%. The recovery for cocaine and L-THP ranged from (43.95 - 50.02%) and (54.65 - 58.31%), respectively. In comparison to forty reported cocaine quantitation methods this method is simple, sensitive and cost-effective and can be used for simultaneous quantitation of L-THP and cocaine. This method meets the FDA guidelines and can be used in current and future clinical studies. PMID:24996068

  13. Determination of 21-hydroxydeflazacort in human plasma by high-performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry. Application to bioequivalence study.

    PubMed

    Ifa, D R; Moraes, M E; Moraes, M O; Santagada, V; Caliendo, G; de Nucci, G

    2000-03-01

    A liquid chromatographic atmospheric pressure chemical ionization tandem mass spectrometric method is described for the determination of 21-hydroxydeflazacort in human plasma using dexamethasone 21-acetate as an internal standard. The procedure requires a single diethyl ether extraction. After evaporation of the solvent under a nitrogen flow, the analytes are reconstituted in the mobile phase, chromatographed on a C18 reversed-phase column and analyzed by mass spectrometry via a heated nebulizer interface where they are detected by multiple reaction monitoring. The method has a chromatographic run time of less than 5 min and a linear calibration curve with a range of 1-400 ng ml(-1) (r>0.999). The between-run precision, based on the relative standard deviation for replicate quality controls, was < or =5.5% (10 ng ml(-1)), 1.0% (50 ng ml(-1)) and 2.7% (200 ng ml(-1)). The between-run accuracy was +/-7.1, 3.8 and 4.8% for the above concentrations, respectively. This method was employed in a bioequivalence study of two DFZ tablet formulations (Denacen from Marjan Industria e Comercio, Brazil, as a test formulation, and Calcort from Merrell Lepetit, Brazil, as a reference formulation) in 24 healthy volunteers of both sexes who received a single 30 mg dose of each formulation. The study was conducted using an open, randomized, two-period crossover design with a 7-day washout interval. The 90% confidence interval (CI) of the individual geometric mean ratio for Denacen/Calcort was 89.8-109.5% for area under the curve AUC(0-24 h) and 80.7-98.5% for Cmax. Since both the 90% CI for AUC(0-24 h) and Cmax were included in the 80-125% interval proposed by the US Food and Drug Administration, Denacen was considered bioequivalent to Calcort according to both the rate and extent of absorption.

  14. Method Development and Validation of Liquid Chromatography-Tandem Mass Spectrometry for Angiotensin-II in Human Plasma: Application to Study Interaction Between Atorvastatin & Olmesartan Drug Combination.

    PubMed

    Das, Rakesh; Pal, Tapan Kumar

    2015-07-01

    Simple and sensitive Liquid Chromatography-Tandem Mass Spectrometry (LCMS/MS) method was developed and validated, then was implicated on hypertensive human subjects to study drug interaction of atorvastatin (ATVS) and Olmesartan (OLM) on status of Angiotensin-II (ANG-II). The ANG-II in plasma was extracted with 5 mL methanol containing 5 % formic acid through C18 (cartridges) liquid-liquid extraction, dried and reconstituted with 1 mL of 16 % acetonitrile in 0.1 % formic acid in water. The chromatographic separation of ANG-II with a Agilent technology 6410 Triple quadrupole was carried multiple reaction monitoring scan mode with a Agilent 1290 Infinity LC system for UHPLC. The sample were separated on a (Thermo Scientific) Hy-Purity advance (50 × 4.6 mm, 5 μm) using Mobile Phase A: 16 % acetonitrile in 0.1 % formic acid in water and Mobile Phase B: 0.1 % formic acid in methanol at a flow rate of 0.3 mL/min, performed at ambient temperature. The mobile phase gradient of 16 % acetonitrile in water was linearly increased to 38 % acetonitrile over 10 min and subsequently the mobile-phase was increased to 100 % acetonitrile over 15 min. The developed method was validated for specificity, accuracy, precision, stability, linearity, sensitivity and recovery. The method was linear between peak area ratio of standard and internal standard over the range of 50-800 ng/mL. The method was successfully applied for the drug interaction study revealed levels of ANG-II were significantly higher in ATVS + OLM treatment condition as compared to individual treatment of OLM. This reflects the reason of low effectiveness of ATVS + OLM in combination instead of synergistic activity.

  15. Determination of 21-hydroxydeflazacort in human plasma by high-performance liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry. Application to bioequivalence study.

    PubMed

    Ifa, D R; Moraes, M E; Moraes, M O; Santagada, V; Caliendo, G; de Nucci, G

    2000-03-01

    A liquid chromatographic atmospheric pressure chemical ionization tandem mass spectrometric method is described for the determination of 21-hydroxydeflazacort in human plasma using dexamethasone 21-acetate as an internal standard. The procedure requires a single diethyl ether extraction. After evaporation of the solvent under a nitrogen flow, the analytes are reconstituted in the mobile phase, chromatographed on a C18 reversed-phase column and analyzed by mass spectrometry via a heated nebulizer interface where they are detected by multiple reaction monitoring. The method has a chromatographic run time of less than 5 min and a linear calibration curve with a range of 1-400 ng ml(-1) (r>0.999). The between-run precision, based on the relative standard deviation for replicate quality controls, was < or =5.5% (10 ng ml(-1)), 1.0% (50 ng ml(-1)) and 2.7% (200 ng ml(-1)). The between-run accuracy was +/-7.1, 3.8 and 4.8% for the above concentrations, respectively. This method was employed in a bioequivalence study of two DFZ tablet formulations (Denacen from Marjan Industria e Comercio, Brazil, as a test formulation, and Calcort from Merrell Lepetit, Brazil, as a reference formulation) in 24 healthy volunteers of both sexes who received a single 30 mg dose of each formulation. The study was conducted using an open, randomized, two-period crossover design with a 7-day washout interval. The 90% confidence interval (CI) of the individual geometric mean ratio for Denacen/Calcort was 89.8-109.5% for area under the curve AUC(0-24 h) and 80.7-98.5% for Cmax. Since both the 90% CI for AUC(0-24 h) and Cmax were included in the 80-125% interval proposed by the US Food and Drug Administration, Denacen was considered bioequivalent to Calcort according to both the rate and extent of absorption. PMID:10767775

  16. Simple and rapid determination of zafirlukast in plasma by ultra-performance liquid chromatography tandem mass spectrometric method: application into pharmacokinetic study in rabbits.

    PubMed

    Iqbal, M; Ezzeldin, E; Al-Rashood, K A; Al-Khamees, K I; Khan, R M A; Raish, M; Anwer, T

    2014-08-01

    Zafirlukast is a selective leukotriene receptor antagonist used for the prophylaxis and chronic treatment of asthma. The aim of the present study was to develop a simple sensitive ultra-performance liquid chromatography tandem mass spectroscopy method for rapid determination of zafirlukast in plasma. After a simple one step protein precipitation by acetonitrile, zafirlukast and montelukast (IS) were separated on Acquity UPLC BEH(TM) C18 column (50 × 2.1 mm, i.d. 1.7 µm, Waters, USA) using a mobile phase of acetonitrile:water containing 10 mM acetic acid (80:20, v/v) at a flow rate of 0.3 mL/min. Zafirlukast and IS were eluted at 0.51 and 1.1 min, respectively with a total run time of only 1.5 min. The mass spectrometric determination was carried out using an electrospray interface operated in the negative mode with multiple reactions monitoring mode. The precursor to product ion transitions of m/z 574.11>462.07 and m/z 584.2>472.1 were used to quantify zafirlukast and IS, respectively. The method was linear in the concentration range of 0.17-600 ng/mL with coefficients of determination greater than 0.996 and lower limit of quantitation of 0.17 ng/mL. Intra-day and inter-day accuracies were 88.3-113.9% and the precisions were ≤ 12.6%. Zafirlukast was found to stable under various storage and sample processing conditions as per guidelines of bio-analytical method validation. The method developed herein is simple and rapid, and was successfully applied for the pharmacokinetic study in rabbits.

  17. Reversed-phase high-performance liquid chromatographic determination of enoxacin and 4-oxo-enoxacin in human plasma and prostatic tissue. Application to a pharmacokinetic study.

    PubMed

    Hamel, B; Audran, M; Costa, P; Bressolle, F

    1998-07-01

    A simple high-performance liquid chromatographic method has been developed for the simultaneous determination of enoxacin and 4-oxo-enoxacin in plasma and prostatic tissue. The work-up procedure involves a liquid-liquid extraction step followed by isocratic chromatography on a reversed-phase analytical column, with ultraviolet absorbance detection (lambda = 340 nm). Using a mobile phase of 20.9% (v/v) acetonitrile buffer (pH 2.1), adequate retention time and separation among the analytes has been obtained using tetrabutylammonium hydroxide included in the eluent. Retention times are 5.2 min for enoxacin, 6.8 min for pefloxacin and 12 min for 4-oxo-enoxacin. For plasma and prostatic tissue, the precision of the assay was below 9%. The percent recovery from the nominal values for accuracy ranged from 94 to 108%. The limits of quantitation were 20 ng/ml for plasma and 50 ng/g for tissue (precision < 18%). The detection limits were 10 ng/ml and 25 ng/g, respectively. The calibration curves were linear from 20 to 1000 ng/ml for plasma and from 50 to 2500 ng/g for tissue. In plasma, the extraction recoveries averaged 52% for enoxacin and 63% for 4-oxo-enoxacin. In prostatic tissue, they were 57 and 76% for the two analytes, respectively. This method has been employed for the determination of enoxacin and 4-oxo-enoxacin in plasma and prostatic tissue samples from patients following repeated oral administration of enoxacin (400 mg twice a day for four days).

  18. Characterization of the axial plasma shock in a table top plasma focus after the pinch and its possible application to testing materials for fusion reactors

    SciTech Connect

    Soto, Leopoldo Pavez, Cristian; Moreno, José; Inestrosa-Izurieta, María José; Veloso, Felipe; Gutiérrez, Gonzalo; Vergara, Julio; Clausse, Alejandro; Bruzzone, Horacio; Castillo, Fermín; and others

    2014-12-15

    The characterization of plasma bursts produced after the pinch phase in a plasma focus of hundreds of joules, using pulsed optical refractive techniques, is presented. A pulsed Nd-YAG laser at 532 nm and 8 ns FWHM pulse duration was used to obtain Schlieren images at different times of the plasma dynamics. The energy, interaction time with a target, and power flux of the plasma burst were assessed, providing useful information for the application of plasma focus devices for studying the effects of fusion-relevant pulses on material targets. In particular, it was found that damage factors on targets of the order of 10{sup 4} (W/cm{sup 2})s{sup 1/2} can be obtained with a small plasma focus operating at hundred joules.

  19. LC-MS/MS method for the simultaneous determination of PA-824, moxifloxacin and pyrazinamide in rat plasma and its application to pharmacokinetic study.

    PubMed

    Wang, Libin; Xu, Yue; Liang, Li; Diao, Chunyan; Liu, Xueying; Zhang, Jianchun; Zhang, Shengyong

    2014-08-01

    A simple, sensitive and rapid LC-MS/MS method has been developed and validated for simultaneous determination of PA-824, moxifloxacin, and pyrazinamide in rat plasma using metronidazole as internal standard. Sample preparation involved a simple one-step protein precipitation with methanol, followed by centrifugation and evaporation of the organic solvent. The residue was redissolved in mobile phase and analyzed by LC-MS/MS. An Inertsil(®) ODS3 C18 column (150mm×4.6mm, 5μm), a mobile phase composed of methanol-0.03% TEA (triethylamine) in water (85:15, v/v), and a flow rate of 0.5mL/min were employed, and the total run time was 6.0min. The mass spectrometer was run in positive ion ESI-APCI combined mode using multiple reaction monitoring (MRM) to monitor the mass transitions. The method was validated for accuracy, precision, linearity, range, selectivity, lower limit of quantification (LLOQ), recovery, and matrix effect. All validation parameters met the acceptance criteria according to regulatory guidelines. The LLOQ was 1.0μg/mL for pyrazinamide and 0.1μg/mL for PA-824 and moxifloxacin. The recoveries obtained for PA-824, moxifloxacin and pyrazinamide were ≥85%. Intra-day and inter-day coefficients of variation were less than 10%. The method had been successfully applied to a pharmacokinetic study of fixed dose administration of PA-824, moxifloxacin, pyrazinamide and their combination in SD rat. Significant differences of Tmax, Cmax, AUC(0-t) and CLz/F were observed between the single and combined groups after equal dose of PA-824 and moxifloxacin administration, which revealed the possibility of drug-drug interaction (DDI) between the PaMZ combination. PMID:24798753

  20. Simultaneous determination of cefdinir and cefixime in human plasma by RP-HPLC/UV detection method: Method development, optimization, validation, and its application to a pharmacokinetic study.

    PubMed

    Khan, Abbas; Iqbal, Zafar; Khan, Muhammad Imran; Javed, Khalid; Khan, Abad; Ahmad, Lateef; Shah, Yasar; Nasir, Fazli

    2011-08-15

    A novel isocratic reversed-phase high performance liquid-chromatography/ultraviolet detection method for simultaneous determination of cefdinir and cefixime in human plasma was developed and validated after optimization of various chromatographic conditions and other experimental parameters. Sample preparation based on a simple extraction procedure consisting of deproteination and extraction with 3 parts of 6% trichloroacetic acid aqueous solution followed by volume make up with the aqueous component of the mobile phase obtained best recoveries of the two analytes. Samples were separated on a Supelco Discovery HS C(18) (150 mm × 4.6 mm, 5 μm) analytical column protected by a Perkin Elmer C(18) (30 mm × 4.6 mm, 10 μm) guard cartridge. The mobile phase, methanol/acetonitrile (50/50, v/v):0.05% trifluoroacetic acid (19:81, v/v), operated at 50°C column oven temperature was pumped at a flow rate of 2.0 mL min(-1) and the column eluents were monitored at a wavelength of 285 nm. When Sample was injected into the Perkin Elmer high performance liquid-chromatography system through Rheodyne manual (or auto-sampler) injector equipped with 20 μL loop, separation was achieved within 4 min. The present method demonstrated acceptable values for selectivity, linearity within the expected concentration range (0.004-5.0 μg mL(-1); r(2)>0.999 for both analytes), recovery (>95% for cefdinir and >96% for cefixime), precision (%RSD<2.0 for cefdinir and <2.2 for cefixime), sensitivity (limit of detection: 1 ng mL(-1) and lower limit of quantification: 4 ng mL(-1) for both analytes), stability of solutions, and robustness. The method was efficiently applied to a pharmacokinetic study in healthy volunteers.

  1. Simultaneous quantification of vortioxetine, carvedilol and its active metabolite 4-hydroxyphenyl carvedilol in rat plasma by UPLC-MS/MS: Application to their pharmacokinetic interaction study.

    PubMed

    Huang, Yi; Zheng, Shuangli; Pan, Yongyang; Li, Tao; Xu, Zhi-Sheng; Shao, Meng-Meng

    2016-09-01

    To establish a rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of vortioxetine, carvedilol and its metabolite 4-hydroxyphenyl carvedilol in rat plasma. The analytes and the internal standard (diazepam) were separated on an Acquity UPLC BEH C18 chromatography column (2.1mm×50mm, 1.7μm) using gradient elution with a mobile phase of acetonitrile and 0.1% formic acid in water at a flow rate of 0.4mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 299.2→150.1 for vortioxetine, m/z 407.2→100.3 for carvedilol, m/z 423.2→100.1 for 4-hydroxyphenyl carvedilol and m/z 285.2→193.1 for diazepam (IS) using a positive electrospray ionization interface. The method was validated over a concentration range of 0.5-100ng/mL for vortioxetine, 0.5-1000ng/mL for carvedilol and 0.1-50ng/mL for 4-hydroxyphenyl carvedilol. Total time for each chromatograph was 3.0min. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels exhibited relative standard deviations (RSD)<11.6% and the accuracy values ranged from -12.2% to 11.3%. The analytical method was successfully applied to a pharmacokinetic interaction study of vortioxetine and carvedilol after oral administration vortioxetine and carvedilol in rats. Results suggested that the co-administration of vortioxetine and carvedilol results in a significant drug interaction in rats. PMID:27262994

  2. Simultaneous determination of ledipasvir, sofosbuvir and its metabolite in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Pan, Chenwei; Chen, Yongping; Chen, Weilai; Zhou, Guangyao; Jin, Lingxiang; Zheng, Yi; Lin, Wei; Pan, Zhenzhen

    2016-01-01

    In this work, a rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for the determination of ledipasvir, sofosbuvir and its metabolite GS-331007 in rat plasma was developed. The analytes and the internal standard (diazepam) were separated on an Acquity UPLC BEH C18 chromatography column (2.1mm×50mm, 1.7μm) using gradient elution with a mobile phase of acetonitrile and 0.1% formic acid in water at a flow rate of 0.4mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 889.8→130.1 for ledipasvir, m/z 530.3→243.1 for sofosbuvir, m/z 261.5→113.1 for GS-331007 and m/z 285.2→193.1 for diazepam (IS) using a positive electrospray ionization interface. The method was validated over a concentration range of 2-500ng/mL for ledipasvir, 10-2000ng/mL for sofosbuvir and 10-2000ng/mL for GS-331007. Total time for each chromatography was 3.0min. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels exhibited relative standard deviations (RSD)<10.2% and the accuracy values ranged from -9.8% to 11.2%. The method was successfully applied to a pharmacokinetic study of ledipasvir, sofosbuvir and GS-331007 in rats.

  3. Development of an LC-MS/MS method for simultaneous determination of memantine and donepezil in rat plasma and its application to pharmacokinetic study.

    PubMed

    Bhateria, Manisha; Ramakrishna, Rachumallu; Pakala, Dora Babu; Bhatta, Rabi Sankar

    2015-09-15

    Recently, a fixed dose combination (FDC) of memantine (MM) and donepezil (DPZ) has been approved for the treatment of Alzheimer's disease (AD). In the present work, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of MM and DPZ was developed and validated in rat plasma over the linearity range of 0.2-400ng/mL using amantadine (AM) as an internal standard. Both the analytes and IS were extracted using one step liquid-liquid extraction procedure. The analytes were separated on C18 reversed phase column with mobile phase consisting of a mixture of methanol and 10mM ammonium acetate, pH 5 (92:8 v/v) at a flow rate of 0.7mL/min. The detection of the analytes was done on triple quadrupole mass spectrometer operated in positive electrospray ionization mode (ESI) and quantified using multiple reaction monitoring (MRM). The method was fully validated in terms of linearity, accuracy, precision, recovery, matrix effect, dilution integrity, carry-over effect and stability. The within- and between-run precisions were <10% and accuracy was all within ±10%. The mean recovery of MM and DPZ was found to be greater than 80%. The % RSD value at higher as well as lower concentration was well within the acceptable range (±15%) in all the stability experiments. The method was successfully applied to the oral pharmacokinetics and drug-drug interaction study of MM and DPZ in male Sprague Dawley (SD) rats.

  4. LC-MS/MS methods for the determination of edaravone and/or taurine in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Tang, Dao-quan; Bian, Ting-ting; Zheng, Xiao-xiao; Li, Ying; Wu, Xiao-wen; Li, Yin-jie; Du, Qian; Jiang, Shui-shi

    2014-09-01

    Three liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods were respectively developed and validated for the simultaneous or independent determination of taurine and edaravone in rat plasma using 3-methyl-1-p-tolyl-5-pyrazolone and sulfanilic acid as the internal standards (IS). Chromatographic separations were achieved on an Agilent Zorbax SB-Aq (100 × 2.1 mm, 3.5 µm) column. Gradient 0.03% formic acid-methanol, isocratic 0.1% formic acid-methanol (90:10) and 0.02% formic acid-methanol (40:60) were respectively selected as the mobile phase for the simultaneous determination of two analytes, taurine or edaravone alone. The MS acquisition was performed in multiple reaction monitoring mode with a positive and negative electrospray ionization source. The mass transitions monitored were m/z [M + H](+) 175.1 → 133.0 and [M + H](+) 189.2 → 147.0 for edaravone and its IS, m/z [M - H](-) 124.1 → 80.0 and [M - H](-) 172.0 → 80.0 for taurine and its IS, respectively. The validated methods were successfully applied to study the pharmacokinetic interaction of taurine and edaravone in rats after independent intravenous administration and co-administration with a single dose. Our collective results showed that there were no significant alterations on the main pharmacokinetic parameters (area under concentration-time curve, mean residence time, half-life and clearance) of taurine and edaravone, implying that the proposed combination therapy was pharmacologically feasible.

  5. A comprehensive study of different gases in inductively coupled plasma torch operating at one atmosphere

    SciTech Connect

    Punjabi, Sangeeta B.; Joshi, N. K.; Mangalvedekar, H. A.; Lande, B. K.; Das, A. K.; Kothari, D. C.

    2012-01-15

    A numerical study is done to understand the possible operating regimes of RF-ICP torch (3 MHz, 50 kW) using different gases for plasma formation at atmospheric pressure. A two dimensional numerical simulation of RF-ICP torch using argon, nitrogen, oxygen, and air as plasma gas has been investigated using computational fluid dynamic (CFD) software fluent{sup (c)}. The operating parameters varied here are central gas flow, sheath gas flow, RF-power dissipated in plasma, and plasma gas. The temperature contours, flow field, axial, and radial velocity profiles were investigated under different operating conditions. The plasma resistance, inductance of the torch, and the heat distribution for various plasma gases have also been investigated. The plasma impedance of ICP torch varies with different operating parameters and plays an important role for RF oscillator design and power coupling. These studies will be useful to decide the design criteria for ICP torches required for different material processing applications.

  6. Numerical Study on Microwave Scattering by Various Plasma Objects

    NASA Astrophysics Data System (ADS)

    Wang, Guibin; Zhang, Lin; He, Feng; Ouyang, Jiting

    2016-08-01

    The scattering features of microwave (MW) by planar plasma layer, plasma column and plasma-column array under different parameters have been numerically studied by the finite-difference time-domain (FDTD) method. The effects of the plasma frequency and electron collision rate on MW's reflectance, transmittance and absorptance are examined. The results show that for the planar plasma layer, the electron collision plays an important role in MW absorption and the reduction of wave reflection. In the plasma column condition, strong scattering occurs in certain directions. The scattering pattern depends on the plasma frequency, electron collision rate and column radius. A collisional, non-planar shaped plasma object like the plasma-column array can reduce significantly the wave reflection comparing with the planar plasma layer.

  7. Characterizations of atmospheric pressure low temperature plasma jets and their applications

    NASA Astrophysics Data System (ADS)

    Karakas, Erdinc

    2011-12-01

    Atmospheric pressure low temperature plasma jets (APLTPJs) driven by short pulses have recently received great attention because of their potential in biomedical and environmental applications. This potential is due to their user-friendly features, such as low temperature, low risk of arcing, operation at atmospheric pressure, easy handheld operation, and low concentration of ozone generation. Recent experimental observations indicate that an ionization wave exists and propagates along the plasma jet. The plasma jet created by this ionization wave is not a continuous medium but rather consists of a bullet-like-structure known as "Plasma Bullet". More interestingly, these plasma bullets actually have a donut-shaped makeup. The nature of the plasma bullet is especially interesting because it propagates in the ambient air at supersonic velocities without any externally applied electric field. In this dissertation, experimental insights are reported regarding the physical and chemical characteristics of the APLTPJs. The dynamics of the plasma bullet are investigated by means of a high-speed ICCD camera. A plasma bullet propagation model based on the streamer theory is confirmed with adequate explanations. It is also found that a secondary discharge, ignited by the charge accumulation on the dielectric electrode surfaces at the end of the applied voltage, interrupts the plasma bullet propagation due to an opposing current along the ionization channel. The reason for this interesting phenomenon is explained in detail. The plasma bullet comes to an end when the helium mole fraction along the ionization channel, or applied voltage, or both, are less than some critical values. The presence of an inert gas channel in the surrounding air, such as helium or argon, has a critical role in plasma bullet formation and propagation. For this reason, a fluid dynamics study is employed by a commercially available simulation software, COMSOL, based on finite element method. Spatio

  8. Development in Diagnostics Application to Control Advanced Tokamak Plasma

    SciTech Connect

    Koide, Y.

    2008-03-12

    For continuous operation expected in DEMO, all the plasma current must be non-inductively driven, with self-generated neoclassical bootstrap current being maximized. The control of such steady state high performance tokamak plasma (so-called 'Advanced Tokamak Plasma') is a challenge because of the strong coupling between the current density, the pressure profile and MHD stability. In considering diagnostic needs for the advanced tokamak research, diagnostics for MHD are the most fundamental, since discharges which violate the MHD stability criteria either disrupt or have significantly reduced confinement. This report deals with the development in diagnostic application to control advanced tokamak plasma, with emphasized on recent progress in active feedback control of the current profile and the pressure profile under DEMO-relevant high bootstrap-current fraction. In addition, issues in application of the present-day actuators and diagnostics for the advanced control to DEMO will be briefly addressed, where port space for the advanced control may be limited so as to keep sufficient tritium breeding ratio (TBR)

  9. Non-thermal atmospheric pressure HF plasma source: generation of nitric oxide and ozone for bio-medical applications

    NASA Astrophysics Data System (ADS)

    Kühn, S.; Bibinov, N.; Gesche, R.; Awakowicz, P.

    2010-01-01

    A new miniature high-frequency (HF) plasma source intended for bio-medical applications is studied using nitrogen/oxygen mixture at atmospheric pressure. This plasma source can be used as an element of a plasma source array for applications in dermatology and surgery. Nitric oxide and ozone which are produced in this plasma source are well-known agents for proliferation of the cells, inhalation therapy for newborn infants, disinfection of wounds and blood ozonation. Using optical emission spectroscopy, microphotography and numerical simulation, the gas temperature in the active plasma region and plasma parameters (electron density and electron distribution function) are determined for varied nitrogen/oxygen flows. The influence of the gas flows on the plasma conditions is studied. Ozone and nitric oxide concentrations in the effluent of the plasma source are measured using absorption spectroscopy and electro-chemical NO-detector at variable gas flows. Correlations between plasma parameters and concentrations of the particles in the effluent of the plasma source are discussed. By varying the gas flows, the HF plasma source can be optimized for nitric oxide or ozone production. Maximum concentrations of 2750 ppm and 400 ppm of NO and O3, correspondingly, are generated.

  10. Distinctive plume formation in atmospheric Ar and He plasmas in microwave frequency band and suitability for biomedical applications

    SciTech Connect

    Lee, H. Wk.; Kang, S. K.; Won, I. H.; Kim, H. Y.; Kwon, H. C.; Sim, J. Y.; Lee, J. K.

    2013-12-15

    Distinctive discharge formation in atmospheric Ar and He plasmas was observed in the microwave frequency band using coaxial transmission line resonators. Ar plasmas formed a plasma plume whereas He formed only confined plasmas. As the frequency increased from 0.9 GHz to 2.45 GHz, the Ar plasma exhibited contraction and filamentation, and the He plasmas were constricted. Various powers and gas flow rates were applied to identify the effect of the electric field and gas flow rate on plasma plume formation. The He plasmas were more strongly affected by the electric field than the Ar plasmas. The breakdown and sustain powers yielded opposite results from those for low-frequency plasmas (∼kHz). The phenomena could be explained by a change in the dominant ionization process with increasing frequency. Penning ionization and the contribution of secondary electrons in sheath region reduced as the frequency increased, leading to less efficient ionization of He because its ionization and excitation energies are higher than those of Ar. The emission spectra showed an increase in the NO and N{sub 2} second positive band in both the Ar and He plasmas with increasing frequency whereas the hydroxyl radical and atomic O peaks did not increase with increasing frequency but were highest at particular frequencies. Further, the frequency effect of properties such as the plasma impedance, electron density, and device efficiency were presented. The study is expected to be helpful for determining the optimal conditions of plasma systems for biomedical applications.

  11. Simultaneous determination of apatinib and its four major metabolites in human plasma using liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.

    PubMed

    Ding, Juefang; Chen, Xiaoyan; Dai, Xiaojian; Zhong, Dafang

    2012-05-01

    Apatinib, also known as YN968D1, is a novel antiangiogenic agent that selectively inhibits vascular endothelial growth factor receptor-2. Currently, apatinib is undergoing phase II/III clinical trials in China for the treatment of solid tumors. Apatinib is extensively metabolized in humans, and its major metabolites in circulation include cis-3-hydroxy-apatinib (M1-1), trans-3-hydroxy-apatinib (M1-2), apatinib-25-N-oxide (M1-6), and cis-3-hydroxy-apatinib-O-glucuronide (M9-2). To investigate the pharmacokinetics of apatinib and its four major metabolites in patients with advanced colorectal cancer, a sensitive and selective liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of apatinib, M1-1, M1-2, M1-6, and M9-2 in human plasma. After a simple protein precipitation using acetonitrile as the precipitation solvent, all the analytes and the internal standard vatalanib were separated on a Zorbax Eclipse XDB C(18) column (50 mm × 4.6 mm, 1.8 μm, Agilent) using acetonitrile: 5 mmol/L ammonium acetate with 0.1% formic acid as the mobile phase with gradient elution. A chromatographic total run time of 9 min was achieved. Mass spectrometry detection was conducted through electrospray ionization in positive ion multiple reaction monitoring modes. The method was linear over the concentration range of 3.00-2000 ng/mL for each analyte. The lower limit of quantification for each analyte was 3.00 ng/mL. The intra-assay precision for all the analytes was less than 11.3%, the inter-assay precision was less than 13.8%, and the accuracy was between -5.8% and 3.3%. The validated method was successfully applied to a clinical pharmacokinetic study following oral administration of 500 mg apatinib mesylate in patients with advanced colorectal cancer. PMID:22503745

  12. Rapid and sensitive LC-MS/MS method for the determination of auraptene in rat plasma and its application in a pharmacokinetic and bioavailability study in rats.

    PubMed

    Ye, X D; Ouyang, H; Zhong, L Y; Li, T E; Rao, X Y; Feng, Y L; Yang, W L

    2016-01-01

    A simple, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of auraptene, a constituent isolated from Fructus aurantii with potential to combat Alzheimer's disease, in rat plasma. Rat plasma samples were pretreated by protein precipitation with methanol. The analytes were separated by a Waters Sun Fire C18 column (50 mm x 2 mm, 5 μm) and eluted with 1:1000 methanol and formic acid/water (v/v) mobile phase with a flow rate of 0.5 mL/min. Multiple reaction monitoring was used to monitor the transition of the deprotonated auraptene molecule with an m/z of 299.3 [M+H](+), to the product ion with an m/z of 162.9 [M+H](+). Progesterone, with an m/z of 315.2→ 96.9 was used as an internal standard. The limits of detection and of quantification of auraptene in the rat plasma were 1 and 5 ng/mL, respectively. The method was linear in the concentration range of 20- 2000 ng/mL with coefficient correlation of 0.9956. After auraptene (100 mg/kg, p.o.) administration, the maximum plasma concentration and the time taken to reach maximum concentration were 1719.5 ± 384.3 g/mL and 108.0 ± 25.3 min, respectively. The elimination half-life was 108.0 ± 25.3 for auraptene (100 mg/kg, p.o.) and 3.0 ± 0 min for auraptene (2 mg/kg, i.v.). The oral bioavailability was about 8.5%. PMID:27420975

  13. Parts application handbook study

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The requirements for a NASA application handbook for standard electronic parts are determined and defined. This study concentrated on identifying in detail the type of information that designers and parts engineers need and expect in a parts application handbook for the effective application of standard parts on NASA projects.

  14. Studies of Ion Beam Charge Neutralization by Ferroelectric Plasma Sources

    NASA Astrophysics Data System (ADS)

    Stepanov, A.; Gilson, E. P.; Grisham, L.; Davidson, R. C.

    2013-10-01

    Space-charge forces limit the possible transverse compression of high perveance ion beams that are used in ion-beam-driven high energy density physics applications; the minimum radius to which a beam can be focused is an increasing function of perveance. The limit can be overcome if a plasma is introduced in the beam path between the focusing element and the target in order to neutralize the space charge of the beam. This concept has been implemented on the Neutralized Drift Compression eXperiment (NDCX) at LBNL using Ferroelectric Plasma Sources (FEPS). In our experiment at PPPL, we propagate a perveance-dominated ion beam through a FEPS to study the effect of the neutralizing plasma on the beam envelope and its evolution in time. A 30-60 keV space-charge-dominated Argon beam is focused with an Einzel lens into a FEPS located at the beam waist. The beam is intercepted downstream from the FEPS by a movable Faraday cup that provides time-resolved 2D current density profiles of the beam spot on target. We report results on: (a) dependence of charge neutralization on FEPS plasma density; (b) effects on beam emittance, and (c) time evolution of the beam envelope after the FEPS pulse. Research supported by the U.S. Department of Energy.

  15. Magneto-plasma sail: An engineering satellite concept and its application for outer planet missions

    NASA Astrophysics Data System (ADS)

    Yamakawa, Hiroshi; Funaki, Ikkoh; Nakayama, Yoshinori; Fujita, Kazuhisa; Ogawa, Hiroyuki; Nonaka, Satoshi; Kuninaka, Hitoshi; Sawai, Shujiro; Nishida, Hiroyuki; Asahi, Ryusuke; Otsu, Hirotaka; Nakashima, Hideki

    2006-10-01

    The magneto-plasma sail (mini-magnetospheric plasma propulsion) produces the propulsive force due to the interaction between the artificial magnetic field around the spacecraft inflated by the plasma and the solar wind erupted from the Sun with a speed of 300 800 km/s. The principle of the magneto-plasma sail is based on the magnetic sail whose original concept requires a huge mechanical coil structure, which produces a large magnetic field to capture the energy of the solar wind. Meanwhile in the case of the magneto-plasma sail, the magnetic field will be expanded by the inertia of plasma flow to a few tens of kilometer in diameter, resulting in a thrust of a few Newton R. Winglee's group of the University of Washington originally proposed the idea of magnetic field inflation by the plasma. This paper investigates the characteristics of the magneto-plasma sail by comparing it with the other low-thrust propulsion systems (i.e., electric propulsion and solar sail), and the potential of its application to near future outer planet missions is studied. Furthermore, an engineering validation satellite concept is proposed in order to confirm the propulsion system specification and operation methodology. The main features are summarized as: (1) The satellite mass is around 180 kg assuming the H-IIA piggyback launch. (2) Since the magnetopause of the Earth magnetosphere is about 10 Re at Sun side and the bow shock is located at about 13 Re from the Earth, the satellite is injected into an orbit with 250 km perigee altitude and 20 Re apogee distance where apogee is located at the Sun side. (3) The magneto-plasma sail is turned on only in the vicinity of apogee outside the Earth's magnetosphere. (4) The thrust is estimated by the orbit determination result, and the plasma wind monitor is installed on the satellite to establish the relationship between the solar wind and the thrust.

  16. Magneto plasma sail: an engineering satellite concept and its application for outer planet missions

    NASA Astrophysics Data System (ADS)

    Yamakawa, Hiroshi; Funaki, Ikkoh; Nakayama, Yoshinori; Fujita, Kazuhisa; Ogawa, Hiroyuki; Nonaka, Satoshi; Kuninaka, Hitoshi; Sawai, Shujiro; Nishida, Hiroyuki; Asahi, Ryusuke; Otsu, Hirotaka; Nakashima, Hideki

    2003-11-01

    The magneto-plasma sail (mini-magnetospheric plasma propulsion) produces the propulsive force due to the interaction between the artificial magnetic field around the spacecraft inflated by the plasma and the solar wind erupted from the Sun with a speed of 300~800 km/s. The principle of the magneto-plasma sail is based on the magnetic sail whose original concept requires a huge mechanical coil structure, which produces a large magnetic field to capture the energy of the solar wind. Meanwhile in the case of the magneto-plasma sail, the magnetic field will be expanded by the inertia of plasma flow to a few tens of km in diameter, resulting in a thrust of a few N. R. Winglee's group of the University of Washington originally proposed the idea of magnetic field inflation by the plasma. This paper investigates the characteristics of the magneto-plasma sail by comparing it with the other low-thrust propulsion systems (i.e., electric propulsion and solar sail), and the potential of its application to near future outer planet missions is studied. Furthermore, an engineering validation satellite concept is proposed in order to confirm the propulsion system specification and operation methodology. The main features are summarized as: 1) The satellite mass is around 180kg assuming the H-IIA piggyback launch. 2) Since the magnetopause of the Earth magnetosphere is about 10Re at Sun side and the bow shock is located at about 13Re from the Earth, the satellite is injected into an orbit with 250km perigee altitude and 20Re apogee distance where apogee is located at the Sun side. 3) The magneto-plasma sail is turned on only in the vicinity of apogee outside the Earth's magnetosphere. 4) The thrust is estimated by the orbit determination result, and the plasma wind monitor is installed on the satellite to establish the relationship between the solar wind and the thrust.

  17. Naphthalene and acenaphthene decomposition by electron beam generated plasma application

    SciTech Connect

    Ostapczuk, A.; Hakoda, T.; Shimada, A.; Kojima, T.

    2008-08-15

    The application of non-thermal plasma generated by electron beam (EB) was investigated in laboratory scale to study decomposition of polycyclic aromatic hydrocarbons like naphthalene and acenaphthene in flue gas. PAH compounds were treated by EB with the dose up to 8 kGy in dry and humid base gas mixtures. Experimentally established G-values gained 1.66 and 3.72 mol/100 eV for NL and AC at the dose of 1 kGy. NL and AC removal was observed in dry base gas mixtures showing that the reaction with OH radical is not exclusive pathway to initialize PAH decomposition; however in the presence of water remarkably higher decomposition efficiency was observed. As by-products of NL decomposition were identified compounds containing one aromatic ring and oxygen atoms besides CO and CO{sub 2}. It led to the conclusion that PAH decomposition process in humid flue gas can be regarded as multi-step oxidative de-aromatization analogical to its atmospheric chemistry.

  18. Simultaneous determination of 14-thienyl methylene matrine and matrine in rat plasma by high-performance liquid chromatography-tandem mass spectrometry and its application in a pharmacokinetic study.

    PubMed

    Jiang, Minjie; Wang, Lisheng; Jiang, Weizhe; Huang, Shulin

    2015-01-01

    A rapid, sensitive and selective high-performance liquid chromatography-tandem mass spectrometric method (HPLC-MS) has been developed and validated for the simultaneous determination of 14-thienyl methylene matrine (TMM) and matrine (MT) in rat plasma in the present study. The analytes were separated on a C18 column (1.9 μm, 2.1 mm × 100 mm) with a security guard C18 column (5 μm, 2.1 mm × 10 mm) and a triple-quadrupole mass spectrometry equipped with an electrospray ionization (ESI) source was applied for detection. With pseudoephedrine hydrochloride as internal standard, sample pretreatment involved in a one-step protein precipitation with isopropanol:ethyl acetate (v/v, 20:80). The method was linear over the concentration ranges of 5-1000 ng/ml for TMM and 10-2000 ng/ml for MT. The intra-day and inter-day relative standard deviations (RSD) were less than 15% and the relative errors (RE) were all within 15%. The proposed method enables unambiguous identification and quantification of TMM and MT in vivo. This was the first report on determination of the TMM and MT in rat plasma after oral administration of TMM. The results provided a meaningful basis for evaluating the clinical applications of the medicine.

  19. Scalable graphene production: perspectives and challenges of plasma applications.

    PubMed

    Levchenko, Igor; Ostrikov, Kostya Ken; Zheng, Jie; Li, Xingguo; Keidar, Michael; B K Teo, Kenneth

    2016-05-19

    Graphene, a newly discovered and extensively investigated material, has many unique and extraordinary properties which promise major technological advances in fields ranging from electronics to mechanical engineering and food production. Unfortunately, complex techniques and high production costs hinder commonplace applications. Scaling of existing graphene production techniques to the industrial level without compromising its properties is a current challenge. This article focuses on the perspectives and challenges of scalability, equipment, and technological perspectives of the plasma-based techniques which offer many unique possibilities for the synthesis of graphene and graphene-containing products. The plasma-based processes are amenable for scaling and could also be useful to enhance the controllability of the conventional chemical vapour deposition method and some other techniques, and to ensure a good quality of the produced graphene. We examine the unique features of the plasma-enhanced graphene production approaches, including the techniques based on inductively-coupled and arc discharges, in the context of their potential scaling to mass production following the generic scaling approaches applicable to the existing processes and systems. This work analyses a large amount of the recent literature on graphene production by various techniques and summarizes the results in a tabular form to provide a simple and convenient comparison of several available techniques. Our analysis reveals a significant potential of scalability for plasma-based technologies, based on the scaling-related process characteristics. Among other processes, a greater yield of 1 g × h(-1) m(-2) was reached for the arc discharge technology, whereas the other plasma-based techniques show process yields comparable to the neutral-gas based methods. Selected plasma-based techniques show lower energy consumption than in thermal CVD processes, and the ability to produce graphene flakes of

  20. Scalable graphene production: perspectives and challenges of plasma applications.

    PubMed

    Levchenko, Igor; Ostrikov, Kostya Ken; Zheng, Jie; Li, Xingguo; Keidar, Michael; B K Teo, Kenneth

    2016-05-19

    Graphene, a newly discovered and extensively investigated material, has many unique and extraordinary properties which promise major technological advances in fields ranging from electronics to mechanical engineering and food production. Unfortunately, complex techniques and high production costs hinder commonplace applications. Scaling of existing graphene production techniques to the industrial level without compromising its properties is a current challenge. This article focuses on the perspectives and challenges of scalability, equipment, and technological perspectives of the plasma-based techniques which offer many unique possibilities for the synthesis of graphene and graphene-containing products. The plasma-based processes are amenable for scaling and could also be useful to enhance the controllability of the conventional chemical vapour deposition method and some other techniques, and to ensure a good quality of the produced graphene. We examine the unique features of the plasma-enhanced graphene production approaches, including the techniques based on inductively-coupled and arc discharges, in the context of their potential scaling to mass production following the generic scaling approaches applicable to the existing processes and systems. This work analyses a large amount of the recent literature on graphene production by various techniques and summarizes the results in a tabular form to provide a simple and convenient comparison of several available techniques. Our analysis reveals a significant potential of scalability for plasma-based technologies, based on the scaling-related process characteristics. Among other processes, a greater yield of 1 g × h(-1) m(-2) was reached for the arc discharge technology, whereas the other plasma-based techniques show process yields comparable to the neutral-gas based methods. Selected plasma-based techniques show lower energy consumption than in thermal CVD processes, and the ability to produce graphene flakes of

  1. Scalable graphene production: perspectives and challenges of plasma applications

    NASA Astrophysics Data System (ADS)

    Levchenko, Igor; Ostrikov, Kostya (Ken); Zheng, Jie; Li, Xingguo; Keidar, Michael; B. K. Teo, Kenneth

    2016-05-01

    Graphene, a newly discovered and extensively investigated material, has many unique and extraordinary properties which promise major technological advances in fields ranging from electronics to mechanical engineering and food production. Unfortunately, complex techniques and high production costs hinder commonplace applications. Scaling of existing graphene production techniques to the industrial level without compromising its properties is a current challenge. This article focuses on the perspectives and challenges of scalability, equipment, and technological perspectives of the plasma-based techniques which offer many unique possibilities for the synthesis of graphene and graphene-containing products. The plasma-based processes are amenable for scaling and could also be useful to enhance the controllability of the conventional chemical vapour deposition method and some other techniques, and to ensure a good quality of the produced graphene. We examine the unique features of the plasma-enhanced graphene production approaches, including the techniques based on inductively-coupled and arc discharges, in the context of their potential scaling to mass production following the generic scaling approaches applicable to the existing processes and systems. This work analyses a large amount of the recent literature on graphene production by various techniques and summarizes the results in a tabular form to provide a simple and convenient comparison of several available techniques. Our analysis reveals a significant potential of scalability for plasma-based technologies, based on the scaling-related process characteristics. Among other processes, a greater yield of 1 g × h-1 m-2 was reached for the arc discharge technology, whereas the other plasma-based techniques show process yields comparable to the neutral-gas based methods. Selected plasma-based techniques show lower energy consumption than in thermal CVD processes, and the ability to produce graphene flakes of various

  2. Quantification of theobromine and caffeine in saliva, plasma and urine via liquid chromatography-tandem mass spectrometry: a single analytical protocol applicable to cocoa intervention studies.

    PubMed

    Ptolemy, Adam S; Tzioumis, Emma; Thomke, Arjun; Rifai, Sami; Kellogg, Mark

    2010-02-01

    Targeted analyses of clinically relevant metabolites in human biofluids often require extensive sample preparation (e.g., desalting, protein removal and/or preconcentration) prior to quantitation. In this report, a single ultra-centrifugation based sample pretreatment combined with a designed liquid chromatography-tandem mass spectrometry (LC-MS/MS) protocol provides selective quantification of 3,7-dimethylxanthine (theobromine) and 1,3,7-trimethylxanthine (caffeine) in human saliva, plasma and urine samples. The optimized chromatography permitted elution of both analytes within 1.3 min of the applied gradient. Positive-mode electrospray ionization and a triple quadruple MS/MS instrument operated in multiple reaction mode were used for detection. (13)C(3) isotopically labeled caffeine was included as an internal standard to improve accuracy and precision. Implementing a 20-fold dilution of the isolated low MW biofluid fraction prior to injection effectively minimized the deleterious contributions of all three matrices to quantitation. The assay was linear over a 160-fold concentration range from 2.5 to 400 micromol L(-1) for both theobromine (average R(2) 0.9968) and caffeine (average R(2) 0.9997) respectively. Analyte peak area variations for 2.5 micromol L(-1) caffeine and theobromine in saliva, plasma and urine ranged from 5 and 10% (intra-day, N=10) to 9 and 13% (inter-day, N=25) respectively. The intra- and inter-day precision of theobromine and caffeine elution times were 3 and <1% for all biofluids and concentrations tested. Recoveries for caffeine and theobromine ranged from 114 to 118% and 99 to 105% at concentration levels of 10 and 300 micromol L(-1). This validated protocol also permitted the relative saliva, plasma and urine distribution of both theobromine and caffeine to be quantified following a cocoa intervention.

  3. Quantification of theobromine and caffeine in saliva, plasma and urine via liquid chromatography-tandem mass spectrometry: a single analytical protocol applicable to cocoa intervention studies.

    PubMed

    Ptolemy, Adam S; Tzioumis, Emma; Thomke, Arjun; Rifai, Sami; Kellogg, Mark

    2010-02-01

    Targeted analyses of clinically relevant metabolites in human biofluids often require extensive sample preparation (e.g., desalting, protein removal and/or preconcentration) prior to quantitation. In this report, a single ultra-centrifugation based sample pretreatment combined with a designed liquid chromatography-tandem mass spectrometry (LC-MS/MS) protocol provides selective quantification of 3,7-dimethylxanthine (theobromine) and 1,3,7-trimethylxanthine (caffeine) in human saliva, plasma and urine samples. The optimized chromatography permitted elution of both analytes within 1.3 min of the applied gradient. Positive-mode electrospray ionization and a triple quadruple MS/MS instrument operated in multiple reaction mode were used for detection. (13)C(3) isotopically labeled caffeine was included as an internal standard to improve accuracy and precision. Implementing a 20-fold dilution of the isolated low MW biofluid fraction prior to injection effectively minimized the deleterious contributions of all three matrices to quantitation. The assay was linear over a 160-fold concentration range from 2.5 to 400 micromol L(-1) for both theobromine (average R(2) 0.9968) and caffeine (average R(2) 0.9997) respectively. Analyte peak area variations for 2.5 micromol L(-1) caffeine and theobromine in saliva, plasma and urine ranged from 5 and 10% (intra-day, N=10) to 9 and 13% (inter-day, N=25) respectively. The intra- and inter-day precision of theobromine and caffeine elution times were 3 and <1% for all biofluids and concentrations tested. Recoveries for caffeine and theobromine ranged from 114 to 118% and 99 to 105% at concentration levels of 10 and 300 micromol L(-1). This validated protocol also permitted the relative saliva, plasma and urine distribution of both theobromine and caffeine to be quantified following a cocoa intervention. PMID:20045386

  4. HPLC method with solid-phase extraction for determination of (R)- and (S)-ketoprofen in plasma without caffeine interference: application to pharmacokinetic studies in rats.

    PubMed

    López-Muñoz, Francisco Javier; Vara Gama, Nancy; Soria-Arteche, Olivia; Hurtado y de la Peña, Marcela; Domínguez-Ramírez, Adriana Miriam; Medina López, José Raúl

    2014-01-01

    A fast and reproducible high-performance liquid chromatography method has been developed for the determination of (R)- and (S)-ketoprofen. Ketoprofen enantiomers were determined in plasma samples (50 µL), after solid-phase extraction, using diclofenac as internal standard. Analyses were performed on a (S, S)-Whelk-O 1 stainless steel column (5 µm, 250 × 4.6 mm) using hexane-ethanol-acetic acid (93:7:0.5, v/v/v) as the mobile phase and detection at 254 nm. The method was selective for ketoprofen enantiomers in the presence of caffeine and endogenous plasma compounds. Standard curves were linear (R(2) > 0.999) over the concentration range of 0.25-12.50 and 0.25 µg/mL was taken as the limit of quantification. The intra- and interday precision (relative standard deviation) values were <15.0% and the accuracy (relative error) was within ±12.0% at 1.0, 5.0 and 10.0 µg/mL. Enantiomer recoveries yielded 100.0 ± 15%. No significant differences were determined in plasma samples stored at room temperature for 24.0 h, after two freeze-thaw cycles, and between 0 and 4 weeks at -20°C (P > 0.05). The validated method was successfully applied in determination of (S)-ketoprofen in Wistar rats after oral administration of 3.2 mg/kg of (S)-ketoprofen alone or 3.2 mg/kg of (S)-ketoprofen + 17.8 mg/kg of caffeine.

  5. HPLC method with solid-phase extraction for determination of (R)- and (S)-ketoprofen in plasma without caffeine interference: application to pharmacokinetic studies in rats.

    PubMed

    López-Muñoz, Francisco Javier; Vara Gama, Nancy; Soria-Arteche, Olivia; Hurtado y de la Peña, Marcela; Domínguez-Ramírez, Adriana Miriam; Medina López, José Raúl

    2014-01-01

    A fast and reproducible high-performance liquid chromatography method has been developed for the determination of (R)- and (S)-ketoprofen. Ketoprofen enantiomers were determined in plasma samples (50 µL), after solid-phase extraction, using diclofenac as internal standard. Analyses were performed on a (S, S)-Whelk-O 1 stainless steel column (5 µm, 250 × 4.6 mm) using hexane-ethanol-acetic acid (93:7:0.5, v/v/v) as the mobile phase and detection at 254 nm. The method was selective for ketoprofen enantiomers in the presence of caffeine and endogenous plasma compounds. Standard curves were linear (R(2) > 0.999) over the concentration range of 0.25-12.50 and 0.25 µg/mL was taken as the limit of quantification. The intra- and interday precision (relative standard deviation) values were <15.0% and the accuracy (relative error) was within ±12.0% at 1.0, 5.0 and 10.0 µg/mL. Enantiomer recoveries yielded 100.0 ± 15%. No significant differences were determined in plasma samples stored at room temperature for 24.0 h, after two freeze-thaw cycles, and between 0 and 4 weeks at -20°C (P > 0.05). The validated method was successfully applied in determination of (S)-ketoprofen in Wistar rats after oral administration of 3.2 mg/kg of (S)-ketoprofen alone or 3.2 mg/kg of (S)-ketoprofen + 17.8 mg/kg of caffeine. PMID:24368338

  6. A rapid and highly sensitive UPLC-MS-MS method for the quantification of zolpidem tartrate in human EDTA plasma and its application to pharmacokinetic study.

    PubMed

    Reddy, Dendhi Chandrapal; Bapuji, Akula Tukaram; Rao, Vepakomma Suryanarayana; Himabindu, Vurimindi; Ravinder, Sreedasyam

    2012-07-01

    A rapid and high sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed and validated for the quantification of zolpidem in human EDTA plasma using ondansetron (IS) as an internal standard. The analyte and IS were extracted from human plasma using ethyl acetate and separated on a C18 column (Inertsil-ODS, 5 µm, 4.6 × 50 mm) interfaced with a triple quadrupole tandem mass spectrometer. The mobile phase, which consisted of a mixture of methanol and 20 mM ammonium formate (pH 5.00 ± 0.05; 75:25 v/v), was injected at a flow rate of 0.40 mL/min. The retention times of zolpidem and IS were approximately 1.76 and 1.22. The LC run time was 3 min. The electrospray ionization source was operated in positive ion mode. Multiple reaction monitoring used the [M + H](+) ions m/z 308.13 → 235.21 for zolpidem and m/z 294.02 → 170.09 for the ondansetron, respectively. Five freeze-thaw cycles was established at -20 and -70°C.The linearity of the response/concentration curve was established in human EDTA plasma over the concentration range 0.10-149.83 ng/mL. The lower detection limit [(signal-to-noise (S/N) > 3] was 0.04 ng/mL and the lower limit of quantification (S/N > 10) was 0.10 ng/mL. This LC-MS-MS method was validated with intra-batch and inter-batch precision of 0.52-8.66.The intra-batch and inter-batch accuracy was 96.66-106.11. Recovery of zolpidem in human plasma was 87.00% and IS recovery was 81.60%. The primary pharmacokinetic parameters were T(max) (h) = (1.25 ± 0.725), C(max) (ng/mL) (127.80 ± 34.081), AUC(0→t), = (665.37 ± 320.982) and AUC(0→∞), 686.03 ± 342.952, respectively. PMID:22689921

  7. A solar powered handheld plasma source for microbial decontamination applications

    NASA Astrophysics Data System (ADS)

    Ni, Y.; Lynch, M. J.; Modic, M.; Whalley, R. D.; Walsh, J. L.

    2016-09-01

    A fully portable atmospheric pressure air plasma system is reported to be suitable for the microbial decontamination of both surfaces and liquids. The device operates in quiescent air, and includes an integrated battery which is charged from a solar cell and weighs less than 750 g, making it highly amenable for a wide variety of applications beyond the laboratory. Using particle imaging velocimetry to visualise air flows around the device, the geometric configuration of the plasma generating electrodes was enhanced to induce a gas flow on the order of 0.5 m s‑1 directed towards a sample placed downstream, thus improving the transport of plasma generated reactive species to the sample. The microbial decontamination efficiency of the system was assessed using potable water samples inoculated with common waterborne organisms Escherichia coli and Pseudomonas fluorescens. The reduction in the number of microorganisms was found to be in the range of 2–8 log and was strongly dependent on the plasma generation conditions.

  8. A solar powered handheld plasma source for microbial decontamination applications

    NASA Astrophysics Data System (ADS)

    Ni, Y.; Lynch, M. J.; Modic, M.; Whalley, R. D.; Walsh, J. L.

    2016-09-01

    A fully portable atmospheric pressure air plasma system is reported to be suitable for the microbial decontamination of both surfaces and liquids. The device operates in quiescent air, and includes an integrated battery which is charged from a solar cell and weighs less than 750 g, making it highly amenable for a wide variety of applications beyond the laboratory. Using particle imaging velocimetry to visualise air flows around the device, the geometric configuration of the plasma generating electrodes was enhanced to induce a gas flow on the order of 0.5 m s-1 directed towards a sample placed downstream, thus improving the transport of plasma generated reactive species to the sample. The microbial decontamination efficiency of the system was assessed using potable water samples inoculated with common waterborne organisms Escherichia coli and Pseudomonas fluorescens. The reduction in the number of microorganisms was found to be in the range of 2-8 log and was strongly dependent on the plasma generation conditions.

  9. [Study of ignition characteristic of DC voltage plasma ignitor].

    PubMed

    Wang, Feng; He, Li-Ming; Lan, Yu-Dan; Du, Hong-Liang

    2011-09-01

    The changing law between interelectrode current, discharge characteristic and jet characteristic of plasma ignitor under different inlet Ar pressure and working current was researched by adopting self-made plasma ignitor. Still, four channels CCD spectrometer was adopted to measure the spectrum characteristic at the exit of ignitor and electron temperature of plasma was calculated according to the spectrum characteristic. The results show that the interelectrode current gradually reduced with rising inlet Ar pressure; The jet length of plasma ignitor firstly increased then reduced with rising inlet Ar flowrate, and also increased with rising working current; The working current of plasma ignitor reduced with rising inlet Ar flowrate, and increased with rising source output current; the electron temperature of plasma ignitor jet increased with rising working current and reduced with rising Ar flowrate. The research results are of certain guidance meanings and reference values for the practical application of plasma ignition system in aeroengine.

  10. Determination of Pinaverium Bromide in Human Plasma by a Sensitive and Robust UPLC-MS-MS Method and Application to a Pharmacokinetic Study in Mexican Subjects.

    PubMed

    Patiño-Rodríguez, Omar; Zapata-Morales, Juan Ramón; Escobedo-Moratilla, Abraham; Díaz de León-Cabrero, Manuel; Torres-Roque, Irma; Pérez-Urizar, José

    2015-09-01

    A high-throughput ultra-performance liquid chromatography coupled to tandem mass spectrometry (LC-ESI-MS-MS) method was developed for the determination of pinaverium bromide in human plasma. Protein precipitation with acetonitrile was used to extract pinaverium and itraconazole (as internal standard) from 500 µL plasma samples. The chromatographic separation was achieved with an Acquity UPLC BEH C18 column (1.7 µm, 2.1 × 100 mm) using a mixture of acetonitrile-5 mM ammonium formate (80:20, v/v) as mobile phase. Isocratic elution at 0.3 mL/min was used. Detection was performed by positive ion electrospray tandem mass spectrometry on a XEVO TQ-S by multiple reaction monitoring mode. The mass transitions monitorized were as follows: m/z 511.2 → 230 for pinaverium bromide, and m/z 705.29 → 392.18 for the itraconazole. The method was validated over a concentration range of 12-12,000 pg/mL. The chromatographic method runtime is 2.5 min and was applied to characterize the pharmacokinetics of pinaverium bromide after the oral administration of 100 mg to healthy Mexican subjects. PMID:25862744

  11. Development and validation of a highly sensitive LC-MS/MS-ESI method for the determination of nobiletin in rat plasma: application to a pharmacokinetic study.

    PubMed

    Kumar, Avinash; Devaraj, V C; Giri, Kalpesh C; Giri, Sanjeev; Rajagopal, Sriram; Mullangi, Ramesh

    2012-12-01

    A highly sensitive, rapid assay method has been developed and validated for the estimation of nobiletin in rat plasma with liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive-ion mode. The assay procedure involves extraction of nobiletin and citalopram (internal standard, IS) from rat plasma with liquid-liquid extraction. Chromatographic separation was achieved using an isocratic mobile phase (0.2% formic acid-acetonitrile, 20:80, v/v) at a flow rate of 0.6 mL/min on an Atlantis dC₁₈ column (maintained at 40 ± 1 °C) with a total run time of 2.0 min. The MS/MS ion transitions monitored were 403.2 → 373.0 for nobiletin and 325.2 → 109.0 for IS. Method validation was performed as per Food and Drug Administration guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 0.05 ng/mL and the linearity range extended from 0.05 to 51.98 ng/mL. The intra- and inter-day precisions were in the range of 1.96-14.3 and 6.21-12.1, respectively.

  12. Sensitive liquid chromatography-tandem mass spectrometry method for the determination of cefixime in human plasma: application to a pharmacokinetic study.

    PubMed

    Meng, Fang; Chen, Xiaoyan; Zeng, Yalin; Zhong, Dafang

    2005-05-25

    A sensitive and selective liquid chromatographic-tandem mass spectrometric (LC-MS-MS) method was developed to determine cefixime ((6R,7R)-7-[(Z)-2-(2-amino-4-thiazolyl)-2-(carboxymethoxyimino)acetamido]-8-oxo-3-vinyl-5-thia-1-azabicyclo-[4,2,0]-oct-2-ene-2-carboxylic acid) in human plasma. After a simple protein precipitation using acetonitrile, the post-treatment samples were analyzed on a C(8) column interfaced with a triple quadrupole tandem mass spectrometer. Positive electrospray ionization was employed as the ionization source. The mobile phase consisted of acetonitrile-water-formic acid (40:60:0.5, v/v/v). The analyte and internal standard cefetamet were both detected by use of selected reaction monitoring mode. The method was linear in the concentration range of 0.05-8.0 microg/ml. The lower limit of quantification was 0.05 microg/ml. The intra- and inter-day relative standard deviation across three validation runs over the entire concentration range was less than 12.7%. The accuracy determined at three concentrations (0.05, 0.80 and 7.2 microg/ml for cefixime) was within +/-2.0% in terms of relative error. Each plasma sample was chromatographed within 3.5 min. The method herein described was successfully applied for the evaluation of pharmacokinetic profiles of cefixime capsule in 24 healthy volunteers.

  13. Rapid and sensitive determination of acetylsalicylic acid and salicylic acid in plasma using liquid chromatography-tandem mass spectrometry: application to pharmacokinetic study.

    PubMed

    Xu, Xiangrong; Koetzner, Lee; Boulet, Jamie; Maselli, Harry; Beyenhof, Jessica; Grover, Gary

    2009-09-01

    A simple and sensitive analytical method using liquid chromatography-tandem mass spectrometry (LC/MS/MS) for determination of acetylsalicylic acid (aspirin, ASA) and its major metabolite, salicylic acid (SA), in animal plasma has been developed and validated. Both ASA and SA in plasma samples containing potassium fluoride were extracted using acetonitrile (protein precipitation) with 0.1% formic acid in it. 6-Methoxysalicylic acid was used as the internal standard (IS). The compounds were separated on a reversed-phase column. The multiple reaction monitoring mode was used with ion transitions of m/z 178.9 --> 136.8, 137.0 --> 93.0 and 167.0 --> 123.0 for ASA, SA and IS, respectively. The lower limits of quantification for ASA and SA were 3 and 30 ng/mL, respectively. The developed method was successfully applied for the evaluation of pharmacokinetics of ASA and SA after p.o. and i.v. administration of 1 mg/kg to rats.

  14. Determination of Pinaverium Bromide in Human Plasma by a Sensitive and Robust UPLC-MS-MS Method and Application to a Pharmacokinetic Study in Mexican Subjects.

    PubMed

    Patiño-Rodríguez, Omar; Zapata-Morales, Juan Ramón; Escobedo-Moratilla, Abraham; Díaz de León-Cabrero, Manuel; Torres-Roque, Irma; Pérez-Urizar, José

    2015-09-01

    A high-throughput ultra-performance liquid chromatography coupled to tandem mass spectrometry (LC-ESI-MS-MS) method was developed for the determination of pinaverium bromide in human plasma. Protein precipitation with acetonitrile was used to extract pinaverium and itraconazole (as internal standard) from 500 µL plasma samples. The chromatographic separation was achieved with an Acquity UPLC BEH C18 column (1.7 µm, 2.1 × 100 mm) using a mixture of acetonitrile-5 mM ammonium formate (80:20, v/v) as mobile phase. Isocratic elution at 0.3 mL/min was used. Detection was performed by positive ion electrospray tandem mass spectrometry on a XEVO TQ-S by multiple reaction monitoring mode. The mass transitions monitorized were as follows: m/z 511.2 → 230 for pinaverium bromide, and m/z 705.29 → 392.18 for the itraconazole. The method was validated over a concentration range of 12-12,000 pg/mL. The chromatographic method runtime is 2.5 min and was applied to characterize the pharmacokinetics of pinaverium bromide after the oral administration of 100 mg to healthy Mexican subjects.

  15. A sensitive LC-MS/MS method for simultaneous determination of six flavonoids in rat plasma: application to a pharmacokinetic study of total flavonoids from mulberry leaves.

    PubMed

    He, Jun; Feng, Ying; Ouyang, Hui-Zi; Yu, Bin; Chang, Yan-Xu; Pan, Gui-Xiang; Dong, Gai-Ying; Wang, Tao; Gao, Xiu-Mei

    2013-10-01

    A simple and sensitive LC-MS/MS method has been developed and validated for the determination of rutin, isoquercitrin, astragalin, quercetin, kaempferol and isorhamnetin in rat plasma using naringin as the internal standard (IS). The plasma samples were pretreated and extracted by liquid-liquid extraction. Chromatographic separation was accomplished on a C18 column with a 10 min gradient elution using acetonitrile and 0.1% formic acid aqueous solution as mobile phase at a flow rate of 0.3 mL min(-1). A tandem mass spectrometric detection was conducted using multiple reaction monitoring (MRM) via an electrospray ionization (ESI) source and operating in the negative ionization mode. The lower limit of quantitation (LLOQ) of each analyte was lower than 1 ng mL(-1). Intra-day and inter-day precisions were less than 11.9%. The relative errors of accuracy were in the range of -9.2% to 6.1%. The mean recoveries of flavonoids and IS were higher than 53.8%. The proposed method was further applied to investigate the pharmacokinetics of all analytes after a single oral administration of total flavonoids from mulberry leaves to rats. PMID:23850933

  16. A sensitive LC-MS/MS method for simultaneous determination of six flavonoids in rat plasma: application to a pharmacokinetic study of total flavonoids from mulberry leaves.

    PubMed

    He, Jun; Feng, Ying; Ouyang, Hui-Zi; Yu, Bin; Chang, Yan-Xu; Pan, Gui-Xiang; Dong, Gai-Ying; Wang, Tao; Gao, Xiu-Mei

    2013-10-01

    A simple and sensitive LC-MS/MS method has been developed and validated for the determination of rutin, isoquercitrin, astragalin, quercetin, kaempferol and isorhamnetin in rat plasma using naringin as the internal standard (IS). The plasma samples were pretreated and extracted by liquid-liquid extraction. Chromatographic separation was accomplished on a C18 column with a 10 min gradient elution using acetonitrile and 0.1% formic acid aqueous solution as mobile phase at a flow rate of 0.3 mL min(-1). A tandem mass spectrometric detection was conducted using multiple reaction monitoring (MRM) via an electrospray ionization (ESI) source and operating in the negative ionization mode. The lower limit of quantitation (LLOQ) of each analyte was lower than 1 ng mL(-1). Intra-day and inter-day precisions were less than 11.9%. The relative errors of accuracy were in the range of -9.2% to 6.1%. The mean recoveries of flavonoids and IS were higher than 53.8%. The proposed method was further applied to investigate the pharmacokinetics of all analytes after a single oral administration of total flavonoids from mulberry leaves to rats.

  17. Atmospheric-pressure plasma jet characterization and applications on melanoma cancer treatment (B/16-F10)

    SciTech Connect

    Mashayekh, Shahriar; Rajaee, Hajar; Hassan, Zuhir M.; Akhlaghi, Morteza; Shokri, Babak

    2015-09-15

    A new approach in medicine is the use of cold plasma for various applications such as sterilization blood coagulation and cancer cell treatment. In this paper, a pin-to-hole plasma jet for biological applications has been designed and manufactured and characterized. The characterization includes power consumption via Lissajous method, thermal behavior of atmospheric-pressure plasma jet by using Infra-red camera as a novel method and using Speicair software to determine vibrational and transitional temperatures, and optical emission spectroscopy to determine the generated species. Treatment of Melanoma cancer cells (B16/F10) was also implemented, and tetrazolium salt dye (MTT assay) and flow cytometry were used to evaluate viability. Effect of ultraviolet photons on cancerous cells was also observed using an MgF{sub 2} crystal with MTT assay. Finally, in-vivo studies on C57 type mice were also done in order to have a better understanding of the effects in real conditions.

  18. Atmospheric-pressure plasma jet characterization and applications on melanoma cancer treatment (B/16-F10)

    NASA Astrophysics Data System (ADS)

    Mashayekh, Shahriar; Rajaee, Hajar; Akhlaghi, Morteza; Shokri, Babak; Hassan, Zuhir M.

    2015-09-01

    A new approach in medicine is the use of cold plasma for various applications such as sterilization blood coagulation and cancer cell treatment. In this paper, a pin-to-hole plasma jet for biological applications has been designed and manufactured and characterized. The characterization includes power consumption via Lissajous method, thermal behavior of atmospheric-pressure plasma jet by using Infra-red camera as a novel method and using Speicair software to determine vibrational and transitional temperatures, and optical emission spectroscopy to determine the generated species. Treatment of Melanoma cancer cells (B16/F10) was also implemented, and tetrazolium salt dye (MTT assay) and flow cytometry were used to evaluate viability. Effect of ultraviolet photons on cancerous cells was also observed using an MgF2 crystal with MTT assay. Finally, in-vivo studies on C57 type mice were also done in order to have a better understanding of the effects in real conditions.

  19. Derivation of uncertainty functions from validation studies in biological fluids: application to the analysis of caffeine and its major metabolites in human plasma samples.

    PubMed

    Gassner, Anne-Laure; Schappler, Julie; Feinberg, Max; Rudaz, Serge

    2014-08-01

    Procedures for estimating the measurement uncertainty (MU) of the concentration of a given analyte in a sample are of major concern for analytical chemists. Unfortunately, it is still unclear how and why MU should be assessed. While several possibilities exist, an appropriate approach consists in using method validation data for the evaluation of MU. This was demonstrated by a validation study achieved in the framework of a clinical study related to caffeine in sports medicine, where the results were used for the evaluation of MU. After validation of the method developed using ultra-high pressure liquid chromatography-mass spectrometry for caffeine and its three main metabolites, accuracy profiles were built for each analyte. The first important conclusion is that the developed method was valid for all compounds and met the given specifications for the application (fit for purpose). Relevant estimates of combined standard uncertainty were computed to obtain uncertainty functions, which allow obtaining values of MU as a function of the concentration of the analyte. The great advantage of both uncertainty function and uncertainty profile is the development of a continuous model that enables easy calculation of the standard, expanded and relative expanded uncertainty at any concentration within the validation domain. In fact, the expanded uncertainty interval is assumed to contain 95% of all possible measurements, regardless of the concentration. Finally, the uncertainty function enables the determination of the lowest limit of quantification by selecting adequate acceptance limits, with the limit of quantification being defined as the point where the relative uncertainty equals the acceptance limit threshold. It has to be noted that further discussions remain mandatory to establish which criteria should be applied to define an adequate decision threshold, and the proposal afforded in this work may open new avenues in this direction.

  20. A study of single and binary ion plasma expansion into laboratory-generated plasma wakes

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth Herbert, Jr.

    1988-01-01

    Plasma expansion into the wake of a large rectangular plate immersed in a collisionless, supersonic plasma was investigated in laboratory experiments. The experimental conditions address both single ion and binary ion plasma flows for the case of a body whose size is large in comparison with the Debye length, when the potential difference between the body and the plasma is relatively small. A new plasma source was developed to generate equi-velocity, binary ion plasma flows, which allows access to new parameter space that have previously been unavailable for laboratory studies. Specifically, the new parameters are the ionic mass ratio and the ionic component density ratio. In a series of experiments, a krypton-neon plasma is employed where the ambient density ratio of neon to krypton is varied more than an order of magnitude. The expansion in both the single ion and binary ion plasma cases is limited to early times, i.e., a few ion plasma periods, by the combination of plasma density, plasma drift speed, and vacuum chamber size, which prevented detailed comparison with self-similar theory.

  1. Cold atmospheric pressure air plasma jet for medical applications

    SciTech Connect

    Kolb, J. F.; Price, R. O.; Bowman, A.; Chiavarini, R. L.; Stacey, M.; Schoenbach, K. H.; Mohamed, A.-A H.; Swanson, R. J.

    2008-06-16

    By flowing atmospheric pressure air through a direct current powered microhollow cathode discharge, we were able to generate a 2 cm long plasma jet. With increasing flow rate, the flow becomes turbulent and temperatures of the jet are reduced to values close to room temperature. Utilizing the jet, yeast grown on agar can be eradicated with a treatment of only a few seconds. Conversely, animal studies show no skin damage even with exposures ten times longer than needed for pathogen extermination. This cold plasma jet provides an effective mode of treatment for yeast infections of the skin.

  2. Cold atmospheric pressure air plasma jet for medical applications

    NASA Astrophysics Data System (ADS)

    Kolb, J. F.; Mohamed, A.-A. H.; Price, R. O.; Swanson, R. J.; Bowman, A.; Chiavarini, R. L.; Stacey, M.; Schoenbach, K. H.

    2008-06-01

    By flowing atmospheric pressure air through a direct current powered microhollow cathode discharge, we were able to generate a 2cm long plasma jet. With increasing flow rate, the flow becomes turbulent and temperatures of the jet are reduced to values close to room temperature. Utilizing the jet, yeast grown on agar can be eradicated with a treatment of only a few seconds. Conversely, animal studies show no skin damage even with exposures ten times longer than needed for pathogen extermination. This cold plasma jet provides an effective mode of treatment for yeast infections of the skin.

  3. Application of dust grains and Langmuir probe for plasma diagnostics

    NASA Astrophysics Data System (ADS)

    Ussenov, Y. A.; Ramazanov, T. S.; Dzhumagulova, K. N.; Dosbolayev, M. K.

    2014-01-01

    This paper presents the results of the analysis of the experimentally measured width of the dust-free region around a single electric probe in a dusty plasma of glow discharge. The experimental results were compared with the data of a theoretical study on the basis of the balance equation of the dust particles thermal energy and their electrostatic interaction energy with the probe. An alternative method for the determination of the buffer plasma parameters was developed by measuring the dust-free region area around the probe. Using this method the temperature and the concentration of electrons in an argon glow discharge plasma in the pressure range from P= 0.6 to P= 0.8\\ \\text{torr} were determined.

  4. Experimental study of microwave transmission through a decaying plasma. Final report, January 1986-February 1988

    SciTech Connect

    Hendricks, K.J.

    1989-05-01

    The physics of pulsed-microwave, or radio-frequency (r-f), transmission through a decaying plasma column, is studied experimentally. A plasma column is formed in argon or nitrogen gases, to represent the neutral-gas breakdown due to an rf pulse. Initially, the electron frequency is greater than the microwave frequency. An r-f pulse capable of plasma reionization is applied across the plasma column at varying times in the plasma's decay phase (the plasma afterglow). Variation of the transmitted rf pulse characteristics, pulse width, and amplitude was studied as a function of the time into the afterglow. The ionization frequency of argon by a microwave pulse is found experimentally to be within 20% of the theoretical value. The comparison of ionization frequency is useful in establishing the applicability of earlier cavity measurements to present-day open-geometry systems used in transmission/propagation experiments.

  5. Status of Plasma Electron Hose Instability Studies in FACET

    SciTech Connect

    Adli, Erik; England, Robert Joel; Frederico, Joel; Hogan, Mark; Li, Selina Zhao; Litos, Michael Dennis; Nosochkov, Yuri; An, Weiming; Mori, Warren; /UCLA

    2011-12-13

    In the FACET plasma-wakefield acceleration experiment a dense 23 GeV electron beam will interact with lithium and cesium plasmas, leading to plasma ion-channel formation. The interaction between the electron beam and the plasma sheath-electrons may lead to a fast growing electron hose instability. By using optics dispersion knobs to induce a controlled z-x tilt along the beam entering the plasma, we investigate the transverse behavior of the beam in the plasma as function of the tilt. We seek to quantify limits on the instability in order to further explore potential limitations on future plasma wakefield accelerators due to the electron hose instability. The FACET plasma-wakefield experiment at SLAC will study beam driven plasma wakefield acceleration. A dense 23 GeV electron beam will interact with lithium or cesium plasma, leading to plasma ion-channel formation. The interaction between the electron beam and the plasma sheath-electrons drives the electron hose instability, as first studied by Whittum. While Ref. [2] indicates the possibility of a large instability growth rate for typical beam and plasma parameters, other studies including have shown that several physical effects may mitigate the hosing growth rate substantially. So far there has been no quantitative benchmarking of experimentally observed hosing in previous experiments. At FACET we aim to perform such benchmarking by for example inducing a controlled z-x tilt along the beamentering the plasma, and observing the transverse behavior of the beam in the plasma as function. The long-term objective of these studies is to quantify potential limitations on future plasma wakefield accelerators due to the electron hose instability.

  6. Dust-Plasma

    SciTech Connect

    Marelene Rosenberg

    2005-02-22

    Our theoretical research on dust-plasma interactions has concentrated on three main areas: a)studies of grain charging and applications; b) waves and instabilities in weakly correlated dusty plasma with applications to space and laboratory plasmas; c) waves in strongly coupled dusty plasmas.

  7. [Inductively coupled plasma and clinical biology. Toxicological applications].

    PubMed

    Goullé, J-P; Mahieu, L; Lainé, G; Lacroix, C; Clarot, F; Vaz, E; Proust, B

    2004-09-01

    The multi-elementary quantitation method using inductively coupled plasma mass spectrometry has been widely developed for use with biological fluids. Many elements can be quantified simultaneously in biological fluids, including: Li, Be, B, Al, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Rb, Sr, Mo, Pd, Cd, Sn, Sb, Te, Ba, W, Pt, Hg, Tl, Pb, Bi, U. The validation procedure is described by the French Society of Clinical Biology. Results for urine are corrected after creatinine determination. We report applications in clinical toxicology and forensic toxicology. Advances in inductively coupled plasma mass spectrometry in the field of clinical biology are particularly important for toxicological analysis. This powerful tool is helpful for better patient care and for the search for cause of death.

  8. M3D project for simulation studies of plasmas

    SciTech Connect

    Park, W.; Belova, E.V.; Fu, G.Y.; Strauss, H.R.; Sugiyama, L.E.

    1998-12-31

    The M3D (Multi-level 3D) project carries out simulation studies of plasmas of various regimes using multi-levels of physics, geometry, and mesh schemes in one code package. This paper and papers by Strauss, Sugiyama, and Belova in this workshop describe the project, and present examples of current applications. The currently available physics models of the M3D project are MHD, two-fluids, gyrokinetic hot particle/MHD hybrid, and gyrokinetic particle ion/two-fluid hybrid models. The code can be run with both structured and unstructured meshes.

  9. Theoretical studies on plasma heating and confinement

    SciTech Connect

    Sudan, R.N.

    1993-01-01

    Three principal topics are covered in this final report: Stabilization of low frequency modes of an axisymmetric compact torus plasma confinement system, such as, spheromaks and FRC'S, by a population of large orbit axis encircling energetic ions. Employing an extension of the energy principle' which utilizes a Vlasov description for the energetic 'ion component, it has been demonstrated that short wavelength MHD type modes are stabilized while the long wavelength tilt and precessional modes are marginally stable. The deformation of the equilibrium configuration by the energetic ions results in the stabilization of the tilt mode for spheromaks. Formation of Ion Rings and their coalescence with spheromaks. A two dimensional electromagnetic PIC codes has been developed for the study of ion ring formation and its propagation, deformation and slowing down in a cold plasma. It has been shown that a ring moving at a speed less than the Alfven velocity can merge with a stationary spheromak. Anomalous transport from drift waves in a Tokomak. The Direct Interaction Approximation in used to obtain incremental transport coefficients for particles and heat for drift waves in a Tokomak. It is shown that the transport matrix does not obey Onsager's principle.

  10. Automated Plasma Spray (APS) process feasibility study

    NASA Technical Reports Server (NTRS)

    Fetheroff, C. W.; Derkacs, T.; Matay, I. M.

    1981-01-01

    An automated plasma spray (APS) process was developed to apply two layer (NiCrAlY and ZrO2-12Y2O3) thermal barrier coatings to aircraft and stationary gas turbine engine blade airfoils. The APS process hardware consists of four subsystems: a mechanical positioning subsystem incorporating two interlaced six degree of freedom assemblies (one for coating deposition and one for coating thickness monitoring); a noncoherent optical metrology subsystem (for in process gaging of the coating thickness buildup at specified points on the specimen); a microprocessor based adaptive system controller (to achieve the desired overall thickness profile on the specimen); and commerical plasma spray equipment. Over fifty JT9D first stage aircraft turbine blade specimens, ten W501B utility turbine blade specimens and dozens of cylindrical specimens were coated with the APS process in preliminary checkout and evaluation studies. The best of the preliminary turbine blade specimens achieved an overall coating thickness uniformity of 53 micrometers (2.1 mils), much better than is achievable manually. Comparative evaluations of coating thickness uniformity for manually sprayed and APS coated specimens were performed. One of the preliminary turbine blade evaluation specimens was subjected to a torch test and metallographic evaluation. Some cylindrical specimens coated with the APS process survived up to 2000 cycles in subsequent burner rig testing.

  11. Plasma-generated reactive oxygen species for biomedical applications

    NASA Astrophysics Data System (ADS)

    Sousa, J. S.; Hammer, M. U.; Winter, J.; Tresp, H.; Duennbier, M.; Iseni, S.; Martin, V.; Puech, V.; Weltmann, K. D.; Reuter, S.

    2012-10-01

    To get a better insight into the effects of reactive oxygen species (ROS) on cellular components, fundamental studies are essential to determine the nature and concentration of plasma-generated ROS, and the chemistry induced in biological liquids by those ROS. In this context, we have measured the absolute density of the main ROS created in three different atmospheric pressure plasma sources: two geometrically distinct RF-driven microplasma jets (μ-APPJ [1] and kinpen [2]), and an array of microcathode sustained discharges [3]. Optical diagnostics of the plasma volumes and effluent regions have been performed: UV absorption for O3 and IR emission for O2(a^1δ) [4]. High concentrations of both ROS have been obtained (10^14--10^17cm-3). The effect of different parameters, such as gas flows and mixtures and power coupled to the plasmas, has been studied. For plasma biomedicine, the determination of the reactive species present in plasma-treated liquids is of great importance. In this work, we focused on the measurement of the concentration of H2O2 and NOX radicals, generated in physiological solutions like NaCl and PBS.[4pt] [1] N. Knake et al., J. Phys. D: App. Phys. 41, 194006 (2008)[0pt] [2] K.D. Weltmann et al., Pure Appl. Chem. 82, 1223 (2010)[0pt] [3] J.S. Sousa et al., Appl. Phys. Lett. 97, 141502 (2010)[0pt] [4] J.S. Sousa et al., Appl. Phys. Lett. 93, 011502 (2008)

  12. EXPERIMENTAL STUDY OF SHOCK WAVE DYNAMICS IN MAGNETIZED PLASMAS

    SciTech Connect

    Nirmol K. Podder

    2009-03-17

    In this four-year project (including one-year extension), the project director and his research team built a shock-wave-plasma apparatus to study shock wave dynamics in glow discharge plasmas in nitrogen and argon at medium pressure (1–20 Torr), carried out various plasma and shock diagnostics and measurements that lead to increased understanding of the shock wave acceleration phenomena in plasmas. The measurements clearly show that in the steady-state dc glow discharge plasma, at fixed gas pressure the shock wave velocity increases, its amplitude decreases, and the shock wave disperses non-linearly as a function of the plasma current. In the pulsed discharge plasma, at fixed gas pressure the shock wave dispersion width and velocity increase as a function of the delay between the switch-on of the plasma and shock-launch. In the afterglow plasma, at fixed gas pressure the shock wave dispersion width and velocity decrease as a function of the delay between the plasma switch-off and shock-launch. These changes are found to be opposite and reversing towards the room temperature value which is the initial condition for plasma ignition case. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas.

  13. Investigation of antibacterial and wettability behaviours of plasma-modified PMMA films for application in ophthalmology

    NASA Astrophysics Data System (ADS)

    Rezaei, Fatemeh; Abbasi-Firouzjah, Marzieh; Shokri, Babak

    2014-02-01

    The main objective of this research is the experimental investigation of the surface properties of polymethyl methacrylate (PMMA) such as wettability and the roughness effect on Escherichia coli (gram negative) cell adhesion. Radio frequency (RF; 13.56 MHz) oxygen plasma was used to enhance the antibacterial and wettability properties of this polymer for biomedical applications, especially ophthalmology. The surface was activated by O2 plasma to produce hydrophilic functional groups. Samples were treated with various RF powers from 10 to 80 W and different gas flow rates from 20 to 120 sccm. Optical emission spectroscopy was used to monitor the plasma process. The modified surface hydrophilicity, morphology and transparency characteristics were studied by water contact angle measurements, atomic force microscopy and UV-vis spectroscopy, respectively. Based on the contact angle measurements of three liquids, surface free energy variations were investigated. Moreover, the antibacterial properties were evaluated utilizing the method of plate counting of Escherichia coli. Also, in order to investigate stability of the plasma treatment, an ageing study was carried out by water contact angle measurements repeated in the days after the treatment. For biomedical applications, especially eye lenses, highly efficient antibacterial surfaces with appropriate hydrophilicity and transparency are of great importance. In this study, it is shown that the plasma process is a reliable and convenient method to achieve these purposes. A significant alteration in the hydrophilicity of a pristine PMMA surface was observed after treatment. Also, our results indicated that the plasma-modified PMMAs exhibit appropriate antibacterial performance. Moreover, surface hydrophilicity and surface charge have more influence on bacterial adhesion rate than surface roughness. UV-vis analysis results do not show a considerable difference for transparency of samples after plasma treatment.

  14. Hybrid Modeling of Plasmas and Applications to Fusion and Space Physics.

    NASA Astrophysics Data System (ADS)

    Kazeminejad, Farzad

    Since the early days of controlled fusion research, plasma physicists have encountered great challenges in obtaining solutions to the highly nonlinear equations which govern the behavior of fusion plasmas; with the growth of other applications of plasma physics (space plasmas, plasma accelerators, ... etc.) these problems have grown in importance. Obtaining reasonable solutions to the nonlinear equations is crucial to our understanding of the behavior of plasmas. With the advent of high speed computers, computer modeling of plasmas has moved into the front row of the tools used in research of their nonlinear plasma dynamics. There are roughly speaking two types of plasma models, particle models and fluid models. Particle models try to emulate nature by following the motion of a large number of charged particles in their self consistent electromagnetic fields. Fluid models on the other hand use macroscopic fluid equations to model the plasma. MHD models are typical of this type. Particle models in general require larger memory for the computer due to the massive amounts of data associated with the particles' kinematical variables. Particle models are generally limited to studying small regions of plasma for relatively short time intervals. Fluid models are better fit to handle large scales and long times; i.e., quite often the complete plasma involved in an experiment. The drawback of the fluid models however is that, they miss the physical phenomenon taking place at the microscale and these phenomenon can influence the properties of fluid; i.e., its resistivity, viscosity, heat transport, etc. One can attempt to put these effects in as phenomenological coefficients, but such approaches are always somewhat ad hoc. Another approach is to start with fluid models and incorporate more physics. Such models are referred to as hybrid models. In this thesis, two such models are discussed. They are then applied to two problems; the first is a simulation of the artificial

  15. A 1D (radial) Plasma Jet Propagation Study for the Plasma Liner Experiment (PLX)

    NASA Astrophysics Data System (ADS)

    Thompson, J. R.; Bogatu, I. N.; Galkin, S. A.; Kim, J. S.; Welch, D. R.; Thoma, C.; Golovkin, I.; Macfarlane, J. J.; Case, A.; Messer, S. J.; Witherspoon, F. D.; Cassibry, J. T.; Awe, T. J.; Hsu, S. C.

    2011-10-01

    The Plasma Liner Experiment will explore the formation of imploding spherical ``plasma liners'' that reach peak pressures of 0.1 Mbar upon stagnation. The liners will be formed through the merging of dense, high velocity plasma jets (n ~1017 cm-3, T ~3 eV, v ~50 km/s) in a spherically convergent geometry. The focus of this 1D (radial) study is argon plasma jet evolution during propagation from the rail gun source to the jet merging radius. The study utilizes the Large Scale Plasma (LSP) PIC code with atomic physics included through the use of a non-Local Thermal Equilibrium (NLTE) Equation of State (EOS) table. We will present scenarios for expected 1D (radial) plasma jet evolution, from upon exiting the PLX rail gun to reaching the jet merging radius. The importance of radiation cooling early in the simulation is highlighted. Work supported by US DOE grant DE-FG02-05ER54835.

  16. Studies on plasma processing of blue dust

    NASA Astrophysics Data System (ADS)

    Samal, S. K.; P, Sindhoora L.; Mishra, S. C.; Mishra, B.

    2015-02-01

    Plasma smelting was carried out using blue dust and petroleum coke mixtures for five different compositions. By altering percentage of reductant and type of plasma forming gas, recovery rate and degree of metallization were calculated in order to examine the extent of reduction of blue dust. The products were characterized by XRD and optical microscopy techniques. The results of these investigations exhibited that highest degree of metallization and recovery rate of about 98% and 86% respectively, were achieved for nitrogen plasma smelted products.

  17. Plasma Synthesis of Nanoparticles for Nanocomposite Energy Applications

    SciTech Connect

    Peter C. Kong; Alex W. Kawczak

    2008-09-01

    The nanocomposite energy applications for plasma reactor produced nanoparticles are reviewed. Nanoparticles are commonly defined as particles less than 100 nm in diameter. Due to this small size, nanoparticles have a high surface-to-volume ratio. This increases the surface energy compared to the bulk material. The high surface-to-volume ratio and size effects (quantum effects) give nanoparticles distinctive chemical, electronic, optical, magnetic and mechanical properties from those of the bulk material. Nanoparticles synthesis can be grouped into 3 broad approaches. The first one is wet phase synthesis (sol-gel processing), the second is mechanical attrition, and the third is gas-phase synthesis (aerosol). The properties of the final product may differ significantly depending on the fabrication route. Currently, there are no economical large-scale production processes for nanoparticles. This hinders the widespread applications of nanomaterials in products. The Idaho National Laboratory (INL) is engaging in research and development of advanced modular hybrid plasma reactors for low cost production of nanoparticles that is predicted to accelerate application research and enable the formation of technology innovation alliances that will result in the commercial production of nanocomposites for alternative energy production devices such as fuel cells, photovoltaics and electrochemical double layer capacitors.

  18. PLASIMO model of micro-plasma jet for biomedical applications

    NASA Astrophysics Data System (ADS)

    Mihailova, Diana; Sobota, Ana; Graef, Wouter; van Dijk, Jan; Hagelaar, Gerjan

    2014-10-01

    Non-equilibrium atmospheric pressure micro-plasma jets are widely studied for use in biotechnology, including treatment of human tissue. The setup under study consists of capillary powered electrode through which helium gas flows and a grounded ring electrode placed a distance of few mm in front of the capillary. The discharge is excited by sinusoidal voltage with amplitude of 2 kV and 30 KHz repetition rate. The plume emanating from the jet, or the plasma bullets, propagates through a Pyrex tube and the gas phase channel of helium into the surrounding air.aim of this work is to get insight into the plasma constituents that can affect directly or indirectly living tissue. This includes radicals (OH, NO, O,), ions and electrons, UV radiation, electrical fields. PLASIMO modelling toolkit is used to simulate the capillary plasma-jet in order to quantify the delivery of fluxes and fields to the treated tissue. Verification is made by comparing results obtained with the PLASIMO and MAGMA codes (developed at LAPLACE, Toulouse) for the same input specifications. Both models are validated by comparison with experimental observations at various operating parameters.

  19. Simulation of magnetohydrodynamics turbulence with application to plasma-assisted supersonic combustion

    NASA Astrophysics Data System (ADS)

    Miki, Kenji

    Plasma assisted combustion (PAC) is a promising alternative to hold or ignite a fuel and air mixture in a supersonic environment. Efficient supersonic combustion is of primary importance for SCRAMJET technology. The advantages of PAC is the addition of large amounts of energy to specific regions of the SCRAMJET flow-field for short periods of time, and as a result accelerate the fuel/air kinetic rates to achieve a self-sustaining condition. Moreover, the promise of enhancement of fuel-air mixing by magnetohydrodynamics (MHD) flow control offers significant improvement of combustion performance. The development of a numerical tool for investigating high-temperature chemistry and plasmadynamic effects of a discharge arc is desired to gain understanding of PAC technology and the potential improvement of the operational efficiency of SCRAMJET engines. The main objective of this research is to develop a comprehensive model with the capability of modeling both high Reynolds number and high magnetic Reynolds number turbulent flow for application to supersonic combustor. The development of this model can be divided into three categories: first, the development of a self-consistent MHD numerical model capable of modeling magnetic turbulence in high magnetic Reynolds number applications. Second, the development of a gas discharge model which models the interaction of externally applied fields in conductive medium. Third, the development of models necessary for studying supersonic combustion applications with plasma-assistance such the extension of chemical kinetics models to extremely high temperature and non-equilibrium phenomenon. Finally, these models are combined and utilized to model plasma assisted combustion in a SCRAMJET. Two types of plasmas are investigated: an equilibrium electrical discharge (arc) and a non-equilibrium plasma jet. It is shown that both plasmas significantly increase the concentration of radicals such as O, OH and H, and both have positive impact

  20. A slotted waveguide field applicator to sustain large diameter uniform plasma cylinders.

    PubMed

    Wu, C; Zhan, R; Huang, W

    2000-01-01

    We describe a slotted waveguide field applicator and present the results of experimental investigation. The experimental results show that it can efficiently transfer power to plasma in the wide pressure range. Specially, it is able to produce a large diameter uniform plasma cylinder with diameter over 160 mm. The electron temperature and density are 2-4 eV and 10(10)-10(11) cm-3, respectively, under conditions of the pressure below 135 Pa and the microwave power 500-900 w. In addition, the primary study of the surface-wave modes indicate that the mode of m = 6 can be excited and propagate.

  1. Development and Validation of an HPLC Method for Simultaneous Quantification of Clopidogrel Bisulfate, Its Carboxylic Acid Metabolite, and Atorvastatin in Human Plasma: Application to a Pharmacokinetic Study

    PubMed Central

    Croitoru, Octavian; Spiridon, Adela-Maria; Belu, Ionela; Turcu-Ştiolică, Adina; Neamţu, Johny

    2015-01-01

    A simple, sensitive, and specific reversed phase liquid chromatographic method was developed and validated for simultaneous quantification of clopidogrel, its carboxylic acid metabolite, and atorvastatin in human serum. Plasma samples were deproteinized with acetonitrile and ibuprofen was chosen as internal standard. Chromatographic separation was performed on an BDS Hypersil C18 column (250 × 4.6 mm; 5 μm) via gradient elution with mobile phase consisting of 10 mM phosphoric acid (sodium) buffer solution (pH = 2.6 adjusted with 85% orthophosphoric acid) : acetonitrile : methanol with flow rate of 1 mL·min−1. Detection was achieved with PDA detector at 220 nm. The method was validated in terms of linearity, sensitivity, precision, accuracy, limit of quantification, and stability tests. Calibration curves of the analytes were found to be linear in the range of 0.008–2 μg·mL−1 for clopidogrel, 0.01–4 μg·mL−1 for its carboxylic acid metabolite, and 0.005–2.5 μg·mL−1 for atorvastatin. The results of accuracy (as recovery) with ibuprofen as internal standard were in the range of 96–98% for clopidogrel, 94–98% for its carboxylic acid metabolite, and 90–99% for atorvastatin, respectively. PMID:26839733

  2. Development and Validation of an HPLC Method for Simultaneous Quantification of Clopidogrel Bisulfate, Its Carboxylic Acid Metabolite, and Atorvastatin in Human Plasma: Application to a Pharmacokinetic Study.

    PubMed

    Croitoru, Octavian; Spiridon, Adela-Maria; Belu, Ionela; Turcu-Ştiolică, Adina; Neamţu, Johny

    2015-01-01

    A simple, sensitive, and specific reversed phase liquid chromatographic method was developed and validated for simultaneous quantification of clopidogrel, its carboxylic acid metabolite, and atorvastatin in human serum. Plasma samples were deproteinized with acetonitrile and ibuprofen was chosen as internal standard. Chromatographic separation was performed on an BDS Hypersil C18 column (250 × 4.6 mm; 5 μm) via gradient elution with mobile phase consisting of 10 mM phosphoric acid (sodium) buffer solution (pH = 2.6 adjusted with 85% orthophosphoric acid) : acetonitrile : methanol with flow rate of 1 mL·min(-1). Detection was achieved with PDA detector at 220 nm. The method was validated in terms of linearity, sensitivity, precision, accuracy, limit of quantification, and stability tests. Calibration curves of the analytes were found to be linear in the range of 0.008-2 μg·mL(-1) for clopidogrel, 0.01-4 μg·mL(-1) for its carboxylic acid metabolite, and 0.005-2.5 μg·mL(-1) for atorvastatin. The results of accuracy (as recovery) with ibuprofen as internal standard were in the range of 96-98% for clopidogrel, 94-98% for its carboxylic acid metabolite, and 90-99% for atorvastatin, respectively. PMID:26839733

  3. Numerical Studies of Electrode Plasma Formation and Expansion in High Power Charged Particle Beam Diodes

    NASA Astrophysics Data System (ADS)

    Rittersdorf, I. M.; Swanekamp, S. B.; Richardson, A. S.; Allen, R. J.; Schumer, J. W.

    2014-10-01

    High-power diodes that generate intense electron beams are useful in many applications, such as producing x-rays for flash radiography and nuclear weapon effects simulations. Desorption and ionization of gases from electrodes can form a plasma during operation. Expansion of this plasma into the gap leads to a short circuit, which limits the radiation production. It is difficult for particle-in-cell codes to model the surface physics or the subsequent expansion of the plasma. NRL is beginning a multi-year research effort to study such plasmas. This paper will summarize the relevant literature on plasma formation in high-power diodes with a goal of developing dynamic models that describe the formation and expansion of these plasmas that are suitable for PIC codes. This work was supported by the NRL Basic and Applied Research Program.

  4. Center for the Study of Plasma Microturbulence

    SciTech Connect

    Parker, Scott E.

    2012-03-02

    We have discovered a possible "natural fueling" mechanism in tokamak fusion reactors using large scale gyrokinetic turbulence simulation. In the presence of a heat flux dominated tokamak plasma, cold ions naturally pinch radially inward. If cold DT fuel is introduced near the edge using shallow pellet injection, the cold fuel will pinch inward, at the expense of hot helium ash going radially outward. By adjusting the cold DT fuel concentration, the core DT density profiles can be maintained. We have also shown that cold source ions from edge recycling of cold neutrals are pinched radially inward. This mechanism may be important for fully understanding the edge pedestal buildup after an ELM crash. Work includes benchmarking the gyrokinetic turbulence codes in the electromagnetic regime. This includes cyclone base case parameters with an increasing plasma beta. The code comparisons include GEM, GYRO and GENE. There is good linear agreement between the codes using the Cyclone base case, but including electromagnetics and scanning the plasma beta. All the codes have difficulty achieving nonlinear saturation as the kinetic ballooning limit is approached. GEM does not saturate well when beta gets above about 1/2 of the ideal ballooning limit. We find that the lack of saturation is due to the long wavelength k{sub y} modes being nonlinearly pumped to high levels. If the fundamental k{sub y} mode is zeroed out, higher values of beta nonlinearly saturate well. Additionally, there have been studies to better understand CTEM nonlinear saturation and the importance of zonal flows. We have continued our investigation of trapped electron mode (TEM) turbulence. More recently, we have focused on the nonlinear saturation of TEM turbulence. An important feature of TEM is that in many parameter regimes, the zonal flow is unimportant. We find that when zonal flows are unimportant, zonal density is the dominant saturation mechanism. We developed a simple theory that agrees with the

  5. Multi-electrodes Atmospheric Pressure Plasma Jet Aiming Bio-applications

    NASA Astrophysics Data System (ADS)

    Han, Jeon G.; Sahu, B. B.; Shin, K. S.; Lee, J. S.; Hori, M.

    2015-09-01

    For the recent advancement in the field of plasma medicine, there is growing demand for the atmospheric-pressure plasma (APP) jet sources with desired plasma characteristics. In this study, a stable non-thermal low-voltage APP jet device was designed and developed for optical and electrical characterizations. The jet was operated at very low frequency in the range 10-40 KHz, which enabled the generation of low power (~ 7W) plasma with a plasma column diameter of about 5 mm. The jet has a visible radial diameter of approximately 10 mm. Optical emission spectroscopy was used as a diagnostic tool to investigate the generation of plasmas and radical species. Discharge parameters are also measured to evaluate the different operating conditions. The gas temperature measured at the substrate location varies from 300 to 315 K for different gases where the electrical input power ranged from 1 to 7 W. The highly reactive species like OH, O, N2, N2 + and along with the trace of NO are characterized with respect to the different gas flow rate of Ar/He/O2/N2, applied voltages, duty cycles and frequencies to evaluate the capability of the APP jet for future bio-applications.

  6. Application of atmospheric plasma sources in growth and differentiation of plant and mammalian stem cells

    NASA Astrophysics Data System (ADS)

    Puac, Nevena

    2014-10-01

    The expansion of the plasma medicine and its demand for in-vivo treatments resulted in fast development of various plasma devices that operate at atmospheric pressure. These sources have to fulfill all demands for application on biological samples. One of the sources that meet all the requirements needed for treatment of biological material is plasma needle. Previously, we have used this device for sterilization of planctonic samples of bacteria, MRSA biofilm, for improved differentiation of human periodontal stem cells into osteogenic line and for treatment of plant meristematic cells. It is well known that plasma generates reactive oxygen species (ROS) and reactive nitrogen species (RNS) that strongly affect metabolism of living cells. One of the open issues is to correlate external plasma products (electrons, ions, RNS, ROS, photons, strong fields etc.) with the immediate internal response which triggers or induces effects in the living cell. For that purpose we have studied the kinetics of enzymes which are typical indicators of the identity of reactive species from the plasma created environment that can trigger signal transduction in the cell and ensue cell activity. In collaboration with Suzana Zivkovicm, Institute for Biological Research ``Sinisa Stankovic,'' University of Belgrade; Nenad Selakovic, Institute of Physics, University of Belgrade; Milica Milutinovic, Jelena Boljevic, Institute for Biological Research ``Sinisa Stankovic,'' University of Belgrade; and Gordana Malovic, Zoran Lj. Petrovic, Institute of Physics, University of Belgrade. Grants III41011, ON171037 and ON173024, MESTD, Serbia.

  7. Observation of Hypervelocity Dust in Dense Supersonic Plasma Flows: Physics and Applications

    SciTech Connect

    Ticos, C. M.; Wang, Z.; Wurden, G. A.; Shukla, P. K.

    2008-10-15

    Synthetic diamond and graphite dust powders with a wide range of sizes, from a few to several tens of microns in diameter were accelerated to velocities up to 4 km/s in vacuum by plasma jet produced in a coaxial gun. Some of the key features of the plasma flow are high density, of the order of 10{sup 22} m{sup -3}, low ion and electron temperatures, of only a few eV, and good collimation over a distance of {approx_equal}2 m due to confinement by the self-generated magnetic field. The main features of this plasma-drag acceleration technique are presented and discussed. From basic science point of view hypervelocity dust is useful for studying the physics of dust interaction with energetic plasma flows at microscopic level. In physical applications, it has been proposed to use hypervelocity dust for diagnostic or control of magnetically confined fusion plasmas. In engineering, hypervelocity dusty plasmas are extensively employed in industrial processes involved in the processing of surfaces.

  8. High speed cine film studies of plasma behaviour and plasma surface interactions in tokamaks

    NASA Astrophysics Data System (ADS)

    Goodall, D. H. J.

    1982-12-01

    High speed cine photography is a useful diagnostic aid for studying plasma behaviour and plasma surface interactions. Several workers have filmed discharges in tokamaks including ASDEX, DITE, DIVA, ISX, JFT2, TFR and PLT. These films are discussed and examples given of the observed phenomena which include plasma limiter interactions, diverted discharges, disruptions, magnetic islands and moving glowing objects often known as 'UFOs'. Examples of plasma structures in ASDEX and DITE not previously published are also given. The paper also reports experiments in DITE to determine the origin of UFOs.

  9. Simultaneous quantification of cefpodoxime proxetil and clavulanic acid in human plasma by LC-MS using solid phase extraction with application to pharmacokinetic studies.

    PubMed

    Dubala, Anil; Nagarajan, Janaki Sankarachari Krishnan; Vimal, Chandran Sathish; George, Renjith

    2013-03-15

    A simple, rapid and selective high performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLC-APCI-MS) method was developed and validated for the simultaneous estimation of cefpodoxime proxetil (CDPX) and clavulanic acid (CA) in human plasma. Extraction of samples was done by solid phase extraction technique (SPE) and chloramphenicol used as internal standard. Chromatographic separation was carried out on a reverse phase Princeton SPHER C18 (150mm×4mm i.d., 5μm) column using mixture of methanol: acetonitrile: 2mM ammonium acetate (25:25:50, v/v, pH 3.5) at 0.8mL/min flow rate. Detection was performed on a single quadrupole MS by selected ion monitoring (SIM) mode via APCI source. The calibration curve was linear within the concentration range, 0.04-4.4μg/mL and 0.1-10.0μg/mL for CDPX and CA respectively. Pharmacokinetic parameters of tablet (CDPX 200mg, CA 125mg) were evaluated. Cmax, Tmax, T1/2, elimination rate constant (Kel), AUC0-t, and AUC0-∞ of tablet were 2.13±0.06μg/mL, 2h, 3.05±0.15h, 0.24±0.37h(-1), 6.81±0.14μg h/mL and 7.72±0.23μg h/mL respectively for cefpodoxime (CP), 5.34±0.28μg/mL, 2h, 2.73±0.25h, 0.26±0.31h(-1), 15.37±0.16μg h/mL and 16.59±0.53μg h/mL respectively for CA.

  10. Development and Validation of an LC-MS-MS Method for Determination of Simvastatin and Simvastatin Acid in Human Plasma: Application to a Pharmacokinetic Study.

    PubMed

    Partani, Pankaj; Verma, Saurabh Manaswita; Monif, Tausif

    2016-09-01

    A liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of simvastatin (SV) and simvastatin acid (SVA) in human plasma. To improve assay sensitivity and achieve simultaneous analysis, SVA monitored in (-)ESI (electrospray ionization) mode within the first 4.5 min and SV thereafter in (+)ESI mode. The separation of all compounds was achieved in about 6.2 min using a C18 reverse-phase fused-core(®) column (Ascentis(®) Express C18) and a mobile phase, which was composed of 2.00 ± 0.05 mM ammonium acetate buffer titrated to pH 3.8 with glacial acetic acid-acetonitrile (25:75, v/v), in isocratic mode at a flow rate of 0.500 mL/min. Additionally, a solid-phase extraction step was performed to reduce any ion-suppression and/or enhancement effects. The developed method was linear in the concentration range of 0.100-74.626 ng/mL for SV, and 0.100-48.971 ng/mL for SVA, with correlation coefficient greater than 0.99 for both analytes. The method has shown tremendous reproducibility, with intra- and inter-day precision <7.6%, and intra- and interday accuracy within ±10.9% of nominal values, for the both analytes. The method was successfully applied to characterize the pharmacokinetic profiles of SV and SVA following an oral administration of 40 mg SV tablet to healthy human volunteers.

  11. Development and validation of a LC-MS/MS method for determination of pinoresinol diglucoside in rat plasma: Application to pharmacokinetic study.

    PubMed

    Song, Yanqing; Yan, Huiyu; Sun, Zhihui; Teng, Shiyong; Sun, Lirui; Zhang, Sixi

    2015-11-01

    Pinoresinol diglucoside (PD), a typical marker compound in Ecommia ulmoides Oliv., is an important and natural antihypertensive drug. A selective, sensitive, and rapid liquid chromatography tandem mass spectrometric (LC-MS/MS) analytical method was developed for the determination of PD in rats. After simple protein precipitation with acetonitrile, chromatographic separation of PD was conducted using a reversed-phase ZORBAX SB C18 analytical column (4.6mm × 150 mm, 5 μm particles) with a mobile phase of 10mM ammonium acetate-methanol-acetic acid (50:50:0.15, v/v/v) and quantified by selected reaction monitoring mode under positive electrospray ionization condition. The chromatographic run time was 3.4 min for each sample, in which the retention times of PD and the internal standard were 2.87 and 2.65 min, respectively. The calibration curves were linear over the range of 1.00~3000 ng/mL and the lower limit of quantification was 1.00 ng/mL in rat plasma. The precision expressed by relative standard deviations were <8.9% for intra-batch precision and <2.0% for inter-batch precision, and the intra- and inter-batch accuracy by relative error was within the range of -3.9% ~7.3%, which met acceptable criteria. The LC-MS/MS method was successfully applied to investigate the pharmacokinetics and oral bioavailability of PD in rats, with the bioavailability being only 2.5%.

  12. Novel 3D Tissue Engineered Bone Model, Biomimetic Nanomaterials, and Cold Atmospheric Plasma Technique for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Wang, Mian

    This thesis research is consist of four chapters, including biomimetic three-dimensional tissue engineered nanostructured bone model for breast cancer bone metastasis study (Chapter one), cold atmospheric plasma for selectively ablating metastatic breast cancer (Chapter two), design of biomimetic and bioactive cold plasma modified nanostructured scaffolds for enhanced osteogenic differentiation of bone marrow derived mesenchymal stem cells (Chapter three), and enhanced osteoblast and mesenchymal stem cell functions on titanium with hydrothermally treated nanocrystalline hydroxyapatite/magnetically treated carbon nanotubes for orthopedic applications (Chapter four). All the thesis research is focused on nanomaterials and the use of cold plasma technique for various biomedical applications.

  13. Atmospheric Pressure Plasma-Electrospin Hybrid Process for Protective Applications

    NASA Astrophysics Data System (ADS)

    Vitchuli Gangadharan, Narendiran

    2011-12-01

    Chemical and biological (C-B) warfare agents like sarin, sulfur mustard, anthrax are usually dispersed into atmosphere in the form of micro aerosols. They are considered to be dangerous weapon of mass destruction next to nuclear weapons. The airtight protective clothing materials currently available are able to stop the diffusion of threat agents but not good enough to detoxify them, which endangers the wearers. Extensive research efforts are being made to prepare advanced protective clothing materials that not only prevent the diffusion of C-B agents, but also detoxify them into harmless products thus ensuring the safety and comfort of the wearer. Electrospun nanofiber mats are considered to have effective filtration characteristics to stop the diffusion of submicron level particulates without sacrificing air permeability characteristics and could be used in protective application as barrier material. In addition, functional nanofibers could be potentially developed to detoxify the C-B warfare threats into harmless products. In this research, electrospun nanofibers were deposited on fabric surface to improve barrier efficiency without sacrificing comfort-related properties of the fabrics. Multi-functional nanofibers were fabricated through an electrospinning-electrospraying hybrid process and their ability to detoxify simulants of C-B agents was evaluated. Nanofibers were also deposited onto plasma-pretreated woven fabric substrate through a newly developed plasma-electrospinning hybrid process, to improve the adhesive properties of nanofibers on the fabric surface. The nanofiber adhesion and durability properties were evaluated by peel test, flex and abrasion resistance tests. In this research work, following tasks have been carried out: i) Controlled deposition of nanofiber mat onto woven fabric substrate Electrospun Nylon 6 fiber mats were deposited onto woven 50/50 Nylon/Cotton fabric with the motive of making them into protective material against submicron

  14. Atmospheric Pressure Plasma-Electrospin Hybrid Process for Protective Applications

    NASA Astrophysics Data System (ADS)

    Vitchuli Gangadharan, Narendiran

    2011-12-01

    Chemical and biological (C-B) warfare agents like sarin, sulfur mustard, anthrax are usually dispersed into atmosphere in the form of micro aerosols. They are considered to be dangerous weapon of mass destruction next to nuclear weapons. The airtight protective clothing materials currently available are able to stop the diffusion of threat agents but not good enough to detoxify them, which endangers the wearers. Extensive research efforts are being made to prepare advanced protective clothing materials that not only prevent the diffusion of C-B agents, but also detoxify them into harmless products thus ensuring the safety and comfort of the wearer. Electrospun nanofiber mats are considered to have effective filtration characteristics to stop the diffusion of submicron level particulates without sacrificing air permeability characteristics and could be used in protective application as barrier material. In addition, functional nanofibers could be potentially developed to detoxify the C-B warfare threats into harmless products. In this research, electrospun nanofibers were deposited on fabric surface to improve barrier efficiency without sacrificing comfort-related properties of the fabrics. Multi-functional nanofibers were fabricated through an electrospinning-electrospraying hybrid process and their ability to detoxify simulants of C-B agents was evaluated. Nanofibers were also deposited onto plasma-pretreated woven fabric substrate through a newly developed plasma-electrospinning hybrid process, to improve the adhesive properties of nanofibers on the fabric surface. The nanofiber adhesion and durability properties were evaluated by peel test, flex and abrasion resistance tests. In this research work, following tasks have been carried out: i) Controlled deposition of nanofiber mat onto woven fabric substrate Electrospun Nylon 6 fiber mats were deposited onto woven 50/50 Nylon/Cotton fabric with the motive of making them into protective material against submicron

  15. Studies on the effect of finite geometrical asymmetry in dual capacitively coupled radio frequency plasma

    NASA Astrophysics Data System (ADS)

    Bora, B.

    2015-10-01

    In recent years, dual capacitively coupled radio frequency (CCRF) glow discharge plasma has been widely studied in the laboratory because of its simpler design and high efficiency for different material processing applications such as thin-film deposition, plasma etching, sputtering of insulating materials etc. The main objective of studies on dual frequency CCRF plasma has been the independent control of ion energy and ion flux using an electrical asymmetry effect (EAE). Most studies have been reported in electrode configurations that are either geometrically symmetric (both electrodes are equal) or completely asymmetric (one electrode is infinitely bigger than the other). However, it seems that most of the laboratory CCRF plasmas have finite electrode geometry. In addition, plasma series resonance (PSR) and electron bounce resonance (EBR) heating also come into play as a result of geometrical asymmetry as well as EAE. In this study, a dual frequency CCRF plasma has been studied in which the dual frequency CCRF has been coupled to the lumped circuit model of the plasma and the time-independent fluid model of the plasma sheath, in order to study the effect of finite geometrical asymmetry on the generation of dc-self bias and plasma heating. The dc self-bias is found to strongly depend on the ratio of the area between the electrodes. The dc self-bias is found to depend on the phase angle between the two applied voltage waveforms. The EAE and geometrical asymmetry are found to work differently in controlling the dc self-bias. It can be concluded that the phase angle between the two voltage waveforms in dual CCRF plasmas has an important role in determining the dc self-bias and may be used for controlling the plasma properties in the dual frequency CCRF plasma.

  16. Determination of a novel anticancer c-Met inhibitor LS-177 in rat plasma and tissues with a validated UPLC-MS/MS method: application to pharmacokinetics and tissue distribution study.

    PubMed

    Ju, Ping; Liu, Zhenzhen; Jiang, Yu; Zhao, Simin; Zhang, Lunhui; Zhang, Yuanyuan; Gu, Liqiang; Tang, Xing; Bi, Kaishun; Chen, Xiaohui

    2015-07-01

    LS-177 is a novel small-molecule kinase inhibitor employed to interrupt the c-Met signaling pathway. A rapid and sensitive ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for determination of LS-177 in rat plasma and tissues. The biosamples were extracted by liquid-liquid extraction with methyl tert-butyl ether and separated on a C18 column (50 × 4.6 mm, 2.6 µm) using a gradient elution mobile phase consisting of acetonitrile-0.1% formic acid water. Under the optimal conditions, the selectivity of the method was satisfactory with no endogenous interference. The intraday and interday precisions (relative standard deviation) were <10.5% and the accuracy (relative error) was from -12.5 to 12.5% at all quality control levels. Excellent recovery and negligible matrix effects were observed. Stability studies showed that LS-177 was stable during the preparation and analytical processes. The UPLC-MS/MS method was successfully applied to pharmacokinetic and tissue distribution studies. The results indicated that there was no significant drug accumulation after multiple-dose oral administration of LS-177. The tissue distribution study exhibited significant higher uptakes of LS-177 in stomach, intestine, lung and liver among all of the tissues. The results in pharmacokinetics and tissue distribution may provide a meaningful basis for clinical application.

  17. Inductively coupled plasma mass spectrometry study of the retention behavior of arsenic species on various solid phase extraction cartridges and its application in arsenic speciation

    NASA Astrophysics Data System (ADS)

    Yu, Chunhai; Cai, Qiantao; Guo, Zhong-Xian; Yang, Zhaoguang; Khoo, Soo Beng

    2003-07-01

    Inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate the retention behavior of arsenite, arsenate, monomethylarsonic acid (MMA), dimethylarsinic acid (DMA), arsenobetaine (AsB), arsenocholine (AsC), trimethylarsine oxide (TMAO) and tetramethylarsonium ion (TMAI) on various silica-based solid phase extraction (SPE) cartridges. A method for arsenic speciation is then developed on the basis of selective SPE separation of arsenic species and highly sensitive ICP-MS detection. Factors affecting the retention and elution of arsenic species were examined. Results showed that the retention of arsenic species depended on the chemical characteristics of arsenic species and the types of sorbent materials. Change of pH in the range of 2.0-9.0 did not show significant effects on the retention of DMA, AsB, AsC, TMAI and TMAO on an ethylbenzene sulfonic acid-based strong cation exchange (SCX-3) cartridge. pH also did not influence the retention of AsB, AsC, TMAI and TMAO on a mixed-mode (M-M) cartridge containing non-polar, strong cation exchange and strong anion exchange (SAX) functional groups. However, the retentions of As(V) and MMA on the SAX and the M-M cartridge changed with pH. As(V) and MMA were completely retained on the SAX cartridge and sequentially selectively eluted with 1.0 mol l -1 acetic acid (for MMA). DMA, AsB, AsC, TMAI and TMAO were completely retained on the SCX-3 cartridge and sequentially selectively eluted with 1.0 mol l -1 HNO 3 (for DMA). As(V), MMA, AsB, AsC, TMAI and TMAO were completely retained on the M-M cartridge. As(III) was not retained on either cartridge and remained in solution. Arsenic species in solution and those eluted from the cartridges were subsequently determined by ICP-MS. A detection limit of 8 ng l -1 arsenic in water sample was obtained. This method was successfully applied to arsenic speciation in various sources of water samples (drinking water, waste water, raw water, etc.) and US National Institute of

  18. Application of electron beam plasma for biopolymers modification

    NASA Astrophysics Data System (ADS)

    Vasilieva, T. M.

    2012-06-01

    The effects of the Electron Beam Plasma treatment on natural polysaccharide chitosan were studied experimentally. Low molecular water-soluble products of chitosan and chitooligosaccharides were obtained by treating the original polymers in the Electron Beam Plasma of oxygen and water vapor. The molecular mass of the products varied from 18 kDa to monomeric fragments. The degradation of the original polymers was due to the action of active oxygen particles (atomic and singlet oxygen) and the particles of the water plasmolysis (hydroxyl radicals, hydrogen peroxides). The 95% yield of low molecular weight chitosans was attained by optimizing the treatment conditions. The studies of the antimicrobial activity of low molecular products showed that they strongly inhibit the multiplication of colon bacillus, aurococcus and yeast-like fungi. The EBP-stimulated degradation of polysaccharides and proteins were found to result from breaking β-1,4 glycosidic bounds and peptide bonds, respectively.

  19. The application of pulse modulated plasma to the plasma enhanced chemical vapor deposition of dielectric materials

    NASA Astrophysics Data System (ADS)

    Qi, Yu

    range of combinations of desired deposition qualities. Finally, the pulsed plasma was used to implement PECVD of teflon-like coatings. An important discovery in this application is that in addition to pulse period, on-time and on-time peak power, the power level during the off-time is an important factor. The density of CF2 is a function of all these pulse parameters. The best result obtained is up to 67.2% CF2 and a 1.87:1 of F:C ratio when the off-time power level is ˜100--130 W the frequency is several Hz, the on-time peak power is ˜1000 W and the duty ratio is ˜7--10%.

  20. Collisionless expansion of pulsed radio frequency plasmas. II. Parameter study

    NASA Astrophysics Data System (ADS)

    Schröder, T.; Grulke, O.; Klinger, T.; Boswell, R. W.; Charles, C.

    2016-01-01

    The plasma parameter dependencies of the dynamics during the expansion of plasma are studied with the use of a versatile particle-in-cell simulation tailored to a plasma expansion experiment [Schröder et al., J. Phys. D: Appl. Phys. 47, 055207 (2014); Schröder et al., Phys. Plasmas 23, 013511 (2016)]. The plasma expansion into a low-density ambient plasma features a propagating ion front that is preceding a density plateau. It has been shown that the front formation is entangled with a wave-breaking mechanism, i.e., an ion collapse [Sack and Schamel, Plasma Phys. Controlled Fusion 27, 717 (1985); Sack and Schamel, Phys. Lett. A 110, 206 (1985)], and the launch of an ion burst [Schröder et al., Phys. Plasmas 23, 013511 (2016)]. The systematic parameter study presented in this paper focuses on the influence on this mechanism its effect on the maximum velocity of the ion front and burst. It is shown that, apart from the well known dependency of the front propagation on the ion sound velocity, it also depends sensitively on the density ratio between main and ambient plasma density. The maximum ion velocity depends further on the initial potential gradient, being mostly influenced by the plasma density ratio in the source and expansion regions. The results of the study are compared with independent numerical studies.

  1. Simultaneous determination of paeoniflorin, albiflorin, ferulic acid, tetrahydropalmatine, protopine, typhaneoside, senkyunolide I in Beagle dogs plasma by UPLC-MS/MS and its application to a pharmacokinetic study after Oral Administration of Shaofu Zhuyu Decoction.

    PubMed

    Huang, Xiaochen; Su, Shulan; Cui, Wenxia; Liu, Pei; Duan, Jin-ao; Guo, Jianming; Li, Zhenhao; Shang, Erxin; Qian, Dawei; Huang, Zhijun

    2014-07-01

    In this present study, a sensitive and rapid UPLC-MS/MS method was developed for simultaneous quantification of paeoniflorin, albiflorin, ferulic acid, tetrahydropalmatine, protopine, typhaneoside and senkyunolide I in Beagle dog plasma after oral administration of the Shao-Fu-Zhu-Yu Decoction. Chloramphenicol and clarithromycin were used as internal standards. Plasma samples were processed by protein precipitation with methanol. The separation was performed on an Acquity BEH C18 column (100mm×2.1mm, 1.7μm) at a flow-rate of 0.4mL/min, using 0.1% formic acid-acetonitrile as mobile phase. Method validation was performed as per Food and Drug Administration guidelines and the results met the acceptance criteria. After validation, this method was successfully applied to a pharmacokinetic study. The results showed that the apparent plasma clearance of paeoniflorin, albiflorin, typhaneoside and senkyunolide I were significantly higher than others. Double peak was observed in plasma concentration curves of tetrahydropalmatine, the ferulic acid had a good absorption in Beagle dog plasma, and senkyunolide I was detected in plasma from the first blood sampling time (15min) and rapidly reached Tmax. The compound of typhaneoside has a low bioavailability according to the results. PMID:24907546

  2. The study of a plasma jet injected by an on-board plasma thruster

    NASA Astrophysics Data System (ADS)

    Grebnev, I. A.; Ivanov, G. V.; Khodnenko, V. P.; Morozov, A. I.; Perkov, I. A.; Pertsev, A. A.; Romanovskii, Iu. A.; Rylov, Iu. P.; Shishkin, G. G.; Trifonov, Iu. V.

    The injection of a steady plasma jet into the ionosphere results in interactions which were studied in experiments conducted onboard two Meteor satellites in 1977-1979. The jet parameters at the propulsion system output were as follows: propulsive mass: Xe; Xe (+) ion density at the nozzle section; 3 x 10 to the 11th per cu cm; plasma stream divergence: 20 degrees; jet velocity: 10-12 km/cm; ion energy: 130 eV; electron temperature: 1 + 3 eV. A Bennett-type modified radio-frequency mass-spectrometer and a two-channel electromagnetic wave analyzer were used for the measurements. It was found that (1) the injected plasma jet propagation depends on the jet injection pitch angle; (2) when the plasma jet was injected along the magnetic field, impactless jet spreading took place without considerable interaction with the ionospheric plasma; (3) when the plasma jet was injected across the magnetic field, considerable interaction was observed between the plasma jet/ionospheric plasma and the earth's magnetic field; and (4) electromagnetic fields were generated near the satellite by plasma jet interaction.

  3. Studies of the ablated plasma from experimental plasma gun disruption simulations

    NASA Astrophysics Data System (ADS)

    Rockett, P. D.; Hunter, J. A.; Bradley, J. T.; Gahl, J. M.; Litunovsky, V. N.; Ovchinnokov, I. B.; Ljublin, B. V.; Kuznetsov, B. E.; Titov, V. A.; Zhitlukhin, A.; Arkhipov, K.; Bakhtin, V.; Toporkov, D.

    1995-04-01

    Extensive simulations of tokamak disruptions have provided a picture of material erosion that is limited by the transfer of energy from the incident plasma to the armor solid surface through a dense plasma shield. Radiation spectra were recorded in the VUV and in the visible at the Efremov Laboratories on VIKA using graphite targets. The VUV data were recorded with a Sandia Labs transmission grating spectrograph, covering 1-40 nm. Plasma parameters were evaluated with incident plasma energy densities varying from 10-100 MJ/m 2. A second transmission grating spectrograph was taken to 2MK-200 at TRINITI to study the plasma-material interface in magnetic cusp plasma. Target materials included POCO graphite, ATJ graphite, boron nitride, and plasma-sprayed tungsten. Detailed spectra were recorded with a spatial resolution of ˜ 1 mm. Time-resolved data with 40-200 ns resolution was also recorded. The data from both plasma gun facilities demonstrated that the hottest plasma region was sitting several millimeters above the armor tile surface.

  4. Topical applications of resonance internal conversion in laser produced plasma

    NASA Astrophysics Data System (ADS)

    Karpeshin, F. F.

    2007-04-01

    Physical aspects of resonance effects arising in plasma due to interactions of nuclei with the electrons are considered. Among them are resonance conversion (TEEN) and the reverse process of NEET. These processes are of great importance for pumping the excited nuclear states (isomers) and for accelerating their decay. Experiment is discussed on studying the unique 3.5-eV 229m Th nuclide.

  5. Dynamical properties of non-equilibrium atmospheric plasma jets and their applications to plasma processing in liquids

    NASA Astrophysics Data System (ADS)

    Kitano, Katsuhisa; Satoshi, Ikawa; Furusho, Hitoshi; Nagasaki, Yukio; Hamaguchi, Satoshi

    2007-11-01

    Non-equilibrium atmospheric pressure plasma jets are discussed with the emphasis on their physics and applications. Plume-like plasmas, which may be called plasma jets, have been generated in a discharge system consisting of a dielectric/metal tube (through which He gas flows at the atmospheric pressure) and a single electrode attached to the tube, to which low-frequency, high-voltage pulses (˜10kV, ˜10kHz) are applied. With visible light images taken by a high-speed ICCD camera, it has been confirmed that the plasma jet consists of a series of small ``plasma bullets'' that are emitted intermittently from the powered electrode in sync with the positive voltage pulses. The observed ``plasma bullet'' may be interpreted as a fast moving ionization front. The plasma jets are energetic enough to generate highly reactive charge-neutral radicals but their gas temperatures remain low. Therefore the plasma jets are ideal for processing of liquid based materials at low temperatures and some examples of process applications, such as reduction of cations, polymerization of liquid monomers, and sterilization, will be also presented.

  6. Numerical studies of wall-plasma interactions and ionization phenomena in an ablative pulsed plasma thruster

    NASA Astrophysics Data System (ADS)

    Yang, Lei; Zeng, Guangshang; Tang, Haibin; Huang, Yuping; Liu, Xiangyang

    2016-07-01

    Wall-plasma interactions excited by ablation controlled arcs are very critical physical processes in pulsed plasma thrusters (PPTs). Their effects on the ionization processes of ablated vapor into discharge plasma directly determine PPT performances. To reveal the physics governing the ionization phenomena in PPT discharge, a modified model taking into account the pyrolysis effect of heated polytetrafluoroethylene propellant on the wall-plasma interactions was developed. The feasibility of the modified model was analyzed by creating a one-dimensional simulation of a rectangular ablative PPT. The wall-plasma interaction results based on this modified model were found to be more realistic than for the unmodified model; this reflects the dynamic changes of the inflow parameters during discharge in our model. Furthermore, the temporal and spatial variations of the different plasma species in the discharge chamber were numerically studied. The numerical studies showed that polytetrafluoroethylene plasma was mainly composed of monovalent ions; carbon and fluorine ions were concentrated in the upstream and downstream discharge chamber, respectively. The results based on this modified model were in good agreement with the experimental formation times of the various plasma species. A large number of short-lived and highly ionized carbon and fluorine species (divalent and trivalent ions) were created during initial discharge. These highly ionized species reached their peak density earlier than the singly ionized species.

  7. Two-dimensional studies of relativistic electron beam plasma instabilities in an inhomogeneous plasma

    SciTech Connect

    Shukla, Chandrasekhar; Das, Amita; Patel, Kartik

    2015-11-15

    Relativistic electron beam propagation in plasma is fraught with several micro instabilities like two stream, filamentation, etc., in plasma. This results in severe limitation of the electron transport through a plasma medium. Recently, however, there has been an experimental demonstration of improved transport of Mega Ampere of electron currents (generated by the interaction of intense laser with solid target) in a carbon nanotube structured solid target [G. Chatterjee et al., Phys. Rev. Lett. 108, 235005 (2012)]. This then suggests that the inhomogeneous plasma (created by the ionization of carbon nanotube structured target) helps in containing the growth of the beam plasma instabilities. This manuscript addresses this issue with the help of a detailed analytical study and 2-D Particle-In-Cell simulations. The study conclusively demonstrates that the growth rate of the dominant instability in the 2-D geometry decreases when the plasma density is chosen to be inhomogeneous, provided the scale length 1/k{sub s} of the inhomogeneous plasma is less than the typical plasma skin depth (c/ω{sub 0}) scale. At such small scale lengths channelization of currents is also observed in simulation.

  8. Plasma level monitoring of antidepressants: theoretical basis and clinical application.

    PubMed

    Gram, L F; Kragh-Sørensen, P; Kristensen, C B; Møller, M; Pedersen, O L; Thayssen, P

    1984-01-01

    For TCAs there is a strong rationale for drug level monitoring in clinical therapy. Therapeutic drug concentration ranges have been established in controlled studies with NT, imipramine, and AT. It has been shown that by appropriate choice of antidepressant and close monitoring of drug levels, treatment with antidepressants in elderly and other risk patients can be carried out effectively and safely, reducing the use of electroconvulsive therapy. Finally, the practical clinical use of antidepressant concentration measurements is now feasible and not expensive, and the analytical procedures can be established in most hospital settings. On the basis of these premises the following can be concluded: Plasma level monitoring should be used as a routine for imipramine, NT, and AT. Further plasma level studies on other antidepressants and in overdose cases should be initiated. Plasma level monitoring is indispensable in clinical research on antidepressants (trials, new drugs, toxicology). Pharmacokinetic considerations may be useful to determine which receptor effects are clinically relevant in therapy and toxicology. PMID:6380231

  9. Millimeter-Wave Imaging Technology Advancements for Plasma Diagnostics Applications

    NASA Astrophysics Data System (ADS)

    Kong, Xiangyu

    To realize fusion plant, the very first step is to understand the fundamental physics of materials under fusion conditions, i.e. to understand fusion plasmas. Our research group, Plasma Diagnostics Group, focuses on developing advanced tools for physicists to extract as much information as possible from fusion plasmas at millions degrees. The Electron Cyclotron Emission Imaging (ECEI) diagnostics is a very useful tool invented in this group to study fusion plasma electron temperature and it fluctuations. This dissertation presents millimeter wave imaging technology advances recently developed in this group to improve the ECEI system. New technologies made it more powerful to image and visualize magneto-hydrodynamics (MHD) activities and micro-turbulence in fusion plasmas. Topics of particular emphasis start from development of miniaturized elliptical substrate lens array. This novel substrate lens array replaces the previous generation substrate lens, hyper-hemispherical substrate lens, in terms of geometry. From the optical performance perspective, this substitution not only significantly simplifies the optical system with improved optical coupling, but also enhances the RF/LO coupling efficiency. By the benefit of the mini lens focusing properties, a wideband dual-dipole antenna array is carefully designed and developed. The new antenna array is optimized simultaneously for receiving both RF and LO, with sharp radiation patterns, low side-lobe levels, and less crosstalk between adjacent antennas. In addition, a high frequency antenna is also developed, which extends the frequency limit from 145 GHz to 220 GHz. This type of antenna will be used on high field operation tokamaks with toroidal fields in excess of 3 Tesla. Another important technology advance is so-called extended bandwidth double down-conversion electronics. This new electronics extends the instantaneous IF coverage from 2 to 9.2 GHz to 2 to 16.4 GHz. From the plasma point of view, it means that the

  10. Radar studies of midlatitude ionospheric plasma drifts

    NASA Astrophysics Data System (ADS)

    Scherliess, L.; Fejer, B. G.; Holt, J.; Goncharenko, L.; Amory-Mazaudier, C.; Buonsanto, M. J.

    2001-02-01

    We use incoherent scatter radar measurements from Millstone Hill and Saint Santin to study the midlatitude F region electrodynamic plasma drifts during geomagnetically quiet and active periods. We present initially a local time, season, and solar flux dependent analytical model of the quiet time zonal and meridional E×B drifts over these stations. We discuss, for the first time, the Saint Santin drift patterns during solar maximum. We have used these quiet time models to extract the geomagnetic perturbation drifts which were modeled as a function of the time history of the auroral electrojet indices. Our results illustrate the evolution of the disturbance drifts driven by the combined effects of prompt penetration and longer lasting perturbation electric fields. The meridional electrodynamic disturbance drifts have largest amplitudes in the midnight-noon sector. The zonal drifts are predominantly westward, with largest amplitudes in the dusk-midnight sector and, following a decrease in the high-latitude convection, they decay more slowly than the meridional drifts. The prompt penetration and steady state zonal disturbance drifts derived from radar measurements are in good agreement with results obtained from both the ion drift meter data on board the Dynamics Explorer 2 (DE 2) satellite and from the Rice Convection Model.

  11. Capillary plasma jet: A low volume plasma source for life science applications

    NASA Astrophysics Data System (ADS)

    Topala, I.; Nagatsu, M.

    2015-02-01

    In this letter, we present results from multispectroscopic analysis of protein films, after exposure to a peculiar plasma source, i.e., the capillary plasma jet. This plasma source is able to generate very small pulsed plasma volumes, in kilohertz range, with characteristic dimensions smaller than 1 mm. This leads to specific microscale generation and transport of all plasma species. Plasma diagnosis was realized using general electrical and optical methods. Depending on power level and exposure duration, this miniature plasma jet can induce controllable modifications to soft matter targets. Detailed discussions on protein film oxidation and chemical etching are supported by results from absorption, X-ray photoelectron spectroscopy, and microscopy techniques. Further exploitation of principles presented here may consolidate research interests involving plasmas in biotechnologies and plasma medicine, especially in patterning technologies, modified biomolecule arrays, and local chemical functionalization.

  12. Capillary plasma jet: A low volume plasma source for life science applications

    SciTech Connect

    Topala, I. E-mail: tmnagat@ipc.shizuoka.ac.jp; Nagatsu, M. E-mail: tmnagat@ipc.shizuoka.ac.jp

    2015-02-02

    In this letter, we present results from multispectroscopic analysis of protein films, after exposure to a peculiar plasma source, i.e., the capillary plasma jet. This plasma source is able to generate very small pulsed plasma volumes, in kilohertz range, with characteristic dimensions smaller than 1 mm. This leads to specific microscale generation and transport of all plasma species. Plasma diagnosis was realized using general electrical and optical methods. Depending on power level and exposure duration, this miniature plasma jet can induce controllable modifications to soft matter targets. Detailed discussions on protein film oxidation and chemical etching are supported by results from absorption, X-ray photoelectron spectroscopy, and microscopy techniques. Further exploitation of principles presented here may consolidate research interests involving plasmas in biotechnologies and plasma medicine, especially in patterning technologies, modified biomolecule arrays, and local chemical functionalization.

  13. Studies of Burning Plasma Physics in JET

    NASA Astrophysics Data System (ADS)

    Mayoral, Marie-Line

    2003-10-01

    In burning plasma experiments, the very energetic alpha particles resulting from Deuterium-Tritium fusion reactions will be the dominant heating mechanism. This type of heating is different in two aspects from the externally supplied heating dominant in present experiments. First, alpha particles heating depends on the local values of plasma density and temperature, but will also influence, in turn, these plasma parameters. We will consequently be faced with an intricate self-consistent plasma system, with less powerful outside actuators to control e.g. the fusion rate. Experiments have been performed at JET where a part of the external Radio Frequency (RF) heating, determined by the measured central density and temperature, has been used to simulate of the alpha heating and the abovementioned dependence. Secondly, the presence of very energetic particles with large orbits can influence the magneto-hydrodynamic stability of plasmas. Sawteeth, for example, can be temporarily stabilized, resulting in stronger sawtooth crashes when the higher stability limit is eventually crossed. Neo-classical tearing modes (NTMs), extremely damaging for the plasma confinement, are found to be associated with those large crashes. Energetic 4He ions injected at 120 keV and accelerated by RF power to over 2 MeV have provided the necessary energetic particles to investigate those effects. New scenarios have been used in order to control the stability of the sawteeth even in the presence of fast particles and prevent or delay the appearance of NTMs. Further results are expected from the planned trace tritium experiments foreseen on JET during October 2003. This will, together with state-of-the-art numerical simulations, deliver invaluable information for a better understanding and prediction of burning plasma behaviour.

  14. Studies of the ablated plasma from experimental plasma gun disruption simulations

    NASA Astrophysics Data System (ADS)

    Rockett, P. D.; Hunter, J. A.; Bradley, J. T., III; Gahl, J. M.; Zhitlukhin, A.; Arkhipov, K.; Bakhtin, V.; Toporkov, D.; Litunovsky, V. N.; Ovchinnokov, I. B.

    Extensive simulations of Tokamak disruptions have provided a picture of material erosion that is limited by the transfer of energy from the incident plasma to the armor solid surface through a dense vapor shield. Radiation spectra were recorded in the VUV and in the visible at the Efremov Laboratories on VIKA using graphite targets. The VUV data were recorded with a Sandia Labs transmission grating spectrograph, covering 1--40 nm. Plasma parameters were evaluated with incident plasma energy densities varying from 1--10 kJ/sq cm. A second transmission grating spectrograph was taken to 2MK-200 at TRINITI to study the plasma-material interface in magnetic cusp plasma. Target materials included POCO graphite, ATJ graphite, boron nitride, and plasma-sprayed tungsten. Detailed spectra were recorded with a spatial resolution of approximately 1 mm resolution. Time-resolved data with 40--200 ns resolution was also recorded. The data from both plasma gun facilities demonstrated that the hottest plasma region was sitting several millimeters above the armor tile surface.

  15. Studies of the ablated plasma from experimental plasma gun disruption simulations

    SciTech Connect

    Rockett, P.D.; Hunter, J.A.; Bradley, J.T.

    1994-07-01

    Extensive simulations of Tokamak disruptions have provided a picture of material erosion that is limited by the transfer of energy from the incident plasma to the armor solid surface through a dense vapor shield. Radiation spectra were recorded in the VUV and in the visible at the Efremov Laboratories on VIKA using graphite targets. The VUV data were recorded with a Sandia Labs transmission grating spectrograph, covering 1--40 nm. Plasma parameters were evaluated with incident plasma energy densities varying from 1--10 kJ/cm{sup 2}. A second transmission grating spectrograph was taken to 2MK-200 at TRINITI to study the plasma-material interface in magnetic cusp plasma. Target materials included POCO graphite, ATJ graphite, boron nitride, and plasma-sprayed tungsten. Detailed spectra were recorded with a spatial resolution of {approximately}1 mm resolution. Time-resolved data with 40--200 ns resolution was also recorded. The data from both plasma gun facilities demonstrated that the hottest plasma region was sitting several millimeters above the armor tile surface.

  16. Plasma treatments of wool fiber surface for microfluidic applications

    SciTech Connect

    Jeon, So-Hyoun; Hwang, Ki-Hwan; Lee, Jin Su; Boo, Jin-Hyo; Yun, Sang H.

    2015-09-15

    Highlights: • We used atmospheric plasma for tuning the wettability of wool fibers. • The wicking rates of the wool fibers increased with increasing treatment time. • The increasing of wettability results in removement of fatty acid on the wool surface. - Abstract: Recent progress in health diagnostics has led to the development of simple and inexpensive systems. Thread-based microfluidic devices allow for portable and inexpensive field-based technologies enabling medical diagnostics, environmental monitoring, and food safety analysis. However, controlling the flow rate of wool thread, which is a very important part of thread-based microfluidic devices, is quite difficult. For this reason, we focused on thread-based microfluidics in the study. We developed a method of changing the wettability of hydrophobic thread, including wool thread. Thus, using natural wool thread as a channel, we demonstrate herein that the manipulation of the liquid flow, such as micro selecting and micro mixing, can be achieved by applying plasma treatment to wool thread. In addition to enabling the flow control of the treated wool channels consisting of all natural substances, this procedure will also be beneficial for biological sensing devices. We found that wools treated with various gases have different flow rates. We used an atmospheric plasma with O{sub 2}, N{sub 2} and Ar gases.

  17. Plasma RF Switching Elements for Cell Phone Applications

    NASA Astrophysics Data System (ADS)

    Linardakis, Peter; Borg, Gerard G.; Harris, Jeffrey H.

    2002-10-01

    The functionality of modern multi-band, multi-system cell phones is provided by a large number of RF switches. Future phones will require an even greater number of these switches to implement hardware such as agile antennas. The ever increasing need for higher performance and lower power consumption have brought the RF PIN diode to the edge of its capabilities in these applications. RF micro-electromechanical (MEMS) switches can easily provide the required low insertion loss, low inter-modulation and low power consumption combination, but their reliability limits are not yet satisfactory to industry. In conjunction with Motorola Personal Communications Sector (PCS), PRL is undertaking a project to examine the possibility of using plasma in a completely novel type of RF switch. A basic concept of variable ``plasma capacitors'' constructed from DC commercial fluorescent tubes has been analyzed up to 1.3 GHz. The four different configurations tested show some consistent behavior and a definite impedance change between the on and off states. A simple model reliant on RF sheath theory also shows some agreement.

  18. Biomedical Applications of Low Temperature Atmospheric Pressure Plasmas to Cancerous Cell Treatment and Tooth Bleaching

    NASA Astrophysics Data System (ADS)

    Lee, Jae Koo; Kim, Myoung Soo; Byun, June Ho; Kim, Kyong Tai; Kim, Gyoo Cheon; Park, Gan Young

    2011-08-01

    Low temperature atmospheric pressure plasmas have attracted great interests and they have been widely applied to biomedical applications to interact with living tissues, cells, and bacteria due to their non-thermal property. This paper reviews the biomedical applications of low temperature atmospheric pressure plasmas to cancerous cell treatment and tooth bleaching. Gold nanoparticles conjugated with cancer-specific antibodies have been introduced to cancerous cells to enhance selective killing of cells, and the mechanism of cell apoptosis induced by plasma has been investigated. Tooth exposed to helium plasma jet with hydrogen peroxide has become brighter and the productions of hydroxyl radicals from hydrogen peroxide have been enhanced by plasma exposure.

  19. Micro-column plasma emission liquid chromatograph. [Patent application

    DOEpatents

    Gay, D.D.

    1982-08-12

    In a direct current plasma emission spectrometer for use in combination with a microcolumn liquid chromatograph, an improved plasma source unit is claimed. The plasma source unit includes a quartz capillary tube having an inlet means, outlet off gas means and a pair of spaced electrodes defining a plasma region in the tube. The inlet means is connected to and adapted to receive eluant of the liquid chromatograph along with a stream of plasma-forming gas. There is an opening through the wall of the capillary tube penetrating into the plasma region. A soft glass capillary light pipe is disposed at the opening, is connected to the spectrometer, and is adapted to transmit light passing from the plasma region to the spectrometer. There is also a source of electromotive force connected to the electrodes sufficient to initiate and sustain a plasma in the plasma region of the tube.

  20. Applications of X-ray lasers utilizing plasmas that are only a few times ionised

    SciTech Connect

    Nilsen, J; Scofield, J H

    2004-06-09

    With the advent of tabletop X-ray lasers that operate at high repetition rate more emphasis is being put on finding useful applications for these lasers. The 14.7 nm Ni-like Pd X-ray laser at Lawrence Livermore National Laboratory is being used to do many interferometer experiments. As detailed quantitative comparisons are done between experiments and code simulations it is clear that some of the assumptions used to analyze the experiments need to be modified as one explores plasmas that are only a few times ionized. In the case of aluminium plasmas that have been analyzed with interferometers there has been some unusual behavior where the fringe lines bend the wrong way. In this work we will discuss how the index of refraction for aluminium is far more complicated than generally assumed because there are significant contributions to the index from the continuum and line structure of the bound electrons that can dominate the free electron contribution and even cause the index to be greater than one. We will also discuss some potential applications of the high repetition rate Ne-like Ar X-ray laser at 46.9 nm. In particular we will present modeling that shows how the Ar laser could be used to modify the absorption coefficient of a helium plasma and allow one to study the kinetics of plasmas with very low temperatures of a few eV. We will also discuss frequency doubling of the 46.9 nm laser.

  1. Production of a composite hyaluronic acid/gelatin blood plasma gel for hydrogel-based adipose tissue engineering applications.

    PubMed

    Korurer, Esra; Kenar, Halime; Doger, Emek; Karaoz, Erdal

    2014-07-01

    Standard approaches to soft-tissue reconstruction include autologous adipose tissue transplantation, but most of the transferred adipose tissue is generally reabsorbed in a short time. To overcome this problem, long lasting implantable hydrogel materials that can support tissue regeneration must be produced. The purpose of this study was to evaluate the suitability of composite 3D natural origin scaffolds for reconstructive surgery applications through in vitro tests. The Young's modulus of the glutaraldehyde crosslinked hyaluronic acid/gelatin (HA/G) plasma gels, composed of human platelet-poor plasma, gelatin and human umbilical cord hyaluronic acid, was determined as 3.5 kPa, close to that of soft tissues. The composite HA/G plasma gels had higher porosity than plain plasma gels (72.5% vs. 63.86%). Human adipose tissue derived stem cells (AD-MSCs) were isolated from human lipoaspirates and characterized with flow cytometry, and osteogenic and adipogenic differentiation. Cell proliferation assay of AD-MSCs on the HA/G plasma gels revealed the nontoxic nature of these constructs. Adipogenic differentiation was distinctly better on HA/G plasma gels than on plain plasma gels. The results showed that the HA/G plasma gel with its suitable pore size, mechanical properties and excellent cell growth and adipogenesis supporting properties can serve as a useful scaffold for adipose tissue engineering applications.

  2. Development and Validation of a High-Performance Liquid Chromatography–Tandem Mass Spectrometry Method for the Simultaneous Determination of Irinotecan and Its Main Metabolites in Human Plasma and Its Application in a Clinical Pharmacokinetic Study

    PubMed Central

    Marangon, Elena; Posocco, Bianca; Mazzega, Elisa; Toffoli, Giuseppe

    2015-01-01

    Irinotecan is currently used in several cancer regimens mainly in colorectal cancer (CRC). This drug has a narrow therapeutic range and treatment can lead to side effects, mainly neutropenia and diarrhea, frequently requiring discontinuing or lowering the drug dose. A wide inter-individual variability in irinotecan pharmacokinetic parameters and pharmacodynamics has been reported and associated to patients’ genetic background. In particular, a polymorphism in the UGT1A1 gene (UGT1A1*28) has been linked to an impaired detoxification of SN-38 (irinotecan active metabolite) to SN-38 glucuronide (SN-38G) leading to increased toxicities. Therefore, therapeutic drug monitoring of irinotecan, SN-38 and SN-38G is recommended to personalize therapy. In order to quantify simultaneously irinotecan and its main metabolites in patients’ plasma, we developed and validated a new, sensitive and specific HPLC–MS/MS method applicable to all irinotecan dosages used in clinic. This method required a small plasma volume, addition of camptothecin as internal standard and simple protein precipitation. Chromatographic separation was done on a Gemini C18 column (3 μM, 100 mm x 2.0 mm) using 0.1% acetic acid/bidistilled water and 0.1% acetic acid/acetonitrile as mobile phases. The mass spectrometer worked with electrospray ionization in positive ion mode and selected reaction monitoring. The standard curves were linear (R2 ≥0.9962) over the concentration ranges (10–10000 ng/mL for irinotecan, 1–500 ng/mL for SN-38 and SN-38G and 1–5000 ng/mL for APC) and had good back-calculated accuracy and precision. The intra- and inter-day precision and accuracy, determined on three quality control levels for all the analytes, were always <12.3% and between 89.4% and 113.0%, respectively. Moreover, we evaluated this bioanalytical method by re-analysis of incurred samples as an additional measure of assay reproducibility. This method was successfully applied to a pharmacokinetic study in

  3. Development and validation of a high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous determination of irinotecan and its main metabolites in human plasma and its application in a clinical pharmacokinetic study.

    PubMed

    Marangon, Elena; Posocco, Bianca; Mazzega, Elisa; Toffoli, Giuseppe

    2015-01-01

    Irinotecan is currently used in several cancer regimens mainly in colorectal cancer (CRC). This drug has a narrow therapeutic range and treatment can lead to side effects, mainly neutropenia and diarrhea, frequently requiring discontinuing or lowering the drug dose. A wide inter-individual variability in irinotecan pharmacokinetic parameters and pharmacodynamics has been reported and associated to patients' genetic background. In particular, a polymorphism in the UGT1A1 gene (UGT1A1*28) has been linked to an impaired detoxification of SN-38 (irinotecan active metabolite) to SN-38 glucuronide (SN-38G) leading to increased toxicities. Therefore, therapeutic drug monitoring of irinotecan, SN-38 and SN-38G is recommended to personalize therapy. In order to quantify simultaneously irinotecan and its main metabolites in patients' plasma, we developed and validated a new, sensitive and specific HPLC-MS/MS method applicable to all irinotecan dosages used in clinic. This method required a small plasma volume, addition of camptothecin as internal standard and simple protein precipitation. Chromatographic separation was done on a Gemini C18 column (3 μM, 100 mm x 2.0 mm) using 0.1% acetic acid/bidistilled water and 0.1% acetic acid/acetonitrile as mobile phases. The mass spectrometer worked with electrospray ionization in positive ion mode and selected reaction monitoring. The standard curves were linear (R2 ≥0.9962) over the concentration ranges (10-10000 ng/mL for irinotecan, 1-500 ng/mL for SN-38 and SN-38G and 1-5000 ng/mL for APC) and had good back-calculated accuracy and precision. The intra- and inter-day precision and accuracy, determined on three quality control levels for all the analytes, were always <12.3% and between 89.4% and 113.0%, respectively. Moreover, we evaluated this bioanalytical method by re-analysis of incurred samples as an additional measure of assay reproducibility. This method was successfully applied to a pharmacokinetic study in metastatic

  4. Numerical study of Si nanoparticle formation by SiCl4 hydrogenation in RF plasma

    NASA Astrophysics Data System (ADS)

    Rehmet, Christophe; Cao, Tengfei; Cheng, Yi

    2016-04-01

    Nanocrystalline silicon (nc-Si) is a promising material for many applications related to electronics and optoelectronics. This work performs numerical simulations in order to understand a new process with high deposition rate production of nc-Si in a radio-frequency plasma reactor. Inductive plasma formation, reaction kinetics and nanoparticle formation have been considered in a sophisticated model. Results show that the plasma parameters could be adjusted in order to improve selectivity between nanoparticle and molecule formation and, thus, the deposition rate. Also, a parametric study helps to optimize the system with appropriate operating conditions.

  5. Esterification by the Plasma Acidic Water: Novel Application of Plasma Acid

    NASA Astrophysics Data System (ADS)

    Gu, Ling

    2014-03-01

    This work explores the possibility of plasma acid as acid catalyst in organic reactions. Plasma acidic water was prepared by dielectric barrier discharge and used to catalyze esterification of n-heptanioc acid with ethanol. It is found that the plasma acidic water has a stable and better performance than sulfuric acid, meaning that it is an excellent acid catalyst. The plasma acidic water would be a promising alternative for classic mineral acid as a more environment friendly acid.

  6. Development of plasma needle to be used for biomedical applications

    NASA Astrophysics Data System (ADS)

    Bora, B.; Jain, J.; Inestrosa-Izurieta, M. J.; Avaria, G.; Moreno, J.; Pavez, C.; Marcelain, K.; Armisen, R.; Soto, L.

    2016-05-01

    Plasma needle is a novel design of a plasma source at atmospheric pressure to achieve a non-thermal plasma jet. The advantage of the plasma needle is that it can be operated in open air, outside a vessel. The plasma that is generated with the plasma needle is small (about one millimetre) and non-thermal, the temperature of the neutral particles and ions is in about room temperature and suitably can interact with living biological cell without damaging the cell. In this work, we report the development of a plasma needle, which is operated by a dc power source and produced a stable plasma jet on water surface. Argon gas is used to operate the plasma needle. The preliminary electrical diagnostics of the plasma needle shows that the discharge is filamentary in nature. For diagnostic of the plasma jet produced by the developed plasma needle, the produced plasma jet is directed to water surface and characterization are carried out by means of electrical discharge characteristics and optical emission spectroscopy. In this work, preliminary results of the diagnostic will be presented.

  7. Quantum theory of the dielectric constant of a magnetized plasma and astrophysical applications. I.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Ventura, J.

    1972-01-01

    A quantum mechanical treatment of an electron plasma in a constant and homogeneous magnetic field is considered, with the aim of (1) defining the range of validity of the magnetoionic theory (2) studying the deviations from this theory, in applications involving high densities, and intense magnetic field. While treating the magnetic field exactly, a perturbation approach in the photon field is used to derive general expressions for the dielectric tensor. Numerical estimates on the range of applicability of the magnetoionic theory are given for the case of the 'one-dimensional' electron gas, where only the lowest Landau level is occupied.

  8. Application of platelet-rich plasma in maxillofacial surgery: clinical evaluation.

    PubMed

    Gentile, Pietro; Bottini, Davide J; Spallone, Diana; Curcio, Beniamino Cristiano; Cervelli, Valerio

    2010-05-01

    The authors report their experience on 15 cases, including reconstructive surgery of the jaws, postextraction alveolar bone regeneration, and oral implantology. The aim of the study was to evaluate the different effects on jaws' bone regeneration with or without the use of local application of platelet-rich plasma (PRP). The results we report showed the efficacy of the PRP treatment: postoperative patients' satisfaction and low-morbidity course confirmed the quality of the results. The article will help the reader to (1) understand the PRP preparation, (2) find local applications in oral and maxillofacial surgery, and (3) evaluate the general effect of PRP.

  9. Spark Plasma Sintering of Fuel Cermets for Nuclear Reactor Applications

    SciTech Connect

    Yang Zhong; Robert C. O'Brien; Steven D. Howe; Nathan D. Jerred; Kristopher Schwinn; Laura Sudderth; Joshua Hundley

    2011-11-01

    The feasibility of the fabrication of tungsten based nuclear fuel cermets via Spark Plasma Sintering (SPS) is investigated in this work. CeO2 is used to simulate fuel loadings of UO2 or Mixed-Oxide (MOX) fuels within tungsten-based cermets due to the similar properties of these materials. This study shows that after a short time sintering, greater than 90 % density can be achieved, which is suitable to possess good strength as well as the ability to contain fission products. The mechanical properties and the densities of the samples are also investigated as functions of the applied pressures during the sintering.

  10. Application of Platelet-Rich Plasma to Disorders of the Knee Joint

    PubMed Central

    Mandelbaum, Bert R.; McIlwraith, C. Wayne

    2013-01-01

    Importance. The promising therapeutic potential and regenerative properties of platelet-rich plasma (PRP) have rapidly led to its widespread clinical use in musculoskeletal injury and disease. Although the basic scientific rationale surrounding PRP products is compelling, the clinical application has outpaced the research. Objective. The purpose of this article is to examine the current concepts around the basic science of PRP application, different preparation systems, and clinical application of PRP in disorders in the knee. Evidence Acquisition. A systematic search of PubMed for studies that evaluated the basic science, preparation and clinical application of platelet concentrates was performed. The search used terms, including platelet-rich plasma or PRP preparation, activation, use in the knee, cartilage, ligament, and meniscus. Studies found in the initial search and related studies were reviewed. Results. A comprehensive review of the literature supports the potential use of PRP both nonoperatively and intraoperatively, but highlights the absence of large clinical studies and the lack of standardization between method, product, and clinical efficacy. Conclusions and Relevance. In addition to the call for more randomized, controlled clinical studies to assess the clinical effect of PRP, at this point, it is necessary to investigate PRP product composition and eventually have the ability to tailor the therapeutic product for specific indications. PMID:26069674

  11. Confinement Studies in High Temperature Spheromak Plasmas

    SciTech Connect

    Hill, D N; Mclean, H S; Wood, R D; Casper, T A; Cohen, B I; Hooper, E B; LoDestro, L L; Pearlstein, L D; Romero-Talamas, C

    2006-10-23

    Recent results from the SSPX spheromak experiment demonstrate the potential for obtaining good energy confinement (Te > 350eV and radial electron thermal diffusivity comparable to tokamak L-mode values) in a completely self-organized toroidal plasma. A strong decrease in thermal conductivity with temperature is observed and at the highest temperatures, transport is well below that expected from the Rechester-Rosenbluth model. Addition of a new capacitor bank has produced 60% higher magnetic fields and almost tripled the pulse length to 11ms. For plasmas with T{sub e} > 300eV, it becomes feasible to use modest (1.8MW) neutral beam injection (NBI) heating to significantly change the power balance in the core plasma, making it an effective tool for improving transport analysis. We are now developing detailed designs for adding NBI to SSPX and have developed a new module for the CORSICA transport code to compute the correct fast-ion orbits in SSPX so that we can simulate the effect of adding NBI; initial results predict that such heating can raise the electron temperature and total plasma pressure in the core by a factor of two.

  12. NSTX Diagnostics for Fusion Plasma Science Studies

    SciTech Connect

    R. Kaita; D. Johnson; L. Roquemore; M. Bitter; F. Levinton; F. Paoletti; D. Stutman; and the NSTX Team

    2001-07-05

    This paper will discuss how plasma science issues are addressed by the diagnostics for the National Spherical Torus Experiment (NSTX), the newest large-scale machine in the magnetic confinement fusion (MCF) program. The development of new schemes for plasma confinement involves the interplay of experimental results and theoretical interpretations. A fundamental requirement, for example, is a determination of the equilibria for these configurations. For MCF, this is well established in the solutions of the Grad-Shafranov equation. While it is simple to state its basis in the balance between the kinetic and magnetic pressures, what they are as functions of space and time are often not easy to obtain. Quantities like the plasma pressure and current density are not directly measurable. They are derived from data that are themselves complex products of more basic parameters. The same difficulties apply to the understanding of plasma instabilities. Not only are the needs for spatial and temporal resolution more stringent, but the wave parameters which characterize the instabilities are difficult to resolve. We will show how solutions to the problems of diagnostic design on NSTX, and the physics insight the data analysis provides, benefits both NSTX and the broader scientific community.

  13. Laboratory Studies of Supersonic Magnetized Plasma Jets and Radiative Shocks

    NASA Astrophysics Data System (ADS)

    Lebedev, Sergey

    2013-06-01

    In this talk I will focus on laboratory plasma experiments producing magnetically driven supersonic plasma jets and on the interaction of these jets with ambient media. The experiments are scalable to astrophysical flows in that the critical dimensionless numbers such as the plasma collisionality, the plasma beta, the Reynolds number and the magnetic Reynolds number are all in the astrophysically appropriate ranges. The experimental results will be compared with computer simulations performed with laboratory plasma codes and with astrophysical codes. In the experiments the jets are driven and collimated by the toroidal magnetic fields and it is found that the level of MHD instabilities in the jets strongly depends on the strength of the field represented by the ratio of the thermal to magnetic field pressures (plasma beta). The experiments show the possibility of formation of episodic outflows, with periodic ejections of magnetic bubbles naturally evolving into a heterogeneous jet propagating inside a channel made of self-collimated magnetic cavities [1,2]. We also found that it is possible to form quasi-laminar jets which are “indirectly” collimated by the toroidal magnetic fields, but this requires the presence of the lower density halo plasma surrounding the central jet [3]. Studies of the radiative shocks formed in the interaction of the supersonic magnetized plasma flows with ambient plasma will be also presented, and the development of cooling instabilities in the post-shock plasma will be discussed. This research was sponsored by EPSRC Grant No. EP/G001324/1 and by the OFES DOE under DOE Cooperative Agreement No. DE-SC-0001063. References 1. A. Ciardi, S.V. Lebedev, A. Frank et al., The Astrophysical Journal, 691: L147-L150 (2009) 2. F.A. Suzuki-Vidal, S.V. Lebedev, S.N. Bland et al., Physics of Plasmas, 17, 112708 (2010). 3. F.A. Suzuki-Vidal, M. Bocchi, S.V. Lebedev et al., Physics of Plasmas, 19, 022708 (2012).

  14. Applications of the ArbiTER edge plasma eigenvalue code

    NASA Astrophysics Data System (ADS)

    Baver, D. A.; Myra, J. R.; Umansky, M. V.

    2013-10-01

    ArbiTER is a flexible eigenvalue code designed for plasma physics applications. This code uses an equation and topology parser to determine how a particular set of linearized model equations is spatially discretized. The resulting matrix form is then solved using the SLEPc eigensolver package. The equation and topology parsers permit a wide variety of capabilities, including variable numbers of dimensions, both finite difference and finite element methods, and irregular boundary conditions. Recent upgrades also permit parallel operation and the solution of source-driven problems. Two applications of this code will be presented, both as demonstrations of capability and as benchmark cases. One of these is the calculation of resistive ballooning modes with fully kinetic electrons. This will demonstrate the capacity for solving kinetic problems. The other is the use of extended spatial domains for ballooning stability analysis. This will demonstrate the utility of extra dimensions in calculations with fluid models. Work supported by the U.S. DOE grant DE-SC0006562.

  15. Kinetic Theory in Hot Plasmas and Neutral Gases Applications to the Computation of the transport coefficients

    SciTech Connect

    Bendib, A.

    2008-09-23

    The conference is devoted to the study of systems consisting of a large number of particles by using the kinetic theory. In a first part, we present a general overview of the kinetic theory. In particular, the role of the correlations between particles is shown and discussed through the main models reported in the literature. In a second part, we present three applications to the transport properties in plasmas and neutral gases. The first application is devoted to the transport in hot plasmas perturbed with respect to the global equilibrium. The quasi-static and collisionless distribution function and transport coefficients are established. The influence of relativistic effects is also discussed. The second application deals with strongly inhomogeneous magnetized plasmas. The transport coefficients of Braginskii are calculated numerically in the local and the weakly nonlocal approximations. New nonlocal transport coefficients are emphasized. Finally, we apply the kinetic theory to the neutral gases by calculating the semi-collisional dispersion relation of acoustic waves. In particular, the dispersion and the damping of these waves in rarefied gases are highlighted. The method used to solve the kinetic equations is compared with the conventional method of Chapman-Enskog.

  16. Dusty plasmas

    SciTech Connect

    Jones, M.E.; Winske, D.; Keinigs, R.; Lemons, D.

    1996-05-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project has been to develop a fundamental understanding of dusty plasmas at the Laboratory. While dusty plasmas are found in space in galactic clouds, planetary rings, and cometary tails, and as contaminants in plasma enhanced fabrication of microelectronics, many of their properties are only partially understood. Our work has involved both theoretical analysis and self-consistent plasma simulations to understand basic properties of dusty plasmas related to equilibrium, stability, and transport. Such an understanding can improve the control and elimination of plasma dust in industrial applications and may be important in the study of planetary rings and comet dust tails. We have applied our techniques to the study of charging, dynamics, and coagulation of contaminants in plasma processing reactors for industrial etching and deposition processes and to instabilities in planetary rings and other space plasma environments. The work performed in this project has application to plasma kinetics, transport, and other classical elementary processes in plasmas as well as to plasma waves, oscillations, and instabilities.

  17. Acceleration of compact toroid plasma rings for fusion applications

    NASA Astrophysics Data System (ADS)

    Hartman, C. W.; Barr, W. L.; Eddleman, J. L.; Gee, M.; Hammer, J. H.; Ho, S. K.; Logan, B. G.; Meeker, D. J.; Mirin, A. A.; Nevins, W. M.

    1988-08-01

    We describe experimental results for a new type of collective accelerator based on magnetically confined compact torus (CT) plasma rings and discuss applications to both inertial and magnetic fusion. We have demonstrated the principle of CT acceleration in the RACE device with acceleration of 0.5 mg ring masses to 400 km/s and 0.02 mg ring masses to 1400 km/s at greater than or equal to 30 percent efficiency. Scaling the CT accelerator to the multi-megajoule level could provide an efficient, economical driver for inertial fusion (ICF) or magnetically insulated inertial fusion. Efficient conversion to X-rays for driving hohlraum-type ICF targets has been modeled using a radiation-hydrodynamics code. At less demanding conditions than required for ICF, a CT accelerator can be applied to fueling and current drive in tokamaks. Fueling is accomplished by injecting CTs at the required rate to sustain the particle inventory and at a velocity sufficient to penetrate to the magnetic axis before CT dissolution. Current drive is a consequence of the magnetic helicity content of the CT, which is approximately conserved during reconnection of the CT fields with the tokamak. Major areas of uncertainty in CT fueling and current drive concern the mechanism by which CTs will stop in a tokamak plasma and the effects of the CT on energy confinement and magnetic stability. Bounds on the required CT injection velocity are obtained by considering drag due to emission of an Alfven-wave wake and rapid reconnection and tilting on the internal Alfven time scale of the CT. Preliminary results employing a 3-D, resistive MHD code show rapid tilting with the CT aligning its magnetic moment with the tokamak field. Requirements for an experimental test of CT injection and scenarios for fueling a reactor will also be discussed.

  18. Experimental investigation on geometrical aspects of micro-plasma deposited tool steel for repair applications

    NASA Astrophysics Data System (ADS)

    Jhavar, S.; Paul, C. P.; Jain, N. K.

    2014-08-01

    Recent advancement in direct material deposition processes found wide applications in rapid prototyping, manufacturing and tooling industry. Micro-plasma deposition is one of the recent developments in this domain. This paper reports the deployment of newly integrated micro-plasma deposition system for the deposition of AISI P-20 tool steel on the AISI P20 tool steel substrate. A number of test tracks for single track deposition were deposited at the various combination of processing parameters. The sets of parameters yielding good deposits were selected to deposit overlap tracks. The geometry of single and overlapped tracks was evaluated to understand the parametric dependence. The study indicates that the aspect ratio of track geometry (ratio of width to height of track) is dependent on the processing parameters and the discharge current is identified as the most dominating parameters (contribution = 44%), followed by scan speed (contribution = 26.68%) and wire feed rate (contribution = 26.98%) with almost same effect. The microscopic study of the deposits indicates that the material deposited at the optimum processing parameters is free from surface and bulk defects. The estimated material properties are found to be at par with conventional processed material. This feasibility study proved that the micro-plasma deposition can be used for the generation of surfaces and multi-featured material deposition. It paved a way for the application of the process in die/mold repairs.

  19. Multi-dipolar microwave plasmas and their application to negative ion production

    SciTech Connect

    Béchu, S.; Bès, A.; Lacoste, A.; Aleiferis, S.; Ivanov, A. A. Jr.; Bacal, M.

    2013-10-15

    During the past decade multi-dipolar plasmas have been employed for various purposes such as surface treatments in biomedicine, physical and chemical vapour deposition for hydrogen storage, and applications in mechanical engineering. On the other hand, due to the design and operational mode of these plasma sources (i.e., strong permanent magnets for the electron cyclotron resonance coupling, low working pressure, and high electron density achieved) they are suitable for studying fundamental mechanisms involved in negative ion sources used in magnetically confined fusion and particle accelerators. Thus, this study presents an overview of fundamental results obtained with: (i) a single dipolar source, (ii) a network of seven dipolar plasma sources inserted into a magnetic multipolar chamber (Camembert III), and (iii) four dipolar sources housed in a smaller metallic cylinder (ROSAE III). Investigations with Langmuir probes of electron energy probability functions revealed the variation of the plasma properties versus the radial distance from the axis of a dipolar source in its mid plane and allowed the determination of the proportion between hot and cold electron populations in both chambers. These results are compared with the density of hydrogen negative ions, measured using the photodetachment technique. Electron energy probability functions obtained in these different configurations show the possibility of both hot and cold electron production. The former is a prerequisite for increasing the vibrational level of molecules and the dissociation degree and the latter for producing negative ions via dissociative attachment of the cold electrons or via surface production induced by H atoms.

  20. Analytical and Numerical Studies of the Complex Interaction of a Fast Ion Beam Pulse with a Background Plasma

    SciTech Connect

    Igor D. Kaganovich; Edward A. Startsev; Ronald C. Davidson

    2003-11-25

    Plasma neutralization of an intense ion beam pulse is of interest for many applications, including plasma lenses, heavy ion fusion, high energy physics, etc. Comprehensive analytical, numerical, and experimental studies are underway to investigate the complex interaction of a fast ion beam with a background plasma. The positively charged ion beam attracts plasma electrons, and as a result the plasma electrons have a tendency to neutralize the beam charge and current. A suite of particle-in-cell codes has been developed to study the propagation of an ion beam pulse through the background plasma. For quasi-steady-state propagation of the ion beam pulse, an analytical theory has been developed using the assumption of long charge bunches and conservation of generalized vorticity. The analytical results agree well with the results of the numerical simulations. The visualization of the data obtained in the numerical simulations shows complex collective phenomena during beam entry into and ex it from the plasma.

  1. Study plasma interactions in the auroral ionosphere

    NASA Technical Reports Server (NTRS)

    Anderson, H. R.; Wolf, R. A.

    1983-01-01

    Analyzed data from rocket flight, 29.007UE is presented. In a discrete electron arc the measured upward moving electrons are well accounted for by secondaries produced in collisional scattering of the measured downcoming electrons. No collective mechanisms need to invoke. The low energy downcoming electrons are accounted for by thermal plasma accelerated through a potential drop of a few kV that specularly reflects upward-moving lower energy electrons. No low altitude collective effects need to invoke in the arc. Simultaneous measurements of electric field by double probes on 29.007 and the Chatanika Radar allow one to infer that there are upward drifting ions above the discrete electron arc, and there is a westward neutral wind in the discrete arc. Two rocket payloads were built to investigate plasma effects in the pulsating aurora.

  2. Helicon Plasma Source Optimization Studies for VASIMR

    NASA Technical Reports Server (NTRS)

    Goulding, R. H.; Baity, F. W.; Barber, G. C.; Carter, M. D.; ChangDiaz, F. R.; Pavarin, D.; Sparks, D. O.; Squire J. P.

    1999-01-01

    A helicon plasma source at Oak Ridge National Laboratory is being used to investigate operating scenarios relevant to the VASIMR (VAriable Specific Impulse Magnetoplasma Rocket). These include operation at high magnetic field (> = 0.4 T), high frequency (<= 30 MHz), high power (< = 3 kW), and with light ions (He+, H+). To date, He plasmas have been produced with n(sub e0) = 1.7 x 10(exp 19)/cu m (measured with an axially movable 4mm microwave interferometer), with Pin = I kW at f = 13.56 MHz and absolute value of B(sub 0) = 0.16 T. In the near future, diagnostics including a mass flow meter and a gridded energy analyzer array will be added to investigate fueling efficiency and the source power balance. The latest results, together with modeling results using the EMIR rf code, will be presented.

  3. PLASMA-2013: International Conference on Research and Applications of Plasmas (Warsaw, Poland, 2-6 September 2013)

    NASA Astrophysics Data System (ADS)

    Sadowski, Marek J.

    2014-05-01

    The PLASMA-2013 International Conference on Research and Applications of Plasmas was held in Warsaw (Poland) from 2 to 6 September 2013. The conference was organized by the Institute of Plasma Physics and Laser Microfusion, under the auspices of the Polish Physical Society. The scope of the PLASMA conferences, which have been organized every two years since 1993, covers almost all issues of plasma physics and fusion research as well as selected problems of plasma technology. The PLASMA-2013 conference topics included: •Elementary processes and general plasma physics. •Plasmas in tokamaks and stellarators (magnetic confinement fusion). •Plasmas generated by laser beams and inertial confinement fusion. •Plasmas produced by Z-pinch and plasma-focus discharges. •Low-temperature plasma physics. •Space plasmas and laboratory astrophysics. •Plasma diagnostic methods and applications of plasmas. This conference was designed not only for plasma researchers and engineers, but also for students from all over the world, in particular for those from Central and Eastern Europe. Almost 140 participants had the opportunity to hear 9 general lectures, 11 topical talks and 26 oral presentations, as well as to see and discuss around 120 posters. From about 140 contributions, after the preparation of about 100 papers and the peer review process, only 74 papers have been accepted for publication in this topical issue. Acknowledgments Acting on behalf of the International Scientific Committee I would like to express our thanks to all the invited speakers and all the participants of the PLASMA-2013 conference for their numerous contributions. In particular, I wish to thank all of the authors of papers submitted for publication in this topical issue of Physica Scripta . Particular thanks are due to all of the reviewers for their valuable reports and comments, which helped to improve the quality of many of the papers. International Scientific Committee Marek J Sadowski, NCBJ

  4. LC determination of luteolin-7-O-β-D-glucoside and apigenin-7-O-β-D-glucoside in rat plasma after administration of Humulus scandens extract and its application to pharmacokinetic studies.

    PubMed

    Chen, Zaixing; Ying, Xixiang; Meng, Shu; Zhu, Xu; Jiang, Hong; Cao, Qishen; Wang, Lin; Meng, Fanhao

    2012-01-01

    The present study was to investigate the pharmacokinetics of luteolin-7-O-β-D-glucoside (LGL) and apigenin-7-O-β-D-glucoside (AGL) in rat plasma after intravenous administration of the Humulus scandens extract (HSE). A simple and accurate high-performance liquid chromatographic (HPLC) method was successfully developed for simultaneous determination of LGL and AGL in rat plasma after the plasma protein was precipitated with methanol. HPLC analysis was performed on a C₁₈ column with UV detection at 350 nm and a mobile phase of methanol-0.2% phosphoric acid (1 : 1, v/v). Calibration curves of LGL and AGL were linear over the concentration range of 0.16-20.0 and 0.06-7.20 µg mL⁻¹, respectively. The accuracy and precision of the two analytes at low, medium and high concentrations were within the range of -3.4% to 8.1%. The relative standard deviations (RSDs) of the intra- and inter-day precisions were less than 11.7% and 10.0%, respectively. The extraction recoveries (n = 5) varied from 91.9% to 104.1% for LGL and from 92.6% to 109.3% for AGL. The method was fully validated and successfully applied to a pharmacokinetic study of LGL and AGL in rat plasma after the intravenous administration of HSE. PMID:21756194

  5. Numerical Studies of High-Z Plasma in the HyperV Plasma Guns

    NASA Astrophysics Data System (ADS)

    Wu, Linchun; Messer, Sarah; Witherspoon, F. Douglas; Welch, Dale; Thoma, Carsten; Phillips, Mike; Bogatu, I. Nick; Galkin, Sergei; Macfarlane, Joe; Golovkin, Igor

    2010-11-01

    Numerical studies of railguns and coaxial guns at HyperV Technologies Corp. include simulations of hypervelocity plasma transport in the gun, plasma expansion out of the nozzle, and two or more jets merging in vacuum. Plasma detachment, merging jets temperature and charge state evolution are examined in these processes. High-Z materials, such as argon and xenon, are used throughout these simulations. The plasma moves with an initial velocity of 0-10 km/s (80-100 km/s for jet merging), the initial number density ranges from 10^15cm-3 to 10^18cm-3, and the merging jets are several centimeters in radius. The LSP code is used to perform the simulations using improved fluid algorithms and equation-of-state models from Voss and atomic data from Prism.

  6. [Experimental study on closed plasma discharging under low pressure and spectroscopic diagnosis].

    PubMed

    Lin, Min; Xu, Hao-jun; Su, Chen; Liang, Hua

    2014-06-01

    Closed plasma can overcome difficulties of maintaining plasma and excessive energy consumption in open environment. For plasma stealth technology, a closed plasma generator was designed. Using microsecond pulse generator and argon as working gas, discharge experiments were carried out under low pressure environment. The emission spectrum of Ar at different position in discharge chamber was measured. By using collisional-radiative modal (CRM), the distribution of plasma parameters was studied. At a given electron temperature and density with specified discharge parameters, corresponding population distribution could be obtained by CRM. By comparing the line ratio of argon 2p levels acquired from CRM with the line ratio from spectrum measured, the plasma parameters were confirmed after obtaining the minimum difference value. Using the line ratio of argon 2p9 to 2p1 from CRM while the range of electron density was 1-5 eV, the calculating error was analyzed. The results reveal that, the electron density of the closed plasma reaches a magnitude of 10(11) cm(-3) and shows a gradient distribution with small variational amplitude, and the distribution is beneficial to the application of plasma stealth.

  7. [Experimental study on closed plasma discharging under low pressure and spectroscopic diagnosis].

    PubMed

    Lin, Min; Xu, Hao-jun; Su, Chen; Liang, Hua

    2014-06-01

    Closed plasma can overcome difficulties of maintaining plasma and excessive energy consumption in open environment. For plasma stealth technology, a closed plasma generator was designed. Using microsecond pulse generator and argon as working gas, discharge experiments were carried out under low pressure environment. The emission spectrum of Ar at different position in discharge chamber was measured. By using collisional-radiative modal (CRM), the distribution of plasma parameters was studied. At a given electron temperature and density with specified discharge parameters, corresponding population distribution could be obtained by CRM. By comparing the line ratio of argon 2p levels acquired from CRM with the line ratio from spectrum measured, the plasma parameters were confirmed after obtaining the minimum difference value. Using the line ratio of argon 2p9 to 2p1 from CRM while the range of electron density was 1-5 eV, the calculating error was analyzed. The results reveal that, the electron density of the closed plasma reaches a magnitude of 10(11) cm(-3) and shows a gradient distribution with small variational amplitude, and the distribution is beneficial to the application of plasma stealth. PMID:25358170

  8. Characterization of Wet Air Plasma Jet Powered by Sinusoidal High Voltage and Nanosecond Pulses for Plasma Agricultural Application

    NASA Astrophysics Data System (ADS)

    Takashima, Keisuke; Shimada, Keisuke; Konishi, Hideaki; Kaneko, Toshiro

    2015-09-01

    Not only for the plasma sterilization but also for many of plasma life-science applications, atmospheric pressure plasma devices that allowed us to control its state and reactive species production are deserved to resolve the roles of the chemical species. Influence of the hydroxyl radical and ozone on germination of conidia of a strawberry pathogen is presented. Water addition to air plasma jet significantly improves germination suppression performance, while measured reactive oxygen species (ROS) are reduced. Although the results show a negative correlation between ROS and the germination suppression, this infers the importance of chemical composition generated by plasma. For further control of the plasma product, a plasma jet powered by sinusoidal high voltage and nanosecond pulses is developed and characterized with the voltage-charge Lissajous. Control of breakdown phase and discharge power by pulse-imposed phase is presented. This work is supported by JSPS KAKENHI Grant-in-Aid for Young Scientists (B) Grant Number 15K17480 and Exploratory Research Grant Number 23644199.

  9. Electron scattering by biomass molecular fragments: useful data for plasma applications?*

    NASA Astrophysics Data System (ADS)

    Ridenti, Marco A.; Amorim Filho, Jayr; Brunger, Michael J.; da Costa, Romarly F.; Varella, Márcio T. do N.; Bettega, Márcio H. F.; Lima, Marco A. P.

    2016-08-01

    Recent data obtained for electron scattering by biomass molecular fragments, indicated that low-energy resonances may have an important role in the de-lignification of biomass through a plasma pre-treatment. To support these findings, we present new experimental evidence of the predicted dissociation pathways on plasma treatment of biomass. An important question is how accurate must the experimental and/or the theoretical data be in order to indicate that plasma modelings can be really useful in understanding plasma applications? In this paper, we initiate a discussion on the role of data accuracy of experimental and theoretical electron-molecule scattering cross sections in plasma modeling. First we review technological motivations for carrying out electron-molecule scattering studies. Then we point out the theoretical and experimental limitations that prevent us from obtaining more accurate cross sections. We present a few examples involving biomass molecular fragments, to illustrate theoretical inaccuracies on: resonances positions and widths, electronic excitation, superelastic cross sections from metastable states and due to multichannel effects on the momentum transfer cross sections. On the experimental side we briefly describe challenges in making absolute cross sections measurements with biomass species and radicals. And finally, through a simulation of a N2 plasma, we illustrate the impact on the simulation due to inaccuracies on the resonance positions and widths and due to multichannel effects on the momentum transfer cross sections. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.Supplementary material in the form of one pdf and two mp4 files available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2016-70272-8

  10. Anthem simulational studies of the plasma opening switch

    SciTech Connect

    Mason, R.J.

    1992-01-01

    For a deeper understanding of the physical processes governing the Plasma Opening Switch (POS) we use the ANTHEM 2D implicit simulation code to study: (1) ion dynamical effects on electrohydrodynamic (EHD) waves propagating along steep density interfaces in the switch plasmas. At radial interfaces where the density jumps toward the anode, these waves can drive a finger of magnetic field into the plasma toward the load. Ion dynamics can open the rear of such fingers into a wedge-like density gap. Then: (2) we examine ion effects in uniform switch plasmas. These first develop potential hill structures at the drive edge of the cathode from the competition between electron velocity advection and EHD magnetic exclusion waves. Magnetic pressure gradients at the hill periphery and EHD effects then establish a density gap propagating along the cathode with radial electron emission from its tip. Similar results are obtained under both multi-fluid and PIC modeling of the plasma components.

  11. Anthem simulational studies of the plasma opening switch

    SciTech Connect

    Mason, R.J.

    1992-07-01

    For a deeper understanding of the physical processes governing the Plasma Opening Switch (POS) we use the ANTHEM 2D implicit simulation code to study: (1) ion dynamical effects on electrohydrodynamic (EHD) waves propagating along steep density interfaces in the switch plasmas. At radial interfaces where the density jumps toward the anode, these waves can drive a finger of magnetic field into the plasma toward the load. Ion dynamics can open the rear of such fingers into a wedge-like density gap. Then: (2) we examine ion effects in uniform switch plasmas. These first develop potential hill structures at the drive edge of the cathode from the competition between electron velocity advection and EHD magnetic exclusion waves. Magnetic pressure gradients at the hill periphery and EHD effects then establish a density gap propagating along the cathode with radial electron emission from its tip. Similar results are obtained under both multi-fluid and PIC modeling of the plasma components.

  12. Rapid labeling of lipoproteins in plasma with radioactive cholesterol. Application for measurement of plasma cholesterol esterification

    SciTech Connect

    Yen, F.T.; Nishida, T. )

    1990-02-01

    In order to efficiently and rapidly label lipoproteins in plasma with ({sup 3}H)cholesterol, micelles consisting of lysophosphatidylcholine (lysoPC) and ({sup 3}H)cholesterol (molar ratio, 50:1) were prepared. When trace amounts of these micelles were injected into plasma, ({sup 3}H)cholesterol rapidly equilibrated among the plasma lipoproteins, as compared to ({sup 3}H)cholesterol from an albumin-stabilized emulsion. The distributions of both ({sup 3}H)cholesterol and unlabeled free cholesterol in plasma lipoproteins were similar in labeled plasma samples. This method of labeling can be used for the measurement of cholesterol esterification, or lecithin:cholesterol acyltransferase activity, in small amounts (20-40 microliters) of plasma samples.

  13. Application of Surface Micro-Discharge plasma to spacecraft component decontamination

    NASA Astrophysics Data System (ADS)

    Shimizu, Satoshi; Barczyk, Simon; Rettberg, Petra; Shimizu, Tetsuji; Klaempfl, Tobias; Zimmermann, Julia; Weber, Peter; Morfill, Gregor; Thomas, Hubertus

    2013-09-01

    In the field of extinct or extant extraterrestrial life research on other planets and moons, the prevention of biological contamination through spaceprobes is one of the most important requirements, and its detailed conditions are defined by the COSPAR planetary protection policy. Currently, a dry heat microbial reduction (DHMR) method is the only applicable way to satisfy the demand, which could, however, damage the sophisticated components like integrated circuits. In this study, cold atmospheric plasma based on the Surface Micro-Discharge technology was investigated for inactivation of different types of bacteria and endospores as an alternative method. After 90 min of plasma gas exposure, 3-6 log reductions were observed for the vegetative bacteria Escherichia coliand Deinococcus radiodurans and several types of bacterial endospores - including Bacillus atrophaeus, B. safensis, B. megaterium, B. megaterium 2c1 and B. thuringiensis E24. Furthermore, the applicability of the system for spacecraft decontamination was checked by studying the inactivation homogeneity, the temperature at the area of interest and the effects of the plasma gas exposure on different materials. The authors would like to acknowledge the financial support from Deutches Zentrum fuer Luft- und Raumfahrt (FKZ 50 JR1005).

  14. Guest investigator program study: Physics of equatorial plasma bubbles

    NASA Technical Reports Server (NTRS)

    Tsunoda, Roland T.

    1994-01-01

    Plasma bubbles are large-scale (10 to 100 km) depletions in plasma density found in the night-time equatorial ionosphere. Their formation has been found to entail the upward transport of plasma over hundreds of kilometers in altitude, suggesting that bubbles play significant roles in the physics of many of the diverse and unique features found in the low-latitude ionosphere. In the simplest scenario, plasma bubbles appear first as perturbations in the bottomside F layer, which is linearly unstable to the gravitationally driven Rayleigh-Taylor instability. Once initiated, bubbles develop upward through the peak of the F layer into its topside (sometimes to altitudes in excess of 1000 km), a behavior predicted by the nonlinear form of the same instability. While good general agreement has been found between theory and observations, little is known about the detailed physics associated with plasma bubbles. Our research activity centered around two topics: the shape of plasma bubbles and associated electric fields, and the day-to-day variability in the occurrence of plasma bubbles. The first topic was pursued because of a divergence in view regarding the nonlinear physics associated with plasma bubble development. While the development of perturbations in isodensity contours in the bottomside F layer into plasma bubbles is well accepted, some believed bubbles to be cylinder-like closed regions of depleted plasma density that floated upward leaving a turbulent wake behind them (e.g., Woodman and LaHoz, 1976; Ott, 1978; Kelley and Ott, 1978). Our results, summarized in a paper submitted to the Journal of Geophysical Research, consisted of incoherent scatter radar measurements that showed unambiguously that the depleted region is wedgelike and not cylinderlike, and a case study and modeling of SM-D electric field instrument (EFI) measurements that showed that the absence of electric-field perturbations outside the plasma-depleted region is a distinct signature of wedge

  15. Investigations of Remote Plasma Irregularites by Radio Sounding: Applications of the Radio Plasma Imager on IMAGE

    NASA Technical Reports Server (NTRS)

    Fung, Shing F.; Benson, Robert F.; Carpenter, Donald L.; Reinsch, Bodo W.; Gallagher, Dennis L.

    1999-01-01

    The Radio Plasma Imager (RPI) on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission operates like a radar by transmitting and receiving coherent electromagnetic pulses. Long-range echoes of electromagnetic sounder waves are reflected at remote plasma cutoffs. Thus, analyses of RPI observations will yield the plasma parameters and distances to the remote reflection points. These analyses assume that the reflecting plasma surfaces are cold and are sufficiently smooth that they effectively behave as plane mirrors to the incoming sounder waves, i.e., that geometric optics can be used. The RPI will employ pulse compression and spectral integration techniques, perfected in ground-based ionospheric digital sounders, in order to enhance the signal-to-noise ratio in long-range magnetospheric sounding. When plasma irregularities exist in the remote magnetospheric plasmas that are being probed by the sounder waves, echo signatures may become complicated. Ionospheric sounding experience indicates that while topside sounding echo strengths can actually be enhanced by the presence of irregularities, ground-based sounding indicates that coherent detection techniques can still be employed. In this paper we investigate the plasma conditions that will allow coherent signals to be detected by the RPI and the signatures to be expected, such as scattering and plasma resonances, in the presence of multi-scale irregularities, may possibly have on RPI signals. Sounding of irregular plasma structures in the plasmasphere, plasmapause and magnetopause are also discussed.

  16. Radiating plasma species density distribution in EUV-induced plasma in argon: a spatiotemporal experimental study

    NASA Astrophysics Data System (ADS)

    van der Horst, R. M.; Beckers, J.; Osorio, E. A.; van de Ven, T. H. M.; Banine, V. Y.

    2015-12-01

    In this contribution we experimentally study temporally and spatially resolved radiating plasma species density distribution in plasma induced by irradiating a low pressure argon gas with high energy photons with a wavelength of 13.5 nm, i.e. extreme ultraviolet (EUV). This is done by recording the optical emission spatially and temporally resolved by an iCCD camera as a function of the argon gas pressure. Our experimental results show that the emission intensity, i.e. density of radiating plasma species, depends quadratically on the gas pressure. The linear term is due to photoionization and simultaneous excitation by EUV photons, the quadratic term due to electron impact excitation by electrons generated by photoionization. The decay of radiating plasma species can be divided into two phases. At time scales shorter than 10 μs (first phase), the decay is governed by radiative decay of radiating plasma species. At longer time scales (second phase, >10 μs), the decay is dominated by diffusion and subsequent de-excitation at the wall. The experimental decay and expansion during this phase corresponds well with a simplified diffusion model. In order to gain more insight in this exotic type of plasma, we compare the electron density from previous measurements with the results obtained here.

  17. Extended plasma channels created by UV laser in air and their application to control electric discharges

    NASA Astrophysics Data System (ADS)

    Zvorykin, V. D.; Ionin, A. A.; Levchenko, A. O.; Seleznev, L. V.; Sinitsyn, D. V.; Smetanin, I. V.; Ustinovskii, N. N.; Shutov, A. V.

    2015-02-01

    Results are presented from a series of experimental and theoretical studies on creating weakly ionized extended plasma channels in atmospheric air by 248-nm UV laser radiation and their application to control long high-voltage discharges. The main mechanisms of air ionization by UV laser pulses with durations from 100 fs to 25 ns and intensities in the ranges of 3×1011-1.5×1013 and 3×106-3×1011 W/cm2, respectively, which are below the threshold for optical gas breakdown, as well as the main relaxation processes in plasma with a density of 109-1017 cm-3, are considered. It is shown that plasma channels in air can be efficiently created by amplitude-modulated UV pulses consisting of a train of subpicosecond pulses producing primary photoelectrons and a long UV pulse suppressing electron attachment and sustaining the density of free electrons in plasma. Different modes of the generation and amplification of trains of subterawatt subpicosecond pulses and amplitude-modulated UV pulses with an energy of several tens of joules were implemented on the GARPUN-MTW hybrid Ti:sapphire-KrF laser facility. The filamentation of such UV laser beams during their propagation in air over distances of up to 100 m and the parameters of the corresponding plasma channels were studied experimentally and theoretically. Laser initiation of high-voltage electric discharges and control of their trajectories by means of amplitude-modulated UV pulses, as well as the spatiotemporal structure of breakdowns in air gaps with length of up to 80 cm, were studied.

  18. Extended plasma channels created by UV laser in air and their application to control electric discharges

    SciTech Connect

    Zvorykin, V. D. Ionin, A. A.; Levchenko, A. O.; Seleznev, L. V.; Sinitsyn, D. V.; Smetanin, I. V.; Ustinovskii, N. N.; Shutov, A. V.

    2015-02-15

    Results are presented from a series of experimental and theoretical studies on creating weakly ionized extended plasma channels in atmospheric air by 248-nm UV laser radiation and their application to control long high-voltage discharges. The main mechanisms of air ionization by UV laser pulses with durations from 100 fs to 25 ns and intensities in the ranges of 3×10{sup 11}–1.5×10{sup 13} and 3×10{sup 6}–3×10{sup 11} W/cm{sup 2}, respectively, which are below the threshold for optical gas breakdown, as well as the main relaxation processes in plasma with a density of 10{sup 9}–10{sup 17} cm{sup −3}, are considered. It is shown that plasma channels in air can be efficiently created by amplitude-modulated UV pulses consisting of a train of subpicosecond pulses producing primary photoelectrons and a long UV pulse suppressing electron attachment and sustaining the density of free electrons in plasma. Different modes of the generation and amplification of trains of subterawatt subpicosecond pulses and amplitude-modulated UV pulses with an energy of several tens of joules were implemented on the GARPUN-MTW hybrid Ti:sapphire-KrF laser facility. The filamentation of such UV laser beams during their propagation in air over distances of up to 100 m and the parameters of the corresponding plasma channels were studied experimentally and theoretically. Laser initiation of high-voltage electric discharges and control of their trajectories by means of amplitude-modulated UV pulses, as well as the spatiotemporal structure of breakdowns in air gaps with length of up to 80 cm, were studied.

  19. Study of Plasma Liner Driven Magnetized Target Fusion Via Advanced Simulations

    SciTech Connect

    Samulyak, Roman V.; Parks, Paul

    2013-08-31

    The feasibility of the plasma liner driven Magnetized Target Fusion (MTF) via terascale numerical simulations will be assessed. In the MTF concept, a plasma liner, formed by merging of a number (60 or more) of radial, highly supersonic plasma jets, implodes on the target in the form of two compact plasma toroids, and compresses it to conditions of the fusion ignition. By avoiding major difficulties associated with both the traditional laser driven inertial confinement fusion and solid liner driven MTF, the plasma liner driven MTF potentially provides a low-cost and fast R&D path towards the demonstration of practical fusion energy. High fidelity numerical simulations of full nonlinear models associated with the plasma liner MTF using state-of-art numerical algorithms and terascale computing are necessary in order to resolve uncertainties and provide guidance for future experiments. At Stony Brook University, we have developed unique computational capabilities that ideally suite the MTF problem. The FronTier code, developed in collaboration with BNL and LANL under DOE funding including SciDAC for the simulation of 3D multi-material hydro and MHD flows, has beenbenchmarked and used for fundamental and engineering problems in energy science applications. We have performed 3D simulations of converging supersonic plasma jets, their merger and the formation of the plasma liner, and a study of the corresponding oblique shock problem. We have studied the implosion of the plasma liner on the magnetized plasma target by resolving Rayleigh-Taylor instabilities in 2D and 3D and other relevant physics and estimate thermodynamic conditions of the target at the moment of maximum compression and the hydrodynamic efficiency of the method.

  20. Studies of cryogenic electron plasmas in magnetic mirror fields

    NASA Astrophysics Data System (ADS)

    Gopalan, Ramesh

    This thesis considers the properties of pure electron plasmas in Penning traps which have an axially varying magnetic field. Our theory of the thermal equilibrium of such plasmas in magnetic mirror fields indicates that their behavior may be characterized by the ratio of their temperature to their central density T/n. For cold, dense plasmas the density along the plasma axis scales linearly with the magnetic field, while for hot, tenuous plasmas, at the opposite limit of the parameter range, the density is constant along the axis, similar to the behavior of a neutral plasma in a magnetic mirror. We are able to conclude from this that the electrostatic potential varies along the field lines, in equilibrium. As the plasma charge and potential distribution must be consistent with the grounded potential on the trap walls, the plasma profile does not follow the geometry of the magnetic field lines; the plasma radius in the high-field region is smaller than would be obtained by mapping the field lines from the radial edge of the low-field region. Another interesting feature of these mirror equilibria is that there are trapped populations of particles both in the low-field and high-field regions. Our experiments on the Cryogenic Electron Trap have confirmed many of these theoretical results over a wide parameter range. We have been able to sample the volume charge density at various points on the axis. We have also measured the line-charge distribution of the plasma. Both these experiments are in general agreement with our theory of the global thermal equilibrium in the mirror- field. A surprising observation has been the unexpectedly long- life of the m = 1 diocotron mode in these traps where the magnetic field varies by ~100% across its length. We report these observations, along with plausible explanations for them. The trap we have constructed is intended for the eventual study of very cold electron plasmas in strong magnetic fields, where the plasma electrons are

  1. Vacuum Plasma Spray (VPS) Material Applications for Thruster Components

    NASA Technical Reports Server (NTRS)

    Elam, Sandra; Holmes, Richard; Hickman, Robert

    2006-01-01

    A variety of vacuum plasma spray (VPS) material systems have been successfully applied to injector and thrust chamber components. VPS offers a versatile fabrication process with relatively low costs to produce near net shape parts. The materials available with VPS increase operating margins and improve component life by providing superior thermal and oxidation protection in specific engine environments. Functional gradient materials (FGM) formed with VPS allow thrust chamber liners to be fabricated with GRCop-84 (an alloy of copper, chrome, and niobium) and a protective layer of NiCrAlY on the hot wall. A variety of thrust chamber liner designs have been fabricated to demonstrate the versatility of the process. Hot-fire test results have confined the improved durability and high temperature performance of the material systems for thrust chamber liners. Similar FGM s have been applied to provide superior thermal protection on injector faceplates with NiCrAlY and zirconia coatings. The durability of the applied materials has been demonstrated with hot-fire cycle testing on injector faceplates in high temperature environments. The material systems can benefit the components used in booster and main engine propulsion systems. More recent VPS efforts are focused on producing rhenium based material systems for high temperature applications to benefit in-space engines like reaction control system (RCS) thrusters.

  2. Vacuum Plasma Spray (VPS) Material Applications for Thruster Components

    NASA Technical Reports Server (NTRS)

    Elam, Sandra; Holmes, Richard; Hickman, Robert

    2006-01-01

    A variety of vacuum plasma spray (VPS) material systems have been successfully applied to injector and thrust chamber components. VPS offers a versatile fabrication process with relatively low costs to produce near net shape parts. The materials available with VPS increase operating margins and improve component life by providing superior thermal and oxidation protection in specific engine environments. Functional gradient materials (FGM) formed with VPS allow thrust chamber liners to be fabricated with GRCop-84 (an alloy of copper, chrome, and niobium) and a protective layer of NiCrAlY on the hot wall. A variety of thrust chamber liner designs have been fabricated to demonstrate the versatility of the process. Hot-fire test results have confirmed the improved durability and high temperature performance of the material systems for thrust chamber liners. Similar FGM s have been applied to provide superior thermal protection on injector faceplates with NiCrAlY and zirconia coatings. The durability of the applied materials has been demonstrated with hot-fire cycle testing on injector faceplates in high temperature environments. The material systems can benefit the components used in booster and main engine propulsion systems. More recent VPS efforts are focused on producing rhenium based material systems for high temperature applications to benefit in-space engines like reaction control system (RCS) thrusters.

  3. Simultaneous determination of parecoxib sodium and its active metabolite valdecoxib in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study after intravenous and intramuscular administration.

    PubMed

    Liu, Meina; Yu, Qiuyang; Li, Ping; Zhu, Meng; Fang, Mingming; Sun, Bingjun; Sun, Mengchi; Sun, Yinghua; Zhang, Peng; He, Zhonggui; Sun, Jin; Wang, Yongjun; Liu, Xiaohong

    2016-06-01

    In this study, we developed and validated a new, rapid, specific and sensitive ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method to simultaneously determine parecoxib sodium (PX) and its active metabolite, valdecoxib (VX), in rat plasma. Plasma samples were prepared by plasma protein precipitation combined with a liquid-liquid extraction method. The separation was carried out on a Kinetex C18 column (2.1mm×50mm, 2.6μm) with a gradient elution using methanol (A) and a 2mM ammonium acetate aqueous solution (B). The analysis was performed in less than 3min with a flow rate of 0.2mL/min. Ketoprofen was used as an internal standard (IS). Mass spectrometric detection was conducted with a triple quadrupole detector equipped with electrospray ionization in the negative ion mode (ESI(-)) using multiple reaction monitoring (MRM). The calibration curves were linear over the concentration ranges of 5-4000ng/mL for PX and 5-2000ng/mL for VX with all correlation coefficients greater than 0.998. The intra- and inter-day relative standard deviations (RSD) for both analytes were within 15% and the accuracy was within 85-115% at all quality control levels. The mean extraction recoveries for all analytes obtained from three concentrations of QC plasma samples were more than 89.0% efficient. Selectivity, matrix effect, dilution integrity and stability were also validated. The method was successfully used to investigate the pharmacokinetics of PX and VX in rat plasma after intravenous and intramuscular administration of PX. PMID:27107851

  4. Development and validation of an HPLC-UV method for simultaneous determination of zidovudine, lamivudine, and nevirapine in human plasma and its application to pharmacokinetic study in human volunteers.

    PubMed

    Nandi, Utpal; Das, Ayan; Roy, Bikash; Choudhury, Hira; Gorain, Bapi; Pal, Tapan Kumar

    2013-06-01

    A simple, rapid, and sensitive high performance liquid chromatographic method with UV detection has been developed and validated according to the FDA guidelines for the quantitation of zidovudine (ZDV), lamivudine (LMV), and nevirapine (NVR) in human plasma. The sample was prepared by simple liquid-liquid extraction. Chromatographic separation was carried out in a Hypersil BDS, C(18) column (250 mm × 4.6 mm; 5 µm particle size) with simple mobile phase composition of 0.1 M ammonium acetate buffer in 0.5% acetic acid, v/v and methanol (40:60, v/v) at a flow rate of 0.85 ml min(-1) where detector was set at 270 nm with a total run time of 10 min which is very short for simultaneous estimation of three analytes in plasma. The method was linear over the concentration range of 50-3000, 50-2000 and 10-3000 ng ml(-1) with lower limit of quantifications (LLOQ) of 50, 50, and 10 ng ml(-1) for ZDV, LMV, and NVR, respectively. Accuracy and precision values of both within-run and between-run obtained from six different sets of three quality control (QC) samples along with the LLOQ analyzed in separate occasions for all the analytes ranged from 94.47-99.71% and 0.298-3.507%, respectively. Extraction recovery of analytes in plasma samples was above 90.16%. In stability tests, all the analytes in human plasma were stable during storage and assay procedure. The developed and validated method was successfully applied to quantitative determination of the three analytes in plasma for pharmacokinetic study in 12 healthy human volunteers. PMID:22374835

  5. Plasma buprenorphine concentrations after the application of a 70 microg/h transdermal patch in dogs. Preliminary report.

    PubMed

    Andaluz, A; Moll, X; Ventura, R; Abellán, R; Fresno, L; García, F

    2009-10-01

    The objective of the present study was to evaluate the plasma concentrations and pharmacokinetics of buprenorphine after transdermal application in dogs (n = 4). A 70 microg/h transdermal buprenorphine patch was applied to the ventral abdomen of four healthy beagles. Blood samples were collected through a preplaced jugular catheter before and at 1, 2, 4, 8, 12, 24, 36, 48 and every 6 h until 108 h after the patch application. Plasma buprenorphine concentrations were measured using a (125)I-labelled radioimmunoassay (RIA) assay. No adverse effects were observed in any of the dogs. Concentrations of buprenorphine were detected in plasma after the application of the transdermal buprenorphine patch on the four experimental animals. Buprenorphine plasma concentrations increased during the first 36 h and then remained in the 0.7-1.0 ng/mL range during the study period. A decrease in plasma buprenorphine concentration was not observed during the study. Although analgesia could not be demonstrated the present study shows the ability of buprenorphine transdermal delivery systems developed for human use to deliver measurable concetrations of buprenorphine in dogs.

  6. Dielectric covered hairpin probe for its application in reactive plasmas

    NASA Astrophysics Data System (ADS)

    Gogna, G. S.; Gaman, C.; Karkari, S. K.; Turner, M. M.

    2012-07-01

    The hairpin probe is a well known technique for measuring local electron density in low temperature plasmas. In reactive plasmas, the probe characteristics are affected by surface sputtering, contamination, and secondary electron emission. At higher densities, the plasma absorbs the entire electromagnetic energy of hairpin and hence limits the density measurements. These issues can be resolved by covering the hairpin surface with a thin layer of dielectric. In this letter, the dielectric contribution to the probe characteristics is incorporated in a theory which is experimentally verified. The dielectric covering improves the performance of probe and also allows the hairpin tip to survive in reactive plasma where classical electrical probes are easily damaged.

  7. Applications of numerical codes to space plasma problems

    NASA Technical Reports Server (NTRS)

    Northrop, T. G.; Birmingham, T. J.; Jones, F. C.; Wu, C. S.

    1975-01-01

    Solar wind, earth's bowshock, and magnetospheric convection and substorms were investigated. Topics discussed include computational physics, multifluid codes, ionospheric irregularities, and modeling laser plasmas.

  8. Plasma technologies application for building materials surface modification

    NASA Astrophysics Data System (ADS)

    Volokitin, G. G.; Skripnikova, N. K.; Volokitin, O. G.; Shehovtzov, V. V.; Luchkin, A. G.; Kashapov, N. F.

    2016-01-01

    Low temperature arc plasma was used to process building surface materials, such as silicate brick, sand lime brick, concrete and wood. It was shown that building surface materials modification with low temperature plasma positively affects frost resistance, water permeability and chemical resistance with high adhesion strength. Short time plasma processing is rather economical than traditional processing thermic methods. Plasma processing makes wood surface uniquely waterproof and gives high operational properties, dimensional and geometrical stability. It also increases compression resistance and decreases inner tensions level in material.

  9. Application of cylindrical Langmuir probes to streaming plasma diagnostics.

    NASA Technical Reports Server (NTRS)

    Segall, S. B.; Koopman, D. W.

    1973-01-01

    The current-voltage characteristics of cylindrical probes in a high velocity collisionless plasma flow have been investigated experimentally and theoretically. The plasma was generated by a focused laser pulse incident on a metallic target in vacuum. An analysis, developed from a stationary plasma analog to the flowing case, demonstrated a failure of plasma shielding of probe potential in the electron attracting region. Modifications of relatively simple previous treatments were found to be valid for computing electron current to a probe. The electron characteristics derived from the present analysis agree well with experimental results. The ion and electron portions of the characteristics are consistent with each other and with independent diagnostic measurements.

  10. Hybrid Model of Inhomogeneous Solar Wind Plasma Heating by Alfven Wave Spectrum: Parametric Studies

    NASA Technical Reports Server (NTRS)

    Ofman, L.

    2010-01-01

    Observations of the solar wind plasma at 0.3 AU and beyond show that a turbulent spectrum of magnetic fluctuations is present. Remote sensing observations of the corona indicate that heavy ions are hotter than protons and their temperature is anisotropic (T(sub perpindicular / T(sub parallel) >> 1). We study the heating and the acceleration of multi-ion plasma in the solar wind by a turbulent spectrum of Alfvenic fluctuations using a 2-D hybrid numerical model. In the hybrid model the protons and heavy ions are treated kinetically as particles, while the electrons are included as neutralizing background fluid. This is the first two-dimensional hybrid parametric study of the solar wind plasma that includes an input turbulent wave spectrum guided by observation with inhomogeneous background density. We also investigate the effects of He++ ion beams in the inhomogeneous background plasma density on the heating of the solar wind plasma. The 2-D hybrid model treats parallel and oblique waves, together with cross-field inhomogeneity, self-consistently. We investigate the parametric dependence of the perpendicular heating, and the temperature anisotropy in the H+-He++ solar wind plasma. It was found that the scaling of the magnetic fluctuations power spectrum steepens in the higher-density regions, and the heating is channeled to these regions from the surrounding lower-density plasma due to wave refraction. The model parameters are applicable to the expected solar wind conditions at about 10 solar radii.

  11. Application of a novel liquid chromatography/tandem mass spectrometry method for the determination of antazoline in human plasma: Result of ELEPHANT-I [ELEctrophysiological, pharmacokinetic and hemodynamic effects of PHenazolinum (ANTazoline mesylate)] human pharmacokinetic study.

    PubMed

    Giebułtowicz, Joanna; Piotrowski, Roman; Baran, Jakub; Kułakowski, Piotr; Wroczyński, Piotr

    2016-05-10

    Antazoline is a first-generation antihistaminic agent with antiarrhythmic quinidine-like properties. In some countries, it is widely used for termination of cardiac arrhythmias, especially atrial fibrillation (AF). However, no human pharmacokinetic studies have been conducted with intravenous antazoline. The aim of our study was to develop and validate a novel liquid chromatography/tandem mass spectrometry (LC-MS/MS) method for the determination of antazoline in human plasma: the ELEPHANT-I [ELEctrophysiological, pharmacokinetic and hemodynamic effects of PHenazolinum (ANTazoline mesylate)] human pharmacokinetic study. Antazoline was extracted from plasma using liquid-liquid extraction. The concentration of the analyte was measured by LC-MS/MS with xylometazoline as an internal standard. The method was validated for linearity, precision, accuracy, stability (freeze/thaw stability, stability in autosampler, short and long term stability), dilution integrity and matrix effect. The analyzed validation criteria were fulfilled. The method was applied to a pharmacokinetic study involving 10 healthy volunteers. Following a single intravenous dose of antazoline mesylate (100 mg), the plasma concentration profile showed a relative fast elimination with a terminal elimination half-life of 2.29 h. A relatively high volume of distribution was observed (Vss=315 L). The values of mean residence time (MRT∞), area under the curve (AUC∞) and clearance were 3.45 h, 0.91 mg h L(-1) and 80.5 L h(-1), respectively. One volunteer showed significant differences in pharmacokinetic parameters. In conclusion, the proposed new LC-MS/MS method was successfully used for the first time for the determination of antazoline in human plasma. PMID:26895496

  12. Brightness enhancement of plasma ion source by utilizing anode spot for nano applications.

    PubMed

    Park, Yeong-Shin; Lee, Yuna; Kim, Yoon-Jae; Park, Man-Jin; Moon, Dae Won; Chung, Kyoung-Jae; Hwang, Y S

    2012-02-01

    Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with∕without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12,300 A∕m(2) SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

  13. Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

    SciTech Connect

    Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, Yoon-Jae; Park, Man-Jin; Moon, Dae Won

    2012-02-15

    Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m{sup 2} SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

  14. Feasibility study of plasma sprayed Al2O3 coatings as diffusion barrier on CFC components

    NASA Astrophysics Data System (ADS)

    Bobzin, Kirsten; Zhao, Lidong; Kopp, Nils; Warda, Thomas

    2012-12-01

    Carbon fibre reinforced carbon (CFC) materials are increasingly applied as sample carriers in modern furnaces. Only their tendency to react with different metals at high temperatures by C-diffusion is a disadvantage, which can be solved by application of diffusion barriers. Within this study the feasibility of plasma sprayed Al2O3 coatings as diffusion barrier was studied. Al2O3 coatings were prepared by air plasma spraying (APS). The coatings were investigated in terms of their microstructure, bonding to CFC substrates and thermal stability. The results showed that Al2O3 could be well deposited onto CFC substrates. The coatings had a good bonding and thermal shock behavior at 1060°C. At higher temperature of 1270°C, crack network formed within the coating, showing that the plasma sprayed Al2O3 coatings are limited regarding to their application temperatures as diffusion barrier on CFC components.

  15. Study of electrical resistivity and thermal conductivity into neutral plasma

    SciTech Connect

    Nath, G. Rout, R. K.

    2015-07-31

    The major portion of the bulk plasma in magnetospheric space, interplanetary plasma belts and the solar winds contain neutral particles. Evidently these neutral particles undergo binary collisions with the charged particles and among themselves so as to contribute significantly to the transport and diffusion process in a singly charged electron – ion magnetoplasma. The effects of the neutral particles collisions on various diffusion transport coefficients are studied for magnetised electron-ion plasma and appropriately modified coefficients are derived analytically. The results reveal that these coefficients increase significantly owing to the effect of the charge -neutral and neutral-neutral collisions.

  16. Molecular dynamic study of pressure fluctuations spectrum in plasma

    NASA Astrophysics Data System (ADS)

    Bystryi, R. G.

    2015-11-01

    Pressure of plasma is calculated by using classical molecular dynamics method. The formula based on virial theorem was used. Spectrum pressure's fluctuations of singly ionized non-ideal plasma are studied. 1/f-like spectrum behavior is observed. In other words, flicker noise is observed in fluctuations of pressure equilibrium non-ideal plasma. Relations between the obtained result and pressure fluctuations within the Gibbs and Einstein approaches are discussed. Special attention is paid to features of calculating the pressure in strongly coupled systems.

  17. Effects of a Nonthermal Atmospheric Pressure Plasma Jet on Human Gingival Fibroblasts for Biomedical Application

    PubMed Central

    2016-01-01

    Nonthermal atmospheric pressure plasma jets (APPJ) have been developed and applied in biomedical research as a cancer treatment or bacterial sterilization. However, the drawback of APPJ on normal oral cells during plasma treatment and underlying cell death mechanisms have not been studied and clearly explained, although there is known to be an influence from reactive oxygen species (ROS). Hence, this study investigates whether and how a nonthermal atmospheric pressure air plasma jet kills human normal gingival cells using immortalized human gingival fibroblasts (hTERT-hNOF cells). In this study, a set of physicochemical or biological methods were used to illuminate the killing mechanisms. It was found that ROS were induced intracellularly without a breakdown of the cell wall and apoptosis was involved in cell death when an air APPJ treatment was performed on the cells directly without media; the air treatment only supported a detachment of the cells without increase of ROS. It was also revealed that a correlation between intracellular ROS concentration and cells viability existed. These results indicated that the direct air APPJ treatment possibly raises safety issue to normal tissue and thereby APPJ application in biomedical field needs more in vitro and in vivo study to optimize it.

  18. Effects of a Nonthermal Atmospheric Pressure Plasma Jet on Human Gingival Fibroblasts for Biomedical Application.

    PubMed

    Lee, Jung-Hwan; Kim, Kyoung-Nam

    2016-01-01

    Nonthermal atmospheric pressure plasma jets (APPJ) have been developed and applied in biomedical research as a cancer treatment or bacterial sterilization. However, the drawback of APPJ on normal oral cells during plasma treatment and underlying cell death mechanisms have not been studied and clearly explained, although there is known to be an influence from reactive oxygen species (ROS). Hence, this study investigates whether and how a nonthermal atmospheric pressure air plasma jet kills human normal gingival cells using immortalized human gingival fibroblasts (hTERT-hNOF cells). In this study, a set of physicochemical or biological methods were used to illuminate the killing mechanisms. It was found that ROS were induced intracellularly without a breakdown of the cell wall and apoptosis was involved in cell death when an air APPJ treatment was performed on the cells directly without media; the air treatment only supported a detachment of the cells without increase of ROS. It was also revealed that a correlation between intracellular ROS concentration and cells viability existed. These results indicated that the direct air APPJ treatment possibly raises safety issue to normal tissue and thereby APPJ application in biomedical field needs more in vitro and in vivo study to optimize it.

  19. Effects of a Nonthermal Atmospheric Pressure Plasma Jet on Human Gingival Fibroblasts for Biomedical Application

    PubMed Central

    2016-01-01

    Nonthermal atmospheric pressure plasma jets (APPJ) have been developed and applied in biomedical research as a cancer treatment or bacterial sterilization. However, the drawback of APPJ on normal oral cells during plasma treatment and underlying cell death mechanisms have not been studied and clearly explained, although there is known to be an influence from reactive oxygen species (ROS). Hence, this study investigates whether and how a nonthermal atmospheric pressure air plasma jet kills human normal gingival cells using immortalized human gingival fibroblasts (hTERT-hNOF cells). In this study, a set of physicochemical or biological methods were used to illuminate the killing mechanisms. It was found that ROS were induced intracellularly without a breakdown of the cell wall and apoptosis was involved in cell death when an air APPJ treatment was performed on the cells directly without media; the air treatment only supported a detachment of the cells without increase of ROS. It was also revealed that a correlation between intracellular ROS concentration and cells viability existed. These results indicated that the direct air APPJ treatment possibly raises safety issue to normal tissue and thereby APPJ application in biomedical field needs more in vitro and in vivo study to optimize it. PMID:27597959

  20. Effects of a Nonthermal Atmospheric Pressure Plasma Jet on Human Gingival Fibroblasts for Biomedical Application.

    PubMed

    Lee, Jung-Hwan; Kim, Kyoung-Nam

    2016-01-01

    Nonthermal atmospheric pressure plasma jets (APPJ) have been developed and applied in biomedical research as a cancer treatment or bacterial sterilization. However, the drawback of APPJ on normal oral cells during plasma treatment and underlying cell death mechanisms have not been studied and clearly explained, although there is known to be an influence from reactive oxygen species (ROS). Hence, this study investigates whether and how a nonthermal atmospheric pressure air plasma jet kills human normal gingival cells using immortalized human gingival fibroblasts (hTERT-hNOF cells). In this study, a set of physicochemical or biological methods were used to illuminate the killing mechanisms. It was found that ROS were induced intracellularly without a breakdown of the cell wall and apoptosis was involved in cell death when an air APPJ treatment was performed on the cells directly without media; the air treatment only supported a detachment of the cells without increase of ROS. It was also revealed that a correlation between intracellular ROS concentration and cells viability existed. These results indicated that the direct air APPJ treatment possibly raises safety issue to normal tissue and thereby APPJ application in biomedical field needs more in vitro and in vivo study to optimize it. PMID:27597959

  1. Surface Modification of Graphene Oxides by Plasma Techniques and Their Application for Environmental Pollution Cleanup.

    PubMed

    Wang, Xiangxue; Fan, Qiaohui; Chen, Zhongshan; Wang, Qi; Li, Jiaxing; Hobiny, Aatef; Alsaedi, Ahmed; Wang, Xiangke

    2016-02-01

    Graphene oxides (GOs) have come under intense multidisciplinary study because of their unique physicochemical properties and possible applications. The large amount of oxygen-containing functional groups on GOs leads to a high sorption capacity for the removal of various kinds of organic and inorganic pollutants from aqueous solutions in environmental pollution cleanup. However, the lack of selectivity results in difficulty in the selective removal of target pollutants from aqueous solutions in the presence of other coexisting pollutants. Herein, the surface grafting of GOs with special oxygen-containing functional groups using low-temperature plasma techniques and the application of the surface-modified GOs for the efficient removal of organic and inorganic pollutants in environmental pollution are reviewed. This paper gives an account of our research on the application of GO-based nanomaterials in environmental pollution cleanup, including: (1) the synthesis and surface grafting of functional groups on GOs, summarizing various types of low-temperature plasma techniques for the synthesis of graphene/GOs; and (2) the application of graphene/GOs and their composites for the efficient removal of organic and inorganic pollutants from aqueous solutions, including the interaction mechanism according to recently published results.

  2. Cavitational Iron Microparticles Generation By Plasma Procedures For Medical Applications

    NASA Astrophysics Data System (ADS)

    Bica, Ioan; Bunoiu, Madalin; Chirigiu, Liviu; Spunei, Marius; Juganaru, Iulius

    2012-12-01

    The paper presents the experimental installation for the production, in argon plasma, of cavitational iron microparticles (pore microspheres, microtubes and octopus-shaped microparticles). Experimental results are presented and discussed and it is shown that absorbant particles with a minimum iron content are obtained by the plasma procedures

  3. Unified first wall - blanket structure for plasma device applications

    DOEpatents

    Gruen, D.M.

    A plasma device is described for use in controlling nuclear reactions within the plasma including a first wall and blanket formed in a one-piece structure composed of a solid solution containing copper and lithium and melting above about 500/sup 0/C.

  4. On the classification of dielectric barrier discharge plasma actuators: A comprehensive performance evaluation study

    NASA Astrophysics Data System (ADS)

    Kriegseis, J.; Duchmann, A.; Tropea, C.; Grundmann, S.

    2013-08-01

    The increasing popularity and maturity of plasma actuators for many flow control applications requires a common standard for plasma actuator performance evaluation. In the present work, a comprehensive comparative study of existing and new evaluation measures is presented, based on results from identical plasma-actuator configurations. A power-flow diagram is introduced that covers the entire range of power stages from the energy source to the flow-control success. All individual power stages are explained, existing controversial definitions are clarified, and an evaluation guideline is applied to previously obtained data. Finally, the defined systematic analysis is applied to the results of a recently conducted plasma-actuator in-flight experiment.

  5. Probes for edge plasma studies of TFTR (invited)

    NASA Astrophysics Data System (ADS)

    Manos, D. M.; Budny, R. V.; Kilpatrick, S.; Stangeby, P.; Zweben, S.

    1986-08-01

    Tokamak fusion test reactor (TFTR) probes are designed to study the interaction of the plasma with material surfaces such as the wall and limiters, and to study the transport of particles and energy between the core and edge. Present probe heads have evolved from prototypes in Princeton large torus (PLT), poloidal divertor experiment (PDX) [Princeton BETA experiment (PBX)], and the initial phase of TFTR operation. The newest heads are capable of making several simultaneous measurements and include Langmuir probes, heat flux probes, magnetic coils, rotating calorimeter fast ion probes, and sample exposure specimens. This paper describes these probe heads and presents some of the data they and their prototypes have acquired. The paper emphasizes measurement of transient plasma effects such as fast ion loss during auxiliary heating, the evolution of the edge plasma during heating, compression, and free expansion, and fluctuations in the edge plasma.

  6. BOOK REVIEW: Introduction to Plasma Physics: With Space and Laboratory Applications

    NASA Astrophysics Data System (ADS)

    Browning, P. K.

    2005-07-01

    A new textbook on plasma physics must be very welcome, as this will encourage the teaching of courses on the subject. This book is written by two experts in their fields, and is aimed at advanced undergraduate and postgraduate courses. There are of course many other plasma physics textbooks available. The niche which this particular book fills is really defined by its subtitle: that is, `with space and laboratory applications'. This differs from most other books which tend to emphasise either space or fusion applications (but not both) or to concentrate only on general theory. Essentially, the emphasis here is on fundamental plasma physics theory, but applications are given from time to time. For example, after developing Alfvén wave theory, observations of Alfvén waves in the solar wind and in the Jovian magnetosphere are presented; whilst ion acoustic cylcotron waves are illustrated by data from a laboratory Q machine. It is fair to say that examples from space seem to predominate. Nevertheless, the approach of including a broad range of applications is very good from an educational point of view, and this should help to train a generation of students with a grasp of fundamental plasma physics who can work in a variety of research fields. The subject coverage of the book is fairly conventional and there are no great surprises. It begins, inevitably, with a discussion of plasma parameters (Debye length etc) and of single particle motions. Both kinetic theory and magnetohydrodynamics are introduced. Waves are quite extensively discussed in several chapters, including both cold and hot plasmas, magnetised and unmagnetised. Nonlinear effects—a large subject!—are briefly discussed. A final chapter deals with collisions in fully ionised plasmas. The choice of contents of a textbook is always something of a matter of personal choice. It is easy to complain about what has been left out, and everyone has their own favourite topics. With that caveat, I would question

  7. Systematic evaluation of matrix effect and cross-talk-free method for simultaneous determination of zolmitriptan and N-desmethyl zolmitriptan in human plasma: a sensitive LC-MS/MS method validation and its application to a clinical pharmacokinetic study.

    PubMed

    Patel, Bhargav; Suhagia, B N; Jangid, Arvind G; Mistri, Hiren N; Desai, Nirmal

    2016-03-01

    The objective of the present work was to carry out systematic evaluation to eliminate matrix effect owing to plasma phospholipids as observed during sample preparation and to develop a cross-talk-free sensitive, selective and rapid bioanalytical method for the simultaneous determination of zolmitriptan (ZT) and N-desmethyl zolmitriptan (DZT) in human plasma by liquid chromatography-tandem mass spectrometry using naratriptan as internal standard (IS). The analytes and IS were quantitatively extracted from 200 μL human plasma by solid phase extraction. No cross-talk was found between ZT and DZT having identical product ions. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring and positive ion mode. The total chromatographic run time was 2.5 min. The method was fully validated for sensitivity, selectivity, specificity, linearity, accuracy, precision, recovery, matrix effect, dilution integrity and stability studies. The method was validated over a dynamic concentration range of 0.1-15 ng/mL for ZT and DZT. The method was successfully applied to a bioequivalence study of 2.5 mg ZT tablet formulation in 18 healthy Indian male subjects under fasting conditions. Assay reproducibility was assessed by reanalysis of 62 incurred samples. PMID:26189757

  8. Simultaneous determination of ten alkaloids of crude and wine-processed Rhizoma Coptidis aqueous extracts in rat plasma by UHPLC-ESI-MS/MS and its application to a comparative pharmacokinetic study.

    PubMed

    Qian, Xiao-Cui; Zhang, Liang; Tao, Yi; Huang, Ping; Li, Jun-Song; Chai, Chuan; Li, Wen; Di, Liu-Qing; Cai, Bao-Chang

    2015-02-01

    Rhizoma coptidis (R.C.), a widely used traditional Chinese medicine, has been used for centuries in the treatment of hypertension, inflammation, dysentery and liver diseases, etc. Wine-processing is a specialized technology by sautéing crude herbal medicine using Chinese rice wine. This paper was designed to establish a simultaneous quantitative method of ten alkaloids (berberine, coptisine, palmatine, jatrorrhizine, epiberberine, magnoflorine, columbamine, noroxyhydrastinine, oxyberberine and 8-oxocoptisine) in rat plasma. Furthermore, the pharmacokinetics of those alkaloids after administration of crude and wine-processed R.C. aqueous extracts was compared. As a result, a ultra high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) method was developed and validated for the first time. Chromatographic separation was achieved on a C18 column using gradient elution with the mobile phase consisting of acetonitrile and water (containing 0.2% formic acid) at a flow rate of 0.2 ml/min. The validated method showed good linearity over a wide concentration range (r>0.99), and lower limits of quantification less than 5.46 ng/ml for the each analyte. The intra- and inter-day assay variability was below 9.9% and 10.5% for all analytes, respectively. The extraction recovery of those alkaloids and I.S. ranged from 65.3% to 90.7%. The validated method has been successfully applied to pharmacokinetic comparison after administration of crude and wine-processed R.C. aqueous extracts. Pharmacokinetic comparative study showed that Cmax of coptisine and 8-oxocoptisine and AUC0-t of coptisine, palmatine and 8-oxocoptisine were increased significantly (p<0.05) after wine-processing, while other compounds didn't show significant difference, which suggested that wine-processing exerted limited effects on the absorption of alkaloids. These results might be helpful for R.C.' clinical reasonable application and further studies on its wine

  9. A HPLC-MS/MS method for the quantitation of free, conjugated, and total HDND-7, a novel hesperetin derivative, in rat plasma and tissues: Application to the pharmacokinetic and tissue distribution study.

    PubMed

    Shen, Chenlin; Chen, Ruonan; Qian, Zhengyue; Huang, Cheng; Meng, Xiaoming; Ma, Taotao; Chen, Zhaolin; Huang, Xiaohui; Li, Lan; Zang, Hongmei; Li, Jun

    2016-01-25

    A sensitive and reliable HPLC-MS/MS method was developed and validated for the determination of free (unconjugated), glucuronidated, sulfated, and total (free and conjugated) HDND-7 in rat plasma and tissues. Plasma and tissues samples were treated prior to and after the enzyme hydrolysis. Chromatographic separation was achieved on a Phenomenex Luna C18 column (150 × 4.6mm, 3 μm), using isocratic mobile phase consisting of 0.1% formic acid-acetonitrile (50:50, v/v) at a flow rate of 300 μl/min. The detection was performed on a triple quadruple tandem mass spectrometer using positive electrospray ionization (ESI) source with a chromatographic run time of 5.0 min. The detection was operated by multiple reaction monitoring (MRM) of the transitions of m/z 429.3 → 223.9 for HDND-7 and 272.9 → 152.9 for naringenin (IS), respectively. This method was validated in terms of specificity, linearity, precision, accuracy, and stability. The calibration curves for plasma and tissues were linear over a wide concentration range of 0.02-40 μg/ml with a lower limit of quantification (LLOQ) of 0.02 μg/ml. Mean extraction recoveries in plasma and tissues ranged from 87.4 to 97.1% and from 54.2 to 70.5%, respectively. The intra- and inter-day precision values were below 15% and the accuracy was within ± 15%. The samples were stable under all the tested conditions. This method has been successfully applied to the pharmacokinetic study following oral doses of 25, 50 and 100mg/kg and intravenous dose of 25mg/kg, and tissue distribution study following oral dose of 50mg/kg.

  10. High-throughput determination of faropenem in human plasma and urine by on-line solid-phase extraction coupled to high-performance liquid chromatography with UV detection and its application to the pharmacokinetic study.

    PubMed

    Xie, Rui; Wen, Jun; Wei, Hua; Fan, Guorong; Zhang, Dabing

    2010-05-01

    An automated system using on-line solid-phase extraction and HPLC with UV detection was developed for the determination of faropenem in human plasma and urine. Analytical process was performed isocratically with two reversed-phase columns connected by a switching valve. After simple pretreatment for plasma and urine with acetonitrile, a volume of 100microl upper layer of the plasma or urine samples was injected for on-line SPE column switching HPLC-UV analysis. The analytes were retained on the self-made trap column (Lichrospher C(18), 4.6mmx37mm, 25microm) with the loading solvent (20mM NaH(2)PO(4) adjusted pH 3.5) at flow rate of 2mlmin(-1), and most matrix materials were removed from the column to waste. After 0.5min washing, the valve was switched to another position so that the target analytes could be eluted from trap column to analytical column in the back-flush mode by the mobile phase (acetonitrile-20mM NaH(2)PO(4) adjusted pH 3.5, 16:84, v/v) at flow rate of 1.5mlmin(-1), and then separated on the analytical column (Ultimate XB-C(18), 4.6mmx50mm, 5microm).The complete cycle of the on-line SPE preconcentration purification and HPLC separation of the analytes was 5min. Calibration curves with good linearities (r=0.9994 for plasma sample and r=0.9988 for urine sample) were obtained in the range 0.02-5microgml(-1) in plasma and 0.05-10microg ml(-1) in urine for faropenem. The optimized method showed good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. The method was successfully utilized to quantify faropenem in human plasma and urine to support the clinical pharmacokinetic studies. PMID:20036477

  11. Mechanistic Study of Plasma Damage of Low k Dielectric Surfaces

    SciTech Connect

    Bao Junjing; Shi Hualiang; Huang Huai; Ho, P. S.; Liu Junjun; Goodner, M. D.; Moinpour, M.; Kloster, G. M.

    2007-10-31

    Plasma damage to low k dielectric materials was investigated from a mechanistic point of view. Low k dielectric films were treated by plasma Ar, O{sub 2}, N{sub 2}/H{sub 2}, N{sub 2} and H{sub 2} in a standard RIE chamber and the damage was characterized by Angle Resolved X-ray Photoelectron Spectroscopy (ARXPS), X-Ray Reflectivity (XRR), Fourier Transform Infrared Spectroscopy (FTIR) and Contact Angle measurements. Both carbon depletion and surface densification were observed on the top surface of damaged low k materials while the bulk remained largely unaffected. Plasma damage was found to be a complicated phenomenon involving both chemical and physical effects, depending on chemical reactivity and the energy and mass of the plasma species. A downstream hybrid plasma source with separate ions and atomic radicals was employed to study their respective roles in the plasma damage process. Ions were found to play a more important role in the plasma damage process. The dielectric constant of low k materials can increase up to 20% due to plasma damage and we attributed this to the removal of the methyl group making the low k surface hydrophilic. Annealing was generally effective in mitigating moisture uptake to restore the k value but the recovery was less complete for higher energy plasmas. Quantum chemistry calculation confirmed that physisorbed water in low k materials induces the largest increase of dipole moments in comparison with changes of surface bonding configurations, and is primarily responsible for the dielectric constant increase.

  12. Elliptical X-ray analyzer spectrograph application to a laser-produced plasma

    NASA Astrophysics Data System (ADS)

    Tanaka, Tina J.; Palmer, Merrill A.; Henke, Burton L.

    1985-08-01

    A preliminary experimental study was conducted on the application of an elliptical analyzer spectrograph to X-ray diagnostics of pulsed plasmas. This spectrograph was designed to record a range of 100-2000 eV X-rays on calibrated Kodak RAR-21497 film. Using point calibrations and theoretical models, the spectrograph efficiency was predicted. Basic spectrograph geometry and photographic calibrations are presented in companion papers. A 20 J, 6 ns duration Nd:glass laser pulse was focussed upon planar targets of gold, aluminum, teflon and boron carbide. Sample spectra for line and X-ray yields analysis are presented.

  13. Raman spectroscopic study of plasma-treated salmon DNA

    SciTech Connect

    Lee, Geon Joon; Kim, Yong Hee; Choi, Eun Ha; Kwon, Young-Wan

    2013-01-14

    In this research, we studied the effect of plasma treatment on the optical/structural properties of the deoxyribonucleic acid (DNA) extracted from salmon sperm. DNA-cetyltrimethylammonium (CTMA) films were obtained by complexation of DNA with CTMA. Circular dichroism (CD) and Raman spectra indicated that DNA retained its double helical structure in the solid film. The Raman spectra exhibited several vibration modes corresponding to the nuclear bases and the deoxyribose-phosphate backbones of the DNA, as well as the alkylchains of CTMA. Dielectric-barrier-discharge (DBD) plasma treatment induced structural modification and damage to the DNA, as observed by changes in the ultraviolet-visible absorption, CD, and Raman spectra. The optical emission spectra of the DBD plasma confirmed that DNA modification was induced by plasma ions such as reactive oxygen species and reactive nitrogen species.

  14. Determination of hydromorphone in human plasma by a sensitive RP-HPLC-ESI-MS method and its application to a clinical pharmacokinetic study in postoperative patients after low dose intravenous administration with infusion pump.

    PubMed

    Sun, Luning; Pan, Yinbin; Ding, Li; Luo, Xuemei; Yan, Zhengyu; Liu, Cunming; Qian, Yanning; Chu, Yan

    2012-03-01

    A sensitive reverse phase high performance liquid chromatography-electrospray ionization-mass spectrometry (RP-HPLC-ESI-MS) method has been developed and validated for the determination of hydromorphone in human plasma using naloxone as the internal standard (IS). After alkalization with saturated sodium bicarbonate, the plasma samples were extracted with ethyl acetate. Chromatographic separation was performed on a C18 column with the column temperature of 50 °C and a mobile phase of 5mM ammonium acetate buffer containing 1% formic acid-methanol (88:12, v/v). Hydromorphone and the IS were detected by selected ion monitoring using the protonated molecules at m/z 286.2 for hydromorphone and m/z 328.2 for the IS. Calibration curve was linear over the range of 0.01-50 ng/mL. The lower limit of quantification was 0.01 ng/mL. The method was successfully applied to the pharmacokinetic study in postoperative patients after intravenous infusion of 1.5mg hydromorphone hydrochloride. The obtained main pharmacokinetic parameters of hydromorphone in postoperative patients were as follows: the maximum hydromorphone plasma concentration (C(max)) was (24.15 ± 12.51)ng/mL, the time to the C(max) was (10.0 ± 0.0)min, and the elimination half-life was (2.7 ± 0.8)h. PMID:22169470

  15. An LC-MS/MS method for the simultaneous determination of lycorine and galanthamine in rat plasma and its application to pharmacokinetic study of Lycoris radiata extract in rats.

    PubMed

    Zhou, Xin; Liu, Yue-bin; Huang, Shan; Liu, Ying

    2014-12-01

    A rapid, sensitive, and selective liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of lycorine and galanthamine, two major constituents in Lycoris radiata extract, in rat plasma. Liquid-liquid extraction with ethyl ether was carried out using diphenhydramine as the internal standard. The two bioactive alkaloids were separated on a Zorbax SB-C18 reserved-phase column (150 mm × 4.6 mm, i.d., 5 μm) by gradient elution using a mobile phase consisting of methanol with 0.1% formic acid (A) and water with 0.1% formic acid (B) at a flow rate of 0.6 mL/min. All analytes showed good linearity over a wide concentration range (r (2)>0.99) and the lower limit of quantification was 3.00 ng/mL for each analyte. The average extraction recovery of the analytes from rat plasma was more than 82.15%, and the intra-day and inter-day accuracy and precision of the assay were less than 12.6%. The validated method was successfully applied to monitoring the concentrations and pharmacokinetic studies of two Amaryllidaceous alkaloids in rat plasma after an oral administration of Lycoris radiata extract.

  16. Ultra-fast LC-ESI-MS/MS method for the simultaneous determination of six highly toxic Aconitum alkaloids from Aconiti kusnezoffii radix in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Liu, Jingjing; Li, Qing; Yin, Yidi; Liu, Ran; Xu, Huarong; Bi, Kaishun

    2014-01-01

    A fast, sensitive, and efficient ultra-fast LC-ESI-MS/MS method was developed for the simultaneous quantitation of six highly toxic Aconitum alkaloids, that is, aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, in rat plasma after oral administration of crude ethanol extracts from Aconiti kusnezoffii radix by ultrasonic extraction, reflux extraction for 1 h, and reflux extraction for 3 h, respectively. The separation of six Aconitum alkaloids and aminopyrine (internal standard) was performed on an InertSustain® C18 column, and the quantification of the analytes was performed on a 4000Q ultra-fast LC-MS/MS system with turbo ion spray source in the positive ion and multiple-reaction monitoring mode. Absolute recoveries ranged within 65.06-85.1% for plasma samples. The intra- and interday precision and accuracy of analytes were satisfactory. The methods were validated with sensitivity reaching the lower LOQ for aconitine, mesaconitine, hypaconitine, benzoylaconine, benzoylmesaconine, and benzoylhypaconine, which were 0.025, 0.025, 0.050, 0.025, 0.025, and 0.100 ng/mL, respectively. The method was successfully applied to a pharmacokinetic study of six Aconitum alkaloids in rat plasma after oral administration of crude ethanol extracts from the raw root of Aconitum kusnezoffii Reichb. by three different extraction processes.

  17. Development and validation of an LC-MS/MS method for simultaneous quantification of levodopa and MD01 in rat plasma and its application to a pharmacokinetic study of mucuna pruriens extract.

    PubMed

    Yang, Guangjie; Zhang, Fangrong; Deng, Linfang; Chen, Chang; Cheng, Zhongzhe; Huang, Jiangeng; Liu, Jiangyun; Jiang, Hongliang

    2016-09-01

    Mucuna pruriens, an ancient Indian herbal medicine containing levodopa, is widely used for Parkinson's disease. In order to simultaneously determine levodopa and 1,1-dimethyl-3-carboxy-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (MD01) in rat plasma, an improved LC-MS/MS method was developed and validated for a pharmacokinetic study in rats orally administered levodopa or Mucuna pruriens extract (MPE). Elimination of matrix effect and improvement of extraction recovery were achieved through systematic optimization of reversed-phase and hydrophilic interaction chromatographic conditions together with sample clean-up procedures. A satisfactory chromatographic performance was obtained with a Thermo Aquasil C18 column (50 × 2.1 mm, 3 µm) using acetonitrile and water containing 0.2% formic acid as mobile phases. Futhermore, sodium metabisulfite and formic acid were used as stabilizers in neat solutions as well as rat plasma. The method was validated in a dynamic range of 20.0-10,000 ng/mL for levodopa and MD01; the intra- and inter-day precision and accuracy were acceptable. The method was successfully utilized to determine the levodopa level in plasma samples of rats administered levodopa or MPE. Pharmacokinetic results showed that an increase in the AUC of levodopa was observed in rats following oral administration of multiple doses of MPE. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26928470

  18. An LC-MS/MS method for the simultaneous determination of lycorine and galanthamine in rat plasma and its application to pharmacokinetic study of Lycoris radiata extract in rats.

    PubMed

    Zhou, Xin; Liu, Yue-bin; Huang, Shan; Liu, Ying

    2014-12-01

    A rapid, sensitive, and selective liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of lycorine and galanthamine, two major constituents in Lycoris radiata extract, in rat plasma. Liquid-liquid extraction with ethyl ether was carried out using diphenhydramine as the internal standard. The two bioactive alkaloids were separated on a Zorbax SB-C18 reserved-phase column (150 mm × 4.6 mm, i.d., 5 μm) by gradient elution using a mobile phase consisting of methanol with 0.1% formic acid (A) and water with 0.1% formic acid (B) at a flow rate of 0.6 mL/min. All analytes showed good linearity over a wide concentration range (r (2)>0.99) and the lower limit of quantification was 3.00 ng/mL for each analyte. The average extraction recovery of the analytes from rat plasma was more than 82.15%, and the intra-day and inter-day accuracy and precision of the assay were less than 12.6%. The validated method was successfully applied to monitoring the concentrations and pharmacokinetic studies of two Amaryllidaceous alkaloids in rat plasma after an oral administration of Lycoris radiata extract. PMID:25480582

  19. Development of a UFLC-MS/MS method for the simultaneous determination of seven tea catechins in rat plasma and its application to a pharmacokinetic study after administration of green tea extract.

    PubMed

    Huo, Yanshuang; Zhang, Qian; Li, Qing; Geng, Bingjie; Bi, Kaishun

    2016-06-01

    A rapid, sensitive and selective ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed and validated for simultaneous determination of seven green tea catechins including catechin (C), (-)-epicatechin (EC), gallocatechin (GC), (-)-epigallocatechin (EGC), (-)-epicatechin-3-gallate (ECG), gallocatechin-3-gallate (GCG) and (-)-epigallocatechin-3-gallate (EGCG) in rat plasma. The plasma samples were firstly hydrolysed with the mixture of β-glucuronidase and sulfatase, which were then extracted by liquid-liquid extraction with ethyl acetate-isopropanol (1:1, v/v). The analytes were separated on a Venusil MP C18 column (Venusil, China) with a gradient elution at a flow rate of 0.4mL/min. The detection was performed in negative ionization and multiple reaction monitoring (MRM) mode. All the calibration curves exhibited good linearity (r>0.9943) with intra- and inter-day precisions of less than 14.3% and the accuracy deviations ranging from -8.8% to 7.5%. The extraction recoveries of the analytes and ethyl gallate (internal standard) were all more than 72%. The validated method was successfully applied to a pharmacokinetic study of seven catechins in rat plasma after oral administration of the green tea extract at different doses of 0.4, 1.2 and 2.0g/kg. PMID:27037979

  20. Determination of newly synthesized lipoic acid-niacin dimer in rat plasma by UPLC/electrospray ionization tandem mass spectrometry: assay development, validation and application to a pharmacokinetic study.

    PubMed

    Chen, Xiao; Gao, Jingwen; Jiang, Yiming; Huang, Ping; Xie, Yuhui; Pi, Rongbiao; Zhu, Shuzhen; Yao, Meicun

    2014-02-01

    A simple, sensitive and specific ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method was developed to determine the newly synthesized compound lipoic acid-niacin dimer (N2L) in plasma. Plasma samples were precipitated by methanol using tetrahydropalmatine as internal standard. Chromatographic separation was achieved on an Acquity BEH C18 (2.1 × 50 mm i.d., 1.7 µm) column; the mobile phase contains methanol and buffer solution (water with 0.5% formic acid and 10 mmol/L ammonium acetate). Multiple reaction monitoring (m/z 353.9 → 148.6 for N2L and m/z 356.0 → 192.0 for internal standard) was performed for detection and quantification. The method was validated to be rapid, specific, accurate and precise over the concentration range of 1-750 ng/mL; N2L was not stable on the bench-top or during freeze-freeze-thaw cycles in plasma, but was stable in the stock solution and after preparation in the autosampler for 24 h. The utility of the assay was confirmed by pharmacokinetic study of N2L in rats.

  1. Application of an LC-MS/MS method for reliable determination of amodiaquine, N-desethylamodiaquine, artesunate and dihydroartemisinin in human plasma for a bioequivalence study in healthy Indian subjects.

    PubMed

    Rathod, Dhiraj M; Patel, Keyur R; Mistri, Hiren N; Jangid, Arvind G; Shrivastav, Pranav S; Sanyal, Mallika

    2016-05-30

    A sensitive and high throughput bioanalytical method has been developed for reliable determination of amodiaquine (AQ), N-desethylamodiaquine (DEAQ), artesunate (AS) and dihydroartemisinin (DHA) in human plasma by LC-MS/MS. The method employs a solid phase extraction procedure without an evaporation step and with optimum use of organic solvents to circumvent degradation of artemisinin derivatives. The analytes and their deuterated internal standards (ISs) were analyzed on Hypersil Gold (100 mm × 4.6mm, 5 μm) column using acetonitrile and 2.0mM ammonium formate (pH 2.50) in 80:20 (v/v) ratio as the mobile phase. A triple quadrupole mass spectrometer equipped with an electrospray ionization interface was used to detect and quantify the analytes. The method was established over the concentration range of 0.250-30.0 ng/mL, 1.50-180 ng/mL, 2.00-600 ng/mL and 5.00-1400 ng/mL for AQ, DEAQ, AS and DHA respectively using 250 μL human plasma. The intra-day and inter-day accuracy and precision (% CV) across quality controls varied from 93.3-105.0% and 1.7-8.3 respectively for all the analytes. The stability was assessed in whole blood as well as in plasma samples under different conditions. All four analytes were stable in whole blood up to 2h on melting ice. The long term stability in plasma was ascertained up to 90 days. IS-normalized matrix factors ranged from 0.988-1.023 for all the analytes. The method was successfully applied to a bioequivalence study using 50mg artesunate and 135 mg amodiaquine fixed dose formulation in 14 healthy subjects.

  2. LC-UV Determination of Baicalin in Rabbit Plasma and Tissues for Application in Pharmacokinetics and Tissue Distribution Studies of Baicalin after Intravenous Administration of Liposomal and Injectable Formulations.

    PubMed

    Wei, Yumeng; Pi, Chao; Yang, Gang; Xiong, Xiaoming; Lan, Yongshu; Yang, Hongru; Zhou, Yang; Ye, Yun; Zou, Yonggen; Zheng, Wenwu; Zhao, Ling

    2016-04-19

    A simple and sensitive LC-UV method to investigate the pharmacokinetics and biodistribution pattern of baicalin in rabbits was established and validated. Baicalin and the internal standard, rutin, were extracted from biosamples using acetonitrile as protein precipitation after pretreated with ammonium acetate buffer (pH 3.5; 1 M) to obtain a pure chromatographic peak and high extraction recovery. Chromatographic separation was achieved on a reverse-phase C18 column with a gradient elution at flow rate of 1.0 mL/min. UV absorption was set at 278 nm. Chromatographic response was linear over the ranges of 0.05-10.00 μg/mL in plasma and 0.05-300.00 μg/g in tissues with the limits of quantification of 50.0 ng/mL in plasma and tissues, and the limit of detection of baicalin in bio-samples of 15 ng/mL. The RSD of intra-and inter-day for the biosamples were from 4.19% to 10.84% and from 4.37% to 10.93%, respectively. The accuracy of plasma and tissue samples ranged from 81.6% to 95.2% and 80.8% to 98.4%, respectively. The extraction recoveries ranged from 81.5% to 88.3% for plasma, from 73.1% to 93.2% for tissues, respectively. Baicalin was stable in rabbit biosamples. The validated method was successfully applied to the study of the pharmacokinetics and tissue distribution of baicalin after intravenous administration of liposomal and injectable formulations to rabbits. Compared to baicalin injection, the pharmacokinetics and biodistribution behavior of baicalin was altered significantly in rabbits treated with its liposomes and drug concentration in the lungs was greatly increased.

  3. A micro-scale plasma spectrometer for space and plasma edge applications (invited)

    NASA Astrophysics Data System (ADS)

    Scime, E. E.; Keesee, A. M.; Dugas, M.; Ellison, S.; Tersteeg, J.; Wagner, G.; Barrie, A.; Rager, A.; Elliott, D.

    2016-11-01

    A plasma spectrometer design based on advances in lithography and microchip stacking technologies is described. A series of curved plate energy analyzers, with an integrated collimator, is etched into a silicon wafer. Tests of spectrometer elements, the energy analyzer and collimator, were performed with a 5 keV electron beam. The measured collimator transmission and energy selectivity were in good agreement with design targets. A single wafer element could be used as a plasma processing or fusion first wall diagnostic.

  4. High temperature UF6 RF plasma experiments applicable to uranium plasma core reactors

    NASA Technical Reports Server (NTRS)

    Roman, W. C.

    1979-01-01

    An investigation was conducted using a 1.2 MW RF induction heater facility to aid in developing the technology necessary for designing a self critical fissioning uranium plasma core reactor. Pure, high temperature uranium hexafluoride (UF6) was injected into an argon fluid mechanically confined, steady state, RF heated plasma while employing different exhaust systems and diagnostic techniques to simulate and investigate some potential characteristics of uranium plasma core nuclear reactors. The development of techniques and equipment for fluid mechanical confinement of RF heated uranium plasmas with a high density of uranium vapor within the plasma, while simultaneously minimizing deposition of uranium and uranium compounds on the test chamber peripheral wall, endwall surfaces, and primary exhaust ducts, is discussed. The material tests and handling techniques suitable for use with high temperature, high pressure, gaseous UF6 are described and the development of complementary diagnostic instrumentation and measurement techniques to characterize the uranium plasma, effluent exhaust gases, and residue deposited on the test chamber and exhaust system components is reported.

  5. Hollow cathode plasma coupling study, 1986

    NASA Technical Reports Server (NTRS)

    Wilbur, Paul J.

    1986-01-01

    The electron collection and emission characteristics of a simple hollow cathode contactor, an extended anode hollow cathode contactor supplied by JSC, and a ring cusp magnetic field contactor are presented and the effects of discharge power and argon or xenon expellant flowrate on these characteristics are examined. All of the contactors are shown to exhibit good electron emission performance over a wide range of discharge power and expellant type and flowrate. Good electron performance is shown to be more difficult to achieve. Results suggest that the extended anode and ring cusp contactors should perform satisfactorily to electron emission currents beyond 1000 mA and electron collection currents beyond 500 mA. All contactors performed better on xenon than argon. A general theory of plasma contactor operation in both the electron collection and electron emission modes, which describes the current-limiting effects of space-charge phenomena is given. This current-limiting and collecting phenomenon is shown to be a function of driving potential differences and emitting and collecting surface radius ratio for the case of a spherical geometry. Discharge power did not appear to influence the electron collection current substantially in the experiments so it is suggested in light of the model that the contactors are generally not limited by their ion production capabilities under conditions at which they were tested.

  6. Theoretical and experimental studies of reentry plasmas

    NASA Technical Reports Server (NTRS)

    Dunn, M. G.; Kang, S.

    1973-01-01

    A viscous shock-layer analysis was developed and used to calculate nonequilibrium-flow species distributions in the plasma layer of the RAM vehicle. The theoretical electron-density results obtained are in good agreement with those measured in flight. A circular-aperture flush-mounted antenna was used to obtain a comparison between theoretical and experimental antenna admittance in the presence of ionized boundary layers of low collision frequency. The electron-temperature and electron-density distributions in the boundary layer were independently measured. The antenna admittance was measured using a four-probe microwave reflectometer and these measured values were found to be in good agreement with those predicted. Measurements were also performed with another type of circular-aperture antenna and good agreement was obtained between the calculations and the experimental results. A theoretical analysis has been completed which permits calculation of the nonequilibrium, viscous shock-layer flow field for a sphere-cone body. Results are presented for two different bodies at several different altitudes illustrating the influences of bluntness and chemical nonequilibrium on several gas dynamic parameters of interest. Plane-wave transmission coefficients were calculated for an approximate space-shuttle body using a typical trajectory.

  7. Confinement Studies of Auxiliary Heated NSTX Plasmas

    SciTech Connect

    B.P. LeBlanc; M.G. Bell; R.E. Bell; M.L. Bitter; C. Bourdelle; D.A. Gates; S.M. Kaye; R. Maingi; J.E. Menard; D. Mueller; S.F. Paul; A.L. Roquemore; A. Rosenberg1; S.A. Sabbagh; D. Stutman; E.J. Synakowski; V.A. Soukhanovskii; J.R.Wilson; the NSTX Research Team

    2003-05-06

    The confinement of auxiliary heated NSTX discharges is discussed. The energy confinement time in plasmas with either L-mode or H-mode edges is enhanced over the values given by the ITER97L and ITER98Pby(2) scalings, being up to 2-3 times L-mode and 1.5 times H-mode. TRANSP calculations based on the kinetic profile measurements reproduce the magnetics-based determination of stored energy and the measured neutron production rate. Power balance calculations reveal that, in a high power neutral beam heated H-mode discharge, the ion thermal transport is near neoclassical levels, and well below the electron thermal transport, which is the main loss channel. Perturbative impurity injection techniques indicate the particle diffusivity to be slightly above the neoclassical level in discharges with L-mode edge. High-harmonic fast-wave (HHFW) bulk electron heating is described and thermal transport is discussed. Thermal ion transport is found to be above neoclassical level, but thermal electron transport remains the main loss mechanism. Evidences of an electron thermal internal transport barrier obtained with HHFW heating are presented. A description of H-mode discharges obtained during HHFW heating is presented.

  8. A simplified strong ion model for acid-base equilibria: application to horse plasma.

    PubMed

    Constable, P D

    1997-07-01

    The Henderson-Hasselbalch equation and Stewart's strong ion model are currently used to describe mammalian acid-base equilibria. Anomalies exist when the Henderson-Hasselbalch equation is applied to plasma, whereas the strong ion model does not provide a practical method for determining the total plasma concentration of nonvolatile weak acids ([Atot]) and the effective dissociation constant for plasma weak acids (Ka). A simplified strong ion model, which was developed from the assumption that plasma ions act as strong ions, volatile buffer ions (HCO-3), or nonvolatile buffer ions, indicates that plasma pH is determined by five independent variables: PCO2, strong ion difference, concentration of individual nonvolatile plasma buffers (albumin, globulin, and phosphate), ionic strength, and temperature. The simplified strong ion model conveys on a fundamental level the mechanism for change in acid-base status, explains many of the anomalies when the Henderson-Hasselbalch equation is applied to plasma, is conceptually and algebraically simpler than Stewart's strong ion model, and provides a practical in vitro method for determining [Atot] and Ka of plasma. Application of the simplified strong ion model to CO2-tonometered horse plasma produced values for [Atot] (15.0 +/- 3.1 meq/l) and Ka (2.22 +/- 0.32 x 10(-7) eq/l) that were significantly different from the values commonly assumed for human plasma ([Atot] = 20.0 meq/l, Ka = 3.0 x 10(-7) eq/l). Moreover, application of the experimentally determined values for [Atot] and Ka to published data for the horse (known PCO2, strong ion difference, and plasma protein concentration) predicted plasma pH more accurately than the values for [Atot] and Ka commonly assumed for human plasma. Species-specific values for [Atot] and Ka should be experimentally determined when the simplified strong ion model (or strong ion model) is used to describe acid-base equilibria.

  9. Effect of intraoperative platelet-rich plasma and fibrin glue application on skin flap survival.

    PubMed

    Findikcioglu, Fulya; Findikcioglu, Kemal; Yavuzer, Reha; Lortlar, Nese; Atabay, Kenan

    2012-09-01

    The experiment was designed to compare the effect of intraoperative platelet-rich plasma (PRP) and fibrin glue application on skin flap survival. In this study, bilateral epigastric flaps were elevated in 24 rats. The right-side flaps were used as the control of the left-side flaps. Platelet-rich plasma, fibrin glue, and thrombin had been applied under the flap sites in groups 1, 2, and 3, respectively. Five days later, all flap pedicles were ligated. Necrotic area measurements, microangiography, and histologic and immunohistochemical evaluations were performed to compare the groups. Platelet-rich plasma reduced necrotic area percentages as compared with other groups. Histologically and microangiographically increased number of arterioles were observed in PRP groups. Thrombin when used alone increased flap necrosis. Vascular endothelial growth factor, platelet-derived growth factor, and transforming growth factor β3 primary antibody staining showed increased neovascularization and reepithelialization in all PRP-applied flaps. This study demonstrated that PRP, when applied intraoperatively under the skin flap, may enhance flap survival. Thrombin used alone was found to be unsuitable in flap surgery.

  10. On the design and characterization of a new cold atmospheric pressure plasma jet and its applications on cancer cells treatment.

    PubMed

    Akhlaghi, Morteza; Rajayi, Hajar; Mashayekh, Amir Shahriar; Khani, Mohammadreza; Hassan, Zuhair Mohammad; Shokri, Babak

    2015-01-01

    In this paper, a new configuration of a cold atmospheric pressure plasma jet has been designed and constructed. Poly-methyl-methacrylate was used as a new dielectric in this configuration which in comparison to other dielectrics is inexpensive, more resistant against break, and also more shapeable. Then, the plasma jet parameters such as plume temperature, rotational and vibrational temperatures, power, electrical behavior (voltage and current profile), electron density, and the produced reactive species were characterized. In order to determine the jet temperature and the amount of reactive species, effects of applied voltage, gas flow rate, and distance from the nozzle were studied. The power of the jet was specified using Lissajous curve approach. The plume temperature of the plasma jet was about the room temperature. Optical emission spectroscopy determined the type of reactive species, and also electron density and its corresponding plasma frequency (~6.4 × 10(13) cm(-3) and 4.52 × 10(11) Hz). Because of producing different reactive species, the device can be used in different applications, especially in plasma medicine. Thus, 4T1 cancer cells were treated using this plasma jet. The results showed that this plasma jet has a great potential to kill one of the most aggressive and resistant cancerous cell lines.

  11. On the design and characterization of a new cold atmospheric pressure plasma jet and its applications on cancer cells treatment.

    PubMed

    Akhlaghi, Morteza; Rajayi, Hajar; Mashayekh, Amir Shahriar; Khani, Mohammadreza; Hassan, Zuhair Mohammad; Shokri, Babak

    2015-01-01

    In this paper, a new configuration of a cold atmospheric pressure plasma jet has been designed and constructed. Poly-methyl-methacrylate was used as a new dielectric in this configuration which in comparison to other dielectrics is inexpensive, more resistant against break, and also more shapeable. Then, the plasma jet parameters such as plume temperature, rotational and vibrational temperatures, power, electrical behavior (voltage and current profile), electron density, and the produced reactive species were characterized. In order to determine the jet temperature and the amount of reactive species, effects of applied voltage, gas flow rate, and distance from the nozzle were studied. The power of the jet was specified using Lissajous curve approach. The plume temperature of the plasma jet was about the room temperature. Optical emission spectroscopy determined the type of reactive species, and also electron density and its corresponding plasma frequency (~6.4 × 10(13) cm(-3) and 4.52 × 10(11) Hz). Because of producing different reactive species, the device can be used in different applications, especially in plasma medicine. Thus, 4T1 cancer cells were treated using this plasma jet. The results showed that this plasma jet has a great potential to kill one of the most aggressive and resistant cancerous cell lines. PMID:25908593

  12. Superhydrophilic poly(L-lactic acid) electrospun membranes for biomedical applications obtained by argon and oxygen plasma treatment

    NASA Astrophysics Data System (ADS)

    Correia, D. M.; Ribeiro, C.; Botelho, G.; Borges, J.; Lopes, C.; Vaz, F.; Carabineiro, S. A. C.; Machado, A. V.; Lanceros-Méndez, S.

    2016-05-01

    Poly(L-lactic acid), PLLA, electrospun membranes and films were plasma treated at different times and power with argon (Ar) and oxygen (O2), independently, in order to modify the hydrophobic nature of the PLLA membranes. Both Ar and O2 plasma treatments promote an increase in fiber average size of the electrospun membranes from 830 ± 282 nm to 866 ± 361 and 1179 ± 397 nm, respectively, for the maximum exposure time (970 s) and power (100 W). No influence of plasma treatment was detected in the physical-chemical characteristics of PLLA, such as chemical structure, polymer phase or degree of crystallinity. On the other hand, an increase in the roughness of the films was obtained both with argon and oxygen plasma treatments. Surface wettability studies revealed a decrease in the contact angle with increasing plasma treatment time for a given power and with increasing power for a given time in membranes and films and superhydrophilic electrospun fiber membranes were obtained. Results showed that the argon and oxygen plasma treatments can be used to tailor hydrophilicity of PLLA membranes for biomedical applications. MTT assay results indicated that plasma treatments under Ar and O2 do not influence the metabolic activity of MC3T3-E1 pre-osteoblast cells.

  13. Surface modification of poly(dimethylsiloxane) through oxygen and nitrogen plasma treatment to improve its characteristics towards biomedical applications

    NASA Astrophysics Data System (ADS)

    Gomathi, N.; Mishra, I.; Varma, S.; Neogi, S.

    2015-09-01

    Polymeric materials successfully applied in biomedical applications have an issue of poor surface properties which may restrict their applications as biomaterials. The present paper aims to study the effect of oxygen and nitrogen plasma treatment on physico-chemical properties of poly(dimethylsiloxane) (PDMS) and enhancement in its biocompatibility. Various characterization techniques including Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy (SEM), atomic force microscopy were used to evaluate the changes in surface chemistry and morphology of plasma treated PDMS. Changes in the wettability after plasma treatments and the effects of ageing on wettability were studied by contact angle measurement. Ageing studies showed that the contact angle was stable after two hours. The effect of plasma treatment on biocompatibility was studied through cell adhesion and MTT using 3T3 fibroblast cells. Morphology of cells obtained through SEM was analyzed using ImageJ software. Among the different treated and untreated samples, substantial enhancement in biocompatibility was observed for nitrogen plasma treated PDMS for 5 min in terms of highest cell area observed from cell adhesion test and highest cell viability observed from MTT test. This may be probably due to its highest polarity (0.4) and surface energy (33.3 N mm-2) with a moderate surface roughness (Rrms = 100.24 nm) among the other treated and untreated samples.

  14. Plasma application for detoxification of Jatropha phorbol esters

    NASA Astrophysics Data System (ADS)

    Kongmany, S.; Matsuura, H.; Furuta, M.; Okuda, S.; Imamura, K.; Maeda, Y.

    2013-06-01

    Atmospheric pressure non-thermal dielectric barrier discharge (DBD) plasma generated by helium gas at high voltage and input power of about 50 W was first applied to detoxification of Jatropha curcas phorbol esters (J. PEs) as well as standard phorbol ester (4β-12-O-tetradecanoyl phorbol-13-acetate, TPA) in water and methanol. Plasma irradiation on the solution sample was conducted for 15 min. In aqueous solution, only 16% of TPA was degraded and complete degradation of J. PEs was observed. On the contrary, complete degradation of both TPA and J. PEs in methanol was achieved by the same plasma irradiation condition. Hydroxyl radical (•OH) generated by plasma irradiation of the solution is expected as the main radical inducing the degradation of PEs.

  15. Gas plasma sterilization--application of space-age technology.

    PubMed

    Crow, S; Smith, J H

    1995-08-01

    Gas plasma sterilization is new to the healthcare field. The first such sterilizer has been manufactured by Advanced Sterilization Products (J&J, Irvine, CA). The system uses hydrogen peroxide as the substrate gas and radio frequency emissions to generate plasma. This system is a low-temperature, quick-acting process with no toxic residues. It appears that this sterilizer system holds promise in the healthcare field and could help to reduce the use of ethylene oxide.

  16. Gas plasma sterilization--application of space-age technology.

    PubMed

    Crow, S; Smith, J H

    1995-08-01

    Gas plasma sterilization is new to the healthcare field. The first such sterilizer has been manufactured by Advanced Sterilization Products (J&J, Irvine, CA). The system uses hydrogen peroxide as the substrate gas and radio frequency emissions to generate plasma. This system is a low-temperature, quick-acting process with no toxic residues. It appears that this sterilizer system holds promise in the healthcare field and could help to reduce the use of ethylene oxide. PMID:7594394

  17. Development of a plasma sprayed ceramic gas path seal for high pressure turbine applications

    NASA Technical Reports Server (NTRS)

    Shiembob, L. T.

    1977-01-01

    The plasma sprayed graded layered yittria stabilized zirconia (ZrO2)/metal(CoCrAlY) seal system for gas turbine blade tip applications up to 1589 K (2400 F) seal temperatures was studied. Abradability, erosion, and thermal fatigue characteristics of the graded layered system were evaluated by rig tests. Satisfactory abradability and erosion resistance was demonstrated. Encouraging thermal fatigue tolerance was shown. Initial properties for the plasma sprayed materials in the graded, layered seal system was obtained, and thermal stress analyses were performed. Sprayed residual stresses were determined. Thermal stability of the sprayed layer materials was evaluated at estimated maximum operating temperatures in each layer. Anisotropic behavior in the layer thickness direction was demonstrated by all layers. Residual stresses and thermal stability effects were not included in the analyses. Analytical results correlated reasonably well with results of the thermal fatigue tests. Analytical application of the seal system to a typical gas turbine engine application predicted performance similar to rig specimen thermal fatigue performance. A model for predicting crack propagation in the sprayed ZrO2/CoCrAlY seal system was proposed, and recommendations for improving thermal fatigue resistance were made. Seal system layer thicknesses were analytically optimized to minimize thermal stresses in the abradability specimen during thermal fatigue testing. Rig tests on the optimized seal configuration demonstrated some improvement in thermal fatigue characteristics.

  18. Skin and plasma autofluorescence during hemodialysis: a pilot study.

    PubMed

    Graaff, Reindert; Arsov, Stefan; Ramsauer, Bernd; Koetsier, Marten; Sundvall, Nils; Engels, Gerwin E; Sikole, Aleksandar; Lundberg, Lennart; Rakhorst, Gerhard; Stegmayr, Bernd

    2014-06-01

    Skin autofluorescence (AF) is related to the accumulation of advanced glycation end products (AGEs) and is one of the strongest prognostic markers of mortality in hemodialysis (HD) patients. The aim of this pilot study was to investigate whether changes in skin AF appear after a single HD session and if they might be related to changes in plasma AF. Skin and plasma AF were measured before and after HD in 35 patients on maintenance HD therapy (nine women and 26 men, median age 68 years, range 33-83). Median dialysis time was 4 h (range 3-5.5). Skin AF was measured noninvasively with an AGE Reader, and plasma AF was measured before and after HD at 460 nm after excitation at 370 nm. The HD patients had on average a 65% higher skin AF value than age-matched healthy persons (P < 0.001). Plasma AF was reduced by 14% (P < 0.001), whereas skin AF was not changed after a single HD treatment. No significant influence of the reduced plasma AF on skin AF levels was found. This suggests that the measurement of skin AF can be performed during the whole dialysis period and is not directly influenced by the changes in plasma AF during HD.

  19. Skin and plasma autofluorescence during hemodialysis: a pilot study.

    PubMed

    Graaff, Reindert; Arsov, Stefan; Ramsauer, Bernd; Koetsier, Marten; Sundvall, Nils; Engels, Gerwin E; Sikole, Aleksandar; Lundberg, Lennart; Rakhorst, Gerhard; Stegmayr, Bernd

    2014-06-01

    Skin autofluorescence (AF) is related to the accumulation of advanced glycation end products (AGEs) and is one of the strongest prognostic markers of mortality in hemodialysis (HD) patients. The aim of this pilot study was to investigate whether changes in skin AF appear after a single HD session and if they might be related to changes in plasma AF. Skin and plasma AF were measured before and after HD in 35 patients on maintenance HD therapy (nine women and 26 men, median age 68 years, range 33-83). Median dialysis time was 4 h (range 3-5.5). Skin AF was measured noninvasively with an AGE Reader, and plasma AF was measured before and after HD at 460 nm after excitation at 370 nm. The HD patients had on average a 65% higher skin AF value than age-matched healthy persons (P < 0.001). Plasma AF was reduced by 14% (P < 0.001), whereas skin AF was not changed after a single HD treatment. No significant influence of the reduced plasma AF on skin AF levels was found. This suggests that the measurement of skin AF can be performed during the whole dialysis period and is not directly influenced by the changes in plasma AF during HD. PMID:24164288

  20. Study of channel formation and relativistic ultra-short laser pulse propagation in helium plasma

    NASA Astrophysics Data System (ADS)

    Yu, Changhai; Tian, Ye; Li, Wentao; Zhang, Zhijun; Qi, Rong; Wang, Wentao; Wang, Cheng; Liu, Jiansheng

    2016-05-01

    In this study, plasma channel formation in pure He plasma (ionization electron density 0.01-0.1n c ) interacting with ultra-short relativistic laser pulses (50 fs, >1019 W cm-2) was observed and analyzed. By appropriately selecting the laser pulse and gas backing pressure of the gas jet, a clear density channel longer than 300 μm and wider than 25 μm was achieved in less than 1.5 ps following the passage of the laser pulse, with a radial electron density gradient of ~1023 cm-4 at the channel walls. Numerical simulations for studying the affects of the plasma density, kinetic motion of electrons and ions, and nonlinear laser propagation on the plasma channel formation were carried out, which reproduced the experimental features. These density channels were mainly driven by the radial expulsion of plasma ions, with strong continuous laser self-focusing acting to improve the channeling efficiency. These channels can guide the propagation of ultra-intense laser pulses and supply several advanced applications in high-energy physics, including fast-ignition inertial confinement fusion, plasma-based particle accelerations, and sources of radiation.

  1. Study on the effect of target on plasma parameters of magnetron sputtering discharge plasma

    SciTech Connect

    Saikia, P.; Kakati, B.; Saikia, B. K.

    2013-10-15

    In this study, the effect of magnetron target on different plasma parameters of Argon/Hydrogen (Ar - H{sub 2}) direct current (DC) magnetron discharge is examined. Here, Copper (Cu) and Chromium (Cr) are used as magnetron targets. The value of plasma parameters such as electron temperature (kT{sub e}), electron density (N{sub e}), ion density (N{sub i}), degree of ionization of Ar, and degree of dissociation of H{sub 2} for both the target are studied as a function of input power and hydrogen content in the discharge. The plasma parameters are determined by using Langmuir probe and Optical emission spectroscopy. On the basis of the different reactions in the gas phase, the variation of plasma parameters and sputtering rate are explained. The obtained results show that electron and ion density decline with gradual addition of Hydrogen in the discharge and increase with rising input power. It brings significant changes on the degree of ionization of Ar and dissociation of H{sub 2}. The enhanced value of electron density (N{sub e}), ion density (N{sub i}), degree of Ionization of Ar, and degree of dissociation of H{sub 2} for Cr compared to Cu target is explained on the basis of it's higher Ion Induced Secondary Electron Emission Coefficient (ISEE) value.

  2. THz Plasma Diagnostics: an evolution from FIR and Millimeter waves historical applications

    NASA Astrophysics Data System (ADS)

    Bombarda, F.; Doria, A.; Galatola Teka, G.; Giovenale, E.; Zerbini, M.

    2016-08-01

    Extremely broadband (100 GHz-30 THz) single cycle THz pulses are routinely generated with femtosecond laser for Time Domain Spectroscopy applications (TDS). The wide frequency range has an unquestionable diagnostic potential for Tokamak plasmas and not surprisingly THz TDS finds a natural field of application in this area, which is an evolution of the FIR and millimeter waves diagnostics, where ENEA Frascati holds historical expertise. By illuminating the plasma with a THz beam, phase, intensity and polarization of both reflected and transmitted beams can be detected, devising a single diagnostic instrument capable of measuring multiple plasma parameters. We will describe and discuss the laboratory work now in progress to realise a tailored THz-TDS spectrometer with design parameters optimised for the requirements of Tokamak plasmas and the tests of optical fibers and quasioptical couplers to optimise access to plasma. ENEA Frascati and the Photonics group of Physics Dept. of Oxford University are collaborating on this subject [1].

  3. THz Plasma Diagnostics: an evolution from FIR and Millimeter waves historical applications

    NASA Astrophysics Data System (ADS)

    Bombarda, F.; Doria, A.; Galatola Teka, G.; Giovenale, E.; Zerbini, M.

    2016-08-01

    Extremely broadband (100 GHz–30 THz) single cycle THz pulses are routinely generated with femtosecond laser for Time Domain Spectroscopy applications (TDS). The wide frequency range has an unquestionable diagnostic potential for Tokamak plasmas and not surprisingly THz TDS finds a natural field of application in this area, which is an evolution of the FIR and millimeter waves diagnostics, where ENEA Frascati holds historical expertise. By illuminating the plasma with a THz beam, phase, intensity and polarization of both reflected and transmitted beams can be detected, devising a single diagnostic instrument capable of measuring multiple plasma parameters. We will describe and discuss the laboratory work now in progress to realise a tailored THz-TDS spectrometer with design parameters optimised for the requirements of Tokamak plasmas and the tests of optical fibers and quasioptical couplers to optimise access to plasma. ENEA Frascati and the Photonics group of Physics Dept. of Oxford University are collaborating on this subject [1].

  4. Feedback control of plasma instabilities with charged particle beams and study of plasma turbulence

    NASA Technical Reports Server (NTRS)

    Tham, Philip Kin-Wah

    1994-01-01

    . A plasma instability is usually observed in its saturated state and appears as a single feature in the frequency spectrum with a single azimuthal and parallel wavenumbers. The physics of the non-zero spectral width was investigated in detail because the finite spectral width can cause "turbulent" transport. One aspect of the "turbulence" was investigated by obtaining the scaling of the linear growth rate of the instabilities with the fluctuation levels. The linear growth rates were measured with the established gated feedback technique. The research showed that the ExB instability evolves into a quasi-coherent state when the fluctuation level is high. The coherent aspects were studied with a bispectral analysis. Moreover, the single spectral feature was discovered to be actually composed of a few radial harmonics. The radial harmonics play a role in the nonlinear saturation of the instability via three-wave coupling.

  5. Simulation studies of plasma lens experiments at Daresbury laboratory

    NASA Astrophysics Data System (ADS)

    Hanahoe, K.; Mete, O.; Xia, G.; Angal-Kalinin, D.; Jones, J.; Smith, J.

    2016-03-01

    Experiments are planned to study plasma lensing using the VELA and CLARA Front End accelerators at Daresbury Laboratory. This paper presents results of 2-dimensional particle-in-cell simulations of the proposed experiments. The variation in focusing strength and emittance growth with beam and plasma parameters are studied in the overdense (plasma density much greater than bunch density) regime for the VELA beam. The effect of spherical and longitudinal aberrations on the beam emittance was estimated through numerical and theoretical studies. Simulation results show that a focusing strength equivalent to a magnetic field gradient of 10 T m-1 can be achieved using VELA, and a gradient of 247 T m-1 can be achieved using CLARA Front End.

  6. High-Density Plasma Etching of Group-III Nitride Films for Device Application

    SciTech Connect

    Baca, A.G.; Crawford, M.H.; Han, J.; Lester, L.F.; Pearton, S.J.; Ren, F.; Shul, R.J.; Willison, C.G.; Zhang, L.; Zolper, J.C.

    1999-02-17

    As III-V nitride device structures become more complicated and design rules shrink, well-controlled etch processes are necessary. Due to limited wet chemical etch results for the group-III nitrides, a significant amount of effort has been devoted to the development of dry etch processing. Dry etch development was initially focused on mesa structures where high etch rates, anisotropic profiles, smooth sidewalls, and equi-rate etching of dissimilar materials were required. For example, commercially available LEDs and laser facets for GaN-based laser diodes have been patterned using reactive ion etching (RIE). With the recent interest in high power, high temperature electronic devices, etch characteristics may also require smooth surface morphology, low plasma-induced damage, and selective etching of one layer over another. The principal criteria for any plasma etch process is its utility in the fabrication of a device. In this study, we will report