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. Verification Studies for Multi-Fluid Plasma Algorithms with Applications to Fast MHD Physics

    NASA Astrophysics Data System (ADS)

    Becker, Joe; Hakim, Ammar; Loverich, John; Stoltz, Peter

    2011-10-01

    In this paper we present a series of verification studies for finite volume algorithms in Nautilus, a numerical solver for fluid plasmas. Results include a set of typical Euler, Maxwell, MHD and Two-fluid benchmarks. In addition results and algorithms for a set of hyperbolic gauge cleaning schemes that can be applied to the MHD and Two-fluid systems using finite volume type methods will be presented. Finally we move onto applications in field reversed configuration (FRC) plasmas.

  5. 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.

  6. 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. PMID:26932094

  7. Study of DC discharge plasma polymerization kinetics, film properties and applications and initial study of silica powder surface modification by RF plasma polymerization

    NASA Astrophysics Data System (ADS)

    Guo, Sheyu

    1998-09-01

    In this work, two kinds of plasma polymerization for surface modification are discussed. In part-I, DC plasma polymerization is investigated for film properties, film growth mechanism and film application. The monomers heaxamethyldisiloxane (HMDSO) and pyrrole were selected to study the deposition rates change with discharge parameters such as pressure, flow rate, power, discharge current density. Structures and properties of film deposited at extreme conditions (high power/low pressure or low power/high pressure) were studied with FT-IR, SEM, TOF-SIMS, AIM, surface energy measurement and tribology test. This work also investigated DC plasma polymerization kinetics by combining plasma parameters with film deposited rate at different conditions. Both single and double Langmuir probes were used to measure the plasma parameters in pulsed power and continuous discharges. Plasma density and electron temperature are reported. A DC plasma polymerization kinetic model is Proposed based on the experimental data and a best-fit mathematical method. DC plasma polymerization application was the other object of this study. Cold-rolled steel and copper were coated with pyrrole and HMDSO, respectively. Corrosion rate were obtained from electrochemical polarization methods, and tests in humidity chamber directly. Various monomers were used to change the substrate surface energy. Hydrophilic and hydrophobic surface were achieved respectively by different monomers. A water-soluble film was obtained with acrylic acid in mild plasma conditions. In part-II, a initial study of powder surface modification has been done. The aim of this work was to investigate the possibility of changing powder surface properties with plasma-polymerized coatings. RF inductive plasma was used as a source to excite plasma polymerization for powder treatment. Plasma-polymerized pyrrole films were deposited on silica surface. Several techniques such as SEM, EDX, TOF-SIMS, FT-IF, DSC&TGA, and surface energy

  8. Application of electroimmunoassay to the study of plasma protein synthesis in cultured hepatocytes.

    PubMed

    Grieninger, G; Pindyck, J; Hertzberg, K M; Mosesson, M W

    1979-01-01

    Electroimmunoassay has been applied to the study of plasma protein synthesis and secretion in liver cell cultures. The assay is performed on unconcentrated samples of culture medium containing the secreted plasma proteins and yields results within 2 hours. The characteristics of plasma protein production by the cultured hepatocytes coupled with the sensitivity of this assay permit the study of plasma protein in synthesis and its regulation by hormones and other agents without the routine use of radioisotopes. PMID:518014

  9. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

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

    NASA Astrophysics Data System (ADS)

    Watanabe, Takayuki

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

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

    PubMed

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

    2015-01-01

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

  14. 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.

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

    NASA Technical Reports Server (NTRS)

    Dzhakov, B. Y.

    1973-01-01

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

  16. 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.

  17. Application of x-ray-laser interferometry to study high-density laser-produced plasmas

    SciTech Connect

    Wan, A.S.; Da Silva, L.B.; Barbee, T.W. Jr.; Cauble, R.; Celliers, P.; Libby, S.B.; London, R.A.; Moreno, J.C.; Trebes, J.E.; Weber, F.

    1996-02-01

    Collisionally pumped soft-x-ray lasers now operate over a wavelength range extending from 4 to 40 nm. With the recent advances in the development of multilayer mirrors and beam splitters in the soft-x-ray regime, we can utilize the unique properties of x-ray lasers to study large, rapidly evolving laser-driven plasmas with high electron densities. Using a neonlike yttrium x-ray laser, which operates at a wavelength of 15.5 nm, we have performed a series of radiography, moir{acute e} deflectometry, and interferometry experiments to characterize plasmas relevant to inertial confinement fusion. We describe experiments using a soft-x-ray laser interferometer, operated in the Mach{endash}Zehnder configuration, to study CH plasmas. The two-dimensional density profiles obtained from the interferograms allow us to validate and benchmark our numerical models used to study the physics of laser{endash}plasma interactions. {copyright} {ital 1996 Optical Society of America.}

  18. 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.

  19. Desulfurization study of hydrocarbon molecules by plasma process for gasoil applications

    SciTech Connect

    Mohammedi, M.N.; Leuenberger, J.L.; Amouroux, J.

    1996-12-31

    During these last years, many investigations have been made on sulphur elimination processes from hydrocarbon feedstocks because of environmental regulations which are more and more strict. This is a study on a plasma process dedicated to heavy hydrocarbon hydrotreatment and hazardous substances removing such as sulphur compounds. It is a co-processing of a fluidized spouted bed and an inductively coupled plasma working at atmospheric pressure. A high flow of hydrogen radicals is generated and a rapid quench of the plasma leads to an increase of hydrogen radical life-time and promotes chemical reactions of desulfurization at low temperature (700-900 K). The primary objective of this work is to understand the cleavage of C-S bond under these plasma conditions. To this end, thermodynamic calculations are done and preliminary experiments are carried out with different mixtures where n-hexadecane is chosen as the model molecule in hydrocarbon hydrocracking, and sulphur compounds are added in small amounts (0-1 % S wt). Compounds such as dimethyl sulphide, 2-butanethiol, benzothiophene and thiophene are currently studied. The influence of CH{sub 3}{degrees}, H{degrees}, HS{degrees} and PhS{degrees} (C{sub 6}H{sub 5}S{degrees}) is also considered.

  20. Desulfurization study of hydrocarbon molecules by plasma process for gasoil applications

    SciTech Connect

    1996-10-01

    During these last years, many investigations have been made on sulfur elimination processes from hydrocarbons feedstocks because of environmental regulations which are more and more strict. This is a study on a plasma process dedicated to heavy hydrocarbon hydrotreatment and hazardous substances removing such as sulphur compounds. It is a co-processing of a fluidized spouted bed and an inductively coupled plasma working at atmospheric pressure. A high flow of hydrogen radicals is generated and a rapid quench of the plasma leads to an increase of hydrogen radical life-time and promotes chemical reactions of desulfurization at low temperature (700-900 K). The primary objective of this work is to understand the cleavage of C-S bond under these plasma conditions. To this end, thermodynamical calculations are done and preliminary experiments are carried out with different mixtures where n-hexadecane is chosen as the model molecule in hydrocarbon hydrocracking, and sulfur compounds are added in small amounts (0-1% s mass). Compounds such as dimethyl sulfide, 2-butanethiol, benzothiophen and thiophen are currently studied. The influence of CH3{degrees}, H{degrees}, HS{degrees} and {Phi} is also considered.

  1. 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. PMID:26760223

  2. Monte Carlo application based on GEANT4 toolkit to simulate a laser-plasma electron beam line for radiobiological studies

    NASA Astrophysics Data System (ADS)

    Lamia, D.; Russo, G.; Casarino, C.; Gagliano, L.; Candiano, G. C.; Labate, L.; Baffigi, F.; Fulgentini, L.; Giulietti, A.; Koester, P.; Palla, D.; Gizzi, L. A.; Gilardi, M. C.

    2015-06-01

    We report on the development of a Monte Carlo application, based on the GEANT4 toolkit, for the characterization and optimization of electron beams for clinical applications produced by a laser-driven plasma source. The GEANT4 application is conceived so as to represent in the most general way the physical and geometrical features of a typical laser-driven accelerator. It is designed to provide standard dosimetric figures such as percentage dose depth curves, two-dimensional dose distributions and 3D dose profiles at different positions both inside and outside the interaction chamber. The application was validated by comparing its predictions to experimental measurements carried out on a real laser-driven accelerator. The work is aimed at optimizing the source, by using this novel application, for radiobiological studies and, in perspective, for medical applications.

  3. 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.

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

    PubMed Central

    Amini, Hossein; Ahmadiani, Abolhassan

    2010-01-01

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

  5. 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.

  6. RP-HPLC analysis of flucloxacillin in human plasma: validation and application to a bioequivalence study.

    PubMed

    Zhou, Q; Ruan, Z; Yuan, H; Jiang, B; Xu, D

    2007-02-01

    A RP-HPLC method with rapid sample processing was developed for quantitation of flucloxacillin in human plasma using dicloxacillin as the internal standard. The plasma sample (100 microL) was acidified with glacial acetic acid, and deproteinized by precipitation with acetonitrile. The supernatant was directly injected into the HPLC system. Separation was achieved on an Alltima C18 column (250 mmx4.6 mm I.D., 5 microm), with a mixture of 10 mmol x L(-1) KH2PO4-acetonitrile (64.5:35.5, v/v) as mobile phase. The assay was successfully applied to a randomized, two-period cross-over bioequivalence study in 20 healthy Chinese volunteers following a single oral dose of 250 mg flucloxacillin capsules. A non-compartmental method was used for pharmacokinetic analysis. Compared with data in the literature, flucloxacillin was eliminated more slowly in Chinese than in Caucasians. Cmax, AUC(0-t) and AUC(0-infinity) were tested for bioequivalence after log-transformation of data. No significant difference was found. Tmax was analyzed by Wilcoxon's test and no significant difference was obtained (P > 0.05). Based on these statistical inferences, the two formulations were judged to be bioequivalent and, thus, can be prescribed interchangeably. PMID:17341027

  7. Proteomics of boar seminal plasma - current studies and possibility of their application in biotechnology of animal reproduction.

    PubMed

    Strzeżek, Jerzy; Wysocki, Paweł; Kordan, Władysław; Kuklińska, Magdalena; Mogielnicka, Marzena; Soliwoda, Daniel; Fraser, Leyland

    2005-11-01

    Proteomics is critical to identify the properties and functions of proteins involved in the mechanism regulating the male reproductive tract function. This approach is important in male fertility assessment and clinical diagnosis of the physiological state of individual reproductive organs. Proteomics also provides a tool to understand the interactions of seminal plasma proteins with spermatozoa, which could provide a useful model for studying ligand-cell interaction occurring at the sperm cell surface. This review covers a selection of advances in the realm of functional proteomics of boar seminal plasma proteins and is focused on some fundamental proteomic technologies. Also, this review explores key themes in proteomics and their application in animal reproductive techniques. PMID:16372045

  8. 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

  9. 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. PMID:12763542

  10. 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.

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

    PubMed

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

    2015-11-01

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

  12. Application of Gaseous Laser Targets and Optical Diagnostics to Study High Mach Number Unstable Plasma Flows

    SciTech Connect

    Edwards, J; MacKinnon, A; Robey, H

    2001-04-01

    The information that can be obtained from current laser driven high Mach number (compressible) hydrodynamics experiments using solid targets and foams is limited by the need to use X-ray diagnostics. These do well at providing the shape of gross 2D structures which we model well, but are a long way from being able to reveal detailed information at the smaller spatial scales, or in 3D turbulent flows, where most of the modeling uncertainties exist. Remedying this is, and will continue to be, an ongoing research effort. An alternative approach that is not being considered is to use gaseous targets coupled with optical diagnostics. The lower density of gases compared to solids or foams means we can use much larger targets for a given laser energy. This should significantly improve spatial resolution, and the dynamic range of scales that are resolvable. In addition, it may be possible to adapt powerful techniques, such as LIF, used by the low Mach number (incompressible) fluid/gas community so that they work in the high Mach number plasma regime. This would provide much more detailed information on turbulent flows than could be achieved with current X-ray diagnostics. We propose a small research effort to use established techniques such as optical interferometry (absolute electron density), and Schlieren photography (electron density gradient), to study compressible hydrodynamic instabilities. We also propose to explore whether techniques such as LIF may be adapted to the plasma regime, thus providing detailed information, particularly about turbulent flows, that is not currently obtainable in plasmas using X-ray diagnostics. The setting will be radiating blast waves, which avoids costly target fabrication, while promising a high physics payoff to the astrophysics community just from using the established diagnostics alone. We propose to conduct the work in collaboration with Dr Todd Ditmire at the University of Texas at Austin, principally on the Janus laser, and

  13. 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.

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

    PubMed

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

    2016-02-01

    A simple, sensitive and specific liquid chromatography tandem mass spectrometry (LC-ESI-MS/MS) method was developed for the quantification of desvenlafaxine in human plasma using desvenlafaxine d6 as an internal standard (IS). Chromatographic separation was performed using a Thermo-BDS hypersil C8 column (50 × 4.6 mm, 3 µm) with an isocratic mobile phase composed of 5 mM ammonium acetate buffer: methanol (20:80, v/v), at a flow rate of 0.80 mL/min. Desvenlafaxine and desvenlafaxine d6 were detected with proton adducts at m/z 264.2/58.1 and 270.2/ 64.1 in multiple reaction monitoring positive mode, respectively. Liquid-liquid extraction was used to extract the drug and the IS. The method was linear over the concentration range 1.001-400.352 ng/mL with a correlation coefficient of ≥0.9994. This method demonstrated intra and inter-day precision within 0.7-5.5 and 1.9-6.8%, and accuracy within 95.3-107.4 and 93.4-99.5%. Desvenlafaxine was found to be stable throughout the freeze-thaw cycles, bench-top and long-term matrix stability studies. The developed and validated method can be successfully applied for the bioequivalence/pharmacokinetic studies of desvenlafaxine in pharmaceutical dosage forms. PMID:26095112

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

    NASA Astrophysics Data System (ADS)

    Al Agry, Ahmad Farouk

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

  16. Study of the adhesion of thin plasma fluorocarbon coatings resisting plastic deformation for stent applications

    NASA Astrophysics Data System (ADS)

    Lewis, F.; Horny, P.; Hale, P.; Turgeon, S.; Tatoulian, M.; Mantovani, D.

    2008-02-01

    Metallic intravascular stents are medical devices (316L stainless steel) used to support the narrowed lumen of atherosclerotic stenosed arteries. Despite the success of bare metal stents, restenosis remains the main complication after 3-6 months of implantation. To reduce the restenosis rate of bare metal stents, stent coating is an interesting alternative. Firstly, it allows the modification of the surface properties, which is in contact with the biological environment. Secondly, the coating could eventually act as a carrier for drug immobilization and release. Moreover, the in vivo stent implantation requires in situ stent expansion. This mandatory step generates local plastic deformation of up to 25% and may cause coating failures such as cracking and delamination. Fluorocarbon films were selected in this study as a potential stent coating, mainly due to their chemical inertness, high hydrophobicity, protein retention capabilities and thromboresistance properties. The aim of this study was to investigate the adhesion properties of fluorocarbon films of three different thicknesses deposited by plasma polymerization in C2F6/H2 on 316L stainless steel substrates. A previously developed small punch test was used to deform the coated samples. According to atomic force microscopy, field emission scanning electron microscopy and x-ray photoelectron spectroscopy characterizations, among the coatings with different thicknesses studied, only those with a thickness of 36 nm exhibited the required cohesion and interfacial adhesion to resist the stent expansion without cracking or delaminating. Otherwise, cracks were detected in the coatings having thicknesses equal or superior to 100 nm, indicating a lack of cohesion.

  17. 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.

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

    PubMed

    Tong, Qing; Hou, Xiaolong; Fang, Jianguo; Wang, Wenqing; Xiong, Wei; Liu, Xu; Xie, Xuejia; Shi, Chunyang

    2015-10-10

    Ampelopsis grossedentata (Hand.-Mazz.) W.T. Wang has long been used as a traditional Chinese medicinal herb among the indigenous people in the Yangtze River region of China. Dihydromyricetin (DMY) is the most abundant (approximately 30%) and bioactive constituent in A. grossedentata (Hand.-Mazz.) W.T. Wang, and recent studies have demonstrated its various pharmacological activities. In the present study, a first specific, sensitive, rapid and reliable LC-MS/MS method for the determination of DMY in rat plasma was developed and validated. The plasma samples were prepared with protein precipitation method, and chromatographic separation was performed on a Welch Ultimate XB-C18 column (50 × 2.1 mm, 5 μm) using a gradient elution with water and acetonitrile. The mass spectrometry (MS) analysis was conducted in negative ionization mode with multiple reaction monitoring (MRM) transitions at m/z 319.1→192.8 for DMY and m/z 609.0→301.2 for rutin (IS). The plasma concentration profiles and pharmacokinetic parameters were analyzed after oral administration of dextroisomer and racemate DMY at the dose of 100 mg/kg in rats. The method validation was conducted over the calibration range of 10.0-5000 ng/ml with the intra- and inter-day precision and accuracy within 12.0% (RSD) and 5.6% (RE). The recoveries, matrix effect and stability under different conditions were all proved acceptable. The values of Tmax, AUC(0-∞) and Vd were significantly different between the groups of dextroisomer and racemate DMY (P<0.05), and pharmacokinetic results revealed their poor absorptions into blood, probably high tissue distributions and slow elimination processes. The present study will provide helpful information for the further studies and future clinical applications of DMY. PMID:26133104

  19. Determination of pinostilbene in rat plasma by LC-MS/MS: Application to a pharmacokinetic study.

    PubMed

    Chen, Wan; Yeo, Samuel Chao Ming; Chuang, Xue Fen; Lin, Hai-Shu

    2016-02-20

    Pinostilbene (3-methoxyresveratrol or trans-3,4'-dihydroxy-5-methoxystilbene) is a naturally occurring monomethylether analogue of resveratrol (trans-3,5,4'-trihydroxystilbene) that exhibits various pharmacological activities. To further examine its medicinal potential, a sensitive LC-MS/MS method was developed and validated for the determination of pinostilbene in rat plasma. Heavy Isotope labelled resveratrol was used as an internal standard. The ESI was operated in its negative ion mode while pinostilbene and resveratrol were measured by multiple reaction monitoring (MRM) using precursor-to-product ion transitions of m/z 241→181 and m/z 233→191, respectively. This LC-MS/MS method had excellent selectivity, sensitivity (LLOQ=1ng/ml), accuracy (both intra- and interday analytical recovery within 100±15%) and precision (both intra- and interday RSD < 15%). The matrix effect was insignificant. The pharmacokinetics of pinostilbene was subsequently profiled in Sprague-Dawley rats. Upon intravenous administration (5 or 10mg/kg), pinostilbene displayed rapid clearance (Cl=129±42 or 107±31ml/min/kg) and extremely short mean transit time (MTT=6.24±0.41 or 8.52±1.38min). After oral dosing (50mg/kg), the bioavailability of pinostilbene was limited but highly erratic (F=1.87±2.67%). Pharmacokinetic comparison among pinostilbene, resveratrol and some resveratrol analogues suggested that stilbenes with meta-hydroxyl group(s) may be associated with metabolic instability and subsequently suffer from rapid clearance and low oral bioavailability. The information obtained from this study will facilitate further exploration on pinostilbene as well as other resveratrol analogues. PMID:26771130

  20. 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.

  1. Plasma propulsion for space applications

    NASA Astrophysics Data System (ADS)

    Fruchtman, Amnon

    2000-04-01

    The various mechanisms for plasma acceleration employed in electric propulsion of space vehicles will be described. Special attention will be given to the Hall thruster. Electric propulsion utilizes electric and magnetic fields to accelerate a propellant to a much higher velocity than chemical propulsion does, and, as a result, the required propellant mass is reduced. Because of limitations on electric power density, electric thrusters will be low thrust engines compared with chemical rockets. The large jet velocity and small thrust of electric thrusters make them most suitable for space applications such as station keeping of GEO communication satellites, low orbit drag compensation, orbit raising and interplanetary missions. The acceleration in the thruster is either thermal, electrostatic or electromagnetic. The arcjet is an electrothermal device in which the propellant is heated by an electric arc and accelerated while passing through a supersonic nozzle to a relatively low velocity. In the Pulsed Plasma Thruster a solid propellant is accelerated by a magnetic field pressure in a way that is similar in principle to pulsed acceleration of plasmas in other, very different devices, such as the railgun or the plasma opening switch. Magnetoplasmadynamic thrusters also employ magnetic field pressure for the acceleration but with a reasonable efficiency at high power only. In an ion thruster ions are extracted from a plasma through a double grid structure. Ion thrusters provide a high jet velocity but the thrust density is low due to space-charge limitations. The Hall thruster, which in recent years has enjoyed impressive progress, employs a quasi-neutral plasma, and therefore is not subject to a space-charge limit on the current. An applied radial magnetic field impedes the mobility of the electrons so that the applied potential drops across a large region inside the plasma. Methods for separately controlling the profiles of the electric and the magnetic fields will

  2. Application of tomographic particle image velocimetry to studies of transport in complex (dusty) plasma

    SciTech Connect

    Williams, Jeremiah D.

    2011-05-15

    Over the past twelve years, two-dimensional and stereoscopic particle image velocimetry (PIV) techniques have been used to obtain detailed measurements of the thermal and transport properties of the microparticle component of dusty plasma systems. This letter reports on an extension of these techniques to obtain a volumetric, three-dimensional velocity vector measurement using tomographic PIV. Initial measurements using the tomographic PIV diagnostic are presented.

  3. 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. PMID:26094207

  4. The study of FTO surface texturing fabrication using Argon plasma etching technique for DSSC applications

    NASA Astrophysics Data System (ADS)

    Jayanti, Lindha; Kusumandari; Sujitno, Tjipto; Suryana, Risa

    2016-02-01

    This paper is aimed to investigate the fabrication of the fluorine-doped tin oxide (FTO) texturing by using Argon (Ar) plasma etching. The pressure and temperature of Ar gas during plasma etching were 1.6 mbar and 240-285oC, respectively. The plasma etching time was varied from 3 and 10 min. We also prepared without etching samples as reference. UV-Vis spectrophotometer showed that the transmittances of etching samples are higher than the without etching samples. The root mean square roughness (Rq) of etching samples are lower than the without etching samples. It is considered that the Ar ions bombardment can modify the FTO surfaces. However, the etching time does not significantly affect the FTO surfaces for 3 min and 10 min. The Rq of the without etching sample, the etching sample for 3 min, and the etching sample for 10 min are 11.697 nm, 9.859 nm, and 9.777 nm, respectively. These results are good agreement with the four point probe measurement that indicated that the sheet resistance (RS) for each the without sample, the etching sample for 3 min, and the etching sample for 10 min are 16.817 Ωsq, 16.067 Ω/sq, and 15.990 Ω/sq. In addition, the optical transmittance of the etching sample for 3 min and the etching sample for 10 min at wavelengths of 350 - 850 nm are almost similar. This is evidence that the etching time below 10 min cannot significantly change the morphology, optical and electrical properties.

  5. Laboratory and Space Plasma Studies

    NASA Astrophysics Data System (ADS)

    Hyman, Ellis

    1996-08-01

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

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

    PubMed

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

    2014-11-01

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

  7. Improved RP-HPLC method to determine biapenem in human plasma/urine and its application to a pharmacokinetic study.

    PubMed

    Zhao, Libo; Liu, Yi; Kou, Zhibin; Bayasi, Aidijie; Cai, Huan; Zhang, Chunyan; Wang, Qian; Li, Yuzhen; Fang, Yi

    2011-01-01

    Existing methods to determine biapenem (CAS 120410-24-4), a carbapenem, either lacked sensitivity/reproducibility or had no internal standard as a control. Here an improved reversed-phase high-performance liquid chromatographic (RP-HPLC) method was established in human plasma and urine. After adding p-aminobenzoic acid as the internal standard to plasma or urine, plasma samples were ultra-filtrated and urine samples were diluted directly. Chromatographic separations were carried out on a 4.6 mm x 150 mm column with acetonitrile-0.1 mol/l sodium acetate (2:98, v:v; pH 4.38 or 4.00) as mobile phase and UV detection at 300 nm. The extraction recovery was 91.51% for biapenem at the concentration level of 5 microg /ml in human plasma. The linear quantification range of the method was 0.1 to approximately 50 microg /ml for plasma and urine, with linear correlation coefficients greater than 0.998. The intra-day and inter-day relative standard deviations (R.S.D.) for biapenem at low, middle and high levels in human samples were less than 12.51% for plasma and less than 7.05% for urine. The RP-HPLC method was successfully applied to pharmacokinetic studies, in which healthy subjects received multiple doses of biapenem (300 mg, i.v., b.i.d., for 5 continuous days). The pharmacokinetic results are presented. PMID:21528646

  8. 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.

  9. Fundamental processes of fuel removal by cyclotron frequency range plasmas and integral scenario for fusion application studied with carbon co-deposits

    NASA Astrophysics Data System (ADS)

    Möller, S.; Wauters, T.; Kreter, A.; Petersson, P.; Carrasco, A. G.

    2015-08-01

    Plasma impact removal using radio frequency heated plasmas is a candidate method to control the co-deposit related tritium inventory in fusion devices. Plasma parameters evolve according to the balance of input power to losses (transport, radiation, collisions). Material is sputtered by the ion fluxes with impact energies defined by the plasma sheath. H2, D2 and 18O2 plasmas are produced in the carbon limiter tokamak TEXTOR. Pre-characterised a-C:D layers are exposed to study local removal rates. The D2 plasma exhibits the highest surface release rate of 5.7 ± 0.9 ∗ 1019 D/m2s. Compared to this the rate of the O2 plasma is 3-fold smaller due to its 11-fold lower ion flux density. Re-deposition of removed carbon is observed, indicating that pumping and ionisation are limiting the removal in TEXTOR. Presented models can explain the observations and allow tailoring removal discharges. An integral application scenario using ICWC and thermo-chemical removal is presented, allowing to remove 700 g T from a-C:DT co-deposits in 20 h with fusion compatible wall conditions using technical specifications similar to ITER.

  10. 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. PMID:26821881

  11. 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.

  12. Determination of phillyrin in rat plasma by high-performance liquid chromatography and its application to pharmacokinetic studies.

    PubMed

    Li, Yun-Xia; Jiang, Xue-Hua; Huang, Liang; Lu, Jing; Zhou, Jing

    2006-05-01

    A simple high-performance liquid chromatographic method was developed to study the pharmacokinetics of phillyrin in rat after intravenous administration. Plasma was extracted with ethyl acetate after addition of the internal standard, arctiin. Separation was achieved on a reversed-phase C18 column with UV detection at 228 nm. The calibration curves were linear ranging from 0.052 to 26.670 microg/ml. The intra- and inter-day precisions were no more than 9.83% and 12.31%, respectively. The average recovery of phillyrin was 95.44% from plasma. And the limit of quantification (LOQ) was estimated as 0.026 microg/ml with an intra-day relative standard deviation (R.S.D.)plasma and the assay has been applied successfully to the in vivo kinetic study of phillyrin in rats. PMID:16413739

  13. Simultaneous HPLC analysis of triamcinolone acetonide and budesonide in microdialysate and rat plasma: application to a pharmacokinetic study.

    PubMed

    Vieira, Manuela de L T; Singh, Rajandra P; Derendorf, Hartmut

    2010-11-01

    A specific and reliable HPLC-PDA method for the quantitative determination of triamcinolone acetonide, budesonide and fluticasone propionate (as internal standards) in small volumes of microdialysate and rat plasma was developed. An efficient solid-phase extraction (SPE) procedure for plasma samples yielded extremely clean extracts with overall recovery of 104.3% and 95.7% for triamcinolone acetonide (TA) and fluticasone propionate, respectively. Plasma extracts obtained after SPE and microdialysis samples were directly injected on a C18 column to separation. The method has been validated with good linearity, sensitivity, specificity and high accuracy (RE -5.28% to 9.14%) and precision (CV 0.50% to 6.62%) on both matrices. In stability studies, TA and budesonide were stable during storage and assay procedures. The method was applied to a pharmacokinetic study in rodents using microdialysis to determine protein unbound TA concentrations in blood and muscle. PMID:20884303

  14. HPLC-FLD methods to quantify chloroaluminum phthalocyanine in nanoparticles, plasma and tissue: application in pharmacokinetic and biodistribution studies.

    PubMed

    Oliveira, Líliam Teixeira; Garcia, Giani Martins; Kano, Eunice Kazue; Tedesco, Antônio Cláudio; Mosqueira, Vanessa Carla Furtado

    2011-08-25

    Analytical and bioanalytical methods of high-performance liquid chromatography with fluorescence detection (HPLC-FLD) were developed and validated for the determination of chloroaluminum phthalocyanine in different formulations of polymeric nanocapsules, plasma and livers of mice. Plasma and homogenized liver samples were extracted with ethyl acetate, and zinc phthalocyanine was used as internal standard. The results indicated that the methods were linear and selective for all matrices studied. Analysis of accuracy and precision showed adequate values, with variations lower than 10% in biological samples and lower than 2% in analytical samples. The recoveries were as high as 96% and 99% in the plasma and livers, respectively. The quantification limit of the analytical method was 1.12 ng/ml, and the limits of quantification of the bioanalytical method were 15 ng/ml and 75 ng/g for plasma and liver samples, respectively. The bioanalytical method developed was sensitive in the ranges of 15-100 ng/ml in plasma and 75-500 ng/g in liver samples and was applied to studies of biodistribution and pharmacokinetics of AlClPc. PMID:21596512

  15. Studies on counterstreaming plasma expansion

    NASA Technical Reports Server (NTRS)

    Singh, N.; Thiemann, H.; Schunk, R. W.

    1986-01-01

    Recent studies on counterstreaming plasma expansions are summarized. The basic phenomenon of plasma expansion is reviewed, and results from one-dimensional simulations of counterstreaming plasma expansion are discussed. Results from simulations based on an electrostatic particle-in-cell code, in which the dynamics of both the electrons and ions are exactly followed, are discussed. The formation of electrostatic shocks is addressed. Finally, results are presented on the ionospheric plasma expansion along the geomagnetic flux tubes by solving the hydrodynamic equations.

  16. 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).

  17. 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.

  18. Determination of afloqualone in human plasma using liquid chromatography/tandem mass spectrometry: Application to pharmacokinetic studies in humans.

    PubMed

    Yun, Hwi-Yeol; Lee, Seo-Pan; Jeong, Hae Hum; Yoon, Young-Ran; Sohn, Soo Jung; Kim, Sang Kyum; Kang, Wonku; Kwon, Kwang-Il

    2007-10-15

    Two methods for determining the central-acting muscle relaxant afloqualone in human plasma were developed and compared using API2000 and API4000 liquid chromatography tandem mass spectrometry (LC/MS/MS) systems. In the API2000 LC/MS/MS system, afloqualone and the internal standard methaqualone were extracted from plasma using a methyl-tertiary ether. After drying the organic layer, the residue was reconstituted in a mobile phase (0.1% formic acid-acetonitrile:0.1% formic acid buffer, 80:20 v/v) and injected onto a reversed-phase C(18) column. The isocratic mobile phase was eluted at 0.2ml/min. The ion transitions monitored in multiple reaction-monitoring mode were m/z 284-->146 and 251-->117 for afloqualone and methaqualone, respectively. Sample preparation for the API4000LC/MS/MS system involved simple protein precipitation with an organic mixture (methanol:10% ZnSO(4)=8:2). The ion transitions monitored in multiple reaction-monitoring mode were m/z 284-->146 and 251-->131 for afloqualone and methaqualone, respectively. In both assays, the coefficient of variation of the precision was less than 11.8%, the accuracy exceeded 91.5%, the limit of quantification was 0.5ng/ml, and the limit of detection was 0.1ng/ml for afloqualone. Two methods were used to measure the plasma afloqualone concentration in healthy subjects after a single oral 20-mg dose of afloqualone. During subsequent application of the methods, we observed that high-concentration plasma samples (>7ng/ml) prepared using the protein precipitation method resulted in about 20% higher afloqualone concentrations than with plasma samples prepared using the liquid-liquid extraction method. We believe that this phenomenon was related to the cleanness of the sample and its chemical nature. PMID:19073082

  19. 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.

  20. 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.

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

    PubMed

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

    2015-10-15

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

  2. Determination of Apremilast in Rat Plasma by UPLC-MS-MS and Its Application to a Pharmacokinetic Study.

    PubMed

    Chen, Lian-Guo; Wang, Zhe; Wang, Shujun; Li, Tao; Pan, Yongyang; Lai, Xixi

    2016-09-01

    A rapid, sensitive and selective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) was developed and validated for the determination and pharmacokinetic investigation of apremilast in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2 mL of acetonitrile to a 0.1 mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 3.0 min, and the elution of apremilast was at 1.27 min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring mode using the respective transitions m/z 461.3 → 257.1 for apremilast and m/z 237.2 → 194.2 for carbamazepine (internal standard). The calibration curve was linear over the range of 0.1-100 ng/mL with a lower limit of quantitation of 0.1 ng/mL. The mean recovery of apremilast in plasma was in the range of 83.2-87.5%. Both intraday and interday precision were <9.6%. This method was successfully applied in the pharmacokinetic study after oral administration of 6.0 mg/kg apremilast in rats. PMID:27165568

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

    PubMed

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

    2016-06-15

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

  4. Feasibility study to evaluate plasma quench process for natural gas conversion applications. [Quarterly report], July 1, 1993--September 30, 1993

    SciTech Connect

    Thomas, C.P.; Kong, P.C.; Detering, B.A.

    1993-12-31

    The objective of this work was to conduct a feasibility study on a new process, called the plasma quench process, for the conversion of methane to acetylene. FY-1993 efforts were focused on determining the economic viability of this process using bench scale experimental data which was previously generated. This report presents the economic analysis and conclusions of the analysis. Future research directions are briefly described.

  5. 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

  6. 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.

  7. Study of plasma modified-PTFE for biological applications: relationship between protein resistant properties, plasma treatment, surface composition and surface roughness

    PubMed Central

    Vandencasteele, Nicolas; Nisol, Bernard; Viville, Pascal; Lazzaroni, Roberto; Castner, David G.; Reniers, François

    2013-01-01

    PTFE samples were treated by low-pressure, O2 RF plasmas. The adsorption of BSA was used as a probe for the protein resistant properties. The exposure of PTFE to an O2 plasma leads to an increase in the chamber pressure. OES reveals the presence of CO, CO2 and F in the gas phase, indicating a strong etching of the PTFE surface by the O2 plasma. Furthermore, the high resolution C1s spectrum shows the appearance of CF3, CF and C-CF components in addition to the CF2 component, which is consistent with etching of the PTFE surface. WCA as high as 160° were observed, indicating a superhydrophobic behaviour. AFM Images of surfaces treated at high plasma power showed a increase in roughness. Lower amounts of BSA adsorption were detected on high power, O2 plasma-modified PTFE samples compared to low power, oxygen plasma-modified ones. PMID:24795545

  8. Modeling atmospheric pressure plasmas for biomedical applications

    NASA Astrophysics Data System (ADS)

    Graves, David

    2007-10-01

    The use of cold, atmospheric pressure plasmas for biomedical treatments is an exciting new application in gaseous electronics. Investigations to date include various tissue treatments and surgery, bacterial destruction, and the promotion of wound healing, among others. In this talk, I will present results from modeling the `plasma needle,' an atmospheric pressure plasma configuration that has been explored by several groups around the world. The biomedical efficacy of the plasma needle has been demonstrated but the mechanisms of cell and tissue modification or bacterial destruction are only just being established. One motivation for developing models is to help interpret experiments and evaluate postulated mechanisms. The model reveals important elements of the plasma needle sustaining mechanisms and operating modes. However, the extraordinary complexity of plasma-tissue interactions represents a long-term challenge for this burgeoning field.

  9. Determination of pinocembrin in human plasma by solid-phase extraction and LC/MS/MS: application to pharmacokinetic studies.

    PubMed

    Yan, Bei; Cao, Guoying; Sun, Taohua; Zhao, Xi; Hu, Xin; Yan, Jiling; Peng, Yueying; Shi, Aixin; Li, Yang; Xue, Wei; Li, Min; Li, Kexin; Liu, Yingfa

    2014-12-01

    A sensitive, fast and specific method for the quantitation of pinocembrin in human plasma based on high-performance liquid chromatography-tandem mass spectrometry (LC/MS/MS) was developed and validated. Clonazepam was used as the internal standard (IS). After solid-phase extraction of 500 μL plasma, pinocembrin and the IS were separated on a Luna C8 column using the mobile phase composed of acetonitrile-0.3 mm ammonium acetate solution (65:35, v/v) at a flow rate of 0.25 mL/min in isocratic mode. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring via an electrospray ionization source in negative mode by AB SCIEX Qtrap 5500. The assay was linear from 1 to 400 ng/mL, with within- and between-run accuracy (relative error) from -1.82 to 0.54%, and within- and between-run precision (CV) below 5.25%. The recovery was above 88% for the analyte at 1, 50 and 300 ng/mL. This analytical method was successful for the determination of pinocembrin in human plasma and applied to a pharmacokinetic study of pinocembrin injection in healthy volunteers after intravenous drip administration. PMID:24733513

  10. Determination and validation of hupehenine in rat plasma by UPLC-MS/MS and its application to pharmacokinetic study.

    PubMed

    Wen, Congcong; Wang, Shuanghu; Huang, Xueli; Liu, Zezheng; Lin, Yingying; Yang, Suping; Ma, Jianshe; Zhou, Yunfang; Wang, Xianqin

    2015-12-01

    In this work, a sensitive and selective ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determination of hupehenine in rat plasma was developed and validated. After addition of imperialine as an internal standard (IS), protein precipitation by acetonitrile-methanol (9:1, v/v) was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 × 100 mm, 1.7 µm) with 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reaction monitoring mode was used for quantification using target fragment ions m/z 416.3 → 98.0 for hupehenine, and m/z 430.3 → 138.2 for IS. Calibration plots were linear throughout the range 2-2000 ng/mL for hupehenine in rat plasma. Mean recoveries of hupehenine in rat plasma ranged from 92.5 to 97.3%. Relative standard deviations of intra-day and inter-day precision were both <6%. The accuracy of the method was between 92.7 and 107.4%. The method was successfully applied to a pharmacokinetic study of hupehenine after either oral or intravenous administration. For the first time, the bioavailability of hupehenine was reported as 13.4%. PMID:26033449

  11. 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. PMID:26864353

  12. Large area cold plasma applicator for decontamination

    NASA Astrophysics Data System (ADS)

    Konesky, G. A.

    2008-04-01

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

  13. 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.

  14. Sunitinib LC-MS/MS Assay in Mouse Plasma and Brain Tissue: Application in CNS Distribution Studies.

    PubMed

    Oberoi, Rajneet K; Mittapalli, Rajendar K; Fisher, James; Elmquist, William F

    2013-12-01

    Sunitinib malate is a multi-targeted tyrosine-kinase inhibitor, currently in clinical trials for glioma. Previously developed methods for preclinical studies in species such as mice have either employed high-performance liquid chromatography (HPLC) or did not describe a detailed analytical method, which could be employed by other preclinical laboratories. In this paper, we have developed and validated a simple, sensitive high-performance liquid chromatography tandem mass-spectrometric method (LC-MS/MS) for the determination of sunitinib concentration in mouse plasma and brain tissue homogenate using dasatinib-free base as the internal standard. A single step liquid-liquid extraction method was used for both the matrices. Since sunitinib exhibits light-induced E/Z isomerism, all sample preparation was done in light-protected conditions. Separation was performed on a ZORBAX Eclipse XDB C18 column 4.6 × 50 mm, 1.8 μm. The mobile phase consisted of 20 mM ammonium formate (with 0.1 % formic acid): acetonitrile (70:30, v/v) pumped isocratically at a flow rate of 0.25 mL min(-1) with a total run-time of 13 min. The retention times of sunitinib and dasatinib were 7.8 and 5.5 min, respectively. The calibration curve was linear over the range from 1.95 to 500 ng mL(-1) in both plasma and brain tissue homogenate with 1.95 ng mL(-1) as the lower limit of quantification (LLOQ) for both the matrices. Inter- and intra-day accuracy and precision was <15 % for low QC, med QC and high QC and <20 % for LLOQ. The method was applied to a pharmacokinetic study in FVB wild-type mice to determine the plasma and brain concentrations after a single oral sunitinib malate dose of 20 mg kg(-1). PMID:24409000

  15. 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

  16. Quantification of roxatidine in human plasma by liquid chromatography electrospray ionization tandem mass spectrometry: application to a bioequivalence study.

    PubMed

    Ryu, Ju-Hee; Choi, Sang-Jun; Lee, Heon-Woo; Choi, Seung-Ki; Lee, Kyung-Tae

    2008-12-01

    A sensitive and specific method using a one-step liquid-liquid extraction (LLE) with ethyl acetate followed by high-performance liquid chromatography (HPLC) coupled with positive ion electrospray ionization tandem mass spectrometry (ESI-MS/MS) detection was developed and validated for the determination of roxatidine in human plasma using famotidine as an internal standard (IS). Data acquisition was carried out in multiple reaction monitoring (MRM) mode, by monitoring the transitions m/z 307.3-->107.1 for roxatidine and m/z 338.4-->189.1 for famotidine. Chromatographic separation was performed on a reverse phase Hydrosphere C(18) column at 0.2 mL min(-1) using a mixture of methanol-ammonium formate buffer as mobile phase (20:80, v/v; adjusted to pH 3.9 with formic acid). The achieved lower limit of quantification (LLOQ) was 1.0 ng mL(-1) and the standard calibration curve for roxatidine was linear (r(2)=0.998) over the studied range (1-1000 ng mL(-1)) with acceptable accuracy and precision. Roxatidine was found to be stable in human plasma samples under short-, long-term storage and processing conditions. The developed method was validated and successfully applied to the bioequivalence study of roxatidine administrated as a single oral dose (75 mg as roxatidine acetate hydrochloride) to healthy female Korean volunteers. PMID:18977187

  17. Simultaneous determination of mangiferin and neomangiferin in rat plasma by UPLC-MS/MS and its application for pharmacokinetic study.

    PubMed

    Qiu, Xiangjun; Zhao, Jian-Long; Hao, Cong; Yuan, Canli; Tian, Nuan; Xu, Zhi-Sheng; Zou, Ruan-Min

    2016-05-30

    In this study, a sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine mangiferin and neomangiferin in rat plasma simultaneously. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a Xevo TQD triple quadruple mass spectrometer coupled with an electrospray ionization (ESI) source. The MRM transitions of m/z 423.2→303.1 and m/z 585.0→273.1 were used to quantify for mangiferin and neomangiferin, respectively. The linearity of this method was found to be within the concentration range of 5-2000ng/mL for mangiferin, and 2-1000ng/mL for neomangiferin in rat plasma, respectively. Only 3.0min was needed for an analytical run. This assay was used to support a preclinical study to investigate the pharmacokinetics of mangiferin and neomangiferin in rats. PMID:26945635

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

    PubMed

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

    2016-09-01

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

  19. 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

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

    PubMed

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

    2016-01-01

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

  1. 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

  2. Application of Dusty Plasmas for Space

    NASA Astrophysics Data System (ADS)

    Bhavasar, Hemang; Ahuja, Smariti

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

  3. A quantitative determination of fluorochloridone in rat plasma by UPLC-MS/MS method: application to a pharmacokinetic study.

    PubMed

    Liu, Shihong; Shi, Jingmin; Fan, Junpei; Sun, Jie; Zhang, Suhui; Hu, Yue; Wei, Li; Wu, Chunhua; Chang, Xiuli; Tang, Liming; Zhou, Zhijun

    2016-08-01

    A precise, high-throughput and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed for the determination of fluorochloridone (FLC) in rat plasma. The extraction of analytes from plasma samples was carried out by protein precipitation procedure using acetonitrile prior to UPLC-MS/MS analysis. Verapamil was proved as a proper internal standard (IS) among many candidates. The chromatographic separation based on UPLC was well optimized. Multiple reaction monitoring in positive electrospray ionization was used with the optimized MS transitions at: m/z 312.0 → 292.0 for FLC and m/z 456.4 → 165.2 for IS. This method was well validated with good linear response (r(2)  > 0.998) observed over the investigated range of 3-3000 ng/mL and with satisfactory stability. This method was also characterized with adequate intra- and inter-day precision and accuracy (within 12%) in the quality control samples, and with high selectivity and less matrix effect observed. Total running time was only 1.5 min. This method has been successfully applied to a pilot FLC pharmacokinetic study after oral administration. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26663256

  4. Quantitative determination of euphol in rat plasma by LC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Xie, Xu; Li, Yongning; Gao, Dongna; Zhang, Yu; Ren, Yanbo

    2014-09-01

    Euphol is a potential pharmacologically active ingredient isolated from Euphorbia kansui. A simple, rapid, and sensitive method to determine euphol in rat plasma was developed based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the first time. The analyte and internal standard (IS), oleanic acid, were extracted from plasma with methanol and chromatographied on a C18 short column eluted with a mobile phase of methanol–water–formic acid (95:5:0.1, v/v/v). Detection was performed by positive ion atmospheric pressure chemical ionization in selective reaction monitoring mode. This method monitored the transitions m/z 409.0 →109.2 and m/z 439.4 → 203.2 for euphol and IS, respectively. The assay was linear over the concentration range 27–9000 ng/mL, with a limit of quantitation of 27 ng/mL. The accuracy was between –7.04 and 4.11%, and the precision was <10.83%. This LC-MS/MS method was successfully applied to investigate the pharmacokinetic study of euphol in rats after intravenous (6 mg/kg) and oral (48 mg/kg) administration. Results showed that the absolute bioavailability of euphol was approximately 46.01%. PMID:25237707

  5. The role and application of ion beam analysis for studies of plasma-facing components in controlled fusion devices

    NASA Astrophysics Data System (ADS)

    Rubel, Marek; Petersson, Per; Alves, Eduardo; Brezinsek, Sebastijan; Coad, Joseph Paul; Heinola, Kalle; Mayer, Matej; Widdowson, Anna

    2016-03-01

    First wall materials in controlled fusion devices undergo serious modification by several physical and chemical processes arising from plasma-wall interactions. Detailed information is required for the assessment of material lifetime and accumulation of hydrogen isotopes in wall materials. The intention of this work is to give a concise overview of key issues in the characterization of plasma-facing materials and components in tokamaks, especially in JET with an ITER-Like Wall. IBA techniques play a particularly prominent role here because of their isotope selectivity in the low-Z range (1-10), high sensitivity and combination of several methods in a single run. The role of 3He-based NRA, RBS (standard and micro-size beam) and HIERDA in fuel retention and material migration studies is presented. The use of tracer techniques with rare isotopes (e.g. 15N) or marker layers on wall diagnostic components is described. Special instrumentation, development of equipment to enhance research capabilities and issues in handling of contaminated materials are addressed.

  6. Method development and validation of almotriptan in human plasma by HPLC tandem mass spectrometry: application to pharmacokinetic study.

    PubMed

    Ravikumar, Konda; Chandu, Babu Rao; Challa, Balasekhara Reddy; Chandrasekhar, Kottapalli B

    2012-06-01

    A simple, sensitive and selective method has been developed for quantification of Almotriptan (AL) in human plasma using Almotriptan-d(6) (ALD6) as an internal standard. Almotriptan and Almotriptan-d(6) were detected with proton adducts at m/z 336.1→201.1 and 342.2→207.2 in multiple reaction monitoring (MRM) positive mode, respectively. The method was linear over a concentration range of 0.5-150.0 ng/mL. The limit of detection (LOD) and limit of quantification (LOQ) for Almotriptan were 0.2 pg/mL and 0.5 ng/mL, respectively. Liquid-liquid extraction was used followed by MS/MS (ion spray). The method was shown to be precise with an average within-run and between-run variation of 0.68 to 2.78% and 0.57 to 0.86%, respectively. The average within-run and between-run accuracy of the method throughout its linear range was 98.94 to 102.64% and 99.43 to 101.44%, respectively. The mean recovery of drug and internal standard from human plasma was 92.12 ± 4.32% and 89.62 ± 6.32%. It can be applied for clinical and pharmacokinetic studies. PMID:22896823

  7. Method Development and Validation of Almotriptan in Human Plasma by HPLC Tandem Mass Spectrometry: Application to Pharmacokinetic Study

    PubMed Central

    Ravikumar, Konda; Chandu, Babu Rao; Challa, Balasekhara Reddy; Chandrasekhar, Kottapalli B.

    2012-01-01

    A simple, sensitive and selective method has been developed for quantification of Almotriptan (AL) in human plasma using Almotriptan-d6 (ALD6) as an internal standard. Almotriptan and Almotriptan-d6 were detected with proton adducts at m/z 336.1→201.1 and 342.2→207.2 in multiple reaction monitoring (MRM) positive mode, respectively. The method was linear over a concentration range of 0.5–150.0 ng/mL. The limit of detection (LOD) and limit of quantification (LOQ) for Almotriptan were 0.2 pg/mL and 0.5 ng/mL, respectively. Liquid-liquid extraction was used followed by MS/MS (ion spray). The method was shown to be precise with an average within-run and between-run variation of 0.68 to 2.78% and 0.57 to 0.86%, respectively. The average within-run and between-run accuracy of the method throughout its linear range was 98.94 to 102.64% and 99.43 to 101.44%, respectively. The mean recovery of drug and internal standard from human plasma was 92.12 ± 4.32% and 89.62 ± 6.32%. It can be applied for clinical and pharmacokinetic studies. PMID:22896823

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

    PubMed

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

    2008-11-01

    A rapid, simple and sensitive LC-MS/MS method was developed for simultaneous determination of amoxicillin and ambroxol in human plasma using clenbuterol as internal standard (IS). The plasma samples were subjected to a simple protein precipitation with methanol. Separation was achieved on a Lichrospher C(18) column (150 mm x 4.6mm ID, dp 5 microm) using methanol (containing 0.2% of formic acid) and water (containing 0.2% of formic acid) as a mobile phase by gradient elution at a flow rate of 1.0 mL/min. Detection was performed using electrospray ionization in positive ion multiple reaction monitoring (MRM) mode by monitoring the ion transitions from m/z 365.9-->348.9 (amoxicillin), m/z 378.9-->263.6 (ambroxol) and m/z 277.0-->203.0 (IS). Calibration curves were linear in the concentration range of 5-20,000 ng/mL for amoxicillin, and 1-200 ng/mL for ambroxol, with the intra- and inter-run precisions of <9% and the accuracies of 100+/-7%. The method has been validated and applied to pharmacokinetic studies of compound amoxicillin and ambroxol hydrochloride tablets in healthy Chinese volunteers. PMID:18603398

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

    PubMed

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

    2015-04-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS-MS) method for the determination of rutin in rat plasma was developed and validated. After addition of tolbutamide as internal standard (IS), protein precipitation by acetonitrile was used as sample preparation. The chromatographic separation was performed on an Acquity UPLC BEH C18 column (2.1 × 50 mm, 1.7 μm particle size), using acetonitrile-0.1% formic acid as the mobile phase with gradient elution, delivered at a flow-rate of 0.4 mL/min. Mass spectrometric analysis was performed using a XEVO TQD mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 610.91→302.98 and m/z 271.2→155.1 were used to quantify for rutin and tolbutamide, respectively. This assay method has been fully validated in terms of specificity, linearity, recovery and matrix effect, accuracy, precision and stability. Calibration curves were linear in the concentration ranges of 25-2000 ng/mL for rutin. Only 3 min was needed for an analytical run. This developed method was successfully used for determination of rutin in rat plasma for pharmacokinetic study. PMID:25030991

  10. A simple LC-MS method for determination of cyasterone in rat plasma: application to a pilot pharmacokinetic study.

    PubMed

    Li, Fuqiang; Li, Guangyu; Zhao, Jinsong; Xiao, Jun; Liu, Zaoxia; Su, Guanfang

    2016-06-01

    A simple, specific, and sensitive liquid chromatography-mass spectrometry (LC-MS) method for determination of cyasterone in rat plasma was developed in our laboratory. Cucurbitacin B was used as an internal standard (IS). After protein precipitation with twofold volume of acetonitrile, the analyte and IS were separated on a Luna C18 column (100 × 4.6 mm, i.d., 3.0 µm; Phenomenex) by isocratic elution with acetonitrile-water (80:20, v/v) as the mobile phase at a flow rate of 0.4 mL/min. An electrospray ionization source was applied and operated in the positive ion mode; selected ion monitoring scan mode was used for quantification, and the target ions m/z 543.3 for cyasterone and m/z 581.3 for IS were chosen. Good linearity was observed in the concentration range of 0.40-400 ng/mL for cyasterone in rat plasma. Intra-day and inter-day precision were both <7.4%. This method was proved to be suitable for pharmacokinetic studies after oral (5.0 mg/kg) or intravenous (0.5 mg/kg) administration of cyasterone in rats. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26390114

  11. Quantification of complanatoside A in rat plasma using LC-MS/MS and its application to a pharmacokinetic study.

    PubMed

    Li, Nan; Liu, Yue; Cao, Yuchen; Wei, Zhouxia; Pang, Li; Wang, Jianmeng

    2016-06-01

    Complanatoside A is a flavonol glycoside isolated from Astragalus complanatus, and currently it is used as a quality control index for A. complanatus in the 2010 edition of the Chinese Pharmacopoeia. For the first time, a simple and sensitive LC-MS/MS method was developed for the determination of complanatoside A in rat plasma over the range of 2.3-575 ng/mL. Complanatoside A was extracted from plasma by a protein precipitation procedure, separated by LC and detected by MS/MS in positive electrospray ionization mode. The method was validated for selectivity, carryover, sensitivity, linearity, extraction recovery, matrix effect, accuracy, precision and stability studies. The lower limit of quantification was established at 2.3 ng/mL. Intra- and inter-day precisions (LLOQ, low-QC, med-QC and high-QC) were <7.9%, and accuracies were between 94.0 and 105.1%. Matrix effect was acceptable (97.9-103.0%) and extraction recovery was reproducible (88.5-94.4%). Complanatoside A was stable in the investigated conditions. The method was applied to the pharmacokinetics of complanatoside A in rats. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26393341

  12. 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.

  13. Liquid chromatography mass spectrometry simultaneous determination of vindoline and catharanthine in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Lin, Chongliang; Cai, Jinzhang; Yang, Xuezhi; Hu, Lufeng; Lin, Guanyang

    2015-01-01

    Vinblastine and vincristine, both of which are bisindole alkaloids derived from vindoline and catharanthine, have been used for cancer chemotherapy; their monomeric precursor molecules are vindoline and catharanthine. A simple and selective liquid chromatography mass spectrometry method for simultaneous determination of vindoline and catharanthine in rat plasma was developed. Chromatographic separation was achieved on a C18 (2.1 × 50 mm, 3.5 µm) column with acetonitrile-0.1% formic acid in water as mobile phase with gradient elution. The flow rate was set at 0.4 mL/min. An electrospray ionization source was applied and operated in positive ion mode; selective ion monitoring mode was used for quantification. Mean recoveries were in the range of 87.3-92.6% for vindoline in rat plasma and 88.5-96.5% for catharanthine. Matrix effects for vindoline and catharanthine were measured to be between 95.3 and 104.7%. Coefficients of variation of intra-day and inter-day precision were both <15%. The accuracy of the method ranged from 93.8 to 108.1%. The method was successfully applied in a pharmacokinetic study of vindoline and catharanthine in rats. The bioavailability of vindoline and catharanthine were 5.4 and 4.7%, respectively. PMID:24828449

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

    PubMed

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

    2015-01-01

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

  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. PMID:26277443

  16. Radio-frequency Plasma Sheath Studies

    NASA Astrophysics Data System (ADS)

    Hicks, Nathaniel

    2015-09-01

    The response of ion-electron plasma as well as two-component plasma to RF fields is studied via PIC simulation. In each case, the light species responds strongly to the RF and the heavy species does not. By varying the external electrode geometry, RF waveform, and driving voltage and frequency, light species of certain charge-to-mass ratios may experience a trapping effect within the RF structure. The space charge of this species creates a potential well for the oppositely-charged, heavy species. Simulation results are presented, as well as plans for experimental investigation of the same effect. Applications to plasma processes in which a plasma boundary is subjected to external RF fields are discussed.

  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. PMID:23836529

  18. 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.

  19. Computational comparative study of microwave probes for plasma density measurement

    NASA Astrophysics Data System (ADS)

    Kim, D. W.; You, S. J.; Kim, J. H.; Chang, H. Y.; Oh, W. Y.

    2016-06-01

    A microwave probe is known to be a suitable method to measure plasma density, even in the processing condition and is widely used in various environments of low-temperature processing plasmas. Various types of microwave probes have been researched and developed to measure the precise plasma density. Extensive research has been conducted to investigate each probes characteristic responding to the plasma parameters (plasma density, electron temperature, pressure, sheath width, and so forth) based on both experiments and simulations. However, a comparative study elucidating the relative characteristics of each probe has not been completed yet, despite the wide applications of the probes in processing plasma. We conduct a comparative study among the microwave probes using the numerical method of three-dimensional finite-difference time-domain simulation. In this study, the microwave probes are compared by investigating the precision of plasma density measurement under a comprehensive range of plasma parameters (plasma density, pressure, and sheath width).

  20. Computational studies of nonlinear dispersive plasma systems

    NASA Astrophysics Data System (ADS)

    Qian, Xin

    Plasma systems with dispersive waves are ubiquitous. Dispersive waves have the property that their wave velocity depends on the wave number of the wave. These waves show up in weakly as well as strongly coupled plasmas, and play a significant role in the underlying plasma dynamics. Dispersive waves bring new challenges to the computer simulation of nonlinear phenomena. The goal of this thesis is to discuss two computational studies of plasma phenomena, one drawn from strongly coupled complex or dusty plasmas, and the other from weakly coupled hydrogen plasmas. In the realm of dusty plasmas, we focus on the problem of three-dimensional (3D) Mach cones which we study by means of Molecular Dynamics (MD) simulations, assuming that the dust particles interact via a Yukawa potential. While laboratory and MD simulations have explored thoroughly the properties of Mach cones in 2D, elucidating the important role of dispersive waves in the formation of multiple cones, the simulations presented in this thesis represent the first 3D MD studies of Mach cones in strongly coupled dusty plasmas. These results have qualitative similarities with experimental observations on 3D Mach cones from the PK-3 plus project, which studies complex plasmas under microgravity conditions aboard the International Space station. In the realm of weakly coupled plasmas, we present results on the application of non-oscillatory central schemes to Hall MHD reconnection problems, in which the presence of dispersive whistler waves presents a formidable challenge for numerical algorithms that rely on explicit time-stepping schemes. In particular, we focus on the semi-discrete central formulation of Kurganov and Tadmor (2000), which has the advantage that it allow for larger time steps, and with significantly smaller numerical viscosity, than fully discrete schemes. We implement the Hall MHD equations through the CentPACK software package that implements the Kurganov-Tadmor formulation for a wide range of

  1. 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. PMID:21740373

  2. 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. PMID:27336702

  3. Simultaneous quantification of hyperin, reynoutrin and guaijaverin in mice plasma by LC-MS/MS: application to a pharmacokinetic study.

    PubMed

    Li, Z; Meng, F; Zhang, Y; Sun, L; Yu, L; Zhang, Z; Peng, S; Guo, J

    2016-07-01

    A specific and sensitive LC-MS/MS assay was developed to simultaneously quantify three structurally similar flavonoid glycosides - hyperin, reynoutrin and guaijaverin - in mouse plasma. Biosamples were prepared by solid-phase extraction. Isocratic chromatographic separation was performed on an AichromBond-AQ C18 column (250 × 2.1 mm, 5 μm) with methanol-acetonitrile-water-formic acid (20:25:55:0.1) as the mobile phase. Detection of hyperin, reynoutrin, guaijaverin and internal standard [luteolin-7-O-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranoside] was achieved by ESI-MS/MS in the negative ion mode using m/z 463 → m/z 300, m/z 433 → m/z 300, m/z 433 → m/z 300 and m/z 579 → m/z 285 transitions, respectively. Linear concentration ranges of calibration curves were 4.0-800.0 ng/mL for hyperin and reynoutrin and 8.0-1600.0 ng/mL for guaijaverin when 100 μL of plasma was analyzed. We used this validated method to study the pharmacokinetics of hyperin, reynoutrin and guaijaverin in mice following oral and intravenous administration. All three quercetin-3-O-glycosides showed poor oral absorption in mice, and the absolute bioavailability of hyperin after oral administration of 100 mg/kg was 1.2%. Pretreatment with verapamil increased the peak concentration and area under the concentration-time curve of hyperin, which were significantly higher than the control values. The half-life of hyperin with verapamil was significantly prolonged compared with that of the control. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26588877

  4. Dense Hypervelocity Plasma Jets for Fusion Applications

    NASA Astrophysics Data System (ADS)

    Witherspoon, F. Douglas; Thio, Y. C. Francis

    2005-10-01

    High velocity dense plasma jets are being developed for a variety of fusion applications, including refueling, disruption mitigation, High Energy Density Plasmas, magnetized target/magneto-inertial fusion, injection of angular momentum into centrifugally confined mirrors, and others. The technical goal is to accelerate plasma blobs of density >10^17 cm-3 and total mass >100 micrograms to velocities >200 km/s. The approach utilizes symmetrical injection of very high density plasma into a coaxial EM accelerator having a tailored cross-section that prevents formation of the blow-by instability. AFRL MACH2 modeling identified 2 electrode configurations that produce the desired plasma jet parameters. The injected plasma is generated by up to 64 radially oriented capillary discharges arranged uniformly around the circumference of an angled annular injection section. Initial experimental results are presented in which 8 capillaries are fired in parallel with jitter of ˜100 ns. Current focus is on higher voltage operation to reduce jitter to a few 10's of ns, and development of a suite of optical and spectroscopic plasma diagnostics.

  5. 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.

  6. Development of a liquid chromatography with mass spectrometry method for the determination of gelsemine in rat plasma and tissue: Application to a pharmacokinetic and tissue distribution study.

    PubMed

    Zhang, Shuangshuang; Hu, Shuping; Yang, Xiangxiang; Shen, Jiaqi; Zheng, Xiaoyong; Huang, Kexin; Xiang, Zheng

    2015-03-01

    Gelsemine from Gelsemium elegans Benth is a potential anesthetic and analgesic agent with no physical dependence and opiate addiction. This study was aimed at developing an ultrafast liquid chromatography coupled to tandem mass spectrometry method to quantify gelsemine in rat plasma and tissues. Plasma and tissues were processed with acetonitrile precipitation, and dendrobine was chosen as the internal standard. Sample separation was performed on an ACQUITY HSS T3 column. The mobile phase consisted of acetonitrile and 0.1% formic acid aqueous solution. Multiple reactions monitoring mode was utilized to detect the compounds of interest. The mass spectrometer was operated in the positive ion mode for detection. The MS/MS ion transitions monitored were m/z 323.2→70.5 for gelsemine and 264.2→108.05 for dendrobine, respectively. The calibration curves were linear over the range of 1-500 ng/mL in all biological matrices. The lower limit of quantification for rats plasma and tissues was 1.0 ng/mL. The values for inter- and intraday precision and accuracy were well within the ranges acceptable (< 15%). It was successfully applied to the pharmacokinetic and tissue distribution studies of gelsemine after intravenous doses of 5, 2, and 0.5 mg/kg in rats. These data of gelsemine would be useful for clinical application and further development. PMID:25580713

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

    PubMed

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

    2015-04-01

    Prescription and nonprescription products for topical management of pain, including cream, lotion and patch forms, contain capsaicin (CAP) and dihydrocapsaicin (DHC). There are few in vivo studies on absorption, bioavailability and disposition of CAP and DHC. We established a sensitive and rapid LC-MS/MS assay to determine CAP and DHC levels in rabbit plasma and tissue. Bio-samples prepared by liquid-liquid extraction using n-hexane-dichloromethane-isopropanol (100: 50: 5, v/v/v) mixture were separated by isocratic chromatography with an Extend C18 column. The mobile phase was acetonitrile-water-formic acid (70: 30: 0.1, v/v/v). The method was linear from 0.125 to 50 ng/mL for a 100 μL bio-sample, and the lower quantification limit was 0.125 ng/mL. Total run time to analyze each sample was 3.5 min. We used this validated method to study pharmacokinetics and tissue distribution of CAP gel administered topically to rabbits. A very small amount of CAP and DHC was absorbed into the systemic circulation. The highest plasma concentration was 2.39 ng/mL, and the mean peak plasma concentration value after 12 h of CAP gel application was 1.68 ng/mL. Drug concentration in treated skin was relatively high, with low concentration in other tissues. Thus, topical CAP gel had strong local effects and weaker systemic effects. PMID:25088519

  8. A sensitive LC-MS/MS method to quantify methylergonovine in human plasma and its application to a pharmacokinetic study.

    PubMed

    Gao, Yanhui; Sun, Qichao; Liu, Dongming; Ma, Bowen; Zhao, Hengli; Fang, Zengjun; Wang, Haisheng; Lou, Hongxiang

    2016-02-01

    Methylergonovine (ME) is a semisynthetic ergot alkaloid that is used for the treatment and prophylaxis of postpartum hemorrhage. In recent years, methylergonovine has been effective in the control of refractory headaches and is likely to be employed as chemosensitizers for cancer. However, this alkaloid sometimes causes elevated blood pressure. Therefore, a sensitive and accurate method for the quantification of this drug in biological matrices is necessary. In this study, ME was extracted from 500μL plasma samples by a liquid-liquid extraction under alkaline conditions and detected using positive multi-reaction-monitoring mode (+MRM) mass spectrometry. The method was validated according to US FDA guidelines and covered a working range from 0.025 to 10ng/mL with a lower limit of quantification (LLOQ) of 0.025ng/mL. In conclusion, a rapid, sensitive, selective and accurate quantification by an LC-MS/MS method was developed and successfully applied to a clinical pharmacokinetics study in female volunteers after a single intramuscular injection or oral administration of a 0.2mg dose of ME maleate. It is suitable for both preclinical and clinical studies on ME. PMID:26760224

  9. Current new applications of laser plasmas

    SciTech Connect

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

    1988-09-01

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

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

    PubMed

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

    2015-05-01

    1-Triacontanol (TA), a member of long chain fatty alcohol, has recently been received great attention owing to its antitumor activity. In this study, an accurate, sensitive and selective gas chromatography-tandem mass spectrometry method was developed and validated for the quantification of TA in beagle plasma using 1-octacosanal as the internal standard (IS) for the first time. With temperature programming, chromatographic separation was carried out on an HP-5MS column, using helium as carrier gas and argon as collision gas, both at a flow rate of 1 mL/min. TA was analyzed using positive ion electrospray ionization in multiple-reaction monitoring mode, with the precursor to product ion transitions of m/z 495.6 → 97.0 and m/z 467.5 → 97.0 for TA and the IS, respectively. The lower limit of quantitation, linearity, intra- and interday precision, accuracy, stability, extraction recovery and matrix effect of TA were within the acceptable limits. The validated method was successfully applied to a pharmacokinetic study of TA in beagles. PMID:25331188

  11. 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...

  12. Spectroscopy of Z-pinch plasmas: how atomic and plasma physics merge and unfold new applications

    NASA Astrophysics Data System (ADS)

    Safronova, Alla

    2012-06-01

    Recent advances in theoretical and experimental work on plasma spectroscopy of Z-pinches are presented. We have shown that the University-scale Z-pinch generators are able to produce plasmas within a broad range of temperatures, densities, opacity, and radiative properties depending on the type, geometry, size, and mass of wire array loads and wire material. The full x-ray and EUV diagnostic set for detailed spatial and temporal monitoring of such a plasma together with relativistic atomic and non-LTE kinetic codes create a very useful and productive environment for the study of atomic and plasma spectroscopy features and development of their applications. A variety of examples of K-shell low-Z (such as Mg and Al), L-shell mid-Z (such as Ni, Cu, and Ag), and M- and L-shell high-Z (W) will be considered and their specific features and applications to fusion and astrophysics will be highlighted.

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Ticoş, Cǎtǎlin 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.

  15. 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. PMID:25459927

  16. Plasmas as Antennas - Theory, Experiment and Applications

    NASA Astrophysics Data System (ADS)

    Borg, Gerard

    1999-11-01

    A variety of antennas are employed in telecommunications and radar systems. Some applications pose special problems. Large structures are easily detected by hostile radar. The performance of multi-element HF-VHF arrays is complicated by mutual coupling between large radiating elements. High speed data communications and radar can be limited by signal decay and ringing. A novel solution is an antenna made of plasma that can be made to disappear on microsecond time scales. Recent experiments at the Australian National University (G.G. Borg et. al. App. Phys. Letts. Vol. 74, 3272-3274 [1999]), have shown that highly efficient (25 - 50radiating elements for the range 3 - 300 MHz can be formed using low power (10 - 50 W average) plasma surface waves launched at one end of a tube containing a suitable gas. Only a single capacitive coupler is needed to launch the waves - there is no electrical connection to the other end of the tube. The regimes of wave propagation correlate with expectations from plasma surface wave theory. Actual communications experiments have shown that these plasma antennas can have surprisingly low noise provided they are excited by the rf surface waves and not by a low frequency or DC ohmic current. Applications to HF-VHF communications and radar are being developed. These include both single ruggedised plasma elements and multi-element arrays.

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

    PubMed

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

    2015-04-10

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

  18. 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. PMID:26324195

  19. Determination of ulixertinib in mice plasma by LC-MS/MS and its application to a pharmacokinetic study in mice.

    PubMed

    Kumar, Rajinish; Suresh, P S; Rudresh, G; Zainuddin, Mohd; Dewang, Purushottam; Kethiri, Ragahava Reddy; Rajagopal, Sriram; Mullangi, Ramesh

    2016-06-01

    A sensitive, specific and rapid LC-ESI-MS/MS method has been developed and validated for the quantification of ulixertinib in mice plasma using phenacetin as an internal standard (I.S.) as per regulatory guidelines. Sample preparation was accomplished through a protein precipitation procedure with acetonitrile:methanol mixture. Chromatographic separation was performed on Atlantis dC18 column using a binary gradient using mobile phase A (0.2% formic acid in water) and B (acetonitrile) at a flow rate of 0.60mL/min. Elution of ulixertinib and I.S. occurred at ∼1.07 and 1.20min, respectively. The total chromatographic run time was 2.5min. A linear response function was established in the concentration range of 1.58-2054ng/mL. The intra- and inter-day accuracy and precisions were in the range of 2.11-11.8 and 5.80-11.4%, respectively. This novel method has been applied to a pharmacokinetic study in mice. PMID:27017572

  20. Validated LC-MS/MS Assay for the Quantitative Determination of Fimasartan in Human Plasma: Application to Pharmacokinetic Studies.

    PubMed

    Yoon, Seo Hyun; Oh, Seul; Kim, Hwa Suk; Yi, SoJeong; Yu, Kyung-Sang; Jang, In-Jin; Cho, Joo-Youn

    2015-09-01

    A simple, rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of a newly developed antihypertensive agent fimasartan (BR-A657, Kanarb(®)) in human plasma was developed and validated. Fimasartan and internal standard (IS, BR-A563) were extracted by simple protein precipitation using acetonitrile and separated on a Phenyl-Hexyl column (Luna(®), 5 µm, 50 mm × 2.0 mm, Phenomenex) under the gradient conditions of mobile phase A (distilled water with 0.1% formic acid) and mobile phase B (100% acetonitrile with 0.1% formic acid) at a flow rate of 0.25 mL/min. Detection and quantification were performed by the mass spectrometer using multiple reaction monitoring mode at m/z 500.2 → 221.2 for fimasartan and m/z 524.3 → 204.9 for the IS. The assay was linear over a calibration range of 0.5-500 ng/mL with a lower limit of quantification of 0.5 ng/mL. The coefficient of variation of this assay precision was <14.9% and the accuracy exceeded 91.9%. This method provided the necessary sensitivity, linearity, precision, accuracy and specificity to allow the determination of fimasartan after oral administration to healthy Korean male volunteers in several drug-drug interaction studies conducted at the Clinical Trials Center of Seoul National University Hospital. PMID:25616988

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

    PubMed

    Wang, Zhe; Huang, Cheng-ke; Sun, Wei; Xiao, Cui; Wang, Zeng-shou

    2015-02-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine voriconazole in human plasma. Sample preparation was accomplished through a simple one-step protein precipitation with methanol. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column using an isocratic mobile phase system composed of acetonitrile and water containing 1% formic acid (45:55, v/v) at a flow rate of 0.50 mL/min. Mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The multiple reaction monitoring transitions of m/z 351.0 → 281.5 and m/z 237.1 → 194.2 were used to quantify voriconazole and carbamazepine (internal standard), respectively. The linearity of this method was found to be within the concentration range of 2.0-1000 ng/mL with a lower limit of quantification of 2.0 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 200 mg voriconazole to 20 Chinese healthy male volunteers. PMID:24925071

  2. Laboratory and Space Plasma Studies

    NASA Astrophysics Data System (ADS)

    Hyman, Ellis

    1996-08-01

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

  3. Study of the SEE decay processes in application to mechanisms of dissipation of the HF plasma turbulence and diagnostics of the ionospheric plasma parameters

    NASA Astrophysics Data System (ADS)

    Sergeev, Evgeny

    Results of the investigations of the decay process for different stimulated electromagnetic emission (SEE) features at the SURA heating facility (Russia) are presented. The data of the measurements are used to analyze the nonlinear energy transformation through the spectra of the Langmuir and upper hybrid plasma turbulence as well as to determine a relationship between the electron collision frequency and the collisionless decay rate of the plasma waves under different ionospheric conditions. In particular, due to the SEE decay time measurements at the upper hybrid turbulence development stage it is found an increase of the decay rate γ of the emission from the collision values γ = τ -1 = 300 - 400 s-1 to the collisionless values γ = 2000 - 10000 s-1 in a wide frequency band (up to 600 kHz) near the 4th - 7th cyclotron electron gyroharmonics. On the other hand, the SEE decay times didn't found any dependence on the pump power but they slightly increase under change from day to night condition. The results of the daily SEE decay rate monitoring in dependence on the pumping frequency (re- flection altitude) are presented. The work was supported by RFBR grants 07-02-00464 and 06-02-17334.

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

    SciTech Connect

    Macheret, Sergey

    2005-05-16

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

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

    NASA Astrophysics Data System (ADS)

    Macheret, Sergey

    2005-05-01

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

  6. 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.

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

    PubMed

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

    2016-03-01

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

  8. Laser-Induced Underwater Plasma And Its Spectroscopic Applications

    SciTech Connect

    Lazic, Violeta

    2008-09-23

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

  9. Diagnostics and biomedical applications of radiofrequency plasmas

    NASA Astrophysics Data System (ADS)

    Lazović, Saša

    2012-11-01

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

  10. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

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

    2016-01-01

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

  11. Quantification of nimesulide in human plasma by high-performance liquid chromatography/tandem mass spectrometry. Application to bioequivalence studies.

    PubMed

    Barrientos-Astigarraga, R E; Vannuchi, Y B; Sucupira, M; Moreno, R A; Muscará, M N; De Nucci, G

    2001-12-01

    A method based on liquid chromatography with negative ion electrospray ionization and tandem mass spectrometry is described for the determination of nimesulide in human plasma. Liquid-liquid extraction using a mixture of diethyl ether and dichloromethane was employed and celecoxib was used as an internal standard. The chromatographic run time was 4.5 min and the weighted (1/x) calibration curve was linear in the range 10.0-2000 ng x ml(-1). The limit of quantification was 10 ng x ml(-1), the intra-batch precision was 6.3, 2.1 and 2.1% and the intra-batch accuracy was 3.2, 0.3 and 0.1% for 30, 300 and 1200 ng x ml(-1) respectively. The inter-batch precision was 2.3, 2.8 and 2.7% and the accuracy was 3.3, 0.3 and 0.1% for 30, 300 and 1200 ng x ml(-1) respectively. This method was employed in a bioequivalence study of one nimesulide drop formulation (nimesulide 50 mg x ml(-1) drop, Medley S/A Indústria Farmacêutica, Brazil) against one standard nimesulide drop formulation (Nisulid, 50 mg x ml(-1) drop, Astra Médica, Brazil). Twenty-four healthy volunteers (both sexes) took part in the study and received a single oral dose of nimesulide (100 mg, equivalent to 2 ml of either formulation) in an open, randomized, two-period crossover way, with a 2-week washout interval between periods. The 90% confidence interval (CI) for geometric mean ratios between nimesulide and Nisulid were 93.1-109.6% for C(max), 87.7-99.8% for AUC(last) and 88.1-99.7% for AUC(0-infinity). Since the 90% CI for the above-mentioned parameters were included in the 80-125% interval proposed by the US Food and Drug Administration, the two formulations were considered bioequivalent in terms of both rate and extent of absorption. PMID:11754119

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  13. LC-MS/MS method development for quantification of busulfan in human plasma and its application in pharmacokinetic study.

    PubMed

    Nadella, Taraka Ramarao; Suryadevara, Vidyadhara; Lankapalli, Sasidhar Reddyvallam; Mandava, Venkata Basaveswara Rao; Bandarupalli, Deepti

    2016-02-20

    A simple, rapid, specific and precise liquid chromatography-tandem mass spectrophotometric (LC-MS/MS) method was developed and validated for quantification of busulfan, in human plasma. busulfan d8 was used as internal standard, added to plasma sample prior to extraction using acetonitrile as a precipitating agent. Chromatographic separation was achieved on phenomenex kinetex C18 column (50mm×2.1mm, 2.6μm) with acteonitrile: 10mM ammonium formate buffer (80:20v/v) as an isocratic mobile phase with a flow rate of 0.5mLmin(-1). Quantitation was performed by transition of 264.1→151.1 (m/z) for busulfan and 272.1→159.1 (m/z) for busulfan d8. The lower limit of quantitation was 0.2ngmL(-1) with a 100μL plasma sample. The concentrations of nine working standards showed linearity between 0.2 and 100ngmL(-1) (r(2)≥0.9986). Chromatographic separation was achieved within 2.0min. The average extraction recoveries of 3quality control concentrations were 92.52% for busulfan and 90.75% for busulfan d8. The coefficient of variation was ≤15% for intra- and inter-batch assays. The developed method was successfully applied for the determination of Busulfan pharmacokinetics after oral administration. PMID:26736033

  14. Determination of pseudoprotodioscin in rat plasma by UPLC-MS/MS: Assay development and application to pharmacokinetic study.

    PubMed

    Liao, Min; Chen, Xiao; Chen, Jiefeng; Liu, Mengping; Wang, Junyi; Chen, Zuanguang; Xie, Zhiyong; Yao, Meicun

    2016-07-15

    An original and sensitive ultraperformance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method for the determination of pseudoprotodioscin (PPD) in rat plasma was developed and validated. Digitoxin was applied as an internal standard. Plasma samples were processed by acetonitrile-mediated plasma protein precipitation and chromatographed using a step gradient program on a C18 column (2.1×50mm i.d., 1.7μm). The mobile phase was comprised of acetonitrile and 0.1mmolL(-1) aqueous lithium acetate mixed with 0.03% formic acid at the flow rate of 0.2mLmin(-1). Multiple reaction monitoring (MRM) transitions were performed for detection and lithium adduct ions were employed with a significant improvement of the response of the analytes in electrospray positive ionization mode. The concentration range of calibration curve was linear over the range 2-5000ngmL(-1). The intra- and inter-day precisions were all less than 11.5% and accuracies were within the range of 94.1-103.5%, and the analytes exhibited no severe matrix effect. The validated method was successfully applied in the pharmacokinetics of PPD after intragastric (50mgkg(-1)) and intravenous (4mgkg(-1)) administration in rats. PPD showed rapid excretion and with bioavailability of simply about 5.7% in rats. PMID:26012509

  15. Electroreflectance and the problem of studying plasma-surface interactions

    SciTech Connect

    Preppernau, B.L.

    1995-12-31

    A long standing problem in low-temperature plasma discharge physics is to understand in detail the mutual interaction of real exposed surfaces (electrodes) with the reactive plasma environment. In particular, one wishes to discern the influence of these surfaces on the plasma parameters given their contributions from secondary electrons and ions. This paper briefly reviews the known surface interaction processes as well as currently available diagnostics to study the interface between plasmas and surfaces. Next comes a discussion describing the application of plasma-modulated electroreflectance to this research and some potential experimental techniques.

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

    PubMed Central

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

    2014-01-01

    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 modifications 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. PMID:25448297

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

    PubMed

    Cai, Li-Jing; Zhang, Jun; Wang, Xiu-Mei; Zhu, R H; Yang, Jian; Zhang, Qi-Zhi; Peng, W X

    2011-12-01

    A solid-phase extraction-liquid chromatographic-tandem mass spectrometry method for the determination of nalbuphine concentrations in human plasma has been developed. Samples (1 mL) were extracted using a Strata™-X solid phase extraction cartridges. Chromatographic separation of nalbuphine and naloxone (internal standard) was achieved on a Phenomenex Kinetex PFP (2.6 μm, 100 A, 100 × 2.1 mm) column using a mobile phase consisting of 0.1% formic acid, 15 mM ammonium acetate in deionized water and acetonitrile (60:40, v/v). The flow rate was 0.3 mL/min and the total run time was 2 min. Detection of the analytes was achieved using positive ion electrospray ionization via multiple reactions monitoring mode. The mass transitions were m/z 358 → 340 for nalbuphine and m/z 328 → 310 for naloxone. The assay was linear over the concentration range 0.50-500.00 ng/mL, with correlation coefficients ≥0.995. The lower limit of quantitation was set at 0.5 ng/mL plasma based on an average signal-to-noise ratio of 44.79. The intra- and inter-day precision was less than 8.07% in terms of relative standard deviation and accuracy ranged from 94.97 to 106.29% at all quality control levels. The method was applied successfully to determine nalbuphine concentrations in human plasma samples obtained from subjects receiving intravenous administration of nalbuphine. The method is rapid, sensitive, selective and directly applicable to human pharmacokinetic studies involving nalbuphine. PMID:21337353

  18. 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. PMID:20033891

  19. A sensitive LC-MS/MS method for the quantitative determination of biflorin in rat plasma and its application to pharmacokinetic studies.

    PubMed

    Yang, Seung Jun; Ryu, Jong Hoon; Jang, Dae Sik; Yang, Liang; Han, Hyo-Kyung

    2015-11-10

    A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric method (LC-MS/MS) was developed for the quantification of biflorin in rat plasma. Using naringin as an internal standard, plasma samples were subjected to a direct protein precipitation process using methanol. Chromatographic separation was achieved on a Gemini C18 column with an isocratic mobile phase consisting of 0.1% formic acid and methanol (50:50, v/v) at a flow rate of 0.5mL/min. Biflorin was analyzed in the multiple reaction monitoring mode with negative electrospray ionization. The precursor/product ion pairs were m/z 353.0/205.0 and m/z 579.0/271.0 for biflorin and the IS, respectively. The calibration curve was linear over the concentration range of 5-2000ng/mL. The intra- and inter-day precision was less than 7.3% and the accuracy ranged from 96.5 to 103.3%. No significant variation was observed in the stability tests. This method was successfully applied to a pharmacokinetic study of biflorin after the intravenous and oral administration of biflorin to rats. The half-life and oral bioavailability of biflorin were determined as 3.4h and 43%, respectively. This is the first report on the quantitative determination of biflorin in rat plasma as well as the pharmacokinetic characterization of biflorin, which should provide a meaningful foundation for further preclinical and clinical applications of biflorin. PMID:26263054

  20. A novel LC-MS/MS method for simultaneous quantification of tenofovir and lamivudine in human plasma and its application to a pharmacokinetic study.

    PubMed

    Matta, Murali Krishna; Burugula, Laxminarayana; Pilli, Nageswara Rao; Inamadugu, Jaswanth Kumar; J V L N, Seshagiri Rao

    2012-10-01

    A new, rapid, sensitive and specific LC-MS/MS method has been developed and validated for the simultaneous quantification of tenofovir and lamivudine in human plasma using abacavir as an internal standard. An API-4000 LC-MS/MS with electrospray ionization was operated in multiple-reaction monitoring mode for the analysis. The analytes were extracted from plasma by solid-phase extraction technique using an Oasis HLB cartridge. The reconstituted samples were chromatographed on a Chromolith ROD speed C(18) column using a mixture of 0.1% formic acid in water and acetonitrile (90:10 v/v) at a flow-rate of 1 mL/min. The method was validated as per the FDA guidelines. The calibration curves were found to be linear in the range of 5-600 ng/mL for tenofovir and 25- 4000 ng/mL for lamivudine. The intra- and inter-day precision and accuracy results were well within the acceptable limits. A run time of 2.8 min consumed for each sample made it possible to analyze more samples per day. The proposed assay method was found to be applicable to a pharmacokinetic study in human male volunteers. PMID:22222724

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

    PubMed

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

    2007-11-01

    Phenazopyridine hydrochloride is a strong analgesic used in the treatment of urinary tract infections. The aim of the present study was to develop a procedure based on gas chromatography-mass spectrometry (GC-MS) for the analysis of phenazopyridine in rat plasma. The method was set up and adapted for the analysis of small biological samples taken from rats. Biological samples were extracted by liquid-liquid extraction. The extraction agent was ethyl acetate. The samples were separated by GC on a DB-5MS analytical column and determined by a quadrupole mass spectrometer detector operated under selected ion monitoring mode. Excellent linearity was found between 0.01 and 1.00 microg/ml (r = 0.9991, n = 9) for plasma samples. The limit of detection (LOD) was 0.3 ng/ml. Within-day and between-day precisions expressed as the relative standard deviation (RSD) for the method were 1.83-4.91% and 2.12-4.76%, respectively. The recoveries for all samples were >90%. The main pharmacokinetic parameters obtained were T(max) = (0.35+/-0.01) h, C(max) = (0.396+/-0.079) microg/ml, AUC = (0.373+/-0.065) h microg/ml and CL = (94.2+/-5.9) ml/g/h. The results presented here clearly indicate that this proposed method could be applicable to investigate the pharmacokinetic of phenazopyridine in rats after administration. (c) PMID:17847064

  2. Liquid Chromatographic Method for Simultaneous Quantitation of Clopidogrel, Aspirin and Atorvastatin in Rat Plasma and Its Application to the Pharmacokinetic Study.

    PubMed

    Porwal, Pawan K; Akhalaque Ahmad, R A; Chhajed, Santosh S; Chatpalliwar, Vivekanand A

    2015-08-01

    A simple and robust analytical reversed-phase high-performance liquid chromatography method was developed and validated for simultaneous chromatographic elution of three cardiovascular drugs, namely clopidogrel, aspirin (ASP) and atorvastatin. The method was developed in rat plasma and dosage formulation with high-quality chromatographic separation between the drug peaks by using a stainless steel analytical column thermo beta-basic, C18 (25 × 0.46 cm, 5 µm). The system was operated at 25°C using a mobile phase consisting of acetonitrile and phosphate buffer (pH 3.0) in the gradient ratio at a flow rate of 1 mL min(-1) with ultraviolet detection monitored at 232 nm. The parametric statistics, i.e., correlation coefficient of 0.999, was assessed for all the drugs having linearity over the tested concentration range (10-10,000 ng mL(-1)) in rat plasma using an unweighted calibration curve. The accuracy of samples for six replicate measurements at lower limit of quantitation level was within limit. The method was applicable for the quality control of the mentioned drugs in raw material, bulk drug and pharmaceutical formulations as well as in pharmacokinetic studies. PMID:25609600

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

    PubMed

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

    2016-09-01

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

  4. Near Infrared Spectroscopy for Burning Plasma Diagnostic Applications

    SciTech Connect

    Soukhanovskii, V A

    2008-06-18

    Ultraviolet and visible (UV-VIS, 200-750 nm) atomic spectroscopy of neutral and ion fuel species (H, D, T, Li) and impurities (e.g. He, Be, C, W) is a key element of plasma control and diagnosis on ITER and future magnetically confined burning plasma experiments (BPX). 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 address machine protection and plasma control diagnostic tasks, as well as 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 parasitic background emissions are expected to occur at very high plasma densities, low impurity densities, and at high plasma facing component temperatures.

  5. Rapid high-performance liquid chromatographic method for determination of adefovir in plasma using UV detection: application to pharmacokinetic studies.

    PubMed

    Foroutan, Seyed Mohsen; Zarghi, Afshin; Shafaati, Alireza; Movahed, Hooman; Khoddam, Arash

    2011-01-01

    A rapid, sensitive and reproducible HPLC method was developed and validated for the analysis of adefovir (CAS 106941-25-7) in human plasma. The separation was achieved on a monolithic silica column (Chromolith Performance RP-18e, 100 x 4.6 mm) using acetonitrile-ammonium dihydrogen phosphate buffer (6:94, v/v), pH 5.2, as the mobile phase at a flow rate of 1.5 ml min(-1). The wavelength was set at 260 nm. The assay enables the measurement of adefovir for therapeutic drug monitoring with a minimum quantification limit of 1 ng ml(-1). The method involves a simple protein precipitation procedure. Analytical recovery was complete. The calibration curve was linear over the concentration range 1-40 ng ml(-1). The coefficients of variation for inter-day and intra-day assay were found to be less than 5%. The method was applied to the determination of adefovir in plasma from 12 subjects dosed with adefovir 2 x 10 mg tablets and pharmacokinetic parameters were evaluated. PMID:21950152

  6. Simultaneous determination of roflumilast and its metabolite in human plasma by LC-MS/MS: Application for a pharmacokinetic study.

    PubMed

    Cui, Xinge; Huang, Jie; Zheng, Xin; Jiang, Ji; Kuang, Yun; Hu, Pei

    2016-09-01

    Roflumilast had shown good efficacy and safety in Caucasian COPD patients after oral administration of 0.5mg. The main active metabolite of it is roflumilast N-oxide. A reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) quantitation method was developed for the simultaneous determination of them in human plasma with rather low limits of quantitation for roflumilast (0.02ng/mL) and roflumilast N-oxide (0.04ng/mL). Human plasma samples were prepared by solid phase extraction (SPE), which ensured high recovery and slight matrix effect for the both analytes. This method showed good linearity, accuracy, precision and stability in the range of 0.02-10ng/mL and 0.04-50ng/mL for roflumilast and roflumilast N-oxide respectively. The developed method was successfully applied for the pharmacokinetic research in Chinese healthy volunteers after oral administration of 0.25mg, 0.375mg and 0.5mg of roflumilast tablet. PMID:27423044

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

    PubMed

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

    2006-01-01

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

  8. Systematic study of plasma flow during plasma sheet thinnings

    NASA Technical Reports Server (NTRS)

    Lui, A. T. Y.; Frank, L. A.; Ackerson, K. L.; Meng, C.-I.; Akasofu, S.-I.

    1977-01-01

    On the basis of a study of Imp 6 measurements of plasma flow, it is concluded that there is no clear indication of a predominance of tailward plasma flow beyond about X = -15 R sub E in the midnight sector of the plasma sheet during the expansive phase of a substorm. In fact, it is shown statistically that sunward plasma flow is more frequently observed in the midnight sector within about 30 R sub E from the earth than in any other direction during plasma sheet thinning at the substorm expansion. This result supports the conclusion that there is no definite evidence for the formation of a reconnection neutral line in the near-earth plasma sheet during most substorms.

  9. 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.

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

    PubMed

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

    2016-05-10

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

  11. Plasma discharge characteristics in compact SF6 radio-frequency plasma source for plasma etching application

    NASA Astrophysics Data System (ADS)

    Motomura, Taisei; Takahashi, Kazunori; Kasashima, Yuji; Uesugi, Fumihiko; Ando, Akira

    2015-09-01

    In order to create a compact plasma etching reactor, plasma discharge characteristics in compact SF6 radio-frequency (RF) plasma source which has a chamber diameter of 40 mm have been studied. Convergent magnetic field configuration produced by a solenoid coil and a permanent magnet located behind substrate is employed for efficient plasma transport downstream of plasma source. A discharge characteristics with the changes in relative emission intensity of fluorine atom of FI at 703.7 nm in compact SF6 plasma source are discussed: the dependence of relative emission intensity on the magnetic field strength, the RF input power, and the mass flow rate of the SF6 gas. The relative emission intensity was significantly increased when the RF input power is ~150 W. We present the fundamental etching performance (especially etching rate) of compact plasma source, and then the etching rate of 0.1-1.0 μm/min was obtained under the condition of a RF input power of 50-200 W, a mass flow rate of SF6 of 5.5 sccm and a bias RF power of 20 W. The results of test etching will be shown in presentation.

  12. 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.

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

    PubMed

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

    2014-08-15

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

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  16. 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.

  17. Developments and Plasma Studies at the ATOMKI-ECRIS

    SciTech Connect

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

    2005-03-15

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

  18. 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...

  19. 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. PMID:26773890

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

    NASA Astrophysics Data System (ADS)

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

    2006-10-01

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

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

    PubMed

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

    2011-12-01

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

  2. 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.

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

    NASA Astrophysics Data System (ADS)

    Isaka, Katsuo

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

  4. 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

  5. Characteristics and potential applications of an ORNL microwave ECR multicusp plasma ion source

    SciTech Connect

    Tsai, C.C.

    1990-01-01

    A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source that has two ECR plasma production regions and uses multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasma over large areas of 300 to 400 cm{sup 2} and could be scaled up to produce uniform plasma over 700 cm{sup 2} or larger. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The working gases used were argon, helium, hydrogen, and oxygen. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of the discharge parameters. The discharge characteristics and a hypothetical discharge mechanism for this plasma source are described and discussed. Potential applications, including plasma and ion-beam sources for manufacturing advanced microelectronics, for space electric propulsion, and for fusion research, are discussed. 10 refs., 10 figs.

  6. 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.

  7. 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. PMID:27168757

  8. 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

  9. Pulse-discharge plasmas for plasma-accelerator applications

    SciTech Connect

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

    2012-12-21

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

  10. 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.

  11. 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

  12. 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).

  13. 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.

  14. The application of platelet-rich plasma in the treatment of deep dermal burns: A randomized, double-blind, intra-patient controlled study.

    PubMed

    Marck, Roos E; Gardien, Kim L M; Stekelenburg, Carlijn M; Vehmeijer, Marielle; Baas, D; Tuinebreijer, Wim E; Breederveld, Roelf S; Middelkoop, Esther

    2016-07-01

    Platelet-rich plasma (PRP) is a fraction of blood with a platelet concentration above baseline. When platelets get activated, growth factors involved in wound healing are released. The application of PRP has shown good results in wound care, however, up to date no substantial research has been performed on the effect of PRP in burn treatment. This randomized double blind intra-patient controlled study investigates the effect of autologous PRP on wound healing in burns that require surgery with a meshed split skin graft (SSG). Fifty-two patients with various areas of deep dermal to full thickness burns, receiving surgery with a SSG were included after informed consent. Comparable study areas A and B (intra-patient) were appointed, randomized and either treated with a SSG and PRP or with a SSG alone. At day 5 to 7 postoperative, the epithelialization and graft take rate were assessed. Three, six, and twelve months postoperative, follow-up measurements were performed in the form of POSAS-questionnaires, DermoSpectroMeter, and Cutometer measurements. There was no statistically significant difference between the mean take rate nor the mean epithelialization rate at day 5-7 between the PRP-treated and control areas. However, PRP-treated wound areas showed more often better or equal epithelialization and take rates at day 5-7 than the standard treated areas. Minor effects were also seen in the reoperated and early operated subgroups. At 3, 6, and 12 months postoperative, POSAS scores from the patients and the observers, Dermaspectro-, and Cutometer measurements did not depict a significant difference between the PRP and standard treated areas. Concluding, the addition of PRP in the treatment of burn wounds did not result in improved graft take and epithelialization, nor could we demonstrate better scar quality. There was, however, a considerable variation in our clinical population. PMID:27169627

  15. Applicability of moire deflection tomography for diagnosing arc plasmas

    SciTech Connect

    Chen Yunyun; Song Yang; He Anzhi; Li Zhenhua

    2009-01-20

    The argon arc plasma whose central temperature, 1.90x10{sup 4} K, is used as a practical example for an experiment to research the applicability of moire deflection tomography in arc plasma flow-field diagnosis. The experimental result indicates that moire deflection of the measured argon arc plasma is very small, even smaller than that of a common flame with the maximal temperature of nearly 1.80x10{sup 3} K. The refractive-index gradient in moire deflection tomography mainly contributes to the temperature gradient in essence when the probe wavelength and pressure are certain in plasma diagnosis. The applicable temperature ranges of moire deflection tomography in the argon arc plasma diagnosis are given with the probe wavelength 532 nm at 1 atm in certain measuring error requirements. In a word, the applicable temperature range of moire deflection tomography for arc plasma diagnosis is intimately related to the probe wavelength and the practical measuring requirements.

  16. 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

  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. 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.

  19. 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. PMID:24795093

  20. Plasma traps for beam dynamics studies

    NASA Astrophysics Data System (ADS)

    Okamoto, Hiromi

    2004-05-01

    The collective motion of a space-charge-dominated beam in an accelerator has been investigated by many researchers for many years mainly through numerical simulations and analytic calculations. The recent interest in applying high-power ion beams to diverse purposes has made the understandings of various "space-charge effects" more and more important than ever. It is, however, extremely difficult to carry out the self-consistent theoretical study of such a multi-particle system exposed to complex external driving fields. In fact, we have always been forced to introduce some assumptions or simplifying models to draw approximate conclusions. Efforts have also been devoted to the experimental study of intense beams, but we encounter many practical difficulties again. As we can easily imagine, it is a tough job to observe and measure a particle beam traveling at great speed. Further, in a real accelerator, key experimental parameters, such as beam density, betatron tunes, magnet arrangements, etc., are not well controllable over a wide range. In order to overcome all these difficulties in conventional approaches, we proposed a novel experimental method utilizing a compact plasma trap system (instead of a huge, very expensive accelerator system) [1]. The basic idea is quite simple; namely, a charged-particle beam in an accelerator, if seen from the rest frame, is physically almost equivalent to a single-species plasma in a trap system. It is thus possible to employ a plasma trap for the systematic experimental study of space-charge-dominated beams. In this talk, a typical trap design is given and its applications to some beam-dynamics problems are discussed. [1] H. Okamoto and H. Tanaka, Nucl. Instr. Meth. A 437 (1999) 178; H. Okamoto, Y. Wada and R. Takai, Nucl. Instr. Meth. A 485 (2002) 244.

  1. 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.

  2. Potential applications of a new microwave ECR (electron cyclotron resonance) multicusp plasma ion source

    SciTech Connect

    Tsai, C.C.

    1990-01-01

    A new microwave electron cyclotron resonance (ECR) multicusp plasma ion source using two ECR plasma production regions and multicusp plasma confinement has been developed at Oak Ridge National Laboratory. This source has been operated to produce uniform and dense plasmas over large areas of 300 to 400 cm{sup 2}. The plasma source has been operated with continuous argon gas feed and pulsed microwave power. The discharge initiation phenomena and plasma properties have been investigated and studied as functions of discharge parameters. Together with the discharge characteristics observed, a hypothetical discharge mechanism for this plasma source is reported and discussed. Potential applications, including plasma and ion-beam processing for manufacturing advanced microelectronics and for space electric propulsion, are discussed. 7 refs., 6 figs.

  3. Study on the electromagnetic waves propagation characteristics in partially ionized plasma slabs

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Bin; Li, Bo-Wen; Nie, Qiu-Yue; Wang, Xiao-Gang; Kong, Fan-Rong

    2016-05-01

    Propagation characteristics of electromagnetic (EM) waves in partially ionized plasma slabs are studied in this paper. Such features are significant to applications in plasma antennas, blackout of re-entry flying vehicles, wave energy injection to plasmas, and etc. We in this paper developed a theoretical model of EM wave propagation perpendicular to a plasma slab with a one-dimensional density inhomogeneity along propagation direction to investigate essential characteristics of EM wave propagation in nonuniform plasmas. Particularly, the EM wave propagation in sub-wavelength plasma slabs, where the geometric optics approximation fails, is studied and in comparison with thicker slabs where the geometric optics approximation applies. The influences of both plasma and collisional frequencies, as well as the width of the plasma slab, on the EM wave propagation characteristics are discussed. The results can help the further understanding of propagation behaviours of EM waves in nonuniform plasma, and applications of the interactions between EM waves and plasmas.

  4. Validation of LC/MS electrospray ionisation method for the estimation of ursodiol in human plasma and its application in bioequivalence study.

    PubMed

    Sundd Singh, Sonu; Shah, Hiten; Gupta, Sapna; Jain, Manish; Sharma, Kuldeep; Patel, Harshvardhan; Shah, Bhavin; Thakkar, Purav; Patel, Nimesh; Shah, Ruchy; Bhushan Lohary, Braj

    2004-12-01

    A novel High Performance Liquid Chromatography-electrospray mass spectrometric method has been developed for the estimation of Ursodiol (Ursodeoxycholic acid)--a bile acid, in human plasma using Ornidazole as internal standard. The methodology involved solid phase extraction of the analyte from human plasma matrix. The chromatographic separation was achieved within seven minutes by an isocratic mobile phase containing 1.0 mM ammonium acetate and Acetonitrile (65:35, v/v), flowing through XTerra MS C18, 100 x 2.1, 3.5 microm analytical column, at a flow rate of 0.2 ml/min. Ion signals were measured in negative mode for Ursodiol and internal standard at m/z 391.3 and 278.1, respectively. A detailed validation of the method was performed as per USFDA guidelines and the standard curves were found to be linear in the range 50.0 ng/ml to 3000.0 ng/ml with the mean correlation coefficient more than 0.99. The absolute recovery was more than 54.90% for Ursodiol and 76.51% for internal standard. Ursodiol was stable for sixty-nine days at -70 degrees C and for eight hours at ambient temperature. After extraction from plasma, the reconstituted samples of Ursodiol were stable in autosampler at 10 degrees C for forty-eight hours. Upon subjecting to three freeze thaw cycles, there was no change in the recovery of the analyte. The integrity of the plasma samples remained unaffected even upon four-fold dilution with drug free human plasma. The method was simple, specific, sensitive, precise, accurate and suitable for bioequivalence and pharmacokinetic studies. It was successfully applied to the pilot bioequivalence study of Ursodiol in male human subjects. PMID:15689031

  5. Determination of the antifungal agent voriconazole in human plasma using a simple column-switching high-performance liquid chromatography and its application to a pharmacokinetic study.

    PubMed

    Nakagawa, Saori; Suzuki, Riho; Yamazaki, Reiko; Kusuhara, Yoko; Mitsumoto, Shoko; Kobayashi, Hikaru; Shimoeda, Sadahiko; Ohta, Shin; Yamato, Susumu

    2008-03-01

    A simple column-switching high performance liquid chromatographic (HPLC) method that does not require any complicated pretreatment has been developed to determine voriconazole in human plasma samples. An internal standard (IS) and borate buffer (pH 9.0) were added to plasma samples, which were then injected directly into the column-switching HPLC system using MAYI-ODS as a pre-column. The calibration curve for voriconazole showed good linearity in the range of 0.2-10 mug/ml in human plasma. The mean RSD (%) value of intra-day (n=6) and inter-day (n=5) precision were less than 5.4% and 8.2%, respectively. This system could make more than three hundred successive, accurate measurements when a washing step with ammonium acetate solution was added. This method was successfully applied to measure the therapeutic voriconazole level in patients' plasma, and was used in a study of voriconazole pharmacokinetics after oral administration. PMID:18310944

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

    PubMed

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

    2015-11-01

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

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

    PubMed

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

    2016-06-01

    An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the analysis of cefazolin and cefalothin in human plasma (total and unbound), urine and peritoneal dialysate has been developed and validated. Total plasma concentrations are measured following protein precipitation and are suitable for the concentration range of 1-500 µg/mL. Unbound concentrations are measured from ultra-filtered plasma acquired using Centrifree(®) devices and are suitable for the concentration range of 0.1-500 µg/mL for cefazolin and 1-500 µg/mL for cefalothin. The urine method is suitable for a concentration range of 0.1-20 mg/mL for cefazolin and 0.2-20 mg/mL for cefalothin. Peritoneal dialysate concentrations are measured using direct injection, and are suitable for the concentration range of 0.2-100 µg/mL for both cefazolin and cefalothin. The cefazolin and cefalothin plasma (total and unbound), urine and peritoneal dialysate results are reported for recovery, inter-assay precision and accuracy, and the lower limit of quantification, linearity, stability and matrix effects, with all results meeting acceptance criteria. The method was used successfully in a pilot pharmacokinetic study with patients with peritoneal dialysis-associated peritonitis, receiving either intraperitoneal cefazolin or cefalothin. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26394804

  8. 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. PMID:26812478

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    Semnani, Abbas; Macheret, Sergey; Peroulis, Dimitrios

    2015-09-01

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

  11. Development and validation of a highly sensitive LC-MS/MS method for the determination of acacetin in human plasma and its application to a protein binding study.

    PubMed

    Kim, Sang-Bum; Lee, Taehun; Lee, Hun Seok; Song, Chung Kil; Cho, Hyun-Jong; Kim, Dae-Duk; Maeng, Han-Joo; Yoon, In-Soo

    2016-02-01

    A highly sensitive bioanalytical method for the quantification of acacetin in human plasma was developed and comprehensively validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A minimal volume of human plasma sample (20 μL) was prepared by simple deproteinization with 80 μL of acetonitrile. Chromatographic separation was performed using Kinetex C18 column with an isocratic mobile phase consisting of water and acetonitrile (20:80, v/v) containing 0.1 % formic acid at a flow rate of 0.3 mL/min over a total run time of 2.0 min. Mass spectrometric detection was performed using multiple reaction-monitoring modes at the mass/charge transitions m/z 285.22 → 242.17 for acacetin and m/z 277.59 → 175.04 for chlorpropamide (internal standard). The calibration curve was linear over the range of 0.1-500 ng/mL with a lower limit of quantitation of 0.1 ng/mL. The coefficients of variation for both intra- and inter-day validation were less than 11.9 %, and the intra- and inter-day accuracy ranged from 96.8 to 108 %. Mean recovery of acacetin in human plasma was within the range of 91.5-95.6 %. This validated LC-MS/MS method was successfully applied to a human plasma protein binding study that indicated extensive and concentration-independent protein binding of acacetin in human plasma. PMID:26677081

  12. Simultaneous determination of rosuvastatin and fenofibric acid in human plasma by LC-MS/MS with electrospray ionization: assay development, validation and application to a clinical study.

    PubMed

    Trivedi, Ravi Kumar; Kallem, Raja Reddy; Mullangi, Ramesh; Srinivas, Nuggehally R

    2005-09-15

    values. RST and FFA were stable in the battery of stability studies, viz., bench-top, auto-sampler and freeze/thaw cycles. Stability of RST and FFA was established for 1 month at -80 degrees C. The application of the assay to a clinical study confirmed the utility of the assay. PMID:15970417

  13. Atmospheric-pressure plasma sources for biomedical applications

    NASA Astrophysics Data System (ADS)

    Park, G. Y.; Park, S. J.; Choi, M. Y.; Koo, I. G.; Byun, J. H.; Hong, J. W.; Sim, J. Y.; Collins, G. J.; Lee, J. K.

    2012-08-01

    Atmospheric-pressure plasmas (APPs) have attracted great interest and have been widely applied in biomedical applications, as due to their non-thermal and reactive properties, they interact with living tissues, cells and bacteria. Various types of plasma sources generated at atmospheric pressure have been developed to achieve better performance in specific applications. This article presents an overview of the general characteristics of APPs and a brief summary of their biomedical applications, and reviews a wide range of these sources developed for biomedical applications. The plasma sources are classified according to their power sources and cover a wide frequency spectrum from dc to microwaves. The configurations and characteristics of plasma sources are outlined and their biomedical applications are presented.

  14. 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.

  15. 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.

  16. Determination of a potential antitumor quassinoid in rat plasma by UPLC-MS/MS and its application in a pharmacokinetic study.

    PubMed

    Zhang, Qiang; Yuan, Yonghui; Cui, Jianchun; Xiao, Tingting; Deng, Zhipeng; Jiang, Daqing

    2016-05-30

    A sensitive UPLC-MS/MS method was developed and validated for the determination of brusatol in rat plasma. Chromatographic separation was carried out on a C18 column using methanol and 10mM ammonium acetate containing 0.1% (v/v) formic acid (55:45, v/v). The lower limit of quantification (LLOQ) was 1.0ng/mL for brusatol in plasma. The intra- and inter-day precision for the analyte ranged from 3.2% to 9.2% and 1.3% to 7.8%, and the accuracy was between 97.3% and 108.5%. The method was successfully applied in a pharmacokinetic study of brusatol following intravenous injection (0.5, 1.0, and 2.0mg/kg) of brusatol. PMID:26945636

  17. LC-MS/MS method for the determination of haemanthamine in rat plasma, bile and urine and its application to a pilot pharmacokinetic study.

    PubMed

    Hroch, Miloš; Mičuda, Stanislav; Havelek, Radim; Cermanová, Jolana; Cahlíková, Lucie; Hošťálková, Anna; Hulcová, Daniela; Řezáčová, Martina

    2016-07-01

    Evidence gathered in various studies points to the fact that haemanthamine, an isoquinoline alkaloid, has multiple medicinally interesting characteristics, including antitumor, antileukemic, antioxidant, antiviral, anticonvulsant and antimalarial activity. This work presents, for the first time, a universal LC-MS/MS method for analysis of haemanthamine in plasma, bile and urine which has been verified in a pilot pharmacokinetic experiment on rats. Chromatographic separation was performed on a pentafluorophenyl core-shell column in gradient elution mode with a mobile phase consisting of acetonitrile-methanol-ammonium formate buffer. A sample preparation based on liquid-liquid extraction with methyl tert-butyl ether was employed with ambelline used as an internal standard. Quantification was performed using LC-MS-ESI(+) in Selected Reaction Monitoring mode. The method was validated according to the European Medicines Agency guideline in a concentration range of 0.1-10 μmol/L in plasma, bile and urine. The concentration-time profiles of haemanthamine in plasma, bile and urine after a single i.v. bolus of 10 mg/kg have been described for the first time. The presented study addresses the lack of information on haemanthamine pharmacokinetics and also introduces a new universal method of haemanthamine analysis in complex biological matrices. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26577707

  18. 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. PMID:24771054

  19. 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. PMID:27284972

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

    PubMed Central

    2014-01-01

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

  1. 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.

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

    PubMed

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

    2006-09-14

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

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

    PubMed

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

    2016-08-15

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

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

    PubMed

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

    2016-09-01

    An efficient extraction of doxorubicin (Dox) from homemade stealth hyalurionic acid (HA)-based nanoparticles (NPs) in rat plasma could not be performed by previously published methods. Therefore, we attempted to establish the novel NPs-breaking and UPLC-MS-MS method for evaluating the pharmacokinetic profiles of the homemade stealth HA NPs in rats. The pretreatment method of plasma samples used the liquid-liquid extraction method with isopropyl alcohol as NPs-breaking and protein-precipitating solvents, and the NPs-breaking efficiency of isopropyl alcohol was as high as 97.2%. The analyte and gliclazide (internal standard) were extracted from plasma samples with isopropyl alcohol and were separated on UPLC BEH C18 with a mobile phase consisting of methanol and water (containing 0.1% formic acid). The method demonstrated good linearity at the concentrations ranging from 5 to 5,000 ng/mL. The intra- and interday relative standard deviations were >10%. Finally, the method was successfully applied to a pharmacokinetic study of homemade stealth HA-based NPs in rats following intravenous administration. PMID:27240566

  5. Determination of the novel antiarrhythmic drug sulcardine sulfate in human plasma by liquid chromatography tandem mass spectrometry and its application in a clinical pharmacokinetic study.

    PubMed

    Jia, Jingying; Liu, Gangyi; Zhang, Mengqi; Lu, Youli; Lu, Chuan; Liu, Yun; Zheng, Hongcao; Wang, Wei; Gui, Yuzhou; Yu, Chen; Li, Shuijun; Wang, Yiping

    2016-08-01

    Sulcardine sulfate (Sul), a novel antiarrhythmic agent, is currently in phase I and phase II clinical trials. To elucidate its clinical pharmacokinetic characteristics, a rapid and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the quantification of Sul in human plasma. Plasma samples were precipitated by acetonitrile and isotope-labeled sulcardine was added as internal standard. The analysis was carried out on a Capcell Pak C18 MG III column (100 × 2.0 mm, 5 μm) with 0.1% formic acid in acetonitrile solution and water (17:83, v/v) as mobile phase. The linear range was 5.0-1000 ng/mL for Sul, with a lower limit of quantification of 5.0 ng/mL. The intra- and inter-batch CVs were within ±11.0% and the accuracies were 4.9-107.3%. Our method, for the first time, allows the rapid (only 3.0 min) and accurate quantification of Sul in human plasma. The method has been successfully applied in the pharmacokinetic study of Sul in a clinical trial following oral administration of Sul to healthy volunteers. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26715470

  6. Rapid and simple method for determination of cephradine in human plasma using liquid chromatography-tandem mass spectrometry (LC-MS/MS): application to the bioequivalence study.

    PubMed

    Choi, Sang-Jun; Ryu, Ju-Hee; Lee, Heon-Woo; Lee, Myung-Jae; Seo, Ji-Hyung; Tak, Seong-Kun; Lee, Kyung-Tae

    2009-12-01

    A rapid and simple procedure was developed for the determination of cephradine in human plasma using liquid chromatography coupled with electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). After trichloroacetic acid (TCA) precipitation of proteins from plasma samples, cephradine and cefaclor (the internal standard; IS) were eluted on a CN column. The isocratic mobile phase used consisted of acetonitrile-water-formic acid (25:75:0.1, v/v/v). Cephradine and the IS were both detected in multiple reaction monitoring (MRM) mode at the transitions: m/z 350.0 --> 90.8 for cephradine and m/z 368.1 --> 106.0 for the IS, respectively. The calibration curve was linear over the concentration range from 0.05 to 50 microg/ml, and correlation coefficients were greater than 0.996. The coefficient of variation of assay precision was less than 9.36%, and its accuracy ranged from 87.92% to 111.16%. The chromatographic run time for each plasma sample was less than 3 min. The developed method was successfully applied to a bioequivalence study of cephradine in healthy male volunteers. PMID:19854118

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

    PubMed

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

    2014-02-01

    A simple, rapid, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated for the determination of cefadroxil, a first-generation cephalosporin, in rat plasma and urine. Rat samples were deproteinized with methanol, and then injected into the LC-MS/MS system (electro-spray ionization, positive mode) for quantification. Drugs were separated on a Synergi™ 4 μm Polar-RP 80A column (150 mm × 2.0 mm, 4 μm) with a mixture of 0.1% formic acid and methanol (62:38, v/v) as the mobile phase at 0.2 mL/min. Detection was performed using multiple reaction-monitoring modes at m/z 364.1→208.1 (for cefadroxil) and m/z 368.1→174.2 (for cefaclor, the internal standard). Method was specific and linear over the concentration range of 10-10,000 ng/mL. Validation parameters for cefadroxil, including accuracy, precision, absolute matrix effect, and stability in rat plasma and urine, were acceptable according to the biological method validation guidelines of the FDA (2001) [16]. Cefadroxil levels in plasma up to 1440 min or 480 min and urine up to 96 h were quantifiable following oral and intravenous cefadroxil administrations to rats at a dose of 2mg/kg, each, suggesting that the method is appropriate for routine pharmacokinetic studies including urinary recovery in rats. PMID:24412692

  8. 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. PMID:24327551

  9. 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. PMID:26129833

  10. Simultaneous determination of four secoiridoid and iridoid glycosides in rat plasma by ultra performance liquid chromatography-tandem mass spectrometry and its application to a comparative pharmacokinetic study.

    PubMed

    Wu, Yun; Ai, Yu; Wang, Fenrong; Ma, Wen; Bian, Qiaoxia; Lee, David Y-W; Dai, Ronghua

    2016-02-01

    A simple, reliable and rapid ultra-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of four secoiridoid (gentiopicroside, swertiamarin, sweroside) and iridoid glycosides (loganic acid), the bio-active ingredients in rat plasma. After liquid-liquid extraction, chromatographic separation was accomplished on a Shim-pack XR-ODS column with a mobile phase consisting of methanol and 0.1% formic acid in water. A triple quadrupole tandem mass spectrometry equipped with an electrospray ionization source was used as detector operating both in positive and negative ionization mode and operated by multiple-reaction monitoring scanning. The lower limits of quantitation were 0.25-30 ng/mL for all the analytes. Both intra-day and inter-day precision and accuracy of analytes were well within acceptance criteria (±15%). The mean extraction recoveries of analytes and internal standard (amygdalin) from rat plasma were all >71.4%. The validated method was successfully applied to a comparative pharmacokinetic study of four analytes in rat plasma between normal and arthritic rats after oral administration of Huo Luo Xiao Ling Dan and Gentiana macrophylla extract, respectively. Results showed significant differences in pharmacokinetic properties of the analytes among the different groups. PMID:26014753

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

    PubMed

    Lin, Jianyang; Yang, Tian; Zhang, Donghu

    2016-08-15

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

  12. Numerical modeling of arc plasma generator for chemical laser applications

    NASA Astrophysics Data System (ADS)

    Sagar, Vidya; Ravikant, Chhaya; Singhal, Gaurav; Mittal, Alok P.

    2012-05-01

    The results of the numerical modeling of arc discharge phenomenon relevant to hydrogen fluoride/deuterium fluoride (HF/DF) laser applications are given. The overall mechanics of arc discharge phenomena on the basis of numerical modeling employing the commercial code COMSOL is discussed. The equations for a 2D axisymmetric, weakly compressible, laminar flow with heat transfer and the coupled hydrodynamic and electromagnetic equations are solved using the SIMPLE algorithm. The variations in the material properties, temperature, and velocity due to the generated arc are studied. A comparison of the results obtained with those from the studies available in the literature validates the computational data. Since each designed plasma arc tunnel is unique in itself and specific in application, this would enable one to alter arc discharge parameters to optimize a specific laser.

  13. 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.

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

    PubMed

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

    2007-03-01

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

  15. An LC-MS/MS method for simultaneous determination of four flavonoids from Semen Oroxyli in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Zhang, Jing; Zhang, Sixi; Teng, Shiyong; Zhai, Lijie

    2016-05-01

    Semen Oroxyli, a Traditional Chinese Medicine, has many significant pharmacological activities such as analgesic, apoptotic, anti-inflammatory, anticancer, and immunostimulant activities. A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous quantitation of four flavonoids (oroxin A, oroxin B, baicalin, and chrysin) of Semen Oroxyli in rat plasma. After the addition of internal standard, plasma samples were pretreated with acetonitrile via a single-step protein precipitation. Chromatographic separation was performed on a Capcell Pak C18 column (100mm×2.0mm, 5μm particles) with isocratic elution using a mobile phase of methanol and 2mM ammonium acetate buffer solution (75:25, v/v) at a flow rate of 0.45mL/min. The analytes were detected without interference in the selection reaction monitoring mode with negative electrospray ionization. The validated method exhibited good linearity over a wide concentration range (r≥0.9958), and the lower limits of quantification were 1.0-5.5ng/mL for all the analytes. The mean extraction recoveries of the analytes from rat plasma exceeded 80.6%. The intra- and inter-day precisions at three QC levels were both less than 11.5%, and the accuracies ranged from -6.2% to 10.3%. The LC-MS/MS method was successfully applied to a pharmacokinetic study of the four flavonoids in rat plasma after oral administration of Semen Oroxyli extract. PMID:27038401

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    Topala, Ionut; Nastuta, Andrei

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

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

    PubMed Central

    Chen, Yuanyuan; Wu, Zhanhe

    2014-01-01

    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. PMID:26835332

  19. Environmental impact of plasma application to textiles

    NASA Astrophysics Data System (ADS)

    Radetic, M.; Jovancic, P.; Puac, N.; Petrovic, Z. Lj

    2007-05-01

    Plasma technology is currently implemented in a wide range of industrial processes due to high efficiency, low environmental impact and simplicity. Low-temperature plasma treatment can be an alternative to traditional wet processes in textile preparation and finishing, causing modification of the fibre surface, which is mainly responsible for the material end-use properties i.e. wettability, dyeability, printability, shrinking, pilling etc. Appropriate choice of gas and control of plasma operation conditions provide a variety of effects on textiles (improvement of dyeability, printability and colour fastness, improvement of adhesion properties of coated fabrics, increase in hydrophobicity and water resistance, etc.). However, in spite of extraordinary efficiency, multifunctionality and simplicity, low-temperature plasma treatments still cannot replace all wet finishing processes, though they can be viable pretreatments that offer plenty of environmental and economical benefits.

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

    NASA Astrophysics Data System (ADS)

    Woloszko, Jean; Gilbride, Charles

    2000-05-01

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

  1. Microwave imaging diagnostics for plasma fluctuation studies

    NASA Astrophysics Data System (ADS)

    Wang, Jian

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

  2. 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

  3. Dust Particle Growth and Application in Low Temperature Plasmas

    SciTech Connect

    Boufendi, L.

    2008-09-23

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

  4. Plasma Cleaning and Its Applications for Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Isabell, Thomas C.; Fischione, Paul E.; O'Keefe, Catherine; Guruz, Murat U.; Dravid, Vinayak P.

    1999-03-01

    The effectiveness of applying a high-frequency, low-energy, reactive gas plasma for the removal of hydrocarbon contamination from specimens and components for electron microscopy has been investigated with a variety of analytical techniques. Transmission electron microscopy (TEM) analysis of specimens that have been plasma cleaned shows an elimination of the carbonaceous contamination from the specimen. With extended cleaning times the removal of existing carbon contamination debris due to previously conducted microanalysis is shown. Following plasma cleaning, specimens may be examined in the electron microscope for several hours without exhibiting evidence of recontamination. The effectiveness of plasma cleaning is not limited to applications for TEM specimens. Scanning electron microscopy (SEM) specimens that have been plasma cleaned likewise show an elimination of carbonaceous contamination. Furthermore, other electron microscopy parts and accessories, such as aperture strips, specimen clamping rings, and Wehnelts, among others, can benefit from plasma cleaning.

  5. Pulsed plasma thruster contamination studies

    NASA Technical Reports Server (NTRS)

    Rudolph, L. K.; Jones, R. M.

    1979-01-01

    The exhaust plume of the one millipound pulsed plasma thruster has a measurable backflow upstream of the nozzle exit plane which may deposit on and degrade the performance of exposed spacecraft surfaces. High speed photographs and Faraday cup measurements suggest that this backflow is predominantly an electrically neutral, relatively low energy vapor. Articulated collimator quartz crystal microbalance measurements of this backflow were made for a thruster with a radically modified nozzle and a flat plate backflow shield, to determine the backflow sensitivity to nozzle design changes. The results are compared with the original nozzle backflow and show a measurable reduction in the backflow directly upstream of the shield.

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

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

    2015-01-01

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

  8. An LC-MS/MS method for determination of 3,6'-disinapoylsucrose in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Chen, Ying; Liu, Xin-Min; Pan, Rui-Le; Wang, Geng-Nan; Fu, Ying; Chang, Qi

    2009-12-01

    3,6'-Disinapoylsucrose (DSS), a major active component of traditional Chinese medicine Yuan-Zhi (the roots of Polygala tenuifolia), has significant effects for neuroprotection and improving learning memory. In order to explore the pharmacokinetic properties of DSS so as to further understand its in vivo activities, a sensitive LC-MS/MS method was developed for determination of DSS in rat plasma and applied to a pharmacokinetic study in the present study. After treatment by protein precipitation, the plasma sample was separated on a C(18) HPLC column and analyzed by a mass spectrometry under positive electrospray ionization. Multiple-reaction monitoring was employed to measure the ion transition at m/z 777.4 --> 409.2 for DSS and m/z 557.2 --> 309.1 for forsythin as internal standard. The method was linear over the studied concentration range of 0.5-1000.0 ng/mL. The precision and accuracy ranged from 1.4 to 18.4%, and from -3.7 to -9.5%, respectively, for within-day and between-day assay. Extraction recovery was higher than 86.6%. The limits of detection and quantification were 0.3 and 0.5 ng/mL, respectively. The present method was successfully applied to a pharmacokinetic study. DSS was found to have poor oral absorption with only about 0.5% bioavailability. PMID:19517426

  9. Plasma process optimization for N-type doping applications

    SciTech Connect

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

    2012-11-06

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

  10. Plasma characterization studies for materials processing

    SciTech Connect

    Pfender, E.; Heberlein, J.

    1995-12-31

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

  11. Radar Studies of Ionospheric Plasma Irregularities

    NASA Astrophysics Data System (ADS)

    Rao, P. B.

    2006-11-01

    High power high resolution VHF radars have proven to be powerful diagnostics to study ionospheric plasma irregularities, a space weather phenomenon of immense importance in view of its impact on space communication and navigation. The VHF radars at Jicamarca, Peru and Trivandrum, India have contributed greatly over the past four decades in arriving at the current understanding of the basic characteristics of the equatorial spread-F (ESF) and equatorial electrojet (EEJ) irregularities and the underlying plasma instability processes. Recent advances, involving high resolution radar observations of equatorial plasma irregularities, include the detection of supersonic plasma bubbles rising to heights beyond 1000 km, 150 km echoes and kilometric scale waves. The new and more recent developments in plasma irregularity studies came from the middle and upper atmosphere (MU) radar at Shigaraki, Japan and the mesosphere stratosphere troposphere (MST) radar at Gadanki, India. The new types of plasma irregularity structures observed by this mid- and low latitude VHF radars cover the well known quasi- periodic (QP) waves, tidal ion layers, kilometric scale waves and structures in the collision dominated lower E region. The paper presents an overview on the recent advances in the radar technique and the above mentioned new developments in observation and theory of the equatorial and low latitude ionospheric plasma irregularities.

  12. Hypervelocity Dust Injection for Plasma Diagnostic Applications

    NASA Astrophysics Data System (ADS)

    Ticos, Catalin

    2005-10-01

    Hypervelocity micron-size dust grain injection was proposed for high-temperature magnetized plasma diagnosis. Multiple dust grains are launched simultaneously into high temperature plasmas at several km/s or more. The hypervelocity dust grains are ablated by the electron and ion fluxes. Fast imaging of the resulting luminous plumes attached to each grain is expected to yield local magnetic field vectors. Combination of multiple local magnetic field vectors reproduces 2D or even 3D maps of the internal magnetic field topology. Key features of HDI are: (1) a high spatial resolution, due to a relatively small transverse size of the elongated tail, and (2) a small perturbation level, as the dust grains introduce negligible number of particles compared to the plasma particle inventory. The latter advantage, however, could be seriously compromised if the gas load from the accelerator has an unobstructed access to the diagnosed plasma. Construction of a HDI diagnostic for National Spherical Torus Experiment (NSTX), which includes a coaxial plasma gun for dust grain acceleration, is underway. Hydrogen and deuterium gas discharges inside accelerator are created by a ˜ 1 mF capacitor bank pre-charged up to 10 kV. The diagnostic apparatus also comprises a dust dispenser for pre-loading the accelerator with dust grains, and an imaging system that has a high spatial and temporal resolution.

  13. Plasma mass filtering techniques: applications and requirements

    NASA Astrophysics Data System (ADS)

    Gueroult, Renaud; Fisch, Nathaniel J.

    2013-10-01

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

  14. 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. PMID:21862421

  15. Simultaneous quantification of naproxcinod and its active metabolite naproxen in rat plasma using LC-MS/MS: application to a pharmacokinetic study.

    PubMed

    Shi, Xiaowei; Shang, Weiding; Wang, Shuang; Xue, Na; Hao, Yanxia; Wang, Yabo; Sun, Mengmeng; Du, Yumin; Cao, Deying; Zhang, Kai; Shi, Qingwen

    2015-01-26

    In this study, a liquid chromatography-tandem mass spectrometry method was developed and validated to simultaneously determine naproxcinod and naproxen concentrations in rat plasma for the first time. Plasma samples were prepared by simple one-step extraction with methanol for protein precipitation using only 50 μL plasma. Separation was performed on a Synergi Fusion-RP C18 column with a run time of 4 min. Naproxcinod, naproxen and internal standard concentrations were detected in the positive ion mode using multiple reaction monitoring (MRM) of the transitions at m/z 348.2→302.2, 231.1→185.1 and 271.2→203.1, respectively. The calibration curves were linear, with all correlation coefficients being ≥0.9952, in the range of 1.00-400 ng/mL for naproxcinod and 20.0-8000 ng/mL for naproxen. Their accuracy was in the range of -8.1% to 8.7%, and the intra- and inter-day variations were ≤4.53%. The mean extraction recovery of all analytes was more than 93.1% efficient. Stability testing showed that naproxcinod and naproxen remained stable during the whole analytical procedure. After validation, the method was successfully applied to a pharmacokinetic study of naproxcinod and naproxen in rats. The AUC0-∞ of naproxen was 74.6 times larger than that of naproxcinod, which indicated that naproxcinod was rapidly metabolized into naproxen in rats. PMID:25550191

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

    PubMed

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

    2016-06-01

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

  17. Measurement of sorafenib plasma concentration by high-performance liquid chromatography in patients with advanced hepatocellular carcinoma: is it useful the application in clinical practice? A pilot study.

    PubMed

    Fucile, Carmen; Marenco, Simona; Bazzica, Marco; Zuccoli, Maria Laura; Lantieri, Francesca; Robbiano, Luigi; Marini, Valeria; Di Gion, Paola; Pieri, Giulia; Stura, Paola; Martelli, Antonietta; Savarino, Vincenzo; Mattioli, Francesca; Picciotto, Antonino

    2015-01-01

    Pharmacokinetics and dose-finding studies on sorafenib were conducted on heterogeneous groups of patients with solid tumors. Portal hypertension, gut motility impairment and altered bile enterohepatic circulation may explain different sorafenib toxicological profile in cirrhotic patients. This study evaluated sorafenib plasma concentration in a homogeneous group of cirrhotic patients with hepatocellular carcinoma (HCC). Sorafenib concentrations were determined by liquid chromatography in 12 consecutive patients. Data have been evaluated by the generalized estimating equations method (p value statistical level was set at α = 0.05). (1) There were not significant differences between sorafenib concentrations in patients who tolerate the full dose versus patients with reduced dose due to toxicity; (2) the average sorafenib concentrations measured 3 h after the morning dosing were lower than those measured 12 h after the evening dosing (p = 0.005); (3) sorafenib concentrations decrease overtime (p < 10(-4)); (4) it has been found an association between the development of severe adverse reactions and sorafenib concentrations (p < 10(-5)). The relationship between dose and concentration of sorafenib in HCC patients is poor and not clinically predictable, confirming the variability both in the maximum tolerated dose and in plasma concentrations. Several factors may influence the pharmacokinetics in patients with liver disease. This may explain the inter-patient variability of concentrations and the lack of differences in concentration at different dosages. It could be interesting to extend the series of HCC patients to enhance information on the kinetics of the drug; furthermore, to establish a threshold of plasma sorafenib concentrations to predict severe adverse reactions would be clinically useful. PMID:25429830

  18. 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.

  19. 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.-

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

    PubMed

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

    2016-07-01

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

  1. Quantitative determination of periplocymarin in rat plasma and tissue by LC-MS/MS: application to pharmacokinetic and tissue distribution study.

    PubMed

    Yan, Kaijing; Wang, Xiangyang; Jia, Yumeng; Chu, Yang; Guan, Xiufeng; Ma, Xiaohui; Li, Wei; Pan, Guixiang; Zhou, Shuiping; Sun, He; Liu, Changxiao

    2016-08-01

    A simple, rapid and sensitive liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for the determination of periplocymarin in biological samples was developed and successfully applied to the pharmacokinetic and tissue distribution study of periplocymarin after oral administration of periplocin. Biological samples were processed with ethyl acetate by liquid-liquid extraction, and diazepam was used as the internal standard. Periplocymarin was analyzed on a C18 column with isocratic eluted mobile phase composed of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2 mL/min (73:27, v/v). Detection was performed on a triple-quadrupole tandem mass spectrometer using positive-ion mode electrospray ionization in the selected reaction monitoring mode. The MS/MS ion transitions monitored were m/z 535.3→355.1 and 285.1→193.0 for periplocymarin and diazepam, respectively. Good linearity was observed over the concentration ranges. The lower limit of quantification was 0.5 ng/mL in plasma and tested tissues. The intra-and inter-day precisions (relative standard deviation) were <10.2 and 10.5%, respectively, and accuracies (relative error) were between -6.8 and 8.9%. Recoveries in plasma and tissue were >90%. The validated method was successfully applied to the pharmacokinetic and tissue distribution studies of periplocymarin in rats. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26663385

  2. Development and validation of a UPLC-MS/MS method for quantitation of droxidopa in human plasma: Application to a pharmacokinetic study.

    PubMed

    Wang, Haidong; Yang, Guangsheng; Zhou, Jinyu; Pei, Jiang; Zhang, Qiangfeng; Song, Xingfa; Sun, Zengxian

    2016-08-01

    In this study, a simple and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for quantitation of droxidopa in human plasma for the first time. A simple plasma protein precipitation method using methanol containing 3% formic acid was selected, and the separation was achieved by an Acquity UPLC™ BEH Amide column (2.1mm×50mm, 1.7μm) with a gradient elution using acetonitrile, ammonium formate buffer and formic acid as mobile phase. The detection of droxidopa and benserazide (internal standard, IS) was performed using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring (MRM). The precursor-to-product ion transitions m/z 214.2→m/z 152.0 for droxidopa, and m/z 258.1→m/z 139.1 for IS were used for quantification. A lower limit of quantification of 5.00ng/mL was achieved and the linear curve range was 5.00-4000ng/mL using a weighted (1/x(2)) linear regression model. Intra-assay and inter-assay precision was less than 10.2%, and the accuracy ranged from 0.1% to 2.1%. Stability, recovery and matrix effects were within the acceptance criteria recommended by the regulatory bioanalytical guidelines. The method was successfully applied to a pharmacokinetic study of droxidopa in healthy Chinese volunteers. PMID:27311027

  3. A simple LC-ESI-MS/MS method for quantification of bacopaside I in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Yin, Ruo-Feng; Xiong, Kun; Wen, Si-Min; Song, Zhi-Min; Xu, Feng

    2016-08-01

    Bacopaside I is one of the main pseudojujubogenin glycosides isolated from Bacopa monniera. In the present study, a rapid and robust LC-ESI-MS/MS method was developed and validated to quantify bacopaside I in rat plasma. After plasma samples were deproteinized by methanol, the post-treatment samples were analyzed on a Zorbax Eclipse Plus C18 (2.1×50mm, 1.8μm) column using a mobile phase of acetonitrile and water (65:35, v/v). Detection was performed on a triple-quadrupole tandem mass spectrometer with selected reaction monitoring (SRM) mode via electrospray ionization source. This method covered a linearity range of 10-2000ng/mL with the lower limit of quantification of 10ng/mL. The intra- and inter-day precisions of analysis were less than 10.2%, and the accuracies were between -11.1% and 8.4% at the concentrations of 25, 150 and 1800ng/mL. The total run time was 6.0min. This method was successfully applied to the preclinical pharmacokinetic study of bacopaside I following intravenous or oral administration to rats. PMID:27270262

  4. A LC-MS/MS method for the determination of stachyose in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Zhou, Yang; Xu, De-Sheng; Liu, Li; Qiu, Fu-Rong; Chen, Jiong-Liang; Xu, Guang-Lin

    2016-05-10

    A sensitive, simple and rapid analytical method based on a liquid chromatography-tandem mass spetrometry (LC-MS/MS) has been established and validated for the determination of stachyose in rat plasma. Plasma samples were prepared by protein precipitation with acetonitrile. Separation of stachyose and nystose (internal standard, IS) was achieved using acetonitrile-water (55:45, v/v) as the mobile phase at a flow rate of 1ml/min for 6min on an Asahipak NH2P-50 4E column with an Asahipak NH2P-50G 4A guard column. Detection and quantification were conducted by LC-MS/MS method in the negative ion mode using multiple reaction monitoring (MRM) transitions at m/z [M-H](-) 665.4→383.1 for stachyose and 665.5→485.0 for IS, respectively. The method was linear over the concentration ranges of 100-30000ng/ml with a lower limit of quantification (LLOQ) of 100ng/ml. The intra- and inter- day precision were all within 8.7% and the accuracy ranged from 97.2-108.4% and 98.3-102.4%, respectively. Stability studies indicated that stachyose was stable under short-term, long-term and three freeze-thaw storage conditions. The method was successfully applied to a pharmacokinetic study involving pulmonary administration of micronized Rehmannia glutinosa oligosaccharides (RGOS) to rats. PMID:26859612

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

    PubMed

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

    2016-01-01

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

  6. Validated LC--MS/MS method for determination of YH-8, a novel PKnB inhibitor, in rat plasma and its application to pharmacokinetic study

    PubMed Central

    Zhai, Qianqian; Pang, Jing; Li, Guoqing; Li, Congran; Yang, Xinyi; Yu, Liyan; Wang, Yucheng; Li, Jian; You, Xuefu

    2015-01-01

    (E)-Methyl-4-aryl-4-oxabut-2-enoate (YH-8) is a novel PKnB protein kinase inhibitor with good anti-tuberculosis activity. To evaluate its pharmacokinetics in rats, a sensitive and selective high performance liquid chromatography–tandem mass spectrometric (LC--MS/MS) method has been developed and validated for the quantification of YH-8 in rat plasma for the first time. Samples were pre-treated using a liquid--liquid extraction with ethyl acetate and the chromatographic separation was performed on a C18 column by gradient elution with methanol--water as the mobile phase. YH-8 was detected using a tandem mass spectrometer in positive selected reaction monitoring (SRM) mode. Method validation revealed good linearity over the range of 1–500 ng/mL for YH-8 with a lower limit of quantification (LLOQ) of 1 ng/mL. Intra- and inter-day precision of YH-8 assay in rat plasma samples were 2.0%–6.8%, with accuracy of the method being 100.69%–106.18%. Stability test showed that when spiked into rat plasma, YH-8 was stable for 12 h at room temperature, for up to 15 days at −70 °C, and after three freeze-thaw cycles. Extracted samples were found to be stable over 12 h in an auto-sampler. The method was successfully applied to the pharmacokinetic study of YH-8 in rats after oral administration at 100 mg/kg and 200 mg/kg. PMID:26579477

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

    PubMed

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

    2014-01-01

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

  8. The development and validation of a method for quantifying olanzapine in human plasma by liquid chromatography tandem mass spectrometry and its application in a pharmacokinetic study.

    PubMed

    Cavalcanti Bedor, Noely Camila Tavares; Galindo Bedor, Danilo César; Miranda de Sousa, Carlos Eduardo; Nunes Bonifácio, Felipe; da Mota Castelo Branco, Daniel; Bastos Leal, Leila; Pereira de Santana, Davi

    2015-03-01

    1. A rapid method using liquid chromatography tandem mass spectrometry for the quantification of olanzapine (OLZ) in human plasma was developed and validated. Venlafaxine was used as the internal standard (IS), and the samples were extracted from 400-μL human plasma with methyl tert-butyl ether for liquid-liquid extraction. 2. Chromatography was performed using an ACE C18, 125 × 4.6-mm i.d., 5-μm column. The mobile phase consisted of water with 0.1% formic acid for solvent A and acetonitrile with 0.1% formic acid for solvent B (50 : 50 v/v) in isocratic mode. The flow rate was 1.2 mL/min. The retention times for OLZ and the IS were 0.78 and 1.04 min, respectively. Tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring was used to detect OLZ and the IS (m/z: 313.1 > 256.1 and 278.1 > 260.2, respectively). 3. No significant matrix effects were observed on OLZ and the IS retention times, and the mean recovery of OLZ was 90.08%. The assay was linear in the concentration range of 1-20 ng/mL (R(2) = 0.9976). The intra- and inter-day precision were < 11.60% and the accuracy was < 1.66%. 4. This validated method was successfully applied to a pharmacokinetic study in which 10-mg OLZ tablets were administered to healthy volunteers and their plasma OLZ levels were monitored over time. The tests showed that the OLZ test and reference drug (Zyprexa(®)) were bioequivalent, as 90% of the confidence intervals were within the 80-125% interval proposed by regulatory agencies. PMID:25491375

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

    PubMed

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

    2012-06-15

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

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

    PubMed

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

    2016-01-01

    A novel, sensitive and rapid ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method for simultaneous quantification of four furostanol glycosides in rat plasma was established and validated. Ginsenoside Rb1 was used as an internal standard. Plasma samples were pretreated by liquid-liquid extraction with n-butanol and chromatographed on a C18 column (2.1×50 mm i.d., 2.6 μm) using a gradient elution program consisting of acetonitrile and water (containing 0.03% formic acid and 0.1 mM lithium acetate) at a flow rate of 0.4 mL/min. Lithium adduct ions were employed to enhance the response of the analytes in electrospray positive ionization mode and multiple reaction monitoring transitions were performed for detection. All calibration curves exhibited good linearity (r>0.999) over the range of 10-20,000 ng/mL for protodioscin and 2-4000 ng/mL for protogracillin, pseudoprotodioscin and pseudoprotogracillin. The recoveries of the whole analytes were more than 80.3% and exhibited no severe matrix effect. Meanwhile, the intra- and inter-day precisions were all less than 10.7% and accuracies were within the range of -8.1-12.9%. The four saponins showed rapid excretion and relative high plasma concentrations when the validated method was applied to the PK study of Dioscorea nipponica extracts by intragastric administration at low, medium and high dose to rats. Moreover, the T(1/2) and AUC(0-t) of each compound turned out to behave in a dose-dependent pattern by comparing them at different dose levels. PMID:26433169