Science.gov

Sample records for plasma study applications

  1. 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

  2. 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

  3. 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.

  4. Methods of Plasma Turbulence Analysis: Application to Shock Studies

    SciTech Connect

    Balikhin, M.A.; Walker, S.N.

    2005-08-01

    The availability of multisatellite observations (e.g. ISEE, AMPTE, and Cluster) has triggered the development of new methods of analysis to shed light on the complex dynamics inherent in the solar wind and magnetosphere. This paper looks at the results of two such methods. Firstly, the phase differencing method is used to determine the properties of waves observed upstream of a quasiperpendicular bow shock. The resulting dispersion relation is then interpreted as evidence that the waves are generated as a result of the dynamics of the shock front. The second, NARMAX, is used to investigate the linear and nonlinear processes if the plasma observed at a antiparallel shock. The results show that for a small amplitude whistler wavetrain, third order nonlinear interactions are only important at the interface between the shocklet and the wavetrain. For higher amplitude wavetrains, the phase of the linear term describing the plasma is shifted.

  5. Laser Diagnostics Study of Plasma Assisted Combustion for Scramjet Applications

    DTIC Science & Technology

    2011-12-01

    future. The combustion process in these engines typically involves highly turbulent reactive flow conditions, often beyond the limits of our...electric field gives rise to new electron and ion impact processes which can enhance the propagation and branching of radicals and ultimately...is generated separately and the flame is ignited as the gases pass over the plasma region. The actual oxidation process occurs further downstream

  6. Application of optical emission spectroscopy for the SNS H- ion source plasma studies

    NASA Astrophysics Data System (ADS)

    Han, B. X.; Stockli, M. P.; Welton, R. F.; Murray, S. N.; Pennisi, T. R.; Santana, M.

    2015-04-01

    The SNS H- ion source is a dual-frequency RF-driven (13.56-MHz low power continuous RF superimposed by 2-MHz high power pulsed RF with ˜1.0 ms pulse length at 60 Hz), Cs-enhanced ion source. This paper discusses the applications of optical emission spectroscopy for the ion source plasma conditioning, cesiation, failure diagnostics, and studies of plasma build-up and outage issues.

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

    PubMed

    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.

  8. 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.

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

    SciTech Connect

    Jahanbakhsh, Sina Satir, Mert; Celik, Murat

    2016-02-15

    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.

  10. Plasma pharmacy - physical plasma in pharmaceutical applications.

    PubMed

    von Woedtke, Th; Haertel, B; Weltmann, K-D; Lindequist, U

    2013-07-01

    During the last years the use of physical plasma for medical applications has grown rapidly. A multitude of findings about plasma-cell and plasma-tissue interactions and its possible use in therapy have been provided. One of the key findings of plasma medical basic research is that several biological effects do not result from direct plasma-cell or plasma-tissue interaction but are mediated by liquids. Above all, it was demonstrated that simple liquids like water or physiological saline, are antimicrobially active after treatment by atmospheric pressure plasma and that these effects are attributable to the generation of different low-molecular reactive species. Besides, it could be shown that plasma treatment leads to the stimulation of specific aspects of cell metabolism and to a transient and reversible increase of diffusion properties of biological barriers. All these results gave rise to think about another new and innovative field of medical plasma application. In contrast to plasma medicine, which means the direct use of plasmas on or in the living organism for direct therapeutic purposes, this field - as a specific field of medical plasma application - is called plasma pharmacy. Based on the present state of knowledge, most promising application fields of plasma pharmacy might be: plasma-based generation of biologically active liquids; plasma-based preparation, optimization, or stabilization of - mainly liquid - pharmaceutical preparations; support of drug transport across biological barriers; plasma-based stimulation of biotechnological processes.

  11. Laser-based diagnostics applications for plasma-surface interaction studies

    NASA Astrophysics Data System (ADS)

    van der Meiden, H. J.; van den Berg, M. A.; Brons, S.; Ding, H.; van Eck, H. J. N.; 't Hoen, M. H. J.; Karhunen, J.; de Kruif, T. M.; Laan, M.; Li, C.; Lissovski, A.; Morgan, T. W.; Paris, P.; Piip, K.; van de Pol, M. J.; Scannell, R.; Scholten, J.; Smeets, P. H. M.; Spork, C.; Zeijlmans van Emmichoven, P. A.; Zoomers, R.; De Temmerman, G.

    2013-11-01

    Several laser based diagnostics are implemented on to the linear plasma generator Magnum-PSI, wherein ITER divertor relevant plasma-wall conditions are realized. Laser Induced Desorption Quadrupole Mass Spectroscopy (LID-QMS) and Laser Induced Breakdown Spectroscopy (LIBS) are installed to measure deuterium retention in plasma facing components. Combined with Thermal Desorption Spectroscopy, LID-QMS can be used to measure lateral retention profiles. LIBS is used to measure the surface composition qualitatively, after plasma exposure. An advanced Thomson Scattering (TS) system measures electron density, neutral density and electron temperature profiles (spatial resolution < 2 mm) across the maximum 100 mm plasma diameter. Very low electron density (9 × 1018 m-3) can be measured within seconds with accuracies better than 6%. The minimum measurable electron density and temperature are ~ 1 × 1017 m-3 and ~ 0.07 eV, respectively. By virtue of the high system sensitivity, single pulse TS can be performed on high density pulsed plasmas (used for replicating ELMs). For measuring the ion temperature and flow velocity of the plasma a Collective TS system (CTS) is being built: the small Debye length of the Magnum-PSI plasma enables application of this method at relatively short laser wavelength. In a feasibility study it was shown that forward CTS with a seeded Nd:YAG laser operating at 1064 nm, can be applied at Magnum-PSI to measure ion temperature and axial velocity with an accuracy of < 8% and < 15%, respectively. Two high spectral resolution ( ~ 0.005 nm) detection schemes are applied simultaneously: an Echelle grating spectrometer (enabling profile measurements) and a system based on a Fabry-Perot etalon that enables wavelength scanning over its free spectral range, by tilting the device. The status and performance of the various laser based plasma and surface diagnostics will be reported along with experimental results.

  12. Validated HPLC method for determination of caffeine level in human plasma using synthetic plasma: application to bioavailability studies.

    PubMed

    Alvi, Syed N; Hammami, Muhammad M

    2011-04-01

    Several high-performance liquid chromatography (HPLC) methods have been described for the determination of caffeine in human plasma. However, none have been cross validated using synthetic plasma. The present study describes a simple and reliable HPLC method for the determination of the caffeine level in human plasma. Synthetic plasma was used to construct calibration curves and quality control samples to avoid interference by caffeine commonly present in donor's human plasma. After deproteination of plasma samples with perchloric acid, caffeine and antipyrine (internal standard, IS) were separated on a Waters Atlantis C18 column using a mobile phase of 15 mM potassium phosphate (pH 3.5) and acetonitrile (83:17, v/v), and monitored by photodiode array detector, with the wavelength set at 274 nm. The relationship between caffeine concentrations and peak area ratio (caffeine-IS) was linear over the range of 0.05-20 μg/mL. Inter-run coefficient of variation was ≤ 5.4% and ≤ 6.0% and bias was ≤ 3% and ≤ 7% using human and synthetic plasma, respectively. Mean extraction recovery from human plasma of caffeine and the IS was 91% and 86%, respectively. Caffeine in human plasma was stable for at least 24 h at room temperature or 12 weeks at -20 °C, and after three freeze-thaw cycles. The method was successfully applied to monitor caffeine levels in healthy volunteers with correction of caffeine levels using the mean ratio of the slopes of the calibration's curves constructed using human and synthetic plasma.

  13. 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.

  14. 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.

  15. Comparative study of CF4- and CHF3-based plasmas for dry etching applications

    NASA Astrophysics Data System (ADS)

    Efremov, A.; Kwon, K.-H.; Morgunov, A.; Shabadarova, D.

    2016-12-01

    The influence of O2/Ar mixing ratio on plasma characteristics, densities and fluxes of active species determining the dry etching kinetics in both CF4/O2/Ar and CHF3/O2/Ar plasmas was studied. The investigation combined plasma diagnostics by Langmuir probes and zero-dimensional plasma modeling. It was found that the substitution of O2 for Ar at constant fraction of CF4 or CHF3 in a feed gas noticeably changes electron temperature and electron density, but does not result in the non-monotonic behavior of F atom density. The differences between two gas systems were discussed in details from the point of view of plasma chemistry.

  16. Laboratory study of pulsed regimes of electron cyclotron instabilities in a mirror-confined plasma for astrophysical applications

    NASA Astrophysics Data System (ADS)

    Viktorov, Mikhail; Golubev, Sergey; Mansfeld, Dmitry; Izotov, Ivan; Gospodchikov, Egor; Shalashov, Alexander; Demekhov, Andrei

    2014-05-01

    We discuss the use of a mirror-confined plasma of the electron cyclotron resonance discharge for modeling of burst processes in the inner magnetosphere of the Earth associated with the implementation of the plasma cyclotron maser. Heating under the electron cyclotron resonance conditions allows to create two component plasma which is typical for the inner magnetosphere of the Earth. One of the most interesting electron cyclotron resonance manifestations is the generation of bursts of electromagnetic radiation that are related to the explosive growth of cyclotron instabilities of the magnetoactive plasma confined in magnetic traps of various kinds and that are accompanied by particle precipitations from the trap. We investigate several regimes of cyclotron maser which are realized in dense and rarefied plasma, in the presence and absence of a permanent powerful gyrotron microwave radiation as a source of nonequilibrium particles in the plasma. Using the new technique for detection of microwave radiation we studied the dynamical spectrum and the intensity of stimulated electromagnetic radiation from the plasma in a wide frequency band covering all types of cyclotron instabilities. Also possible applications for astrophysical plasma are discussed.

  17. A comprehensive investigation of halogenated plasmas: From mechanistic studies to applications

    NASA Astrophysics Data System (ADS)

    Martin, Ina Taylor

    2005-12-01

    Octafluoropropane (C3F8) and octafluorocyclobutane (C4F8) plasmas were used to deposit thin fluorocarbon (FC) films on Si substrates. The effects of applied rf power (P), substrate position and pulsing the plasma on film composition and thickness were studied. Plasma parameters that limited ion bombardment of the substrate during film deposition, such as pulsing the plasma, and placing the substrate downstream from the source, resulted in more F rich, less crosslinked materials. After developing the FC deposition systems, a C3F8 plasma treatment was chosen to modify polymer microfluidic devices, with the intent of coating the device with a non-ionizable film to reduce the electroosmotic flow (EOF). Acrylic acid (AA) plasmas were also used to treat the microfluidic devices. Both treatments resulted in modified EOF flow values compared to untreated devices. Plasma treated substrates were analyzed using FTIR, X-ray photoelectron spectroscopy (XPS), scanning Auger microcopy (SAM), scanning electron microscopy (SEM), and ellipsometry. Gas-phase studies were performed using laser-induced fluorescence (LIF) and mass spectrometry with energy analysis capabilities. Gas-surface interaction studies of CF2 molecules in these FC systems were performed using our imaging of radicals interacting with surfaces (IRIS) technique, with an emphasis on ion effects. High scattering coefficients (S > 1) indicate CF2 molecules are generated at the surface. Ions were found to contribute to the surface production of CF2 during FC plasma treatment of Si. Specifically, a linear correlation exists between CF2 surface production and the mean energy of ions produced in the plasma. There is also a linear correlation present between S (CF2) values measured and the degree of crosslinking in the deposited FC materials. Additionally, relative density measurements and rotational temperature studies of CF are discussed. This dissertation also summarizes preliminary work involving tetrachlorosilane (Si

  18. Plasma core reactor applications

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    Analytical and experimental investigations were conducted to demonstrate the feasibility of fissioning uranium plasma core reactors and to characterize space and terrestrial applications for such reactors. Uranium hexafluoride fuel is injected into core cavities and confined away from the surface by argon buffer gas injected tangentially from the peripheral walls. Radiant heat transfer calculations were performed for a six-cavity reactor configuration. Axial working fluid channels are located along a fraction of each cavity peripheral wall. Results of calculations for outward-directed radiant energy fluxes corresponding to radiating temperatures of 2000 to 5000 K indicate total operating pressures from 80 to 650 atm, centerline temperatures from 6900 to 30,000 K, and total radiated powers from 25 to 2500 MW, respectively. Applications are described for this type of reactor such as (1) high-thrust, high specific impulse space propulsion, (2) highly efficient systems for generation of electricity, and (3) hydrogen or synthetic fuel production systems using the intense radiant energy fluxes.

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

    SciTech Connect

    Djuth, F.T.; Elder, J.H.; Sulzer, M.P.

    1994-12-01

    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. The authors 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 {approximately} 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 ({ge} 5 eV) can be deduced. The earliest measurements are used to illustrate applications of the coded long-pulse technique to several aeronomic/ionospheric 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. 14 refs., 4 figs., 1 tab.

  20. 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.

  1. 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.

  2. Studies of ionospheric plasma and electrodynamics and their application to ionosphere-magnetosphere coupling

    NASA Technical Reports Server (NTRS)

    Heelis, R. A.

    1988-01-01

    The contribution of the Dynamics Explorer (DE) program to the study of small-scale structure in the equatorial ionospheric number density and the bulk motion of the plasma in the equatorial ionosphere is considered. DE results have helped elucidate the role of E region and F region winds in decreasing the magnitude of variations in the east-west plasma drift at night, as a function of magnetic flux tube apex height, with increasing height above the altitude of the peak F region concentration. Other results concern the ionospheric convection pattern at high latitudes during periods of southward IMF, the magnetosphere/solar-wind interaction that may be involved in the production of the convection pattern, and the characteristics of the high-latitude ionospheric plasma motion during periods of northward IMF.

  3. 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.

  4. 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.

  5. Application of spectral line shapes to the study of high density ICF plasmas

    SciTech Connect

    Keane, C.J.; Hammel, B.A.; Langer, S.H.; Lee, R.W.; Calisti, A.; Godbert, L.; Stamm, R.; Talin, B.

    1994-09-01

    Spectral line broadening manifests itself in the study of high density inertial confinement fusion (ICF) plasmas in two important ways. First, comparison between measured and calculated lineshapes of individual spectral lines or groups of lines is used to diagnose plasma conditions in dense ICF plasmas, particularly in implosions. Secondly, through the emission and absorption coefficients spectral lineshapes serve as important inputs to plasma spectroscopy simulation codes which calculate simulated spectra from ICF targets. We discuss recent results from each of these areas. With regard to lineshape diagnostics, the advent of generalized line broadening codes has allowed the line profiles of complex multielectron emitters to be considered for diagnostic purposes. Particular example of this is the use of Ar He-{beta} and its associated dielectronic satellites as a diagnostic of T{sub e} and N{sub e}, as well as the development of Ne-like Xe line broadening as a density diagnostic. With respect to simulation codes, the implementation of detailed lineshapes in calculations of this type is in many ways in its infancy. We present here examples of cases where effects related to spectral lineshapes such as continuum lowering and line transfer of Stark broadened lines are important so as to provide a stimulus for future work in this field. 34 refs., 9 figs., 1 tab.

  6. 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.

  7. Quantitation of metformin in human plasma and urine by hydrophilic interaction liquid chromatography and application to a pharmacokinetic study.

    PubMed

    Nielsen, Flemming; Christensen, Mette M H; Brøsen, Kim

    2014-04-01

    We describe an analytical method for the quantification of the widely used antihyperglycemic agent, metformin, in human plasma and urine. The separation was performed using isocratic hydrophilic interaction liquid chromatography on a Luna hydrophilic interaction liquid chromatography column (125 × 4.6 mm, 3 μm). The sample preparation was accomplished by solid-phase extraction. Validation of the method was performed in the range 10-2000 ng/mL for plasma and 5-30 mcg/mL for urine. The methods were linear within the investigated range (r(2) > 0.988). Within-day repeatability ranged from 3.1% to 7.5% in plasma and 1.6% to 6.2% in urine. Between-day reproducibility ranged from 2.9% to 5.3% in plasma and 0.6% to 1.8% in urine. The inaccuracy expressed as bias ranged from -3.1% to 1.9% in plasma and from -7.2% to 0.7% in urine. The lower limit of quantification for metformin in plasma was 5 ng/mL and in urine was 40 ng/mL. The method was therefore considered to be precise, accurate, reproducible, and sensitive enough to be appropriate for pharmacokinetic studies of metformin. The applicability of the method for human pharmacokinetic studies was demonstrated by dosing a healthy male volunteer with 500-mg metformin hydrochloride as a single oral dose; plasma and urine concentrations were measured for 24 hours.

  8. Aerospace applications of pulsed plasmas

    NASA Astrophysics Data System (ADS)

    Starikovskiy, Andrey

    2012-10-01

    The use of a thermal equilibrium plasma for combustion control dates back more than a hundred years to the advent of internal combustion (IC) engines and spark ignition systems. The same principles are still applied today to achieve high efficiency in various applications. Recently, the potential use of nonequilibrium plasma for ignition and combustion control has garnered increasing interest due to the possibility of plasma-assisted approaches for ignition and flame stabilization. During the past decade, significant progress has been made toward understanding the mechanisms of plasma chemistry interactions, energy redistribution and the nonequilibrium initiation of combustion. In addition, a wide variety of fuels have been examined using various types of discharge plasmas. Plasma application has been shown to provide additional combustion control, which is necessary for ultra-lean flames, high-speed flows, cold low-pressure conditions of high-altitude gas turbine engine (GTE) relight, detonation initiation in pulsed detonation engines (PDE) and distributed ignition control in homogeneous charge-compression ignition (HCCI) engines, among others. The present paper describes the current understanding of the nonequilibrium excitation of combustible mixtures by electrical discharges and plasma-assisted ignition and combustion. Nonequilibrium plasma demonstrates an ability to control ultra-lean, ultra-fast, low-temperature flames and appears to be an extremely promising technology for a wide range of applications, including aviation GTEs, piston engines, ramjets, scramjets and detonation initiation for pulsed detonation engines. To use nonequilibrium plasma for ignition and combustion in real energetic systems, one must understand the mechanisms of plasma-assisted ignition and combustion and be able to numerically simulate the discharge and combustion processes under various conditions.

  9. [Application of atomic emission spectroscopy analysis in the atmospheric pressure plasma polishing process study].

    PubMed

    Wang, Bo; Zhang, Ju-Fan; Dong, Shen

    2008-07-01

    The atmospheric pressure plasma polishing (APPP) is a novel precision machining technology. It performs the atom scale material removal based on low temperature plasma chemical reactions. As the machining process is chemical in nature, it avoids the surface/subsurface defects usually formed in conventional mechanical machining processes. APPP firstly introduces a capacitance coupled radio frequency (RF) plasma torch to generate reactive plasma and excite chemical reactions further. The removal process is a complicated integrating action which tends to be affected by many factors, such as the gas ratio, the RF power and so on. Therefore, to improve the machining quality, all the aspects should be considered and studied, to establish the foundation for further model building and theoretical analysis. The atomic emission spectroscopy analysis was used to study the process characteristics. A commercial micro spectrometer was used to collect the spectrograms under different parameters, by comparing which the influence of the RF power and gas ratio was initially studied. The analysis results indicate that an increase in RF power results in a higher removal rate within a certain range. The gas ratio doesn't show obvious influence on the removal rate and surface roughness in initial experiments, but the element compositions detected by X-ray photoelectron spectroscopy technology on the machined surfaces under different ratios really indicate distinct difference. Then the theoretical analysis revealed the corresponding electron transition orbits of the excited reactive fluorine atoms, which is necessary for further mechanism research and apparatus improvement. Then the initial process optimization was made based on the analysis results, by which the Ra 0.6 nm surface roughness and 32 mm3 x min(-1) removal rate were achieved on silicon wafers.

  10. 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.

  11. Comparative study of non-thermal atmospheric pressure discharge plasmas for life science applications

    NASA Astrophysics Data System (ADS)

    Koga, Kazunori; Katayama, Ryu; Sarinont, Thapanut; Seo, Hyunwoong; Itagaki, Naho; Attri, Pankaj; Leal-Quiros, Edbertho; Tanaka, Akiyo; Shiratani, Masaharu

    2016-09-01

    We are comparing several non-thermal atmospheric pressure discharge plasmas for life science applications. Here we measured discharge period dependence of pH value and 750 nm absorbance of KI-starch solution of deionized water after plasma irradiation with two discharge devices; a dielectric barrier discharge (DBD) jet device and a scalable DBD device. The pH and the absorbance of KI-starch solution are useful indicator of their oxidizability. We have obtained a map of the absorbance and proton concentration [H+] which is deduced from pH value. For the scalable DBD, the range of the absorbance is between 0.7 and 1.3 and that of [H+] is between 10-7 and 10-5 mol/L. For the DBD jet, the range of the absorbance and [H+] are 2.0-3.2 and 10-4-10-3 mol/L, respectively. Measured data for both devices shows same tendency in the map, while the range of values for the scalable DBD is smaller than that for the DBD jet. The results indicate the oxidazability for the scalable DBD is much weaker than that for the DBD jet.

  12. HPLC-UV determination of metformin in human plasma for application in pharmacokinetics and bioequivalence studies.

    PubMed

    Porta, Valentina; Schramm, Simone Grigoleto; Kano, Eunice Kazue; Koono, Eunice Emiko; Armando, Yara Popst; Fukuda, Kazuo; Serra, Cristina Helena Dos Reis

    2008-01-07

    In this study, a simple, rapid and sensitive HPLC method with UV detection is described for determination of metformin in plasma samples from bioequivalence assays. Sample preparation was accomplished through protein precipitation with acetonitrile and chromatographic separation was performed on a reversed-phase phenyl column at 40 degrees C. Mobile phase consisted of a mixture of phosphate buffer and acetonitrile at flow rate of 1.0 ml/min. Wavelength was set at 236 nm. The method was applied to a bioequivalence study of two drug products containing metformin, and allowed determination of metformin at low concentrations with a higher throughput than previously described methods.

  13. 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

  14. 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.

  15. Quantification of mesembrine and mesembrenone in mouse plasma using UHPLC-QToF-MS: Application to a pharmacokinetic study.

    PubMed

    Manda, Vamshi K; Avula, Bharathi; Ashfaq, Mohammad K; Abe, Naohito; Khan, Ikhlas A; Khan, Shabana I

    2017-03-01

    Sceletium tortuosum, is an indigenous herb of South Africa which is widely used as an herbal supplement in the treatment of anxiety and stress. Mesembrenone and mesembrine are the two main pharmacologically active alkaloids present in the extract. Despite the wide therapeutic applications of Sceletium extract, there are no reports of in vivo pharmacokinetic properties or analytical methods to quantify these two important alkaloids in plasma. Therefore, the current study aimed to develop and validate a simple and sensitive analytical method for simultaneous quantification of mesembrenone and mesembrine in mouse plasma. Ultra-high-performance liquid chromatography-mass spectrometry (UHPLC/QToF-MS) was employed to achieve our objectives. The compounds were extracted using protein precipitation by methanol (100%) with quinine as an internal standard. The lower limit of quantification for both the compounds was 10 ng/mL. The extraction recovery was between 87 and 93% for both compounds with no matrix effects on the analysis. The accuracy was between 89.5 and 106% and precision was <12.6% for all quality control samples. This validated method was successfully applied to evaluate the i.v. plasma pharmacokinetics of mesembrine and mesembrenone in mouse. However, the oral bioavailability of these alkaloids was poor and the plasma levels were below the detection limits.

  16. [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.

  17. Determination of dimenhydrinate in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to a relative bioavailability study.

    PubMed

    Tavares, V; Macedo, C C; Montanhez, L; Barros, F A P; Meurer, E C; Campos, D R; Coelho, E C; Calaffati, S A; Pedrazzoli, J

    2007-06-15

    Here we present a sensitive and specific liquid chromatography-tandem mass spectrometric method for the quantification of dimenhydrinate (I) in human plasma. Sample preparation is conducted using citalopram (II) addition as an internal standard (IS), liquid-liquid extraction with basified plasma using a mixture hexane/acetate (1:1, v/v) as the extracting solvent, and the final extract reconstituted in the mobile phase. I and II (IS) were injected in a C8 column with the mobile phase composed of methanol:isopropanol:water:formic acid (78.00:19.92:2.00:0.08, v/v/v/v) and monitored using a positive electrospray source with tandem mass spectrometry analyses. The selected reaction monitoring (SRM) was set using precursor ion and product ion combinations of m/z 256.0>167.0 and m/z 325.0>109.0 for I and II, respectively. The limit of quantification (LOQ) was 0.4 ng/mL, the dynamic range being 0.4-200 ng/mL. Validation results on linearity, specificity, accuracy, precision and stability, as well as on application to the analysis of plasma samples taken up to 24 h after oral administration of 100 mg of dimenhydrinate in healthy volunteers demonstrated its applicability to bioavailability studies.

  18. 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.

  19. 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.

  20. Analysis of nabumetone in human plasma by HPLC. Application to single dose pharmacokinetic studies.

    PubMed

    Kobylińska, Kamila; Barlińska, Małgorzata; Kobylińska, Maria

    2003-06-01

    A simple and sensitive high performance liquid chromatography method for the determination of nabumetone in human plasma is described. The procedure involves liquid-liquid extraction with ethyl acetate and reversed-phase chromatography with fluorimetric detection (excitation 230 nm, emission 356 nm). The chromatographic conditions and the extraction procedure gave a clean chromatogram for the compound. The limit of quantitation was established as 0.313 ng/ml and the calibration curve was linear up to 20 ng/ml. The within-day and between-day relative standard deviations were less than 10% and the accuracy of the assay was in the range of 99-104%. The suitability of the method is shown for pharmacokinetic studies.

  1. Laboratory studies of stagnating plasma flows with applications to inner solar system and stellar bow shocks

    NASA Astrophysics Data System (ADS)

    Weber, T. E.; Smith, R. J.; Hsu, S. C.

    2016-10-01

    Supercritical magnetized collisionless shocks are thought to play a dominant role in the overall partition of energy throughout the universe by converting flow kinetic energy to other forms such as thermal and supra-thermal populations, magnetic field enhancement, turbulence, and energetic particles. The Magnetized Shock Experiment (MSX) at LANL creates conditions similar to those of inner solar system and stellar bow shocks by accelerating hot (100s of eV during translation) dense (1022 - 1023 m-3) Field Reversed Configuration (FRC) plasmoids to 100s of km/s; resulting in β 1, collisionless plasma flows with Msonic and MAlfvén 10. The drifting FRC can be made to impinge upon a variety of static obstacles including: a strong mirror or cusp magnetic field (mimicking magnetically excited shocks such as the Earth's bow shock), plasma pileup from a solid obstacle (similar to the bow shocks of Mercury and the Moon), and a neural gas puff (bow shocks of Venus or the comets). Characteristic shock length and time scales that are both large enough to observe yet small enough to fit within the experiment, enabling study of the complex interplay of kinetic and fluid processes that mediate cosmic shocks and can generate non-thermal distributions, produce density and magnetic field enhancements much greater than predicted by fluid theory, and accelerate particles. An overview of the experimental program will be presented, including recent results. This work is supported by the U.S. DOE, Office of Science, Office of Fusion Energy Sciences under Contract No. DE-AC52-06NA25369.

  2. Plasma focus: Present status and potential applications

    SciTech Connect

    Brzosko, J.S.; Nardi, V.; Powell, C.

    1997-12-01

    Initially, dense plasma focus (DPF) machines were constructed independently by Filippov in Moscow and Mather in Los Alamos at the end of the 1950s. Since then, more than 30 laboratories have carried vigorous DPF programs, oriented mainly toward the studies of physics of ion acceleration and trapping in the plasma focus environment. Applications of the DPF as intense neutron and X-ray sources have been recognized since its discovery but not implemented for various reasons. Recently, some groups (including AES) addressed the issue of DPF applications, and some of them are briefly discussed in this paper.

  3. Application of liquid chromatography method with electrochemical detection for bioequivalence study of trimetazidine in human plasma.

    PubMed

    Grabowski, Tomasz; Swierczewska, Anna; Borucka, Beata; Sawicka, Renata; Sasinowska-Motyl, Małgorzata; Gumułka, Stanisław Witold

    2012-01-01

    A method to estimate trimetazidine (CAS: 13171-25-0) levels in human plasma by means of HPLC with electrochemical detection was developed. Trimethoprim (CAS: 26807-65-8) was used as an internal standard. This method of analysis was fully validated according to the guidelines of the United States Food and Drug Administration, European Medicines Agency and Organization for Economic Co-operation and Development and Good Laboratory Practice rules. The accuracy and precision of the developed method were found to be satisfactory and stability studies showed acceptable variation (below 15%) of trimetazidine concentrations when samples were stored frozen at -75 degrees C for 54 days. The developed method was successfully used for a comparative 2 x 2 period, crossover bioequivalence study of two extended-release preparations of trimetazidine performed on 24 healthy volunteers at the steady state after multiple dosing of 35 mg twice daily for 4 days and a single 35 mg dose on the 5th day and after a single dose of 35 mg under fasting or postprandial conditions.

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    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.

  5. 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.

  6. Determination of levocetirizine in human plasma by liquid chromatography-electrospray tandem mass spectrometry: application to a bioequivalence study.

    PubMed

    Morita, M R; Berton, D; Boldin, R; Barros, F A P; Meurer, E C; Amarante, A R; Campos, D R; Calafatti, S A; Pereira, R; Abib, E; Pedrazolli, J

    2008-02-01

    We describe a liquid chromatography-tandem mass spectrometric method (LC-MS/MS) for levocetirizine quantification (I) in human plasma. Sample preparation was made using a fexofenadine (II) addition as internal standard (IS), liquid-liquid extraction using cold dichloromethane, and dissolving the final extract in acetonitrile. I and II (IS) were injected in a C18 column and the mobile phase composed of acetonitrile:water:formic acid (80.00:19.90:0.10, v/v/v) and monitored using positive electrospray source with tandem mass spectrometry analyses. The selected reaction monitoring (SRM) was set using precursor ion and product ion combinations of m/z 389>201 for I and m/z 502>467 for II. The limit of quantification and the dynamic range achieved were 0.5ng/mL and 0.5-500.0ng/mL. Validation results on linearity, specificity, accuracy, precision and stability, as well as its application to the analysis of plasma samples taken up to 48h after oral administration of 5mg of levocetirizine dichloridrate in healthy volunteers demonstrate its applicability to bioavailability studies.

  7. Application of Laser-Generated Ion Beams for Isochoric Heating to Study Plasma Mix at Interfaces

    NASA Astrophysics Data System (ADS)

    Albright, B. J.; Fernández, J. C.; Bang, W.; Bradley, P. A.; Gautier, D. C.; Hamilton, C. E.; Palaniyappan, S.; Santiago Cordoba, M. A.; Vold, E. L.; Yin, L.; Hegelich, B. M.; Dyer, G.; Roycroft, R.

    2015-11-01

    The evolution and mixing of high-Z/low-Z interfaces in plasma media is of profound importance to high energy density physics and inertial fusion experiments. Recent experiments performed at the LANL Trident laser facility as part of the Plasma Interfacial Mix project have applied novel, laser-generated ion beams created under conditions of relativistic induced transparency to the heating of solid-density, multi-material targets isochorically and uniformly (over a few tens of ps), attaining plasma temperatures of several eV. Measurements have been made of the evolving plasma, including location of the material interface and the time-history of the temperature of the medium. Recent data and associated radiation hydrodynamic modeling from our Trident campaigns will be reported. Complementary kinetic simulations of interface evolution, showing anomalously rapid atomic mixing under conditions relevant to ICF experiments, will also be discussed. Work performed under the auspices of the U.S. DOE by the LANS, LLC, Los Alamos National Laboratory under Contract No. DE-AC52-06NA25396. Funding provided by the Los Alamos National Laboratory Directed Research and Development Program.

  8. An UPLC-MS/MS method for the quantitation of vortioxetine in rat plasma: Application to a pharmacokinetic study.

    PubMed

    Gu, Er-min; Huang, Chengke; Liang, Bingqing; Yuan, Lingjing; Lan, Tian; Hu, Guoxin; Zhou, Hongyu

    2015-08-01

    In this work, a simple, sensitive and fast ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitative determination of vortioxetine in rat plasma. Plasma samples were processed with a protein precipitation. The separation was achieved by an Acquity UPLC BEH C18 column (2.1mm×50mm, 1.7μm) column with a gradient mobile phase consisting of 0.1% formic acid in water and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring (MRM). The validated method had an excellent linearity in the range of 0.05-20ng/mL (R(2)>0.997) with a lower limit of quantification (0.05ng/mL). The extraction recovery was in the range of 78.3-88.4% for vortioxetine and 80.3% for carbamazepine (internal standard, IS). The intra- and inter-day precision was below 8.5% and accuracy was from -11.2% to 9.5%. No notable matrix effect and astaticism was observed for vortioxetine. The method has been successfully applied to a pharmacokinetic study of vortioxetine in rats for the first time, which provides the basis for the further development and application of vortioxetine.

  9. Atmospheric pressure plasma jet applications

    SciTech Connect

    Park, J.; Herrmann, H.W.; Henins, I.; Selwyn, G.S.

    1998-12-31

    The atmospheric pressure plasma jet (APPJ) is a non-thermal, high pressure plasma discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g., He/O2/H2O) which flows between two concentric cylindrical electrodes: an outer grounded electrode and an inner electrode powered at 13.56 MHz RF. While passing through the plasma, the feedgas becomes excited, ionized or dissociated by electron impact. The fast-flowing effluent consists of ions and electrons, which are rapidly lost by recombination, highly reactive radicals (e.g., O, OH), and metastable species (e.g., O2). The metastable O2, which is reactive to hydrocarbon and other organic species, has been observed through optical emission spectroscopy to decrease by a factor of 2 from the APPJ nozzle exit to a distance of 10 cm. Unreacted metastable O2, and that which does not impinge on a surface, will then decay back to ordinary ground state O2, resulting in a completely dry, environmentally-benign form of surface cleaning. Applications such as removal of photoresist, oxide films and organic residues from wafers for the electronics industry, decontamination of civilian and military areas and personnel exposed to chemical or biological warfare agents, and paint (e.g., graffiti) removal are being considered.

  10. LC-MS/MS determination of etravirine in rat plasma and its application in pharmacokinetic studies.

    PubMed

    Abobo, Cyril V; Wu, Lei; John, Jyothy; Joseph, Mathew K; Bates, Theodore R; Liang, Dong

    2010-11-15

    Etravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that is active against NNRT-resistant HIV-1. A simple, sensitive, and specific LC-MS/MS method was developed and validated for the analysis of etravirine in rat plasma using itraconazole as the internal standard. The analytes were extracted with ethyl acetate and chromatographed on a reverse-phase XTerra MS C₁₈ column. Elution was achieved with a mobile phase gradient varying the proportion of a 2 mM ammonium acetate aqueous solution containing 0.1% formic acid (solvent A) and a 0.1% formic acid in methanol solution (solvent B) at a flow rate of 300 μL/min. The analytes were monitored by tandem-mass spectrometry with positive electrospray ionization. The precursor/product transitions (m/z) in the positive ion mode were 435.9→163.6 and 706.7→392.6 for etravirine and the internal standard, respectively. Calibration curves were linear over the etravirine rat plasma concentration range of 1-100 ng/mL. The inter- and intra-day accuracy and precision were within ±10%. The assay has been successfully used for pharmacokinetic evaluation of etravirine using the rat as an animal model.

  11. LC-MS/MS determination of etravirine in rat plasma and its application in pharmacokinetic studies

    PubMed Central

    Abobo, Cyril; Wu, Lei; John, Jyothy; Joseph, Mathew K.; Bates, Theodore R.; Liang, Dong

    2010-01-01

    Etravirine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) that is active against NNRT-resistant HIV-1. A simple, sensitive, and specific LC-MS/MS method was developed and validated for the analysis of etravirine in rat plasma using itraconazole as the internal standard. The analytes were extracted with ethyl acetate and chromatographed on a reverse-phase XTerra MS C18 column. Elution was achieved with a mobile phase gradient varying the proportion of a 2 mM ammonium acetate aqueous solution containing 0.1% formic acid (solvent A) and a 0.1% formic acid in methanol solution (solvent B) at a flow rate of 300 μL/min. The analytes were monitored by tandem-mass spectrometry with positive electrospray ionization. The precursor/product transitions (m/z) in the positive ion mode were 435.9→163.6 and 706.7→392.6 for etravirine and the internal standard, respectively. Calibration curves were linear over the etravirine rat plasma concentration range of 1 ng/mL to 100 ng/mL. The inter- and intra-day accuracy and precision were within ±10%. The assay has been successfully used for pharmacokinetic evaluation of etravirine using the rat as an animal model. PMID:20965798

  12. Generation And Applications Of Electron-Beam Plasma Flows

    NASA Astrophysics Data System (ADS)

    Vasiliev, M. N.; Tun Win, Aung

    2015-03-01

    Plasma flows generated by continuous or interrupted injection of an electron beam into subsonic or supersonic gaseous streams are considered. Liquid and powder spraying by the electron-beam plasma (EBP) flows is studied as a technique of the aerosol plasma generation. A number of experimental setups generating both free plasma jets and plasma flows in channels are described. Examples of the EBP flows applications for industrial and aerospace technologies are given. The applications are shown to be based on unique properties of the EBP and its stability within very wide ranges of the plasma generation conditions. Some applications of the Hybrid Plasma (HP) generated by combined action of the electron beam (EB) and intermittent gas discharge on flows of gaseous mixtures and aerosols are presented as well.

  13. 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.

  14. 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.

  15. Application of capillary gas chromatography to the study of hydrolysis of the nerve agent VX in rat plasma.

    PubMed

    Bonierbale, E; Debordes, L; Coppet, L

    1997-01-24

    We present here a gas chromatography technique allowing the detection and quantification of VX [O-ethyl S-(2-diisopropylaminoethyl)methylphosphonothiolate] as well as its P-S bond hydrolysis product diisopropylaminoethanethiol directly from spiked rat plasma. This technique was applied to study VX hydrolysis in rat plasma. We observed that 53 +/- 4% of 374 microM VX disappeared from spiked plasma after 2 h. VX disappearance was mainly related to enzymatic cleavage of the P-S bond (Km = 2.5 mM and Vmax = 13.3 nmol min-1 ml-1 of rat plasma). The activity was totally inhibited by 1 mM Hg2+ and was also inhibited by metal chelators.

  16. Application of bicoherence analysis in study of wave interactions in space plasma

    SciTech Connect

    Lagoutte, D.; Lefeuvre, F. ); Hanasz, J. )

    1989-01-01

    A spectral analysis at the second order (power spectrum) loses the phase information among the different Fourier components. To retain this information, the bispectrum (third order) and/or the bicoherence (normalized bispectrum) are calculated. Application to simulated data, shows the dependence of the bispectrum to amplitudes of involved waves and of the bicoherence to signal-to-noise ratio. Bicoherence technique is applied in the analysis of harmonics produced by an electronic receiver, as well as in the investigation of phase coherence between a ground-transmitter signal, a natural ELF emission near the proton gyrofrequency, and the sidebands around the carrier. Strong arguments are provided that the sidebands are generated by a parametric interaction between the transmitter signal and the ELF emission.

  17. 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.

  18. Low temperature plasma applications in medicine

    NASA Astrophysics Data System (ADS)

    Weltmann, K.-D.; Metelmann, H.-R.; von Woedtke, Th.

    2016-11-01

    The main field of plasma medicine is the direct application of cold atmospheric plasma (CAP) on or in the human body for therapeutic purposes. CAP is effective both to inactivate a broad spectrum of microorganisms including multiple drug resistant ones and to stimulate proliferation of mammalian cells. Clinical application has started in the field of wound healing and treatment of infective skin diseases.

  19. 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).

  20. 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.

  1. Study of nanosecond discharges in different H2 air mixtures at atmospheric pressure for plasma-assisted applications

    NASA Astrophysics Data System (ADS)

    Bourdon, Anne; Kobayashi, Sumire; Bonaventura, Zdenek; Tholin, Fabien; Popov, Nikolay

    2016-09-01

    This paper presents 2D simulations of nanosecond pulsed discharges between two point electrodes in different H2/air mixtures and in air at atmospheric pressure. A fluid model is coupled with detailed kinetic schemes for air and different H2/air mixtures to simulate the discharge dynamics. First, as the positive and negative ionization waves propagate in the interelectrode gap, it has been observed that in H2/air mixtures with equivalence ratios between 0.3 and 2, major positive ions produced by the nanosecond discharge are N2+,O2+and HN2+.The discharge dynamics is shown to vary only slightly for equivalence ratios of the H2/air mixture between 0.3 and 2. Then, as the discharge transits to a nanosecond spark discharge, we have studied the different chemical reactions that lead to fast gas heating and to the production of radicals, as O,H and OH. Both thermal and chemical effects of the nanosecond spark discharge are of interest for plasma assisted combustion applications. This work has been supported by the project DRACO (Grant No. ANR-13-IS09-0004) and the french russian LIA Kappa.

  2. Novel and sensitive UPLC-MS/MS method for quantification of sofosbuvir in human plasma: application to a bioequivalence study.

    PubMed

    Rezk, Mamdouh R; Basalious, Emad B; Amin, Mohammed E

    2016-09-01

    A novel and sensitive LC-MS/MS method was developed and validated for determination of sofosbuvir (SF) using eplerenone as an internal standard. The Xevo TQD LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Extraction with tert-butyl methyl ether was used in sample preparation. The prepared samples were chromatographed on Acquity UPLC BEH C18 (50 × 2.1 mm, 1.7 μm) column by pumping 0.1% formic acid and acetonitrile in an isocratic mode at a flow rate of 0.35 mL/min. Method validation was performed as per the US Food and Drug Administration guidelines and the standard curves were found to be linear in the range of 0.25-3500 ng/mL for SF. The intra- and inter-day precision and accuracy results were within the acceptable limits. A very short run time of 1 min made it possible to analyze more than 500 human plasma samples per day. A very low quantification limit of SF allowed the applicability of the developed method for determination of SF in a bioequivalence study in human volunteers. Copyright © 2016 John Wiley & Sons, Ltd.

  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. Development and validation of a quantification method for cucurbitacins E and I in rat plasma: Application to population pharmacokinetic studies.

    PubMed

    Fiori, Giovana Maria Lanchoti; D'Agate, Salvatore; Rocha, Adriana; Pereira, Ana Maria Soares; Pasqua, Oscar Della; Lopes, Norberto Peporine

    2017-02-20

    Cucurbitacin E is a potential drug candidate due to its anticancer activity, recognition of its molecular targets, and synergism with other drugs used for cancer treatment. However, the use of cucurbitacin E in clinical practice is not possible because of important knowledge gaps in its preclinical and clinical pharmacokinetic characteristics. Cucurbitacin E is hydrolyzed to cucurbitacin I in plasma and in human liver microsomes. The aim of this study was to evaluate the population pharmacokinetics of cucurbitacin E and of its metabolite cucurbitacin I in rats. The method for the sequential analysis of cucurbitacins E and I in rat plasma was developed using LC-MS/MS. Plasma aliquots of 50μL were deproteinized with acetonitrile and clobazam was added as internal standard. The extracts were injected into an RP-18 column and eluted with a mobile phase consisting of a mixture of acetonitrile:water:methanol (32:35:33, v/v/v). The method was precise and accurate, showing linearity in the range of 1-100ng cucurbitacin E/mL plasma and of 0.4-200ng cucurbitacin I/mL plasma. The method was applied to the pharmacokinetic evaluation of cucurbitacin E administered intravenously to male Wistar rats (1mg/kg). Serial blood samples were collected up to 24h after administration. The plasma concentrations of cucurbitacin E were quantified up to 16h, while the plasma concentrations of cucurbitacin I remained below the limit of quantification. A population pharmacokinetic model was developed for cucurbitacin E using the NONMEM program, with adequate goodness of fit and predictive performance. The following pharmacokinetic parameters were obtained: release time of 0.45h, volume of distribution of 27.22L, clearance of 4.13L/h, and elimination half-life of 4.57h.

  6. Determination of roxithromycin in human plasma by HPLC with fluorescence and UV absorbance detection: application to a pharmacokinetic study.

    PubMed

    Główka, Franciszek K; Karaźniewicz-Łada, Marta

    2007-06-01

    A selective HPLC method with fluorescence detection for the determination of roxithromycin (ROX) in human plasma was described. After solid-phase extraction (SPE), ROX and erythromycin (internal standard, I.S.) were derivatized by treatment with 9-fluorenylmethyl chloroformate (FMOC-Cl). Optimal resolution of fluorescence derivatives of ROX and I.S. was obtained during one analytical run using reversed phase, C(18) column. The mobile phase was composed of potassium dihydrogenphosphate solution, pH 7.5 and acetonitrile. Fluorescence of the compounds was measured at the maximum excitation, 255 nm and emission, 313 nm, of ROX derivatives. Validation parameters of the method were also established. After SPE, differences in recoveries of ROX and erythromycin from human plasma were observed. The linear range of the standard curve of ROX in plasma was 0.5-10.0 mg/l. The validated method was successfully applied for pharmacokinetic studies of ROX after administration of a single tablet of ROX.

  7. 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.

  8. 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.

  9. Aerospace Applications of Non-Equilibrium Plasma

    NASA Technical Reports Server (NTRS)

    Blankson, Isaiah M.

    2016-01-01

    Nonequilibrium plasma/non-thermal plasma/cold plasmas are being used in a wide range of new applications in aeronautics, active flow control, heat transfer reduction, plasma-assisted ignition and combustion, noise suppression, and power generation. Industrial applications may be found in pollution control, materials surface treatment, and water purification. In order for these plasma processes to become practical, efficient means of ionization are necessary. A primary challenge for these applications is to create a desired non-equilibrium plasma in air by preventing the discharge from transitioning into an arc. Of particular interest is the impact on simulations and experimental data with and without detailed consideration of non-equilibrium effects, and the consequences of neglecting non-equilibrium. This presentation will provide an assessment of the presence and influence of non-equilibrium phenomena for various aerospace needs and applications. Specific examples to be considered will include the forward energy deposition of laser-induced non-equilibrium plasmoids for sonic boom mitigation, weakly ionized flows obtained from pulsed nanosecond discharges for an annular Hall type MHD generator duct for turbojet energy bypass, and fundamental mechanisms affecting the design and operation of novel plasma-assisted reactive systems in dielectric liquids (water purification, in-pipe modification of fuels, etc.).

  10. 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

  11. 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

  12. Beam Plasma Turbulence Study.

    DTIC Science & Technology

    1983-05-01

    Ney, and J . F. Karczewski, Spae Sci. Instrum ., 4, 143 (1978). -- ’.. ...... .. " ’- -’ ... -,,, ,i, ,, - . --. : s v.-’ Z XW , - .. . Ř ’ - ’ " p...interactions with the able plasma theorists, Dr. J . R. Jasperse at the Air Force Geophysics Laboratory, Drs. B. Basu and J . Retterer of the Space Data Analysis...Drs. J . D. Winningham and J . Burch at the Southwest Research Institute, Dr. D. Klumpar of the University of Texas at Dallas, Dr. P. Kintner of the

  13. Quantification of Lumefantrine in Human Plasma Using LC-MS/MS and Its Application to a Bioequivalence Study.

    PubMed

    Pingale, Satish G; Mangaonkar, Kiran V

    2013-01-01

    An analytical method based on protein precipitation has been developed and validated for analysis of lumefantrine in human plasma. Artesunate was used as an internal standard for lumefantrine. Inertsil ODS column provided chromatographic separation of analytes followed by detection with mass spectrometry. The method involves simple isocratic chromatographic condition and mass spectrometric detection in the positive ionization mode using an API-3000 system. The total run time was 2.5 minutes. The proposed method has been validated with linear range of 200-20000 ng/mL for lumefantrine. The intrarun and interrun precision values are within 6.66% and 5.56%, respectively, for lumefantrine at the lower limit of quantification level. The overall recovery for lumefantrine and artesunate was 93.16% and 91.05%, respectively. This validated method was used successfully for analysis of plasma samples from a bioequivalence study.

  14. HPLC analysis of plasma 9-methoxycanthin-6-one from Eurycoma longifolia and its application in a bioavailability/pharmacokinetic study.

    PubMed

    Tan, Saadiah; Yuen, Kah-Hay; Chan, Kit-Lam

    2002-04-01

    A new and simple HPLC method using fluorescence detection was developed to determine 9-methoxycanthin-6-one, an active compound of Eurycoma longifolia Jack in rat and human plasma. The method entailed direct injection of plasma sample after deproteinization using acetonitrile. The mobile phase comprised acetonitrile and distilled water (55 : 45, v/v). Analysis was run at a flow rate of 1.0 ml/min with the detector operating at an excitation wavelength of 371 nm and emission wavelength of 504 nm. The method was specific and sensitive with a detection limit of 0.6 ng/ml and a quantification limit of approximately 1.6 ng/ml. The method was applied in a pilot pharmacokinetic/bioavailability study of the compound in rats. Less than 1 % of the compound was found to be absorbed orally.

  15. Quantitative determination of pimozide in human plasma by liquid chromatography-mass spectrometry and its application in a bioequivalence study.

    PubMed

    Yan, Miao; Li, Huan-De; Chen, Ben-Mei; Liu, Xiao-Lei; Xu, Ping; Zhu, Yun-Gui

    2010-04-06

    A simple, sensitive and specific LC-ESI/MS method was developed for the determination of pimozide in human plasma. Pimozide and cinnarizine (internal standard) were isolated from plasma samples by liquid-liquid extraction. The chromatographic separation was accomplished on a Thermo Hypersil-HyPURITY C18 reversed-phase column (150mmx2.1mm, i.d., 5microm) with the mobile phase consisting of 5mM ammonium acetate (pH 3.5, adjusted with acetic acid)-methanol-acetonitrile (39:5:56, v/v/v). The lower limit of quantification was 0.02ng/mL, and the assay exhibited a linear range of 0.025-12.800ng/mL. The established method has been successfully applied to a bioequivalence study of 2 pimozide formulations in 32 healthy male Chinese volunteers.

  16. A rapid LC-MS/MS method for quantitation of eszopiclone in human plasma: application to a human pharmacokinetic study.

    PubMed

    Hotha, Kishore Kumar; Vijaya Bharathi, D; Jagadeesh, B; Ravindranath, L K; Jaya Veera, K N; Venkateswarulu, V

    2012-02-01

    A highly reproducible, specific and cost-effective LC-MS/MS method was developed for simultaneous estimation of eszopiclone (ESZ) with 50 μL of human plasma using paroxetine as an internal standard (IS). The API-4000 LC-MS/MS was operated under the multiple reaction-monitoring mode using the electrospray ionization technique. A simple liquid-liquid extraction process was used to extract ESZ and IS from human plasma. The total run time was 1.5 min and the elution of ESZ and IS occurred at 0.90 min; this was achieved with a mobile phase consisting of 0.1% formic acid-methanol (15:85, v/v) at a flow rate of 0.50 mL/min on a Discover C(18) (50 × 4.6 mm, 5 µm) column. The developed method was validated in human plasma with a lower limit of quantitation of 0.1 ng/mL for ESZ. A linear response function was established for the range of concentrations 0.10-120 ng/mL (r > 0.998) for ESZ. The intra- and inter-day precision values for ESZ were acceptable as per FDA guidelines. Eszopiclone was stable in the battery of stability studies, viz. bench-top, autosampler and freeze-thaw cycles. The developed assay method was applied to an oral bioequivalence study in humans.

  17. 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.

  18. Determination of salvianolic acid C in rat plasma using liquid chromatography-mass spectrometry and its application to pharmacokinetic study.

    PubMed

    Song, Junke; Zhang, Wen; Sun, Jialin; Zhang, Xue; Xu, Xiaona; Zhang, Li; Feng, Zhangying; Du, Guanhua

    2016-03-01

    A sensitive and reliable LC-ESI-MS method for the determination of salvianolic acid C in rat plasma has been developed and validated. Plasma samples were prepared by liquid-liquid extraction with ethyl acetate and separated on a Zorbax SB-C18 column (3.5 µm, 2.1 × 100 mm) at a flow rate of 0.3 mL/min using acetonitrile-water as mobile phase. The detection was carried out by a single quadrupole mass spectrometer with electrospray ionization source and selected ion monitoring mode. Linearity was obtained for salvianolic acid C ranging from 5 to 1000 ng/mL. The intra- and inter-day precisions (RSD, %) didn't exceed 9.96%, and the accuracy (RE, %) were all within ±3.64%. The average recoveries of the analyte and internal standard were >89.13%. Salvianolic acid C was proved to be stable during all sample storage, preparation and analytic procedures. The validated method was successfully applied to pharmacokinetic study after oral and intravenous administration of salvianolic acid C to rats. The absolute oral bioavailability of salvianolic acid C was 0.29 ± 0.05%. This method was further applied to simultaneous determination of salvianolic acid A, salvianolic acid B and salvianolic acid C in rat plasma and showed good practicability.

  19. 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.

  20. Novel applications of plasma actuators

    NASA Astrophysics Data System (ADS)

    Ozturk, Arzu Ceren

    The current study investigates the effectiveness of two different dielectric barrier discharge plasma actuator configurations, a 3-D annular geometry for use in micro thrusters and internal duct aerodynamics and a jet vectoring actuator that acts as a vortex generator and flow control device. The first configuration consists of a closed circumferential arrangement which yields a body force when a voltage difference is applied across the inner and outer electrodes separated by a dielectric. The primary flow is driven by this zero-net mass flux jet at the wall that then entrains fluid in the core of the duct. PIV experiments in both quiescent flow and freestream are conducted on tubes of different diameters while varying parameters such as the modulation frequency, duty cycle and tunnel speed. The values of the induced velocities increase with the forcing frequency and duty cycle although there is a peak value for the forcing frequency after which the velocity and thrust decrease for each thruster. The velocities and thrust increase as the inner diameter of the tubes are increased while the velocity profiles show a great difference with the (l/di) ratio; recirculation occurs after going below a critical value. Experiments in the wind tunnel illustrate that the jet exit characteristics significantly change upon actuation in freestream flow but the effect tends to diminish with increasing inner diameters and tunnel speeds. Using staged arrays of these thrusters result in higher velocities while operating at both in phase and out of phase. The jet vectoring configuration consists of a single embedded electrode separated from two exposed electrodes on either side by the dielectric. The embedded electrode is grounded while the exposed electrodes are driven with a high frequency high voltage input signal. PIV measurements of the actuator in a freestream show that vectoring the jet yields stronger vortices than a linear configuration and increasing the difference between

  1. 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.

  2. Simultaneous analysis of thiamphenicol and its prodrug thiamphenicol glycinate in human plasma and urine by high performance liquid chromatography: application to pharmacokinetic study.

    PubMed

    Chen, Xijing; Yang, Bing; Ni, Liang; Wang, Guangji

    2006-06-07

    A simple and sensitive method for simultaneous determination of the active compound, thiamphenicol (TAP) and its prodrug, thiamphenicol glycinate (TG) in human plasma and urine is described. The procedure involved extraction of TG and TAP with ethyl acetate (plasma) or 100-fold dilution with the mobile phase (urine) followed by determination by reversed-phase high performance liquid chromatography (HPLC) with UV detection at 224 nm. Separation of the compounds was achieved on a column packed with Hypersil ODS2. The mobile phase consisted of acetonitrile-water containing 0.003 M tetrabutyl ammonium bromide and 0.056 M ammonium acetate (87:13, v/v) with a flow rate of 1.0 ml/min. The chromatograms did not contain interfering peaks due to the suitable extraction procedure and chromatographic conditions. The calibration curves of TG and TAP were linear ranging from 0.78 to 100 microg/ml in plasma and in urine. The intra-day and inter-day relative standard deviations (S.D.) were less than 10%. The recoveries of TG and TAP in plasma and urine were above 80%. TG was not stable in plasma samples and after extraction at ambient temperature or in freeze-thaw cycles, and hence the samples for injection on HPLC column should be stored in refrigerator or under ice cooling prior to analysis, and the plasma samples should not experience the freeze-thaw cycle more than one time. Unlike TAP, TG could not be detected in most urine samples. Application of this method demonstrated that it was feasible for the clinical pharmacokinetic study.

  3. Determination of free and glucuronidated kaempferol in rat plasma by LC-MS/MS: application to pharmacokinetic study.

    PubMed

    Zhang, Wei-Dong; Wang, Xiao-Juan; Zhou, Si-Yuan; Gu, Yi; Wang, Rong; Zhang, Tao-Li; Gan, Hong-Quan

    2010-08-01

    Flavanoid kaempferol is mainly present as glucuronides and sulfates in rat plasma, and small amounts of the intact aglycone are also detected. In the this study, a rapid, specific and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry method (HPLC-MS/MS) was developed and validated for determination of kaempferol and its major metabolite glucuronidated kaempferol in rat plasma. A liquid-liquid extraction with acetic ether was involved for the extraction of kaempferol and internal standard. Analytes were separated on a C18 column (150 mm x 2.1 mm, 4.5 microm, Waters Corp.) with isocratic elution at a flow-rate of 0.3 ml min(-1). The mobile phase was consisted of 0.5% formic acid and acetonitrile (50:50, v/v). The Quattro Premier HPLC-MS/MS was operated under the multiple reaction-monitoring mode (MRM) using the electrospray ionization technique. The method was validated according to the FDA guidelines for validation of bioanalytical method. The validated method was successfully applied to the study of the pharmacokinetics in rats after oral administration of kaempferol with different doses.

  4. 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

  5. Determination of endogenous glycosaminoglycans derived disaccharides in human plasma by HPLC: validation and application in a clinical study.

    PubMed

    Upreti, Vijay V; Khurana, Manoj; Cox, Donna S; Eddington, Natalie D

    2006-02-02

    SB-424323 is a new, orally active anti-thrombotic agent presently in phase-II clinical development, with limited hemorrhagic risk and a unique mechanism of action involving the induction of glycosaminoglycans (GAGs) biosynthesis. The objective of the present study was to develop a simple and rapid high performance liquid chromatography (HPLC) method for determination of endogenous GAGs derived disaccharides in plasma samples from a phase-II clinical study of SB-424323. Sample preparation was a simple heat treatment of the diluted plasma followed by digestion of endogenous GAGs with chondroitinase ABC to yield unsaturated disaccharides, 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-D-galactose (DeltaDi-0S), 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-4-O-sulfo-D-galactose (DeltaDi-4S), and 2-acetamido-2-deoxy-3-O-(beta-D-gluco-4-enepyranosyluronic acid)-6-O-sulfo-D-galactose (DeltaDi-6S). These disaccharides were recovered and purified using centrifugal filtration through a filter with 3000 molecular weight cut-off along with externally added internal standard 2-acetamido-2-deoxy-3-O-(2-O-sulfo-beta-D-gluco-4-enepyranosyluronic acid)-D-galactose (DeltaDi-UA2S). A gradient reverse phase HPLC separation was developed on a Waters Symmetry C(18) column (4.6 mm x 150 mm, 5 microm) with a gradient mobile phase system consisting of 0.8 mM tetrabutylammonium hydrogen sulfate and 2mM sodium chloride and acetonitrile at a flow rate of 1.0 mL/min. The eluate was monitored with an ultraviolet detector set at 230 nm. Plasma standard curves were linear (r(2)> or =0.994) in the concentration range 1.0-20 microg/mL with a lower limit of quantification (LLOQ) of 1.0 microg/mL for each of the disaccharide. The mean measured quality control (QC) concentrations for the disaccharides deviated from the nominal concentrations in the range of -8.92 to 5.61% and -16.3 to 16.7%, for inter and intra-day, respectively. The inter and intra-day precision

  6. 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.

  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. Simple and Robust Analysis of Cefuroxime in Human Plasma by LC-MS/MS: Application to a Bioequivalence Study.

    PubMed

    Hu, Xingjiang; Huang, Mingzhu; Liu, Jian; Chen, Junchun; Shentu, Jianzhong

    2014-01-01

    A simple, robust LC-MS/MS assay for quantifying cefuroxime in human plasma was developed. Cefuroxime and tazobactam, as internal standard (IS), were extracted from human plasma by methanol to precipitate protein. Separation was achieved on a Zorbax SB-Aq (4.6 × 250 mm, 5  μ m) column under isocratic conditions. The calibration curve was linear in the concentration range of 0.0525-21.0  μ g/mL (r = 0.9998). The accuracy was higher than 90.92%, while the intra- and interday precision were less than 6.26%. The extraction procedure provides recovery ranged from 89.44% to 92.32%, for both analyte and IS. Finally, the method was successfully applied to a bioequivalence study of a single 500 mg dose of cefuroxime axetil in 22 healthy Chinese male subjects under fasting condition. Bioequivalence was determined by calculating 90% Cls for the ratios of C max, AUC0-t , and AUC0-∞ values for the test and reference products, using logarithmic transformed data. The 90% Cls for the ratios of C max (91.4%~104.2%), AUC0-t (97.4%~110.9%), and AUC0-∞ (97.6%~111.1%) values were within the predetermined range. It was concluded that the two formulations (test for capsule, reference for tablet) analyzed were bioequivalent in terms of rate and extent of absorption and the method met the principle of quick and easy clinical analysis.

  9. Simultaneous determination of irbesartan and hydrochlorothiazide in human plasma using HPLC coupled with tandem mass spectrometry: Application to bioequivalence studies.

    PubMed

    Tutunji, Lara F; Tutunji, Maha F; Alzoubi, Mamoun I; Khabbas, Manal H; Arida, Adi I

    2010-03-11

    A sensitive, specific and selective liquid chromatography/tandem mass spectrometric method has been developed and validated for the simultaneous determination of irbesartan and hydrochlorothiazide in human plasma. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard losartan were separated on a reverse phase C(18) column (50mmx4mm, 3microm) using water with 2.5% formic acid, methanol and acetonitrile (40:45:15, v/v/v (%)) as a mobile phase (flow rate of 0.70mL/min). Irbesartan and hydrochlorothiazide were ionized using ESI source in negative ion mode, prior to detection by multiple reaction monitoring (MRM) mode while monitoring at the following transitions: m/z 296-->269 and m/z 296-->205 for hydrochlorothiazide, 427-->175 for irbesartan. Linearity was demonstrated over the concentration range 0.06-6.00microg/mL for irbesartan and 1.00-112.00ng/mL for hydrochlorothiazide. The developed and validated method was successfully applied to a bioequivalence study of irbesartan (300mg) with hydrochlorothiazide (12.5mg) tablet in healthy volunteers (N=36).

  10. 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

    2008-11-04

    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.

  11. Characterization of a compact ECR plasma source and its applications to studies of helium ion damage to tungsten

    NASA Astrophysics Data System (ADS)

    Donovan, D.; Buchenauer, D.; Whaley, J.; Friddle, R.

    2016-02-01

    Exposure of tungsten to low energy (<100 eV) helium plasmas at temperatures between 900-1900 K in both laboratory experiments and tokamaks has been shown to cause severe nanoscale modification of the near surface resulting in the growth of tungsten tendrils. Tendril formation can lead to non-sputtered erosion and dust formation. Here we report on characterization of a compact electron cyclotron resonance (ECR) He plasma source with an ion flux of ˜2.5 × 1019 ions m-2 s-1, average fluence of 3 × 1024 ions m-2, and the surface morphology changes seen on the exposed tungsten surfaces. Exposures of polished tungsten disks at temperatures up to 1270 K have been performed and characterized using scanning electron microscopy and atomic force microscopy (AFM) scans. Bubbles and craters have been seen on the exposed tungsten surface growing to up to 150 nm in diameter. The ECR source has been tested for eventual use on a scanning tunneling microscopy experiment intended to study the early stages of surface morphology change due to He ion exposure.

  12. Sports medicine applications of platelet rich plasma.

    PubMed

    Mishra, Allan; Harmon, Kimberly; Woodall, James; Vieira, Amy

    2012-06-01

    Platelet rich plasma (PRP) is a powerful new biologic tool in sports medicine. PRP is a fraction of autologous whole blood containing and increased number of platelets and a wide variety of cytokines such as platelet derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and transforming growth factor beta-1 (TGF-B1), fibroblast growth factor (FGF), Insulin-like growth factor-1 (IGF-1) among many others. Worldwide interest in this biologic technology has recently risen sharply. Basic science and preclinical data support the use of PRP for a variety of sports related injuries and disorders. The published, peer reviewed, human data on PRP is limited. Although the scientific evaluation of clinical efficacy is in the early stages, elite and recreational athletes already use PRP in the treatment of sports related injuries. Many questions remain to be answered regarding the use of PRP including optimal formulation, including of leukocytes, dosage and rehabilitation protocols. In this review, a classification for platelet rich plasma is proposed and the in-vitro, preclinical and human investigations of PRP applications in sports medicine will be reviewed as well as a discussion of rehabilitation after a PRP procedure. The regulation of PRP by the World Anti-Doping Agency will also be discussed. PRP is a promising technology in sports medicine; however, it will require more vigorous study in order to better understand how to apply it most effectively.

  13. 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.

  14. Chlorpromazine quantification in human plasma by UPLC-electrospray ionization tandem mass spectrometry. Application to a comparative pharmacokinetic study.

    PubMed

    Borges, Ney Carter; Rezende, Vinicius Marcondes; Santana, Jose Marcos; Moreira, Ricardo Pereira; Moreira, Roberto Fernandes; Moreno, Patrícia; Borges, Diego Carter; Donato, José Luiz; Moreno, Ronilson Agnaldo

    2011-12-01

    In the present study a method to quantify chlorpromazine in human plasma using cyclobenzaprine as the internal standard (IS) is described. The analyte and the IS were extracted from human plasma by a liquid-liquid extraction with diethyl ether/dichloromethane (70/30, v/v) and analyzed by an ultra performance liquid chromatography (UPLC) coupled to an electrospray tandem triple quadrupole mass spectrometer in positive mode (UPLC-ES(+)-MS/MS). Chromatography was performed isocratically on an Aquity UPLC BEH C18 1.7 μm (50 mm × 2.1 mm i.d.) operating at 40°C. The mobile phase was a mixture of 65% water+1% formic acid and 35% of acetonitrile at a flow-rate of 0.5 mL/min. The lowest concentration quantified was 0.5 ng/mL and a linear calibration curve over the range 0.5-200 ng/mL was obtained, showing intra-assay precisions from 2.4 to 5.8%, and inter-assay precisions from 3.6 to 9.9%. The intra-assay accuracies ranged from 96.9 to 102.5%, while the inter-assay accuracies ranged from 94.1 to 100.3%. This analytical method was applied in a relative bioavailability study in order to compare a test chlorpromazine 100 mg simple dose formulation versus a reference in 57 volunteers of both sexes. The study was conducted in an open randomized two-period crossover design and with a fourteen days washout period. Plasma samples were obtained over a 144-h interval. Since the 90% CI for both C(max), AUC(last) and AUC(0-inf) were within the 80-125% interval proposed by the Food and Drug Administration and ANVISA, it was concluded that chlorpromazine 100 mg/dose was bioequivalent to the reference formulation, according to both the rate and extent of absorption.

  15. Quantitation of eleven active compounds of Aidi injection in rat plasma and its application to comparative pharmacokinetic study.

    PubMed

    Liu, Ran; Ma, Ran; Yu, Chunyu; Bi, Cathy Wenchuan; Yin, Yidi; Xu, Huarong; Shang, Hongwei; Bi, Kaishun; Li, Qing

    2016-07-15

    Aidi injection has been widely used for the treatment of colorectal cancer. The purpose of this study was to develop a sensitive and reliable method for simultaneous quantitation of 11 main active ingredients in Aidi injection and to compare the pharmacokinetics of these ingredients in normal and colorectal model cancer rats after tail vein injection. After being extracted by isopropanol-ethyl acetate (1:1, v/v), the plasma samples were analyzed with domperidone as internal standard. Then the analytes were separated on a Venusil MP C18 column with 0.15% formic acid and methanol. The detection was performed on HPLC-MS/MS system with turbo ion spray source in the positive ion and multiple reaction-monitoring mode. The assay was shown to be linear over the range of 0.004-4.0μgmL(-1) of syringin B, astragaloside II and isofraxidin; 0.01-10.0μgmL(-1) of calycosin-7-O-β-d-glucoside and astragaloside IV; 0.02-20.0μgmL(-1) of ginsenoside Rg1, Rb1, Rc and Rd; 0.04-40.0μgmL(-1) of syringin E; 0.06-60.0μgmL(-1) of ginsenoside Re. And the validated method has been successfully applied to compare pharmacokinetic profiles of the 11 ingredients in plasma. The pharmacokinetic results showed here were significant differences in pharmacokinetic parameters for eight analytes between two groups after injection, while no significant differences for astragaloside II, astragaloside IV and ginsenoside Rc. The present study has the advantages of short analysis time and easy sample preparation, which could more comprehensively reflect the quality of Aidi injection in single run. The method proposed could be of great use for pharmacokinetics, bioavailability or bioequivalence studies of Aidi injection in biological samples.

  16. 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.

  17. HPLC fluorescence method for the determination of nizatidine in human plasma and its application to pharmacokinetic study.

    PubMed

    Çakar, Mahmut B; Ulu, Sevgi T

    2014-06-01

    A sensitive high-performance liquid chromatographic (HPLC) method was developed for the determination of nizatidine in human plasma. Nizatidine was derivatized by 4-fluoro-7-nitrobenzofurazan (NBD-F). Chromatographic separation was performed on a Inertsil C18 column (150 mm × 4.6 mm, 5 µm) using isocratic elution by a mobile phase consisting of methanol/water (55:45) at a flow rate of 1.2 mL/min. Amlodipine was used as the internal standard (IS). Fluorescence detector was used operated at 461 nm (excitation) and 517 nm (emission), respectively. The calibration curve was linear over the range of 50-2000 ng/mL. This method was successfully applied to a pharmacokinetic study after oral administration of a dose (150 mg) of nizatidine.

  18. 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.

  19. Simultaneous determination of erlotinib and tamoxifen in rat plasma using UPLC-MS/MS: Application to pharmacokinetic interaction studies.

    PubMed

    Maher, Hadir M; Alzoman, Nourah Z; Shehata, Shereen M

    2016-08-15

    Tamoxifen (TAM) is a non-steroidal estrogen receptor antagonist that enhances erlotinib (ERL)-induced cytotoxicity in the treatment of NSCLC. ERL and TAM are metabolized by CYP3A4 enzymes. In addition, both drugs have the potential of altering the enzymatic activity through either inhibition (ERL) or induction (TAM). Thus it was expected that pharmacokinetics (PK) drug-drug interactions (DDIs) could be encountered following their co-administration. In this respect, a bioanalytical UPLC-MS/MS method has been developed and validated for the simultaneous determination of ERL and TAM in rat plasma samples, using ondansetron (OND) as an internal standard (IS). Plasma samples were prepared using mixed mode cationic solid phase extraction (SPE) STRATA™ -X-C 33μm cartridges with good extraction recovery of both drugs from rat plasma (Er% from -13.92 to -3.32). The drugs were separated on a Waters BEH™ C18 column with an isocratic elution using a mobile phase composed of a mixture of acetonitrile and water, each with 0.15% formic acid, in the ratio of 80: 20, v/v. Quantitation was carried out using the positive ionization mode with multiple reaction monitoring (MRM) at m/z 394.20>278.04 (ERL), m/z 372.25>72.01 (TAM), and m/z 294.18>170.16 (OND). The method was fully validated as per the FDA guidelines over the concentration range of 0.2-50ng/mL with very low lower limit of quantification (LLOQ) of 0.2ng/mL for both ERL and TAM. The intra- and inter-day assay precision (in terms of relative standard deviation, RSD) and accuracy (in terms of percentage relative error, % Er) were evaluated for both drugs and the calculated values evaluated at four different concentration levels were within the acceptable limits (<15%) for concentrations other than LLOQ and 20% for LLOQ. The method was successfully applied to the study of possible PK-DDI following the oral administration of ERL and TAM in a combination, compared to their single administration.

  20. 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...

  1. Compact plasma focus devices: Flexible laboratory sources for applications

    SciTech Connect

    Lebert, R.; Engel, A.; Bergmann, K.; Treichel, O.; Gavrilescu, C.; Neff, W.

    1997-05-05

    Small pinch plasma devices are intense sources of pulsed XUV-radiation. Because of their low costs and their compact sizes pinch plasmas seem well suited to supplement research activities based on synchrotrons. With correct optimisation, both continuous radiation and narrowband line radiation can be tailored for specific applications. For the special demand of optimising narrowband emission from these plasmas the scaling of K-shell line emission of intermediate atomic number pinch plasmas with respect to device parameters has been studied. Scaling laws, especially taking into account the transient behaviour of the pinch plasma, give design criteria. Investigations of the transition between column and micropinch mode offer predictable access to shorter wavelengths and smaller source sizes. Results on proximity x-ray lithography, imaging and contact x-ray microscopy, x-ray fluorescence (XFA) microscopy and photo-electron spectroscopy (XPS) were achieved.

  2. Determination of levetiracetam in human plasma by liquid chromatography/electrospray tandem mass spectrometry and its application to bioequivalence studies.

    PubMed

    Jain, Deepak S; Subbaiah, Gunta; Sanyal, Mallika; Pal, Usha; Shrivastav, Pranav S

    2006-01-01

    The first liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of levetiracetam, an antiepileptic drug, in human plasma is described. The plasma filtrate obtained after solid-phase extraction (SPE), using a polymer-based, hydrophilic-lipophilic balanced (HLB) cartridge, was submitted directly to a short column LC/MS/MS assay. There was no significant matrix effect on the analysis. For validation of the method, the recovery of the free analytes was compared to that from an optimized extraction method, and the analyte stability was examined under conditions mimicking sample storage, handling, and analytical procedures. The extraction procedure yielded extremely clean extracts with a recovery of 79.95% and 89.02% for levetiracetam and the internal standard (IS), respectively. The intra-assay and inter-assay precision for the samples at the lower limit of quantitation (LLOQ) were 6.33 and 6.82%, respectively. The calibration curves were linear for the dynamic range of 0.5 to 50 microg/mL with a correlation coefficient r >/= 0.9971. The intra-assay accuracy at LLOQ, LQC, MQC, and HQC levels ranged from 81.60 to 95.40, 93.00 to 103.47, 95.97 to 104.09, and 91.15 to 95.18%, respectively, while the inter-assay accuracy at LLOQ, LQC, MQC and HQC levels varied from 80.20 to 95.40, 88.53 to 107.53, 95.97 to 108.45, and 91.15 to 112.70%, respectively. The method is rugged and fast with a total instrumental run time of 2 min. The method was successfully applied for bioequivalence studies in human subject samples after oral administration of 1000 mg immediate release (IR) formulations.

  3. Systematic comparison of photoionised plasma codes with application to spectroscopic studies of AGN in X-rays

    NASA Astrophysics Data System (ADS)

    Mehdipour, M.; Kaastra, J. S.; Kallman, T.

    2016-12-01

    Atomic data and plasma models play a crucial role in the diagnosis and interpretation of astrophysical spectra, thus influencing our understanding of the Universe. In this investigation we present a systematic comparison of the leading photoionisation codes to determine how much their intrinsic differences impact X-ray spectroscopic studies of hot plasmas in photoionisation equilibrium. We carry out our computations using the Cloudy, SPEX, and XSTAR photoionisation codes, and compare their derived thermal and ionisation states for various ionising spectral energy distributions. We examine the resulting absorption-line spectra from these codes for the case of ionised outflows in active galactic nuclei. By comparing the ionic abundances as a function of ionisation parameter ξ, we find that on average there is about 30% deviation between the codes in ξ where ionic abundances peak. For H-like to B-like sequence ions alone, this deviation in ξ is smaller at about 10% on average. The comparison of the absorption-line spectra in the X-ray band shows that there is on average about 30% deviation between the codes in the optical depth of the lines produced at log ξ 1 to 2, reducing to about 20% deviation at log ξ 3. We also simulate spectra of the ionised outflows with the current and upcoming high-resolution X-ray spectrometers, on board XMM-Newton, Chandra, Hitomi, and Athena. From these simulations we obtain the deviation on the best-fit model parameters, arising from the use of different photoionisation codes, which is about 10 to 40%. We compare the modelling uncertainties with the observational uncertainties from the simulations. The results highlight the importance of continuous development and enhancement of photoionisation codes for the upcoming era of X-ray astronomy with Athena.

  4. Enantiospecific determination of arotinolol in rat plasma by LC-MS/MS: application to a stereoselective pharmacokinetic study.

    PubMed

    Qian, Zheyuan; Xu, Yanhai; Zheng, Leyi; Zhang, Jingbo; Hong, Zhanying; Shen, Xiaohang

    2015-01-01

    A highly sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and fully validated for quantification of arotinolol enantiomers in rat plasma using haloperidol as the internal standard. After solid phase extraction of 50.0 μL rat plasma in 96 well plate, a baseline resolution of arotinolol enantiomers was achieved on a CHIRALPAK AD-H column using the mobile phase of n-hexane and ethanol in 0.02% diethylamine (20:80, v/v) at a flow rate of 0.550 mL/min within 11.0 min. Acquisition of mass spectrometric data was performed on a triple-quadrupole mass spectrometer in multiple-reaction-monitoring (MRM) mode with an ESI source using the transition m/z 372.1 → 316.1 for (±)-arotinolol and m/z 376.1 → 165.1 for haloperidol. The calibration curves of both enantiomers were linear over the range of 1.00-200.0 ng/mL (r(2)>0.992) and the lower limit of quantification was 1.00 ng/mL. Intra- and inter-day precision ranged from 5.6% to 8.9% for R-(-)-arotinolol and 4.6-7.4% for S-(+)-arotinolol. Accuracy varied from 0.0% to 7.0% for R-(-)-arotinolol and 5.0-10.0% for S-(+)-arotinolol. For R-(-)-arotinolol, the recovery ranged from 87.2% to 99.2% and the matrix factor was 1.03-1.09; for S-(+)-arotinolol, the recovery ranged from 88.0% to 92.4% and the matrix factor was 0.84-0.95, both were not concentration dependent. The method was demonstrated with acceptable accuracy, precision and specificity for the determination of arotinolol enantiomers and has been successfully applied to a stereoselective pharmacokinetic study.

  5. 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.

  6. 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.

  7. CTR plasma engineering studies

    SciTech Connect

    Miley, G.H.

    1991-01-01

    Ash (e.g. thermalized helium from D-T) buildup in a tokamak can potentially prevent ignition and seriously degrade the fusion energy gain from driven system. This problem is most pronounced as the ratio of particle/energy confinement time increases towards the neoclassical limit. Yet much improved confinement of the fuel ions is desirable for a fusion reactor. The goals of the work described here were two fold: to study the effect of helium buildup on the energy balance for a tokamak, and consider methods of active control that might be employed to alleviate the problem. We examine ash buildup effect for both D-T and D-{sup 3}He systems. Most examples used apply to the ARIES 1 D-T reactor design and to the ARIES 3 D-{sup 3}He design since part of this was in support of these two designs. Then we report on brief studies of two potentially attractive control methods, namely controlled sawtooth and fishbone instabilities. The concept is that sawteeth or fishbones would be used on purpose periodically in order to flush'' out excess ash from the fusion core. Both methods are shown to feasible and attractive. More study is needed, however, since the phenomenona in which are physically complex. Still the pay off, namely, reduced ash buildup, is exceedingly important so that such studies desires strong attention.

  8. Spectrofluorometric determination of olanzapine and fluphenazine hydrochloride in pharmaceutical preparations and human plasma using eosin: application to stability studies.

    PubMed

    Belal, Fathalla; El-Brashy, Amina; El-Enany, Nahed; El-Bahay, Nihal

    2008-01-01

    A simple, rapid, and sensitive spectrofluorometric method has been developed for the determination of olanzapine (OLZ) and fluphenazine hydrochloride (FPZ HCI). The proposed method is based on the quantitative quenching effect of the studied drugs on the native fluorescence of eosin at pH 3.4 and 3.2 for OLZ and FPZ HCI, respectively. The fluorescence was measured at 547 nm after excitation at 323 nm. The fluorescence-concentration plots were rectilinear over the range of 0.05-1.0 and 0.10-1.0 microg/mL, with lower detection limits of 1.8 x 10(-3) and 1.2 x 10(-3) microg/mL, for OLZ and FPZ HCI, respectively. The proposed method was successfully applied to the analysis of commercial tablets and ampules containing the drugs, and the results were in good agreement with those obtained with reference methods. The proposed method was further applied to the determination of OLZ in spiked human plasma. The mean recovery was 98.62 +/- 0.24% (n = 4). The method was also used for stability studies of FPZ HCI upon oxidation with hydrogen peroxide, and the kinetics of the reaction were studied. A proposal for the reaction pathway was postulated.

  9. Simple and Sensitive High-Performance Liquid Chromatography (HPLC) Method with UV Detection for Mycophenolic Acid Assay in Human Plasma. Application to a Bioequivalence Study

    PubMed Central

    Danafar, Hossein; Hamidi, Mehrdad

    2015-01-01

    Purpose: A simple and available reversed-phase high performance liquid chromatography (HPLC) method with UV detection has been developed and validated for mycophenolic acid (MPA) assay in human plasma. Methods: MPA was extracted from plasma with protein precipitation method by acetonitrile: percholeric acid: methanol (75:5:20 v/v/v). The drug separation was achieved using a C8 analytical column and a mobile phase of 0.1M triethylammonium phosphate (pH=5.4)-acetonitril (65:35, v/v), with a flow rate of 1.5 ml/min. The detection wavelength was 304 nm. Limit of detection (LOD) of the method was determined as the lowest MPA concentration producing a signal-to-noise (S/N) ratio of about 3. Limit of quantitation (LOQ) was determined as the lowest MPA concentration capable of being quantitated with enough accuracy and precision. Results: The method showed significant linear response-concentration relationship throughout the MPA concentration range of 0.2-10 µg/ml. A typical linear regression equation of the method was: y = 8.5523 x + 0.094, with x and y representing MPA concentration (in µg/ml) and peak height respectively, and the regression coefficient (r) of 0.9816. The average within-run and between-run variations of 7.81 and 4.78 percent. The average drug recovery from plasma was 95.24 percent throughout the linear concentration range. The limits of detection (LOD) and quantitation (LOQ) of the method were 0.05 and 0.2 µg/ml, respectively. The practical applicability of the method was proven throughout a bioequivalence study. Conclusion: The results showed the acceptable degree of linearity, sensitivity, precision, accuracy and recovery for the method. The method was used successfully for quantitation of MPA in plasma samples of healthy volunteers throughout a bioequivalence study. PMID:26819930

  10. Reliable LC-MS/MS assay for the estimation of rilpivirine in human plasma: application to a bioequivalence study and incurred sample reanalysis.

    PubMed

    Gupta, Ajay; Guttikar, Swati; Patel, Yogesh; Shrivastav, Pranav S; Sanyal, Mallika

    2015-04-01

    A simple, precise, and rapid stable isotope dilution liquid chromatography-tandem mass spectrometry method has been developed and validated for the quantification of rilpivirine, a non-nucleoside reverse transcriptase inhibitor in human plasma. Rilpivirine and its deuterated analogue, rilpivirine-d6, used as an internal standard (IS) were quantitatively extracted by liquid-liquid extraction with methyl-tert-butyl ether and diethyl ether solvent mixture from 50 μL plasma. The chromatography was achieved on Gemini C18 (150 × 4.6 mm, 5 µm) analytical column in a run time of 2.2 min. The precursor → product ion transitions for rilpivirine (m/z 367.1 → 128.0) and IS (m/z 373.2 → 134.2) were monitored on a triple quadrupole mass spectrometer in the positive ionization mode. The linearity of the method was established in the concentration range of 0.5-200 ng/mL. The mean extraction recovery for rilpivirine (94.9%) and IS (99.9%) from spiked plasma samples was consistent and reproducible. The IS-normalized matrix factors for rilpivirine ranged from 0.98 to 1.02 across three quality controls. Bench top, freeze-thaw, wet extract, and long-term stability of rilpivirine was examined in spiked plasma samples. The application of the method was demonstrated by a bioequivalence study with 25 mg rilpivirine tablet formulation in 40 healthy subjects. The assay reproducibility was shown by reanalysis of 200 study samples and the % change in the concentration of repeat values from the original values was within ±15%.

  11. Validated LC-MS/MS assay for the quantitative determination of vardenafil in human plasma and its application to a pharmacokinetic study.

    PubMed

    Lake, Simon T; Altman, Phillip M; Vaisman, Jack; Addison, Russell S

    2010-08-01

    A sensitive high-performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) assay has been developed for the quantitative analysis of vardenafil in human plasma. Vardenafil and the internal standard, alprazolam, were extracted from 0.2 mL aliquots of alkalinized plasma by a single solvent extraction into hexane : dichloromethane. Reversed-phase chromatographic separation was affected by gradient elution with mobile phases consisting of 10 mM ammonium formate pH 7.0 (solvent A) and methanol (100%, solvent B), delivered at a flow rate of 0.4 mL/min. The analytes were detected by using an electrospray ion source on a 4000 QTrap triple quadrupole mass spectrometer operating in positive ionization mode. The mass transitions were m/z 489.3 --> 312.2 for vardenafil and m/z 309.2 --> 281.0 for alprazolam. The assay was linear over the concentration range of 0.2-100 ng/mL, with correlation coefficients > or = 0.995. The intra- and inter-day precision was less than 5.4% in terms of relative standard deviation and the accuracy was within 12.7% in terms of relative error. The lower limit of quantitation was set at 0.2 ng/mL. The high sensitivity and acceptable performance of the assay allowed its application to the analysis of plasma samples obtained following the oral administration of vardenafil to healthy male volunteers in a pharmacokinetic study.

  12. Near-infrared spectroscopy for burning plasma diagnostic applications.

    PubMed

    Soukhanovskii, V A

    2008-10-01

    Ultraviolet and visible (UV-VIS, 200-750 nm) atomic spectroscopy of neutral and ionized fuel species (H, D, T, and Li) and impurities (e.g., He, Be, C, and W) is a key element of plasma control and diagnosis on International Thermonuclear Experimental Reactor and future magnetically confined burning plasma experiments (BPXs). Spectroscopic diagnostic implementation and performance issues that arise in the BPX harsh nuclear environment in the UV-VIS range, e.g., degradation of first mirror reflectivity under charge-exchange atom bombardment (erosion) and impurity deposition, permanent and dynamic loss of window, and optical fiber transmission under intense neutron and gamma-ray fluxes, are either absent or not as severe in the near-infrared (NIR, 750-2000 nm) range. An initial survey of NIR diagnostic applications has been undertaken on the National Spherical Torus Experiment. It is demonstrated that NIR spectroscopy can be used for machine protection and plasma control applications, as well as contribute to plasma performance evaluation and physics studies. Emission intensity estimates demonstrate that NIR measurements are possible in the BPX plasma operating parameter range. Complications in the NIR range due to the parasitic background emissions are expected to occur at very high plasma densities, low impurity densities, and at high plasma-facing component temperatures.

  13. Novel application of plasma treatment for pharmaceutical and biomedical engineering.

    PubMed

    Kuzuya, Masayuki; Sasai, Yasushi; Kondo, Shin-Ichi; Yamauchi, Yukinori

    2009-06-01

    The nature of plasma-induced surface radicals formed on a variety of organic polymers has been studied by electron spin resonance (ESR), making it possible to provide a sound basis for future experimental design of polymer surface processing using plasma treatment. On the basis of the findings from such studies, several novel bio-applications in the field of drug- and biomedical- engineering have been developed. Applications for drug engineering include the preparation of reservoir-type drug delivery system (DDS) of sustained- and delayed-release, and floating drug delivery system (FDDS) possessing gastric retention capabilities, followed by preparation of "Patient-Tailored DDS". Furthermore, the preparation of composite powders applicable to matrix-type DDS was developed by making a mechanical application to the surface radical-containing polymer powders with drug powders. In applications for biomedical engineering, the novel method to introduce the durable surface hydrophilicity and lubricity on hydrophobic biomedical polymers was developed by plasma-assisted immobilization of carboxyl group-containing polymer on the polymer substrate. The surfaces thus prepared were further used for the covalent immobilization of oligo-nucleotides (DNA) onto the polymer surfaces applicable to constructing DNA diagnosis system, and also plasma-assisted preparation of functionalized chemo-embolic agent of vinyl alcohol-sodium acrylate copolymer (PVA- PAANa).

  14. UPLC-MS/MS determination of phentolamine in human plasma and its application to a pharmacokinetic study.

    PubMed

    Kan, X; Zheng, S-L; Zhou, C-Y

    2014-11-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine phentolamine in human plasma. Sample preparation was accomplished through a simple liquid-liquid extraction with ethyl acetate. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column using an isocratic mobile phase system composed of acetonitrile and 1% formic acid in water (33:67, v/v) at a flow rate of 0.45 mL/min. Mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 282.1 → 212.0 and m/z 237.1 → 194.2 were used to quantify for phentolamine and carbamazepine (internal standard, IS), respectively. The linearity of this method was found to be within the concentration range of 0.5-100.0 ng/mL with a lower limit of quantification of 0.5 ng/mL. Only 1.0 min was needed for an analytical run. This fully validated method was successfully applied to the pharmacokinetic study after oral administration of 60 mg phentolamine to 20 Chinese healthy male volunteers.

  15. Determination of Sertraline in Human Plasma by UPLC-MS/MS and its Application to a Pharmacokinetic Study.

    PubMed

    Yue, Xiao-Hong; Wang, Zhen; Tian, Dong-Dong; Zhang, Jian-Wei; Zhu, Kang; Ye, Qiang

    2016-02-01

    A sensitive and rapid ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS) method was developed to determine sertraline in human plasma. Sample preparation was accomplished through a simple liquid-liquid extraction with ethyl acetate. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column using a gradient mobile phase system composed of acetonitrile and 1% formic acid in water at a flow rate of 0.40 mL/min. Mass spectrometric analysis was performed using a XEVO TQD mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The multiple reaction monitoring transitions of m/z 306.3 → 275.2 and 326.2 → 291.1 were used to quantify for sertraline and midazolam (internal standard), respectively. The linearity of this method was found to be within the concentration range of 1.0-100.0 ng/mL with a lower limit of quantification of 1.0 ng/mL. Only 2.0 min was needed for an analytical run. This fully validated method was successfully applied to the pharmacokinetic study after an oral administration of 100 mg sertraline to 20 Chinese healthy male volunteers.

  16. LC-MS/MS method for determination of megestrol in human plasma and its application in bioequivalence study.

    PubMed

    Li, Fan; Zou, Xiao-juan; Zheng, Heng; Xiang, Yi

    2013-12-01

    A rapid and highly selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of megestrol in human plasma was described using medrysone as internal standard (IS). Blood samples were collected from 20 healthy volunteers after oral administration of 160 mg megestrol acetate dispersible tablets. The analytes were extracted by liquid-liquid extraction procedure and separated on a hanbon lichrospher column with the mobile phase of methanol and water containing 0.1% formic acid and 20 mmol/L ammonium acetate (5:1, v/v). Positive ion electrospray ionization with multiple reaction-monitoring mode (MRM) was employed by monitoring the transitions m/z 385.5-325.4 and m/z 387.5-327.4 for megestrol and medrysone, respectively. Under the isocratic separation conditions, the chromatographic run time was approximately 2.54 min for megestrol and 2.59 min for medrysone. The calibration curve range was from 0.5 to 200.0 ng/mL. The inter-batch and intra-batch precision and accuracy were less than 5.2% relative standard deviation (RSD) and 6.4% relative error (RE). The proposed method was successfully applied in the bioequivalence study of megestrol acetate dispersible tablets.

  17. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

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

    2016-09-08

    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.

  18. Studies on the preparation and plasma spherodization of yttrium aluminosilicate glass microspheres for their potential application in liver brachytherapy

    NASA Astrophysics Data System (ADS)

    Sreekumar, K. P.; Saxena, S. K.; Kumar, Yogendra; Thiyagarajan, T. K.; Dash, Ashutosh; Ananthapadmanabhan, P. V.; Venkatesh, Meera

    2010-02-01

    Plasma spheroidization exploits the high temperature and high enthalpy available in the thermal plasma jet to melt irregularly shaped powder particles and quench them to get dense spherical particles. Plasma spheroidization is a versatile process and can be applied to metals, ceramics, alloys and composites to obtain fine spherical powders. Radioactive microspheres incorporated with high energetic beta emitting radioisotopes have been reported to be useful in the palliative treatment of liver cancer. These powders are to be prepared in closer range of near spherical morphology in the size range 20-35 microns. Inactive glass samples were prepared by heating the pre-calculated amount of glass forming ingredients in a recrystallized alumina crucible. The glass was formed by keeping the glass forming ingredients at 1700°C for a period of three hours to form a homogeneous melt. After cooling, the glass was recovered from the crucible by crushing and was subsequently powdered mechanically with the help of mortar and pestle. This powder was used as the feed stock for plasma spheroidization using an indigenously developed 40 kW plasma spray system. Experiments were carried out at various operating parameters. The operating parameters were optimised to get spheroidised particles. The powder was sieved to get the required size range before irradiation.

  19. Plasma Studies in Ion Diodes.

    DTIC Science & Technology

    1984-09-01

    high power pulse, with a typical rise time of 10 ns, to a pulsed high current vacuum diode (also variously referred to as an explosive emission , field...instantaneous event. One motivation for such studies was the developement of high voltage devices, such as x - ray tubes. for which vacuum breakdown was...Sources of high current , high voltage particle beams rely on the intermedi- ate phase of vacuum breakdown, between initial plasma formation and gap clo

  20. Clinical application of plasma thermograms. Utility, practical approaches and considerations.

    PubMed

    Garbett, Nichola C; Mekmaysy, Chongkham S; DeLeeuw, Lynn; Chaires, Jonathan B

    2015-04-01

    Differential scanning calorimetry (DSC) studies of blood plasma are part of an emerging area of the clinical application of DSC to biofluid analysis. DSC analysis of plasma from healthy individuals and patients with various diseases has revealed changes in the thermal profiles of the major plasma proteins associated with the clinical status of the patient. The sensitivity of DSC to the concentration of proteins, their interactions with other proteins or ligands, or their covalent modification underlies the potential utility of DSC analysis. A growing body of literature has demonstrated the versatility and performance of clinical DSC analysis across a range of biofluids and in a number of disease settings. The principles, practice and challenges of DSC analysis of plasma are described in this article.

  1. Development and validation of sensitive LC/MS/MS method for quantitative bioanalysis of levonorgestrel in rat plasma and application to pharmacokinetics study.

    PubMed

    Ananthula, Suryatheja; Janagam, Dileep R; Jamalapuram, Seshulatha; Johnson, James R; Mandrell, Timothy D; Lowe, Tao L

    2015-10-15

    Rapid, sensitive, selective and accurate LC/MS/MS method was developed for quantitative determination of levonorgestrel (LNG) in rat plasma and further validated for specificity, linearity, accuracy, precision, sensitivity, matrix effect, recovery efficiency and stability. Liquid-liquid extraction procedure using hexane:ethyl acetate mixture at 80:20 v:v ratio was employed to efficiently extract LNG from rat plasma. Reversed phase Luna column C18(2) (50×2.0mm i.d., 3μM) installed on a AB SCIEX Triple Quad™ 4500 LC/MS/MS system was used to perform chromatographic separation. LNG was identified within 2min with high specificity. Linear calibration curve was drawn within 0.5-50ng·mL(-1) concentration range. The developed method was validated for intra-day and inter-day accuracy and precision whose values fell in the acceptable limits. Matrix effect was found to be minimal. Recovery efficiency at three quality control (QC) concentrations 0.5 (low), 5 (medium) and 50 (high) ng·mL(-1) was found to be >90%. Stability of LNG at various stages of experiment including storage, extraction and analysis was evaluated using QC samples, and the results showed that LNG was stable at all the conditions. This validated method was successfully used to study the pharmacokinetics of LNG in rats after SubQ injection, providing its applicability in relevant preclinical studies.

  2. 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

    2016-09-05

    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.

  3. 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.

  4. Some studies of whistler mode propagation in the magnetospheric plasma

    NASA Astrophysics Data System (ADS)

    Sazhin, S. S.

    1981-02-01

    Limits in the application of a cold plasma model to whistler propagation in the magnetospheric plasma are studied. It is pointed out that finite anisotropy of magnetospheric plasma can compensate for the influence of finite temperature on whistler propagation so that the cold plasma model can be applied. An approximate formula is obtained for whistler refractive index for the case of oblique propagation in a hot anisotropic plasma with a loss cone. This formula is applied to the problem of whistler energy focusing along the magnetic field in the homogeneous plasma and whistler mode propagation in magnetospheric ducts. The possibility of whistler trapping in ducts formed by temperature gradients in the magnetospheric plasma is pointed out.

  5. Applications of the concept of generalized vorticity to space plasmas

    NASA Technical Reports Server (NTRS)

    Banks, P. M.; Edwards, W. F.; Rasmussen, C.; Thompson, R. C.

    1981-01-01

    A reformulation of the momentum equation for electrons or ions in a collisionless plasma leads to an equation which describes the behavior of the plasma in terms of a generalized vorticity. This vorticity is both divergence-free and conserved along plasma flow streamlines. When the plasma has zero vorticity, a special relation is established which appears to have application to small scale magnetic features within both conventional space plasmas and superconductors.

  6. 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.

  7. 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.

  8. 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.

  9. Fundamental studies of fusion plasmas. Final report

    SciTech Connect

    Aamodt, R.E.

    1998-01-30

    Lodestar has carried out a vigorous research program in the areas of rf, edge plasma and divertor physics, with emphasis largely geared towards improving the understanding and performance of ion-cyclotron heating and current drive (ICRF) systems. Additionally, a research program in the field of edge plasma and divertor modeling was initiated. Theoretical work on high power rf sheath formation for multi-strap rf arrays was developed and benchmarked against recent experimental data from the new JET A2 antennas. Sophisticated modeling tools were employed to understand the sheath formation taking into account realistic three-dimensional antenna geometry. A novel physics explanation of an observed anomaly in the low power loading of antennas was applied to qualitatively interpret data on DIII-D in terms of rf sheaths, and potential applications of the idea to develop a near-field sheath diagnostic were explored. Other rf-wave related topics were also investigated. Full wave ICRF modeling studies were carried out in support of ongoing and planned tokamaks experiments, including the investigation of low frequency plasma heating and current drive regimes for IGNITOR. In a cross-disciplinary study involving both MHD and ICRF physics, ponderomotive feedback stabilization by rf was investigated as a potential means of controlling external kink mode disruptions. In another study, the instability of the ion hybrid wave (IHW) in the presence of fusion alpha particles was studied. In the field of edge plasma and divertor modeling studies, Lodestar began the development of a theory of generalized ballooning and sheath instabilities in the scrape off layer (SOL) of divertor tokamaks. A detailed summary of the technical progress in these areas during the contract period is included, as well as where references to published work can be found. A separate listing of publications, meeting abstracts, and other presentations is also given at the end of this final report.

  10. 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...

  11. RF generated atmospheric pressure plasmas and applications

    NASA Astrophysics Data System (ADS)

    Park, Jaeyoung; Herrmann, Hans W.; Henins, Ivars; Gautier, Donald C.

    2001-10-01

    RF generated atmospheric pressure plasma sources have been developed for various materials applications. They operate with rf power and produce a α-mode capacitive discharge that is stable, steady-state, non-thermal, and volumetric. The plasma parameters of this source have been measured: electron densities of 10^11 cm-3 and electron temperatures of 2 eV by using neutral bremsstrahlung emission. Localized electron heating near the sheath boundary has been observed and is related to the discharge stability and α to γ mode (or arcing) transition using 1D fluid model. The discharge stability improves with increase in rf frequency. The electrode surface property such as the secondary electron emission coefficient also plays a significant role in determining α to γ mode transition. For example, a stable α-mode air discharge is produced using 100 MHz rf power with the use of a boron nitride cover on one of the electrodes. In comparison, an air discharge becomes unstable at a lower rf frequency (e.g. 13.56 MHz) or with an alumina cover. Similar results were obtained with various feedgas such as steam, CO_2, and hydrocarbon containing gases. Further characterization of this high frequency source is under progress. For its applications, we have successfully demonstrated the effective neutralization of actual chemical warfare agents such as VX, GD and HD. In addition, significant progresses have been made in the area of etching of organic and metal film etching, and production of novel materials.

  12. 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.

  13. A validated LC-MS/MS method for quantitative analysis of curcumin in mouse plasma and brain tissue and its application in pharmacokinetic and brain distribution studies.

    PubMed

    Ramalingam, Prakash; Ko, Young Tag

    2014-10-15

    Curcumin is a well-known multitherapeutic agent widely employed in neurodegenerative disorders and cancer. A selective, fast, and sensitive method employing liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated for the simultaneous determination of curcumin in mouse plasma and brain tissue, by using salbutamol as an internal standard. Triple quadrupole mass detection with multiple reaction monitoring (MRM) mode was used to monitor the ion transitions, m/z of 369>285 for curcumin, and m/z of 240>148 for salbutamol. The method was validated for recovery, accuracy, precision, linearity, and applicability. The lower limits of quantification (LLOQ) in both matrices were 2.5ng/mL. The inter-day and intra-day precisions and accuracy values were within the Food and Drug Administration (FDA) acceptance criteria, for both matrixes. The method was successfully applied in pharmacokinetics and brain distribution studies of curcumin after intravenous administration of free curcumin and curcumin-loaded solid lipid nanoparticles to mice. Furthermore, the application of this method along with serial blood sampling in mice has led to significant reduction in animal use and dosage and drastic improvement in speed, throughput, and quality of pharmacokinetic parameters.

  14. 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.

  15. The study of helicon plasma source.

    PubMed

    Miao, Ting-Ting; Zhao, Hong-Wei; Liu, Zhan-Wen; Shang, Yong; Sun, Liang-Ting; Zhang, Xue-Zhen; Zhao, Huan-Yu

    2010-02-01

    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(13) cm(-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(-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.

  16. Plasma Detachment Study in VASIMR

    NASA Astrophysics Data System (ADS)

    Ilin, A. V.; Díaz, F. R. Chang; Squire, J. P.; Breizman, B. N.; Novakovski, S. V.; Sagdeev, R. Z.

    2000-10-01

    We present kinetic and MHD simulations of plasma detachment in the exhaust of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). The detachment is associated with a transition from subalfvenic to superalfvenic plasma flow in the magnetic nozzle. As a result, the kinetic energy of the outgoing plasma flow is greater than the magnetic field energy in the exhaust area, so that the plasma is no longer confined by the magnetic field. We model the outgoing plasma flow under the assumptions that the plasma is collisionless and has a constant electron temperature. Particle simulations show that the ion motion may become nonadiabatic in the exhaust area as the magnetic field decreases downstream. This effect should facilitate the detachment.

  17. 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.

  18. An HPLC-MS method for the quantification of new acetylcholinesterase inhibitor PC 48 (7-MEOTA-donepezil like compound) in rat plasma: Application to a pharmacokinetic study.

    PubMed

    Mzik, Martin; Korabecny, Jan; Nepovimova, Eugenie; Voříšek, Viktor; Palička, Vladimir; Kuca, Kamil; Zdarova Karasova, Jana

    2016-05-01

    A simple, rapid and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated for the quantitative determination in rat plasma of a new candidate for AD treatment, namely PC 48 (a 7-MEOTA-donepezil like compound) in rat plasma. Sample preparation involved pH adjustment with sodium hydroxide followed by solvent extraction with ethyl acetate:dichloromethane (80:20, v/v). The chromatographic separation was achieved on an Ascentis Express RP-Amide column (75 mm × 2.1mm, 2.7 μm) with a gradient mobile phase consisting of 0.05 M aqueous formic acid and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry on an LTQ XL system using the MS/MS CID (collision-induced dissociation) mode. The method was linear in the range 0.1-1000 ng/ml (r(2)=0.999) with a lower limit of quantitation of 0.1 ng/mL. Extraction recovery was in the range 63.5-72.1% for PC 48 and 70.5% for reserpine (internal standard, IS). Intra- and inter-day precisions measured as relative standard deviation were below 10.8% and accuracy was from -7.2% to 7.4%. The method was successfully applied to a pharmacokinetic study involving intramuscular application of 3.86 mg/kg PC 48 to rats for the first time. Pharmacokinetic parameters for PC 48 include Cmax 39.09 ± 4.45 ng/mL,Tmax 5.00 ± 3.08 min, AUC0-t 23374 ± 4045 min ng/mL and t1/2 1065 ± 246 min.

  19. 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

  20. Study of Cryogenic Complex Plasma

    DTIC Science & Technology

    2008-10-27

    Australia and the other in the Summer College on Plasma Physics at Abdus Salam International Centre for Theoretical Physics in Italy. Analytical...Structure Formation of Coulomb Clusters, Summer College on Plasma Physics, Abdus Salam International Centre for Theoretical Physics (ASICTP). August

  1. 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.

  2. 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.

  3. Plasma medicine—current state of research and medical application

    NASA Astrophysics Data System (ADS)

    Weltmann, K.-D.; von Woedtke, Th

    2017-01-01

    Plasma medicine means the direct application of cold atmospheric plasma (CAP) on or in the human body for therapeutic purposes. Further, the field interacts strongly with results gained for biological decontamination. Experimental research as well as first practical application is realized using two basic principles of CAP sources: dielectric barrier discharges (DBD) and atmospheric pressure plasma jets (APPJ). Originating from the fundamental insights that the biological effects of CAP are most probably caused by changes of the liquid environment of cells, and are dominated by reactive oxygen and nitrogen species (ROS, RNS), basic mechanisms of biological plasma activity are identified. It was demonstrated that there is no increased risk of cold plasma application and, above all, there are no indications for genotoxic effects. The most important biological effects of cold atmospheric pressure plasma were identified: (1) inactivation of a broad spectrum of microorganisms including multidrug resistant ones; (2) stimulation of cell proliferation and tissue regeneration with lower plasma treatment intensity (treatment time); (3) inactivation of cells by initialization of programmed cell death (apoptosis) with higher plasma treatment intensity (treatment time). In recent years, the main focus of clinical applications was in the field of wound healing and treatment of infective skin diseases. First CAP sources are CE-certified as medical devices now which is the main precondition to start the introduction of plasma medicine into clinical reality. Plasma application in dentistry and, above all, CAP use for cancer treatment are becoming more and more important research fields in plasma medicine. A further in-depth knowledge of control and adaptation of plasma parameters and plasma geometries is needed to obtain suitable and reliable plasma sources for the different therapeutic indications and to open up new fields of medical application.

  4. Plasma chemistry study of PLAD processes

    SciTech Connect

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

    2012-11-06

    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 B{sub 2}H{sub 6}, BF{sub 3}, AsH{sub 3}, and PH{sub 3}, and two non-dopant plasmas including CH{sub 4} and GeH{sub 4} are studied and demonstrated.

  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. 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

  7. 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).

  8. The Study on Inhibition of Planktonic Bacterial Growth by Non-Thermal Atmospheric Pressure Plasma Jet Treated Surfaces for Dental Application.

    PubMed

    Yoo, Eun-Mi; Uhm, Soo-Hyuk; Kwon, Jae-Sung; Choi, Hye-Sook; Choi, Eun Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2015-02-01

    Investigation of the effects by non-thermal atmospheric pressure plasma jet (NTAPPJ) treatment on the titanium dental implant surfaces for the inhibition of two common pathogens related with dental infections, Streptococcus mutans and Staphylococcus aureus, was carried out in this study. The commercially pure titanium was used as specimen, which were irradiated by NTAPPJ for 30, 60 and 120 seconds. Specimen without being treated with NTAPPJ was assigned as the control group. The X-ray photoelectron spectroscope and surface contact angle goniometer were used to analyze the effects of NTAPPJ treatment on surface chemistry and hydrophilicity of the specimen. The effects of the NTAPPJ treatment on surfaces, in terms of bacterial attachment, growth, morphology and structural changes were evaluated by the number of colony forming units (CFU) and scanning electron microscopy (SEM) observations. The results showed that there was a reduction of CFUs and the significant change in morphology of bacteria as they were cultured on the titanium surfaces treated with NTAPPJ. These results were related to surface chemical changes and hydrophilicity changes by NTAPPJ. The NTAPPJ treatment is very effective on the dental implant titanium surface treatment that resulted in the inhibition of bacteria and has a great potential to be a promising technique in various clinical dental applications.

  9. A simple and sensitive HPLC method for analysis of imipramine in human plasma with UV detection and liquid-liquid extraction: Application in bioequivalence studies

    PubMed Central

    Rezazadeh, Mahboubeh; Emami, Jaber

    2016-01-01

    High-performance liquid chromatography (HPLC) methods employing ultraviolet (UV) detector are not sufficiently sensitive to measure the low plasma concentrations following single oral dose of imipramine. Therefore, in the present study a simple, rapid and yet sensitive HPLC method with UV detection was developed and validated for quantitation of imipramine in human plasma samples. An efficient liquid-liquid extraction (LLE) of imipramine from plasma with the mixture of hexane/isoamyl alcohol (98:2) and back extraction of the drug in acidic medium concomitant with evaporation of organic phase allowed the use of UV detector to conveniently measure plasma levels of this compound as low level as 3 ng/ml. Separation was achieved on a μ-Bondapak C18 HPLC column using sodium hydrogen phosphate solution (0.01 M)/acetonitrile (60/40 v/v) at pH 3.5 ± 0.1 at 1.5 ml/min. Trimipramine was used as the internal standard for analysis of plasma samples. The retention times for imipramine and trimipramine were 4.3 and 5.2 min, respectively. Calibration curve was linear in the range of 3-40 ng/ml using human plasma with the average extraction recovery of 85 ± 5%. Imipramine was found to be stable in plasma samples with no evidence of degradation during three freeze-thaw cycles and three months storage at -70°C. The current validated method was finally applied in bioequivalence studies of two different imipramine products according to a standard two-way crossover design with a two weeks washout period. PMID:27168757

  10. A simple and sensitive HPLC method for analysis of imipramine in human plasma with UV detection and liquid-liquid extraction: Application in bioequivalence studies.

    PubMed

    Rezazadeh, Mahboubeh; Emami, Jaber

    2016-01-01

    High-performance liquid chromatography (HPLC) methods employing ultraviolet (UV) detector are not sufficiently sensitive to measure the low plasma concentrations following single oral dose of imipramine. Therefore, in the present study a simple, rapid and yet sensitive HPLC method with UV detection was developed and validated for quantitation of imipramine in human plasma samples. An efficient liquid-liquid extraction (LLE) of imipramine from plasma with the mixture of hexane/isoamyl alcohol (98:2) and back extraction of the drug in acidic medium concomitant with evaporation of organic phase allowed the use of UV detector to conveniently measure plasma levels of this compound as low level as 3 ng/ml. Separation was achieved on a μ-Bondapak C18 HPLC column using sodium hydrogen phosphate solution (0.01 M)/acetonitrile (60/40 v/v) at pH 3.5 ± 0.1 at 1.5 ml/min. Trimipramine was used as the internal standard for analysis of plasma samples. The retention times for imipramine and trimipramine were 4.3 and 5.2 min, respectively. Calibration curve was linear in the range of 3-40 ng/ml using human plasma with the average extraction recovery of 85 ± 5%. Imipramine was found to be stable in plasma samples with no evidence of degradation during three freeze-thaw cycles and three months storage at -70°C. The current validated method was finally applied in bioequivalence studies of two different imipramine products according to a standard two-way crossover design with a two weeks washout period.

  11. 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.

  12. Determination of flunarizine in plasma by a new high-performance liquid chromatography method. Application to a bioavailability study in the rat.

    PubMed

    Aparicio, X; Gras, J; Campos, A; Fernandez, E; Gelpí, E

    1988-01-01

    A reversed-phase high performance liquid chromatographic (HPLC) method is described for the study of the pharmacokinetics of flunarizine. The method involves selective liquid-solid extraction of flunarizine and meclizine (as internal standard) from samples of rat plasma. The optimization of the extraction and HPLC separation parameters are discussed. Recoveries were satisfactory and the relative standard deviation for replicate assays was below 10%. The sensitivity of the method would allow the detection of flunarizine in plasma at 13 ng ml(-1). Kinetic parameters for a bioequivalency study between flunarizine and a liquid formulation (oral drops) have been evaluated; the relative bioavailability was 88%.

  13. 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.

  14. Study of Photoemissive Dusty Plasma

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

    Gul, Banat; Aman-ur-Rehman

    2015-10-01

    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+, Br+, 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.

  16. 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.

  17. Applications of quantum cascade lasers in plasma diagnostics: a review

    NASA Astrophysics Data System (ADS)

    Röpcke, J.; Davies, P. B.; Lang, N.; Rousseau, A.; Welzel, S.

    2012-10-01

    Over the past few years mid-infrared absorption spectroscopy based on quantum cascade lasers operating over the region from 3 to 12 µm and called quantum cascade laser absorption spectroscopy or QCLAS has progressed considerably as a powerful diagnostic technique for in situ studies of the fundamental physics and chemistry of molecular plasmas. The increasing interest in processing plasmas containing hydrocarbons, fluorocarbons, nitrogen oxides and organo-silicon compounds has led to further applications of QCLAS because most of these compounds and their decomposition products are infrared active. QCLAS provides a means of determining the absolute concentrations of the ground states of stable and transient molecular species at time resolutions below a microsecond, which is of particular importance for the investigation of reaction kinetics and dynamics. Information about gas temperature and population densities can also be derived from QCLAS measurements. Since plasmas with molecular feed gases are used in many applications such as thin film deposition, semiconductor processing, surface activation and cleaning, and materials and waste treatment, this has stimulated the adaptation of QCLAS techniques to industrial requirements including the development of new diagnostic equipment. The recent availability of external cavity (EC) QCLs offers a further new option for multi-component detection. The aim of this paper is fourfold: (i) to briefly review spectroscopic issues arising from applying pulsed QCLs, (ii) to report on recent achievements in our understanding of molecular phenomena in plasmas and at surfaces, (iii) to describe the current status of industrial process monitoring in the mid-infrared and (iv) to discuss the potential of advanced instrumentation based on EC-QCLs for plasma diagnostics.

  18. 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

  19. LC-MS/MS determination of cinacalcet enantiomers in rat plasma on Chirobiotic V column in polar ionic mode: application to a pharmacokinetic study.

    PubMed

    Ramisetti, Nageswara Rao; Bompelli, Sravan

    2014-12-01

    A simple and selective polar ionic liquid chromatography-tandem mass spectrometric method for separation and determination of cinacalcet enantiomers in rat plasma was developed and validated. The chromatographic separation was accomplished on a Chirobiotic V column packed with vancomycin as a chiral stationary phase using 2.5 mm ammonium formate in 100% methanol as a mobile phase in an isocratic mode of elution at a flow rate of 1.0 mL/min. The analytes were extracted from rat plasma by precipitating the proteins with acetonitrile. The developed method exhibited a linear dynamic range over 0.5-500 ng/mL in rat plasma for both enantiomers. The method was successfully applied to study the pharmacokinetics after a single dose by oral administration of 10 mg/kg of cinacalcet enantiomers to healthy male Wistar rats.

  20. Potential applications of an electron cyclotron resonance multicusp plasma source

    SciTech Connect

    Tsai, C.C.; Berry, L.A.; Gorbatkin, S.M.; Haselton, H.H.; Roberto, J.B.; Stirling, W.L.

    1989-01-01

    An electron cyclotron resonance (ECR) multicusp plasmatron has been developed by feeding a multicusp bucket arc chamber with a compact ECR plasma source. This novel source produced large (about 25-cm-diam), uniform (to within {plus minus}10%), dense (>10{sup 11}-cm{sup -3}) plasmas of argon, helium, hydrogen, and oxygen. It has been operated to produce an oxygen plasma for etching 12.7-cm (5-in.) positive photoresist-coated silicon wafers with uniformity within {plus minus}8%. Results and potential applications of this new ECR plasma source for plasma processing of thin films are discussed. 21 refs., 10 figs.

  1. 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.

  2. Application of Plasma Technology in the Life Sciences

    NASA Astrophysics Data System (ADS)

    Short, Robert

    2002-10-01

    This paper explores the versatility of plasma polymerization in the fabrication of surfaces for use in the Life Sciences and Tissue Engineering, highlighting three successful applications of plasma polymerized surfaces. 1. Plasma polymerized acrylic acid surfaces have been used as substrates for the culture and delivery of keratinocytes (skin cells) to chronic wounds. In proof of concept studies weekly delivery of keratinocytes have promoted healing in previously non-healing wounds. These include diabetic foot ulcers and wounds where skin grafts would normally be considered, but were contra-indicated. 2. Surface chemical patterning on the micrometer scale- length, by use of pre-fabricated masks, has been used to control the spatial binding of proteins and cells. This technology makes possible a significant reduction in size of biological assays, reducing the amount of material (e.g. antibody) or cells required. 3. Surface chemical potential gradients, from a few tens of micrometers to a few centrimeters, have been fabricated by "plasma writing", a technique currently being developed in Sheffield. These gradients are being developed to separate mixtures of biomolecules or cells.

  3. Plasma cleaning techniques and future applications in environmentally conscious manufacturing

    SciTech Connect

    Ward, P.P.

    1995-07-01

    Plasmas have frequently been used in industry as a last step surface preparation technique in an otherwise predominantly wet-etch process. The limiting factor in the usefulness of plasma cleaning techniques has been the rate at which organic materials are removed. Recent research in the field of plasma chemistry has provided some understanding of plasma processes. By controlling plasma conditions and gas mixtures, ultra-fast plasma cleaning and etching is possible. With enhanced organic removal rates, plasma processes become more desirable as an environmentally sound alternative to traditional solvent or acid dominated process, not only as a cleaning tool, but also as a patterning and machining tool. In this paper, innovations in plasma processes are discussed including enhanced plasma etch rates via plasma environment control and aggressive gas mixtures. Applications that have not been possible with the limited usefulness of past plasma processes are now approaching the realm of possibility. Some of these possible applications will be discussed along with their impact to environmentally conscious manufacturing.

  4. Study of Cryogenic Complex Plasma

    DTIC Science & Technology

    2010-08-17

    Abdus Salam International Centre for Theoretical Physics, Trieste, Italy). 2. Conference Proceedings 1. J. Kubota, C. Kojima, W. Sekine and O...Cutting Edge Plasma Physics (24-28 August, 2009, ICTP(The Abdus Salam International Centre for Theoretical Physics), Trieste, Italy) 6. W. Sekine

  5. 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.

  6. Development and validation of an UPLC-Q/TOF-MS assay for the quantitation of neopanaxadiol in beagle dog plasma: Application to a pharmacokinetic study.

    PubMed

    Geng, Cong; Wang, Chun-Hong; Hu, Hong; Gao, Xiao-Ping; Gong, Ai-Hua; Lin, Ying-Wei; Fan, Xiu-Shuang; Li, Heng; Yin, Jian-Yuan

    2016-10-27

    Neopanaxadiol (NPD), the main panaxadiol constituent of Panax ginseng C. A. Meyer (Araliaceae), has been regarded as the active component for the treatment of Alzheimer's disease. However, few references are available about pharmacokinetic evaluation for NPD. Accordingly, a rapid and sensitive method for quantitative analysis of NPD in beagle dog plasma based on ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry was developed and validated. Analytes were extracted from plasma by liquid-liquid extraction and chromatographic separation was achieved on an Agilent Zorbax Stable Bond C18 column. Detection was performed in the positive ion mode using multiple reaction monitoring of the transitions both at m/z 461.4 → 425.4 for NPD and internal standard of panaxadiol. All validation parameters, such as lower limit of quantitation, linearity, specificity, precision, accuracy, extraction recovery, matrix effect and stability, were within acceptable ranges and the method was appropriate for multitude sample determination. After oral intake, NPD was slowly absorbed and eliminated from circulatory blood system and corresponding plasma exposure was low. Application of this quantitative method will yield the first pharmacokinetic profile after oral administration of NPD to beagle dog. The information obtained here will be useful to understand the pharmacological effects of NPD.

  7. Studies on Charge Variation and Waves in Dusty Plasmas

    NASA Astrophysics Data System (ADS)

    Kausik, Siddhartha Sankar

    Plasma and dust grains are both ubiquitous ingredients of the universe. The interplay between them has opened up a new and fascinating research domain, that of dusty plasmas, which contain macroscopic particles of solid matter besides the usual plasma constituents. The research in dusty plasmas received a major boost in the early eighties with Voyager spacecraft observation on the formation of Saturn rings. Dusty plasmas are defined as partially or fully-ionized gases that contain micron-sized particles of electrically charged solid material, either dielectric or conducting. The physics of dusty plasmas has recently been studied intensively because of its importance for a number of applications in space and laboratory plasmas. This thesis presents the experimental studies on charge variation and waves in dusty plasmas. The experimental observations are carried out in two different experimental devices. Three different sets of experiments are carried out in two different experimental devices. Three different sets of experiments are carried out to study the dust charge variation in a filament discharge argon plasma. The dust grains used in these experiments are grains of silver. In another get of experiment, dust acoustic waves are studied in a de glow discharge argon plasma. Alumina dust grains are sprinkled in this experiment. The diagnostic tools used in these experiments are Langmuir probe and Faraday cup. The instruments used in these experiments are electrometer, He-Ne laser and charge coupled device (CCD) camera. Langmuir probe is used to measure plasma parameters, while Faraday cup and electrometer are used to measure very low current (~pA) carried by a collimated dust beam. He-Ne laser illuminates the dust grains and CCD camera is used to capture the images of dust acoustic waves. Silver dust grains are produced in the dust chamber by gas-evaporation technique. Due to differential pressure maintained between the dust and plasma chambers, the dust grains move

  8. 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.

  9. 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.

  10. Simultaneous determination of irbesartan and hydrochlorothiazide in human plasma by ultra high performance liquid chromatography tandem mass spectrometry and its application to a bioequivalence study.

    PubMed

    Qiu, Xiangjun; Wang, Zhe; Wang, Bing; Zhan, Hui; Pan, Xiaofeng; Xu, Ren-ai

    2014-04-15

    An ultra high performance liquid chromatography tandem mass spectrometry (U-HPLC-MS/MS) method was developed and validated to determine irbesartan (IRB) and hydrochlorothiazide (HCTZ) in human plasma simultaneously. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard losartan were separated on an Acquity U-HPLC BEH C18 column and mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the negative ion mode. The MRM transitions of m/z 427.2→206.9 and m/z 296.1→204.9 were used to quantify for IRB and HCTZ, respectively. The linearity of this method was found to be within the concentration range of 5-3000ng/mL for IRB, and 0.5-300ng/mL for HCTZ in human plasma, respectively. The lower limit of quantification (LLOQ) was 5ng/mL and 0.5ng/mL for IRB and HCTZ in human plasma, respectively. The relative standard deviations (RSD) of intra and inter precision were less than 12% for both IRB and HCTZ. The analysis time of per sample was 2.5min. The developed and validated method was successfully applied to a bioequivalence study of IRB (300mg) with HCTZ (12.5mg) tablet in Chinese healthy volunteers (N=20).

  11. 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.

  12. 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.

  13. Determination of Sodium Tanshinone IIA Sulfonate in human plasma by LC-MS/MS and its application to a clinical pharmacokinetic study.

    PubMed

    Qin, WeiWei; Wang, Bin; Lu, XiaoPei; Liu, HaiMing; Wang, Li; Qi, WeiLin

    2016-03-20

    An assay based on protein precipitation and liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed and validated for the quantitative analysis of Sodium Tanshinone IIA Sulfonate (STS) in human plasma. After the addition of dehydroepiandrosterone-D5-3-sulfate sodium salt (DHEAS-D5) as internal standard (IS) and formic acid, plasma samples were prepared by one-step protein precipitation with a mixture of acetonitrile and methanol. Isocratic mobile phase consisted of 0.4 mmol/L ammonium formate buffer (16 ppm formic acid)/acetonitrile (40/60, v/v) on a XSELECT™ HSS T3 column. Detection was performed on a triple-quadrupole mass spectrometer utilizing an electrospray ionization (ESI) interface operating in positive ion and selected reaction monitoring (SRM) mode with the precursor to product ion transitions m/z 373.3→357.1 for STS and m/z 373.0→97.8 for the IS. Calibration curves of STS in human plasma were linear (r=0.9957-0.9998) over the concentration range of 2-1000 ng/mL with acceptable accuracy and precision. The lower limit of quantification in human plasma was 2 ng/mL. The validated LC-MS/MS method has been successfully applied to a pharmacokinetic study of STS in Chinese healthy male volunteers.

  14. High-frequency underwater plasma discharge application in antibacterial activity

    NASA Astrophysics Data System (ADS)

    Ahmed, M. W.; Choi, S.; Lyakhov, K.; Shaislamov, U.; Mongre, R. K.; Jeong, D. K.; Suresh, R.; Lee, H. J.

    2017-03-01

    Plasma discharge is a novel disinfection and effectual inactivation approach to treat microorganisms in aqueous systems. Inactivation of Gram-negative Escherichia coli (E. coli) by generating high-frequency, high-voltage, oxygen (O2) injected and hydrogen peroxide (H2O2) added discharge in water was achieved. The effect of H2O2 dose and oxygen injection rate on electrical characteristics of discharge and E. coli disinfection has been reported. Microbial log reduction dependent on H2O2 addition with O2 injection was observed. The time variation of the inactivation efficiency quantified by the log reduction of the initial E. coli population on the basis of optical density measurement was reported. The analysis of emission spectrum recorded after discharge occurrence illustrated the formation of oxidant species (OH•, H, and O). Interestingly, the results demonstrated that O2 injected and H2O2 added, underwater plasma discharge had fabulous impact on the E. coli sterilization. The oxygen injection notably reduced the voltage needed for generating breakdown in flowing water and escalated the power of discharge pulses. No impact of hydrogen peroxide addition on breakdown voltage was observed. A significant role of oxidant species in bacterial inactivation also has been identified. Furthermore the E. coli survivability in plasma treated water with oxygen injection and hydrogen peroxide addition drastically reduced to zero. The time course study also showed that the retardant effect on E. coli colony multiplication in plasma treated water was favorable, observed after long time. High-frequency underwater plasma discharge based biological applications is technically relevant and would act as baseline data for the development of novel antibacterial processing strategies.

  15. Investigations of microwave plasmas - Applications in electrothermal thruster systems

    NASA Technical Reports Server (NTRS)

    Haraburda, Scott S.; Hawley, Martin C.

    1989-01-01

    Experimental studies which have been conducted to develop understanding of plasma processes used for spacecraft propulsion are reviewed. The techniques discussed are calorimetry and volume measurements using the TM 011 and TM 012 modes in the microwave cavity system. The use of plasmas in electrical propulsion and microwave induction is reviewed. Plasma containment, microwave power production, energy distribution, and the pressure and flow dependence of the energy distribution are addressed. The plasma dimensions and their dependence on pressure, flow, and power are considered.

  16. 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.

  17. A tandem mirror plasma source for hybrid plume plasma studies

    NASA Technical Reports Server (NTRS)

    Yang, T. F.; Chang, F. R.; Miller, R. H.; Wenzel, K. W.; Krueger, W. A.

    1985-01-01

    A tandem mirror device to be considered as a hot plasma source for the hybrid plume rocket concept is discussed. The hot plamsa from this device is injected into an exhaust duct, which will interact with an annular hypersonic layer of neutral gas. The device can be used to study the dynamics of the hybrid plume, and to verify the numerical predictions obtained with computer codes. The basic system design is also geared towards low weight and compactness, and high power density at the exhaust. The basic structure of the device consists of four major subsystems: (1) an electric power supply; (2) a low temperature, high density plasma gun, such as a stream gun, an MPD source or gas cell; (3) a power booster in the form of a tandem mirror machine; and (4) an exhaust nozzle arrangement. The configuration of the tandem mirror section is shown.

  18. 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.

  19. Fundamental Mechanisms, Predictive Modeling, and Novel Aerospace Applications of Plasma Assisted Combustion: Laminar Flow Reactor and Nanoparticle Studies at Low to Intermediate Temperatures. Program Overview

    DTIC Science & Technology

    2009-11-04

    dip asma   ue  ox at on an   gn t on mec an sms,  nc u ng  surrogate fuels ‐Development of reduced plasma chemical fuel oxidation...Studies will be conducted to investigate the effects of nanoparticles th l h t i ti d ti ki ti l ion e p asma c arac er s cs an reac on ne cs, e.g

  20. 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.

  1. Optimization and validation of RP-HPLC-UV method with solid-phase extraction for determination of buparvaquone in human and rabbit plasma: application to pharmacokinetic study.

    PubMed

    Venkatesh, Gantala; Majid, M I A; Ramanathan, S; Mansor, S M; Nair, N K; Croft, Simon L; Navaratnam, V

    2008-05-01

    A simple, sensitive and specific reversed-phase high-performance liquid chromatographic method with UV detection at 251 nm was developed for quantitation of buparvaquone (BPQ) in human and rabbit plasma. The method utilizes 250 microL of plasma and sample preparation involves protein precipitation followed by solid-phase extraction. The method was validated on a C18 column with mobile phase consisting of ammonium acetate buffer (0.02 m, pH 3.0) and acetonitrile in the ratio of 18:82 (v/v) at a flow rate of 1.1 mL/min. The calibration curves were linear (correlation coefficient>or=0.998) in the selected range. The method is specific and sensitive with limit of quantitation of 50 ng/mL for BPQ. The validated method was found to be accurate and precise in the working calibration range. Stability studies were carried out at different storage conditions and BPQ was found to be stable. Partial validation studies were carried out using rabbit plasma and intra- and inter-day precision and accuracy were within 7%. This method is simple, reliable and can be routinely used for preclinical pharmacokinetic studies for BPQ.

  2. Advances in the medical research and clinical applications on the plasma DNA.

    PubMed

    Wang, Shuye; Chen, Yuanyuan; Wu, Zhanhe

    2014-04-01

    Plasma DNA has had a strong impact and influence on basic medical research and clinical practice since the discovery of low levels of plasma DNA in healthy individuals under different physiological conditions. Although the source of circulating DNA still requires further investigation, a wide range of research has also proven the value of qualitative and quantitative measurements of plasma DNA in many disease conditions. The use of plasma DNA has a biomarker is advantageous due to accessibility, reliability, reproducibility, sensitivity, specific and relatively low cost. Recently, the detection of circulating (plasma) DNA quantitative changes have been using in the studies on the tumor gene mutations and to monitor disease progressing and to predict the disease prognosis. Such technique also has been using other many different fields, particularly in prenatal diagnosis, for which plasma DNA testing is preferable due to non-invasiveness. This article reviews the research progression and clinical applications of plasma DNA in the last several years.

  3. A new quantitation method of protodioscin by HPLC–ESI-MS/MS in rat plasma and its application to the pharmacokinetic study

    PubMed Central

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

    2016-01-01

    A specific high performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS method) was established for determining the concentration of protodioscin (PG) in rat plasma after intragastric administration of its standard form. Ginsenoside Rb1 was selected as the internal standard (IS). The plasma sample was prepared using one-step deproteinization procedure by adding three parts of acetonitrile to precipitate proteins. The chromatographic separation was accomplished on an Inersil ODS-3 C18 column (250 × 4.6 mm, 5 μm) with a mobile phase composed with acetonitrile and water containing 0.1% formic acid under a gradient elution mode at a flow rate of 1 mL min−1. A 3:1 portion of the eluent after a microsplit was detected on a triple quadrupole tandem mass spectrometer coupled with electrospray ionization (ESI) in positive ion and multiple reaction monitoring (MRM) scanning modes. The mass transitions were selected as 888.1 → 1050.2 for PG and 948.2 → 1110.3 for IS, respectively. After careful validation, the plasma samples were always stable under different storage conditions. These analytical results rendered sensitive, selective, and reliable values by this established method which displayed high accuracy, adequate extracted recoveries, and almost negligible matrix effects. This method was applied to the pharmacokinetic studies on PG level in the rat plasma and its pharmacokinetic effect. The results of our studies suggest that the present method may be a useful tool for further clinical study of PG. PMID:26703445

  4. 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.

  5. Development of a method for the determination of ibafloxacin in plasma by HPLC with flourescence detection and its application to a pharmacokinetic study.

    PubMed

    Marín, Pedro; Cárceles, Carlos M; Escudero, Elisa; Bermejo, Ruperto; Fernández-Varón, Emilio

    2007-01-01

    A simple, rapid, and sensitive high-performance liquid chromatographic method is developed for the determination of ibafloxacin in rabbit plasma. Plasma proteins are precipitated with acetonitrile, and after extraction with methylene chloride followed by desecation, ibafloxacin is determined by reversed-phase chromatography with fluorescence detection exciting at 330 nm and emission at 368 nm. Peaks corresponding to ibafloxacin and the internal standard (salycilic acid) are obtained at 9.8 and 5.2 min, respectively. The method is validated for a limit of quantitation of 10 ng/mL. The intraday relative standard deviation ranges from 4.78-7.15%, and the interday precision ranges from 1.32-4.03%. The method shows linearity for the two calibration curves used (10-100 ng/mL and 100-2000 ng/mL). The procedure described is applied successfully to a pharmacokinetics study of ibafloxacin in rabbits.

  6. A rapid and simple UPLC-MS-MS method for determination of glipizide in human plasma and its application to bioequivalence study.

    PubMed

    Qiu, Xiangjun; Zheng, Shuang-li; Wang, Yingfei; Wang, Rong; Ye, Lei

    2015-01-01

    In this study, a simple, rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry method is described for the determination of glipizide in human plasma samples using carbamazepine as the internal standard (IS) from bioequivalence assays. Sample preparation was accomplished through protein precipitation with methanol, and chromatographic separation was performed on an Acquity BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with gradient profile at a flow rate of 0.4 mL/min. Mass spectrometric analysis was performed using an QTrap5500 mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The multiple reaction monitoring transitions of m/z 446.1 → 321.0 and m/z 237.1 → 194.2 were used to quantify for glipizide and IS. The linearity of this method was found to be within the concentration range of 10-1,500 ng/mL for glipizide in human plasma. Only 1.0 min was needed for an analytical run. The method was applied to a bioequivalence study of two drug products containing glipizide in human plasma samples.

  7. Development and validation of a liquid chromatography-tandem mass spectrometry method for topotecan determination in beagle dog plasma and its application in a bioequivalence study.

    PubMed

    Ye, Ling; Shi, Jian; Wan, Shanhe; Yang, Xiaoshan; Wang, Ying; Zhang, Jiajie; Zheng, Dayong; Liu, Zhongqiu

    2013-11-01

    Topotecan (TPT) is an important anti-cancer drug that inhibits topoisomerase I. A sensitive and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method that potentially determines TPT in beagle dog plasma is needed for a bioequivalence study of TPT formulations. We developed and validated LC-MS/MS to evaluate TPT in beagle dog plasma in terms of specificity, linearity, precision, accuracy, stability, extraction recovery and matrix effect. Plasma samples were treated with an Ostro(TM) sorbent plate (a robust and effective tool) to eliminate phospholipids and proteins before analysis. TPT and camptothecin (internal standard) were separated on an Acquity UPLC BEH C18 column (1.7 µm, 2.1 × 50 mm) with 0.1% formic acid and methanol as the mobile phase at a flow rate of 0.25 mL/min. TPT was analyzed using positive ion electrospray ionization in multiple-reaction monitoring mode. The obtained lower limit of quantitation was 1 ng/mL (signal-to-noise ratio > 10). The standard calibration curve for TPT was linear (correlation coefficient > 0.99) at the concentration range of 1-400 ng/mL. The intra-day and inter-day precision, accuracy, stability, extraction recovery and matrix effect of TPT were within the acceptable limits. The validated method was successfully applied in a bioequivalence study of TPT in healthy beagle dogs.

  8. Simultaneous determination of nimesulide and its four possible metabolites in human plasma by LC-MS/MS and its application in a study of pharmacokinetics.

    PubMed

    Sun, Xiao; Xue, Kai-Lu; Jiao, Xin-Yue; Chen, Qian; Xu, Li; Zheng, Heng; Ding, Yu-Feng

    2016-08-01

    In this study, it was the first time that we simultaneously quantified nimesulide and its possible metabolites M1, M2, M3 and M4 by employing liquid chromatography-tandem mass spectrometry (LC-MS/MS). Nimesulide-d5 was used as internal standard (IS) for validation. Analytes and IS were recovered from human plasma by protein precipitation with acetonitrile. Prepared plasma samples were analyzed under the same LC-MS/MS conditions, and chromatographic separation was realized by using an Ultimate C18 column, with run time being 5min for each sample. Our results showed that various analytes within their concentration ranges could be quantified accurately by using the method. Mean intra- and inter-day accuracies ranged from -4.8% to 4.8% (RE), and intra- and inter-assay precision ≤6.2% (RSD). The following parameters were validated: specificity, recovery, matrix effects, dilution integrity, carry-over, sample stability under a variety of storage and handling conditions (room temperature, freezer, freeze-thaw and post-preparative) and stock solution stability. Pharmacokinetics of nimesulide and its metabolites were calculated based on the analysis of samples collected from twelve Chinese healthy volunteers after single oral dose of 100mg nimesulide tablets. By applying the pharmacokinetic determination into human samples, we preliminarily detected a new metabolite of nimesulide (M4*), and the concentration of M4* was relatively higher in plasma. Furthermore, we predicted part of conceivable metabolism pathway in plasma of after oral administration of 100mg nimesulide tablets. This research provided an experimental basis for further studies on metabolic activation and biotransformation of nimesulide, and for more comprehensive conjecture of its metabolic pathways.

  9. Medical applications of non-thermal atmospheric pressure plasma

    PubMed Central

    Tanaka, Hiromasa; Hori, Masaru

    2017-01-01

    An innovative approach for producing reactive oxygen and nitrogen species is the use of non-thermal atmospheric pressure plasma. The technique has been applied in a wide variety of fields ranging from the micro-fabrication of electric devices to the treatment of disease. Although non-thermal atmospheric pressure plasmas have been shown to be clinically beneficial for wound healing, blood coagulation, and cancer treatment, the underlying molecular mechanisms are poorly understood. In this review, we describe the current progress in plasma medicine, with a particular emphasis on plasma-activated medium (PAM), which is a solution that is irradiated with a plasma and has broadened the applications of plasmas in medicine. PMID:28163379

  10. 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.

  11. Dust trajectories and diagnostic applications beyond strongly coupled dusty plasmas

    SciTech Connect

    Wang Zhehui; Ticos, Catalin M.; Wurden, Glen A.

    2007-10-15

    Plasma interaction with dust is of growing interest for a number of reasons. On the one hand, dusty plasma research has become one of the most vibrant branches of plasma science. On the other hand, substantially less is known about dust dynamics outside the laboratory strongly coupled dusty-plasma regime, which typically corresponds to 10{sup 15} m{sup -3} electron density with ions at room temperature. Dust dynamics is also important to magnetic fusion because of concerns about safety and potential dust contamination of the fusion core. Dust trajectories are measured under two plasma conditions, both of which have larger densities and hotter ions than in typical dusty plasmas. Plasma-flow drag force, dominating over other forces in flowing plasmas, can explain the dust motion. In addition, quantitative understanding of dust trajectories is the basis for diagnostic applications using dust. Observation of hypervelocity dust in laboratory enables dust as diagnostic tool (hypervelocity dust injection) in magnetic fusion. In colder plasmas ({approx}10 eV or less), dust with known physical and chemical properties can be used as microparticle tracers to measure both the magnitude and directions of flows in plasmas with good spatial resolution as the microparticle tracer velocimetry.

  12. Dust Particle Growth and Application in Low Temperature Plasmas

    NASA Astrophysics Data System (ADS)

    Boufendi, L.

    2008-09-01

    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. SiH3-) 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 1011 to 1012 cm-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 SiH4-Ar, CH4, CH4-N2 and Sn(CH3)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 plasmas.

  13. Determination of ketotifen and its conjugated metabolite in human plasma by liquid chromatography/tandem mass spectrometry: application to a pharmacokinetic study.

    PubMed

    Chen, Xiaoyan; Zhong, Dafang; Liu, Dan; Wang, Yingwu; Han, Ying; Gu, Jingkai

    2003-01-01

    A sensitive and specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the investigation of the pharmacokinetics of ketotifen and its major metabolite, ketotifen N-glucuronide, in human plasma. The plasma samples were treated by liquid-liquid extraction and analyzed using LC/MS/MS with an electrospray ionization interface. Diphenhydramine was used as the internal standard. The method had a lower limit of quantitation of 10 pg/mL for ketotifen, which offered increased sensitivity, selectivity and speed of analysis, compared with existing methods. The intra- and inter-day precision were measured to be below 8.2% and accuracy between -2.4% and 3.4% for all QC samples. Incubation of the plasma samples with beta-glucuronidase allowed the quantitation of ketotifen N-glucuronide. This quantitation method was successfully applied to a pharmacokinetic study of ketotifen and its major metabolite after oral administration of 2 mg ketotifen fumarate to 16 healthy volunteers.

  14. Development and validation of a sensitive LC-MS/MS assay for the quantification of nizatidine in human plasma and urine and its application to pharmacokinetic study.

    PubMed

    Shang, De-Wei; Wang, Zhan-Zhang; Ni, Xiao-Jia; Zhang, Ming; Hu, Jin-Qing; Qiu, Chang; Wen, Yu-Guan

    2015-08-15

    We developed and validated a high performance liquid chromatographic method coupled with triple quadrupole mass spectrometry for analysis of nizatidine in human plasma and urine. The biological samples were precipitated with methanol before separation on an Agilent Eclipse Plus C18 column (100mm×46mm, 5μm) with a mixture of methanol and water (95:5, plus 5mM ammonium formate) as the mobile phase at 0.5mL/min. Detection was performed using multiple reaction monitoring modes via electrospray ionization (ESI) at m/z 332.1→155.1 (for nizatidine) and m/z 335.1→155.1 (for [(2)H3]-nizatidine, the internal standard). The linear response range was 5-2000ng/mL and 0.5-80μg/mL for human plasma and urine, with the lower limits of quantification of 5ng/mL and 0.5μg/mL, respectively. The method was validated according to the biological method validation guidelines of the Food and Drug Administration and proved acceptable. This newly developed analytical method was successfully applied in a pharmacokinetic study following single oral administration of a 150mg nizatidine capsule in to 16 healthy Chinese subjects. Maximum and endpoint concentrations in plasma and urine were quantifiable, suggesting our method is appropriate for routine pharmacokinetic analysis.

  15. Quantitation of niflumic acid in human plasma by high-performance liquid chromatography with ultraviolet absorbance detection and its application to a bioequivalence study of talniflumate tablets.

    PubMed

    Lee, H W; Won, K J; Cho, S H; Ha, Y H; Park, W S; Yim, H T; Baek, M; Rew, J H; Yoon, S H; Yim, S V; Chung, J H; Lee, K T

    2005-07-25

    A rapid and simple HPLC method with UV detection (288 nm) was developed and validated for quantitation of niflumic acid in human plasma, the active metabolite of talniflumate. After precipitation with 100% methanol containing the internal standard, indomethacin, the analysis of the niflumic acid level in the plasma samples was carried out using a reverse phase C18 CAPCELL PAK (5 microm, 4.6 mm x 250 mm) column. The chromatographic separation was accomplished with an isocratic mobile phase consisting of a mixture of 0.1M sodium acetate in water and acetonitrile (37:63, v/v), adjusted to pH 6.4. This HPLC method was validated by examining its precision and accuracy for inter- and intra-day runs in a linear concentration range of 0.02-5.00 microg/mL. Stability of niflumic acid in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method was successfully applied to the bioequivalence study of talniflunate in healthy volunteers.

  16. Simultaneous determination of total homocysteine, cysteine, cysteinylglycine, and glutathione in human plasma by high-performance liquid chromatography: application to studies of oxidative stress.

    PubMed

    Nolin, Thomas D; McMenamin, M Elizabeth; Himmelfarb, Jonathan

    2007-06-01

    A sensitive, reproducible, and robust high-performance liquid chromatography (HPLC) method has been validated for simultaneously determining total concentrations of the aminothiols homocysteine, cysteine, cysteinylglycine, and glutathione in human plasma. Plasma aminothiols are reduced via incubation with tris-(2-carboxyethyl)-phosphine hydrochloride, followed by protein precipitation with trichloroacetic acid and derivatization with ammonium-7-fluorobenzo-2-oxa-1,3-diazole-4-sulfonic acid. Separation of aminothiols and the internal standard mercaptopropionylglycine is achieved using reversed-phase HPLC conditions and fluorescence detection. Excellent linearity is observed for all analytes over their respective concentration ranges with correlation coefficients (r) > 0.99. The intra- and inter-day precision and accuracy were within +/-10%. This method utilizes an internal standard, employs phosphate buffered saline-based standards and quality controls, and demonstrates excellent plasma recovery and improved sensitivity. This assay is well suited for high-throughput quantitative determination of aminothiols in clinical studies, and is currently being used to support investigations of oxidative stress in patients with chronic kidney disease.

  17. Quantification of carbamazepine and its 10,11-epoxide metabolite in rat plasma by UPLC-UV and application to pharmacokinetic study.

    PubMed

    Beig, Avital; Dahan, Arik

    2014-07-01

    A rapid, selective and sensitive UPLC-UV method was developed and validated for the quantitative analysis of carbamazepine and its epoxide metabolite in rat plasma. A relatively small volume of plasma sample (200 μL) is required for the described analytical method. The method includes simple protein precipitation, liquid-liquid extraction, evaporation, and reconstitution steps. Samples were separated on a Waters Acquity UPLC BEH C18 column (1.7 µm, 2.1 × 100 mm) with a gradient mobile phase consisted of 60:40 going to 40:60 (v/v) water-acetonitrile at a flow rate of 0.5 mL/min. The total run time was as low as 6 min, representing a significant improvement in comparison to existing methods. Excellent linearity (r(2)  > 0.999) was achieved over a wide concentration range. Close to complete recovery, short analysis time, high stability, accuracy, precision and reproducibility, and low limit of quantitation were demonstrated. Finally, we successfully applied this analytical method to a pre-clinical oral pharmacokinetic study, revealing the plasma profiles of both carbamazepine and carbamazepine-10,11-epoxide following oral administration of carbamazepine to rats. The advantages demonstrated in this work make this analytical method both time- and cost-efficient approach for drug and metabolite monitoring in the pre-clinical/clinical laboratory.

  18. 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.

  19. 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.

  20. Liquid chromatography tandem mass spectrometry method for the quantitative analysis of ceritinib in human plasma and its application to pharmacokinetic studies.

    PubMed

    Heudi, Olivier; Vogel, Denise; Lau, Yvonne Y; Picard, Franck; Kretz, Olivier

    2014-11-01

    Ceritinib is a highly selective inhibitor of an important cancer target, anaplastic lymphoma kinase (ALK). Because it is an investigational compound, there is a need to develop a robust and reliable analytical method for its quantitative determination in human plasma. Here, we report the validation of a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the rapid quantification of ceritinib in human plasma. The method consists of protein precipitation with acetonitrile, and salting-out assisted liquid-liquid extraction (SALLE) using a saturated solution of sodium chloride prior to analysis by LC-MS/MS with electrospray ionization (ESI) technique in positive mode. Samples were eluted at 0.800 mL min(-1) on Ascentis Express® C18 column (50 mm × 2.1 mm, 2.7 μm) with a mobile phase made of 0.1 % formic acid in water (A) and 0.1 % formic acid in acetonitrile (B). The method run time was 3.6 min and the low limit of quantification (LLOQ) was estimated at 1.00 ng mL(-1) when using 0.100 mL of human plasma. The assay was fully validated and the method exhibited sufficient specificity, accuracy, precision, and sensitivity. In addition, recovery data and matrix factor (MF) in normal and in hemolyzed plasmas were assessed, while incurred samples stability (ISS) for ceritinib was demonstrated for at least 21 months at a storage temperature of -65 °C or below. The method was successfully applied to the measurement of ceritinib in clinical samples and the data obtained on incurred samples reanalysis (ISR) showed that our method was reliable and suitable to support the analysis of samples from the clinical studies.

  1. 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.

  2. Optimizing high-performance liquid chromatography method for quantification of glucosamine using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate derivatization in rat plasma: application to a pharmacokinetic study.

    PubMed

    Wang, Xianhuo; Chen, Xiang; Chen, Lijuan; Wang, Biqin; Peng, Cheng; He, Chunmei; Tang, Minghai; Zhang, Fan; Hu, Jia; Li, Rui; Zhao, Xia; Wei, Yuquan

    2008-11-01

    A sensitive and reliable HPLC method with fluorescence detection based on the precolumn derivatization of glucosamine with 6-aminoquinolyl-N-hydroxylsuccinimidyl carbamate (AQC) was established for the quantitative determination of glucosamine in rat plasma. The plasma protein was precipitated by acetonitrile, followed by vortex mixing and centrifugation. The supernatant was divided into the organic layer and aqueous layer by adding sodium chloride, and then the aqueous layer was derivatized with AQC in 0.2 M borate buffer of pH 8.8 before the HPLC analysis. An amino acid analysis column (3.9 x 150 mm, 4 microm) was applied, with 140 mM sodium acetate buffer (pH = 5.25) and acetonitrile as mobile phase at a flow rate of 1 mL/min. A linear correlation coefficient of 0.9987 was calculated within the range of 0.1-30 microg/mL of the standard curve for glucosamine. The limit of detection was 30 ng/mL. The intra- and inter-day precisions (as RSD) were less than 7.38 and 12.72%, respectively. The intra- and inter-day accuracy ranged from 91.8 to 110.0%. Extraction recoveries of glucosamine in plasma were more than 90%. The validated method was successfully applied for the quantitative determination of glucosamine in rat plasma and evaluation for pharmacokinetic study of glucosamine. It was also possible to be applied for the quantitative determination of other compounds containing amino group in biological samples.

  3. 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.

  4. 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.

  5. 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.

  6. 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.-

  7. 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.

  8. Quantitative analysis of tenuifolin concentrations in rat plasma and tissue using LC⬜MS/MS: application to pharmacokinetic and tissue distribution study.

    PubMed

    Ma, Bo; Li, Xiaotian; Li, Jing; Zhang, Qi; Liu, Yinhui; Yang, Xiaojing; Sun, Jingjing; Yao, Di; Liu, Lei; Liu, Xiaoxin; Ying, Hanjie

    2014-01-01

    A sensitive, reliable and accurate reversed-phased liquid chromatography with tandem mass spectrometry (LC⬜MS/MS) in negative ion mode was developed and validated for the quantification of tenuifolin in rat plasma and tissue. A single step protein precipitation by methanol was used to prepare plasma and tissue homogenate samples. Tenuifolin and polydatin (internal standard, IS) were separated by HPLC using a C18 column and an isocratic mobile phase consisted of acetonitrile and water containing 0.05% formic acid (42:58, v/v) running at a flow rate of 0.2 ml/min for 6 min. Detection and quantification were performed using a mass spectrometer by the multiple reaction monitoring (MRM) in negative electrospray ionization mode. The transition monitored were m/z [M↙H](↙) 679.4 ⠙ 455.4 for tenuifolin and m/z [M↙H](↙) 389.0 ⠙ 227.2 for IS, respectively. Calibration curves were recovered over a concentration range of 0.5⬜1000 ng/ml for plasma, heart, liver, lung and kidney, 0.5⬜200 ng/ml for spleen, and 0.5⬜50 ng/ml for brain, respectively. The lower limit of quantification was 0.5 ng/ml for plasma and tissue homogenates. The inter-day precision (R.S.D.) was less than 12.9% and intra-day precision R.S.D. was less than 13.4%, while the inter-day accuracy (R.E.) was ranged from ↙7.20 to 6.87% and intra-day accuracy (R.E.) was ranged from ↙6.20 to 8.04% in plasma and tissue homogenates. This method was successfully applied to the pharmacokinetic and tissue distribution study of pure tenuifolin in rat. The pharmacokinetic study indicated that poor absorption into systemic circulation was observed after rat was administered orally tenuifolin, and the absolute bioavailability was low (0.83 ± 0.28%). The results of tissue distribution showed the higher tenuifolin concentrations were found in liver, kidney and heart, and the small amount of drug was distributed quickly into the brain tissue at 5 min after the intravenous injection of tenuifolin

  9. 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.

  10. 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.

  11. 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

  12. TEBPP: Theoretical and Experimental study of Beam-Plasma-Physics

    NASA Technical Reports Server (NTRS)

    Anderson, H. R.; Bernstein, W.; Linson, L. M.; Papadopoulos, K.; Kellogg, P. J.; Szuszczewicz, E. P.; Hallinan, T. J.; Leinbach, H.

    1980-01-01

    The interaction of an electron beam (0 to 10 keV, 0 to 1.5 Amp) with the plasma and neutral atmospheres at 200 to 400 km altitude is studied with emphasis on applications to near Earth and cosmical plasmas. The interaction occurs in four space time regions: (1) near electron gun, beam coming into equilibrium with medium; (2) equilibrium propagation in ionosphere; (3) ahead of beam pulse, temporal and spatial precursors; (4) behind a beam pulse. While region 2 is of the greatest interest, it is essential to study Region 1 because it determines the characteristics of the beam as it enters 2 through 4.

  13. 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.

  14. 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.

  15. Vacuum application of thermal barrier plasma coatings

    NASA Technical Reports Server (NTRS)

    Holmes, R. R.; Mckechnie, T. N.

    1988-01-01

    Coatings are presently applied to Space Shuttle Main Engine (SSME) turbine blades for protection against the harsh environment realized in the engine during lift off-to-orbit. High performance nickel, chromium, aluminum, and yttrium (NiCrAlY) alloy coatings, which are applied by atmospheric plasma spraying, crack and spall off because of the severe thermal shock experienced during start-up and shut-down of the engine. Ceramic coatings of yttria stabilized zirconia (ZrO2-Y2O3) were applied initially as a thermal barrier over coating to the NiCrAlY but were removed because of even greater spalling. Utilizing a vacuum plasma spraying process, bond coatings of NiCrAlY were applied in a low pressure atmosphere of argon/helium, producing significantly improved coating-to-blade bonding. The improved coatings showed no spalling after 40 MSFC burner rig thermal shock cycles, cycling between 1700 and -423 F. The current atmospheric plasma NiCrAlY coatings spalled during 25 test cycles. Subsequently, a process was developed for applying a durable thermal barrier coating of ZrO2-Y2O3 to the turbine blades of first stage high-pressure fuel turbopumps utilizing the vacuum plasma process. The improved thermal barrier coating has successfully passed 40 burner rig thermal shock cycles without spalling. Hot firing in an SSME turbine engine is scheduled for the blades. Tooling was installed in preparation for vacuum plasma spray coating other SSME hardware, e.g., the titanium main fuel valve housing (MFVH) and the fuel turbopump nozzle/stator.

  16. 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.

  17. 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.

  18. Simultaneous quantification of VX and its toxic metabolite in blood and plasma samples and its application for in vivo and in vitro toxicological studies.

    PubMed

    Reiter, Georg; Mikler, John; Hill, Ira; Weatherby, Kendal; Thiermann, Horst; Worek, Franz

    2011-09-15

    The present study was initiated to develop a sensitive and highly selective method for the simultaneous quantification of the nerve agent VX (O-ethyl S-[2(diisopropylamino)ethyl] methylphosphonothioate) and its toxic metabolite (EA-2192) in blood and plasma samples in vivo and in vitro. For the quantitative detection of VX and EA-2192 the resolution was realized on a HYPERCARB HPLC phase. A specific procedure was developed to isolate both toxic analytes from blood and plasma samples. The limit of detection was 0.1 pg/ml and the absolute recovery of the overall sample preparation procedure was 74% for VX and 69% for EA-2192. After intravenous and percutaneous administration of a supralethal doses of VX in anaesthetised swine both VX and EA-2192 could be quantified over 540 min following exposure. This study is the first to verify the in vivo formation of the toxic metabolite EA-2192 after poisoning with the nerve agent VX. Further toxicokinetic and therapeutic studies are required in order to determine the impact of EA-2192 on the treatment of acute VX poisoning.

  19. PEEK tube-based online solid-phase microextraction-high-performance liquid chromatography for the determination of yohimbine in rat plasma and its application in pharmacokinetics study.

    PubMed

    Xiang, Xiaowei; Shang, Bing; Wang, Xiaozheng; Chen, Qinhua

    2017-04-01

    Yohimbine is a novel compound for the treatment of erectile dysfunction derived from natural products, and pharmacokinetic study is important for its further development as a new medicine. In this work, we developed a novel PEEK tube-based solid-phase microextraction (SPME)-HPLC method for analysis of yohimbine in plasma and further for pharmacokinetic study. Poly (AA-EGDMA) was synthesized inside a PEEK tube as the sorbent for microextraction of yohimbine, and parameters that could influence extraction efficiency were systematically investigated. Under optimum conditions, the PEEK tube-based SPME method exhibits excellent enrichment efficiency towards yohimbine. By using berberine as internal standard, an online SPME-HPLC method was developed for analysis of yohimbine in human plasma sample. The method has wide linear range (2-1000 ng/mL) with an R(2) of 0.9962; the limit of detection was determined and was as low as 0.1 ng/mL using UV detection. Finally, a pharmacokinetic study of yohimbine was carried out by the online SPME-HPLC method and the results have been compared with those of reported methods.

  20. A fast, sensitive and simple method for mirtazapine quantification in human plasma by HPLC-ESI-MS/MS. Application to a comparative bioavailability study.

    PubMed

    Borges, Ney Carter; Barrientos-Astigarraga, Rafael Eliseo; Sverdloff, Carlos Eduardo; Donato, José Luiz; Moreno, Patricia; Felix, Leila; Galvinas, Paulo Alexandre Rebelo; Moreno, Ronilson Agnaldo

    2012-11-01

    In the present study a simple, fast, sensitive and robust method to quantify mirtazapine in human plasma using quetiapine as the internal standard (IS) is described. The analyte and the IS were extracted from human plasma by a simple protein precipitation with methanol and were analyzed by high-performance liquid chromatography coupled to an electrospray tandem triple quadrupole mass spectrometer (HPLC-ESI-MS/MS). Chromatography was performed isocratically on a C(18), 5 µm analytical column and the run time was 1.8 min. The lower limit of quantitation was 0.5 ng/mL and a linear calibration curve over the range 0.5-150 ng/mL was obtained, showing acceptable accuracy and precision. This analytical method was applied in a relative bioavailability study in order to compare a test mirtazapine 30 mg single-dose formulation vs a reference formulation in 31 volunteers of both sexes. The study was conducted in an open randomized two-period crossover design and with a 14 day washout period. Since the 90% confidence interval for C(max) , AUC(last) and AUC(0-inf) were within the 80-125% interval proposed by the Food and Drug Administration and ANVISA (Brazilian Health Surveillance Agency), it was concluded that mirtazapine 30 mg/dose is bioequivalent to the reference formulation, according to both the rate and extent of absorption.

  1. 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.

  2. 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.

  3. Validated LC-MS/MS method for quantification of gabapentin in human plasma: application to pharmacokinetic and bioequivalence studies in Korean volunteers.

    PubMed

    Park, Jin-Hee; Jhee, Ok-Hwa; Park, Song-Hee; Lee, Jung-Sik; Lee, Min-Ho; Shaw, Leslie M; Kim, Kwang-Hyun; Lee, Jong-Ho; Kim, Yong-Seok; Kang, Ju-Seop

    2007-08-01

    A sensitive validated liquid chromatography-tandem mass spectrometric method (LC-MS/MS) for gabapentin (GB) in human plasma has been developed and applied to pharmacokinetic (PK) and bioequivalence (BE) studies in human. In a randomized crossover design with a 1-week period, each subject received a 300 mg GB capsule. The procedure involves a simple protein precipitation with acetonitrile and separated by LC with a Gemini C(18) column using acetonitrile-10 mm ammonium acetate (20:80, v/v, pH 3.2) as mobile phase. The GB and internal standard [(S)-(+)-alpha-aminocyclohexanepropionic acid hydrate] were analyzed using an LC-API 2000 MS/MS in multiple reaction monitoring mode. The ionization was optimized using ESI(+) and selectivity was achieved using MS/MS analysis, m/z 172.0 --> 154.0 and m/z 172.0 --> 126.0 for GB and IS, respectively. The assay exhibited good linearity over a working range of 20-5000 ng/mL for GB in human plasma with a lower limit of quantitation of 20 ng/mL. No endogenous compounds were found to interfere with the analysis. The accuracy and precision were shown for concentrations over the standard ranges. This method was successfully applied for the PK and BE studies by analysis of blood samples taken up to 36 h after an oral dose of 300 mg of GB in 24 healthy volunteers.

  4. Enantioselective determination of (R)- and (S)-lansoprazole in human plasma by chiral liquid chromatography with mass spectrometry and its application to a stereoselective pharmacokinetic study.

    PubMed

    Sun, Luning; Cao, Yang; Jiao, Huiwen; Fang, Yunqian; Yang, Zhicheng; Bian, Mingliang; Zhang, Hongwen; Gong, Xiaojian; Wang, Yongqing

    2015-11-01

    A simple and enantioselective method was developed and validated for the simultaneous determination of (R)- and (S)-lansoprazole in human plasma by chiral liquid chromatography with tandem mass spectrometry. Lansoprazole enantiomers and internal standard (esomeprazole) were extracted from plasma using acetonitrile as protein precipitating agent. Baseline chiral separation was achieved within 9.0 min on a Chiralpak IC column (150 mm × 4.6 mm, 5 μm) with the column temperature of 30°C. The mobile phase consisted of 10 mM ammonium acetate solution containing 0.05% acetic acid/acetonitrile (50:50, v/v). The mass spectrometric analysis was performed using a QTrap 5500 mass spectrometer coupled with an electrospray ionization source in positive ion mode. The multiple reactions monitoring transitions of m/z 370.1→252.1 and 346.1→198.1 were used to quantify lansoprazole enantiomers and esomeprazole, respectively. For each enantiomer, no apparent matrix effect was found, the calibration curve was linear over 5.00-3000 ng/mL, the intra- and inter-day precisions were below 10.0%, and the accuracy was -3.8 to 3.3%. Analytes were stable during the study. No chiral inversion was observed during sample storage, preparation procedure and analysis. The method was applied to the stereoselective pharmacokinetic studies in human after intravenous administration of dexlansoprazole or racemic lansoprazole.

  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.

  6. Determination of cetirizine in human plasma using high performance liquid chromatography coupled with tandem mass spectrometric detection: application to a bioequivalence study.

    PubMed

    Ren, Xiao-Lei; Tian, Yuan; Zhang, Zun-Jian; Chen, Yun; Wu, Li-Li; Huang, Jun

    2011-01-01

    A rapid, sensitive and selective HPLC-MS/ MS method was developed and validated for the quantification of cetirizine dihydrochloride (CAS 83881-51-0) in human plasma using mosapride citrate as internal standard (IS, CAS 112885-42-4). Following liquid-liquid extraction, the analytes were separated using a mobile phase consisting of methanol and aqueous ammonium acetate solution (10 mM) (60:40, v/v) on a reverse phase C18 column and analyzed by a triple-quadrupole mass spectrometer in the selected reaction monitoring (SRM) mode using the respective [M+H]+ ions, m/z 398 --> 201 for cetirizine and m/z 422 --> 198 for mosapride. The analysis time for each run was 8.0 min. The assay exhibited a linear dynamic range of 0.5-500 ng/ml for cetirizine dihydrochloride in human plasma. The lower limit of quantification (LLOQ) was 0.5 ng/ml with a relative standard deviation of less than 15% (all the concentration data in this study related to the salt (cetirizine dihydrochloride)). 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 has been successfully applied to a bioequivalence study in 20 healthy male Chinese volunteers.

  7. A rapid and sensitive UHPLC-MS/MS assay for the determination of trelagliptin in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Hu, Xiao-Xia; Lan, Tian; Chen, Zhe; Yang, Cheng-Cheng; Tang, Peng-Fei; Yuan, Ling-Jing; Hu, Guo-Xin; Cai, Jian-Ping

    2016-10-15

    This study aims to develop and validate a simple, rapid and sensitive ultra-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) method for exploring pharmacokinetic characteristics of trelagliptin. Protein precipitation by acetonitrile was used to prepare plasma sample. A RRHD Eclipse Plus C18 (2.1×50mm, 1.8μ) column with gradient mobile phase (containing acetonitrile and 0.1% formic acid) help to achieve the separation of trelagliptin and carbamazepine (IS) with high selectivity. Detection of target fragment ions m/z 358.2→133.9 for trelagliptin, and m/z 237.1→194.0 for IS was performed in positive-ion electrospray ionization mass spectrometry by multiple reaction monitoring. Linear calibration plots were achieved in the range of 5-4000ng/mL for trelagliptin (R(2)=0.999) in rat plasma. The recovery of trelagliptin ranged from 87.8% to 93.7%. The method was showed to be accurate, precise and stable. No obvious matrix effect was found. It has been fully validated and successfully applied to pharmacokinetic study of trelagliptin.

  8. Simultaneous determination of eight bioactive components of Qishen Yiqi Dripping Pills in rat plasma using UFLC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Shao, Yaping; Zhang, Wen; Tong, Ling; Huang, Jingyi; Li, Dongxiang; Nie, Wei; Zhu, Yan; Li, Yunfei; Lu, Tao

    2017-02-01

    In this study, a rapid and reliable ultra-fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed and validated for the simultaneous determination of eight active ingredients, including astragaloside IV (AIV), ononin (ONO), tanshinol (TSL), protocatechualdehyde (PCA), protocatechuic acid (PA), salvianolic acid D (SAD), rosmarinic acid (RA), and ginsenoside Rg1 (GRg1 ), in rat plasma. The plasma samples were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on a Waters Acquity UPLC® BEH C18 column (1.7 µm particles, 2.1 × 100 mm).The mobile phase consisted of 0.1% aqueous formic acid (A)-acetonitrile with 0.1% formic acid (B) at a flow rate of 0.4 mL/min. Quantification was performed on a triple quadruple tandem mass spectrometry with electrospray ionization by multiple reaction monitoring both in the negative and positive ion mode. The lower limit of quantification (LLOQ) of TSL was 2.0 ng/mL and the others were 5.0 ng/mL. The extraction recoveries, matrix effects, intra- and inter-day precision and accuracy of eight tested components were all within acceptable limits. The validated method was successfully applied to the pharmacokinetic study of the eight active constituents after intragastric administration of three doses (1.0, 3.0, 6.0 g/kg body weight) of Qishen Yiqi dripping pills to rats.

  9. 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.

  10. 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.

  11. Analysis of 21-hydroxy deflazacort in human plasma by UPLC-MS/MS: application to a bioequivalence study in healthy volunteers.

    PubMed

    Patel, Daxesh P; Sharma, Primal; Patel, Bhargav M; Sanyal, Mallika; Singhal, Puran; Shrivastav, Pranav S

    2013-11-01

    A sensitive and rapid ultra performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method has been developed for the determination of 21-hydroxy deflazacort in human plasma using betamethasone as the internal standard (IS). After solid-phase extraction from 100 μL human plasma, the analyte and IS were analyzed on Waters Acquity UPLC BEH C18 (50 mm × 2.1 mm, 1.7 μm) column using acetonitrile-4.0mM ammonium formate, pH 3.5 (90:10, v/v) as the mobile phase. The protonated analyte was quantified by selected reaction monitoring in the positive ionization mode by triple quadrupole mass spectrometer. The calibration plots were linear over the concentration range 0.50-500 ng/mL. Intra-batch and inter-batch precision (% CV) and accuracy (%) for five quality control samples ranged within 1.40-4.82% and 98.0-102.0% respectively. The overall mean extraction recovery of 21-hydroxy deflazacort from plasma ranged from 95.3 to 97.3%. Matrix effect was assessed by post-column analyte infusion and the extraction recovery was >95.0% across four quality control levels for the analyte and IS. Stability was evaluated under different conditions like bench top, autosampler, processed sample (at room temperature and in cooling chamber), freeze-thaw and long term stability. The method was applied to support a bioequivalence study of 30 mg deflazacort tablet formulation in 28 healthy subjects. Assay reproducibility was demonstrated by reanalysis of 115 incurred samples.

  12. Simultaneous quantification of lenalidomide, ibrutinib and its active metabolite PCI-45227 in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

    PubMed

    Veeraraghavan, Sridhar; Viswanadha, Srikant; Thappali, Satheeshmanikandan; Govindarajulu, Babu; Vakkalanka, Swaroopkumar; Rangasamy, Manivannan

    2015-03-25

    Efficacy assessments using a combination of ibrutinib and lenalidomide necessitate the development of an analytical method for 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 lenalidomide, ibrutinib, and its active metabolite PCI45227 in rat plasma. Extraction of lenalidomide, ibrutinib, PCI45227 and tolbutamide (internal standard; IS) from 50 μl rat plasma was carried out by liquid-liquid extraction with ethyl acetate:dichloromethane (90:10) ratio. Chromatographic separation of analytes was performed on YMC pack ODS AM (150 mm × 4.6 mm, 5 μm) column under gradient conditions with acetonitrile:0.1% formic acid buffer as the mobile phases at a flow rate of 1 ml/min. Precursor ion and product ion transition for 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 0.72-183.20 ng/ml for ibrutinib, 0.76-194.33 ng/ml for PCI-45227 and 1.87-479.16 ng/ml for lenalidomide. Mean extraction recovery for ibrutinib, PCI-45227, lenalidomide and IS of 75.2%, 84.5%, 97.3% and 92.3% 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 was evaluated for all the analytes. The analytical method was applied to support a pharmacokinetic study of simultaneous estimation of lenalidomide, ibrutinib, and its active metabolite PCI-45227 in Wistar rat. Assay reproducibility was demonstrated by re-analysis of 18 incurred samples.

  13. Gradient high-performance liquid chromatography for the simultaneous determination of chlorogenic acid and baicalin in plasma and its application in the study of pharmacokinetics in rats.

    PubMed

    Gao, Rong; Zheng, Qiang; Gong, Tao; Fu, Yao; Deng, Li; Zhang, Zhi-Rong

    2007-01-04

    A novel HPLC-UV method was developed for the simultaneous determination of two major active components in Yinhuang injection, chlorogenic acid and baicalin, in rat plasma. Extracted from the plasma samples with methanol-acetonitrile (3:1, v/v), the two compounds were successfully separated using a C18 column with a gradient elution composed of 15 and 54% methanol-acetonitrile (1:1, v/v) in 0.2% (v/v) phosphoric acid water solution (pH 2.0). The flow-rate was set at 1 ml min(-1) and the eluent was detected at 327 nm for chlorogenic acid, 278 nm for baicalin. Puerarin and rutin were used as the internal standards for chlorogenic acid and baicalin, respectively. The method was linear over the range of 0.388-12.4 microg ml(-1), 0.485-124 microg ml(-1) for chlorogenic acid and baicalin, respectively. The correlation coefficient for each analyte was above 0.998. The intra-day and inter-day precisions were better than 7 and 9%, with the relative error ranging from -9.5 to 7.3% and from -4.2 to 1.8%. The limit of detection (LOD) and the limit of quantification (LOQ) for chlorogenic acid and baicalin in plasma were 0.194, 0.122, 0.388 and 0.485 microg ml(-1), respectively. This assay has been successfully applied in the pharmacokinetic study of chlorogenic acid and baicalin in vivo through intravenous administration of Yinhuang injection to rats.

  14. 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.

  15. Optimization and validation of an ion-pair RP-HPLC-UV method for the determination of total free iodine in rabbit plasma: application to a pharmacokinetic study.

    PubMed

    Cui, Lijun; Wen, Jun; Zhou, Tingting; Wang, Shuowen; Fan, Guorong

    2009-11-01

    An ion-pair reverse-phase high performance liquid chromatographic method with UV-vis detection has been developed for the determination of total free iodine in rabbit plasma after vaginal administration of povidone-iodine (PVP-I). Sample preparation was done by protein precipitation with acetonitrile in 96-well format and aspirin was used as the internal standard. The 100 microL sodium thiosulfate solution (5 g L(-1)) was added to 100 microL plasma sample before protein precipitation, to convert the total free iodine in plasma to iodide (I(-)). Separation was performed on a C(18) column (200 x 4.6 mm i.d., 5 microm). The mobile phase consisting of a mixture of water phase (containing 10 mmol L(-1) 18-crown-6 ether, 5 mmol L(-1) octylamine and 5 mmol L(-1) sodium dihydrogen phosphate, pH adjusted to 6.0 with phosphoric acid) and acetonitrile in the ratio 70:30 (v/v) was delivered isocraticly at a flow rate of 1.0 mL min(-1). The method was sensitive with a lower limit of quantification of 0.005 microg mL(-1), with good linearity (r(2) > 0.9990) over the linear range of 0.005-2 microg mL(-1). All the validation data, such as linearity, accuracy and precision, were within the required limits. The method was successfully applied to study the pharmacokinetic of PVP-I in rabbits after vaginal administration.

  16. 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

    2016-01-05

    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.

  17. 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.

  18. 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.

  19. Stereoselective determination of ginsenosides Rg3 and Rh2 epimers in rat plasma by LC-MS/MS: application to a pharmacokinetic study.

    PubMed

    Bae, Soo Hyeon; Zheng, Yu Fen; Yoo, Young Hyo; Kim, Jeom Yong; Kim, Sun Ok; Jang, Min Jung; Seo, Jae Hong; Bae, Soo Kyung

    2013-06-01

    We developed and validated an accurate and sensitive LC-MS/MS method for the simultaneous quantitation of ginsenoside Rg3 and Rh2 epimers (R-Rg3, S-Rg3, R-Rh2, and S-Rh2) in rat plasma. Analytes were extracted from 0.1 mL aliquots of rat plasma by liquid-liquid extraction, using 2 mL of ethyl acetate. In this assay, dioscin (500 ng/mL) was used as an internal standard. Chromatographic separation was conducted using an Acclaim RSLC C18 column (150 × 2.1 mm, 2.2 μm) at 40°C, with a gradient mobile phase consisting of 0.1% formic acid in distilled water and in acetonitrile, a flow rate of 0.35 mL/min, and a total run time of 20 min. Detection and quantification were performed using a mass spectrometer in selected reaction-monitoring mode with negative electrospray ionization at m/z 783.4 → 161.1 for R-Rg3 and S-Rg3, m/z 621.3 → 161.1 for R-Rh2 and S-Rh2, and m/z 867.2 → 761.5 for the internal standard. For R-Rg3 and S-Rg3, the lower limit of quantification was 5 ng/mL, with a linear range up to 500 ng/mL; for R-Rh2 and S-Rh2, the lower limit of quantification was 150 ng/mL, with a linear range up to 6000 ng/mL. The coefficient of variation for assay precision was less than 10.5%, with an accuracy of 86.4-112%. No relevant cross-talk or matrix effect was observed. The method was successfully applied to a pharmacokinetic study after oral administration of 400 mg/kg and 2000 mg/kg of BST204, a fermented ginseng extract, to rats. We found that the S epimers exhibited significantly higher plasma concentrations and area under curve values for both Rg3 and Rh2. This is the first report on the separation and simultaneous quantification of R-Rg3, S-Rg3, R-Rh2, and S-Rh2 in rat plasma by LC-MS/MS. The method should be useful in the clinical use of ginseng or its derivatives.

  20. A liquid chromatographic-electrospray-tandem mass spectrometric method for quantitation of quetiapine in human plasma and liver microsomes: application to study in vitro metabolism.

    PubMed

    Lin, Shen-Nan; Chang, Yan; Moody, David E; Foltz, Rodger L

    2004-09-01

    Quetiapine is an atypical antipsychotic agent for the treatment of schizophrenia. After an oral dose it is absorbed rapidly and extensively metabolized in the liver, resulting in low plasma concentrations of the parent drug. A sensitive analytical method is needed. A liquid chromatographic-electrospray-tandem mass spectrometric (LC-ESI-MS-MS) method combined with a simple liquid-liquid extraction has been developed for the measurement of quetiapine in human plasma and in human liver microsomes (HLM). Clozapine is used as internal standard. Plasma samples or microsomes quenched with methanol (100 microL) were made basic and extracted with 3 mL n-butyl chloride. The reconstituted extracts were analyzed by LC-ESI-MS-MS. Selective reaction monitoring of MH(+) at m/z 384 and 327 resulted in strong fragment ions at m/z 253 and 192 for quetiapine and clozapine, respectively. Recovery of quetiapine and clozapine ranged from 62 to 73%. Intrarun accuracy and precision determined at 1.0 (lower limit of quantitation), 2.5, 200, and 400 ng/mL did not exceed 7% deviation from target and the %CV did not exceed 5.5%. The % target +/- %CV for interrun accuracy and precision were at least 95% +/- 7.4% at concentrations of 2.5, 200, and 400 ng/mL. Plasma samples (2.5 and 400 ng/mL) stored at room temperature for 24 h or after 3 cycles of freeze/thaw were all stable (maximum % deviation < or = 11.0%). Processed extracts (2.5 and 400 ng/mL) stored for 7 days at -20 degrees C or 6 days on the autosampler were all stable (maximum % deviation < or = 11.5%). The method has been used to study quetiapine utilization during incubation with HLM or with cDNA-expressed human cytochrom P450s (CYP). Quetiapine is extensively metabolized by CYP 3A4 and CYP 2D6 and to a lesser extent by CYP 3A7, CYP 3A5, and CYP 2C19.

  1. 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.

  2. 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.

  3. Highly Sensitive LC-MS-MS Method for the Determination of Tacrine in Rat Plasma: Application to Pharmacokinetic Studies in Rats.

    PubMed

    Ponnayyan Sulochana, Suresh; Ravichandiran, Vishnuvardh; Mullangi, Ramesh; Sukumaran, Sathesh Kumar

    2016-03-01

    A rapid and highly sensitive assay method has been developed and validated for the estimation of tacrine 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 tacrine and phenacetin (internal standard, IS) from rat plasma using ethyl acetate. Chromatographic separation was achieved with 0.2% formic acid : acetonitrile (30 : 70, v/v) at a flow rate of 0.50 mL/min on an Atlantis dC18 column with a total run time of 3.0 min. The MS-MS ion transitions monitored were 199.10 → 171.20 for tacrine and 180.10 → 110.10 for IS. Method validation was performed as per United States Food and Drug Administration (US FDA) guidelines and the results met the acceptance criteria. The lower limit of quantification achieved was 0.008 ng/mL and linearity was observed from 0.008 to 53.4 ng/mL. The intra- and inter-day precision was in the range of 2.76-12.5 and 5.15-12.8%, respectively. This novel method has been applied to a pharmacokinetic study in rats.

  4. Sensitive and precise HPLC method with back-extraction clean-up step for the determination of sildenafil in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Strach, Beata; Wyska, Elżbieta; Pociecha, Krzysztof; Krupa, Anna; Jachowicz, Renata

    2015-10-01

    A sensitive HPLC method was developed and validated for the determination of sildenafil concentrations in rat plasma (200 μL) using a liquid-liquid extraction procedure and paroxetine as an internal standard. In order to eliminate interferences and improve the peak shape, a back-extraction into an acidic solution was utilized. Chromatographic separation was achieved on a cyanopropyl bonded-phase column with a mobile phase composed of 50 m m potassium dihydrogen phosphate buffer (pH 4.5) and acetonitrile (75:25, v/v), pumped at the flow rate of 1 mL/min. A UV detector was set at 230 nm. A calibration curve was constructed within a concentration range from 10 to 1500 ng/mL. The limit of detection was 5 ng/mL. The inter- and intra-day precisions of the assay were in the ranges 2.91-7.33 and 2.61-6.18%, respectively, and the accuracies for inter- and intra-day runs were within 0.14-3.92 and 0.44-2.96%, respectively. The recovery of sildenafil was 85.22 ± 4.54%. Tests confirmed the stability of sildenafil in plasma during three freeze-thaw cycles and during long-term storage at -20 and -80°C for up to 2 months. The proposed method was successfully applied to a pharmacokinetic study in rats.

  5. 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

    2016-09-05

    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.

  6. Application of a high performance liquid chromatography-tandem mass spectrometry method for determination of buflomedil in human plasma for a bioequivalence study.

    PubMed

    Ren, Li; Yang, Chun; Peng, Yan; Li, Fan; Li, Ying-Hui; Zheng, Heng

    2013-09-15

    A rapid, simple and sensitive method based on ultra fast liquid chromatography-tandem spectrometry for the determination of buflomedil in human plasma has been developed and validated using carbamazepine as internal standard. After the precipitation of plasma sample with methanol, the analyte and IS were separated on an Ultimate C18 column (5μm, 2.1mm×50mm, MD, USA) with an isocratic mobile phase composed of acetonitrile and 5mM ammonium acetate in water (60:40, v/v) at a flow rate of 0.25ml/min. The analyte and IS were detected with proton adducts at m/z 308.3-237.1 and m/z 237.2-194.2 in positive ion electrospray ionization and multiple reaction monitoring acquisition mode, respectively. The lower limit of quantification of the method was 23.64ng/ml with a linear dynamic range of 23.64-1182ng/ml for buflomedil. The intra- and inter-batch precisions were less than 5.8%. The developed method was successfully applied to a bioequivalence study of two buflomedil hydrochloride preparations (150mg) in 22 healthy Chinese male volunteers.

  7. Simultaneous quantification of methylene blue and its major metabolite, azure B, in plasma by LC-MS/MS and its application for a pharmacokinetic study.

    PubMed

    Kim, Soo-Jin; Ha, Dong-Jin; Koo, Tae-Sung

    2014-04-01

    A simple and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of methylene blue (MB) and its major metabolite, azure B (AZB), in rat plasma. A simple protein precipitation using acetonitrile was followed by injection of the supernatant on to a Zorbax HILIC Plus column (3.5 µm, 2.1 × 100 mm) with isocratic mobile phase consisting of 5 mM ammonium acetate in 10:90 (v/v) water:methanol at a flow rate of 0.3 mL/min and detection in positive ionization mode. The standard curve was linear over the concentration range from 1 to 1000 ng/mL for MB and AZB with coefficient of determination above 0.9930. The lower limit of quantification was 1 ng/mL using 20 μL of rat plasma sample. The intra- and inter-assay precision and accuracy were <12%. The developed analytical method was successfully applied to the pharmacokinetic study of MB and AZB in rats.

  8. Development and validation of a reversed-phase HPLC method for determination of nitrendipine in rat plasma: application to pharmacokinetic studies.

    PubMed

    Venishetty, Vinay Kumar; Durairaj, Chandrasekar; Sistla, Ramakrishna; Yamsani, Madhusudhan Rao; Diwan, Prakash V

    2007-04-01

    A simple and sensitive method for the determination of nitrendipine in rat plasma was developed using high-performance liquid chromatography (HPLC). The procedure involves extraction of nitrendipine in dichloromethane/sodium hydroxide, followed by reversed phase HPLC using a Waters, Spherisorb ODS2 (250 x 4.6 mm, 5 microm) column and UV detection at 238 nm. The retention times of nitrendipine and internal standard (felodipine) were 5.0 min and 7.5 min, respectively. The calibration curves were linear over the range of 5 ng/mL (lower limit of quantification, LOQ) to 200 ng/mL for nitrendipine. The intra- and inter-day coefficients of variation for all criteria of validation were less than 15% over the linearity range. The sensitivity and precision of the method were within the accepted limits (< 15%) throughout the validation period. The present method was also successfully applied for the study of plasma pharmacokinetics of nitrendipine loaded solid lipid nanoparticles (SLN) in rats.

  9. High-performance liquid chromatographic determination of clindamycin in human plasma or serum: application to the bioequivalency study of clindamycin phosphate injections.

    PubMed

    Liu, C M; Chen, Y K; Yang, T H; Hsieh, S Y; Hung, M H; Lin, E T

    1997-08-29

    This paper presents an assay of clindamycin phosphate injection in human plasma or serum. A 0.5-ml volume of plasma was used with the internal standard, propranolol. The sample was loaded onto a silica extraction column. The column was washed with deionized water and then eluted with methanol. The eluates were evaporated under nitrogen gas. The residue was reconstituted with the mobile phase and injected onto the high-performance liquid chromatographic system: a 5-micron, 25 cm X 4.6 mm I.D. ODS2 column was used with acetonitrile, tetrahydrofuran and 0.05 M phosphate buffer as the mobile phase and with ultraviolet detection at 204 nm. A limit of quantitation of 0.05 microgram/ml was found, with a coefficient of variation of 11.6% (n = 6). The linear range is between 0.05 and 20.00 micrograms/ml and gives a coefficient of determination (r2) or 0.9992. The method has been successfully applied to the bioavailability study of two commercial preparations of clindamycin phosphate injection (300 mg each) in twelve healthy adult male volunteers.

  10. A rapid and sensitive HPLC-APCI-MS/MS method determination of fluticasone in human plasma: application for a bioequivalency study in nasal spray formulations.

    PubMed

    Byrro, Ricardo Martins Duarte; César, Isabela Costa; de Santana e Silva Cardoso, Fabiana Fernandes; Mundim, Iram Moreira; Teixeira, Leonardo de Souza; Bonfim, Ricardo Rodrigues; Gomes, Sandro Antônio; Pianetti, Gerson Antônio

    2012-03-05

    A sensitive method for the determination of fluticasone in plasma was developed using high performance liquid chromatography with tandem mass spectrometric detection, whereas beclomethasone was used as internal standard. The analytes were extracted with a simple liquid-liquid extraction from the plasma samples and separated on an ACE C(18) 50 × 4.6 mm i.d.; 5 μm particle size column with a mobile phase consisting of acetonitrile - 0.01% formic acid (48:52, v/v) at a flow rate of 1 ml/min. Detection was achieved by an Applied Biosystems API 5000 mass spectrometer (LC-MS/MS) set at unit resolution in the multiple reaction monitoring mode. Atmospheric pressure chemical ionization (APCI) was used for ion production. The mean recovery for fluticasone propionate was 85%, with a lower limit of quantification set at 2 pg/mL. The validated analytical method was applied to a bioequivalence study of fluticasone propionate administered by nasal spray formulations in human volunteers.

  11. Sensitive method for the determination of rocilinostat in small volume mouse plasma by LC-MS/MS and its application to a pharmacokinetic study in mice.

    PubMed

    Gupta, Manish; Dixit, Abhishek; Devaraj, V C; Zainuddin, Mohd; Bhamidipati, Ravi Kanth; Hallur, Mahanandeesha S; Dewang, Purushottam; Rajagopal, Sridharan; Rajagopal, Sriram; Mullangi, Ramesh

    2016-07-01

    A highly sensitive, specific and rapid LC-ESI-MS/MS method has been developed and validated for the quantification of rocilinostat in small volume mouse plasma (20 μL) using vorinostat as an internal standard (IS) as per regulatory guidelines. Sample preparation was accomplished through a protein precipitation procedure with acetonitrile. Chromatography was achieved on Prodigy ODS-2 column using a binary gradient using mobile phase A (0.2% formic acid in water) and B (acetonitrile) at a flow rate of 0.38 mL/min. The total chromatographic run time was 4.1 min and the elution of rocilinostat and IS occurred at ~3.2 and 2.9 min, respectively. A linear response function was established in the concentration range of 0.28-1193 ng/mL in mouse plasma. The intra- and inter-day accuracy and precisions were in the ranges of 3.12-8.93 and 6.41-11.6%, respectively. This novel method has been applied to a pharmacokinetic study in mice. Copyright © 2016 John Wiley & Sons, Ltd.

  12. Development and validation of an improved method for the quantitation of sertraline in human plasma using LC-MS-MS and its application to bioequivalence studies.

    PubMed

    Zhang, Mengliang; Gao, Feng; Cui, Xiangyong; Zhang, Yunhui; Sun, Yantong; Gu, Jingkai

    2011-02-01

    A rapid and sensitive LC-MS-MS method for the quantitation of sertraline in human plasma was developed and validated. Sertraline and the internal standard, telmisartan, were cleaned up by protein precipitation from 100 μL of plasma sample, and analyzed on a TC-C18 column (5 μm, 150 × 4.6 mm i.d.) using 70% acetonitrile and 30% 10 mM ammonium acetate (0.1% formic acid) as mobile phase. The method was demonstrated to be linear from 0.1 ng/mL to 50 ng/mL with the lower limit of quantitation of 0.1 ng/mL. Intra- and inter-day precision were below 4.40% and 3.55%. Recoveries of sertraline at low, medium, and high levels were 88.0 ± 2.3%, 88.2 ± 1.9%, and 90.0 ± 2.0%, respectively. The method was successfully applied to a bioequivalence study of sertraline after a single oral administration of 50 mg sertraline hydrochloride tablets.

  13. 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.

  14. Sensitive determination of 20(S)-protopanaxadiol in rat plasma using HPLC-APCI-MS: application of pharmacokinetic study in rats.

    PubMed

    Ren, Hong-Can; Sun, Jian-Guo; Wang, Guang-Ji; A, Ji-Ye; Xie, Hai-Tang; Zha, Wei-Bin; Yan, Bei; Sun, Fen-Zhi; Hao, Hai-Ping; Gu, Sheng-Hua; Sheng, Long-Sheng; Shao, Feng; Shi, Jian; Zhou, Fang

    2008-12-15

    20(S)-Protopanaxadiol (PPD), the main metabolite of protopanoxadiol type ginsenosides (e.g. Rg3 and Rh2), is a very promising anti-cancer drug candidate. To evaluate the pharmacokinetic property of PPD, we reported a reliable, sensitive and simple method utilizing liquid chromatography (HPLC)-atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) to determine PPD. PPD and the internal standard, panoxadiol (PD) were extracted from plasma with acetic ether, separated on a C18 reverse column, and then analyzed by APCI-MS. Targeting fragment ion at m/z 425 for both PPD and PD was monitored in selected-ion monitoring (SIM) mode. PPD can be quantitatively determined at the concentration as low as 1 ng/mL using 200 microL plasma. And the sensitive method showed excellent linearity over a range from 1 to 1000 ng/mL, high recovery, accuracy and precision at the concentrations of 2.5, 100.0 and 1000.0 ng/mL, respectively. The method was successfully applied to pharmacokinetic study of PPD in rats. Pharmacokinetic parameters were calculated and absolute bioavailability of PPD was 36.8+/-12.4%, at least ten times higher than that of Rg3 and Rh2, indicating its good absorption in gastrointestinal tract. It was further suggested that PPD be a promising anti-cancer candidate and probably responsible for the observed pharmacological activity of Rg3 and Rh2.

  15. Quantification of 3-n-butylphthalide in beagle plasma samples by supercritical fluid chromatography with triple quadruple mass spectrometry and its application to an oral bioavailability study.

    PubMed

    Li, Yun; Zhao, Longshan; Li, Xiaoting; Guo, Bei; Zhao, Juanhang; Wang, Xianglin; Zhang, Tianhong

    2015-02-01

    A high-throughput, rapid, sensitive, environmentally friendly, and economical supercritical fluid chromatography with triple quadruple mass spectrometry method was established and validated for the first time to determine a cerebral stroke treatment drug named 3-n-butylphthalide in dog plasma. Plasma samples were prepared by protein precipitation with methanol and the analytes were eluted on an ACQUITY UPC(2TM) HSS-C(18) SB column (3 × 100 mm, 1.8 μm) maintained at 50°C. The mobile phase comprised supercritical carbon dioxide/methanol (90:10, v/v) at a flow rate of 1.5 mL/min, the compensation solvent was methanol at a flow rate of 0.2 mL/min and the total run time was 1.5 min per sample. The detection was carried out on a tandem mass spectrometer with an electrospray ionization source. Calibration curves were linear over the concentration range of 1.02-1021.00 ng/mL (r(2) ≥ 0.993) with the lower limit of quantification of 1.02 ng/mL. The intra- and inter-day precision values were below 15% and the accuracy was from 97.90 to 103.70% at all quality control levels. The method was suitable for a pharmacokinetic study of 3-n-butylphthalide in beagle dogs.

  16. Liquid chromatography/tandem mass spectrometry assay for the simultaneous determination of cefoperazone and sulbactam in plasma and its application to a pharmacokinetic study.

    PubMed

    Zhou, Yingjie; Zhang, Jing; Guo, Beining; Yu, Jicheng; Shi, Yaoguo; Wang, Minggui; Zhang, Yingyuan

    2010-11-15

    A rapid and highly sensitive liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for simultaneous determination of cefoperazone sodium and sulbactam sodium in human plasma was developed. The analytes and internal standard (IS), cefuroxime sodium, were extracted from human plasma via liquid-liquid extraction with ethyl acetate and separated on a Waters Xterra C18 column within 3.5 min. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in selected reaction monitoring (SRM) and negative ion mode. The precursor to product ion transitions monitored for cefoperazone, sulbactam and IS were m/z 644.1→528.0, 232.1→140.0, and 423.0→362.0, respectively. The assay was validated in the linear range of 0.1-20 μg/mL for cefoperazone and 0.02-4 μg/mL for sulbactam. The intra- and inter-day precisions (CV%) were within 8.39% for each analyte. The recoveries were greater than 87.3% for cefoperazone and 87.2% for sulbactam. Each analyte was found to be stable during all sample storage, preparation and analytical procedures. The method was successfully applied in a pharmacokinetic study of Sulperazon injection in six hospital-acquired pneumonia (HAP) patients.

  17. High-throughput determination of carbocysteine in human plasma by liquid chromatography/tandem mass spectrometry: application to a bioequivalence study of two formulations in healthy volunteers.

    PubMed

    Bi, Hui-Chang; Zhao, Li-zi; Zhong, Guo-ping; Zhou, Shufeng; Li, Bo; Deng, Ying; Chen, Xiao; Huang, Min

    2006-01-01

    A rapid and sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to determine carbocysteine in human plasma was developed and fully validated. After methanol-induced protein precipitation of the plasma samples, carbocysteine was subjected to LC/MS/MS analysis using electrospray ionization (ESI). The MS system was operated in the selected ion monitoring (SRM) mode. Chromatographic separation was performed on a Hypurity C18 column (i.d. 2.1 mm x 50 mm, particle size 5 microm). The method had a chromatographic running time of 2.0 min and linear calibration curves over the concentration ranges of 0.1-20 microg/mL for carbocysteine. The lower limit of quantification (LLOQ) of the method was 0.1 microg/mL for carbocysteine. The intra- and inter-day precision was less than 7% for all quality control samples at concentrations of 0.5, 2.0, and 10.0 microg/mL. These results indicate that the method was efficient with a simple preparation procedure and a very short running time (2.0 min) for carbocysteine compared with methods reported in the literature and had high selectivity, acceptable accuracy, precision and sensitivity. The validated LC/MS/MS method has been successfully used to a bioequivalence study of two tablet formulations of carbocysteine in healthy volunteers.

  18. Determination of liquiritigenin by ultra high performance liquid chromatography coupled with triple quadrupole mass spectrometry: Application to a linear pharmacokinetic study of liquiritigenin in rat plasma.

    PubMed

    Gu, Jie; Li, Huan; Pei, Ke; Cai, Hui; Qin, Kunming; Zhang, Xinghai; Zheng, Lijuan; Liu, Xiao; Cai, Yunqing; Cai, Baochang

    2014-09-17

    A simple, sensitive and rapid ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method has been developed and validated for the quantification of liquiritigenin, a promising anti-tumor agent. Liquiritigenin and the internal standard were separated on an Agilent Extend C18 column and eluted with a gradient mobile phase system of acetonitrile and water. The analysis was performed on a negative ionization electrospray mass spectrometer via multiple reaction monitoring (MRM). Transitions of m/z 255.0→119.0 for liquiritigenin and m/z 269.0→117.0 for the IS were monitored. One-step protein precipitation with acetonitrile was used to remove impurities and extract the analytes from plasma. The method had a chromatographic run time of 4.5min and a good linearity in the range of 1-1000ng/mL. The precision (R.S.D.) of intra-day and inter-day ranged from 4.54 to 10.65% and 5.94 to 13.81%, respectively; while the accuracy of intra-day and inter-day ranged from 104.06 to 109.28% and 94.98 to 112.05%. The recovery and stability were also within the acceptable limits. The validated method was applied to a linear pharmacokinetic study of liquiritigenin in rat plasma for the first time.

  19. Simultaneous determination of ipratropium and salbutamol in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Wu, Jingwen; Ding, Cungang; Ge, Qinghua; Li, Zhou; Zhou, Zhen; Zhi, Xiaojin

    2011-11-15

    A novel, sensitive and specific LC-MS/MS method with silica-based solid-phase extraction was developed for simultaneous determination of ipratropium (IPR) and salbutamol (SAL) in rat plasma. Chromatographic separation was achieved on a Shiseido Capcell Pak CR column (SCX:C(18)=1:4, 150 mm × 2.0 mm, 5 μm) with a mobile phase consisting of methanol/water (85:15, v/v) containing 20 mmol/L ammonium formate and 0.1% formic acid at a flow rate of 0.3 mL/min. A tandem mass spectrometric detection with an electrospray ionization (ESI) interface was conducted via multiple reaction monitoring (MRM) under positive ionization mode. This method was validated in terms of specificity, linearity, accuracy (within ±115.4%), intra- and inter-day precision (<11.4%) over the concentration range of 8-1612 pg/mL for IPR and 50-10,000 pg/mL for SAL. In addition, stability and matrix effects of IPR and SAL in plasma were evaluated. This method has been successfully applied to the pharmacokinetic study of compound ipratropium bromide aerosol mainly containing ipratropium bromide (IB) and salbutamol sulphate (SS) after inhalation in rats.

  20. High-throughput LC-MS/MS assay for 6-methoxy-2-naphthylacetic acid, an active metabolite of nabumetone in human plasma and its application to bioequivalence study.

    PubMed

    Patel, Bhavin N; Sharma, Naveen; Sanyal, Mallika; Prasad, Arpana; Shrivastav, Pranav S

    2008-11-01

    A simple, precise and accurate assay for the determination of 6-methoxy-2-naphthylacetic acid (6-MNA), an active metabolite of nabumetone in human plasma, was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The analyte (6-MNA) and propranolol (internal standard, IS) were extracted from 200 microL aliquot of human plasma via solid-phase extraction employing HLB Oasis cartridges and separated on a Discovery HS C18 (50 x 4.6 mm, 5 microm) column. Detection of analyte and IS was done by tandem mass spectrometry with a turbo ion spray interface operating in positive ion and multiple reaction monitoring acquisition mode. The total chromatographic runtime was 3.0 min with retention time for 6-MNA and IS at 1.97 and 1.26 min, respectively. The method was validated over a dynamic linear range of 0.20-60.00 microg/mL for 6-MNA with mean correlation coefficient r > or = 0.9986. The intra-batch and inter-batch precision (%CV) across five validation runs (lower limit of quantiation, low-, medium- and high-quality controls and upper limit of quantitation) was less than 7.5%. The accuracy determined at these levels was within -5.8 to +0.2% in terms of percentage bias. The method was successfully applied for a bioequivalence study of 750 mg nabumetone tablet formulation in 12 healthy Indian male subjects under fasted condition.

  1. Rapid and sensitive determination of levofloxacin in microsamples of human plasma by high-performance liquid chromatography and its application in a pharmacokinetic study.

    PubMed

    Aguilar-Carrasco, José Carlos; Hernández-Pineda, Jessica; Jiménez-Andrade, Juan Miguel; Flores-Murrieta, Francisco Javier; Carrasco-Portugal, Miriam Del Carmen; López-Canales, Jorge Skiold

    2015-03-01

    A rapid, sensitive and simple high-performance liquid chromatographic assay with ultraviolet detection was developed for the quantification of levofloxacin in microsamples (100 μL) of human plasma. The extraction procedure included a protein precipitation technique and a short chromatographic running time (4.5 min). Analyses were carried out on a Symmetry C18 column using a mixture of acetonitrile and 0.01 m potassium dihydrogen aqueous solution (pH 3.4; 14:86 v/v) as mobile phase. The method provided specificity and was linear (r ≥ 0.9992) over the concentration range 0.1-12 µg/mL. The average absolute recovery was 93.59%. The intra- and inter-day coefficients of variation were <6%. Additionally, levofloxacin was stable in all evaluations. The usefulness of this method was demonstrated in a pharmacokinetic study of levofloxacin in healthy adult volunteers. The present method offers two main advantages: (a) the use of microsamples reduces the total volume of blood to be collected from patients; and (b) it provides a good cost-effectiveness ratio. It is concluded that the method is rapid, simple, sensitive, economical and suitable for the determination of levofloxacin in human plasma using a small volume of sample.

  2. Chromatographic/mass spectrometric method for the estimation of itraconazole and its metabolite in human plasma. Application to a bioequivalence study.

    PubMed

    Grabowski, Tomasz; Swierczewska, Anna; Borucka, Beata; Sawicka, Renata; Sasinowska-Motyl, Małgorzata; Gumułka, Stanisław Witold

    2009-01-01

    A HPLC/mass spectrometry method for the estimation of itraconazole (CAS 84625-61-6, ITR) and its active metabolite hydroxyitraconazole (CAS 112559-91-8, HOX) in human plasma was developed. Terconazole (CAS 67915-31-5) was used as an internal standard. The analytical method was fully validated according to FDA and EMEA requirements. The accuracy and precision of the developed method was satisfactory and stability studies showed an acceptable variation (below 15%) of ITR and HOX concentrations when the samples were stored frozen at -75 degrees C for 95 days. The developed method was successfully used for a comparative 2 x 2 period, crossover bioequivalence study of two preparations of ITR (Itrakonazol Genexo 100 mg as the test drug) performed on 36 healthy volunteers.

  3. Studies of particle wake potentials in plasmas

    NASA Astrophysics Data System (ADS)

    Ellis, Ian N.; Graziani, Frank R.; Glosli, James N.; Strozzi, David J.; Surh, Michael P.; Richards, David F.; Decyk, Viktor K.; Mori, Warren B.

    2011-09-01

    A detailed understanding of electron stopping and scattering in plasmas with variable values for the number of particles within a Debye sphere is still not at hand. Presently, there is some disagreement in the literature concerning the proper description of these processes. Theoretical models assume electrostatic (Coulomb force) interactions between particles and neglect magnetic effects. Developing and validating proper descriptions requires studying the processes using first-principle plasma simulations. We are using the particle-particle particle-mesh (PPPM) code ddcMD and the particle-in-cell (PIC) code BEPS to perform these simulations. As a starting point in our study, we examine the wake of a particle passing through a plasma in 3D electrostatic simulations performed with ddcMD and BEPS. In this paper, we compare the wakes observed in these simulations with each other and predictions from collisionless kinetic theory. The relevance of the work to Fast Ignition is discussed.

  4. 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.

  5. 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.

  6. Determination of mianserin in human plasma by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI/MS): application to a bioequivalence study in Chinese volunteers.

    PubMed

    Xu, Ping; Li, Huan-De; Chen, Ben-Mei; Ma, Ning; Yan, Miao; Zhu, Yun-Gui

    2008-08-05

    This study aims to develop a standard protocol for the bioequivalence study of mianserin hydrochloride tablets--a tetracyclic antidepressant drug. For this purpose, a rapid, convenient and selective method using high performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI/MS) has been developed and validated to determine mianserin in human plasma. Mianserin and the internal standard (I.S.), cinnarizine were extracted from plasma by N-hexane:dimethylcarbinol (98:2, v/v) after alkalinized with sodium hydroxide. LC separation was performed on a Thermo Hypersil-Hypurity C18 (5 microm, 150 mm x 2.1 mm) with the mobile phase consisting of 10mM ammonium acetate (pH 3.4)-methanol-acetonitrile (35:50:15, v/v/v) at 0.22 ml/min. The retention time of mianserin and cinnarizine was 3.4 and 2.1 min, respectively. Quadrupole MS detection and quantitation was done by monitoring at m/z 265 [M+H]+ for mianserin and m/z 369 [M+H]+ for cinnarizine. The method was validated over the concentration ranges of 1.0-200.0 ng/ml for mianserin. The recovery was 81.3-84.1%, intra- and inter-day precision of the assay at three concentrations were 9.6-11.4% with accuracy of 97.5-101.2% and the lower limit of quantitation (LLOQ) detection was 1.0 ng/ml for mianserin. The stability of compounds was established in a battery of stability studies, i.e., short-term and long-term storage stability as well as freeze-thaw cycles. This method proved to be suitable for the bioequivalence study of mianserin hydrochloride tablets in healthy human male volunteers.

  7. Development and validation of a high performance liquid chromatography quantification method of levo-tetrahydropalmatine and its metabolites in plasma and brain tissues: application to a pharmacokinetic study.

    PubMed

    Abdallah, Inas A; Huang, Peng; Liu, Jing; Lee, David Y; Liu-Chen, Lee-Yuan; Hassan, Hazem E

    2017-04-01

    Levo-tetrahydropalmatine (l-THP) is an alkaloid isolated from Chinese medicinal herbs of the Corydalis and Stephania genera. It has been used in China for more than 40 years mainly as an analgesic with sedative/hypnotic effects. Despite its extensive use, its metabolism has not been quantitatively studied, nor there a sensitive reliable bioanalytical method for its quantification simultaneously with its metabolites. As such, the objective of this study was to develop and validate a sensitive and selective HPLC method for simultaneous quantification of l-THP and its desmethyl metabolites l-corydalmine (l-CD) and l-corypalmine (l-CP) in rat plasma and brain tissues. Rat plasma and brain samples were processed by liquid-liquid extraction using ethyl acetate. Chromatographic separation was achieved on a reversed-phase Symmetry® C18 column (4.6 × 150 mm, 5 μm) at 25°C. The mobile phase consisted of acetonitrile-methanol-10 mm ammonium phosphate (pH 3) (10:30:60, v/v) and was used at a flow rate of 0.8 mL/min. The column eluent was monitored at excitation and emission wavelengths of 230 and 315 nm, respectively. The calibration curves were linear over the concentration range of 1-10,000 ng/mL. The intra- and interday reproducibility studies demonstrated accuracy and precision within the acceptance criteria of bioanalytical guidelines. The validated HPLC method was successfully applied to analyze samples from a pharmacokinetic study of l-THP in rats. Taken together, the developed method can be applied for bioanalysis of l-THP and its metabolites in rodents and potentially can be transferred for bioanalysis of human samples.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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

  14. Application of a UPLC-MS/MS method for the analysis of alosetron in human plasma to support a bioequivalence study in healthy males and females.

    PubMed

    Chaudhary, Darshan V; Patel, Daxesh P; Shah, Jaivik V; Shah, Priyanka A; Sanyal, Mallika; Shrivastav, Pranav S

    2015-10-01

    A simple, rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed and validated for the determination of alosetron (ALO) in human plasma. The assay method involved solid-phase extraction of ALO and ALO 13C-d3 as internal standard (IS) on a LichroSep DVB-HL (30 mg, 1 cm(3) ) cartridge. The chromatography was performed on an Acquity UPLC BEH C18 (50 × 2.1 mm, 1.7 µm) column using acetonitrile and 2.0 mm ammonium formate, pH 3.0 adjusted with 0.1% formic acid (80:20, v/v) as the mobile phase in an isocratic mode. For quantitative analysis, the multiple reaction monitoring transitions studied were m/z 295.1/201.0 for ALO and m/z 299.1/205.1 for IS in the positive ionization mode. The method was validated over a concentration range of 0.01-10.0 ng/mL for ALO. Post-column infusion experiment showed no positive or negative peaks in the elution range of the analyte and IS after injection of extracted blank plasma. The extent of ion-suppression/enhancement, expressed as IS-normalized matrix factor, varied from 0.96 to 1.04. The assay recovery was within 97-103% for ALO and IS. The method was successfully applied to support a bioequivalence study of 1.0 mg alosetron tablets in 28 healthy Indian male and female subjects.

  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. Simultaneous determination of harpagoside and cinnamic acid in rat plasma by high-performance liquid chromatography: application to a pharmacokinetic study.

    PubMed

    Li, Peifan; Zhang, Yunhui; Xiao, Li; Jin, Xinghua; Yang, Kun

    2007-12-01

    Radix Scrophulariae (xuanshen) is one of the famous Chinese herbal medicines widely used to treat rheumatism, tussis, pharyngalgia, arthritis, constipation, and conjunctival congestion. Harpagoside and cinnamic acid are the main bioactive components of xuanshen. The purpose of this study was to develop an HPLC-UV method for simultaneous determination of harpagoside and cinnamic acid in rat plasma and investigate pharmacokinetic parameters of harpagoside and cinnamic acid after oral administration of xuanshen extract (760 mg kg(-1)). After addition of syringin as internal standard, the analytes were isolated from plasma by liquid-liquid extraction. Separation was achieved on a Kromasil C18 column, and detection was by UV absorption at 272 nm. The described assay was validated in terms of linearity, accuracy, precision, recovery, and limit of quantification according to the FDA validation guidelines. Calibration curves for both analytes were linear with the coefficient of variation (r) for both was greater than 0.999. Accuracy for harpagoside and cinnamic acid ranged from 100.7-103.5% and 96.9-102.9%, respectively, and precision for both analytes were less than 8.5%. The main pharmacokinetic parameters found for harpagoside and cinnamic acid after oral infusion of xuanshen extract were as follows: Cmax 1488.7 +/- 205.9 and 556.8 +/- 94.2 ng mL(-1), Tmax 2.09 +/- 0.31 and (1.48 +/- 0.14 h, AUC(0-24) 10,336.4 +/- 1426.8 and 3653.1 +/- 456.4 ng h mL(-1), AUC(0-infinity) 11,276.8 +/- 1321.4 and 3704.5 +/- 398.8 ng h mL(-1), and t(1/2) 4.9 +/- 1.3 and 2.5 +/- 0.9 h, respectively. These results indicated that the proposed method is simple, selective, and feasible for pharmacokinetic study of radix Scrophulariae extract in rats.

  17. Rapid and Specific Approach for Direct Measurement of Glimepiride in Human Plasma by LC–ESI-MS–MS Employing Automated 96 Well Format: Application to a Bioequivalence Study

    PubMed Central

    Kundlik, M.L.; Zaware, B.H.; Kuchekar, S.R.

    2012-01-01

    A rapid liquid chromatographic method with electrospray ionization tandem mass spectrometric (LC–MS–MS) detection is developed and validated for quantification of glimepiride in heparinized human plasma. Plasma samples, without a drying and reconstitution step, are extracted by solid-phase extraction (SPE) and eluted with 0.9 mL of acetonitrile–methanol (1:1, v/v) containing 0.05% formic acid. The analyte and glimepiride d8 (internal standard, IS) are chromatographed on a C18 column; the mobile phase is acetonitrile–2 mm ammonium formate (88:12, v/v), with the pH adjusted to 3.5 with formic acid, at a flow rate of 0.5 mL/min. The retention times of glimepiride and the IS are 0.93 min, and the runtime is 1.6 min per sample. Selected reaction monitoring of MH+ at m/z 491.20 and 499.26 result in stable fragment ions with m/z 351.80 and 359.96 for glimepiride and the IS, respectively. The response was a linear function of the concentration in the range of 2.0–650.0 ng/mL, with r ≥ 0.9994. The recovery of glimepiride and the IS ranged from 81.91 to 83.36%. The assay has excellent characteristics and has been successfully used for the analysis of glimepiride in healthy human subjects in a bioequivalence study. It was well suited to clinical studies of the drug involving large numbers of samples. PMID:22291058

  18. Simultaneous determination of dextromethorphan, dextrorphan and doxylamine in human plasma by HPLC coupled to electrospray ionization tandem mass spectrometry: application to a pharmacokinetic study.

    PubMed

    Donato, J L; Koizumi, F; Pereira, A S; Mendes, G D; De Nucci, G

    2012-06-15

    In the present study, a fast, sensitive and robust method to quantify dextromethorphan, dextrorphan and doxylamine in human plasma using deuterated internal standards (IS) is described. The analytes and the IS were extracted from plasma by a liquid-liquid extraction (LLE) using diethyl-ether/hexane (80/20, v/v). Extracted samples were analyzed by high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Chromatographic separation was performed by pumping the mobile phase (acetonitrile/water/formic acid (90/9/1, v/v/v) during 4.0min at a flow-rate of 1.5 mL min⁻¹ into a Phenomenex Gemini® C18, 5 μm analytical column (150 × 4.6 mm i.d.). The calibration curve was linear over the range from 0.2 to 200 ng mL⁻¹ for dextromethorphan and doxylamine and 0.05 to 10 ng mL⁻¹ for dextrorphan. The intra-batch precision and accuracy (%CV) of the method ranged from 2.5 to 9.5%, and 88.9 to 105.1%, respectively. Method inter-batch precision (%CV) and accuracy ranged from 6.7 to 10.3%, and 92.2 to 107.1%, respectively. The run-time was for 4 min. The analytical procedure herein described was used to assess the pharmacokinetics of dextromethorphan, dextrorphan and doxylamine in healthy volunteers after a single oral dose of a formulation containing 30 mg of dextromethorphan hydrobromide and 12.5mg of doxylamine succinate. The method has high sensitivity, specificity and allows high throughput analysis required for a pharmacokinetic study.

  19. Development of a LC-MS/MS method for quantification of two pairs of isomeric flavonoid glycosides and other ones in rat plasma: Application to pharmacokinetic studies.

    PubMed

    Zhang, Sixi; Xie, Yang; Wang, Jing; Geng, Yanmei; Zhou, Yu; Sun, Chengxin; Wang, Guangshu

    2017-03-10

    An liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of six flavonoid glycosides including isoorientin (1), orientin (2), 2″-O-β-D-xylopyranosyl isoorientin (3), 2″-O-β-D-xylopyranosyl isovitexin (4), 6-C-L-α-arabipyranosyl vitexin (5), and vitexin (6) in rat plasma using isoquercitrin as the internal standard (IS). Plasma samples were prepared by a one-step protein precipitation with acetonitrile. Chromatographic analysis was carried out on a 25-cm C18 column with a gradient mobile phase consisting of acetonitrile and 0.1% aqueous formic acid. Six analytes and IS were detected through electrospray ionization in negative-ion selection reaction monitoring mode. The mass transitions were as follows: m/z 447.2 → 327.0 for 1, m/z 447.2 → 327.0 for 2, m/z 579.3 → 458.9 for 3, m/z 563.0 → 293.1 for 4, m/z 563.0 → 353.0 for 5, m/z 431.1 → 311.1 for 6, and m/z 463.1 → 300.2 for IS, respectively. Calibration curves exhibited good linearity (r(2)  > 0.9908) over a wide concentration range for all compounds. Intra-day and inter-day precision (RSD%) at four different levels were both less than 14.2% and the accuracy (RE%) ranged from -11.9% to 12.0%. The extraction recoveries of the six components ranged from 88.2% to 103.6%. The validated assay was successfully applied to the pharmacokinetic studies of the six components in male rat plasma after intravenous administration of total flavonoids of Scorzonera austriaca Wild.

  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. Basic Studies in Plasma Physics

    DTIC Science & Technology

    2010-02-17

    ring by Evans, Kafri, Koduvely, and Mukamel, and the weakly asymmetric version was later studied by Clincy, Derrida , and Evans. Here the latter model...Dipole Model, Rev. in Math. Phys., 20, 835-872, 2007 Los Alamos Arxiv:math-ph/0609069 4. B. Derrida , E. Speer and J.L. Lebowitz, Entropy of Open...mat/0612371. 11 14. J.L. Lebowitz, Emergent Phenomena. Physics Journal, 6,1-6, 2007 15. T. Bodineau, B. Derrida and J.L. Lebowitz, Vortices in the

  2. 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.

  3. 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.

  4. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Simultaneous determination of the bioactive components in rat plasma by UPLC-MS/MS and application in pharmacokinetic studies after oral administration of Radix scutellariae extract.

    PubMed

    Tao, Jin-Hua; Xu, Jun; Jiang, Shu; Ling, Yong; Wang, Dong-Geng

    2017-02-16

    A highly sensitive and rapid ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed and validated for simultaneous quantification of the four main bioactive compounds, i.e., baicalin, baicalein, wogonoside and wogonin in rat plasma after oral administration of Radix scutellariae extract. Clarithromycin was used as an internal standard (IS). Plasma samples were processed by protein precipitation with methanol. The separation was performed on an Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 µm) at a flow rate of 0.4 mL/min, using 0.1% formic acid-acetonitrile as mobile phase. The MS/MS ion transit ions monitored were 447.5 → 270.1 for baicalin, 270.1 → 168.1 for baicalein, 461.2 → 284.0 for wogonoside, 284.2 → 168.1 for wogonin and 748.5 → 158.1 for IS. Method validation was performed according to Food and Drug Administration guidelines and the results met the acceptance criteria. The lower limit of quantification (LLOQ) achieved was 1.13 ng/mL for baicalin, 1.23 ng/mL for baicalein, 0.82 ng/mL for wogonoside and 0.36 ng/mL for wogonin, respectively. The calibration curves obtained were linear (r > 0.99) over the concentration range approximately 1-1000 ng/mL. The intra- and inter-day precision was less than 15% and the accuracy was within ±14.7%. After validation, this method was successfully applied to a pharmacokinetic study of Radix scutellariae extract.

  7. Simultaneous determination of rupatadine and its metabolite desloratadine in human plasma by a sensitive LC-MS/MS method: application to the pharmacokinetic study in healthy Chinese volunteers.

    PubMed

    Wen, Jun; Hong, Zhanying; Wu, Yiwen; Wei, Hua; Fan, Guorong; Wu, Yutian

    2009-02-20

    A sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for simultaneous determination of rupatadine and its metabolite desloratadine in human plasma. After the addition of diphenhydramine, the internal standard (IS), plasma samples were extracted with a mixture of methyl tert-butyl ether and n-hexane (1:1, v/v). The analysis was performed on a Ultimate AQ-C18 (4.6mm x 100mm, 5microm) column using a mobile phase consisting of a 80/20 mixture of methanol/water containing 0.0005% formic acid pumped at 0.3mlmin(-1). The analytes and the IS were detected in positive ionization mode and monitoring their precursor-->product ion combinations of m/z 416-->309, 311-->259, and 256-->167, respectively, in multiple reaction monitoring mode. The linear ranges of the assay were 0.1-50 and 0.1-20ngml(-1) for rupatadine and desloratadine, respectively. The lower limits of reliable quantification for both rupatadine and desloratadine were 0.1ngml(-1), which offered high sensitivity and selectivity. The within- and between-run precision was less than 7.2%. The accuracy ranged from -9.2% to +6.4% and -7.2% to +7.2% for rupatadine and desloratadine in quality control samples at three levels, respectively. The method has been successfully applied to a pharmacokinetic study of rupatadine and its major metabolite after oral administration of 10, 20 and 40mg rupatadine tablets to healthy Chinese volunteers.

  8. Simultaneous determination of harpagoside and cinnamic acid in rat plasma by liquid chromatography electrospray ionization mass spectrometry and its application to pharmacokinetic studies.

    PubMed

    Wang, Su-Jun; Ruan, Jin-Xiu; Zhao, Yan-Hong; Zhang, Zhen-Qing

    2008-01-01

    A simple and sensitive method was developed for the simultaneous quantification of harpagoside and cinnamic acid in rat plasma using high-performance liquid chromatography system coupled to a negative ion electrospray mass spectrometric analysis. The plasma sample preparation was a simple deproteinization by the addition of two volumes of acetonitrile. The analytes were separated on an Intersil C8-3 column (2.1 mm i.d.x250 mm, 5 microm) with acetonitrile-5 mm ammonium formate aqueous solution (60:40, v/v) as mobile phase at a flow-rate of 0.2 mL/min. Detection was performed on a quadrupole mass spectrometer equipped with electrospray ionization (ESI) source operated under selected ion monitoring (SIM) mode. [M+HCOO]- at m/z 539 for harpagoside, [M-H]- at m/z 147 for cinnamic acid and [M-H]- at m/z 137 for salylic acid (internal standard) were selected as detecting ions, respectively. The method was validated over the concentration range 7-250 ng/mL for harpagoside and 5-500 ng/mL for cinnamic acid. The lower limits of quantitation for harpagoside and cinnamic acid were 7 and 5 ng/mL, respectively. The intra- and inter-day precisions (RSD%) were within 9.5% and the assay accuracies (RE%) ranged from -5.3 to 3.0% for both analytes. Their average recoveries were greater than 86%. Both analytes were proved to be stable during all sample storage, preparation and analysis procedures. The method was successfully applied to the pharmacokinetic study of harpagoside and cinnamic acid following oral administration of Radix Scrophulariae extract to rats.

  9. Cyproterone acetate quantification in human plasma by high-performance liquid chromatography coupled to atmospheric pressure photoionization tandem mass spectrometry. Application to a comparative pharmacokinetics study.

    PubMed

    Borges, Ney Carter; Mazuqueli, Ana; Moreno, Ronilson Agnaldo; Astigarraga, Rafael Barrientos; Sverdloff, Carlos Eduardo; Galvinas, Paulo Alexandre Rebelo; Sampaio, Maurício Rocha de Magalhães; da Silva, Washington Moreira

    2009-01-01

    A specific, fast and sensitive high performance liquid chromatography (HPLC) coupled to atmospheric pressure photoionization (APPI) tandem mass spectrometric (LC-MS/MS) assay was developed for the determination of cyproterone (CYP) acetate (CAS 427-51-0) in human plasma. The retention times were 3.26 and 2.90 min for CYP acetate and its internal standard (I. S.) finasteride (FIN), respectively. The overall mean recovery, using liquid/liquid extraction, was found to be 109.0, 107.7 and 100.3%, for low, medium and high concentrations, respectively. Calibration curves were linear in the concentration range of 0.1-50.0 ng/ml, and the lower limit of quantification (LLOQ) was 0.1 ng/ml. The LLOQ, 0.1 ng/ml, was sensitive enough for detecting terminal phase concentrations of the drug. Inter-batch precision of the method ranged from 2.2 to 5.55%, while Inter-batch accuracy ranged from 95.5 to 100.0%. Intra-batch precision ranged from 1.8 to 5.6%, while Intra-batch accuracy ranged from 92.0 to 99.4% at concentrations of 0.3 ng/ml, 20.0 and 40.0 ng/ml. The developed method was applied to a bioequivalenc study of CYP acetate in a group of 44 female volunteers at a single oral dose of a 2 mg tablet, in a combination of ethinylestradiol/CYP acetate (0.25/2 mg). The plasma concentration of CYP acetate did not differ significantly after administration of both formulations (test formulation and the reference one). The geometric mean and respective 90% CI of CYP acetate test/reference percent ratios were 90.66% (84.39-97.40%) for Cmax and 96.20% (90.45-102.33%) for AUC0-t.

  10. Development and validation of an LC-ESI-MS/MS method for the simultaneous quantification of naproxen and sumatriptan in human plasma: application to a pharmacokinetic study.

    PubMed

    Brêtas, Juliana Machado; César, Isabela Costa; Brêtas, Camila Machado; Teixeira, Leonardo de Souza; Bellorio, Karini Bruno; Mundim, Iram Moreira; Pianetti, Gerson Antônio

    2016-06-01

    A sensitive and fast liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for the simultaneous quantification of naproxen and sumatriptan in human plasma. A simple liquid-liquid extraction procedure, with a mixture of ethyl acetate, methyl tert-butyl ether, and dichloromethane (4:3:3, v/v), was used for the cleanup of plasma. Naratriptan and aceclofenac were employed as internal standards. The analyses were carried out using an ACE C18 column (50 × 4.6 mm i.d.; particle size 5 μm) and a mobile phase consisting of 2 mM aqueous ammonium acetate with 0.025 % formic acid and methanol (38:62, v/v). A triple-quadrupole mass spectrometer equipped with an electrospray source in the positive mode was set up in the selective reaction monitoring mode to detect the ion transitions m/z 231.67 → m/z 185.07, m/z 296.70 → m/z 157.30, m/z 354.80 → m/z 215.00, and m/z 336.80 → m/z 97.94 for naproxen, sumatriptan, aceclofenac, and naratriptan, respectively. The method was validated and proved to be linear, accurate, precise, and selective over the ranges of 2.5-130 μg mL(-1) for naproxen and 1-50 ng mL(-1) for sumatriptan. The validated method was successfully applied to a pharmacokinetic study with simultaneous administration of naproxen sodium and sumatriptan succinate tablet formulations in healthy volunteers.

  11. Quantification of liensinine in rat plasma using ultra-performance liquid chromatography tandem mass spectrometry and its application to a pharmacokinetic study.

    PubMed

    Lv, Song-Feng; Wang, Xiang-hong; Li, Hong-wei; Zhang, Xiao-lei; Wang, Bo

    2015-06-15

    An ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine liensinine in rat plasma using carbamazepine as the internal standard (IS). Sample preparation was accomplished through a protein precipitation procedure with acetonitrile to 0.1ml plasma sample. The analyte and IS were separated on an Acquity UPLC BEH C18 column (2.1mm×50mm, 1.7μm) with the mobile phase of acetonitrile and 0.1% formic acid in water with gradient elution at a flow rate of 0.40ml/min. The injection volume was 6μl. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) by multiple reactions monitoring (MRM) of the transitions at m/z 611.6→206.2 for liensinine and m/z 237.1→194.2 for IS. The linearity of this method was found to be within the concentration range of 10-1000ng/ml with a lower limit of quantification of 10ng/ml. Only 3.0min was needed for an analytical run. The matrix effect was 93.8-107.4% for liensinine. The intra- and inter-day precision (RSD %) were less than 9.9% and accuracy (RE %) was within ±10.5%. The recovery ranged from 76.2 to 86.8%. Liensinine was sufficiently stable under all relevant analytical conditions. The method was also successfully applied to the pharmacokinetic study of liensinine in rats. The pharmacokinetic parameters were demonstrated as followed: t1/2 was 8.2±3.3h, Cmax was 668.4±156.9ng/ml, and AUC0→∞ was 1802.9±466.4ng/mlh.

  12. Automated determination of venlafaxine in human plasma by on-line SPE-LC-MS/MS. Application to a bioequivalence study.

    PubMed

    Suenaga, Eunice Mayumi; Ifa, Demian R; Cruz, Alessandro Carvalho; Pereira, Renata; Abib, Eduardo; Tominga, Mineko; Nakaie, Clovis Ryuichi

    2009-02-01

    A new automated SPE-LC-ESI-MS/MS method was developed and validated to quantify venlafaxine in human plasma using fluoxetine as an internal standard. The analytes were automatically extracted from plasma by C18 SPE cartridges, separated on a C8 RP column and analyzed by MS in the multiple reaction-monitoring (MRM) mode. The method has a chromatographic run time of 4.0 min and a linear calibration curve over the range of 0.25-200 ng/mL (r >0.997). The between-run precisions, based on the percent RSD for replicate quality controls (0.75; 80, and 200 ng/mL), were < 8.5% for all concentrations. The between-run accuracies, based on the percent relative error, were < 4.0%. This method was successfully employed in a bioequivalence study of two venlafaxine capsule formulations (test formulation from Eurofarma (Brazil) and Efexor XR, reference formulation, from Wyeth-Whitehall, Brazil) in 48 healthy volunteers of both sexes who received a single 150 mg dose of each formulation. More than 3000 samples were analyzed eliminating the analyst's exposure to hazardous organic solvents normally employed in off-line liquid-liquid extractions. The 90% confidence interval (CI) of the individual ratio geometric mean for Test/Reference was 91.6-103.4% for AUC(0-48 h) and 102.2-112.6% for C(max). Since both 90% CI for AUC(0-48 h) and C(max) were included in the 80-125% interval proposed by the US Food and Drug Administration (FDA) and the Brazilian National Health Surveillance Agency (ANVISA), the test formulation was considered bioequivalent to Efexor XR according to both the rate and extent of absorption.

  13. Liquid chromatography-tandem mass spectrometry for the simultaneous quantitation of artemether and lumefantrine in human plasma: application for a pharmacokinetic study.

    PubMed

    César, Isabela Costa; Ribeiro, José Antônio de Aquino; Teixeira, Leonardo de Souza; Bellorio, Karini Bruno; de Abreu, Fernanda Crunivel; Moreira, Josianny Mesquita; Chellini, Paula Rocha; Pianetti, Gerson Antônio

    2011-01-05

    A liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) method for the simultaneous quantitation of artemether and lumefantrine in human plasma was developed and validated. Artesunate was used as an internal standard (IS). The analytes were extracted by a protein precipitation procedure and separated on a reversed-phase Zorbax SB-Ciano column with a mobile phase composed of methanol and 10mM aqueous ammonium acetate containing 0.2% (v/v) acetic acid and 0.1% (v/v) formic acid. Multiple reaction monitoring was performed using the transitions m/z 316 → m/z 267, m/z 530 → m/z 348 and m/z 402 → m/z 267 to quantify artemether, lumefantrine and artesunate, respectively. Calibration curves were constructed over the range of 10-1000 ng/mL for artemether and 10-18,000 ng/mL for lumefantrine. The lower limit of quantitation was 10 ng/mL for both drugs. The mean R.S.D. values for the intra-run precision were 2.6% and 3.0% and for the inter-run precision were 3.6% and 4.6% for artemether and lumefantrine, respectively. The mean accuracy values were 102.0% and 101.2% for artemether and lumefantrine, respectively. No matrix effect was detected in the samples. The validated method was successfully applied to determine the plasma concentrations of artemether and lumefantrine in healthy volunteers, in a one-dose pharmacokinetic study, over the course of 11 days.

  14. A source to deliver mesoscopic particles for laser plasma studies.

    PubMed

    Gopal, R; Kumar, R; Anand, M; Kulkarni, A; Singh, D P; Krishnan, S R; Sharma, V; Krishnamurthy, M

    2017-02-01

    Intense ultrashort laser produced plasmas are a source for high brightness, short burst of X-rays, electrons, and high energy ions. Laser energy absorption and its disbursement strongly depend on the laser parameters and also on the initial size and shape of the target. The ability to change the shape, size, and material composition of the matter that absorbs light is of paramount importance not only from a fundamental physics point of view but also for potentially developing laser plasma sources tailored for specific applications. The idea of preparing mesoscopic particles of desired size/shape and suspending them in vacuum for laser plasma acceleration is a sparsely explored domain. In the following report we outline the development of a delivery mechanism of microparticles into an effusive jet in vacuum for laser plasma studies. We characterise the device in terms of particle density, particle size distribution, and duration of operation under conditions suitable for laser plasma studies. We also present the first results of x-ray emission from micro crystals of boric acid that extends to 100 keV even under relatively mild intensities of 10(16) W/cm(2).

  15. A source to deliver mesoscopic particles for laser plasma studies

    NASA Astrophysics Data System (ADS)

    Gopal, R.; Kumar, R.; Anand, M.; Kulkarni, A.; Singh, D. P.; Krishnan, S. R.; Sharma, V.; Krishnamurthy, M.

    2017-02-01

    Intense ultrashort laser produced plasmas are a source for high brightness, short burst of X-rays, electrons, and high energy ions. Laser energy absorption and its disbursement strongly depend on the laser parameters and also on the initial size and shape of the target. The ability to change the shape, size, and material composition of the matter that absorbs light is of paramount importance not only from a fundamental physics point of view but also for potentially developing laser plasma sources tailored for specific applications. The idea of preparing mesoscopic particles of desired size/shape and suspending them in vacuum for laser plasma acceleration is a sparsely explored domain. In the following report we outline the development of a delivery mechanism of microparticles into an effusive jet in vacuum for laser plasma studies. We characterise the device in terms of particle density, particle size distribution, and duration of operation under conditions suitable for laser plasma studies. We also present the first results of x-ray emission from micro crystals of boric acid that extends to 100 keV even under relatively mild intensities of 1016 W/cm2.

  16. 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

  17. Development and validation of an LC-MS/MS method for the determination of tofogliflozin in plasma and its application to a pharmacokinetic study in rats.

    PubMed

    Kobuchi, Shinji; Matsuno, Megumi; Fukuda, Etsuko; Ito, Yukako; Sakaeda, Toshiyuki

    2016-08-01

    Tofogliflozin is a novel selective inhibitor of sodium-dependent glucose co-transporter-2 (SGLT2) and has been developed for the treatment of patients with type 2 diabetes mellitus. In this study, a highly sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantitation of tofogliflozin in rat plasma was developed and validated. The detection was performed using an API 3200 triple-quadrupole mass spectrometer with selected reaction monitoring (SRM) in the positive electrospray ionization mode. The SRM transitions were m/z=387.1 [M+H](+)→267.1 for tofogliflozin and m/z=451.2 [M+H](+)→71.0 for empagliflozin (internal standard: I.S.). Chromatographic separation was performed on a Quicksorb ODS (2.1mm i.d.×150mm, 5μm size) using isocratic elution with acetonitrile/10mM ammonium acetate (50:50, v/v) as the mobile phase at a flow rate of 0.2mL/min and the total run time was 4.0min. The lower limit of quantification (LLOQ) for tofogliflozin was 0.5ng/mL with sufficient specificity, accuracy, and precision. The validated method was successfully applied to the pharmacokinetic studies of tofogliflozin in rats. This assay method could be a valuable tool for future studies including pharmacokinetic and pharmacodynamic studies of SGLT2 inhibitors.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  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.

  3. Sensitive LC-MS/MS-ESI method for simultaneous determination of montelukast and fexofenadine in human plasma: application to a bioequivalence study.

    PubMed

    Muppavarapu, Rajendraprasad; Guttikar, Swati; Rajappan, Manavalan; Kamarajan, Kannan; Mullangi, Ramesh

    2014-08-01

    A rapid, simple, sensitive and selective LC-MS/MS method was developed and validated for simultaneous quantification of montelukast (MT) and fexofenadine (FF) in human plasma (200 μL) using montelukast-d6 (MT-d6 ) and fexofenadine-d10 (FF-d10 ), respectively as an internal standard (IS) as per the US Food and Drug Administration guidelines. The chromatographic resolution was achieved on a Chromolith RP18e column using an isocratic mobile phase consisting of 20 mm ammonium formate-acetonitrile (20:80, v/v) at flow rate of 1.2 mL/min. The LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. The total run time of analysis was 4 min and elution of MT, FF, MT-d6 and FF-d10 occurred at 2.5, 1.2, 2.4 and 1.2 min, respectively. The standard curve found to be linear in the range 2.00-1000 ng/mL with a coefficient of correlation of ≥0.99 for both the drugs. The intra- and inter-day accuracy and precision values for MT and FF met the acceptance as per FDA guidelines. MT and FF were found to be stable in a battery of stability studies viz., bench-top, auto-sampler and repeated freeze-thaw cycles. The validated assay was applied to an oral bioequivalence study in humans.

  4. 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

    2016-02-05

    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.

  5. 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.

  6. 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.

  7. Study of Volumetrically Heated Ultra-High Energy Density Plasmas

    SciTech Connect

    Rocca, Jorge J.

    2016-10-27

    Heating dense matter to millions of degrees is important for applications, but requires complex and expensive methods. The major goal of the project was to demonstrate using a compact laser the creation of a new ultra-high energy density plasma regime characterized by simultaneous extremely high temperature and high density, and to study it combining experimental measurements and advanced simulations. We have demonstrated that trapping of intense femtosecond laser pulses deep within ordered nanowire arrays can heat near solid density matter into a new ultra hot plasma regime. Extreme electron densities, and temperatures of several tens of million degrees were achieved using laser pulses of only 0.5 J energy from a compact laser. Our x-ray spectra and simulations showed that extremely highly ionized plasma volumes several micrometers in depth are generated by irradiation of gold and Nickel nanowire arrays with femtosecond laser pulses of relativistic intensities. We obtained extraordinarily high degrees of ionization (e.g. we peeled 52 electrons from gold atoms, and up to 26 electrons from nickel atoms). In the process we generated Gigabar pressures only exceeded in the central hot spot of highly compressed thermonuclear fusion plasmas.. The plasma created after the dissolved wires expand, collide, and thermalize, is computed to have a thermal energy density of 0.3 GJ cm-3 and a pressure of 1-2 Gigabar. These are pressures only exceeded in highly compressed thermonuclear fusion plasmas. Scaling these results to higher laser intensities promises to create plasmas with temperatures and pressures exceeding those in the center of the sun.

  8. 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.

  9. Application of Nonlocal Electron Kinetics to Plasma Technologies

    NASA Astrophysics Data System (ADS)

    Kaganovich, Igor D.

    2011-10-01

    Partially ionized plasmas are typically in a highly non-equilibrium thermodynamic state: the electrons are not in equilibrium with the neutral particle species or the ions, and the electrons are also not in equilibrium within their own ensemble, which results in a significant departure of the electron velocity distribution function (EVDF) from a Maxwellian. These non-equilibrium conditions provide considerable freedom to choose optimal plasma parameters for applications, which make gas-discharge plasmas remarkable tools for a variety of plasma applications, including plasma processing, discharge lighting, plasma propulsion, particle beam sources, and nanotechnology. Significant progress in understanding the formation of non-Maxwellian EVDF in the self-consistent electric fields has been one of the major achievements in the low-temperature plasmas during the last decade. This progress was made possible by a synergy between full-scale particle-in-cell simulations, analytical models, and experiments. Specific examples include rf discharges, dc discharges with auxiliary electrodes, Hall thruster discharges. In each example, nonlocal kinetic effects are identified as the main mechanisms responsible for the surprising degree of discharge self-organization. These phenomena include: explosive generation of cold electrons with rf power increase in low-pressure rf discharges; abrupt changes in discharge structure with increased bias voltage on a third electrode in a dc discharge with hot cathode; absence of a steady-state regime in Hall thruster discharges with intense secondary electron emission due to coupling of the sheath properties and the EVDF. In collaboration with Y. Raitses, A.V. Khrabrov, M. Campanell, V. I. Demidov, D. Sydorenko, I. Schweigert, and A. S. Mustafaev. Research supported by the U.S. Department of Energy.

  10. 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)

  11. Simultaneous determination of harmine, harmaline and their metabolites harmol and harmalol in beagle dog plasma by UPLC-ESI-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Zhang, Lei; Teng, Liang; Gong, Can; Liu, Wei; Cheng, Xuemei; Gu, Shenghua; Deng, Zhongping; Wang, Zhengtao; Wang, Changhong

    2013-11-01

    Harmine (HAR) and harmaline (HAL) were metabolized by demethylation to form harmol (HOL) and harmalol (HAM) both in vivo and in vitro. It has been demonstrated tremendous value of HAR, HAL and their metabolites in the therapy of Alzheimer's disease. A rapid, selective and sensitive UPLC-ESI-MS/MS method was firstly developed and validated for the simultaneous determination of HAR, HAL, HOL, and HAM in beagle dog plasma with 9-aminoacridine as the internal standard (IS). After protein precipitation with acetonitrile, the analytes were separated within 4.5 min on an ACQUITY UPLC BEH C18 column with a gradient elution system composed of 0.1% formic acid and acetonitrile at a flow rate of 0.4 ml/min. Detection was performed using multiple reactions monitoring mode under a positive ionization condition. The calibration curves of four analytes showed good linearity (r(2)>0.9959) within the tested concentration ranges. The low limit of quantification for HAR, HAL, HOL, and HAM were all 1.00 ng/ml. The mean accuracy of the analytes was within the range of 94.56-112.23%, the R.S.D. values of intra-day and the inter-day precision were less than 6.26% and 7.51%, respectively. Matrix effects and extraction recoveries of the analytes from the beagle dog plasma were within the range of 94.48-105.77% and 89.07-101.44%, respectively. The validated method was successfully applied to a pharmacokinetic study of HAR, HAL, HOL, and HAM in beagle dogs after intravenous administration of HAR and HAL both of 1.0mg/kg. The main pharmacokinetic parameters of Cmax, Vd, CL, AUC and MRT, except Ke and t1/2 values, showed significant difference between the two parent drug HAR and HAL, respectively (p<0.05-0.001). Because of the different metabolic rate of HAR and HAL in vivo, the two metabolites, HOL and HAM, exhibited unique pharmacokinetic properties.

  12. Simultaneous determination of three sesquiterpene lactones from Herba Inula extract in rat plasma by LC/MS/MS and its application to pharmacokinetic study.

    PubMed

    Yang, Xi; Su, Juan; He, Yajun; Liu, Hui; Li, Haiyun; Zhang, Weidong

    2012-08-15

    A rapid and sensitive liquid chromatography-tandem mass spectrometry method has been developed and validated for the determination of 1-acetoxy-6α-hydroxyeriolanolide, 1β-hydroxyalantolactone and ivangustin from Herba Inula extract in rat plasma. Plasma samples were pretreated by protein precipitation with methanol. Chromatographic separation was accomplished on a TOSOH TSKgel ODS column with mobile phase consisting of methanol and 0.3% formic acid (80:20, v/v). The detection was carried out by multiple-reaction monitoring mode under positive electrospray ionization. The quantification was performed using the transitions of m/z 309.1/185.0 for 1-acetoxy-6α-hydroxyeriolanolide, m/z 249.0/231.1 for 1β-hydroxyalantolactone and ivangustin and m/z 285.0/193.0 for diazepam, respectively. Calibration curves were linear over the concentration range of 4-800 ng/mL for 1-acetoxy-6α-hydroxyeriolanolide, 8-500 ng/mL for 1β-hydroxyalantolactone and ivangustin. The limit of detection (LOD) was 1 ng/mL for 1-acetoxy-6α-hydroxyeriolanolide, 1.6 ng/mL for 1β-hydroxyalantolactone and ivangustin (S/N=3). The intra-day and inter-day precisions (RSD%) for the three compounds were less than 7.8% and 8.6%, and the accuracy (RE%) ranged from -4.6 to 6.8%. The method was successfully applied to pharmacokinetic studies of the three sesquiterpene lactones after oral administration of 300 mg/kg Herba Inula extract to rats, the t(½) of 1-acetoxy-6α-hydroxyeriolanolide, 1β-hydroxyalantolactone and ivangustin was 9.65±1.43, 14.88±0.82 and 13.93±2.74 (h). The AUC((0-t)) of 1-acetoxy-6α-hydroxyeriolanolide, 1β-hydroxyalantolactone and ivangustin was 1102.46±247.04, 808.92±117.53 and 990.35±275.49 (ng h/mL), respectively.

  13. Simultaneous determination of two epimeric furofuran lignans (sesamin and asarinin) of Asarum heterotropoides extract in rat plasma by LC/MS/MS: application to pharmacokinetic study.

    PubMed

    Ma, Yingyan; Xu, Kai; Wang, Shumin; Han, Yaling

    2014-09-01

    A rapid, sensitive and selective liquid chromatography-tandem mass spectrometry was developed to determine two epimeric furofuran lignans (sesamin and asarinin) simultaneously from Asarum heterotropoides extract in rat plasma. Simple protein precipitation with acetonitrile was performed to extract analytes by using alantolactone as an internal standard. Chromatographic separation was achieved using a DIKMA Diamonsil C18 analytical column (4.6 mm × 150 mm, i.d., 5 µm) by isocratically eluting with a mobile phase consisting of methanol/5 mM ammonium acetate/formic acid (75:25:0.1, v/v/v) at a flow rate of 0.8 mL/min. Tandem mass spectrometric detection with an electrospray ionization interface was performed by multiple reaction monitoring in positive ionization mode. This method was validated according to specificity, sensitivity, linearity, intra- and inter-day precision (<10.7%) and accuracy (<2.3%) and recovery and stability in a concentration range of 25.0-15 000 ng/mL for sesamin and 5.00-3 000 ng/mL for asarinin. This method has been successfully applied in a pharmacokinetic study of A. heterotropoides extract containing sesamin and asarinin after this extract was orally administrated in rats.

  14. Liquid chromatography-tandem mass spectrometry simultaneous determination of repaglinide and metformin in human plasma and its application to bioequivalence study.

    PubMed

    Liang, Xiao-Rong; Dai, Xiao-Jian; Zhang, Yi-Fan; Ding, Jue-Fang; Chen, Xiao-Yan; Zhong, Da-Fang

    2013-04-01

    A simple, sensitive, selective, and reproducible liquid chromatography-tandem mass spectrometric method was developed for the simultaneous determination of repaglinide and metformin in human plasma using d5-repaglinide and d6-metformin as internal standards (ISs). After a simple protein precipitation using acetonitrile as the precipitation solvent, both analytes and ISs were separated on a Venusil ASB C 18 (150 mm x 4.6 mm, 5 microm) via gradient elution using acetonitrile--10 mmol x L(-1) ammonium acetate as the mobile phase. A chromatographic total run time of 7.5 min was achieved. Mass spectrometric detection was conducted with atmospheric pressure chemical ionization under positive-ion and multiple-reaction monitoring modes. The method was linear over the 0.2 to 60.0 ng x mL(-1) concentration range for repaglinide and over the 4 to 1 000 ng x mL(-1) range for metformin. For both analytes, the intra- and inter-accuracies and precisions were within the +/- 15% acceptable limit across all concentrations. The validated method was successfully applied to a clinical bioequivalence study.

  15. 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.

  16. Development and Validation of a LC-MS/MS Method for the Simultaneous Estimation of Amlodipine and Valsartan in Human Plasma: Application to a Bioequivalence Study.

    PubMed

    Jangala, Hemanth; Vats, Poonam; Khuroo, Arshad Hussain; Monif, Tausif

    2014-01-01

    A reliable, simple, and robust liquid chromatography-tandem mass spectro-metric (LC-MS/MS) method has been developed and validated that employs solid-phase extraction for the simultaneous estimation of amlodipine and valsartan in human K3EDTA plasma using amlodipine-d4 and valsartan-d9 as internal standards. Chromatographic separation of amlodipine and valsartan was achieved on the Luna C18 (2)100A (150 × 4.6 mm, 5 μm) column using acetonitrile: 5 mM ammonium formate solution (80:20, v/v) as the mobile phase at a flow rate of 0.8 mL/min in isocratic mode. Quantification was achieved using an electrospray ion interface operating in positive mode, under multiple reaction monitoring (MRM) conditions. The assay was found to be linear over the range of 0.302-20.725 ng/mL for amlodipine and 6.062-18060.792 ng/mL for valsartan. The method has shown good reproducibility, as intra- and interday precisions were within 10% and accuracies were within 8% of nominal values for both analytes. The method was successfully applied for the bioequivalence study of amlodipine and valsartan after oral administration of a fixed dose of the combination. Additionally, as required by the current regulatory bodies, incurred sample reanalysis was performed and found to be acceptable.

  17. 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.

  18. Measurement of fexofenadine concentration in micro-sample human plasma by a rapid and sensitive LC-MS/MS employing protein precipitation: application to a clinical pharmacokinetic study.

    PubMed

    Guo, Daqing; Zou, Jianjun; Zhu, Yubing; Lou, Sheng; Fan, Hongwei; Qin, Qun

    2010-03-01

    A simple, rapid and sensitive liquid chromatography/positive ion electro-spray tandem mass spectrometry method (LC-MS/MS) was developed and validated for the quantification of fexofenadine with 100 microL human plasma employing glipizide as internal standard (IS). Protein precipitation was used in the sample preparation procedure. Chromatographic separation was achieved on a reversed-phase C(18 )column (5 microm, 100 x 2.1 mm) with methanol : buffer (containing 10 mmol/L ammonium acetate and 0.1% formic acid; 70 : 30, v/v) as mobile phase. The total chromatographic runtime was approximately 3.0 min with retention time for fexofenadine and IS at approximately 1.9 and 2.1 min, respectively. Detection of fexofenadine and IS was achieved by LC-MS/MS in positive ion mode using 502.1 --> 466.2 and 446.0 --> 321.1 transitions, respectively. The method was proved to be accurate and precise at linearity range of 1-600 ng/mL with a correlation coefficient (r) of > or =0.9976. The validated method was applied to a pharmacokinetic study in human volunteers following oral administration of 60 or 120 mg fexofenadine formulations, successfully.

  19. Development and Validation of a LC-MS/MS Method for the Simultaneous Estimation of Amlodipine and Valsartan in Human Plasma: Application to a Bioequivalence Study

    PubMed Central

    Jangala, Hemanth; Vats, Poonam; Khuroo, Arshad Hussain; Monif, Tausif

    2014-01-01

    Abstract A reliable, simple, and robust liquid chromatography-tandem mass spectro-metric (LC-MS/MS) method has been developed and validated that employs solid-phase extraction for the simultaneous estimation of amlodipine and valsartan in human K3EDTA plasma using amlodipine-d4 and valsartan-d9 as internal standards. Chromatographic separation of amlodipine and valsartan was achieved on the Luna C18 (2)100A (150 × 4.6 mm, 5 μm) column using acetonitrile: 5 mM ammonium formate solution (80:20, v/v) as the mobile phase at a flow rate of 0.8 mL/min in isocratic mode. Quantification was achieved using an electrospray ion interface operating in positive mode, under multiple reaction monitoring (MRM) conditions. The assay was found to be linear over the range of 0.302–20.725 ng/mL for amlodipine and 6.062–18060.792 ng/mL for valsartan. The method has shown good reproducibility, as intra- and interday precisions were within 10% and accuracies were within 8% of nominal values for both analytes. The method was successfully applied for the bioequivalence study of amlodipine and valsartan after oral administration of a fixed dose of the combination. Additionally, as required by the current regulatory bodies, incurred sample reanalysis was performed and found to be acceptable. PMID:25853070

  20. 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.

  1. Simultaneous determination of ambroxol and salbutamol in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry and its application to a pharmacokinetic study.

    PubMed

    Guo, Zhening; Chen, Yangsheng; Ding, Xiaoliang; Huang, Chenrong; Miao, Liyan

    2016-11-01

    A rapid, selective and sensitive liquid chromatography-tandem mass spectrometry assay method was developed for simultaneous determination of ambroxol and salbutamol in human plasma using citalopram hydrobromide as internal standard (IS). The sample was alkalinized with ammonia water (33:67, v/v) and extracted by single liquid-liquid extraction with ethyl acetate. Separation was achieved on Waters Acquity UPLC BEH C18 column using a gradient program at a flow rate of 0.2 mL/min. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the ion transitions m/z 378.9 → 263.6 (ambroxol), m/z 240.2 → 147.7 (salbutamol) and m/z 325.0 → 261.7 (IS). The total analytical run time was relatively short (3 min). Calibration curves were linear in the concentration range of 0.5-100.0 ng/mL for ambroxol and 0.2-20.0 ng/mL for salbutamol, with intra- and inter-run precision (relative standard deviation) <15% and accuracy (relative error) ranging from 97.7 to 112.1% for ambroxol and from 94.5 to 104.1% for salbutamol. The method was successfully applied in a clinical pharmacokinetic study of the compound ambroxol and salbutamol tablets.

  2. 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.

  3. HPLC-MS/MS method for the simultaneous quantification of desmethylmebeverine acid, mebeverine acid and mebeverine alcohol in human plasma along with its application to a pharmacokinetics study.

    PubMed

    Moskaleva, Natalia E; Baranov, Pavel A; Mesonzhnik, Natalia V; Appolonova, Svetlana A

    2017-05-10

    A new simple, rapid and sensitive high pressure liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed and validated for simultaneous analysis of mebeverine metabolites as: mebeverine alcohol (MAL), mebeverine acid (MAC) and desmethylmebeverine acid (DMAC) in human plasma. Sample preparation was performed by protein precipitation following the separation of analytes using an Acquity UPLC BEN C8 column 1.7 mm 2.1×50mm (Waters, USA). (2)H5-desmethylmebeverine acid ((2)H5-DMAC) was used as the internal standard (IS). The proposed method was validated with linear ranges of 0.1-10ng/mL; 1-100ng/mL and 5-1000ng/mL for MAL, MAC and DMAC, respectively. Accuracy for all analytes (%RE), given as deviation between nominal and measured concentration and assay variability (CV) ranged from -4.04% to 4.60% and from 0.31% to 6.43% respectively both for within- and between-run. The overall recoveries for all metabolites were above 85%. The proposed method was used successfully for analysis of real samples from a pharmacokinetics study.

  4. Rapid high performance liquid chromatographic method for determination of clarithromycin in human plasma using amperometric detection: application in pharmacokinetic and bioequivalence studies.

    PubMed

    Foroutan, Seyed Mohsen; Zarghi, Afshin; Shafaati, Alireza; Madadian, Babak; Abolfathi, Farshid

    2013-01-01

    A rapid, sensitive and reproducible HPLC method using amperometric detector was developed and validated for the analysis of clarithromycin in human plasma. The separation was achieved on a monolithic silica column (MZ- C8 125×4.0 mm) using acetonitrile-methanol-potassium dihydrogen phosphate buffer (40:6:54,v/v), with pH of 7.5, as the mobile phase at a flow rate of 1.5 mL/min. The assay enables the measurement of clarithromycin for therapeutic drug monitoring with a minimum quantification limit of 20 ng/mL. The method involves simple, protein precipitation procedure and analytical recovery was complete. The calibration curve was linear over the concentration range of 0.1-6 μg/mL. The coefficients of variation for inter-day and intra-day assay were found to be less than 6%. This method was used in bioequivalency and pharmacokinetic studies of the test (generic) product 2 × 500 mg clarithromycin tablets, with respect to the reference product.

  5. 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.

  6. 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.

  7. Finasteride Quantification in Human Plasma by High-Performance Liquid Chromatography Coupled to Electrospray Ionization Tandem Mass Spectrometry. Application to a Comparative Pharmacokinetics Study.

    PubMed

    Moreno, R A; Moreno, P; Borges, N C; Donato, J L; Oliveira, S E; Borges, N C

    2015-09-01

    A specific, fast and sensitive LC-MS/MS assay was developed for the determination of finasteride in human plasma using betamethsone dipropionate as the internal standard (IS). The limit of quantification was 1.0 ng/ml and the method was linear in the range of 1.0-25.0 ng/ml. The retention times were 0.75 min for finasteride and 0.85 min for IS. Method intra-batch precision and accuracy ranged from 3.6 to 7.1%, and 96.6 to 103.9%, respectively. Inter-batch precision ranged from 2.5 to 3.4%, while Inter-batch accuracy ranged from 100.3 to 103.5%. The analytical method was applied to evaluate the pharmacokinetic and relative bioavailability of 2 different pharmaceutical formulations containing 1.0 mg of finasteride. This study evaluated 38 volunteers in a randomized, 2-period crossover study with 7 days washout period between doses. The geometric mean and respective 90% CI of finasteride test/reference percent ratios were 95.68% (91.2 - 104.6%) for Cmax, 97.5% (92.1-103.3%) for AUC0-t and 98.1 (92.67-103.8) for AUC0-inf. Based on the 90% confidence interval of the individual ratios (test formulation/reference formulation) for Cmax and AUC0-inf, it was concluded that the test formulation is bioequivalent to the reference one with respect to the rate and extent of absorption of finasteride.

  8. Development of a supercritical fluid chromatography-tandem mass spectrometry method for the determination of azacitidine in rat plasma and its application to a bioavailability study.

    PubMed

    Li, Dongpo; Zhang, Tianhong; Kou, Longfa; Zhang, Youxi; Sun, Jin; He, Zhonggui

    2013-12-27

    Azacitidine is widely used for the treatment of myelodysplastic syndromes (MDS) and acute myelogenous leukaemia (AML). The analysis of azacitidine in biological samples is subject to interference by endogenous compounds. Previously reported high-performance liquid chromatography/tandem mass spectrometric (HPLC-MS/MS) bioanalytical assays for azacitidine suffer from expensive sample preparation procedures or from long separation times to achieve the required selectivity. Herein, supercritical fluid chromatography with tandem mass spectrometry (SFC-MS/MS) was explored as a more promising technique for the selective analysis of structure-like or chiral drugs in biological matrices. In this study, a simple, rapid and specific SFC/MS/MS analytical method was developed for the determination of azacitidine levels in rat plasma. Azacitidine was completely separated from the endogenous compounds on an ACQUITY UPLC™ BEH C18 column (100 mm×3.0 mm, 1.7 μm; Waters Corp., Milford, MA, USA) using isocratic elution with CO2/methanol as the mobile phase. The single-run analysis time was as short as 3.5 min. The sample preparation for protein removal was accomplished using a simple methanol precipitation method. The lower limit of quantification (LLOQ) of azacitidine was 20 ng/mL. The intra-day and inter-day precisions were less than 15%, and the relative error (RE) was within ±15% for the medium- and high-concentration quality control (QC) samples and within ±20% for the low-concentration QC samples. Finally, the developed method was successfully applied to a pharmacokinetic study in rats following the intravenous administration of azacitidine.

  9. Terbinafine quantification in human plasma by high-performance liquid chromatography coupled to electrospray tandem mass spectrometry: application to a bioequivalence study.

    PubMed

    de Oliveira, C H; Barrientos-Astigarraga, R E; de Moraes, M O; Bezerra, F A; de Moraes, M E; de Nucci, G

    2001-12-01

    A method based on liquid chromatography with positive ion electrospray ionization and tandem mass spectrometry is described for the determination of terbinafine in human plasma using naftifine as internal standard. The method has a chromatographic run time of 5 minutes and was linear in the range 1.0 to 2000 ng/mL. The limit of quantification was 1.0 ng/mL; the intraday precision was 3.6%, 3.8%, 3.5%, and 4.1%; and the intraday accuracy was -2.7%, 7.7%, 4.8%, and -2.7% for 5.0, 80.0, 250.0, and 1500.0 ng/mL, respectively. The interday precision was 4.9%, 1.7%, 2.4%, and 4.6% and the interday accuracy was 0.3%, 5.8%, 6.5%, and -1.4% for the same concentrations. This method was used in a bioequivalence study of two tablet formulations of terbinafine. Twenty-four healthy volunteers (both sexes) received a single oral dose of terbinafine (250 mg) in an open, randomized, two-period crossover study. The 90% CI of geometric mean ratios between Terbinafina (Medley S/A Indústria Farmacêutica, Campinas, Brazil) and Lamisil (Novartis Biociências S/A, São Paulo, Brazil) were 90.5% to 110.0% for C max, 92.2% to 108.1% for AUC last, and 91.3% to 107.5% for AUC 0-inf. Because the 90% CI for the above-mentioned parameters were included in the 80% to 125% interval proposed by the US FDA, the two formulations were considered bioequivalent in terms of rate and extent of absorption.

  10. 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.

  11. Low voltage drop plasma switch for inverter and modulator applications

    NASA Astrophysics Data System (ADS)

    Goebel, D. M.; Poeschel, R. L.; Schumacher, R. W.

    1993-08-01

    A low forward voltage drop plasma switch has been developed for high-efficiency inverter and modulator applications. The switch, called the HOLLOTRON, is based on a grid-controlled, thermionic hollow-cathode discharge. A low forward voltage drop (10-20 V) is achieved by operating the hollow-cathode discharge in a static gas pressure of xenon. The dense plasma generated in the Ba-oxide dispenser hollow cathode is spread over a relatively large control grid area by a diverging magnetic field superimposed on the discharge. Interruption of the discharge current at high current densities (≳4 A/cm2) over the grid area is achieved by biasing the control grid sufficiently negative with respect to the plasma. The HOLLOTRON switch has demonstrated voltage stand-off of up to 20 kV, switching times of ≤0.3 μs, and pulse repetition frequencies of 20 kHz at 50% duty.

  12. Advanced targets, diagnostics and applications of laser-generated plasmas

    NASA Astrophysics Data System (ADS)

    Torrisi, L.

    2015-04-01

    High-intensity sub-nanosecond-pulsed lasers irradiating thin targets in vacuum permit generation of electrons and ion acceleration and high photon yield emission in non-equilibrium plasmas. At intensities higher than 1015 W/cm2 thin foils can be irradiated in the target-normal sheath acceleration regime driving ion acceleration in the forward direction above 1 MeV per charge state. The distributions of emitted ions in terms of energy, charge state and angular emission are controlled by laser parameters, irradiation conditions, target geometry and composition. Advanced targets can be employed to increase the laser absorption in thin foils and to enhance the energy and the yield of the ion acceleration process. Semiconductor detectors, Thomson parabola spectrometer and streak camera can be employed as online plasma diagnostics to monitor the plasma parameters, shot by shot. Some applications in the field of the multiple ion implantation, hadrontherapy and nuclear physics are reported.

  13. Selective Plasma Etching of Polymeric Substrates for Advanced Applications.

    PubMed

    Puliyalil, Harinarayanan; Cvelbar, Uroš

    2016-06-07

    In today's nanoworld, there is a strong need to manipulate and process materials on an atom-by-atom scale with new tools such as reactive plasma, which in some states enables high selectivity of interaction between plasma species and materials. These interactions first involve preferential interactions with precise bonds in materials and later cause etching. This typically occurs based on material stability, which leads to preferential etching of one material over other. This process is especially interesting for polymeric substrates with increasing complexity and a "zoo" of bonds, which are used in numerous applications. In this comprehensive summary, we encompass the complete selective etching of polymers and polymer matrix micro-/nanocomposites with plasma and unravel the mechanisms behind the scenes, which ultimately leads to the enhancement of surface properties and device performance.

  14. Selective Plasma Etching of Polymeric Substrates for Advanced Applications

    PubMed Central

    Puliyalil, Harinarayanan; Cvelbar, Uroš

    2016-01-01

    In today’s nanoworld, there is a strong need to manipulate and process materials on an atom-by-atom scale with new tools such as reactive plasma, which in some states enables high selectivity of interaction between plasma species and materials. These interactions first involve preferential interactions with precise bonds in materials and later cause etching. This typically occurs based on material stability, which leads to preferential etching of one material over other. This process is especially interesting for polymeric substrates with increasing complexity and a “zoo” of bonds, which are used in numerous applications. In this comprehensive summary, we encompass the complete selective etching of polymers and polymer matrix micro-/nanocomposites with plasma and unravel the mechanisms behind the scenes, which ultimately leads to the enhancement of surface properties and device performance. PMID:28335238

  15. Development and Validation of a Method for Simultaneous Estimation of Metformin and Sitagliptin in Human Plasma by LC-MS-MS and Its Application in a Bioequivalence Study.

    PubMed

    Reddy, Srinivasa; Ahmed, Imran; Ahmad, Iqbal; Mukhopadhyay, Arindam; Thangam, Saral

    2015-10-01

    A simple, sensitive, precise and accurate method for simultaneous estimation of metformin and sitagliptin from human plasma was developed and validated. Samples extracted from plasma using acetonitrile were separated on an SCX column and estimated using API 4000 Mass Spectrometer in the positive atmospheric pressure ionization mode (Turboionspray) by following multiple reaction monitoring transitions for both parent and daughter ions. A linear calibration plot was achieved for both the analytes in the concentration ranges of 10-2,206 ng/mL (for metformin) and 3-800.5 ng/mL (for sitagliptin) prepared in K2EDTA pooled plasma. Mean recovery for metformin was 92% and for sitagliptin was 104.5%. It is a fully validated method and successfully applied for estimation of these drug molecules during biostudies.

  16. 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.

  17. Plasma promoted manufacturing of hydrogen and vehicular applications

    NASA Astrophysics Data System (ADS)

    Bromberg, Leslie

    2003-10-01

    Plasmas can be used for promoting reformation of fuels. Plasma-based reformers developed at MIT use a low temperature, low power, low current electrical discharge to promote partial oxidation conversion of hydrocarbon fuels into hydrogen and CO. The very fuel rich mixture is hard to ignite, and the plasmatron provides a volume-ignition. To minimize erosion and to simplify the power supply, a low current high voltage discharge is used, with wide area electrodes. The plasmatron fuel reformer operates at or slightly above atmospheric pressure. The plasma-based reformer technology provides the advantages of rapid startup and transient response; efficient conversion of the fuel to hydrogen rich gas; compact size; relaxation or elimination of reformer catalyst requirements; and capability to process difficult to reform fuels. These advantages enable use of hydrogen-manufacturing reformation technology in cars using available fuels, such as gasoline and diesel. This plasma-based reformer technology can provide substantial throughputs even without the use of a catalyst. The electrical power consumption of the device is minimized by design and operational characteristics (less than 500 W peak and 200 W average). The product from these plasma reactors is a hydrogen rich mixture that can be used for combustion enhancement and emissions aftertreatment in vehicular applications. By converting a small fraction of the fuel to hydrogen rich gas, in-cylinder combustion can be improved. With minor modification of the engine, use of hydrogen rich gas results in increased fuel efficiency and decreased emissions of smog producing gases. The status of plasma based reformer technology and its application to vehicles will be described.

  18. 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

  19. 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.

  20. A fast and sensitive UHPLC-MS/MS method for the determination of N-butylscopolamine in human plasma: application in a bioequivalence study.

    PubMed

    Suenaga, Eunice Mayumi; Val, Ligia de Cássia; Tominaga, Mineko; Souza Filho, José Homero; Soares, Gidel; Vioto, Monalisa; Nakaie, Clovis Ryuichi

    2017-03-01

    We have developed and validated a fast and sensitive ultra high-performance liquid chromatography with positive ion electrospray ionization tandem mass spectrometry method for determining N-butylscopolamine levels in human plasma using propranolol as an internal standard. The acquisition was set up in the multiple reaction monitoring mode with the transitions m/z 360.3 → 138.0 for N-butylscopolamine and m/z 260.2 → 116.1 for IS. This method uses a liquid-liquid extraction process with dichloromethane. The analyte and IS were chromatographed on a C18 , 50 × 2.1 mm, 1.7 μm column through isocratic elution with acetonitrile-5 mm ammonium acetate (adjusted to pH 3.0 with formic acid). The method was linear in the 1-1000 pg/mL range for N-butylscopolamine and was selective, precise, accurate and robust. The validated method was successfully applied to perform a bioequivalence study of the reference (Buscopan(®) , from Boehringer Ingelheim) and the test sample coated-tablet formulations (from Foundation for Popular Remedy), both containing 10 mg of N-butylscopolamine bromide administered as a single dose. Using 58 healthy volunteers and accounting for the high intra-individual variability confirmed by statistical calculations (38%), the two formulations were considered bioequivalent because the rate and extent of absorption (within 80-125% interval), satisfying international requirements.

  1. Rapid and sensitive LC-MS/MS method for determination of megestrol acetate in human plasma: application to a human pharmacokinetic study.

    PubMed

    Seo, Ji-Hyung; Park, Ji-Sun; Jo, Min-Ho; Park, Mi-Sun; Ryu, Ju-Hee; Cho, Young-Wuk; Shim, Wang-Sup; Noh, Gyu-Jeong; Lee, Kyung-Tae

    2013-04-01

    A rapid, simple and fully validated LC-MS/MS method was developed and validated for the determination of megestrol acetate in human plasma using tolbutamide as an internal standard (IS) after one-step liquid-liquid extraction with methyl-tert-butyl-ether. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring mode by monitoring the transitions m/z 385.5 → 267.1 for megestrol acetate and m/z 271.4 → 155.1 for IS. Chromatographic separation was performed on a YMC Hydrosphere C18 column with an isocratic mobile phase, which consisted of 10 mm ammonium formate buffer (adjusted to pH 5.0 with formic acid)-methanol (60:40, v/v) at a flow rate of 0.4 mL/min. The achieved lower limit of quantitation (LLOQ) was 1 ng/mL (signal-to-noise ratio > 10) and the standard calibration curve for megestrol acetate was linear (r > 0.99) over the studied concentration range (1-2000 ng/mL). The proposed method was fully validated by determining its specificity, linearity, LLOQ, intra- and inter-day precision and accuracy, recovery, matrix effect and stability. The validated LC-MS/MS method was successfully applied for the evaluation of pharmacokinetic parameters of megestrol acetate after oral administration of a single dose 800 mg of megestrol acetate (Megace™) to five healthy Korean male volunteers under fed conditions.

  2. 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

    2016-09-05

    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.

  3. A rapid and simple high-performance liquid chromatography method for the determination of human plasma levofloxacin concentration and its application to bioequivalence studies.

    PubMed

    Zhou, Zhi-Ling; Yang, Min; Yu, Xi-Yong; Peng, Huai-Yan; Shan, Zhi-Xin; Chen, Shu-Zhen; Lin, Qiu-Xiong; Liu, Xiao-Ying; Chen, Tie-Feng; Zhou, Shu-Feng; Lin, Shu-Guang

    2007-10-01

    A high-performance liquid chromatography method with fluorescence detection (HPLC-FLD) for the determination of levofloxacin in human plasma is described. Neutralized with phosphate buffer (pH 7.0), the sample (0.1 mL) was extracted with dichlormethane (1 mL). After voltex-mixing and centrifuged at 3000g for 6 min at 4 degrees C, the upper aqueous layer was aspirated using a micro vacuum pump and the organic layer was directly transferred to a clean test tube without pipetting. The organic solvent was evaporated and the residues were reconstituted with the mobile phase. Levofloxacin and terazosin (internal standard, IS) were chromatographically separated on a C(18) column with a mobile phase containing phosphate buffer (pH 3.0, 10 mm), acetonitrile and triethylamine (76:24:0.076, v/v/v) at a flow rate of 1 mL/min. The analytes were detected using fluorescence detection at an excitation and emission wavelength of 295 and 440 nm, respectively. The linear range of the calibration curves was 0.0521-5.213 microg/mL for levofloxacin with a lower limit of quantitation (0.0521 microg/mL). The retention times of levofloxacin and terazosin were 2.5 and 3.1 min, respectively. Within- and between-run precision was less than 12 and 11%, respectively. Accuracy ranged from -6.3 to 4.5%. The recovery ranged from 86 to 89% at the concentrations of 0.0521, 0.5213 and 5.213 microg/mL. The present HPLC-FLD method is sensitive, efficient and reliable. The method described herein has been successfully used for the pharmacokinetic and bioequivalence studies of a levofloxacin formulation product after oral administration to healthy Chinese volunteers.

  4. Development of a rapid and sensitive UPLC-MS/MS assay for the determination of TM-2 in beagle dog plasma and its application to a pharmacokinetic study.

    PubMed

    Lin, Hongli; Zhao, Yunli; Men, Lei; Yang, Mingjing; Liu, Hui; Shao, Yanjie; Wang, Pei; Tang, Xing; Yu, Zhiguo

    2015-01-01

    A simple and sensitive method based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the determination of TM-2, which was a novel semi-synthetic taxane derivative in beagle dog plasma. Cabazitaxel was chosen as internal standard. Following extraction by methyl tert-butyl ether, the chromatographic separation was achieved on a Thermo Syncronis C18 column (50 × 2.1 mm, 1.7 µm) by gradient elution within a runtime of 3.5 min. The mobile phase consisted of (A) acetonitrile and (B) 2 mmol/L ammonium acetate in water. The detection was accomplished using positive ion electrospray ionization in multiple reaction monitoring mode. The MS/MS ion transitions were monitored at m/z 812.39 → 551.35 for TM-2 and 836.36 → 555.26 for IS, respectively. The method was linear for TM-2 (r = 0.9924) ranging from 2.5 to 1000 ng/mL. The intra-day and inter-day precisions (relative standard deviation) were within 8.0 and 17.6%, respectively, and the accuracy (relative error) was less than 2.3%. The extraction recovery ranged from 83.1 to 97.1%. The reliable method was successfully applied to a pharmacokinetic study of TM-2 in beagle dogs after intravenous drip with different doses of 0.6, 1.2, and 2.4 mg/kg, respectively.

  5. A UPLC/MS/MS method for determination of protosappanin B in rat plasma and its application of a pharmacokinetic and bioavailability study.

    PubMed

    Chen, Wei-Ying; Zhou, Xian-Zhen; Wu, Li-Lan; Wu, Yun-Shan; Wang, Shu-Mei; Liu, Bo; Guo, De-An

    2016-12-14

    Caesalpinia sappan L. is a traditional medicinal plant which is used for promoting blood circulation and cerebral apoplexy therapy in China. Previous reports showed that the extracts of Caesalpinia sappan L. could exert vasorelaxant activity and anti-inflammation activity. Protosappanin B is a major constituent of C. sappan L., and showed several important bioactivities. The separation was achieved by an Acquity UPLC BEH Symmetry Shield RP18 column (1.7 μm, 2.1 × 100 mm) column with the gradient mobile phase consisting of 5 mm ammonium acetate aqueous solution and acetonitrile. Detection was carried out by using negative-ion electrospray tandem mass spectrometry via multiple reaction monitoring. Plasma samples were preprocessed by an extraction with ethyl acetate, and apigenin was used as internal standard. The current UPLC-MS/MS assay was validated for linearity, accuracy, intraday and interday precisions, stability, matrix effects and extraction recovery. After oral and intravenous administration, the main pharmacokinetic parameters were as follows: peak concentrations, 83.5 ± 46.2 and 1329.6 ± 343.6 ng/mL; areas under the concentration-time curve, 161.9 ± 69.7 and 264.9 ± 56.3 μg h/L; and half-lives, 3.4 ± 0.9 and 0.3 ± 0.1 h, respectively. The absolute bioavailability in rats of protosappanin B was 12.2%. The method has been successfully applied to a pharmacokinetic and bioavailability study of protosappanin B in rats.

  6. A simple, rapid and sensitive RP-HPLC-UV method for the simultaneous determination of sorafenib & paclitaxel in plasma and pharmaceutical dosage forms: Application to pharmacokinetic study.

    PubMed

    Khan, Ismail; Iqbal, Zafar; Khan, Abad; Hassan, Muhammad; Nasir, Fazle; Raza, Abida; Ahmad, Lateef; Khan, Amjad; Akhlaq Mughal, Muhammad

    2016-10-15

    A simple, economical, fast, and sensitive RP-HPLC-UV method has been developed for the simultaneous quantification of Sorafenib and paclitaxel in biological samples and formulations using piroxicam as an internal standard. The experimental conditions were optimized and method was validated according to the standard guidelines. The separation of both the analytes and internal standard was achieved on Discovery HS C18 column (250mm×4.6mm, 5μm) using Acetonitrile and TFA (0.025%) in the ratio of (65:35V/V) as the mobile phase in isocratic mode at a flow rate of 1ml/min, with a wavelength of 245nm and at a column oven temperature of 25°Cin a short run time of 12min. The limits of detection (LLOD) were 5 and 10ng/ml while the limits of quantification (LLOQ) were 10 and 15ng/ml for sorafenib and paclitaxel, respectively. Sorafenib, paclitaxel and piroxicam (IS) were extracted from biological samples by applying acetonitrile as a precipitating and extraction solvent. The method is linear in the range of 15-20,000ng/ml for paclitaxel and 10-5000ng/ml for sorafenib, respectively. The method is sensitive and reliable by considering both of its intra-day and inter-day co-efficient of variance. The method was successfully applied for the quantification of the above mentioned drugs in plasma. The developed method will be applied towards sorafenib and paclitaxel pharmacokinetics studies in animal models.

  7. High-Throughput Chiral LC-MS/MS Method Using Overlapping Injection Mode for the Determination of Pantoprazole Enantiomers in Human Plasma with Application to Pharmacokinetic Study.

    PubMed

    Li, Shengni; Jiang, Huafang; Wang, Yiya; Liu, Yinli; Shen, Xiaohang; Liang, Wenzhong; Hong, Zhanying

    2016-07-01

    A sensitive and high-throughput chiral liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of R-pantoprazole and S-pantoprazole in human plasma. Sample extraction was carried out by using ethyl acetate liquid-liquid extraction in 96-well plate format. The separation of pantoprazole enantiomers was performed on a CHIRALCEL OJ-RH column and an overlapping injection mode was used to achieve a run time of 5.0 min/sample. The mobile phase consisted of 1) 10 mM ammonium acetate in methanol: acetonitrile (1:1, v/v) and 2) 20 mM ammonium acetate in water. Isocratic elution was used with flow rate at 500 μL/min. The enantiomers were quantified on a triple-quadrupole mass spectrometer under multiple reaction monitoring (MRM) mode with m/z 382.1/230.0 for pantoprazole and m/z 388.4/230.1 for pantoprazole-d7. Linearity from 20.0 to 5000 ng/mL was established for each enantiomer (r(2)  > 0.99). Extraction recovery ranged from 91.7% to 96.4% for R-pantoprazole and from 92.5% to 96.5% for S-pantoprazole and the IS-normalized matrix factor was 0.98 to 1.07 for R-pantoprazole and S-pantoprazole, respectively. The method was demonstrated with acceptable accuracy, precision, selectivity, and stability and the method was applied to support a pharmacokinetic study of a phase I clinical trial of racemic pantoprazole in healthy Chinese subjects. Chirality 28:569-575, 2016. © 2016 Wiley Periodicals, Inc.

  8. 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.

  9. 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.

  10. Simultaneous determination of seven alkaloids in rat plasma by UFLC-MS/MS and its application to a pharmacokinetic study after oral administration of Cerebralcare Granule.

    PubMed

    Xiaowen, Li; Ling, Tong; Yunfei, Li; Guoxiang, Sun; Dailin, Yang; Herry, Sun

    2016-04-01

    An ultra fast liquid chromatography-tandem mass sepectrometry (UFLC-MS/MS) method was developed for simultaneous determination of seven active alkaloid components (tetrahydropalmatine, corydaline, α-allocryptopine, tetrahydroberberine, tetrahydrocoptisine, tetrahydrocolumbamine and dehydrocorydaline) in rat plasma after oral administration of Cerebralcare Granule. Plasma samples were pretreated by protein precipitation with acetronitrile containing the internal standard diazepam. Chromatographic separation was achieved on a Phenomenex Kinetex C18 column (100×2.1mm, 2.6μm) with gradient elution using mobile phase consisting of acetonitrile -0.1% formic acid in water at a flow rate of 0.3mL/min. The detection was performed on an electrospray ionization triple quadrupole tandem mass spectrometer using multiple reaction monitoring (MRM) with positive ionization mode. The established method was fully validated and proved to be sensitive and specific with lower limits of quantification (LLOQs) all less than 0.0265ng/mL in rat plasma. Good linearities of seven alkaloids were obtained in respective concentration ranges (r>0.9923). The intra- and inter-day precisions were below of 15% for all the seven alkaloids in terms of relative standard deviation (RSD), and the accuracies were ranged from -2.7% to 8.3% in terms of relative error (RE). Extraction recovery, matrix effect and stability were within the required limits in rat plasma. The validated method was successfully applied to investigate the pharmacokinetics of the seven alkaloids in rat plasma after oral administration of Cerebralcare Granule (CG).

  11. Plasma-polymerized methyl methacrylate via intense and highly energetic atmospheric pressure micro-plasma for bio-medical applications

    NASA Astrophysics Data System (ADS)

    Park, Choon-Sang; Ballato, John; Kim, Sung-O.; Clemson University Team

    2013-09-01

    Poly (methyl methacrylate), PMMA, has been widely used as a biocompatible material in bone cement, dental fillings, and many other bio-related applications. Vacuum plasmas and radio frequency (RF) atmospheric plasmas are the most common methods for depositing plasma-derived thin films and nanoparticles. However, the necessary equipment is difficult to operate and maintain as well as being large and expensive. Here, we report the use of a novel intense and highly energetic atmospheric pressure plasma jet array using direct plasma jet-to-jet coupling effects to deposit high quality plasma-polymerized MMA (PPMMA) for bio-medical applications. The newly proposed atmospheric pressure micro-plasma jet array device can generate the intense plasma mode with a strong plasma emission and high plasma particle energy. PPMMA was successfully deposited on a variety of substrates and characterized by SEM, AFM, and FT-IR. The micro-plasma jet is obtained at a sinusoidal voltage with a peak value of 30 kV and frequency of 35 kHz. Argon gas was employed as the discharge gas for plasma generation and its flow rate was in the range of 2230 sccm, Methyl methacrylate (MMA) monomer was vaporized by means of a glass bubbler which was supplied by argon gas with flow rates in the range of 268 sccm from room temperature to 400°C. The deposited PPMMA thin films were flexible, transparent, thin, and strong on metal substrates.

  12. Energetic particle physics with applications in fusion and space plasmas

    SciTech Connect

    Cheng, C.Z.

    1997-05-01

    Energetic particle physics is the study of the effects of energetic particles on collective electromagnetic (EM) instabilities and energetic particle transport in plasmas. Anomalously large energetic particle transport is often caused by low frequency MHD instabilities, which are driven by these energetic particles in the presence of a much denser background of thermal particles. The theory of collective energetic particle phenomena studies complex wave-particle interactions in which particle kinetic physics involving small spatial and fast temporal scales can strongly affect the MHD structure and long-time behavior of plasmas. The difficulty of modeling kinetic-MHD multiscale coupling processes stems from the disparate scales which are traditionally analyzed separately: the macroscale MHD phenomena are studied using the fluid MHD framework, while microscale kinetic phenomena are best described by complicated kinetic theories. The authors have developed a kinetic-MHD model that properly incorporates major particle kinetic effects into the MHD fluid description. For tokamak plasmas a nonvariational kinetic-MHD stability code, the NOVA-K code, has been successfully developed and applied to study problems such as the excitation of fishbone and Toroidal Alfven Eigenmodes (TAE) and the sawtooth stabilization by energetic ions in tokamaks. In space plasmas the authors have employed the kinetic-MHD model to study the energetic particle effects on the ballooning-mirror instability which explains the multisatellite observation of the stability and field-aligned structure of compressional Pc 5 waves in the magnetospheric ring current plasma.

  13. Simultaneous determination of six alkaloid components in rat plasma and its application to pharmacokinetic study of Danmu preparations by an ultra fast liquid chromatography-electrospray ionization-tandem mass spectrometry.

    PubMed

    Yin, Rong; Chen, Jiaquan; Zhao, Yonggang; Jia, Xiaobin; Zhang, Zhiyuan; Feng, Liang; Wang, Hui; Wang, Jingjing; Zhu, Fenxia

    2015-03-01

    Danmu injection and Danmu tablet are two widely used traditional Chinese medicine made of Nauclea officinalis (commonly known as Danmu), in which the alkaloids are the major active substances. In this paper, an ultra fast liquid chromatography-tandem mass spectrometry (UFLC-MS/MS) method was developed for simultaneous determination and the pharmacokinetic characteristics study of six main active alkaloids (naucleamide A-10-O-β-d-glucopyranosid, naucleamide G, pumiloside, 3-epi-pumiloside, strictosamide and vincosamide) of the two above-mentioned Danmu preparations in rat plasma. In the course of the experiment, following sample preparation by protein precipitation with methanol-ethyl acetate (2:1, v/v), the nitrogen-dried extraction was reconstituted in methanol and assayed on a C18 column using a gradient elution program with mobile phase consisting of acetonitrile and water containing 0.1% formic acid. The MS detection was performed in positive ionization mode with selected ion transitions. The established method was fully validated and proved to be sensitive and specific with lower limits of quantification (LLOQs) all less than 0.32ng/mL in rat plasma and matrix effects ranged from 88.87 to 108.27%. Good linearities of six alkaloids were obtained in respective concentration ranges (r(2)>0.995). The average extract recoveries for each compound at three quality control concentration levels were no less than 79.70%, and the precision and accuracy were within the acceptable limits. The validated method was successfully applied to the pharmacokinetic study of six alkaloid components of Danmu injection and tablet in rat plasma. The obtained results may be helpful to reveal the action mechanism and guide the clinical application of Danmu preparations.

  14. Atmospheric-pressure ionization: New approaches and applications for plasmas in contact with liquids

    NASA Astrophysics Data System (ADS)

    Go, D. B.

    2015-10-01

    Historically, gas discharges have been difficult to stabilize at atmospheric pressure, and this has confined them to operation at low pressure under vacuum conditions. However, recent advances in plasma technology have enabled stable high pressure gas discharges up to and even exceeding atmospheric pressure. One significant advantage of operating at atmospheric pressure is that the plasma can be brought into contact with non-conventional substrates, especially soft materials such as plastics, biological tissue, and aqueous solutions. This last example is of prime interest as plasma/liquid interactions have a number of important implications in applications ranging from water purification to plasma medicine. In this paper, recent work studying the impact of electrons in the plasma inducing reactions in aqueous solutions is discussed. These studies include measurements of the bulk solution as the electrons induce long-lived species as well as interfacial measurements directly at the plasma/liquid interface to probe the behaviour of electrons traversing from the plasma into the liquid.

  15. Low-Pressure Plasma Application for the Inactivation of the Seed-borne Pathogen Xanthomonas campestris.

    PubMed

    Nishioka, Terumi; Takai, Yuichiro; Mishima, Tomoko; Kawaradani, Mitsuo; Tanimoto, Hideo; Okada, Kiyotsugu; Misawa, Tatsuya; Kusakari, Shinichi

    2016-01-01

    The aim of this study was to investigate the effect of low-pressure plasma treatment on seed disinfection and the possible mechanisms underlying this effect. Seed-borne disease refers to plant diseases that are transmitted by seeds; seed disinfection is an important technique for prevention of such diseases. In this study, the effectiveness of low-pressure plasma treatment in the inactivation of the seed-borne plant pathogenic bacterium, Xanthomonas campestris, inoculated on cruciferous seeds, was evaluated. The highest inactivation effect was observed when the treatment voltage and argon gas flow rate were 5.5 kV and 0.5 L/min, respectively. The viable cell number of X. campestris was 6.6 log cfu/seed before plasma treatment, and decreased by 3.9 log after 5 min of treatment and by 6.6 log after 40 min. Ethidium monoazide treatment and quantitative real-time PCR results indicated that both the cell membrane and target DNA region were damaged following 5 min of plasma treatment. Although both heat and ozone were generated during the plasma treatment, the contribution of both factors to the inactivation of X. campestris was small by itself in our low-pressure plasma system. Overall, we have shown that our low-pressure plasma system has great applicability to controlling plant pathogenic bacterium contamination of seeds.

  16. 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.

  17. The hairline plasma: An intermittent negative dc-corona discharge at atmospheric pressure for plasma medical applications

    SciTech Connect

    Bussiahn, R.; Brandenburg, R.; Gerling, T.; Kindel, E.; Lange, H.; Lembke, N.; Weltmann, K.-D.; Woedtke, Th. von; Kocher, T.

    2010-04-05

    A cold atmospheric pressure plasma source, called hairline plasma, for biological and medical applications has been developed. Using the physical effect of the negative dc corona discharge, a nanosecond pulsed microplasma has been created. The device produces a very thin (dapprox30 mum) plasma filament with a length of up to 1.5 cm. Due to this geometrical parameters this plasma is particularly suitable for the treatment of microscopic cavities. The low plasma temperature allows to treat the human skin without any heating or painful irritation.

  18. Applications of continuous and orthogonal wavelet transforms to MHD and plasma turbulence

    NASA Astrophysics Data System (ADS)

    Farge, Marie; Schneider, Kai

    2016-10-01

    Wavelet analysis and compression tools are presented and different applications to study MHD and plasma turbulence are illustrated. We use the continuous and the orthogonal wavelet transform to develop several statistical diagnostics based on the wavelet coefficients. We show how to extract coherent structures out of fully developed turbulent flows using wavelet-based denoising and describe multiscale numerical simulation schemes using wavelets. Several examples for analyzing, compressing and computing one, two and three dimensional turbulent MHD or plasma flows are presented. Details can be found in M. Farge and K. Schneider. Wavelet transforms and their applications to MHD and plasma turbulence: A review. Support by the French Research Federation for Fusion Studies within the framework of the European Fusion Development Agreement (EFDA) is thankfully acknowledged.

  19. Simultaneous determination of andrographolide, dehydroandrographolide and neoandrographolide in dog plasma by LC-MS/MS and its application to a dog pharmacokinetic study of Andrographis paniculata tablet.

    PubMed

    Xu, Fang-fang; Fu, Shu-jun; Gu, Sheng-pan; Wang, Zhi-min; Wang, Zhen-zhong; He, Xin; Xiao, Wei

    2015-05-15

    In this study, a sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to simultaneously determinate andrographolide (AP), dehydroandrographolide (DP), and neoandrographolide (NP) in plasma of beagle dogs after oral administration of Andrographis paniculata tablet (A. paniculata). The analytes and bilobalide (internal standard) were separated on an Agilent ZORBAX XDB-C18 column (50mm×2.1mm, 3.5μm) by using gradient elution consisting of methanol and water at a flow rate of 0.50mL/min in 7min. Multiple reaction monitoring (MRM) mode was performed to quantify data under monitoring precursor-product ion transitions of m/z 348.8→286.9, 330.9→107.9, 479.1→160.8 and 325.0→163.0 for AP, DP, NP and internal standard (IS) at negative ion mode, respectively. This method was developed at linearity ranging from 0.50 to 250ng/mL for AP, 1.00 to 500ng/mL for DP and 0.20 to 100ng/mL for NP. The accuracy of each analyte ranged between 94.8% and 107.1% and the precision was within 14.6%. No significant matrix effect was observed. AP, DP and NP were stable during sample storage, preparation and analytic procedures. Furthermore, this method was successfully applied in the investigation of the pharmacokinetic profile of AP, DP and NP in beagle dogs after oral administration of A. paniculata tablet (49.5mg for AP, 7.0mg for DP, 22.0mg for NP). Biological half-life (t1/2) was 2.08±0.99, 3.13±1.19 and 1.07±0.38h for AP, DP and NP, respectively. The areas under curves (AUC0-t) of AP, DP and NP was 494.50±150.64, 26.01±8.72 and 78.78±18.29ngh/mL, respectively.

  20. A validated high-performance liquid chromatographic method for the determination of glibenclamide in human plasma and its application to pharmacokinetic studies.

    PubMed

    Niopas, Ioannis; Daftsios, Athanasios C

    2002-05-15

    Glibenclamide is a potent second generation oral sulfonylurea antidiabetic agent widely used for the treatment of type II diabetes melitus. A rapid, sensitive, precise, accurate and specific HPLC assay for the determination of glibenclamide in human plasma was developed and validated. After addition of flufenamic acid as internal standard, the analytes were isolated from human plasma by liquid-liquid extraction. The method was linear in the 10-400 ng/ml concentration range (r > 0.999). Recovery for glibenclamide was greater than 91.5% and for internal standard was 93.5%. Within-day and between-day precision, expressed as the relative standard deviation (RSD%), ranged from 1.4 to 5.9% and 5.8 to 6.6%, respectively. Assay accuracy was better than 93.4%. The assay was used to estimate the pharmacokinetics of glibenclamide after oral administration of a 5 mg tablet of glibenclamide to 18 healthy volunteers.

  1. Liquid chromatography-mass spectrometric method for the sensitive determination of niflumic acid in human plasma and its application to pharmacokinetic study of talniflumate tablet.

    PubMed

    Park, Eun Ji; Na, Dong Hee; Shin, Young-Hee; Lee, Kang Choon

    2008-12-15

    A sensitive LC-MS method was developed and validated for the determination of niflumic acid (NFA), the active metabolite of the talniflumate formulation, in human plasma. The analyses were performed on C(18) column using acetonitrile-ammonium acetate buffer (pH 5.7, 40:60) as a mobile phase with quadrupole MS detection of NFA at m/z 281 in a negative ion-monitoring mode. Calibration curve was linear in the concentration range of 1-1000ng/mL in human plasma. The higher sensitivity of LC-MS allowed low concentrations of NFA to be determined at initial drug absorption and terminal elimination phases following oral administration of talniflumate tablet.

  2. 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

    2016-06-24

    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%.

  3. Study of Laser Created Metal Vapour Plasmas.

    DTIC Science & Technology

    1981-09-01

    appended as Appendix F. However, in this analysis we had assumed that the resonance state population can be regarded as being in equilibrium with the...value expected on the basis of LTE (local thermo- dynamic equilibrium ) and laser saturation, i.e., N N xlO21e -3 0 4 /k Te’ LTE o ogS(kTe) 3x(kTe )3...1 + g)R 1 / "I , (1) studies,"’ (v) neutral-hydrogen measurements where the rate of stimulated emission in Tokamaks ,?.ls and (vi) fusion-plasma

  4. Numerical study of plasma formation from current carrying conductors

    NASA Astrophysics Data System (ADS)

    Angelova, Milena A.

    The problem of plasma formation from thick conductors driven by intense currents have practical applications in a number of high energy density (HED) fields of interest where complex interaction between conductor surfaces and megagauss magnetic fields is involved. These include: wire-array Z-pinches, magnetically accelerated flier plates, liner acceleration by magnetic field, ultrahigh magnetic field generators, high current fuses, magneto-inertial fusion (MIF), magnetically insulated transmission lines, as well as some astrophysical applications. Recent aluminum rod experiments driven by 1-MA Zebra generator at University of Nevada, Reno (UNR) have provided a benchmark for magnetohydrodynamic (MHD) modeling. The innovative 'hourglass' and 'barbell' load geometries used in the experiments made it possible to distinguish between plasma formation due to Ohmic heating, which can be studied numerically utilizing MHD codes, and plasma formation due to high electric fields, by introducing a large-diameter contact with the electrodes. This prevents nonthermal formation of plasma from being caused early in the current pulse by plasma at contacts, as occurs in simple straight-rod explosion experiments. The UNR megagauss rod experiments were modeled by employing the state-of-the-art radiation-magneto-hydrodynamic code MHRDR. Numerical simulations were performed for a wide range of rods, varying from 100 to 580 microns in radius. A "cold start" initiation was employed in order to create initial parameters close to the experimental conditions. Material properties of aluminum, crucial for such simulations, were modeled employing a set of well tested SESAME format equations-of-state (EOS), ionization, and thermal and electrical conductivity tables. The cold start initiation also allowed observation of the numerical phase transitions of the aluminum rod, from solid to liquid to vapor and finally to low density plasma as it is ohmically heated by the megaampere driving current

  5. Plasma-Based Studies on 4th Generation Light Sources

    SciTech Connect

    Lee, R W; Baldis, H A; Cauble, R C; Landen, O L; Wark, J S; Ng, A; Rose, S J; Lewis, C; Riley, D; Gauthier, J-C; Audebert, P

    2000-11-28

    The construction of a short pulse tunable x-ray laser source will be a watershed for plasma-based and warm dense matter research. The areas we will discuss below can be separated broadly into warn dense matter (WDM) research, laser probing of near solid density plasmas, and laser-plasma spectroscopy of ions in plasmas. The area of WDM refers to that part of the density-temperature phase space where the standard theories of condensed matter physics and/or plasma statistical physics are invalid. Warm dense matter, therefore, defines a region between solids and plasmas, a regime that is found in planetary interiors, cool dense stars, and in every plasma device where one starts from a solid, e.g., laser-solid matter produced plasma as well as all inertial fusion schemes. The study of dense plasmas has been severely hampered by the fact that laser-based methods have been unavailable. The single most useful diagnostic of local plasma conditions, e.g., the temperature (T{sub e}), the density (n{sub e}), and the ionization (Z), has been Thomson scattering. However, due to the fact that visible light will not propagate at electron densities, n{sub e}, {ge} 10{sup 22} cm{sup -3} implies dense plasmas can not be probed. The 4th generation sources, LCLS and Tesla will remove these restrictions. Laser-based plasma spectroscopic techniques have been used with great success to determine the line shapes of atomic transitions in plasmas, study the population kinetics of atomic systems embedded in plasmas, and look at redistribution of radiation. However. the possibilities end for plasmas with n{sub e} {ge} 10{sup 22} since light propagation through the medium is severely altered by the plasma. The entire field of high Z plasma kinetics from laser produced plasma will then be available to study with the tunable source.

  6. 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.

  7. Simultaneous determination of imperatorin and its metabolite xanthotoxol in rat plasma and urine by LC-MS/MS and its application to pharmacokinetic studies.

    PubMed

    Ngo, Lien; Tran, Phuong; Ham, Seong-Ho; Cho, Jung-Hee; Cho, Hea-Young; Lee, Yong-Bok

    2017-02-15

    An accurate, precise, selective, and sensitive liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of imperatorin (IMP) and its metabolite, xanthotoxol (XAN), in rat plasma and urine samples. The analytes, along with psoralen as an internal standard, were determined by multiple reaction monitoring (MRM) operated in the positive electrospray ionization (ESI) mode. Chromatographic separation was performed on an Acquity UPLC BEH C18 column (50mm×2.1mm, 1.7μm) with a mobile phase consisting of 0.1% formic acid solution and 0.1% formic acid in methanol at a flow rate of 0.3mL/min. The run time was 6min per sample and the injection volume was 5μL. The method had a lower limit of quantification (LLOQ) of 0.25ng/mL for IMP in plasma and urine, and 1ng/mL for XAN in urine. The linear calibration curves were fitted over the range of 0.25-1000ng/mL for IMP in plasma, 0.25-1000ng/mL for IMP in urine, and 1-1000ng/mL for XAN in urine, with correlation coefficients greater than 0.995. The inter- and intra-day accuracies (relative error, RE%) were between -8.5% and 3.5%, and the precisions (relative standard deviation, RSD%) were less than 10.0% for all quality control samples (QCs). The analytes were extracted from rat plasma and urine samples using a liquid-liquid extraction method with the extraction recovery in the range of 60.3-79.1%. A good stability of the analytes was observed in all the analysis procedures. The method was successfully validated and applied to determine the pharmacokinetics of IMP in rat plasma and, for the first time, the metabolite kinetics of IMP to XAN in rat urine after IMP administration.

  8. Experimental Study on Plasma Surface Treatment of Capacitors Film

    NASA Astrophysics Data System (ADS)

    Ling, Dai; Ting, Yin; Fuchang, Lin; Fei, Yan

    Plasma surface treatment is an optional way to change the electrical performance of the film capacitors used widely in pulse power application. This paper presents the experimental study of glow discharge plasma treatment to polyphenylene sulfide (PPS) film. By using infrared spectra and scanning electron microscope (SEM), the chemical component and microstructure of material surface has detected to be changed with different treatment strength and various discharge gas. After treatment, the film surface tends to be rougher and some sorts of polar radicals or groups found to be introduced. But there is no obvious change of the electrical strength of the film. At last, theoretical analysis has been carried out with polypropylene film experimental treatment results in author's former work.

  9. Numerical Study of Suspension Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Farrokhpanah, Amirsaman; Coyle, Thomas W.; Mostaghimi, Javad

    2017-01-01

    A numerical study of suspension plasma spraying is presented in the current work. The liquid suspension jet is replaced with a train of droplets containing the suspension particles injected into the plasma flow. Atomization, evaporation, and melting of different components are considered for droplets and particles as they travel toward the substrate. Effect of different parameters on particle conditions during flight and upon impact on the substrate is investigated. Initially, influence of the torch operating conditions such as inlet flow rate and power is studied. Additionally, effect of injector parameters like injection location, flow rate, and angle is examined. The model used in the current study takes high-temperature gradients and non-continuum effects into account. Moreover, the important effect of change in physical properties of suspension droplets as a result of evaporation is included in the model. These mainly include variations in heat transfer properties and viscosity. Utilizing this improved model, several test cases have been considered to better evaluate the effect of different parameters on the quality of particles during flight and upon impact on the substrate.

  10. Studies of Particle Wake Potentials in Plasmas

    NASA Astrophysics Data System (ADS)

    Ellis, Ian; Graziani, Frank; Glosli, James; Strozzi, David; Surh, Michael; Richards, David; Decyk, Viktor; Mori, Warren

    2011-10-01

    Fast Ignition studies require a detailed understanding of electron scattering, stopping, and energy deposition in plasmas with variable values for the number of particles within a Debye sphere. Presently there is disagreement in the literature concerning the proper description of these processes. Developing and validating proper descriptions requires studying the processes using first-principle electrostatic simulations and possibly including magnetic fields. We are using the particle-particle particle-mesh (PPPM) code ddcMD and the particle-in-cell (PIC) code BEPS to perform these simulations. As a starting point in our study, we examine the wake of a particle passing through a plasma in 3D electrostatic simulations performed with ddcMD and with BEPS using various cell sizes. In this poster, we compare the wakes we observe in these simulations with each other and predictions from Vlasov theory. Prepared by LLNL under Contract DE-AC52-07NA27344 and by UCLA under Grant DE-FG52-09NA29552.

  11. 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

  12. 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

  13. 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.

  14. Effects of repetitive platelet-rich plasma application on human tenocyte proliferation.

    PubMed

    Mazzocca, Augustus D; O'Malley, Michael; Beitzel, Knut; McCarthy, Mary Beth R; Chowaniec, David M; Cote, Mark P; Bradley, James P; Romeo, Anthony; Arciero, Robert A

    2015-01-01

    Current clinical application of platelet-rich plasma is showing a trend toward multiple treatments. The goal of this study was to show the benefit of interval platelet-rich plasma application in the healing and recovery of human tenocytes using an in vitro cell model. Eight volunteers (6 men and 2 women) were included in this study (mean±SD age, 31.6±10.9 years). Venous blood was collected from new blood draws at 3 different times. Two blood products were prepared on each day of treatment: platelet-rich plasma derived from a single-spin process (PRPSS) and platelet-rich plasma derived from a double-spin process (PRPDS). The study had 2 limbs: 2-day and 4-day intervals. Cell proliferation, measured as disintegrations per minute, was then examined via a radioactive thymidine assay. In the 2-day-interval group, the difference in disintegrations per minute between days 0 and 2 in the PRPSS group reached statistical significance (P =.006). In the PRPDS group, statistical difference was seen between days 0 and 4 (P=.001) and between days 2 and 4 (P=.030). In the 4-day-interval group, the difference in disintegrations per minute between days 4 and 8 in the PRPSS group reached statistical significance, showing a decrease in cell proliferation (P =.013). In the PRPDS group, a statistical difference was seen between days 0 and 8 (P=.021), also showing a decrease in cell proliferation. The greatest effect of platelet-rich plasma, which has a positive effect on tenocyte proliferation and recovery, is seen on initial application. Its effect is diminished with repetitive application, and this finding leads to questioning of the efficacy of interval platelet-rich plasma dosing.

  15. Development and validation of an enantioselective HPLC-UV method using Chiralpak AD-H to quantify (+)- and (-)-torcetrapib enantiomers in hamster plasma--application to a pharmacokinetic study.

    PubMed

    Trivedi, Ravi Kumar; Dubey, P K; Mullangi, Ramesh; Srinivas, Nuggehally R

    2007-10-01

    stable in a series of stability studies, viz. bench-top (up to 12h), auto-sampler (up to 24h) and freeze/thaw cycles (n=3). Stability of TTB enantiomers was established in hamster plasma for 15 days at -80 degrees C. The application of the assay to a pharmacokinetic study of (-)-TTB in hamsters is described.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. The expansion of a plasma into a vacuum - Basic phenomena and processes and applications to space plasma physics

    NASA Technical Reports Server (NTRS)

    Wright, K. H., Jr.; Stone, N. H.; Samir, U.

    1983-01-01

    In this review attention is called to basic phenomena and physical processes involved in the expansion of a plasma into a vacuum, or the expansion of a plasma into a more tenuous plasma, in particular the fact that upon the expansion, ions are accelerated and reach energies well above their thermal energy. Also, in the process of the expansion a rarefaction wave propagates into the ambient plasma, an ion front moves into the expansion volume, and discontinuities in plasma parameters occur. The physical processes which cause the above phenomena are discussed, and their possible application is suggested for the case of the distribution of ions and electrons (hence plasma potential and electric fields) in the wake region behind artificial and natural obstacles moving supersonically in a rarefied space plasma. To illustrate this, some in situ results are reexamined. Directions for future work in this area via the utilization of the Space Shuttle and laboratory work are also mentioned.

  2. 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.

  3. 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.

  4. Development and validation of an LC-MS/MS method for the determination of SB-505124 in rat plasma: Application to pharmacokinetic study.

    PubMed

    Jiang, Jiayu; Zhang, Yuandong; Zhang, Quan; Li, Yanping; Gong, Tao; Zhang, Zhirong; Ding, Rui; Sun, Xun

    2016-01-05

    A sensitive, selective and rapid liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-MS/MS) method has been developed for the quantification of the novel transforming growth factor-β (TGF-β) inhibitor SB-505124 in rat plasma and then validated. Plasma samples were prepared by simple protein precipitation. Separation was performed on a Diamonsil ODS chromatography column using a mobile phase of acetonitrile and 0.1% (v/v) aqueous formic acid. SB-505124 and the internal standard doxorubicin were detected in the positive ion mode using multiple reaction monitoring of the transitions at m/z 336.2→320.1 and 544.2→397.2, respectively. Calibration curve was linear (r>0.9996) over a concentration range of 10-5000 ng/mL with the lower quantification limit of 10 ng/mL. Both intra- and inter-day precision were within 6.5% and trueness were not more than 3.1%. Extraction recovery and matrix effect were within acceptable limits. Stability tests showed that SB-505124 and the IS remained stable throughout the analytical procedure. The validated LC-MS/MS method was then used to analyze the pharmacokinetics of SB-505124 administered to rats intravenously (8 mg/kg) or orally (10 mg/kg). Oral bioavailability of SB-505124 was calculated as 76.4%, indicating the potential of SB-505124 as an orally administered drug.

  5. Validated liquid chromatography-tandem mass spectrometry method for quantitative determination of dauricine in human plasma and its application to pharmacokinetic study.

    PubMed

    Liu, Xiaoying; Liu, Qian; Wang, Dongmei; Wang, Xueya; Zhang, Peng; Xu, Haiyan; Zhao, Hui; Zhao, Huaiqing

    2010-05-01

    A highly sensitive and selective LC-MS/MS method was developed and validated for the determination of dauricine in human plasma, using protopine as internal standard (IS). The analyte and IS were extracted by liquid-liquid extraction and analyzed by LC-MS/MS. Chromatographic separation was performed on Agilent TC-C(18) column with a mobile phase of methanol-water-glacial acetic acid (60:40:0.8, v/v/v) at a flow rate of 0.7 mL/min. Detection was performed on a triple quadrupole tandem mass spectrum by multiple reaction monitoring (MRM) mode using the electrospray ionization technique in positive mode. The method was linear over the concentration range of 1-200 ng/mL. The lower limit of quantification (LLOQ) was 1 ng/mL in human plasma with acceptable precision and accuracy. The intra- and inter-day precision was less than 5.9% determined from quality control (QC) samples at concentrations of 2.0, 20.0 and 160 ng/mL, and the accuracy was within +/-9.9%. This method was successfully applied for the evaluation of pharmacokinetics of dauricine after oral doses of 100, 300 and 600 mg phenolic alkaloids of menispermum dauricum tablet (PAMDT) to 12 Chinese healthy volunteers.

  6. 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.

  7. Simultaneous quantification of three pyranocoumarins of Peucedanum praeruptorum in rat plasma by liquid chromatography-tandem mass spectrometry: application to pharmacokinetic study.

    PubMed

    Zhou, Guangyu; Chen, Guozhen; Liu, Hongbo

    2015-04-01

    A simple, rapid and robust liquid chromatography-tandem mass spectrometry was established and validated for simultaneous quantifications of three pyranocoumarins (praeruptorin A-C) in rat plasma. Following a single-step liquid-liquid extraction, the analytes were separated on a reversed-phase C18 column with a mobile phase consisting of methanol and 10 mM ammonium acetate solution (70 : 30, v/v) at a constant flow rate of 0.3 mL/min. The linear calibration curves were obtained over the concentration ranges 2.93-1470 ng/mL for praeruptorin A, 1.47-734 ng/mL for praeruptorin B and 2.00-1000 ng/mL for praeruptorin C. The within-batch accuracy was -8.6 to 7.5% for praeruptorin A, -9.5 to 12.0% for praeruptorin B and -10.5 to 12.5% for praeruptorin C, respectively. The between-batch accuracy was -3.5 to 1.4% for praeruptorin A, -8.7 to 3.4% for praeruptorin B and -6.0 to 4.3% for praeruptorin C, respectively. The within-batch and between-batch precisions were ≤13.1 and ≤8.2%, respectively. This method is suitable to simultaneously determine the three pyranocoumarins in plasma and thus to investigate the pharmacokinetics of the pyranocoumarins of Peucedanum praeruptorum in rats.

  8. Simultaneous quantification and semi-quantification of ginkgolic acids and their metabolites in rat plasma by UHPLC-LTQ-Orbitrap-MS and its application to pharmacokinetics study.

    PubMed

    Qian, Yiyun; Zhu, Zhenhua; Duan, Jin-Ao; Guo, Sheng; Shang, Erxin; Tao, Jinhua; Su, Shulan; Guo, Jianming

    2017-01-15

    A highly sensitive method using ultra-high-pressure liquid chromatography coupled with linear ion trap-Orbitrap tandem mass spectrometry (UHPLC-LTQ-Orbitrap-MS) has been developed and validated for the simultaneous identification and quantification of ginkgolic acids and semi-quantification of their metabolites in rat plasma. For the five selected ginkgolic acids, the method was found to be with good linearities (r>0.9991), good intra- and inter-day precisions (RSD<15%), and good accuracies (RE, from -10.33% to 4.92%) as well. Extraction recoveries, matrix effects and stabilities for rat plasm samples were within the required limits. The validated method was successfully applied to investigate the pharmacokinetics of the five ginkgolic acids in rat plasma after oral administration of 3 dosage groups (900mg/kg, 300mg/kg and 100mg/kg). Meanwhile, six metabolites of GA (15:1) and GA (17:1) were identified by comparison of MS data with reported values. The results of validation in terms of linear ranges, precisions and stabilities were established for semi-quantification of metabolites. The curves of relative changes of these metabolites during the metabolic process were constructed by plotting the peak area ratios of metabolites to salicylic acid (internal standard, IS), respectively. Double peaks were observed in all 3 dose groups. Different type of metabolites and different dosage of each metabolite both resulted in different Tmax.

  9. Hollow fiber liquid-phase microextraction for the determination of nimesulide in human plasma and its application to a pharmacokinetic study.

    PubMed

    Yang, W W; Zhang, H F; Jia, Y R; Zhao, T; Zhao, Y L; Tong, L J; Sun, L X

    2011-08-01

    A hollow fiber liquid-phase microextraction (HF-LPME) method in combination with HPLC-UV for the determination of nimesulide in human plasma was developed and validated. A small volume of dihexyl ether contained within a polypropylene hollow fiber was used for the extraction of nimesulide from acidified plasma solutions. Factors affecting the extraction efficiency were optimized and discussed. With HPLC-UV as the end analysis technique, the procedure was validated for nimesulide in the concentration range of 50-5000 ng/mL. The intra- and inter-assay precisions were less than 9.1%, and accuracy was within 3.2%. The lower limit of quantification (LLOQ) was 50 ng/mL. Enrichment factor from 144-fold to 156-fold was achieved at three quality control (QC) concentrations. The mean extraction recovery was greater than 41.2%. This method was successfully applied for the evaluation of pharmacokinetics of nimesulide after single oral doses of 100 mg nimesulide to six healthy Chinese volunteers.

  10. Development and validation of an LC-MS/MS method for the determination of mesalazine in beagle dog plasma and its application to a pharmacokinetic study.

    PubMed

    Qin, Juan; Di, Xin; Wang, Xin; Liu, Youping

    2015-02-01

    A simple, specific and sensitive LC-MS/MS method was developed and validated for the determination of mesalazine in beagle dog plasma. The plasma samples were prepared by protein precipitation, then the separation of the analyte was achieved on a Waters Spherisorb C6 column (150 × 4.6 mm, 5 µm) with a mobile phase consisting of 0.2% formic acid in water-methanol (20:80, v/v). The flow rate was set at 1.0 mL/min with a split ratio of 3:2. Mass spectrometric detection was achieved by a triple-quadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode. Quantitation was performed using selected reaction monitoring of precursor-product ion transitions at m/z 154 → m/z 108 for mesalazine and m/z 285 → m/z 193 for diazepam (internal standard). The linear calibration curve of mesalazine was obtained over the concentration range 50-30,000 ng/mL. The matrix effect of mesalazine was within ±9.8%. The intra- and inter-day precisions were <7.9% and the accuracy (relative error) was within ±3.5%. The validated method was successfully applied to investigate the pharmacokinetics of mesalazine in healthy beagle dogs after rectal administration of mesalazine suppository.

  11. A rapid and sensitive LC/ESI-MS/MS method for quantitative analysis of docetaxel in human plasma and its application to a pharmacokinetic study.

    PubMed

    Yamaguchi, Hiroaki; Fujikawa, Asuka; Ito, Hajime; Tanaka, Nobuaki; Furugen, Ayako; Miyamori, Kazuaki; Takahashi, Natsuko; Ogura, Jiro; Kobayashi, Masaki; Yamada, Takehiro; Mano, Nariyasu; Iseki, Ken

    2012-04-15

    Docetaxel is a taxane family antineoplastic agent widely employed in cancer chemotherapy. We developed a liquid chromatography/tandem mass spectrometry method for the determination of docetaxel in human plasma. Plasma samples were deproteinized by acetonitrile containing internal standard paclitaxel. Chromatographic separation was performed on a TSKgel ODS-100 V 3 μm (50 mm × 2.0 mm i.d.) column using a mobile phase composed of acetonitrile-methanol-water-formic acid (50:5:45:0.1, v/v/v/v). Detection was performed on a triple-quadrupole tandem mass spectrometer with multiple reaction monitoring (MRM) mode via electrospray ionization (ESI) source. This method covered a linearity range of 5-5000 ng/mL with the lower limit of quantification of 5 ng/mL. The intra-day precision and inter-day precision (R.S.D.) of analysis were less than 6.7%, and the accuracy (R.E.) was within ± 9.0% at the concentrations of 5, 20, 200, and 2000 ng/mL. The total run time was 5.0 min. This method was successfully applied for clinical pharmacokinetic investigation.

  12. A validated LC-MS/MS method for rapid determination of brazilin in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Deng, Zhipeng; Wang, Xin; Zhao, Huanxin; Cui, Shuxiang; Yao, Qingqiang; Bai, Hong

    2013-06-01

    Brazilin is a major homoisoflavonoid component isolated from the dried heartwood of traditional Chinese medicine Caesalpinia sappan L., which is a natural red pigment used for histological staining. Herein a sensitive, specific and rapid analytical LC-MS/MS method was established and validated for brazilin in rat plasma. After a simple step of protein precipitation using acetonitrile, plasma samples were analyzed using an LC-MS/MS system. Brazilin and the IS (protosappanin B) were separated on a Diamonsil C18 analytical column (150 × 4.6 mm, 5 µm) using a mixture of water and 10 mm ammonium acetate in methanol (20:80, v/v) as mobile phase at a flow rate of 0.6 mL/min. The method was sensitive with a lower limit of quantitation of 10.0 ng/mL, with good linearity (r(2) ≥ 0.99) over the linear range 10.0-5000 ng/mL. All the validation data, such as accuracy and precision, matrix effect, extraction recovery and stability tests were within the required limits. The assay method was successfully applied to evaluate the pharmacokinetics parameters of brazilin after an oral dose of 100 mg/kg brazilin in rats.

  13. 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.

  14. 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.

  15. Application of a Plasma Powder Welding to engine valves

    SciTech Connect

    Takeuchi, Y.; Nagata, M.

    1985-01-01

    In hardfacing of automobile engine valves made of heat resisting steel such as 21-4N, conventional oxy-acetylene gase welding has been currently conducted manually by well trained operators because of using cast Stellite rods as the filler. In accordance with the strong demands of automatic welding, the authors newly developed an automatically controlled Plasma Powder Welding (PPW) system. This system is characterized by the application of a high thermal density plasma arc as heat source and by using power filler which melts more easily than bar cast rods. Moreover, this PPW system has been applied to the automotive engine valve production line and resulted in the great contribution to manpower saving.

  16. 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.

  17. 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.

  18. Studies on optical emission spectroscopy of nitriding plasma and characterization of nitrided steel

    NASA Astrophysics Data System (ADS)

    Sharma, Manash Kumar

    Plasma in nature is abundant and appears quite beautiful in colour as can be seen in glow of sun and auroras. Plasma produced in laboratories is also quite interesting as a correspondence of the naturally occurring plasmas from a glow discharge to a tokamak. However, plasmas tuned to special conditions have been successfully utilized for material processing, of which, plasma nitriding is one and foremost. The work of the thesis focuses on the setting up of a plasma nitriding system with various diagnostics applied to plasma and plasma treated stainless steels. Emission spectroscopy and probe diagnostics are applied to study the optical and plasma properties whereas austenitic stainless steels are characterized by x-ray diffraction (XRD) and hardness test in order to demonstrate the application of the process. The optical and plasma properties during nitriding are motivating, as these properties will lead to conditions for the formation of surface layer. The formation of iron and chromium nitrides is another important asset of the plasma nitriding process, which is tested by XRD technique, while the surface hardness is tested by hardness test. Optical properties are found from optical emission spectroscopy (OES) in terms of emission intensities and wavelengths. Langmuir probe (LP) is used for finding variations of plasma parameters with respect to process parameters and to make a comparison of plasma parameters with those of optical and discharge parameters. A correlation between OES and material characterization properties is sought in order to make a clear understanding of the process. In Chapter 1, introduction to plasma, the possible applications with relevance to plasma nitriding and spectroscopy are described. Plasma nitriding (termed in the title as nitriding plasma for convenience) has emerged as a powerful tool in modifying surface properties of a material without affecting the bulk properties. The various advantages over a conventional gas nitriding

  19. 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.

  20. 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.

  1. 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.

  2. Application of Langmuir Probe for Study of Recombination of D3+ Ions with Electrons in He-Ar-D2 Stationary and Flowing Afterglow Plasma

    NASA Astrophysics Data System (ADS)

    Tichy, M.; Poterya, V.; Plasil, R.; Pysanenko, A.; Kudrna, P.; Novotny, O.; Zakouril, P.; Glosik, J.

    2003-06-01

    We report measurements of the rate coefficient for recombination of D3+ and D5+ with electrons in He-Ar-D2 plasma. Two afterglow experiments, flowing afterglow and stationary afterglow were used to cover large extent of pressures of He buffer gas (2-10 Torr) and large extent of partial number densities of D2 (5×1010-3×1015cm-3). Langmuir probes and mass spectrometers were used to monitor decay of the plasma during the afterglow. The observed rate coefficient is dependent on the deuterium number density indicating that third-body-assisted recombination is efficient and significantly contributes to recombination when sufficient number density of deuterium is present. At low D2 number densities the ions D3+ dominate the ion composition and electron density decay is controlled by recombination of D3+ with recombination rate coefficient α(D3+). At higher D2 number densities and lower temperatures D5+ are formed and electron density decay is controlled by recombination of D5+ ions with recombination rate coefficient α(D5+). The overall effective recombination rate coefficient αeff as a function of D2 number density was measured and from this dependence the rates α(D3+) and α(D5+) at several temperatures were determined. Obtained pressure dependencies are in good agreement with thermodynamic data. When the deuterium number density is decreased down to 5×1010cm-3, the rate coefficient also decreases to αeff ˜4×10-9 cm3s-1. These data indicate that the binary dissociative recombination of D3+ is very slow with αDR <4×10-9 cm3s-1. The observation of an additional de-ionization process proceeding via formation of D5+ and its recombination is also reported.

  3. Plasma-Assisted Combustion Studies at AFRL

    DTIC Science & Technology

    2009-11-04

    important for lean, gas-turbine ( powerplant ) operation Might one also mitigate/influence acoustic fluctuations? Potential for uniform performance with...Thermometry with pulsed -W Source No -W Pulsed -W Direct coupled plasma torch: flame OH vs. - wave power: Plasma-assisted Ignition Cathey, Gundersen, Wang...Determine physical mechanism, primarily for transient plasma ignition  What is role of humidity: XH2O affects detonation wave speed in PDE but not

  4. 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.

  5. 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

  6. Fundamental Mechanisms, Predictive Modeling, and Novel Aerospace Applications of Plasma Assisted Combustion

    DTIC Science & Technology

    2011-11-01

    Fundamental Mechanisms, Predictive Modeling, and Novel Aerospace Applications of Plasma Assisted Combustion Yiguang Ju AFOSR MURI Review Meeting...SUBTITLE Fundamental Mechanisms, Predictive Modeling, and Novel Aerospace Applications of Plasma Assisted Combustion 5a. CONTRACT NUMBER 5b. GRANT...stabilization • Combustion completion F135 engine: (F35, 2011) Mach 6-8 Ignition instability Plasma assisted combustion Plasma Ions/electrons Excited species

  7. Swirling Annular Flow Experiments with Application to Plasma Torches

    NASA Astrophysics Data System (ADS)

    Fisher, L. E.; Settles, G. S.; Miller, J. D.

    2001-11-01

    Swirling flows have many applications such as combustors and cyclone separators. Here, a turbulent swirling annular cold-flow experiment is conducted in order to gain insight into conditions within a plasma cutting torch. Compressed air is forced through six circumferentially-spaced holes that impart tangential velocity to the flow at the annulus inlet. The flow subsequently traverses an annulus of L/D1 =1.8 before exiting through a sonic nozzle. The annulus (created by a cylindrical cathode in the center of the actual plasma torch) is viewable through an outer plexiglass cylinder in our 11:1 scaled-up cold-flow apparatus. Surface oil-flow visualization and laser sheet imaging are employed to investigate the annular flowfield at a Reynolds number of about 1000 based on gap width D2-D1. Results of these experiments, leading to a physical model of the flowfield, are shown. These results are helpful in understanding and improving the fluid-dynamic behavior of actual plasma torches, widely used to cut sheet metal in manufacturing. Supported by Hypertherm Inc.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. ICRH antenna coupling physics and optimum plasma edge density profile. Application to ITER

    NASA Astrophysics Data System (ADS)

    Messiaen, A.; Weynants, R.

    2011-08-01

    The performance of an ICRH system depends on the coupling capabilities of the antenna to the inhomogeneous plasma profile in front of it. The aim of this study is to understand the key physics phenomena contributing to the coupling. It is shown that the following plasma density profile characteristics are decisive: (i) distance between the antenna and the wave cutoff density, (ii) position of an optimum density with respect to the cutoff one and (iii) the density gradient leading from this optimum density to the plasma bulk. At each step of the analysis approximate relations are derived and the loading due to the plasma is compared with that of an isotropic dielectric medium in view of the application for modelling or dummy load testing. Examples are taken starting from the case of the projected ITER antenna array with its different phasing cases in front of the plasma edge profile used in the conceptual design phase. It is shown that, for the same antenna-cutoff distance, slight profile modifications can lead to substantial coupling and therefore power capability variations. Stronger profile modifications and some critically shaped resonant edge profiles are also analysed. The usefulness of a dielectric medium to simulate plasma loading is discussed in an appendix.

  13. Plasma treatment for improving cell biocompatibility of a biodegradable polymer scaffold for vascular graft applications.

    PubMed

    Valence, Sarra de; Tille, Jean-Christophe; Chaabane, Chiraz; Gurny, Robert; Bochaton-Piallat, Marie-Luce; Walpoth, Beat H; Möller, Michael

    2013-09-01

    Biodegradable synthetic scaffolds are being evaluated by many groups for the application of vascular tissue engineering. In addition to the choice of the material and the structure of the scaffold, tailoring the surface properties can have an important effect on promoting adequate tissue regeneration. The objective of this study was to evaluate the effect of an increased hydrophilicity of a polycaprolactone vascular graft by treatment with a cold air plasma. To this end, treated and untreated scaffolds were characterized, evaluated in vitro with smooth muscle cells, and implanted in vivo in the rat model for 3 weeks, both in the subcutaneous location and as an aortic replacement. The plasma treatment significantly increased the hydrophilicity of the scaffold, with complete wetting after a treatment of 60 sec, but did not change fiber morphology or mechanical properties. Smooth muscle cells cultured on plasma treated patches adopt a spread out morphology compared to a small, rounded morphology on untreated patches. Subcutaneous implantation revealed a low foreign body reaction for both types of scaffolds and a more extended and dense cellular infiltrate in the plasma treated scaffolds. In the vascular position, the plasma treatment induced a better cellularization of the graft wall, while it did not affect endothelialization rate or intimal hyperplasia. Plasma treatment is therefore an accessible tool to easily increase the biocompatibility of a scaffold and accelerate tissue regeneration without compromising mechanical strength, which are valuable advantages for vascular tissue engineering.

  14. 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

  15. Fundamental Study of Nuclear Pumped Laser Plasmas.

    DTIC Science & Technology

    1980-12-23

    rate of up to 2pps. The plasma cell/gas- handling system obtains base pressures of 5xlO 8 Torr prior to high purity gas fill. The plasma cell is...synchronization problems, etc.). Due to the exceptional reproducibility of e-beam characteristics, todate , only prefire has caused data rejection. IV. Recent

  16. 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.

  17. 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

  18. Studies on plasma profiles and its effect on dust charging in hydrogen plasma

    NASA Astrophysics Data System (ADS)

    Kakati, B.; Kausik, S. S.; Saikia, B. K.; Bandyopadhay, M.

    2010-02-01

    Plasma profiles and its influence on dust charging are studied in hydrogen plasma. The plasma is produced in a high vacuum device by a hot cathode discharge method and is confined by a cusped magnetic field cage. A cylindrical Espion advanced Langmuir probe having 0.15 mm diameter and 10.0 mm length is used to study the plasma parameters for various discharge conditions. Optimum operational discharge parameters in terms of charging of the dust grains are studied. The charge on the surface of the dust particle is calculated from the capacitance model and the current by the dust grains is measured by the combination of a Faraday cup and an electrometer. Unlike our previous experiments in which dust grains were produced in-situ, here a dust dropper is used to drop the dust particles into the plasma.

  19. Determination of a natural DNMT1 inhibitor, peperomin E, in rat plasma by UFLC-MS/MS and method application in a pharmacokinetic study.

    PubMed

    Wang, Xin-Zhi; Wen, Hong-Mei; Chai, Chuan; Zhang, Wen-Ying; Gao, Ming; Liu, Rui; Wu, Hao; Liang, Jing-Yu

    2017-01-06

    Peperomin E (PepE), a naturally occurring secolignan isolated from Peperomia dindygulensis, has drawn much attention recently owing to its anticancer and DNA methyltransferase 1 (DNMT1) inhibitory activity. Here, a simple and sensitive ultra-fast liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of PepE in rat plasma for the first time. Samples were prepared by simple protein precipitation. Separation was performed on an XBridge™ C18 column using a mobile phase of acetonitrile and 0.1% (v/v) aqueous formic acid. PepE and the internal standard arctigenin were detected in a positive-ion mode using multiple reaction monitoring of the transitions at m/z 413.2 → 261.0 and 373.2 → 137.2, respectively. The calibration curve for PepE was linear over the range of concentrations of 1.46-6000 ng/mL, with a lower limit of quantitation of 1.46 ng/mL. Both intra- and interday precisions were within 11.05%, and the accuracy ranged from -11.5 to 5.51%. The extraction recovery and matrix effect were within acceptable limits. Stability tests showed that PepE remained stable throughout the analytical procedure. The validated method was then used to analyze the pharmacokinetics of PepE administered to rats orally (12.5 and 25 mg/kg) or intravenously (6.25 and 12.5 mg/kg).

  20. Liquid chromatography tandem mass spectrometry method for the quantitation of mycophenolate mofetil in human plasma: Application to a bioequivalence study and metabolite identification.

    PubMed

    Partani, Pankaj; Verma, Saurabh Manaswita; Monif, Tausif

    2015-10-01

    We established a sensitive, selective, and rapid analytical method for the quantitation and pharmacokinetic investigation of mycophenolate mofetil in human plasma. To our knowledge, this is the first method that characterizes presence of mycophenolate mofetil glucuronide in clinical samples through tandem mass spectrometry detection and resolves mycophenolate mofetil from its glucuronide metabolite. Liquid chromatography coupled to tandem mass spectrometry detection in positive ion mode was selected to provide optimal selectivity and sensitivity. Due to the ionizable characteristics of the mycophenolate mofetil, a mixed-mode cation-exchange disposable extraction cartridge was prudently chosen. The chromatographic separation was achieved on Luna(®) C18(2) (100×4.60 mm) column using mobile phase consisting of a mixture of 1±0.05 mM ammonium formate in water, titrated to pH 3.1±0.1 with formic acid, and methanol (20:80, v/v), at a flow rate of 0.7 mL/min. The detection was led at m/z ratios of 434.4→ 114.2 and 438.4→ 118.3, for mycophenolate mofetil and mycophenolate mofetil-D4, respectively. The developed method was linear between 40.2-4986.0 pg/mL. All validation parameters were within the defined limits. The validated method was then successfully applied for the evaluation of bioequivalence parameters of mycophenolate mofetil after an oral administration of 500 mg mycophenolate mofetil tablet to healthy male Indian volunteers.

  1. 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.

  2. Studies of Wettability of Medical PVC by Remote Nitrogen Plasma

    NASA Astrophysics Data System (ADS)

    Li, Ru; Chen, Jierong

    2006-05-01

    The effects of remote nitrogen plasma and nitrogen plasma on medical PVC's surface modification are studied. The surface properties are characterized by the contact angle measurement, X-ray photoelectron spectroscopy and scanning electron microscopy. Results show that the remote nitrogen plasma treatments modify the PVC surface in both morphology and composition and the treatment by the remote nitrogen plasma in PVC surface modification is more effective than that by the nitrogen plasma. Remote nitrogen plasma can modify the surface more uniformly. After the PVC surface is treated for 2 min by remote nitrogen plasma, the [w(O)+ w(N)]/w(C)] value increases from 0.13 to 0.51 and the water contact angle decreases from 89o to 18o.

  3. Development of a LC-MS/MS method for simultaneous determination of metoprolol and its metabolites, α-hydroxymetoprolol and O-desmethylmetoprolol, in rat plasma: application to the herb-drug interaction study of metoprolol and breviscapine.

    PubMed

    Rao, Zhi; Ma, Yan-rong; Qin, Hong-yan; Wang, Ya-feng; Wei, Yu-hui; Zhou, Yan; Zhang, Guo-qiang; Wang, Xing-dong; Wu, Xin-an

    2015-09-01

    A simple, specific and sensitive LC-MS/MS method was developed and validated for the simultaneous determination of metoprolol (MET), α-hydroxymetoprolol (HMT) and O-desmethylmetoprolol (DMT) in rat plasma. The plasma samples were prepared by protein precipitation, then the separation of the analytes was performed on an Agilent HC-C18 column (4.6 × 250 mm, 5 µm) at a flow rate of 1.0 mL/min, and post-column splitting (1:4) was used to give optimal interface flow rates (0.2 mL/min) for MS detection; the total run time was 8.5 min. Mass spectrometric detection was achieved using a triple-quadrupole mass spectrometer equipped with an electrospray source interface in positive ionization mode. The method was fully validated in terms of selectivity, linearity, accuracy, precision, stability, matrix effect and recovery over a concentration range of 3.42-7000 ng/mL for MET, 2.05-4200 ng/mL for HMT and 1.95-4000 ng/mL for DMT. The analytical method was successfully applied to herb-drug interaction study of MET and breviscapine after administration of breviscapine (12.5 mg/kg) and MET (40 mg/kg). The results suggested that breviscapine have negligible effect on pharmacokinetics of MET in rats; the information may be beneficial for the application of breviscapine in combination with MET in clinical therapy.

  4. 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.

  5. 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.

  6. 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

  7. Advances in experimental spectroscopy of Z-pinch plasmas and applications

    NASA Astrophysics Data System (ADS)

    Kantsyrev, V. L.; Safronova, A. S.; Safronova, U. I.; Shrestha, I.; Weller, M. E.; Osborne, G. C.; Shlyaptseva, V. V.; Wilcox, P. G.; Stafford, A.

    2012-06-01

    Recent advances in experimental work on plasma spectroscopy of Z-pinches are presented. The results of experiments on the 1.7 MA Z-pinch Zebra generator at UNR with wire arrays of various configurations and X-pinches are overviewed. A full x-ray and EUV diagnostic set for detailed spatial and temporal monitoring of such plasmas together with theoretical support from relativistic atomic structure and non-LTE kinetic codes used in the analysis are discussed. The use of a variety of wire materials in a broad range from Al to W provided an excellent opportunity to observe and study specific atomic and plasma spectroscopy features. In addition, the applications of such features to fusion and astrophysics will be considered.

  8. 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.

  9. 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.

  10. 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.

  11. Basic Studies on High Pressure Air Plasmas

    DTIC Science & Technology

    2006-08-30

    33, 2268 (2000). [3] Non- Equilibrium Air Plasmas at Atmospheric Pressure, K.H. Becker, U. Kogelschatz, K.H. Schoenbach, and R.J. Barker, eds., IOP...10). Note that LIFBASE assumes local thermodynamic equilibrium . 120 100 oExperimentalm Siuation 80 60 20- 0 -J ~ LkXi 3060 3070 3080 3090 3100...Dual laser interferometer for plasma density measurements on large tokamaks >>, Rev. Sci. Instrum. 49 p.919 (1978) [5] C.W. Gowers, C. Lamb, « A

  12. Experimental Investigation of the Plasma Bullet and Its Applications

    DTIC Science & Technology

    2012-08-01

    Atmospheric pressure, air plasma, plasma bullet, non -equilibrium 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a...be ignited. Introduction One of the attractive features of non -thermal atmospheric pressure...Plasma jets or plumes fill exactly such a niche. Background The Plasma Pencil The electron energy distribution in non -equilibrium discharges

  13. 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

  14. 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.

  15. 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.

  16. The upgraded Large Plasma Device, a machine for studying frontier basic plasma physics.

    PubMed

    Gekelman, W; Pribyl, P; Lucky, Z; Drandell, M; Leneman, D; Maggs, J; Vincena, S; Van Compernolle, B; Tripathi, S K P; Morales, G; Carter, T A; Wang, Y; DeHaas, T

    2016-02-01

    In 1991 a manuscript describing an instrument for studying magnetized plasmas was published in this journal. The Large Plasma Device (LAPD) was upgraded in 2001 and has become a national user facility for the study of basic plasma physics. The upgrade as well as diagnostics introduced since then has significantly changed the capabilities of the device. All references to the machine still quote the original RSI paper, which at this time is not appropriate. In this work, the properties of the updated LAPD are presented. The strategy of the machine construction, the available diagnostics, the parameters available for experiments, as well as illustrations of several experiments are presented here.

  17. 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.

  18. 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.

  19. Robust regression with CUDA and its application to plasma reflectometry

    NASA Astrophysics Data System (ADS)

    Ferreira, Diogo R.; Carvalho, Pedro J.; Fernandes, Horácio

    2015-11-01

    In many applications, especially those involving scientific instrumentation data with a large experimental error, it is often necessary to carry out linear regression in the presence of severe outliers which may adversely affect the results. Robust regression methods do exist, but they are much more computationally intensive, making it difficult to apply them in real-time scenarios. In this work, we resort to graphics processing unit (GPU)-based computing to carry out robust regression in a time-sensitive application. We illustrate the results and the performance gains obtained by parallelizing one of the most common robust regression methods, namely, least median of squares. Although the method has a complexity of O(n3logn), with GPU computing, it is possible to accelerate it to the point that it becomes usable within the required time frame. In our experiments, the input data come from a plasma diagnostic system installed at Joint European Torus, the largest fusion experiment in Europe, but the approach can be easily transferred to other applications.

  20. Robust regression with CUDA and its application to plasma reflectometry.

    PubMed

    Ferreira, Diogo R; Carvalho, Pedro J; Fernandes, Horácio

    2015-11-01

    In many applications, especially those involving scientific instrumentation data with a large experimental error, it is often necessary to carry out linear regression in the presence of severe outliers which may adversely affect the results. Robust regression methods do exist, but they are much more computationally intensive, making it difficult to apply them in real-time scenarios. In this work, we resort to graphics processing unit (GPU)-based computing to carry out robust regression in a time-sensitive application. We illustrate the results and the performance gains obtained by parallelizing one of the most common robust regression methods, namely, least median of squares. Although the method has a complexity of O(n(3)logn), with GPU computing, it is possible to accelerate it to the point that it becomes usable within the required time frame. In our experiments, the input data come from a plasma diagnostic system installed at Joint European Torus, the largest fusion experiment in Europe, but the approach can be easily transferred to other applications.

  1. Current status of IMS plasma wave research. [International Magnetospheric Study

    NASA Technical Reports Server (NTRS)

    Anderson, R. R.

    1982-01-01

    The present investigation is concerned with a review of the status of magnetospheric plasma wave science as a result of the International Magnetospheric Study (IMS). The presence of an international effort has supported the development and completion of the numerous magnetospheric science spacecraft launched during the IMS, including GEOS, ISEE, and EXOS B. Ground-based VLF observations are considered along with coordinated ground-based and satellite observations. During the IMS, plasma wave research using satellite data has covered a wide range of subjects. Attention is given to magnetospheric electrostatic emissions, magnetospheric electromagnetic plasma waves, continuum radiation, auroral kilometric radiation, auroral zone plasma waves, plasma waves in the magnetosheath and near the mangetopause, and plasma waves at the bow shock.

  2. 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.

  3. Low temperature plasma vapor treatment of thermo-sensitive poly(N-isopropylacrylamide) and its application

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Tang, X. L.; Chen, B. T.; Qiu, G.

    2013-03-01

    In this study, the novel methods of depositing poly(N-isopropylacrylamide) (PNIPAAm) coatings on the surface of glass slides and PS petri dish by plasma polymerization are provided. PNIPAAm can be obtained by plasma polymerization of N-isopropylacrylamide by using the self-made equipment of plasma vapor treatment. The samples were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle. SEM analysis has revealed that the poly(N-isopropylacrylamide) (PNIPAAm) coatings were formed on the surface of the smooth glass slides. Further evaluation by using XPS, it has shown the presence of PNIPAAm. The wettability can be significantly modified by changing of the temperatures at above and below of the lower critical solution temperature (LCST) from the data of the contact angle test. These results have advantage for further application on the thermo-sensitive textile materials. On the deposition of PNIPAAm onto Polybutylene Terephthalate (PBT) melt-blown nonwovens in atmospheric pressure plasma, water permeability was significantly modified at around LCST. Due to the LCST is close to the temperature of human body, it has advantage on application of PBT melt-blown nonwovens.

  4. 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.

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

    PubMed

    Liu, Jian; Shen-Tu, Jianzhong; Wu, Lihua; Dou, Jing; Xu, Qiyang; Zhou, Huili; Wu, Guolan; Hu, Xingjiang

    2012-11-01

    The purpose of this study was to design a simple and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for a rebamipide bioequivalence study in healthy Chinese male volunteers. In this method, sample pretreatment involved simple protein precipitation with venlafaxine as the internal standard. Analysis was achieved on a ZORBAX SB-C18 column with a concentration range of 6-1200 ng/mL. Rebamipide tablets from Yuanlijian (test, Hangzhou, China) and from Otsuka (reference, Hangzhou, China) were evaluated following a single 300 mg oral dose to 20 healthy volunteers. Bioequivalence was determined by calculating 90% confidence intervals (90% CI) for the ratio of Cmax, AUC(0-t) and AUC(0-infinity) values for the test and reference products, using logarithmic transformed data. The 90% confidence intervals for the ratio of Cmax (83.7-118.4%), AUC(0-t) (91.1-113.4%) and AUC(0-infinity) (90.6-113.2%) values for the test and reference products were within the interval (80.0-125.0% for AUC, and 70-143% for Cmax), proposed by State of Food and Drug Administration [SFDA, 2005. China]. It was concluded that the two rebamipide tablets were bioequivalent in their rate and extent of absorption and the method met the principle of quick and easy clinical analysis.

  6. 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.

  7. Quantification of nimesulide in human plasma by high-performance liquid chromatography with ultraviolet detector (HPLC-UV): application to pharmacokinetic studies in 28 healthy Korean subjects.

    PubMed

    Kim, Mi-Sun; Park, Yoo-Sin; Kim, Shin-Hee; Kim, Sang-Yeon; Lee, Min-Ho; Kim, Youn-Hee; Kim, Do-Wan; Yang, Seok-Chul; Kang, Ju-Seop

    2012-05-01

    Nimesulide is a selective COX-2 inhibitor that is as effective as the classical non-acidic nonsteroidal anti-inflammatory drugs in the relief of various pain and inflammatory conditions, but is better tolerated with lower incidences of adverse effects than other drugs. After oral dose of 100 mg nimesulide to western subjects, a mean maximal concentration (C(max)) of 2.86 ∼ 6.5 µg/mL was reached at 1.22 ∼ 2.75 h and mean t(1/2β) of 1.8 ∼ 4.74 h. This study developed a robust method for quantification of nimesulide for the pharmacokinetics and suitability of its dosage in Korea and compared its suitability with other racial populations. Nimesulide and internal standard were extracted from acidified samples with methyl tert-butyl ether and analyzed by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). The 28 healthy volunteers took 2 tablets of 100 mg nimesulide and blood concentrations were analyzed during the 24 h post dose. Several pharmacokinetic parameters were represented: AUC(0-infinity) = 113.0 mg-h/mL, C(max) = 12.06 mg/mL, time for maximal concentrations (T(max)) = 3.19 h and t(1/2β) = 4.51 h. These were different from those of western populations as follows: AUC was 14.5% and C(max) was 28% that of of Korean subjects and T(max) and t(1/2β) were also different. The validated HPLC-UV method was successfully applied for the pharmacokinetic studies of nimesulide in Korean subjects. Because the pharmacokinetics of nimesulide were different from western populations, its dosage regimen needs to be adjusted for Koreans.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. Controlling plasma stimulated media in cancer treatment application

    NASA Astrophysics Data System (ADS)

    Yan, Dayun; Sherman, Jonathan H.; Cheng, Xiaoqian; Ratovitski, Edward; Canady, Jerome; Keidar, Michael

    2014-12-01

    Cold atmospheric plasma (CAP) constitutes a "cocktail" of various reactive species. Accumulating evidence shows the effectiveness of CAP in killing cancer cells and decreasing the tumor size, which provides a solid basis for its potential use in cancer treatment. Currently, CAP is mainly used to directly treat cancer cells and trigger the death of cancer cells via apoptosis or necrosis. By altering the concentration of fetal bovine serum in Dulbecco's modified Eagle's medium and the temperature to store CAP stimulated media, we demonstrated controllable strategies to harness the stimulated media to kill glioblastoma cells in vitro. This study demonstrated the significant role of media in killing cancer cells via the CAP treatment.

  15. Applications and limits of platelet-rich plasma in sports related injuries.

    PubMed

    Stanco, D; Vigano', M; Croiset, S J; De Girolamo, L

    2012-01-01

    Platelet-rich plasma (PRP) is a promising alternative approach based on the efficacy of autologous growth factors to accelerate tissue healing, allowing a fast recovery after muscles, ligaments, tendon or cartilage lesions. This literature review begin focusing on the role of platelets growth factors in these tissue healing and on the available preparation methods for PRP. Moreover we consider the in vitro and in vivo study on PRP, some of the most important therapeutic applications and limitations. Although several preclinical studies show promising results, clinical studies still show controversial results. Further studies are required to define the efficacy and to specify the way of using PRP in the orthopaedic practice.

  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. Plasma Science Committee (PLSC) and study on new opportunities in plasma science and technology

    SciTech Connect

    Not Available

    1992-01-01

    The Plasma Science Committee (PLSC) of the National Research Council (NRC) is charged with monitoring the health of the field of plasma science in the United States. Accordingly, the Committee identifies and examines both broad and specific issues affecting the field. Regular meetings, teleconferences, briefings from agencies and the scientific community, the formation of study panels to prepare reports, and special symposia are among the mechanisms used by the PLSC to meet its charge. This progress report presents a review of PLSC activities from July 15, 1991 to May 31, 1992. The details of prior activities are discussed in earlier reports. This report also includes the status of activities associated with the PLSC study on opportunities in plasma science and technology. During the above period, the PLSC has continued to track and participate in, when requested, discussions on the health of the field. Much of the perspective of the PLSC has been presented in the recently-published report Research Briefing on Contemporary Problems in Plasma Science. That report has served as the basis for briefings to representatives of the federal government as well as the community-at-large. In keeping with its charge to identify and highlight specific areas for scientific and technological opportunities, the PLSC completed publication of the report Plasma Processing of Materials: Scientific and Technological Opportunities and launched a study on new opportunities in plasma science and technology.

  18. 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.

  19. An experimental study of laser supported hydrogen plasmas

    NASA Technical Reports Server (NTRS)

    Vanzandt, D. M.; Mccay, T. D.; Eskridge, R. H.

    1984-01-01

    The rudiments of a rocket thruster which receives its enthalpy from an energy source which is remotely beamed from a laser is described. An experimental study now partially complete is discussed which will eventually provide a detailed understanding of the physics for assessing the feasibility of using hydrogen plasmas for accepting and converting this energy to enthalpy. A plasma ignition scheme which uses a pulsed CO2 laser has been developed and the properties of the ignition spark documented, including breakdown intensities in hydrogen. A complete diagnostic system capable of determining plasma temperature and the plasma absorptivity for subsequent steady state absorption of a high power CO2 laser beam are developed and demonstrative use is discussed for the preliminary case study, a two atmosphere laser supported argon plasma.

  20. Study of positive and negative plasma catalytic oxidation of ethylene.

    PubMed

    Van Wesenbeeck, K; Hauchecorne, B; Lenaerts, S

    2016-10-06

    The effect of introducing a photocatalytically active coating inside a plasma unit is investigated. This technique combines the advantages of high product selectivity from catalysis and the fast start-up from plasma technology. In this study, a preselected TiO2 coating is applied on the collector electrode of a DC corona discharge unit as non-thermal plasma reactor, in order to study the oxidation of ethylene. For both positive and negative polarities an enhanced mineralization is observed while the formation of by-products drastically decreases. The plasma catalytic unit gave the best results when using negative polarity at a voltage of 15 kV. This shows the potential of plasma catalysis as indoor air purification technology.

  1. 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.

  2. 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.

  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. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. Effect of bias application to plasma density in weakly magnetized inductively coupled plasma

    SciTech Connect

    Kim, Hyuk; Lee, Woohyun; Park, Wanjae; Whang, Ki-Woong

    2013-07-15

    Independent control of the ion flux and energy can be achieved in a dual frequency inductively coupled plasma (ICP) system. Typically, the plasma density is controlled by the high-frequency antenna radio-frequency (RF) power and the ion energy is controlled by the low-frequency bias RF power. Increasing the bias power has been known to cause a decrease in the plasma density in capacitively coupled discharge systems as well as in ICP systems. However, an applied axial magnetic field was found to sustain or increase the plasma density as bias power is increased. Measurements show higher electron temperatures but lower plasma densities are obtained in ordinary ICP systems than in magnetized ICP systems under the same neutral gas pressure and RF power levels. Explanations for the difference in the behavior of plasma density with increasing bias power are given in terms of the difference in the heating mechanism in ordinary unmagnetized and magnetized ICP systems.

  10. 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).

  11. 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

  12. Tritium Plasma Experiment (TPE) - parameters and potentials for fusion plasma-wall interaction studies

    SciTech Connect

    Masashi Shimada; Robert D. Kolasinski; J. Phillip Sharpe; Rion A. Causey

    2011-08-01

    The Tritium plasma experiment (TPE) is a unique facility devoted to experiments on the behavior of deuterium/tritium in toxic (e.g. beryllium) and radioactive materials for fusion plasma-wall interaction (PWI) studies. A Langmuir probe was added to the system to characterize the plasma conditions in TPE. With this new diagnostic, we found the achievable electron temperature ranged from 5.0 to 10.0 eV, the electron density varied from 5.0 x 10{sup 16} to 2.5 x 10{sup 18} m{sup -3}, and the ion flux density varied between 5.0 x 10{sup 20} to 2.5 x 10{sup 22} m{sup -2}s{sup -1} along the centerline of the plasma. A comparison of these plasma parameters with the conditions expected for the plasma facing components (PFCs) in ITER shows that TPE is capable of achieving most (approximately 800 m{sup 2} of 850 m{sup 2} total PFCs area) of the expected ion flux density and electron density conditions.

  13. Tritium plasma experiment: Parameters and potentials for fusion plasma-wall interaction studies

    SciTech Connect

    Shimada, Masashi; Sharpe, J. Phillip; Kolasinski, Robert D.; Causey, Rion A.

    2011-08-15

    The tritium plasma experiment (TPE) is a unique facility devoted to experiments on the behavior of deuterium/tritium in toxic (e.g., beryllium) and radioactive materials for fusion plasma-wall interaction studies. A Langmuir probe was added to the system to characterize the plasma conditions in TPE. With this new diagnostic, we found the achievable electron temperature ranged from 5.0 to 10.0 eV, the electron density varied from 5.0 x 10{sup 16} to 2.5 x 10{sup 18} m{sup -3}, and the ion flux density varied between 5.0 x 10{sup 20} to 2.5 x 10{sup 22} m{sup -2} s{sup -1} along the centerline of the plasma. A comparison of