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Sample records for core particles induce

  1. Core/shell silicon/polyaniline particles via in-flight plasma-induced polymerization

    International Nuclear Information System (INIS)

    Yasar-Inceoglu, Ozgul; Mangolini, Lorenzo; Zhong, Lanlan

    2015-01-01

    Although silicon nanoparticles have potential applications in many relevant fields, there is often the need for post-processing steps to tune the property of the nanomaterial and to optimize it for targeted applications. In particular surface modification is generally necessary to both tune dispersibility of the particles in desired solvents to achieve optimal coating conditions, and to interface the particles with other materials to realize functional heterostructures. In this contribution we discuss the realization of core/shell silicon/polymer nanoparticles realized using a plasma-initiated in-flight polymerization process. Silicon particles are produced in a non-thermal plasma reactor using silane as a precursor. After synthesis they are aerodynamically injected into a second plasma reactor into which aniline vapor is introduced. The second plasma initiates the polymerization reactor leading to the formation of a 3–4 nm thick polymer shell surrounding the silicon core. The role of processing conditions on the properties of the polymeric shell is discussed. Preliminary results on the testing of this material as an anode for lithium ion batteries are presented. (paper)

  2. Core/shell silicon/polyaniline particles via in-flight plasma-induced polymerization

    Science.gov (United States)

    Yasar-Inceoglu, Ozgul; Zhong, Lanlan; Mangolini, Lorenzo

    2015-08-01

    Although silicon nanoparticles have potential applications in many relevant fields, there is often the need for post-processing steps to tune the property of the nanomaterial and to optimize it for targeted applications. In particular surface modification is generally necessary to both tune dispersibility of the particles in desired solvents to achieve optimal coating conditions, and to interface the particles with other materials to realize functional heterostructures. In this contribution we discuss the realization of core/shell silicon/polymer nanoparticles realized using a plasma-initiated in-flight polymerization process. Silicon particles are produced in a non-thermal plasma reactor using silane as a precursor. After synthesis they are aerodynamically injected into a second plasma reactor into which aniline vapor is introduced. The second plasma initiates the polymerization reactor leading to the formation of a 3-4 nm thick polymer shell surrounding the silicon core. The role of processing conditions on the properties of the polymeric shell is discussed. Preliminary results on the testing of this material as an anode for lithium ion batteries are presented.

  3. Induced self-energy on a static scalar charged particle in the spacetime of a global monopole with finite core

    International Nuclear Information System (INIS)

    Barbosa, D; De Freitas, U; De Mello, E R Bezerra

    2011-01-01

    We analyze the induced self-energy and self-force on a scalar point-like charged test particle placed at rest in the spacetime of a global monopole admitting a general spherically symmetric inner structure to it. In order to develop this analysis we calculate the three-dimensional Green's function associated with this physical system. We explicitly show that for points outside the monopole's core the scalar self-energy presents two distinct contributions. The first one is induced by the non-trivial topology of the global monopole considered as a point-like defect and the second is a correction induced by the non-vanishing inner structure attributed to it. For points inside the monopole, the self-energy also present a similar structure, where now the first contribution depends on the geometry of the spacetime inside. As illustrations of the general procedure adopted, two specific models, namely flower-pot and the ballpoint-pen, are considered for the region inside. For these two different situations, we were able to obtain exact expressions for the self-energies and self-forces in the regions outside and inside the global monopole.

  4. Induced self-energy on a static scalar charged particle in the spacetime of a global monopole with finite core

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, D; De Freitas, U; De Mello, E R Bezerra, E-mail: denis.barros@ifpb.edu.br, E-mail: umbelino@fisica.ufpb.br, E-mail: emello@fisica.ufpb.br [Instituto Federal de Educacao, Ciencia e Tecnologia da ParaIba, 58.800-970, Sousa, PB (Brazil)

    2011-03-21

    We analyze the induced self-energy and self-force on a scalar point-like charged test particle placed at rest in the spacetime of a global monopole admitting a general spherically symmetric inner structure to it. In order to develop this analysis we calculate the three-dimensional Green's function associated with this physical system. We explicitly show that for points outside the monopole's core the scalar self-energy presents two distinct contributions. The first one is induced by the non-trivial topology of the global monopole considered as a point-like defect and the second is a correction induced by the non-vanishing inner structure attributed to it. For points inside the monopole, the self-energy also present a similar structure, where now the first contribution depends on the geometry of the spacetime inside. As illustrations of the general procedure adopted, two specific models, namely flower-pot and the ballpoint-pen, are considered for the region inside. For these two different situations, we were able to obtain exact expressions for the self-energies and self-forces in the regions outside and inside the global monopole.

  5. Induced self-energy on a static scalar charged particle in the spacetime of a global monopole with finite core

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Denis; Freitas, Umbelino; Mello, Eugenio Bezerra de [Instituto Federal de Educacao, Ciencia e Tecnologia da Paraiba (IFPB), Joao Pessoa, PB (Brazil); Universidade Federal da Paraiba (IFPB), PB (Brazil)

    2011-07-01

    Full text: Global monopoles are heavy spherically symmetric topological objects which may have been formed by the vacuum phase transition in the early universe after Planck time. Although the global monopole was first introduced by Sokolov and Starobinsky, its gravitational effects have been analyzed by Barriola and Vilenkin. We analyze the induced self-energy and self-force on a scalar point-like charged test particle placed at rest in the spacetime of a global monopole admitting a general spherically symmetric inner structure to it. In order to develop this analysis we calculate the three-dimensional Green function associated with this physical system. We explicitly show that for points outside the monopoles core the scalar self-energy presents two distinct contributions. The first one is induced by the non-trivial topology of the global monopole considered as a point-like defect and the second is a correction induced by the non-vanishing inner structure attributed to it. For points inside the monopole, the self-energy also present a similar structure, where now the first contribution depends on the geometry of the spacetime inside. As illustrations of the general procedure adopted, two specific models, namely flower-pot and the ball-point pen, are considered for the region inside. For these two different situations, we were able to obtain exact expressions for the self-energies and self-forces in the regions outside and inside the global monopole. (author)

  6. Induced self-energy on a static scalar charged particle in the spacetime of a global monopole with finite core

    International Nuclear Information System (INIS)

    Barbosa, Denis; Freitas, Umbelino; Mello, Eugenio Bezerra de

    2011-01-01

    Full text: Global monopoles are heavy spherically symmetric topological objects which may have been formed by the vacuum phase transition in the early universe after Planck time. Although the global monopole was first introduced by Sokolov and Starobinsky, its gravitational effects have been analyzed by Barriola and Vilenkin. We analyze the induced self-energy and self-force on a scalar point-like charged test particle placed at rest in the spacetime of a global monopole admitting a general spherically symmetric inner structure to it. In order to develop this analysis we calculate the three-dimensional Green function associated with this physical system. We explicitly show that for points outside the monopoles core the scalar self-energy presents two distinct contributions. The first one is induced by the non-trivial topology of the global monopole considered as a point-like defect and the second is a correction induced by the non-vanishing inner structure attributed to it. For points inside the monopole, the self-energy also present a similar structure, where now the first contribution depends on the geometry of the spacetime inside. As illustrations of the general procedure adopted, two specific models, namely flower-pot and the ball-point pen, are considered for the region inside. For these two different situations, we were able to obtain exact expressions for the self-energies and self-forces in the regions outside and inside the global monopole. (author)

  7. An amino-terminal segment of hantavirus nucleocapsid protein presented on hepatitis B virus core particles induces a strong and highly cross-reactive antibody response in mice

    International Nuclear Information System (INIS)

    Geldmacher, Astrid; Skrastina, Dace; Petrovskis, Ivars; Borisova, Galina; Berriman, John A.; Roseman, Alan M.; Crowther, R. Anthony; Fischer, Jan; Musema, Shamil; Gelderblom, Hans R.; Lundkvist, Aake; Renhofa, Regina; Ose, Velta; Krueger, Detlev H.; Pumpens, Paul; Ulrich, Rainer

    2004-01-01

    Previously, we have demonstrated that hepatitis B virus (HBV) core particles tolerate the insertion of the amino-terminal 120 amino acids (aa) of the Puumala hantavirus nucleocapsid (N) protein. Here, we demonstrate that the insertion of 120 amino-terminal aa of N proteins from highly virulent Dobrava and Hantaan hantaviruses allows the formation of chimeric core particles. These particles expose the inserted foreign protein segments, at least in part, on their surface. Analysis by electron cryomicroscopy of chimeric particles harbouring the Puumala virus (PUUV) N segment revealed 90% T = 3 and 10% T = 4 shells. A map computed from T = 3 shells shows additional density splaying out from the tips of the spikes producing the effect of an extra shell of density at an outer radius compared with wild-type shells. The inserted Puumala virus N protein segment is flexibly linked to the core spikes and only partially icosahedrally ordered. Immunisation of mice of two different haplotypes (BALB/c and C57BL/6) with chimeric core particles induces a high-titered and highly cross-reactive N-specific antibody response in both mice strains

  8. Recombinant in vitro assembled hepatitis C virus core particles induce strong specific immunity enhanced by formulation with an oil-based adjuvant

    Directory of Open Access Journals (Sweden)

    NELSON ACOSTA-RIVERO

    2009-01-01

    Full Text Available In the present work, immunogenicity of recombinant in vitro assembled hepatitis C virus core particles, HCcAg.120-VLPs, either alone or in combination with different adjuvants was evaluated in BALB/c mice. HCcAg.120-VLPs induced high titers of anti-HCcAg.120 antibodies and virus-specific cellular immune responses. Particularly, HCcAg.120-VLPs induced specific delayed type hypersensitivity, and generated a predominant T helper 1 cytokine pro file in immunized mice. In addition, HCcAg.120-VLPs prime splenocytes proliferate in vitro against different HCcAg.120-specific peptides, depending on either the immunization route or the adjuvant used. Remarkably, immunization with HCcAg.120-VLPs/Montanide ISA888 formulation resulted in a significant control of vaccinia virus titer in mice after challenge with a recombinant vaccinia virus expressing HCV core protein, vvCore. Animals immunized with this formulation had a marked increase in the number of IFN-γ producing spleen cells, after stimulation with P815 cells infected with vvCore. These results suggest the use of recombinant HCV core particles as components of therapeutic or preventive vaccine candidates against HCV.

  9. Effective particle magnetic moment of multi-core particles

    International Nuclear Information System (INIS)

    Ahrentorp, Fredrik; Astalan, Andrea; Blomgren, Jakob; Jonasson, Christian; Wetterskog, Erik; Svedlindh, Peter; Lak, Aidin; Ludwig, Frank; IJzendoorn, Leo J. van; Westphal, Fritz; Grüttner, Cordula; Gehrke, Nicole; Gustafsson, Stefan; Olsson, Eva; Johansson, Christer

    2015-01-01

    In this study we investigate the magnetic behavior of magnetic multi-core particles and the differences in the magnetic properties of multi-core and single-core nanoparticles and correlate the results with the nanostructure of the different particles as determined from transmission electron microscopy (TEM). We also investigate how the effective particle magnetic moment is coupled to the individual moments of the single-domain nanocrystals by using different measurement techniques: DC magnetometry, AC susceptometry, dynamic light scattering and TEM. We have studied two magnetic multi-core particle systems – BNF Starch from Micromod with a median particle diameter of 100 nm and FeraSpin R from nanoPET with a median particle diameter of 70 nm – and one single-core particle system – SHP25 from Ocean NanoTech with a median particle core diameter of 25 nm

  10. Effective particle magnetic moment of multi-core particles

    Science.gov (United States)

    Ahrentorp, Fredrik; Astalan, Andrea; Blomgren, Jakob; Jonasson, Christian; Wetterskog, Erik; Svedlindh, Peter; Lak, Aidin; Ludwig, Frank; van IJzendoorn, Leo J.; Westphal, Fritz; Grüttner, Cordula; Gehrke, Nicole; Gustafsson, Stefan; Olsson, Eva; Johansson, Christer

    2015-04-01

    In this study we investigate the magnetic behavior of magnetic multi-core particles and the differences in the magnetic properties of multi-core and single-core nanoparticles and correlate the results with the nanostructure of the different particles as determined from transmission electron microscopy (TEM). We also investigate how the effective particle magnetic moment is coupled to the individual moments of the single-domain nanocrystals by using different measurement techniques: DC magnetometry, AC susceptometry, dynamic light scattering and TEM. We have studied two magnetic multi-core particle systems - BNF Starch from Micromod with a median particle diameter of 100 nm and FeraSpin R from nanoPET with a median particle diameter of 70 nm - and one single-core particle system - SHP25 from Ocean NanoTech with a median particle core diameter of 25 nm.

  11. Effective particle magnetic moment of multi-core particles

    Energy Technology Data Exchange (ETDEWEB)

    Ahrentorp, Fredrik; Astalan, Andrea; Blomgren, Jakob; Jonasson, Christian [Acreo Swedish ICT AB, Arvid Hedvalls backe 4, SE-411 33 Göteborg (Sweden); Wetterskog, Erik; Svedlindh, Peter [Department of Engineering Sciences, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Lak, Aidin; Ludwig, Frank [Institute of Electrical Measurement and Fundamental Electrical Engineering, TU Braunschweig, D‐38106 Braunschweig Germany (Germany); IJzendoorn, Leo J. van [Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Westphal, Fritz; Grüttner, Cordula [Micromod Partikeltechnologie GmbH, D ‐18119 Rostock (Germany); Gehrke, Nicole [nanoPET Pharma GmbH, D ‐10115 Berlin Germany (Germany); Gustafsson, Stefan; Olsson, Eva [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Johansson, Christer, E-mail: christer.johansson@acreo.se [Acreo Swedish ICT AB, Arvid Hedvalls backe 4, SE-411 33 Göteborg (Sweden)

    2015-04-15

    In this study we investigate the magnetic behavior of magnetic multi-core particles and the differences in the magnetic properties of multi-core and single-core nanoparticles and correlate the results with the nanostructure of the different particles as determined from transmission electron microscopy (TEM). We also investigate how the effective particle magnetic moment is coupled to the individual moments of the single-domain nanocrystals by using different measurement techniques: DC magnetometry, AC susceptometry, dynamic light scattering and TEM. We have studied two magnetic multi-core particle systems – BNF Starch from Micromod with a median particle diameter of 100 nm and FeraSpin R from nanoPET with a median particle diameter of 70 nm – and one single-core particle system – SHP25 from Ocean NanoTech with a median particle core diameter of 25 nm.

  12. Effective particle magnetic moment of multi-core particles

    NARCIS (Netherlands)

    Ahrentorp, F.; Astalan, A.; Blomgren, J.; Jonasson, C.; Wetterskog, E.; Svedlindh, P.; Lak, A.; Ludwig, F.; Van IJzendoorn, L.J.; Westphal, F.; Grüttner, C.; Gehrke, N.; Gustafsson, S.; Olsson, E.; Johansson, C.

    2015-01-01

    In this study we investigate the magnetic behavior of magnetic multi-core particles and the differences in the magnetic properties of multi-core and single-core nanoparticles and correlate the results with the nanostructure of the different particles as determined from transmission electron

  13. Particle-core multiplets in 89Y

    International Nuclear Information System (INIS)

    Batsch, T.; Kownacki, J.; Zelazny, Z.; Guttormsen, M.; Ramsoey, T.; Rekstad, J.

    1987-10-01

    The 89 Y nucleus has been formed in its excited states via the 87 Rb(α,2n) reaction at incident energies 24-34 MeV. The γ-ray decay of the states has been studied by measuring γ-γ-t coincidences, angular distributions and relative excitation functions. The experimental results from the present investigation are in general agreement with the former studies. However, some corrections in the level scheme have been introduced. Eight new levels with spins up to around 31/2 ℎ have been observed. The uppermost levels have been arranged into a rotational-like sequence, suggesting a nuclear shape change. Using our and previously known data we have tried to locate and calculate the members of the 1g 9/2 x core multiplet. The present results are compared with the semi-empirical shell model and the particle-core weak coupling description

  14. Variable solar control using thermotropic core/shell particles

    Energy Technology Data Exchange (ETDEWEB)

    Muehling, Olaf; Seeboth, Arno; Ruhmann, Ralf; Potechius, Elvira; Vetter, Renate [Fraunhofer Institute for Applied Polymer Research (IAP), Department of Chromogenic Polymers, Volmerstr. 7B, 12489 Berlin (Germany); Haeusler, Tobias [Brandenburg University of Technology (BTU Cottbus), Chair of Applied Physics/Thermophysics, Konrad-Zuse-Str. 1, 03046 Cottbus (Germany)

    2009-09-15

    Subject of our recent investigations is the utilization of a reversible thermotropic material for a self-regulating sun protection glazing that controls the solar energy input in order to avoid overheating. Based on the well-established UV curing technology for laminated glass a superior thermotropic material with tunable switching characteristics and of low material costs was developed. The polymer layer contains core/shell particles homogeneously dispersed in a UV-cured resin. The particle core in turn consists of an n-alkane mixture that is responsible for the temperature-induced clear/opaque switching. To obtain particles of well-defined size and with a narrow size distribution, the miniemulsion polymerization technique was used. The visible and solar optical properties (normal-normal, normal-hemispherical, and normal-diffuse transmittance) in the off (clear) and in the on state (opaque) were determined by UV/Vis/NIR spectroscopy. Samples containing particles of high median diameter (>800 nm) primarily scatter in the forward direction. However, with smaller particles (300-600 nm) a higher backscattering (reflection) efficiency was achieved. The largest difference in the normal-hemispherical transmittance could be found with a particle amount of 6% and a median scattering domain diameter of {proportional_to}380 nm. (author)

  15. Core-shell particle composition by liquid phase infrared spectroscopy

    International Nuclear Information System (INIS)

    Ribeiro, Luiz F.B.; Machado, Ricardo A.F.; Goncalves, Odinei H.; Bona, Evandro

    2011-01-01

    Polymeric particles with core-shell morphology can offer advantages over conventional particles improving properties like mechanical and chemical resistance. However, particle composition must be known due to its influence on the final properties. In this work liquid phase infrared spectroscopy was used to determine the overall composition of core-shell particles composed by polystyrene (core) and poly(methyl methacrylate) (shell). Results were in agreement with those obtained with H 1 Nuclear Magnetic Resonance data (Goncalves et al, 2008). (author)

  16. Synthesis of Cationic Core-Shell Latex Particles

    NARCIS (Netherlands)

    Dziomkina, N.; Hempenius, Mark A.; Vancso, Gyula J.

    2006-01-01

    Surfactant-free seeded (core-shell) polymerization of cationic polymer colloids is presented. Polystyrene core particles with sizes between 200 nm and 500 nm were synthesized. The number average diameter of the colloidal core particles increased with increasing monomer concentration. Cationic shells

  17. Synthesis and characterization of mesoporous silica core-shell particles

    Directory of Open Access Journals (Sweden)

    Milan Nikolić

    2010-06-01

    Full Text Available Core-shell particles were formed by deposition of primary silica particles synthesized from sodium silicate solution on functionalized silica core particles (having size of ~0.5 µm prepared by hydrolysis and condensation of tetraethylortosilicate. The obtained mesoporous shell has thickness of about 60 nm and consists of primary silica particles with average size of ~21 nm. Scanning electron microscopy and zeta potential measurements showed that continuous silica shell exists around functionalized core particles which was additionally proved by FTIR and TEM results.

  18. Core-shell particles at fluid interfaces

    NARCIS (Netherlands)

    Buchcic, C.

    2016-01-01

    There is a growing interest in the use of particles as stabilizers for foams and emulsions. Applying hard particles for stabilization of fluid interface is referred to as Pickering stabilization. By using hard particles instead of surfactants and polymers, fluid interfaces can be effectively

  19. Core/shell particles containing liquid cores : morphology prediction, synthesis and characterization

    NARCIS (Netherlands)

    Zyl, van A.J.P.; Sanderson, R.D.; Wet-Roos, de D.; Klumperman, B.

    2003-01-01

    The ability to synthesize core/shell particles with distinct geometries is becoming increasingly important due to their potential applications. In this study structured particles with liquid cores and polymeric shells were synthesized by an in situ miniemulsion polymerization reaction. The resulting

  20. Infrared light extinction by charged dielectric core-coat particles

    OpenAIRE

    Thiessen, Elena; Heinisch, Rafael L.; Bronold, Franz X.; Fehske, Holger

    2014-01-01

    We study the effect of surplus electrons on the infrared extinction of dielectric particles with a core-coat structure and propose to use it for an optical measurement of the particle charge in a dusty plasma. The particles consist of an inner core with negative and an outer coat with positive electron affinity. Both the core and the coat give rise to strong transverse optical phonon resonances, leading to anomalous light scattering in the infrared. Due to the radial profile of the electron a...

  1. Magnetic core-shell silica particles

    NARCIS (Netherlands)

    Claesson, E.M.

    2007-01-01

    This thesis deals with magnetic silica core-shell colloids and related functionalized silica structures. Synthesis routes have been developed and optimized. The physical properties of these colloids have been investigated, such as the magnetic dipole moment, dipolar structure formation and

  2. Ultrafast Dynamics of Metallo-Dielectric Core-Shell Particles

    NARCIS (Netherlands)

    Shan, X.

    2008-01-01

    Optical properties of metallic nano-structures have attracted a lot of attention in the past decades. In this thesis, we focus on nano-sized silica-core gold-shell particles, study the linear, nonlinear and acoustic vibrations of the particles. The linear optical properties in the visible range of

  3. Capillary micromechanics for core-shell particles

    NARCIS (Netherlands)

    Kong, T.; Wang, Liqiu; Wyss, H.M.; Shum, H.C.

    2014-01-01

    In this work, we have developed a facile, economical microfluidic approach as well as a simple model description to measure and predict the mechanical properties of composite core–shell microparticles made from materials with dramatically different elastic properties. By forcing the particles

  4. Binding of ethidium to the nucleosome core particle. 2. Internal and external binding modes

    International Nuclear Information System (INIS)

    McMurray, C.T.; Small, E.W.; van Holde, K.E.

    1991-01-01

    The authors have previously reported that the binding of ethidium bromide to the nucleosome core particle results in a stepwise dissociation of the structure which involves the initial release of one copy each of H2A and H2B. In this report, they have examined the absorbance and fluorescence properties of intercalated and outside bound forms of ethidium bromide. From these properties, they have measured the extent of external, electrostatic binding of the dye versus internal, intercalation binding to the core particle, free from contribution by linker DNA. They have established that dissociation is induced by the intercalation mode of binding to DNA within the core particle DNA, and not by binding to the histones or by nonintercalative binding to DNA. The covalent binding of [ 3 H]-8-azidoethidium to the core particle clearly shows that < 1.0 adduct is formed per histone octamer over a wide range of input ratios. Simultaneously, analyses of steady-state fluorescence enhancement and fluorescence lifetime data from bound ethidium complexes demonstrate extensive intercalation binding. Combined analyses from steady-state fluorescence intensity with equilibrium dialysis or fluorescence lifetime data revealed that dissociation began when ∼14 ethidium molecules are bound by intercalation to each core particle and < 1.0 nonintercalated ion pair was formed per core particle

  5. Core-shell particles as model compound for studying fouling

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Nielsen, Troels Bach; Andersen, Morten Boel Overgaard

    2008-01-01

    Synthetic colloidal particles with hard cores and soft, water-swollen shells were used to study cake formation during ultrafiltration. The total cake resistance was lowest for particles with thick shells, which indicates that interparticular forces between particles (steric hindrance...... and electrostatic repulsion) influenced cake formation. At low pressure the specific cake resistance could be predicted from the Kozeny-Carman equation. At higher pressures, the resistance increased due to cake compression. Both cake formation and compression were reversible. For particles with thick shells...

  6. Hysteresis effects in the cores of particle accelerator magnets

    CERN Document Server

    AUTHOR|(CDS)2086181; Schoerling, Daniel

    A study of the hysteresis effects in the cores of particle accelerator magnets has been performed in the framework of the work presented in this thesis. This study has been focused on normal conducting particle accelerator magnets whose cores are manufactured using ferromagnetic materials. The magnetic circuits have been modelled using the developed models: one model for the magnetic circuit and one for the magnetization of the material in the core. The parameters of the magnetic circuit model have been identified with the help of simulations which rely on the finite element method (Opera 3D), while the parameters of the magnetic hysteresis model have been identified through experimental measurements performed using a method developed in the framework of this work. The modelling results have been validated by means of experimental measurements performed on two magnets: one small size magnet which has been specifically designed and manufactured, and one magnet which is currently used in a particle accelerator ...

  7. On Maximal Hard-Core Thinnings of Stationary Particle Processes

    Science.gov (United States)

    Hirsch, Christian; Last, Günter

    2018-02-01

    The present paper studies existence and distributional uniqueness of subclasses of stationary hard-core particle systems arising as thinnings of stationary particle processes. These subclasses are defined by natural maximality criteria. We investigate two specific criteria, one related to the intensity of the hard-core particle process, the other one being a local optimality criterion on the level of realizations. In fact, the criteria are equivalent under suitable moment conditions. We show that stationary hard-core thinnings satisfying such criteria exist and are frequently distributionally unique. More precisely, distributional uniqueness holds in subcritical and barely supercritical regimes of continuum percolation. Additionally, based on the analysis of a specific example, we argue that fluctuations in grain sizes can play an important role for establishing distributional uniqueness at high intensities. Finally, we provide a family of algorithmically constructible approximations whose volume fractions are arbitrarily close to the maximum.

  8. Size-exclusion chromatography using core-shell particles.

    Science.gov (United States)

    Pirok, Bob W J; Breuer, Pascal; Hoppe, Serafine J M; Chitty, Mike; Welch, Emmet; Farkas, Tivadar; van der Wal, Sjoerd; Peters, Ron; Schoenmakers, Peter J

    2017-02-24

    Size-exclusion chromatography (SEC) is an indispensable technique for the separation of high-molecular-weight analytes and for determining molar-mass distributions. The potential application of SEC as second-dimension separation in comprehensive two-dimensional liquid chromatography demands very short analysis times. Liquid chromatography benefits from the advent of highly efficient core-shell packing materials, but because of the reduced total pore volume these materials have so far not been explored in SEC. The feasibility of using core-shell particles in SEC has been investigated and contemporary core-shell materials were compared with conventional packing materials for SEC. Columns packed with very small core-shell particles showed excellent resolution in specific molar-mass ranges, depending on the pore size. The analysis times were about an order of magnitude shorter than what could be achieved using conventional SEC columns. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Importance of core electrostatic properties on the electrophoresis of a soft particle

    Science.gov (United States)

    De, Simanta; Bhattacharyya, Somnath; Gopmandal, Partha P.

    2016-08-01

    The impact of the volumetric charged density of the dielectric rigid core on the electrophoresis of a soft particle is analyzed numerically. The volume charge density of the inner core of a soft particle can arise for a dendrimer structure or bacteriophage MS2. We consider the electrokinetic model based on the conservation principles, thus no conditions for Debye length or applied electric field is imposed. The fluid flow equations are coupled with the ion transport equations and the equation for the electric field. The occurrence of the induced nonuniform surface charge density on the outer surface of the inner core leads to a situation different from the existing analysis of a soft particle electrophoresis. The impact of this induced surface charge density together with the double-layer polarization and relaxation due to ion convection and electromigration is analyzed. The dielectric permittivity and the charge density of the core have a significant impact on the particle electrophoresis when the Debye length is in the order of the particle size. We find that by varying the ionic concentration of the electrolyte, the particle can exhibit reversal in its electrophoretic velocity. The role of the polymer layer softness parameter is addressed in the present analysis.

  10. Photonic crystals of core-shell colloidal particles

    NARCIS (Netherlands)

    Velikov, K.P.; Moroz, A.; Blaaderen, A. van

    2001-01-01

    We report on the fabrication and optical transmission studies of thin three-dimensional (3D) photonic crystals of high-dielectric ZnS-core and low-dielectric SiO2-shell colloidal particles. These samples were fabricated using a vertical controlled drying method. The spectral position and width of a

  11. The coupling one quasi-particle to a Bohr core

    International Nuclear Information System (INIS)

    Lewenkopf, C.H.

    1988-01-01

    Odd nuclei are studied coupling one quasi-particle to a Bohr's core, solved by Kumar Baranger's method. Calculations are performed for energies and transition rates for the following isotopes: 133 Xe, 183 W, 99 Tc and 101 Rh. Limitations of the model are discussed. (author) [pt

  12. Energy and particle core transport in tokamaks and stellarators compared

    Energy Technology Data Exchange (ETDEWEB)

    Beurskens, Marc; Angioni, Clemente; Beidler, Craig; Dinklage, Andreas; Fuchert, Golo; Hirsch, Matthias; Puetterich, Thomas; Wolf, Robert [Max-Planck-Institut fuer Plasmaphysik, Greifswald/Garching (Germany)

    2016-07-01

    The paper discusses expectations for core transport in the Wendelstein 7-X stellarator (W7-X) and presents a comparison to tokamaks. In tokamaks, the neoclassical trapped-particle-driven losses are small and turbulence dominates the energy and particle transport. At reactor relevant low collisionality, the heat transport is limited by ion temperature gradient limited turbulence, clamping the temperature gradient. The particle transport is set by an anomalous inward pinch, yielding peaked profiles. A strong edge pedestal adds to the good confinement properties. In traditional stellarators the 3D geometry cause increased trapped orbit losses. At reactor relevant low collisionality and high temperatures, these neoclassical losses would be well above the turbulent transport losses. The W7-X design minimizes neoclassical losses and turbulent transport can become dominant. Moreover, the separation of regions of bad curvature and that of trapped particle orbits in W7-X may have favourable implications on the turbulent electron heat transport. The neoclassical particle thermodiffusion is outward. Without core particle sources the density profile is flat or even hollow. The presence of a turbulence driven inward anomalous particle pinch in W7-X (like in tokamaks) is an open topic of research.

  13. Predictable Particle Engineering: Programming the Energy Level, Carrier Generation, and Conductivity of Core-Shell Particles.

    Science.gov (United States)

    Yuan, Conghui; Wu, Tong; Mao, Jie; Chen, Ting; Li, Yuntong; Li, Min; Xu, Yiting; Zeng, Birong; Luo, Weiang; Yu, Lingke; Zheng, Gaofeng; Dai, Lizong

    2018-06-20

    Core-shell structures are of particular interest in the development of advanced composite materials as they can efficiently bring different components together at nanoscale. The advantage of this structure greatly relies on the crucial design of both core and shell, thus achieving an intercomponent synergistic effect. In this report, we show that decorating semiconductor nanocrystals with a boronate polymer shell can easily achieve programmable core-shell interactions. Taking ZnO and anatase TiO 2 nanocrystals as inner core examples, the effective core-shell interactions can narrow the band gap of semiconductor nanocrystals, change the HOMO and LUMO levels of boronate polymer shell, and significantly improve the carrier density of core-shell particles. The hole mobility of core-shell particles can be improved by almost 9 orders of magnitude in comparison with net boronate polymer, while the conductivity of core-shell particles is at most 30-fold of nanocrystals. The particle engineering strategy is based on two driving forces: catechol-surface binding and B-N dative bonding and having a high ability to control and predict the shell thickness. Also, this approach is applicable to various inorganic nanoparticles with different components, sizes, and shapes.

  14. Preparation of porous carbon particle with shell/core structure

    Directory of Open Access Journals (Sweden)

    2007-05-01

    Full Text Available Porous carbon particles with a shell/core structure have been prepared successfully by controlled precipitation of the polymer from droplets of oil-in-water emulsion, followed by curing and carbonization. The droplets of the oil phase are composed of phenolic resin (PFR, a good solvent (ethyl acetate and porogen (Poly(methyl methacrylate, PMMA. The microstructure was characterized in detail by scanning electron microscopy (SEM, transmission electron microscopy (TEM, nitrogen adsorption, and thermo gravimetric analysis (TGA. The obtained carbon particles have a capsular structure with a microporous carbon shell and a mesoporous carbon core. The BET surface area and porous volume are calculated to be 499 m2g-1 and 0.56 cm3g-1, respectively. The effects of the amount of porogen (PMMA, co-solvent (acetone and surfactant on the resultant structure were studied in detail.

  15. Hollow-core photonic band gap fibers for particle acceleration

    Directory of Open Access Journals (Sweden)

    Robert J. Noble

    2011-12-01

    Full Text Available Photonic band gap (PBG dielectric fibers with hollow cores are being studied both theoretically and experimentally for use as laser driven accelerator structures. The hollow core functions as both a longitudinal waveguide for the transverse-magnetic (TM accelerating fields and a channel for the charged particles. The dielectric surrounding the core is permeated by a periodic array of smaller holes to confine the mode, forming a photonic crystal fiber in which modes exist in frequency passbands, separated by band gaps. The hollow core acts as a defect which breaks the crystal symmetry, and so-called defect, or trapped modes having frequencies in the band gap will only propagate near the defect. We describe the design of 2D hollow-core PBG fibers to support TM defect modes with high longitudinal fields and high characteristic impedance. Using as-built dimensions of industrially made fibers, we perform a simulation analysis of prototype PBG fibers with dimensions appropriate for speed-of-light TM modes.

  16. Highly temperature responsive core-shell magnetic particles: synthesis, characterization and colloidal properties.

    Science.gov (United States)

    Rahman, Md Mahbubor; Chehimi, Mohamed M; Fessi, Hatem; Elaissari, Abdelhamid

    2011-08-15

    Temperature responsive magnetic polymer submicron particles were prepared by two step seed emulsion polymerization process. First, magnetic seed polymer particles were obtained by emulsion polymerization of styrene using potassium persulfate (KPS) as an initiator and divinylbenzne (DVB) as a cross-linker in the presence of oil-in-water magnetic emulsion (organic ferrofluid droplets). Thereafter, DVB cross-linked magnetic polymer particles were used as seed in the precipitation polymerization of N-isopropylacrylamide (NIPAM) to induce thermosensitive PNIPAM shell onto the hydrophobic polymer surface of the cross-linked magnetic polymer particles. To impart cationic functional groups in the thermosensitive PNIPAM backbone, the functional monomer aminoethylmethacrylate hydrochloride (AEMH) was used to polymerize with NIPAM while N,N'-methylenebisacrylamide (MBA) and 2, 2'-azobis (2-methylpropionamidine) dihydrochloride (V-50) were used as a cross-linker and as an initiator respectively. The effect of seed to monomer (w/w) ratio along with seed nature on the final particle morphology was investigated. Dynamic light scattering (DLS) results demonstrated particles swelling at below volume phase transition temperature (VPTT) and deswelling above the VPTT. The perfect core (magnetic) shell (polymer) structure of the particles prepared was confirmed by Transmission Electron Microscopy (TEM). The chemical composition of the particles were determined by thermogravimetric analysis (TGA). The effect of temperature, pH, ionic strength on the colloidal properties such as size and zeta potential of the micron sized thermo-sensitive magnetic particles were also studied. In addition, a short mechanistic discussion on the formation of core-shell morphology of magnetic polymer particles has also been discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Particle-induced thermonuclear fusion

    International Nuclear Information System (INIS)

    Salisbury, W.W.

    1980-01-01

    A nuclear fusion process for igniting a nuclear fusion pellet in a manner similar to that proposed for laser beams uses, an array of pulsed high energy combined particle beams, focused to bombard the pellet for isentropically compressing it to a Fermi-degenerate state by thermal blow-off and balanced beam momentum transfer. (author)

  18. Flow induced crystallisation of penetrable particles

    Science.gov (United States)

    Scacchi, Alberto; Brader, Joseph M.

    2018-03-01

    For a system of Brownian particles interacting via a soft exponential potential we investigate the interaction between equilibrium crystallisation and spatially varying shear flow. For thermodynamic state points within the liquid part of the phase diagram, but close to the crystallisation phase boundary, we observe that imposing a Poiseuille flow can induce nonequilibrium crystalline ordering in regions of low shear gradient. The physical mechanism responsible for this phenomenon is shear-induced particle migration, which causes particles to drift preferentially towards the center of the flow channel, thus increasing the local density in the channel center. The method employed is classical dynamical density functional theory.

  19. Synthesis of eccentric titania-silica core-shell and composite particles

    NARCIS (Netherlands)

    Demirors, A.F.; van Blaaderen, A.; Imhof, A.

    2009-01-01

    We describe a novel method to synthesize colloidal particles with an eccentric core-shell structure. Titania-silica core-shell particles were synthesized by silica coating of porous titania particles under Sto¨ber (Sto¨ber et al. J. Colloid Interface Sci. 1968, 26, 62) conditions. We can control

  20. Morphology and film formation of poly(butyl methacrylate)-polypyrrole core-shell latex particles

    NARCIS (Netherlands)

    Huijs, F; Lang, J

    Core-shell latex particles made of a poly(butyl methacrylate) (PBMA) core and a thin polypyrrole (PPy) shell were synthesized by two-stage polymerization. In the first stage, PBMA latex particles were synthesized in a semicontinuous process by free-radical polymerization. PBMA latex particles were

  1. Development of magnetic luminescent core/shell nanocomplex particles with fluorescence using Rhodamine 6G

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hee Uk; Song, Yoon Seok [Department of Chemical and Biological Engineering, Korea University, 5 Ga, Anam-Dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of); Park, Chulhwan [Department of Chemical Engineering, Kwangwoon University, 447-1 Wolgye-Dong, Nowon-Gu, Seoul 139-701 (Korea, Republic of); Kim, Seung Wook, E-mail: kimsw@korea.ac.kr [Department of Chemical and Biological Engineering, Korea University, 5 Ga, Anam-Dong, Sungbuk-Gu, Seoul 136-701 (Korea, Republic of)

    2012-12-15

    Graphical abstract: Display Omitted Highlights: ► A simple method was developed to synthesize Co-B/SiO{sub 2}/dye/SiO{sub 2} composite particles. ► The magnetic particle shows that highly luminescent and core/shell particles are formed. ► Such core/shell particles can be easily suspended in water. ► The magnetic particles could detect fluorescence for the application of biosensor. -- Abstract: A simple and reproducible method was developed to synthesize a novel class of Co-B/SiO{sub 2}/dye/SiO{sub 2} composite core/shell particles. Using a single cobalt core, Rhodamine 6G of organic dye molecules was entrapped in a silica shell, resulting in core/shell particles of ∼200 nm diameter. Analyses using a variety of techniques such as transmission electron microscopy, X-ray photoelectron spectroscopy, vibration sample magnetometry, confocal laser scanning microscopy, and fluorescence intensity demonstrated that dye molecules were trapped inside the core/shell particles. A photoluminescence investigation showed that highly luminescent and photostable core/shell particles were formed. Such core/shell particles can be easily suspended in water. The synthesized magnetic particles could be used to detect fluorescence on glass substrate arrays for bioassay and biosensor applications.

  2. DESIGN AND CONTROL OF SOAP-FREE HYDROPHILIC-HYDROPHOBIC CORE-SHELL LATEX PARTICLES WITH HIGH CARBOXYL CONTENT IN THE CORE OF THE PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Wen-jiao Ji; Yi-ming Jiang; Bo-tian Li; Wei Deng; Cheng-you Kan

    2012-01-01

    Soap-free hydrophilic-hydrophobic core-shell latex particles with high carboxyl content in the core of the particles were synthesized via the seeded emulsion polymerization using methyl methacrylate (MMA),butyl acrylate (BA),methacrylic acid (MAA),styrene (St) and ethylene glycol dimethacrylate (EGDMA) as monomers,and the influences of MMA content used in the core preparation on polymerization,particle size and morphology were investigated by transmission electron microscopy,dynamic light scattering and conductometric titration.The results showed that the seeded emulsion polymerization could be carried out smoothly using "starved monomer feeding process" when MAA content in the core preparation was equal to or less than 24 wt%,and the encapsulating efficiency of the hydrophilic P(MMA-BA-MAA-EGDMA) core with the hydrophobic PSt shell decreased with the increase in MAA content.When an interlayer of P(MMA-MAA-St) with moderate polarity was inserted between the P(MMA-BA-MAA-EGDMA) core and the PSt shell,well designed soap-free hydrophilic-hydrophobic core-shell latex particles with 24 wt% MAA content in the core preparation were obtained.

  3. Particle induced X-ray emission

    International Nuclear Information System (INIS)

    Cohen, D.D.

    1991-08-01

    The accelerator based ion beam technique of Particle Induced X-ray Emission (PIXE) is discussed in some detail. This report pulls together all major reviews and references over the last ten years and reports on PIXE in vacuum and using external beams. The advantages, limitations, costs and types of studies that may be undertaken using an accelerator based ion beam technique such as PIXE, are also discussed. 25 refs., 7 tabs., 40 figs

  4. Characterization of spherical core–shell particles by static light scattering. Estimation of the core- and particle-size distributions

    International Nuclear Information System (INIS)

    Clementi, Luis A.; Vega, Jorge R.; Gugliotta, Luis M.; Quirantes, Arturo

    2012-01-01

    A numerical method is proposed for the characterization of core–shell spherical particles from static light scattering (SLS) measurements. The method is able to estimate the core size distribution (CSD) and the particle size distribution (PSD), through the following two-step procedure: (i) the estimation of the bivariate core–particle size distribution (C–PSD), by solving a linear ill-conditioned inverse problem through a generalized Tikhonov regularization strategy, and (ii) the calculation of the CSD and the PSD from the estimated C–PSD. First, the method was evaluated on the basis of several simulated examples, with polystyrene–poly(methyl methacrylate) core–shell particles of different CSDs and PSDs. Then, two samples of hematite–Yttrium basic carbonate core–shell particles were successfully characterized. In all analyzed examples, acceptable estimates of the PSD and the average diameter of the CSD were obtained. Based on the single-scattering Mie theory, the proposed method is an effective tool for characterizing core–shell colloidal particles larger than their Rayleigh limits without requiring any a-priori assumption on the shapes of the size distributions. Under such conditions, the PSDs can always be adequately estimated, while acceptable CSD estimates are obtained when the core/shell particles exhibit either a high optical contrast, or a moderate optical contrast but with a high ‘average core diameter’/‘average particle diameter’ ratio. -- Highlights: ► Particles with core–shell morphology are characterized by static light scattering. ► Core size distribution and particle size distribution are successfully estimated. ► Simulated and experimental examples are used to validate the numerical method. ► The positive effect of a large core/shell optical contrast is investigated. ► No a-priori assumption on the shapes of the size distributions is required.

  5. Influence of Shell Thickness on the Colloidal Stability of Magnetic Core-Shell Particle Suspensions.

    Science.gov (United States)

    Neville, Frances; Moreno-Atanasio, Roberto

    2018-01-01

    We present a Discrete Element study of the behavior of magnetic core-shell particles in which the properties of the core and the shell are explicitly defined. Particle cores were considered to be made of pure iron and thus possessed ferromagnetic properties, while particle shells were considered to be made of silica. Core sizes ranged between 0.5 and 4.0 μm with the actual particle size of the core-shell particles in the range between 0.6 and 21 μm. The magnetic cores were considered to have a magnetization of one tenth of the saturation magnetization of iron. This study aimed to understand how the thickness of the shell hinders the formation of particle chains. Chain formation was studied with different shell thicknesses and particle sizes in the presence and absence of an electrical double layer force in order to investigate the effect of surface charge density on the magnetic core-shell particle interactions. For core sizes of 0.5 and 4.0 μm the relative shell thicknesses needed to hinder the aggregation process were approximately 0.4 and 0.6 respectively, indicating that larger core sizes are detrimental to be used in applications in which no flocculation is needed. In addition, the presence of an electrical double layer, for values of surface charge density of less than 20 mC/m 2 , could stop the contact between particles without hindering their vertical alignment. Only when the shell thickness was considerably larger, was the electrical double layer able to contribute to the full disruption of the magnetic flocculation process.

  6. Rotationally induced fragmentation in the prestellar core L1544

    Energy Technology Data Exchange (ETDEWEB)

    Klapp, Jaime; Zavala, Miguel [Departamento de Física, Instituto Nacional de Investigaciones Nucleares (ININ), Km. 36.5, Carretera México-Toluca, La Marquesa 52750, Estado de México (Mexico); Sigalotti, Leonardo Di G.; Peña-Polo, Franklin; Troconis, Jorge [Centro de Física, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado Postal 20632, Caracas 1020A (Venezuela, Bolivarian Republic of)

    2014-01-10

    Recent observations indicate that there is no correlation between the level of turbulence and fragmentation in detected protostellar cores, suggesting that turbulence works mainly before gravitationally bound prestellar cores form and that their inner parts are likely to be velocity coherent. Based on this evidence, we simulate the collapse and fragmentation of an isolated, initially centrally condensed, uniformly rotating core of total mass M = 5.4 M {sub ☉}, using the smoothed particle hydrodynamics code GADGET-2 modified with the inclusion of sink particles, in order to compare the statistical properties of the resulting stellar ensembles with previous gravoturbulent fragmentation models. The initial conditions are intended to fit the observed properties of the prestellar core L1544. We find that for ratios of the rotational to the gravitational energy β ≥ 0.05, a massive disk is formed at the core center from which a central primary condenses after ∼50 kyr. Soon thereafter the disk fragments into secondary protostars, consistent with an intermediate mode of star formation in which groups of 10-100 stars form from a single core. The models predict peak accretion rates between ∼10{sup –5} and 10{sup –4} M {sub ☉} yr{sup –1} for all stars and reproduce many of the statistical properties predicted from gravoturbulent fragmentation, suggesting that on the small scales of low-mass, dense cores these are independent of whether the contracting gas is turbulent or purely rotating.

  7. One-step synthesis of gold-polyaniline core-shell particles

    International Nuclear Information System (INIS)

    Wang Zhijuan; Yuan Junhua; Han Dongxue; Niu Li; Ivaska, Ari

    2007-01-01

    A one-step method has been developed for synthesizing gold-polyaniline (Au-PANI) core-shell particles by using chlorauric acid (HAuCl 4 ) to oxidize aniline in the presence of acetic acid and Tween 40 at room temperature. SEM images indicated that the resulting core-shell particles were composed of submicrometre-scale Au particles and PANI shells with an average thickness of 25 nm. Furthermore, a possible mechanism concerning the growth of Au-PANI particles was also proposed based on the results of control experiments

  8. Fused-core particle technology in high-performance liquid chromatography: An overview

    Directory of Open Access Journals (Sweden)

    Joseph J. Kirkland

    2013-10-01

    Full Text Available The advent of superficially porous particles (SPPs for packed HPLC columns has changed the way that many practitioners have approached the problem of developing needed separations. The very high efficiency of such columns, combined with convenient operating conditions, modest back pressures and the ability to use conventional HPLC instruments has resulted in intense basic studies of SPP technology, and widespread applications in many sciences. This report contains an overview of the SPP technology first developed in 2006 by Advanced Materials Technology, Inc., for sub-3-μm particles, then expanded into a family of SPP products with different particle sizes, pore sizes and other physical parameters. This approach was designed so that each particle of the family could be optimized for separating a particular group of compounds, usually based on solute size. Keywords: Superficially porous particles, Fused-core particles, Core–shell particles, Peptides, Proteins, Drug separations

  9. Synthesis of highly monodisperse particles composed of a magnetic core and fluorescent shell.

    Science.gov (United States)

    Nagao, Daisuke; Yokoyama, Mikio; Yamauchi, Noriko; Matsumoto, Hideki; Kobayashi, Yoshio; Konno, Mikio

    2008-09-02

    Highly monodisperse particles composed of a magnetic silica core and fluorescent polymer shell were synthesized with a combined technique of heterocoagulation and soap-free emulsion polymerization. Prior to heterocoagulation, monodisperse, submicrometer-sized silica particles were prepared with the Stober method, and magnetic nanoparticles were prepared with a modified Massart method in which a cationic silane coupling agent of N-trimethoxysilylpropyl- N, N, N-trimethylammonium chloride was added just after coprecipitation of Fe (2+) and Fe (3+). The silica particles with negative surface potential were heterocoagulated with the magnetic nanoparticles with positive surface potential. The magnetic silica particles obtained with the heterocoagulation were treated with sodium silicate to modify their surfaces with silica. In the formation of a fluorescent polymer shell onto the silica-coated magnetic silica cores, an amphoteric initiator of 2,2'-azobis[ N-(2-carboxyethyl)-2-2-methylpropionamidine] (VA-057) was used to control the colloidal stability of the magnetic cores during the polymer coating. The polymerization of St in the presence of a hydrophobic fluorophore of pyrene could coat the cores with fluorescent polymer shells, resulting in monodisperse particles with a magnetic silica core and fluorescent polymer shell. Measurements of zeta potential for the composite particles in different pH values indicated that the composite particles had an amphoteric property originating from VA-057 initiator.

  10. [The true story and advantages of the famous Hepatitis B virus core particles: Outlook 2016].

    Science.gov (United States)

    Pumpens, P; Grens, E

    2016-01-01

    This review article is a continuation of the paper "Hepatitis B core particles as a universal display model: a structure-function basis for development" written by Pumpens P. and Grens E., ordered by Professor Lev Kisselev and published in FEBS Letters, 1999, 442, 1-6. The past 17 years have strengthened the paper's finding that the human hepatitis B virus core protein, along with other Hepadnaviridae family member core proteins, is a mysterious, multifunctional protein. The core gene of the Hepadnaviridae genome encodes five partially collinear proteins. The most important of these is the HBV core protein p21, or HBc. It can self-assemble by forming viral HBc particles, but also plays a crucial role in the regulation of viral replication. Since 1986, the HBc protein has been one of the first and the most successful tools of the virus-like particle (VLP) technology. Later, the woodchuck hepatitis virus core protein (WHc) was also used as a VLP carrier. The Hepadnaviridae core proteins remain favourite VLP candidates for the knowledge-based design of future vaccines, gene therapy vectors, specifically targeted nanocontainers, and other modern nanotechnological tools for prospective medical use.

  11. Control of the Speed of a Light-Induced Spin Transition through Mesoscale Core-Shell Architecture.

    Science.gov (United States)

    Felts, Ashley C; Slimani, Ahmed; Cain, John M; Andrus, Matthew J; Ahir, Akhil R; Abboud, Khalil A; Meisel, Mark W; Boukheddaden, Kamel; Talham, Daniel R

    2018-05-02

    The rate of the light-induced spin transition in a coordination polymer network solid dramatically increases when included as the core in mesoscale core-shell particles. A series of photomagnetic coordination polymer core-shell heterostructures, based on the light-switchable Rb a Co b [Fe(CN) 6 ] c · mH 2 O (RbCoFe-PBA) as core with the isostructural K j Ni k [Cr(CN) 6 ] l · nH 2 O (KNiCr-PBA) as shell, are studied using temperature-dependent powder X-ray diffraction and SQUID magnetometry. The core RbCoFe-PBA exhibits a charge transfer-induced spin transition (CTIST), which can be thermally and optically induced. When coupled to the shell, the rate of the optically induced transition from low spin to high spin increases. Isothermal relaxation from the optically induced high spin state of the core back to the low spin state and activation energies associated with the transition between these states were measured. The presence of a shell decreases the activation energy, which is associated with the elastic properties of the core. Numerical simulations using an electro-elastic model for the spin transition in core-shell particles supports the findings, demonstrating how coupling of the core to the shell changes the elastic properties of the system. The ability to tune the rate of optically induced magnetic and structural phase transitions through control of mesoscale architecture presents a new approach to the development of photoswitchable materials with tailored properties.

  12. Statistical study of particle acceleration in the core of foreshock transients

    OpenAIRE

    Liu, Terry Z.; Angelopoulos, Vassilis; Hietala, Heli; Wilson III, Lynn B.

    2017-01-01

    Several types of foreshock transients upstream of Earth's bow shock possessing a tenuous, hot core have been observed and simulated. Because of the low dynamic pressure in their cores, these phenomena can significantly disturb the bow shock and the magnetosphere-ionosphere system. Recent observations have also demonstrated that foreshock transients can accelerate particles which, when transported earthward, can affect space weather. Understanding the potential of foreshock transients to accel...

  13. How to Determine the Core-Shell Nature in Bimetallic Catalyst Particles?

    Directory of Open Access Journals (Sweden)

    Emma Westsson

    2014-11-01

    Full Text Available Nanometer-sized materials have significantly different chemical and physical properties compared to bulk material. However, these properties do not only depend on the elemental composition but also on the structure, shape, size and arrangement. Hence, it is not only of great importance to develop synthesis routes that enable control over the final structure but also characterization strategies that verify the exact nature of the nanoparticles obtained. Here, we consider the verification of contemporary synthesis strategies for the preparation of bimetallic core-shell particles in particular in relation to potential particle structures, such as partial absence of core, alloying and raspberry-like surface. It is discussed what properties must be investigated in order to fully confirm a covering, pin-hole free shell and which characterization techniques can provide such information. Not uncommonly, characterization strategies of core-shell particles rely heavily on visual imaging like transmission electron microscopy. The strengths and weaknesses of various techniques based on scattering, diffraction, transmission and absorption for investigating core-shell particles are discussed and, in particular, cases where structural ambiguities still remain will be highlighted. Our main conclusion is that for particles with extremely thin or mono-layered shells—i.e., structures outside the limitation of most imaging techniques—other strategies, not involving spectroscopy or imaging, are to be employed. We will provide a specific example of Fe-Pt core-shell particles prepared in bicontinuous microemulsion and point out the difficulties that arise in the characterization process of such particles.

  14. The effect of particle-hole interaction on the XPS core-hole spectrum

    International Nuclear Information System (INIS)

    Ohno, Masahide; Sjoegren, Lennart

    2004-01-01

    How the effective particle-hole interaction energy, U, or the polarization effect on a secondary electron in a final two-hole one-particle (2h1p) state created by the Coster-Kronig (CK) transition can solely affect the density of the CK particle states and consequently the core-hole spectral function, is discussed. The X-ray photoelectron spectroscopy (XPS) core-hole spectrum is predominantly governed by the unperturbed initial core-hole energy relative to the zero-point energy. At the latter energy, the real part of the initial core-hole self-energy becomes zero (no relaxation energy shift) and the imaginary part (the lifetime broadening) approximately maximizes. The zero-point energy relative to the double-ionization threshold energy is governed by the ratio of U relative to the bandwidth of the CK continuum. As an example, we study the 5p XPS spectra of atomic Ra (Z=88), Th (Z=90) and U (Z=92). The spectra are interpreted in terms of the change in the unperturbed initial core-hole energy relative to the zero-point energy. We explain why in general an ab initio atomic many-body calculation can provide an overall good description of solid-state spectra predominantly governed by the atomic-like localized core-hole dynamics. We explain this in terms of the change from free atom to metal in both U and the zero-point energy (self-energy)

  15. Controlled Release from Core-Shell Nanoporous Silica Particles for Corrosion Inhibition of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Xingmao Jiang

    2011-01-01

    Full Text Available Cerium (Ce corrosion inhibitors were encapsulated into hexagonally ordered nanoporous silica particles via single-step aerosol-assisted self-assembly. The core/shell structured particles are effective for corrosion inhibition of aluminum alloy AA2024-T3. Numerical simulation proved that the core-shell nanostructure delays the release process. The effective diffusion coefficient elucidated from release data for monodisperse particles in water was 1.0×10−14 m2s for Ce3+ compared to 2.5×10−13 m2s for NaCl. The pore size, pore surface chemistry, and the inhibitor solubility are crucial factors for the application. Microporous hydrophobic particles encapsulating a less soluble corrosion inhibitor are desirable for long-term corrosion inhibition.

  16. Controlled Release from Core-Shell Nano porous Silica Particles for Corrosion Inhibition of Aluminum Alloys

    International Nuclear Information System (INIS)

    Jiang, X.; Rathod, Sh.; Shah, P.; Brinker, C.J.; Jiang, X.; Jiang, Y.; Liu, N.; Xu, H.; Brinker, C.J.

    2011-01-01

    Cerium (Ce) corrosion inhibitors were encapsulated into hexagonally ordered nanoporous silica particles via single-step aerosol-assisted self-assembly. The core/shell structured particles are effective for corrosion inhibition of aluminum alloy AA2024-T3. Numerical simulation proved that the core-shell nanostructure delays the release process. The effective diffusion coefficient elucidated from release data for monodisperse particles in water was 1.0x10-14 m 2 s for Ce 3+ compared to 2.5x10-13 m 2 s for NaCl. The pore size, pore surface chemistry, and the inhibitor solubility are crucial factors for the application. Microporous hydrophobic particles encapsulating a less soluble corrosion inhibitor are desirable for long-term corrosion inhibition.

  17. In Vitro-Assembled Alphavirus Core-Like Particles Maintain a Structure Similar to That of Nucleocapsid Cores in Mature Virus

    OpenAIRE

    Mukhopadhyay, Suchetana; Chipman, Paul R.; Hong, Eunmee M.; Kuhn, Richard J.; Rossmann, Michael G.

    2002-01-01

    In vitro-assembled core-like particles produced from alphavirus capsid protein and nucleic acid were studied by cryoelectron microscopy. These particles were found to have a diameter of 420 Å with 240 copies of the capsid protein arranged in a T=4 icosahedral surface lattice, similar to the nucleocapsid core in mature virions. However, when the particles were subjected to gentle purification procedures, they were damaged, preventing generation of reliable structural information. Similarly, pu...

  18. Mechanism of 238U disintegration induced by relativistic particles

    International Nuclear Information System (INIS)

    Andronenko, L.N.; Zhdanov, A.A.; Kravtsov, A.V.; Solyakin, G.E.

    2002-01-01

    In heavy-nucleus disintegration induced by a relativistic projectile particle, the production of collinear massive fragments accompanied by numerous charged particles and neutrons is explained in terms of the mechanism of projectile-momentum compensation due to the emission of a particle whose mass is greater than the projectile mass

  19. Diffusion of finite-sized hard-core interacting particles in a one-dimensional box: Tagged particle dynamics.

    Science.gov (United States)

    Lizana, L; Ambjörnsson, T

    2009-11-01

    We solve a nonequilibrium statistical-mechanics problem exactly, namely, the single-file dynamics of N hard-core interacting particles (the particles cannot pass each other) of size Delta diffusing in a one-dimensional system of finite length L with reflecting boundaries at the ends. We obtain an exact expression for the conditional probability density function rhoT(yT,t|yT,0) that a tagged particle T (T=1,...,N) is at position yT at time t given that it at time t=0 was at position yT,0. Using a Bethe ansatz we obtain the N -particle probability density function and, by integrating out the coordinates (and averaging over initial positions) of all particles but particle T , we arrive at an exact expression for rhoT(yT,t|yT,0) in terms of Jacobi polynomials or hypergeometric functions. Going beyond previous studies, we consider the asymptotic limit of large N , maintaining L finite, using a nonstandard asymptotic technique. We derive an exact expression for rhoT(yT,t|yT,0) for a tagged particle located roughly in the middle of the system, from which we find that there are three time regimes of interest for finite-sized systems: (A) for times much smaller than the collision time tparticle concentration and D is the diffusion constant for each particle, the tagged particle undergoes a normal diffusion; (B) for times much larger than the collision time t >taucoll but times smaller than the equilibrium time ttaue , rhoT(yT,t|yT,0) approaches a polynomial-type equilibrium probability density function. Notably, only regimes (A) and (B) are found in the previously considered infinite systems.

  20. Two quasi-particle excitations with particle-hole core polarization in even-even single closed shell nuclei

    International Nuclear Information System (INIS)

    Gillet, V.; Giraud, B.; Rho, M.

    1976-01-01

    The energy levels and transition properties of the even-even N=28, 50 isotones and Z=28, 50, 82 isotopes are calculated in the framework of the Tamm-Dancoff and Random Phase Approximation, with an effective central interaction in an extended space consisting of two quasi-particle configurations for the open shell and particle-hole configurations for the closed core. Using the results of the Inverse Gap Equation Method, practically all the necessary input data (single quasi-particle energies, force strength) are extracted from the odd-mass nuclei. The ratios of the force components are kept at fixed values for all studied nuclei and no effective charge is used. An overall excellent agreement is obtained for the energies of the vibrational states. On the other hand, while the transition properties of the 3 - states are always well reproduced, those of the 2 + and 4 + states are often too small by about one order of magnitude [fr

  1. Particle shape accounts for instrumental discrepancy in ice core dust size distributions

    Science.gov (United States)

    Folden Simonsen, Marius; Cremonesi, Llorenç; Baccolo, Giovanni; Bosch, Samuel; Delmonte, Barbara; Erhardt, Tobias; Kjær, Helle Astrid; Potenza, Marco; Svensson, Anders; Vallelonga, Paul

    2018-05-01

    The Klotz Abakus laser sensor and the Coulter counter are both used for measuring the size distribution of insoluble mineral dust particles in ice cores. While the Coulter counter measures particle volume accurately, the equivalent Abakus instrument measurement deviates substantially from the Coulter counter. We show that the difference between the Abakus and the Coulter counter measurements is mainly caused by the irregular shape of dust particles in ice core samples. The irregular shape means that a new calibration routine based on standard spheres is necessary for obtaining fully comparable data. This new calibration routine gives an increased accuracy to Abakus measurements, which may improve future ice core record intercomparisons. We derived an analytical model for extracting the aspect ratio of dust particles from the difference between Abakus and Coulter counter data. For verification, we measured the aspect ratio of the same samples directly using a single-particle extinction and scattering instrument. The results demonstrate that the model is accurate enough to discern between samples of aspect ratio 0.3 and 0.4 using only the comparison of Abakus and Coulter counter data.

  2. Fracture resistance improvement of polypropylene by joint action of core-shell particles and nucleating agent

    International Nuclear Information System (INIS)

    Yang Gang; Han Liang; Ding Haifeng; Wu Haiyan; Huang Ting; Li Xiaoxi; Wang Yong

    2011-01-01

    Research highlights: →The core-shell particles, which were prepared from melt blending of POE and nano-CaCO 3 , and different nucleating agents (α-form NA or β-form NA) were first introduced into PP to prepare the super toughened PP materials. →NAs control the crystalline structures of PP matrix including the spherulites diameter and the crystal form. →NAs and core-shell particles exhibit apparent joint effect in improving the fracture resistance of PP. - Abstract: As a serial work about the fracture resistance improvement of polypropylene (PP), this work reports the joint effect of core-shell particles and nucleating agent (NA) on the microstructure and fracture resistance of PP. Core-shell particles were prepared through melt blending of ethylene-octene copolymer (POE) and calcium carbonate (CaCO 3 ). Different NA, i.e. α-form NA (P-tert-butylbenzoic acid-Al, MD-NA-28) and β-form NA (aryl amides compound, TMB-5) were introduced into PP matrix to control the crystalline structure. The phase morphology of POE and the distribution of CaCO 3 were characterized by using scanning electron microscope (SEM), and the crystallization behavior of PP matrix were investigated by using differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarization optical microscope (POM). The mechanical properties were obtained through universal tensile measurement and notched Izod impact measurement. Surprisingly, the results show that through addition of so-called core-shell particles and NA simultaneously, the fracture resistance of PP can be dramatically improved.

  3. Core-Shell Particles as Building Blocks for Systems with High Duality Symmetry

    Science.gov (United States)

    Rahimzadegan, Aso; Rockstuhl, Carsten; Fernandez-Corbaton, Ivan

    2018-05-01

    Material electromagnetic duality symmetry requires a system to have equal electric and magnetic responses. Intrinsically dual materials that meet the duality conditions at the level of the constitutive relations do not exist in many frequency bands. Nevertheless, discrete objects like metallic helices and homogeneous dielectric spheres can be engineered to approximate the dual behavior. We exploit the extra degrees of freedom of a core-shell dielectric sphere in a particle optimization procedure. The duality symmetry of the resulting particle is more than 1 order of magnitude better than previously reported nonmagnetic objects. We use T -matrix-based multiscattering techniques to show that the improvement is transferred onto the duality symmetry of composite objects when the core-shell particle is used as a building block instead of homogeneous spheres. These results are relevant for the fashioning of systems with high duality symmetry, which are required for some technologically important effects.

  4. Existence of core localized toroidicity-induced Alfven eigenmode

    International Nuclear Information System (INIS)

    Fu, G.Y.

    1995-02-01

    The core-localized toroidicity-induced Alfven eigenmode (TAE) is shown to exist at finite plasma pressure due to finite aspect ratio effects in tokamak plasma. The new critical beta for the existence of the TAE mode is given by α∼ 3ε + 2s 2 , where ε = r/R is the inverse aspect ratio, s is the magnetic shear and α = -Rq 2 dβ/dr is the normalized pressure gradient. In contrast, previous critical α is given by α ∼ s 2 . In the limit of s << √r/R, the new critical α is greatly enhanced by the finite aspect ratio effects

  5. Partial coherence in the core/halo picture of Bose-Einstein n-particle correlations

    OpenAIRE

    Csorgo, T.; Lorstad, B.; Schmidt-Sorensen, J.; Ster, A.

    1998-01-01

    We study the influence of a possible coherent component in the boson source on the two-, three- and $n$-particle correlation functions in a generalized core/halo type of boson-emitting source. In particular, a simple formula is presented for the strengh of the $n$-particle correlation functions for such systems. Graph rules are obtained to evaluate the correlation functions of arbitrary high order. The importance of experimental determination of the 4-th and 5-th order Bose-Einstein correlati...

  6. Functional Polymer Opals and Porous Materials by Shear-Induced Assembly of Tailor-Made Particles.

    Science.gov (United States)

    Gallei, Markus

    2018-02-01

    Photonic band-gap materials attract enormous attention as potential candidates for a steadily increasing variety of applications. Based on the preparation of easily scalable monodisperse colloids, such optically attractive photonic materials can be prepared by an inexpensive and convenient bottom-up process. Artificial polymer opals can be prepared by shear-induced assembly of core/shell particles, yielding reversibly stretch-tunable materials with intriguing structural colors. This feature article highlights recent developments of core/shell particle design and shear-induced opal formation with focus on the combination of hard and soft materials as well as crosslinking strategies. Structure formation of opal materials relies on both the tailored core/shell architecture and the parameters for polymer processing. The emphasis of this feature article is on elucidating the particle design and incorporation of addressable moieties, i.e., stimuli-responsive polymers as well as elaborated crosslinking strategies for the preparation of smart (inverse) opal films, inorganic/organic opals, and ceramic precursors by shear-induced ordering. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Chemical resistance of core-shell particles (PS/PMMA polymerized by seeded suspension

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Belchior Ribeiro

    2017-09-01

    Full Text Available Abstract Core-shell particles were produced on seeded suspension polymerization by using polystyrene (PS as polymer core, or seed, and methyl methacrylate (MMA as the shell forming monomer. Two synthesis routes were evaluated by varying the PS seed conversion before MMA addition. The main purpose of this work was to investigate the influence of synthesis routes on the morphology and chemical resistance of the resulting particles. 1H NMR spectroscopy showed that the use of PS seeds with lower conversion led to the formation of higher amount of poly(styrene-co-MMA. The copolymer acted as a compatibilizer, decreasing the interfacial energy between both homopolymers. As a consequence, a larger amount of reduced PMMA cluster were formed, as was revealed by TEM measurements. Samples in this system showed enhanced resistance to cyclohexane attack compared with pure PS, with a PS extraction of only 37% after 54 hours test.

  8. Chemical resistance of core-shell particles (PS/PMMA) polymerized by seeded suspension

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Luiz Fernando Belchior; Machado, Ricardo Antonio Francisco, E-mail: ricardo.machado@ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Departamento de Engenharia de Materiais; Gonçalves, Odinei Hess [Universidade Técnológica Federal do Paraná(UTFPR), Campo Mourão, PR (Brazil); Marangoni, Cintia [Universidade Federal de Santa Catarina (UFSC), Blumenau, SC (Brazil); Motz, Günter [Lehrstuhl Keramische Werkstoffe, Universität Bayreuth (Germany)

    2017-07-01

    Core-shell particles were produced on seeded suspension polymerization by using polystyrene (PS) as polymer core, or seed, and methyl methacrylate (MMA) as the shell forming monomer. Two synthesis routes were evaluated by varying the PS seed conversion before MMA addition. The main purpose of this work was to investigate the influence of synthesis routes on the morphology and chemical resistance of the resulting particles. {sup 1}H NMR spectroscopy showed that the use of PS seeds with lower conversion led to the formation of higher amount of poly(styrene-co-MMA). The copolymer acted as a compatibilizer, decreasing the interfacial energy between both homopolymers. As a consequence, a larger amount of reduced PMMA cluster were formed, as was revealed by TEM measurements. Samples in this system showed enhanced resistance to cyclohexane attack compared with pure PS, with a PS extraction of only 37% after 54 hours test. (author)

  9. Facile synthesis of silver immobilized-poly(methyl methacrylate)/polyethyleneimine core-shell particle composites

    Energy Technology Data Exchange (ETDEWEB)

    Jenjob, Somkieath [Department of Chemistry, Faculty of Science, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170 (Thailand); Center of Excellence for Innovation in Chemistry (PERCH-CIC), Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Ratchathewi, Bangkok 10400 (Thailand); Tharawut, Teeralak [Department of Chemistry, Faculty of Science, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170 (Thailand); Sunintaboon, Panya, E-mail: panya.sun@mahidol.ac.th [Department of Chemistry, Faculty of Science, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170 (Thailand); Center of Excellence for Innovation in Chemistry (PERCH-CIC), Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Ratchathewi, Bangkok 10400 (Thailand); Center for Alternative Energy, Faculty of Science, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170 (Thailand)

    2012-10-01

    A facile route to synthesize silver-embedded-poly(methyl methacrylate)/polyethyleneimine (PMMA/PEI-Ag) core-shell particle composites was illustrated in this present work. PMMA/PEI core-shell particle templates were first prepared by a surfactant-free emulsion polymerization. PEI on the templates' surface was further used to complex and reduce Ag{sup +} ions (from silver nitrate solution) to silver nanoparticles (AgNPs) at ambient temperature, resulting in the PMMA/PEI-Ag particle composites. The formation of AgNPs was affected by the pHs of the reaction medium. The pH of reaction medium at 6.5 was optimal for the formation of PMMA/PEI-Ag with good colloidal stability, which was confirmed by size and size distribution, FTIR spectroscopy, UV-vis spectroscopy and X-ray diffraction. Moreover, the amount of AgNO{sub 3} solution (4.17-12.50 g) was found to affect the formation of AgNPs. Transmission electron microscopy (TEM) indicated that the AgNPs were incorporated in the PMMA/PEI core-shell matrix, and had 6-10 nm in diameter. AgNPs immobilized on PMMA/PEI core-shell particles were also investigated by energy dispersive X-ray spectroscopy analysis mode extended from scanning electron microscopy (SEM/EDS). Furthermore, the presence of AgNPs was found to influence the thermal degradation behavior of PMMA/PEI particle composites as observed through thermogravimetric analysis (TGA). Highlights: Black-Right-Pointing-Pointer A 2-step synthesis of Ag immobilized-PMMA/PEI particle composites was shown. Black-Right-Pointing-Pointer PMMA/PEI core-shell templates were first formed and PEI assisted AgNP formation. Black-Right-Pointing-Pointer Formation of PMMA/PEI-Ag was affected by pH of medium and amount of AgNO{sub 3}. Black-Right-Pointing-Pointer PMMA/PEI-Ag can be confirmed by color change, UV-vis, TEM, SEM with EDS, and X-ray. Black-Right-Pointing-Pointer Effect of AgNPs on thermal degradation of PMMA/PEI-Ag can be observed through TGA.

  10. ZnO core spike particles and nano-networks and their wide range of applications

    Science.gov (United States)

    Wille, S.; Mishra, Y. K.; Gedamu, D.; Kaps, S.; Jin, X.; Koschine, T.; Bathnagar, A.; Adelung, R.

    2011-05-01

    In our approach we are producing a polymer composite material with ZnO core spike particles as concave fillers. The core spike particles are synthesized by a high throughput method. Using PDMS (Polydimethylsiloxane) as a matrix material the core spike particles achieve not only a high mechanical reinforcement but also influence other material properties in a very interesting way, making such a composite very interesting for a wide range of applications. In a very similar synthesis route a nanoscopic ZnO-network is produced. As a ceramic this network can withstand high temperatures like 1300 K. In addition this material is quite elastic. To find a material with these two properties is a really difficult task, as polymers tend to decompose already at lower temperatures and metals melt. Especially under ambient conditions, often oxygen creates a problem for metals at these temperatures. If this material is at the same time a semiconductor, it has a high potential as a multifunctional material. Ceramic or classical semiconductors like III-V or IIVI type are high temperature stable, but typically brittle. This is different on the nanoscale. Even semiconductor wires like silicon with a very small diameter do not easily built up enough stress that leads to a failure while being bent, because in a first order approximation the maximum stress of a fiber scales with its diameter.

  11. Monte Carlo simulation of particle-induced bit upsets

    Science.gov (United States)

    Wrobel, Frédéric; Touboul, Antoine; Vaillé, Jean-Roch; Boch, Jérôme; Saigné, Frédéric

    2017-09-01

    We investigate the issue of radiation-induced failures in electronic devices by developing a Monte Carlo tool called MC-Oracle. It is able to transport the particles in device, to calculate the energy deposited in the sensitive region of the device and to calculate the transient current induced by the primary particle and the secondary particles produced during nuclear reactions. We compare our simulation results with SRAM experiments irradiated with neutrons, protons and ions. The agreement is very good and shows that it is possible to predict the soft error rate (SER) for a given device in a given environment.

  12. Monte Carlo simulation of particle-induced bit upsets

    Directory of Open Access Journals (Sweden)

    Wrobel Frédéric

    2017-01-01

    Full Text Available We investigate the issue of radiation-induced failures in electronic devices by developing a Monte Carlo tool called MC-Oracle. It is able to transport the particles in device, to calculate the energy deposited in the sensitive region of the device and to calculate the transient current induced by the primary particle and the secondary particles produced during nuclear reactions. We compare our simulation results with SRAM experiments irradiated with neutrons, protons and ions. The agreement is very good and shows that it is possible to predict the soft error rate (SER for a given device in a given environment.

  13. Controllable fabrication and characterization of biocompatible core-shell particles and hollow capsules as drug carrier

    Science.gov (United States)

    Hao, Lingyun; Gong, Xinglong; Xuan, Shouhu; Zhang, Hong; Gong, Xiuqing; Jiang, Wanquan; Chen, Zuyao

    2006-10-01

    SiO 2@CdSe core-shell particles were fabricated by controllable deposition CdSe nanoparticles on silica colloidal spheres. Step-wise coating process was tracked by the TEM and XRD measurements. In addition, SiO 2@CdSe/polypyrrole(PPy) multi-composite particles were synthesized based on the as-prepared SiO 2@CdSe particles by cationic polymerization. The direct electrochemistry of myoglobin (Mb) could be performed by immobilizing Mb on the surface of SiO 2@CdSe particles. Immobilized with Mb, SiO 2@CdSe/PPy-Mb also displayed good bioelectrochemical activity. It confirmed the good biocompatible property of the materials with protein. CdSe hollow capsules were further obtained as the removal of the cores of SiO 2@CdSe spheres. Hollow and porous character of CdSe sub-meter size capsules made them becoming hopeful candidates as drug carriers. Doxorubicin, a typical an antineoplastic drug, was introduced into the capsules. A good sustained drug release behavior of the loading capsules was discovered via performing a release test in the PBS buffer (pH 7.4) solution at 310 k. Furthermore, SiO 2@CdSe/PPy could be converted to various smart hollow capsules via selectively removal of their relevant components.

  14. Ripple induced trapped particle loss in tokamaks

    International Nuclear Information System (INIS)

    White, R.B.

    1996-05-01

    The threshold for stochastic transport of high energy trapped particles in a tokamak due to toroidal field ripple is calculated by explicit construction of primary resonances, and a numerical examination of the route to chaos. Critical field ripple amplitude is determined for loss. The expression is given in magnetic coordinates and makes no assumptions regarding shape or up-down symmetry. An algorithm is developed including the effects of prompt axisymmetric orbit loss, ripple trapping, convective banana flow, and stochastic ripple loss, which gives accurate ripple loss predictions for representative Tokamak Fusion Test Reactor and International Thermonuclear Experimental Reactor equilibria. The algorithm is extended to include the effects of collisions and drag, allowing rapid estimation of alpha particle loss in tokamaks

  15. Inducing Lift on Spherical Particles by Traveling Magnetic Fields

    Science.gov (United States)

    Mazuruk, Konstantin; Grugel, Richard N.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Gravity induced sedimentation of suspensions is a serious drawback to many materials and biotechnology processes, a factor that can, in principle, be overcome by utilizing an opposing Lorentz body force. In this work we demonstrate the utility of employing a traveling magnetic field (TMF) to induce a lifting force on particles dispersed in the fluid. Theoretically, a model has been developed to ascertain the net force, induced by TMF, acting on a spherical body as a function of the fluid medium's electrical conductivity and other parameters. Experimentally, the model is compared to optical observations of particle motion in the presence of TMF.

  16. A Small Modular Reactor Core Design using FCM Fuel and BISO BP particles

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jae Yeon; Hwang, Dae Hee; Yoo, Ho Seong; Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of)

    2016-10-15

    The objective of this work is to design a PWR small modular reactor which employs the advanced fuel technology of FCM particle fuels including BISO burnable poisons and advanced cladding of SiC in order to improve the fuel economy and safety by increasing fuel burnup and temperature, and by reducing hydrogen generation under accidents. Recently, many countries including USA have launched projects to develop the accident tolerant fuels (ATF) which can cope with the accidents such as LOCA (Loss of Coolant Accident). In general, the ATF fuels are required to meet the PWR operational, safety, and fuel cycle constraints which include enhanced burnup, lower or no generation of hydrogen, lower operating temperatures, and enhanced retention of fission products. Another stream of research and development in nuclear society is to develop advanced small modular reactors in order to improve inherent passive safety and to reduce the risk of large capital investment. In this work, a small PWR modular reactor core was neutronically designed and analyzed. The SMR core employs new 13x13 fuel assemblies which are loaded with thick FCM fuel rods in which TRISO fuel particles AO and also the first cycle has the AOs which are within the typical design limit. Also, this figure shows that the evolutions of AO for the cycles 6 and 7 are nearly the same. we considered the SiC cladding for reduction of hydrogen generation under accidents. From the results of core design and analysis, it is shown that the core has long cycle length of 732 -1191 EFPDs, high discharge burnup of 101-105 MWD/kg, low power peaking factors, low axial offsets, negative MTCs, and large shutdown margins except for BOC of the first cycle. So, it can be concluded that the new SMR core is neutronically feasible.

  17. A Small Modular Reactor Core Design using FCM Fuel and BISO BP particles

    International Nuclear Information System (INIS)

    Choi, Jae Yeon; Hwang, Dae Hee; Yoo, Ho Seong; Hong, Ser Gi

    2016-01-01

    The objective of this work is to design a PWR small modular reactor which employs the advanced fuel technology of FCM particle fuels including BISO burnable poisons and advanced cladding of SiC in order to improve the fuel economy and safety by increasing fuel burnup and temperature, and by reducing hydrogen generation under accidents. Recently, many countries including USA have launched projects to develop the accident tolerant fuels (ATF) which can cope with the accidents such as LOCA (Loss of Coolant Accident). In general, the ATF fuels are required to meet the PWR operational, safety, and fuel cycle constraints which include enhanced burnup, lower or no generation of hydrogen, lower operating temperatures, and enhanced retention of fission products. Another stream of research and development in nuclear society is to develop advanced small modular reactors in order to improve inherent passive safety and to reduce the risk of large capital investment. In this work, a small PWR modular reactor core was neutronically designed and analyzed. The SMR core employs new 13x13 fuel assemblies which are loaded with thick FCM fuel rods in which TRISO fuel particles AO and also the first cycle has the AOs which are within the typical design limit. Also, this figure shows that the evolutions of AO for the cycles 6 and 7 are nearly the same. we considered the SiC cladding for reduction of hydrogen generation under accidents. From the results of core design and analysis, it is shown that the core has long cycle length of 732 -1191 EFPDs, high discharge burnup of 101-105 MWD/kg, low power peaking factors, low axial offsets, negative MTCs, and large shutdown margins except for BOC of the first cycle. So, it can be concluded that the new SMR core is neutronically feasible

  18. Relativistic Photon Induced Processes of Composite Particles

    International Nuclear Information System (INIS)

    Ribeiro-Silva, C.I; Curado, E. M. F.; Rego-Monteiro, M. A.

    2007-01-01

    We consider a complex quantum field theory based on a generalized Heisenberg[1] algebra, which describes at the space-time a spin less composite particle. We compute the perturbative series and the cross section of the scattering process 2 γ→φ - , φ + up to second order in the coupling constant and we find a further contribution due to the structure of the composite pion which is described here phenomenologically by the generalized algebra. We compare the results of this study with available experimental data. (Author)

  19. Molecular Mechanisms of Particle Ration Induced Apoptosis in Lymphocyte

    Science.gov (United States)

    Shi, Yufang

    Space radiation, composed of high-energy charged nuclei (HZE particles) and protons, has been previously shown to severely impact immune homeostasis in mice. To determine the molecular mechanisms that mediate acute lymphocyte depletion following exposure to HZE particle radiation mice were exposed to particle radiation beams at Brookhaven National Laboratory. We found that mice given whole body 5 6Fe particle irradiation (1GeV /n) had dose-dependent losses in total lymphocyte numbers in the spleen and thymus (using 200, 100 and 50 cGy), with thymocytes being more sensitive than splenocytes. All phenotypic subsets were reduced in number. In general, T cells and B cells were equally sensitive, while CD8+ T cells were more senstive than CD4+ T cells. In the thymus, immature CD4+CD8+ double-positive thymocytes were exquisitely sensitive to radiation-induced losses, single-positive CD4 or CD8 cells were less sensitive, and the least mature double negative cells were resistant. Irradiation of mice deficient in genes encoding essential apoptosis-inducing proteins revealed that the mechanism of lymphocyte depletion is independent of Fas ligand and TRAIL (TNF-ralated apoptosis-inducing ligand), in contrast to γ-radiation-induced lymphocyte losses which require the Fas-FasL pathway. Using inhibitors in vitro, lymphocyte apoptosis induced by HZE particle radiation was found to be caspase dependent, and not involve nitric oxide or oxygen free radicals.

  20. Isostructural solid-solid phase transition in monolayers of soft core-shell particles at fluid interfaces: structure and mechanics.

    Science.gov (United States)

    Rey, Marcel; Fernández-Rodríguez, Miguel Ángel; Steinacher, Mathias; Scheidegger, Laura; Geisel, Karen; Richtering, Walter; Squires, Todd M; Isa, Lucio

    2016-04-21

    We have studied the complete two-dimensional phase diagram of a core-shell microgel-laden fluid interface by synchronizing its compression with the deposition of the interfacial monolayer. Applying a new protocol, different positions on the substrate correspond to different values of the monolayer surface pressure and specific area. Analyzing the microstructure of the deposited monolayers, we discovered an isostructural solid-solid phase transition between two crystalline phases with the same hexagonal symmetry, but with two different lattice constants. The two phases corresponded to shell-shell and core-core inter-particle contacts, respectively; with increasing surface pressure the former mechanically failed enabling the particle cores to come into contact. In the phase-transition region, clusters of particles in core-core contacts nucleate, melting the surrounding shell-shell crystal, until the whole monolayer moves into the second phase. We furthermore measured the interfacial rheology of the monolayers as a function of the surface pressure using an interfacial microdisk rheometer. The interfaces always showed a strong elastic response, with a dip in the shear elastic modulus in correspondence with the melting of the shell-shell phase, followed by a steep increase upon the formation of a percolating network of the core-core contacts. These results demonstrate that the core-shell nature of the particles leads to a rich mechanical and structural behavior that can be externally tuned by compressing the interface, indicating new routes for applications, e.g. in surface patterning or emulsion stabilization.

  1. Vaccine delivery system for tuberculosis based on nano-sized hepatitis B virus core protein particles

    Directory of Open Access Journals (Sweden)

    Dhanasooraj D

    2013-02-01

    Full Text Available Dhananjayan Dhanasooraj, R Ajay Kumar, Sathish MundayoorMycobacterium Research Group, Rajiv Gandhi Centre for Biotechnology, Kerala, IndiaAbstract: Nano-sized hepatitis B virus core virus-like particles (HBc-VLP are suitable for uptake by antigen-presenting cells. Mycobacterium tuberculosis antigen culture filtrate protein 10 (CFP-10 is an important vaccine candidate against tuberculosis. The purified antigen shows low immune response without adjuvant and tends to have low protective efficacy. The present study is based on the assumption that expression of these proteins on HBc nanoparticles would provide higher protection when compared to the native antigen alone. The cfp-10 gene was expressed as a fusion on the major immunodominant region of HBc-VLP, and the immune response in Balb/c mice was studied and compared to pure proteins, a mixture of antigens, and fusion protein-VLP, all without using any adjuvant. The humoral, cytokine, and splenocyte cell proliferation responses suggested that the HBc-VLP bearing CFP-10 generated an antigen-specific immune response in a Th1-dependent manner. By virtue of its self-adjuvant nature and ability to form nano-sized particles, HBc-VLPs are an excellent vaccine delivery system for use with subunit protein antigens identified in the course of recent vaccine research.Keywords: Mycobacterium tuberculosis, VLP, hepatitis B virus core particle, CFP-10, self-adjuvant, vaccine delivery

  2. Chromosomal aberrations induced by alpha particles

    International Nuclear Information System (INIS)

    Guerrero C, C.; Brena V, M.

    2005-01-01

    The chromosomal aberrations produced by the ionizing radiation are commonly used when it is necessary to establish the exposure dose of an individual, it is a study that is used like complement of the traditional physical systems and its application is only in cases in that there is doubt about what indicates the conventional dosimetry. The biological dosimetry is based on the frequency of aberrations in the chromosomes of the lymphocytes of the individual in study and the dose is calculated taking like reference to the dose-response curves previously generated In vitro. A case of apparent over-exposure to alpha particles to which is practiced analysis of chromosomal aberrations to settle down if in fact there was exposure and as much as possible, to determine the presumed dose is presented. (Author)

  3. Improved microbial growth inhibition activity of bio-surfactant induced Ag–TiO{sub 2} core shell nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nithyadevi, D. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Kumar, P. Suresh [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Ponpandian, N.; Viswanathan, C. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Meena, P. [Department of Physics, PSGR Krishnammal college for women, Coimbatore 641 004 (India)

    2015-02-01

    Graphical abstract: - Highlights: • TiO{sub 2} nanoparticles were synthesized by hydrolysis process and Ag nanoparticles were prepared by using hydrazine reduction method. • Ag–TiO{sub 2} core shell nanoparticles were synthesized by reverse micelle method. • Coatings of TiO{sub 2} shell leads to decrease the usage of silver particles and also it reduces the release of silver ions from the matrix. • Optimum ratio of TiO{sub 2} particles: Ag atoms are needed for better antibacterial activity. • Sodium alginate (Bio-copolymer) induced core shell nanoparticles results 100% cell growth inhibition toward Staphylococcus aureus. - Abstract: Surfactant induced silver–titanium dioxide core shell nanoparticles within the size range of 10–50 nm were applied in the antibacterial agent to inhibit the growth of bacterial cells. The single crystalline silver was located in the core part of the composite powder and the titanium dioxide components were uniformly distributed in the shell part. HRTEM and XRD results indicated that silver was completely covered by titanium dioxide and its crystal structure was not affected after being coated by titanium dioxide. The effect of silver–titanium dioxide nanoparticles in the inhibition of bacterial cell growth was studied by means of disk diffusion method. The inhibition zone results reveal that sodium alginate induced silver–titanium dioxide nanoparticles exhibit 100% more antibacterial activity than that with cetyltrimethylbromide or without surfactant. UV–vis spectroscopic analysis showed a large concentration of silver was rapidly released into phosphate buffer solution (PBS) within a period of 1 day, with a much smaller concentration being released after this 1-day period. It was concluded that sodium alginate induced silver–titanium dioxide core shell nanoparticles could enhance long term cell growth inhibition in comparison with cetyltrimethylbromide or without surfactant. The surfactant mediated core shell

  4. Test particle modeling of wave-induced energetic electron precipitation

    International Nuclear Information System (INIS)

    Chang, H.C.; Inan, U.S.

    1985-01-01

    A test particle computer model of the precipitation of radiation belt electrons is extended to compute the dynamic energy spectrum of transient electron fluxes induced by short-duration VLF wave packets traveling along the geomagnetic field lines. The model is adapted to estimate the count rate and associated spectrum of precipitated electrons that would be observed by satellite-based particle detectors with given geometric factor and orientation with respect to the magnetic field. A constant-frequency wave pulse and a lightning-induced whistler wave packet are used as examples of the stimulating wave signals. The effects of asymmetry of particle mirror heights in the two hemispheres and the atmospheric backscatter of loss cone particles on the computed precipitated fluxes are discussed

  5. Monolithic photonic crystals created by partial coalescence of core-shell particles.

    Science.gov (United States)

    Lee, Joon-Seok; Lim, Che Ho; Yang, Seung-Man; Kim, Shin-Hyun

    2014-03-11

    Colloidal crystals and their derivatives have been intensively studied and developed during the past two decades due to their unique photonic band gap properties. However, complex fabrication procedures and low mechanical stability severely limit their practical uses. Here, we report stable photonic structures created by using colloidal building blocks composed of an inorganic core and an organic shell. The core-shell particles are convectively assembled into an opal structure, which is then subjected to thermal annealing. During the heat treatment, the inorganic cores, which are insensitive to heat, retain their regular arrangement in a face-centered cubic lattice, while the organic shells are partially fused with their neighbors; this forms a monolithic structure with high mechanical stability. The interparticle distance and therefore stop band position are precisely controlled by the annealing time; the distance decreases and the stop band blue shifts during the annealing. The composite films can be further treated to give a high contrast in the refractive index. The inorganic cores are selectively removed from the composite by wet etching, thereby providing an organic film containing regular arrays of air cavities. The high refractive index contrast of the porous structure gives rise to pronounced structural colors and high reflectivity at the stop band position.

  6. Lateral Tension-Induced Penetration of Particles into a Liposome

    Directory of Open Access Journals (Sweden)

    Kazuki Shigyou

    2017-07-01

    Full Text Available It is important that we understand the mechanism of the penetration of particles into a living cell to achieve advances in bionanotechnology, such as for treatment, visualization within a cell, and genetic modification. Although there have been many studies on the application of functional particles to cells, the basic mechanism of penetration across a biological membrane is still poorly understood. Here we used a model membrane system to demonstrate that lateral membrane tension drives particle penetration across a lipid bilayer. After the application of osmotic pressure, fully wrapped particles on a liposome surface were found to enter the liposome. We discuss the mechanism of the tension-induced penetration in terms of narrow constriction of the membrane at the neck part. The present findings are expected to provide insight into the application of particles to biological systems.

  7. Stress-induced core temperature changes in pigeons (Columba livia).

    Science.gov (United States)

    Bittencourt, Myla de Aguiar; Melleu, Fernando Falkenburger; Marino-Neto, José

    2015-02-01

    Changes in body temperature are significant physiological consequences of stressful stimuli in mammals and birds. Pigeons (Columba livia) prosper in (potentially) stressful urban environments and are common subjects in neurobehavioral studies; however, the thermal responses to stress stimuli by pigeons are poorly known. Here, we describe acute changes in the telemetrically recorded celomatic (core) temperature (Tc) in pigeons given a variety of potentially stressful stimuli, including transfer to a novel cage (ExC) leading to visual isolation from conspecifics, the presence of the experimenter (ExpR), gentle handling (H), sham intracelomatic injections (SI), and the induction of the tonic immobility (TI) response. Transfer to the ExC cage provoked short-lived hyperthermia (10-20 min) followed by a long-lasting and substantial decrease in Tc, which returned to baseline levels 2 h after the start of the test. After a 2-hour stay in the ExC, the other potentially stressful stimuli evoked only weak, marginally significant hyperthermic (ExpR, IT) or hypothermic (SI) responses. Stimuli delivered 26 h after transfer to the ExC induced definite and intense increases in Tc (ExpR, H) or hypothermic responses (SI). These Tc changes appear to be unrelated to modifications in general activity (as measured via telemetrically recorded actimetric data). Repeated testing failed to affect the hypothermic responses to the transference to the ExC, even after nine trials and at 1- or 8-day intervals, suggesting that the social (visual) isolation from conspecifics may be a strong and poorly controllable stimulus in this species. The present data indicated that stress-induced changes in Tc may be a consistent and reliable physiological parameter of stress but that they may also show stressor type-, direction- and species-specific attributes. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Parallelized Kalman-Filter-Based Reconstruction of Particle Tracks on Many-Core Processors and GPUs

    Science.gov (United States)

    Cerati, Giuseppe; Elmer, Peter; Krutelyov, Slava; Lantz, Steven; Lefebvre, Matthieu; Masciovecchio, Mario; McDermott, Kevin; Riley, Daniel; Tadel, Matevž; Wittich, Peter; Würthwein, Frank; Yagil, Avi

    2017-08-01

    For over a decade now, physical and energy constraints have limited clock speed improvements in commodity microprocessors. Instead, chipmakers have been pushed into producing lower-power, multi-core processors such as Graphical Processing Units (GPU), ARM CPUs, and Intel MICs. Broad-based efforts from manufacturers and developers have been devoted to making these processors user-friendly enough to perform general computations. However, extracting performance from a larger number of cores, as well as specialized vector or SIMD units, requires special care in algorithm design and code optimization. One of the most computationally challenging problems in high-energy particle experiments is finding and fitting the charged-particle tracks during event reconstruction. This is expected to become by far the dominant problem at the High-Luminosity Large Hadron Collider (HL-LHC), for example. Today the most common track finding methods are those based on the Kalman filter. Experience with Kalman techniques on real tracking detector systems has shown that they are robust and provide high physics performance. This is why they are currently in use at the LHC, both in the trigger and offine. Previously we reported on the significant parallel speedups that resulted from our investigations to adapt Kalman filters to track fitting and track building on Intel Xeon and Xeon Phi. Here, we discuss our progresses toward the understanding of these processors and the new developments to port the Kalman filter to NVIDIA GPUs.

  9. Parallelized Kalman-Filter-Based Reconstruction of Particle Tracks on Many-Core Processors and GPUs

    Directory of Open Access Journals (Sweden)

    Cerati Giuseppe

    2017-01-01

    Full Text Available For over a decade now, physical and energy constraints have limited clock speed improvements in commodity microprocessors. Instead, chipmakers have been pushed into producing lower-power, multi-core processors such as Graphical Processing Units (GPU, ARM CPUs, and Intel MICs. Broad-based efforts from manufacturers and developers have been devoted to making these processors user-friendly enough to perform general computations. However, extracting performance from a larger number of cores, as well as specialized vector or SIMD units, requires special care in algorithm design and code optimization. One of the most computationally challenging problems in high-energy particle experiments is finding and fitting the charged-particle tracks during event reconstruction. This is expected to become by far the dominant problem at the High-Luminosity Large Hadron Collider (HL-LHC, for example. Today the most common track finding methods are those based on the Kalman filter. Experience with Kalman techniques on real tracking detector systems has shown that they are robust and provide high physics performance. This is why they are currently in use at the LHC, both in the trigger and offine. Previously we reported on the significant parallel speedups that resulted from our investigations to adapt Kalman filters to track fitting and track building on Intel Xeon and Xeon Phi. Here, we discuss our progresses toward the understanding of these processors and the new developments to port the Kalman filter to NVIDIA GPUs.

  10. Parallelized Kalman-Filter-Based Reconstruction of Particle Tracks on Many-Core Processors and GPUs

    Energy Technology Data Exchange (ETDEWEB)

    Cerati, Giuseppe [Fermilab; Elmer, Peter [Princeton U.; Krutelyov, Slava [UC, San Diego; Lantz, Steven [Cornell U.; Lefebvre, Matthieu [Princeton U.; Masciovecchio, Mario [UC, San Diego; McDermott, Kevin [Cornell U.; Riley, Daniel [Cornell U., LNS; Tadel, Matevž [UC, San Diego; Wittich, Peter [Cornell U.; Würthwein, Frank [UC, San Diego; Yagil, Avi [UC, San Diego

    2017-01-01

    For over a decade now, physical and energy constraints have limited clock speed improvements in commodity microprocessors. Instead, chipmakers have been pushed into producing lower-power, multi-core processors such as Graphical Processing Units (GPU), ARM CPUs, and Intel MICs. Broad-based efforts from manufacturers and developers have been devoted to making these processors user-friendly enough to perform general computations. However, extracting performance from a larger number of cores, as well as specialized vector or SIMD units, requires special care in algorithm design and code optimization. One of the most computationally challenging problems in high-energy particle experiments is finding and fitting the charged-particle tracks during event reconstruction. This is expected to become by far the dominant problem at the High-Luminosity Large Hadron Collider (HL-LHC), for example. Today the most common track finding methods are those based on the Kalman filter. Experience with Kalman techniques on real tracking detector systems has shown that they are robust and provide high physics performance. This is why they are currently in use at the LHC, both in the trigger and offine. Previously we reported on the significant parallel speedups that resulted from our investigations to adapt Kalman filters to track fitting and track building on Intel Xeon and Xeon Phi. Here, we discuss our progresses toward the understanding of these processors and the new developments to port the Kalman filter to NVIDIA GPUs.

  11. Analysis of charged particle induced reactions for beam monitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Surendra Babu, K. [IOP, Academia Sinica, Taipe, Taiwan (China); Lee, Young-Ouk [Nuclear Data Evaluation Laboratory, Korea Atomic Energy Research Institute (Korea, Republic of); Mukherjee, S., E-mail: smukherjee_msuphy@yahoo.co.in [Department of Physics, Faculty of Science, M.S. University of Baroda, Vadodara 390 002 (India)

    2012-07-15

    The reaction cross sections for different residual nuclides produced in the charged particle (p, d, {sup 3}He and {alpha}) induced reactions were calculated and compared with the existing experimental data which are important for beam monitoring and medical diagnostic applications. A detailed literature compilation and comparison were made on the available data sets for the above reactions. These calculations were carried out using the statistical model code TALYS up to 100 MeV, which contains Kalbach's latest systematic for the emission of complex particles and complex particle-induced reactions. All optical model calculations were performed by ECIS-03, which is built into TALYS. The level density, optical model potential parameters were adjusted to get the better description of experimental data. Various pre-equilibrium models were used in the present calculations with default parameters.

  12. Online selection of short-lived particles on many-core computer architectures in the CBM experiment at FAIR

    Energy Technology Data Exchange (ETDEWEB)

    Zyzak, Maksym

    2016-07-07

    Modern experiments in heavy ion collisions operate with huge data rates that can not be fully stored on the currently available storage devices. Therefore the data flow should be reduced by selecting those collisions that potentially carry the information of the physics interest. The future CBM experiment will have no simple criteria for selecting such collisions and requires the full online reconstruction of the collision topology including reconstruction of short-lived particles. In this work the KF Particle Finder package for online reconstruction and selection of short-lived particles is proposed and developed. It reconstructs more than 70 decays, covering signals from all the physics cases of the CBM experiment: strange particles, strange resonances, hypernuclei, low mass vector mesons, charmonium, and open-charm particles. The package is based on the Kalman filter method providing a full set of the particle parameters together with their errors including position, momentum, mass, energy, lifetime, etc. It shows a high quality of the reconstructed particles, high efficiencies, and high signal to background ratios. The KF Particle Finder is extremely fast for achieving the reconstruction speed of 1.5 ms per minimum-bias AuAu collision at 25 AGeV beam energy on single CPU core. It is fully vectorized and parallelized and shows a strong linear scalability on the many-core architectures of up to 80 cores. It also scales within the First Level Event Selection package on the many-core clusters up to 3200 cores. The developed KF Particle Finder package is a universal platform for short- lived particle reconstruction, physics analysis and online selection.

  13. Online selection of short-lived particles on many-core computer architectures in the CBM experiment at FAIR

    International Nuclear Information System (INIS)

    Zyzak, Maksym

    2016-01-01

    Modern experiments in heavy ion collisions operate with huge data rates that can not be fully stored on the currently available storage devices. Therefore the data flow should be reduced by selecting those collisions that potentially carry the information of the physics interest. The future CBM experiment will have no simple criteria for selecting such collisions and requires the full online reconstruction of the collision topology including reconstruction of short-lived particles. In this work the KF Particle Finder package for online reconstruction and selection of short-lived particles is proposed and developed. It reconstructs more than 70 decays, covering signals from all the physics cases of the CBM experiment: strange particles, strange resonances, hypernuclei, low mass vector mesons, charmonium, and open-charm particles. The package is based on the Kalman filter method providing a full set of the particle parameters together with their errors including position, momentum, mass, energy, lifetime, etc. It shows a high quality of the reconstructed particles, high efficiencies, and high signal to background ratios. The KF Particle Finder is extremely fast for achieving the reconstruction speed of 1.5 ms per minimum-bias AuAu collision at 25 AGeV beam energy on single CPU core. It is fully vectorized and parallelized and shows a strong linear scalability on the many-core architectures of up to 80 cores. It also scales within the First Level Event Selection package on the many-core clusters up to 3200 cores. The developed KF Particle Finder package is a universal platform for short- lived particle reconstruction, physics analysis and online selection.

  14. Microstructures and performance of CaO-based ceramic cores with different particle size distributions for investment casting

    Science.gov (United States)

    Zhou, P. P.; Wu, G. Q.; Tao, Y.; Cheng, X.; Zhao, J. Q.; Nan, H.

    2018-02-01

    A series of calcium-based ceramic cores for casting titanium alloy were prepared by mixing different amounts of coarse and fine powders through injection molding. The effects of particle size on the microstructures and properties of the ceramic cores were investigated using quantitative and statistical analysis methods. It is found that the shrinkage and room-temperature strength of the ceramic cores were enhanced as increasing the contents of fine particles. Moreover, the creep resistance of the ceramic cores increased initially and then decreased. The increase in the fine particle content of the cores reduced the number and mean diameter of pores after sintering. The grain boundary density decreased firstly and then increased. The flexural strength of the ceramic cores at room temperature decreased with increasing porosity of ceramic cores, whereas the creep resistance increased with decreasing grain boundary density. A core exhibiting the optimal property was obtained when mixing 65 wt% of coarse powders (75-150 μm) and 35 wt% of fine powders (25-48 μm).

  15. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

    2011-01-01

    We have studied sulfuric acid aerosol nucleation in an atmospheric pressure reaction chamber using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear contribution from ion-induced nucleation and consider this to be the first unambiguous observation of the ion......-effect on aerosol nucleation using a particle beam under conditions that resemble the Earth's atmosphere. By comparison with ionization using a gamma source we further show that the nature of the ionizing particles is not important for the ion-induced component of the nucleation. This implies that inexpensive...... ionization sources - as opposed to expensive accelerator beams - can be used for investigations of ion-induced nucleation....

  16. Relationship between polycyclic aromatic hydrocarbons (PAHs) and particle size in dated core sediments in Lake Lianhuan, Northeast China

    International Nuclear Information System (INIS)

    Sun, Li; Zang, Shuying

    2013-01-01

    Atmospheric particle associated with pyrogenic polycyclic aromatic hydrocarbons (PAHs) poses serious threats to human health by inhalation exposure, especially in semiarid areas. Hence, the distributions of PAHs and particle size in two core sediments collected from Lake Lianhuan, Northeast China were studied. The sediments were dated radiometrically, and particle size distribution and PAH concentration were evaluated and potential human health risk was assessed. From 1980 to 2007, the dominant PAHs in the two cores were 2- and 3-ring PAHs, and the concentrations of 3–6 ring PAHs gradually increased from the early 1990s. Diagnostic ratios indicated that pyrogenic PAHs were the main sources of PAHs which changed over time from combustions of wood and coal to liquid fossil fuel sources. Fine particles ( 125 μm were found. Future research should focus on the seven carcinogenic pyrogenic PAHs due to a rapidly increasing trend since 1995 based on the assessment of toxic equivalency factors. - Highlights: • PAHs and particle size in core sediments were used to evaluate the role of eolian particles in delivering pyrogenic PAHs. • Changes of PAH sources closely followed local historical socioeconomic development since 1980s. • Changes of particulate sources from eolian to lacustrine reflected the evolving history of the lake. • Significant correlations between pyrogenic PAHs and eolian particles indicated potential risk from inhalation exposure. • Petroleum source PAHs are likely to stick to coarse particles and accumulate in lake sediments by surface runoff

  17. A facility for low energy charged particle induced reaction studies

    International Nuclear Information System (INIS)

    Vilaithong, T.; Singkarat, S.; Yu, L.D.; Intarasiri, S.; Tippawan, U.

    2000-01-01

    In Chiang Mai, a highly stable low energy ion accelerator (0 - 350 kV) facility is being established. A subnano-second pulsing system will be incorporated into the beam transport line. The detecting system will consist of a time-of-flight charged particle spectrometer and a high resolution gamma-ray system. The new facility will be used in the studies of low energy heavy ion backscattering and charged particle induced cross section measurement in the interests of material characterization and nucleosynthesis. (author)

  18. Controllable dielectric and electrical performance of polymer composites with novel core/shell-structured conductive particles through biomimetic method

    International Nuclear Information System (INIS)

    Yang, Dan; Tian, Ming; Wang, Wencai; Li, Dongdong; Li, Runyuan; Liu, Haoliang; Zhang, Liqun

    2013-01-01

    Highlights: ► Conductive core/shell-structured particles were synthesized by biomimetic method. ► These particles with silica/poly(dopamine)/silver core and poly(dopamine) shell. ► Dielectric composites were prepared with resulted particles and silicone elastomer. ► The dielectric properties of the composites can be controlled by shell thickness. ► This biomimetic method is simple, nontoxic, efficient and easy to control. - Abstract: Novel silica/poly(dopamine)/silver (from inner to outer) (denoted as SiO 2 /PDA/Ag) conductive micro-particles were first synthesized by biomimetic poly(dopamine) coating. These micro-particles were then coated with a poly(dopamine) layer to form core/shell-structured particles, with silica/poly(dopamine)/silver core and poly(dopamine) shell (denoted as SiO 2 /PDA/Ag/PDA). This multilayer core/shell micro-particles were confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscope. Polymer composites were then prepared by mechanical blending of poly(dimethyl siloxane) and the core/shell-structured particles. It was found that the silver layer and the poly(dopamine) shell had good adhesion with substrate and they kept intact even under violent shearing stress during mechanical mixing. The effect of the thickness of outermost poly(dopamine) shell as well as the loading amount of this filler on the dielectric and electrical properties of the composites was further studied. The results showed that the dielectric constant, dielectric loss, and conductivity of the composites decreased with increasing shell thickness (10–53 nm) at the same loading level. And the maximal dielectric constant of composites was achieved in the composites filled with SiO 2 /PDA/Ag/PDA (with 10–15 nm PDA shell) particles, which was much larger than that of the composite filled with SiO 2 /PDA/Ag particles without insulative PDA shell. At the same time, the composites can change

  19. A reduced scale two loop PWR core designed with particle swarm optimization technique

    International Nuclear Information System (INIS)

    Lima Junior, Carlos A. Souza; Pereira, Claudio M.N.A; Lapa, Celso M.F.; Cunha, Joao J.; Alvim, Antonio C.M.

    2007-01-01

    Reduced scale experiments are often employed in engineering projects because they are much cheaper than real scale testing. Unfortunately, designing reduced scale thermal-hydraulic circuit or equipment, with the capability of reproducing, both accurately and simultaneously, all physical phenomena that occur in real scale and at operating conditions, is a difficult task. To solve this problem, advanced optimization techniques, such as Genetic Algorithms, have been applied. Following this research line, we have performed investigations, using the Particle Swarm Optimization (PSO) Technique, to design a reduced scale two loop Pressurized Water Reactor (PWR) core, considering 100% of nominal power and non accidental operating conditions. Obtained results show that the proposed methodology is a promising approach for forced flow reduced scale experiments. (author)

  20. Meaningful timescales from Monte Carlo simulations of particle systems with hard-core interactions

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Liborio I., E-mail: liborio78@gmail.com

    2016-12-01

    A new Markov Chain Monte Carlo method for simulating the dynamics of particle systems characterized by hard-core interactions is introduced. In contrast to traditional Kinetic Monte Carlo approaches, where the state of the system is associated with minima in the energy landscape, in the proposed method, the state of the system is associated with the set of paths traveled by the atoms and the transition probabilities for an atom to be displaced are proportional to the corresponding velocities. In this way, the number of possible state-to-state transitions is reduced to a discrete set, and a direct link between the Monte Carlo time step and true physical time is naturally established. The resulting rejection-free algorithm is validated against event-driven molecular dynamics: the equilibrium and non-equilibrium dynamics of hard disks converge to the exact results with decreasing displacement size.

  1. The H1 linker histones: multifunctional proteins beyond the nucleosomal core particle.

    Science.gov (United States)

    Hergeth, Sonja P; Schneider, Robert

    2015-11-01

    The linker histone H1 family members are a key component of chromatin and bind to the nucleosomal core particle around the DNA entry and exit sites. H1 can stabilize both nucleosome structure and higher-order chromatin architecture. In general, H1 molecules consist of a central globular domain with more flexible tail regions at both their N- and C-terminal ends. The existence of multiple H1 subtypes and a large variety of posttranslational modifications brings about a considerable degree of complexity and makes studying this protein family challenging. Here, we review recent progress in understanding the function of linker histones and their subtypes beyond their role as merely structural chromatin components. We summarize current findings on the role of H1 in heterochromatin formation, transcriptional regulation and embryogenesis with a focus on H1 subtypes and their specific modifications. © 2015 The Authors.

  2. Diffusion-limited reactions of hard-core particles in one dimension

    Science.gov (United States)

    Bares, P.-A.; Mobilia, M.

    1999-02-01

    We investigate three different methods to tackle the problem of diffusion-limited reactions (annihilation) of hard-core classical particles in one dimension. We first extend an approach devised by Lushnikov [Sov. Phys. JETP 64, 811 (1986)] and calculate for a single species the asymptotic long-time and/or large-distance behavior of the two-point correlation function. Based on a work by Grynberg and Stinchcombe [Phys. Rev. E 50, 957 (1994); Phys. Rev. Lett. 74, 1242 (1995); 76, 851 (1996)], which was developed to treat stochastic adsorption-desorption models, we provide in a second step the exact two-point (one- and two-time) correlation functions of Lushnikov's model. We then propose a formulation of the problem in terms of path integrals for pseudo- fermions. This formalism can be used to advantage in the multispecies case, especially when applying perturbative renormalization group techniques.

  3. Vortex-Breakdown-Induced Particle Capture in Branching Junctions.

    Science.gov (United States)

    Ault, Jesse T; Fani, Andrea; Chen, Kevin K; Shin, Sangwoo; Gallaire, François; Stone, Howard A

    2016-08-19

    We show experimentally that a flow-induced, Reynolds number-dependent particle-capture mechanism in branching junctions can be enhanced or eliminated by varying the junction angle. In addition, numerical simulations are used to show that the features responsible for this capture have the signatures of classical vortex breakdown, including an approach flow aligned with the vortex axis and a pocket of subcriticality. We show how these recirculation regions originate and evolve and suggest a physical mechanism for their formation. Furthermore, comparing experiments and numerical simulations, the presence of vortex breakdown is found to be an excellent predictor of particle capture. These results inform the design of systems in which suspended particle accumulation can be eliminated or maximized.

  4. Nuclear reactions induced by high-energy alpha particles

    Science.gov (United States)

    Shen, B. S. P.

    1974-01-01

    Experimental and theoretical studies of nuclear reactions induced by high energy protons and heavier ions are included. Fundamental data needed in the shielding, dosimetry, and radiobiology of high energy particles produced by accelerators were generated, along with data on cosmic ray interaction with matter. The mechanism of high energy nucleon-nucleus reactions is also examined, especially for light target nuclei of mass number comparable to that of biological tissue.

  5. Alpha particle induced soft errors in NMOS RAMs: a review

    International Nuclear Information System (INIS)

    Carter, P.M.; Wilkins, B.R.

    1987-01-01

    The paper aims to explain the alpha particle induced soft error phenomenon using the NMOS dynamic random access memory (RAM) as a model. It discusses some of the many techniques experimented with by manufacturers to overcome the problem, and gives a review of the literature covering most aspects of soft errors in dynamic RAMs. Finally, the soft error performance of current dynamic RAM and static RAM products from several manufacturers are compared. (author)

  6. Neutron-Induced Charged Particle Studies at LANSCE

    Science.gov (United States)

    Lee, Hye Young; Haight, Robert C.

    2014-09-01

    Direct measurements on neutron-induced charged particle reactions are of interest for nuclear astrophysics and applied nuclear energy. LANSCE (Los Alamos Neutron Science Center) produces neutrons in energy of thermal to several hundreds MeV. There has been an effort at LANSCE to upgrade neutron-induced charged particle detection technique, which follows on (n,z) measurements made previously here and will have improved capabilities including larger solid angles, higher efficiency, and better signal to background ratios. For studying cross sections of low-energy neutron induced alpha reactions, Frisch-gridded ionization chamber is designed with segmented anodes for improving signal-to-noise ratio near reaction thresholds. Since double-differential cross sections on (n,p) and (n,a) reactions up to tens of MeV provide important information on deducing nuclear level density, the ionization chamber will be coupled with silicon strip detectors (DSSD) in order to stop energetic charged particles. In this paper, we will present the status of this development including the progress on detector design, calibrations and Monte Carlo simulations. This work is funded by the US Department of Energy - Los Alamos National Security, LLC under Contract DE-AC52-06NA25396.

  7. Investigation of energetic particle induced geodesic acoustic mode

    Science.gov (United States)

    Schneller, Mirjam; Fu, Guoyong; Chavdarovski, Ilija; Wang, Weixing; Lauber, Philipp; Lu, Zhixin

    2017-10-01

    Energetic particles are ubiquitous in present and future tokamaks due to heating systems and fusion reactions. Anisotropy in the distribution function of the energetic particle population is able to excite oscillations from the continuous spectrum of geodesic acoustic modes (GAMs), which cannot be driven by plasma pressure gradients due to their toroidally and nearly poloidally symmetric structures. These oscillations are known as energetic particle-induced geodesic acoustic modes (EGAMs) [G.Y. Fu'08] and have been observed in recent experiments [R. Nazikian'08]. EGAMs are particularly attractive in the framework of turbulence regulation, since they lead to an oscillatory radial electric shear which can potentially saturate the turbulence. For the presented work, the nonlinear gyrokinetic, electrostatic, particle-in-cell code GTS [W.X. Wang'06] has been extended to include an energetic particle population following either bump-on-tail Maxwellian or slowing-down [Stix'76] distribution function. With this new tool, we study growth rate, frequency and mode structure of the EGAM in an ASDEX Upgrade-like scenario. A detailed understanding of EGAM excitation reveals essential for future studies of EGAM interaction with micro-turbulence. Funded by the Max Planck Princeton Research Center. Computational resources of MPCDF and NERSC are greatefully acknowledged.

  8. Construction and immunological evaluation of truncated hepatitis B core particles carrying HBsAg amino acids 119–152 in the major immunodominant region (MIR)

    Energy Technology Data Exchange (ETDEWEB)

    Su, Qiudong; Yi, Yao [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing 102206 (China); Guo, Minzhuo [Beijing Entry-Exit Inspection and Quarantine Beureau, Tianshuiyuan Lane 6, Chaoyang District, Beijing 100026 (China); Qiu, Feng; Jia, Zhiyuan; Lu, Xuexin; Meng, Qingling [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing 102206 (China); Bi, Shengli, E-mail: shengli_bi@163.com [National Institute for Viral Disease Control and Prevention, China Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing 102206 (China)

    2013-09-13

    Highlights: •The conformational HBV neutralization antigen domain was successfully displayed on the surface of truncated HBc particles. •Appropriate dialysis procedures to support the renaturing environment for the protein refolding. •Efficient purification procedures to obtain high purity and icosahedral particles of mosaic HBV antigen. •Strong immune responses not only including neutralization antibody response but also Th1 cell response were induced in mice. -- Abstract: Hepatitis B capsid protein expressed in Escherichia coli can reassemble into icosahedral particles, which could strongly enhance the immunogenicity of foreign epitopes, especially those inserted into its major immunodominant region. Herein, we inserted the entire ‘α’ antigenic determinant amino acids (aa) 119–152 of HBsAg into the truncated HBc (aa 1–144), between Asp{sup 78} and Pro{sup 79}. Prokaryotic expression showed that the mosaic HBc was mainly in the form of inclusion bodies. After denaturation with urea, it was dialyzed progressively for protein renaturation. We observed that before and after renaturation, mosaic HBc was antigenic as determined by HBsAg ELISA and a lot of viruslike particles were observed after renaturation. Thus, we further purified the mosaic viruslike particles by (NH{sub 4}){sub 2}SO{sub 4} precipitation, DEAE chromatography, and Sepharose 4FF chromatography. Negative staining electron microscopy demonstrated the morphology of the viruslike particles. Immunization of Balb/c mice with mosaic particles induced the production of anti-HBs antibody and Th1 cell immune response supported by ELISPOT and CD4/CD8 proportions assay. In conclusion, we constructed mosaic hepatitis core particles displaying the entire ‘α’ antigenic determinant on the surface and laid a foundation for researching therapeutic hepatits B vaccines.

  9. Activation cross-section data for -particle-induced nuclear reactions ...

    Indian Academy of Sciences (India)

    B M ALI

    2018-02-20

    particle-induced nuclear reactions on natural vanadium up to 20 MeV. It should be mentioned that this study represents a part of (a supplement) systematical study of charged particles-induced nuclear reactions. Earlier studies were.

  10. Dual neutral particle induced transmutation in CINDER2008

    Energy Technology Data Exchange (ETDEWEB)

    Martin, W.J., E-mail: wjmarti@sandia.gov [Sandia National Laboratories, Albuquerque, NM 87185 (United States); University of New Mexico, Albuquerque, NM 87131 (United States); Oliveira, C.R.E. de; Hecht, A.A. [University of New Mexico, Albuquerque, NM 87131 (United States)

    2014-12-11

    Although nuclear transmutation methods for fission have existed for decades, the focus has been on neutron-induced reactions. Recent novel concepts have sought to use both neutrons and photons for purposes such as active interrogation of cargo to detect the smuggling of highly enriched uranium, a concept that would require modeling the transmutation caused by both incident particles. As photonuclear transmutation has yet to be modeled alongside neutron-induced transmutation in a production code, new methods need to be developed. The CINDER2008 nuclear transmutation code from Los Alamos National Laboratory is extended from neutron applications to dual neutral particle applications, allowing both neutron- and photon-induced reactions for this modeling with a focus on fission. Following standard reaction modeling, the induced fission reaction is understood as a two-part reaction, with an entrance channel to the excited compound nucleus, and an exit channel from the excited compound nucleus to the fission fragmentation. Because photofission yield data—the exit channel from the compound nucleus—are sparse, neutron fission yield data are used in this work. With a different compound nucleus and excitation, the translation to the excited compound state is modified, as appropriate. A verification and validation of these methods and data has been performed. This has shown that the translation of neutron-induced fission product yield sets, and their use in photonuclear applications, is appropriate, and that the code has been extended correctly. - Highlights: • The CINDER2008 transmutation code was modified to include photon-induced transmutation tracking. • A photonuclear interaction library was created to allow CINDER2008 to track photonuclear interactions. • Photofission product yield data sets were created using fission physics similarities with neutron-induced fission.

  11. The influence of some factors on the electrical conductivity and particle size of core/shell polystyrene/polyaniline composites

    Directory of Open Access Journals (Sweden)

    GORDANA D. NESTOROVIC

    2005-11-01

    Full Text Available The electrically conductive, micron-sized, core/shell polystyrene (PS/polyaniline (PANI composite particles were synthesized by chemical oxidative polymerization of aniline in the presence of micron-sized PS particles in 1 M HCl. The conditions of the dispersion polymerization of styrene were optimized. The influence of the initiator type employed for the chemical oxidative polymerization of aniline and the aniline (ANI concentration on the PS/PANI particle size and size distribution and their conductivity was investigated. The obtained results show that the conductivity of the samples increased with increasing ANI concentration. The conductivity of the PS/PANI composite particles obtained with the highest ANI concentration was of the same order of magnitude as that for PANI powder. The particle size did not depend on the concentration of ANI, while the particle size distribution was narrower at higher concentrations of ANI.

  12. The effect of surface-bulk potential difference on the kinetics of intercalation in core-shell active cathode particles

    Science.gov (United States)

    Kazemiabnavi, Saeed; Malik, Rahul; Orvananos, Bernardo; Abdellahi, Aziz; Ceder, Gerbrand; Thornton, Katsuyo

    2018-04-01

    Surface modification of active cathode particles is commonly observed in battery research as either a surface phase evolving during the cycling process, or intentionally engineered to improve capacity retention, rate capability, and/or thermal stability of the cathode material. Here, a continuum-scale model is developed to simulate the galvanostatic charge/discharge of a cathode particle with core-shell heterostructure. The particle is assumed to be comprised of a core material encapsulated by a thin layer of a second phase that has a different open-circuit voltage. The effect of the potential difference between the surface and bulk phases (Ω) on the kinetics of lithium intercalation and the galvanostatic charge/discharge profiles is studied at different values of Ω, C-rates, and exchange current densities. The difference between the Li chemical potential in the surface and bulk phases of the cathode particle results in a concentration difference between these two phases. This leads to a charge/discharge asymmetry in the galvanostatic voltage profiles, causing a decrease in the accessible capacity of the particle. These effects are more significant at higher magnitudes of surface-bulk potential difference. The proposed model provides detailed insight into the kinetics and voltage behavior of the intercalation/de-intercalation processes in core-shell heterostructure cathode particles.

  13. Alpha Particles Induce Autophagy in Multiple Myeloma Cells.

    Science.gov (United States)

    Gorin, Jean-Baptiste; Gouard, Sébastien; Ménager, Jérémie; Morgenstern, Alfred; Bruchertseifer, Frank; Faivre-Chauvet, Alain; Guilloux, Yannick; Chérel, Michel; Davodeau, François; Gaschet, Joëlle

    2015-01-01

    Radiation emitted by the radionuclides in radioimmunotherapy (RIT) approaches induce direct killing of the targeted cells as well as indirect killing through the bystander effect. Our research group is dedicated to the development of α-RIT, i.e., RIT using α-particles especially for the treatment of multiple myeloma (MM). γ-irradiation and β-irradiation have been shown to trigger apoptosis in tumor cells. Cell death mode induced by (213)Bi α-irradiation appears more controversial. We therefore decided to investigate the effects of (213)Bi on MM cell radiobiology, notably cell death mechanisms as well as tumor cell immunogenicity after irradiation. Murine 5T33 and human LP-1 MM cell lines were used to study the effects of such α-particles. We first examined the effects of (213)Bi on proliferation rate, double-strand DNA breaks, cell cycle, and cell death. Then, we investigated autophagy after (213)Bi irradiation. Finally, a coculture of dendritic cells (DCs) with irradiated tumor cells or their culture media was performed to test whether it would induce DC activation. We showed that (213)Bi induces DNA double-strand breaks, cell cycle arrest, and autophagy in both cell lines, but we detected only slight levels of early apoptosis within the 120 h following irradiation in 5T33 and LP-1. Inhibition of autophagy prevented (213)Bi-induced inhibition of proliferation in LP-1 suggesting that this mechanism is involved in cell death after irradiation. We then assessed the immunogenicity of irradiated cells and found that irradiated LP-1 can activate DC through the secretion of soluble factor(s); however, no increase in membrane or extracellular expression of danger-associated molecular patterns was observed after irradiation. This study demonstrates that (213)Bi induces mainly necrosis in MM cells, low levels of apoptosis, and autophagy that might be involved in tumor cell death.

  14. Alpha-particles induce autophagy in multiple myeloma cells

    Directory of Open Access Journals (Sweden)

    Joelle Marcelle Gaschet

    2015-10-01

    Full Text Available Objectives: Radiations emitted by the radionuclides in radioimmunotherapy (RIT approaches induce direct killing of the targeted cells as well as indirect killing through bystander effect. Our research group is dedicated to the development of α-RIT, i.e RIT using α-particles especially for the treatment of multiple myeloma (MM. γ-irradiation and β-irradiation have been shown to trigger apoptosis in tumor cells. Cell death mode induced by 213Bi α-irradiation appears more controversial. We therefore decided to investigate the effects of 213Bi on MM cell radiobiology, notably cell death mechanisms as well as tumor cell immunogenicity after irradiation.Methods: Murine 5T33 and human LP-1 multiple myeloma (MM cell lines were used to study the effects of such α-particles. We first examined the effects of 213Bi on proliferation rate, double strand DNA breaks, cell cycle and cell death. Then, we investigated autophagy after 213Bi irradiation. Finally, a co-culture of dendritic cells (DC with irradiated tumour cells or their culture media was performed to test whether it would induce DC activation.Results: We showed that 213Bi induces DNA double strand breaks, cell cycle arrest and autophagy in both cell lines but we detected only slight levels of early apoptosis within the 120 hours following irradiation in 5T33 and LP-1. Inhibition of autophagy prevented 213Bi induced inhibition of proliferation in LP-1 suggesting that this mechanism is involved in cell death after irradiation. We then assessed the immunogenicity of irradiated cells and found that irradiated LP-1 can activate DC through the secretion of soluble factor(s, however no increase in membrane or extracellular expression of danger associated molecular patterns (DAMPs was observed after irradiation.Conclusion: This study demonstrates that 213Bi induces mainly necrosis in MM cells, low levels of apoptosis and also autophagy that might be involved in tumor cell death.

  15. Particle-induced pulmonary acute phase response may be the causal link between particle inhalation and cardiovascular disease

    DEFF Research Database (Denmark)

    Saber, Anne T.; Jacobsen, Nicklas R.; Jackson, Petra

    2014-01-01

    Inhalation of ambient and workplace particulate air pollution is associated with increased risk of cardiovascular disease. One proposed mechanism for this association is that pulmonary inflammation induces a hepatic acute phase response, which increases risk of cardiovascular disease. Induction...... epidemiological studies. In this review, we present and review emerging evidence that inhalation of particles (e.g., air diesel exhaust particles and nanoparticles) induces a pulmonary acute phase response, and propose that this induction constitutes the causal link between particle inhalation and risk...

  16. Induced anisotropy effect in nanocrystalline cores for GFCBs

    Energy Technology Data Exchange (ETDEWEB)

    Waeckerle, T. E-mail: thierry.waeckerle@imphy.usinor.com; Verin, Ph.; Cremer, P.; Gautard, D

    2000-06-02

    Nanocrystalline materials are very efficient for GFCB cores with flat hysteresis loop, especially if permeability may be raised in keeping low the remanent induction. This can be achieved with peculiar field annealing . A thermodynamic model is proposed to explain the experimental evidence.

  17. Synthesis of Cu/SiO2 Core-Shell Particles Using Hyperbranched Polyester as Template and Dispersant

    Science.gov (United States)

    Han, Wensong

    2017-07-01

    Third-generation hyperbranched polyester (HBPE3) was synthesized by stepwise polymerization with N, N-diethylol-3-amine methylpropionate as AB2 monomer and pentaerythritol as core molecule. Then, Cu particles were prepared by reduction of copper nitrate with ascorbic acid in aqueous solution using HBPE3 as template. Finally, Cu/SiO2 particles were prepared by coating silica on the surface of Cu particles. The structure and morphology of the samples were characterized by Fourier-transform infrared (FT-IR) spectrometry, x-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results confirmed the formation of the silica coating on the surface of Cu and that the Cu/SiO2 particles had spherical shape with particle size in the range of 0.8 μm to 2 μm. Compared with pure Cu, the synthesized Cu/SiO2 core-shell particles exhibited better oxidation resistance at high temperature. Moreover, the oxidation resistance of the Cu/SiO2 particles increased significantly with increasing tetraethyl orthosilicate (TEOS) concentration.

  18. Relationship between polycyclic aromatic hydrocarbons (PAHs) and particle size in dated core sediments in Lake Lianhuan, Northeast China

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Li; Zang, Shuying, E-mail: zsy6311@163.com

    2013-09-01

    Atmospheric particle associated with pyrogenic polycyclic aromatic hydrocarbons (PAHs) poses serious threats to human health by inhalation exposure, especially in semiarid areas. Hence, the distributions of PAHs and particle size in two core sediments collected from Lake Lianhuan, Northeast China were studied. The sediments were dated radiometrically, and particle size distribution and PAH concentration were evaluated and potential human health risk was assessed. From 1980 to 2007, the dominant PAHs in the two cores were 2- and 3-ring PAHs, and the concentrations of 3–6 ring PAHs gradually increased from the early 1990s. Diagnostic ratios indicated that pyrogenic PAHs were the main sources of PAHs which changed over time from combustions of wood and coal to liquid fossil fuel sources. Fine particles (< 65 μm) were the predominant particle size (56–97%). Lacustrine source (with the peak towards 200–400 μm) and eolian sources derived from short (2.0–10 and 30–65 μm) and long (0.4–1.0 μm) distance suspension were indentified from frequency distribution pattern of particle size. Significant correlations between 3–6 ring PAHs (especially carcinogenic 5–6 ring PAHs) and 10–35 μm particulate fractions indicated that eolian particles played an important role in adsorbing pyrogenic PAHs. Petroleum source of PAHs was only identified during the 1980s in one core sediments, in which positive correlations between 2-ring PAHs and particulate fractions of > 125 μm were found. Future research should focus on the seven carcinogenic pyrogenic PAHs due to a rapidly increasing trend since 1995 based on the assessment of toxic equivalency factors. - Highlights: • PAHs and particle size in core sediments were used to evaluate the role of eolian particles in delivering pyrogenic PAHs. • Changes of PAH sources closely followed local historical socioeconomic development since 1980s. • Changes of particulate sources from eolian to lacustrine reflected the

  19. Neutrino-induced nucleosynthesis in core-collapse supernovae

    International Nuclear Information System (INIS)

    Hartmann, D.H.; Haxton, W.C.; Hoffman, R.D.; Woosley, S.E.; California Univ., Santa Cruz, CA

    1990-01-01

    Almost all of the 3·10 53 ergs liberated in a core collapse supernova is radiated as neutrinos by the cooling neutron star. The neutrinos can excite nuclei in the mantle of the star by their neutral and charged current reactions. The resulting spallation reactions are an important nuleosynthesis mechanism that may be responsible for the galactic abundances of 7 Li, 11 B, 19 F, 138 La, 180 Ta, and number of other nuclei. 10 refs., 1 fig., 1 tab

  20. Parallelized Kalman-Filter-Based Reconstruction of Particle Tracks on Many-Core Architectures

    Energy Technology Data Exchange (ETDEWEB)

    Cerati, Giuseppe [Fermilab; Elmer, Peter [Princeton U.; Krutelyov, Slava [UC, San Diego; Lantz, Steven [Cornell U., Phys. Dept.; Lefebvre, Matthieu [Princeton U.; Masciovecchio, Mario [UC, San Diego; McDermott, Kevin [Cornell U., Phys. Dept.; Riley, Daniel [Cornell U., Phys. Dept.; Tadel, Matevž [UC, San Diego; Wittich, Peter [Cornell U., Phys. Dept.; Würthwein, Frank [UC, San Diego; Yagil, Avi [UC, San Diego

    2017-11-16

    Faced with physical and energy density limitations on clock speed, contemporary microprocessor designers have increasingly turned to on-chip parallelism for performance gains. Examples include the Intel Xeon Phi, GPGPUs, and similar technologies. Algorithms should accordingly be designed with ample amounts of fine-grained parallelism if they are to realize the full performance of the hardware. This requirement can be challenging for algorithms that are naturally expressed as a sequence of small-matrix operations, such as the Kalman filter methods widely in use in high-energy physics experiments. In the High-Luminosity Large Hadron Collider (HL-LHC), for example, one of the dominant computational problems is expected to be finding and fitting charged-particle tracks during event reconstruction; today, the most common track-finding methods are those based on the Kalman filter. Experience at the LHC, both in the trigger and offline, has shown that these methods are robust and provide high physics performance. Previously we reported the significant parallel speedups that resulted from our efforts to adapt Kalman-filter-based tracking to many-core architectures such as Intel Xeon Phi. Here we report on how effectively those techniques can be applied to more realistic detector configurations and event complexity.

  1. Fabrication and characterization of flaky core-shell particles by magnetron sputtering silver onto diatomite

    Science.gov (United States)

    Wang, Yuanyuan; Zhang, Deyuan; Cai, Jun

    2016-02-01

    Diatomite has delicate porous structures and various shapes, making them ideal templates for microscopic core-shell particles fabrication. In this study, a new process of magnetron sputtering assisted with photoresist positioning was proposed to fabricate lightweight silver coated porous diatomite with superior coating quality and performance. The diatomite has been treated with different sputtering time to investigate the silver film growing process on the surface. The morphologies, constituents, phase structures and surface roughness of the silver coated diatomite were analyzed with SEM, EDS, XRD and AFM respectively. The results showed that the optimized magnetron sputtering time was 8-16 min, under which the diatomite templates were successfully coated with uniform silver film, which exhibits face centered cubic (fcc) structure, and the initial porous structures were kept. Moreover, this silver coating has lower surface roughness (RMS 4.513 ± 0.2 nm) than that obtained by electroless plating (RMS 15.692 ± 0.5 nm). And the infrared emissivity of coatings made with magnetron sputtering and electroless plating silver coated diatomite can reach to the lowest value of 0.528 and 0.716 respectively.

  2. Charged particle induced energy dispersive X-ray analysis

    International Nuclear Information System (INIS)

    Johansson, S.A.E.

    1979-01-01

    This review article deals with the X-ray emission induced by heavy, charged particles and the use of this process as an analytical method (PIXE). The physical processes involved, X-ray emission and the various reactions contributing to the background, are described in some detail. The sensitivity is calculated theoretically and the results compared with practical experience. A discussion is given on how the sensitivity can be optimized. The experimental arrangements are described and the various technical problems discussed. The analytical procedure, especially the sample preparation, is described in considerable detail. A number of typical practical applications are discussed. (author)

  3. Radiation-induced preparation of core/shell gold/albumin nanoparticles

    Science.gov (United States)

    Flores, Constanza Y.; Achilli, Estefania; Grasselli, Mariano

    2018-01-01

    Nanoparticles (NPs) are one of the most promising nanomaterials to be used in the biomedical field. Gold NPs (Au-NPs) have been covered with monolayers of many different molecules and macromolecules to prepare different kinds of biosensors. However, these coatings based on physisorption methods are not stable enough to prepare functional nanomaterials to be used in complex mixtures or in vivo applications. The aim of this work was to prepare a protein coating of Au-NPs based on a protein multilayer covering, stabilized by a novel radiation-induced crosslinking process. Albumins from human and bovine source were added to Au-NPs suspension and followed by ethanol addition to induce protein aggregation. Samples were irradiated with a gamma source at 10 kGy to induce a protein crosslinking according to recent findings. Samples containing 30%v/v ethanol showed a plasmon peak at about 532 nm, demonstrating the presence of non-aggregated Au-NPs. Using higher ethanol concentrations, the absorbance of plasmon peak showed NP aggregation. By Dynamic Light Scattering measurements, a new particle population with an average diameter of about 60 nm was found. Moreover, TEM images showed that the NPs had spherical shape and the presence of a low-density halo around the metal core confirmed the presence of the protein shell. An irradiation dose of one kGy was enough to show changes in the plasmon peak characteristics. The increase in the chemical stability of protein shell was demonstrated by the reduction in the NP dissolution kinetics in presence of cyanate.

  4. Fission product retention in TRISO coated UO2 particle fuels subjected to HTR simulated core heating tests

    International Nuclear Information System (INIS)

    Baldwin, C.A.; Kania, M.J.

    1991-01-01

    Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbounded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600 deg. C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800 deg. C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800 deg. C and above may exist. (author). 6 refs, 6 figs, 4 tabs

  5. Fission product retention in TRISCO coated UO2 particle fuels subjected to HTR simulated core heating tests

    International Nuclear Information System (INIS)

    Baldwin, C.A.; Kania, M.J.

    1990-11-01

    Results of the examination and analysis of 25,730 individual microspheres from spherical fuel elements HFR-K3/1 and HFR-K3/3 are reported. The parent spheres were irradiated in excess of end-of-life exposure and subsequently subjected to simulated core heating tests in a special high-temperature furnace at Forschungszentrum, Juelich, GmbH (KFA). Following the heating tests, the spheres were electrolytically deconsolidated to obtain unbonded fuel particles for Irradiated Microsphere Gamma Analyzer (IMGA) analysis. For sphere HFR-K3/1, which was heated for 500 h at 1600 degree C, only four particles were identified as having released fission products. The remaining particles from the sphere showed no statistical evidence of fission product release. Scanning Electron Microscopy (SEM) examination showed that three of the defect particles had large sections of the TRISO coating missing, while the fourth appeared normal. For sphere HFR-K3/3, which was heated for 100 h at 1800 degree C, the IMGA data revealed that fission product release (cesium) from individual particles was significant and that there was large particle-to-particle variation in retention capabilities. Individual particle release (cesium) averaged ten times the KFA-measured integral spherical fuel element release value. In addition, the bimodal distribution of the individual particle data indicated that two distinct modes of failure at fuel temperatures of 1800 degree C and above may exist. 6 refs., 6 figs., 4 tabs

  6. Calculation of the ex-core neutron noise induced by fuel vibrations in PWRs

    International Nuclear Information System (INIS)

    Tran Hoai Nam; Cao Van Chung; Hoang Thanh Phi Hung; Hoang Van Khanh

    2015-01-01

    Calculation of the neutron noise induced by fuel assembly vibrations in two pressurized water reactor (PWR) cores has been performed to investigate the effect of cycle burnup on the properties of the ex-core detector noise. Pendular vibrations of individual fuel assemblies were assumed to occur at different locations in the core. The auto power spectra density (APSD) of the ex-core detector noise was evaluated with the assumption of stochastic vibrations along a random two-dimensional trajectory. The results show that no general monotonic variation of APSD was found. The increase of APSD occurs predominantly for peripheral assemblies. Assuming simultaneous vibrations of a number of fuel assemblies uniformly distributed over the core with the more realistic perturbation model, the effect of the peripheral assemblies will dominate and the increase of the amplitude of the ex-core neutron noise with burnup can be confirmed. (author)

  7. Corrosion-induced microstructural changes in a US core graphite

    International Nuclear Information System (INIS)

    Eatherly, W.P.; Lee, D.A.

    1981-01-01

    The results reported here apply to Great Lakes grade H-451 graphite, the core graphite specified for the US HTGR. This graphite is structurally similar to the German reflector grades we have investigated at ORNL, and hence should be applicable to them if similar impurity levels are obtained. Moreover, these results extend and confirm the behavior pattern exhibited by the fuel matrix material A3-3 reported in the previous paper, although the effects are more pronounced in A3-3 presumably due to its resin-type binder and low heat-treatment temperatures

  8. Shear-induced particle migration in suspensions of rods

    Energy Technology Data Exchange (ETDEWEB)

    Mondy, L.A. (Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)); Brenner, H. (Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)); Altobelli, S.A. (The Lovelace Institutes, 2425 Ridgecrest Drive, S. E., Albuquerque, New Mexico 87108 (United States)); Abbott, J.R.; Graham, A.L. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

    1994-03-01

    Shear-induced migration of particles occurs in suspensions of neutrally buoyant spheres in Newtonian fluids undergoing shear in the annular space between two rotating, coaxial cylinders (a wide-gap Couette), even when the suspension is in creeping flow. Previous studies have shown that the rate of migration of spherical particles from the high-shear-rate region near the inner (rotating) cylinder to the low-shear-rate region near the outer (stationary) cylinder increases rapidly with increasing sphere size. To determine the effect of particle shape, the migration of rods suspended in Newtonian fluids was recently measured. The behavior of several suspensions was studied. Each suspension contained well-characterized, uniform rods with aspect ratios ranging from 2 to 18 at either 0.30 or 0.40 volume fraction. At the same volume fraction of solids, the steady-state, radial concentration profiles for rods were independent of aspect ratio and were indistinguishable from those obtained from suspended spheres. Only minor differences near the walls (attributable to the finite size of the rods relative to the curvature of the walls) appeared to differentiate the profiles. Data taken during the transition from a well-mixed suspension to the final steady state show that the rate of migration increased as the volume of the individual rods increased.

  9. Report of the workshop on 'light particle-induced reactions'

    International Nuclear Information System (INIS)

    1992-01-01

    The study meeting on light particle (mass number = 3 - 11)-induced reation was held for three days from December 5 to 7, 1991 at the Research Center for Nuclear Physics, Osaka University. This book records the report based on the lectures presented at the meeting. In the new facility of the RCNP, the experiment on the nuclear reaction using 400 MeV polarized protons and 200 MeV polarized deuterons is about to begin. When the acceleration of polarized He-3 beam which is being developed at present becomes feasible, by combining it with the high resolution spectrometer GRAND RAIDEN, it is expected that the unique, high accuracy research using the polarized He-3 having intermediate energy (540 MeV) becomes possible. At this time, by focusing attention to what new physics is developed by the nuclear reaction induced by the composite particles having the intermediate energy of mass number 3 - 11, this study meeting was planned and held. As the results, 29 lectures collected in this book were to cover wide fields, and active discussion was carried out. (K.I.)

  10. Applications of particle induced X-ray emission

    International Nuclear Information System (INIS)

    Akselsson, K. R.

    1978-01-01

    In Particle Induced X-ray Emission (PIXE) analysis samples are bombarded by protons or α-particles of a few MeV/u. The induced characteristic x-rays are detected with a x-ray detector e.g. a Si(Li)-detector. The energies of the x-ray peaks are characteristic for the elements in the samples and the intensities of the x-ray transitions are proportional to the abundances of the elements. The research area which first attracted those of us working with PIXE was the study of sources, transport and deposition of airborne particulates. Sources, transport, wet deposition, other applications where PIXE is already known to be competitive are trace elemental analysis of water below the ppb-level and analyses requiring a space resolution of 1-10μ. However, there is still much to do for physicists in developing the full potential of low-energy accelerators as analytical tools in multidisciplinary teams. (JIW)

  11. Fireworks induced particle pollution: A spatio-temporal analysis

    Science.gov (United States)

    Kumar, M.; Singh, R. K.; Murari, V.; Singh, A. K.; Singh, R. S.; Banerjee, T.

    2016-11-01

    Diwali-specific firework induced particle pollution was measured in terms of aerosol mass loading, type, optical properties and vertical distribution. Entire nation exhibited an increase in particulate concentrations specifically in Indo-Gangetic Plain (IGP). Aerosol surface mass loading at middle IGP revealed an increase of 56-121% during festival days in comparison to their background concentrations. Space-borne measurements (Aqua and Terra-MODIS) typically identified IGP with moderate to high AOD (0.3-0.8) during pre-festive days which transmutes to very high AOD (0.4-1.8) during Diwali-day with accumulation of aerosol fine mode fractions (0.3-1.0). Most of the aerosol surface monitoring stations exhibited increase in PM2.5 especially on Diwali-day while PM10 exhibited increase on subsequent days. Elemental compositions strongly support K, Ba, Sr, Cd, S and P to be considered as firework tracers. The upper and middle IGP revealed dominance of absorbing aerosols (OMI-AI: 0.80-1.40) while CALIPSO altitude-orbit-cross-section profiles established the presence of polluted dust which eventually modified with association of smoke and polluted continental during extreme fireworks. Diwali-specific these observations have implications on associating fireworks induced particle pollution and human health while inclusion of these observations should improve regional air quality model.

  12. New long-cycle small modular PWR cores using particle type burnable poisons for low boron operation

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hoseong; Hwang, Dae Hee [Department of Nuclear Engineering, Kyung Hee University, Deogyeong-daero, GiHeung-gu, Yongin, Gyeonggi-do 446-701 (Korea, Republic of); Hong, Ser Gi, E-mail: sergihong@khu.ac.kr [Department of Nuclear Engineering, Kyung Hee University, Deogyeong-daero, GiHeung-gu, Yongin, Gyeonggi-do 446-701 (Korea, Republic of); Shin, Ho Choel [Core and Fuel Analysis Group, Korea Hydro & Nuclear Power Central Research Institute (KHNP-CRI), Daejon 305-343 (Korea, Republic of)

    2017-04-01

    Highlights: • New advanced burnable poison rods (BPR) are suggested for low boron operation in PWR. • The new SMR cores have long cycle length of ∼4.5 EFPYs with low boron concentration. • The SMR core satisfies all the design targets and constraints. - Abstract: In this paper, new small long-cycle PWR (Pressurized Water Reactor) cores for low boron concentration operation are designed by employing advanced burnable poison rods (BPRs) in which the BISO (Bi-Isotropic) particles of burnable poison are distributed in a SiC matrix. The BPRs are designed by adjusting the kernel diameter, the kernel material and the packing fraction to effectively reduce the excess reactivity in order to reduce the boron concentration in the coolant and achieve a flat change in excess reactivity over a long operational cycle. In addition, axial zoning of the BPRs was suggested to improve the core performances, and it was shown that the suggested axial zoning of BPRs considerably extends the cycle length compared to a core with no BPR axial zoning. The results of the core physics analyses showed that the cores using BPRs with a B{sub 4}C kernel have long cycle lengths of ∼4.5 EFPYs (Effective Full Power Years), small maximum CBCs (Critical Boron Concentration) lower than 370 ppm, low power peaking factors, and large shutdown margins of control element assemblies.

  13. Quantum behaved Particle Swarm Optimization with Differential Mutation operator applied to WWER-1000 in-core fuel management optimization

    International Nuclear Information System (INIS)

    Jamalipour, Mostafa; Sayareh, Reza; Gharib, Morteza; Khoshahval, Farrokh; Karimi, Mahmood Reza

    2013-01-01

    Highlights: ► A new method called QPSO-DM is applied to BNPP in-core fuel management optimization. ► It is found that QPSO-DM performs better than PSO and QPSO. ► This method provides a permissible arrangement for optimum loading pattern. - Abstract: This paper presents a new method using Quantum Particle Swarm Optimization with Differential Mutation operator (QPSO-DM) for optimizing WWER-1000 core fuel management. Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) have shown good performance on in-core fuel management optimization (ICFMO). The objective of this paper is to show that QPSO-DM performs very well and is comparable to PSO and Quantum Particle Swarm Optimization (QPSO). Most of the strategies for ICFMO are based on maximizing multiplication factor (k eff ) to increase cycle length and minimizing power peaking factor (P q ) in order to improve fuel integrity. PSO, QPSO and QPSO-DM have been implemented to fulfill these requirements for the first operating cycle of WWER-1000 Bushehr Nuclear Power Plant (BNPP). The results show that QPSO-DM performs better than the others. A program has been written in MATLAB to map PSO, QPSO and QPSO-DM for loading pattern optimization. WIMS and CITATION have been used to simulate reactor core for neutronic calculations

  14. Alpha particles induce expression of immunogenic markers on tumour cells

    International Nuclear Information System (INIS)

    Gorin, J.B.; Gouard, S.; Cherel, M.; Davodeau, F.; Gaschet, J.; Morgenstern, A.; Bruchertseifer, F.

    2013-01-01

    The full text of the publication follows. Radioimmunotherapy (RIT) is an approach aiming at targeting the radioelements to tumours, usually through the use of antibodies specific for tumour antigens. The radiations emitted by the radioelements then induce direct killing of the targeted cells as well as indirect killing through bystander effect. Interestingly, it has been shown that ionizing radiations, in some settings of external radiotherapy, can foster an immune response directed against tumour cells. Our research team is dedicated to the development of alpha RIT, i.e RIT using alpha particle emitters, we therefore decided to study the effects of such particles on tumour cells in regards to their immunogenicity. First, we studied the effects of bismuth 213, an alpha emitter, on cellular death and autophagy in six different tumour cell lines. Then, we measured the expression of 'danger' signals and MHC molecules at the cell surface to determine whether irradiation with 213 Bi could cause the tumour cells to be recognized by the immune system. Finally a co-culture of dendritic cells with irradiated tumour cells was performed to test whether it would induce dendritic cells to mature. No apoptosis was detected within 48 hours after irradiation in any cell line, however half of them exhibited signs of autophagy. No increase in membrane expression of 'danger' signals was observed after treatment with 213 Bi, but we showed an increase in expression of MHC class I and II for some cell lines. Moreover, the co-culture experiment indicated that the immunogenicity of a human adenocarcinoma cell line (LS 174T) was enhanced in vitro after irradiation with alpha rays. These preliminary data suggest that alpha particles could be of interest in raising an immune response associated to RIT. (authors)

  15. Particle transport model sensitivity on wave-induced processes

    Science.gov (United States)

    Staneva, Joanna; Ricker, Marcel; Krüger, Oliver; Breivik, Oyvind; Stanev, Emil; Schrum, Corinna

    2017-04-01

    Different effects of wind waves on the hydrodynamics in the North Sea are investigated using a coupled wave (WAM) and circulation (NEMO) model system. The terms accounting for the wave-current interaction are: the Stokes-Coriolis force, the sea-state dependent momentum and energy flux. The role of the different Stokes drift parameterizations is investigated using a particle-drift model. Those particles can be considered as simple representations of either oil fractions, or fish larvae. In the ocean circulation models the momentum flux from the atmosphere, which is related to the wind speed, is passed directly to the ocean and this is controlled by the drag coefficient. However, in the real ocean, the waves play also the role of a reservoir for momentum and energy because different amounts of the momentum flux from the atmosphere is taken up by the waves. In the coupled model system the momentum transferred into the ocean model is estimated as the fraction of the total flux that goes directly to the currents plus the momentum lost from wave dissipation. Additionally, we demonstrate that the wave-induced Stokes-Coriolis force leads to a deflection of the current. During the extreme events the Stokes velocity is comparable in magnitude to the current velocity. The resulting wave-induced drift is crucial for the transport of particles in the upper ocean. The performed sensitivity analyses demonstrate that the model skill depends on the chosen processes. The results are validated using surface drifters, ADCP, HF radar data and other in-situ measurements in different regions of the North Sea with a focus on the coastal areas. The using of a coupled model system reveals that the newly introduced wave effects are important for the drift-model performance, especially during extremes. Those effects cannot be neglected by search and rescue, oil-spill, transport of biological material, or larva drift modelling.

  16. Subway particles are more genotoxic than street particles and induce oxidative stress in cultured human lung cells.

    Science.gov (United States)

    Karlsson, Hanna L; Nilsson, Lennart; Möller, Lennart

    2005-01-01

    Epidemiological studies have shown an association between airborne particles and a wide range of adverse health effects. The mechanisms behind these effects include oxidative stress and inflammation. Even though traffic gives rise to high levels of particles in the urban air, people are exposed to even higher levels in the subway. However, there is a lack of knowledge regarding how particles from different urban subenvironments differ in toxicity. The main aim of the present study was to compare the ability of particles from a subway station and a nearby very busy urban street, respectively, to damage DNA and to induce oxidative stress. Cultured human lung cells (A549) were exposed to particles, DNA damage was analyzed using single cell gel electrophoresis (the comet assay), and the ability to induce oxidative stress was measured as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) formation in lung cell DNA. We found that the subway particles were approximately eight times more genotoxic and four times more likely to cause oxidative stress in the lung cells. When the particles, water extracts from the particles, or particles treated with the metal chelator deferoxamine mesylate were incubated with 2'-deoxyguanosine (dG) and 8-oxodG was analyzed, we found that the oxidative capacity of the subway particles was due to redox active solid metals. Furthermore, analysis of the atomic composition showed that the subway particles to a dominating degree (atomic %) consisted of iron, mainly in the form of magnetite (Fe3O4). By using electron microscopy, the interaction between the particles and the lung cells was shown. The in vitro reactivity of the subway particles in combination with the high particle levels in subway systems give cause of concern due to the high number of people that are exposed to subway particles on a daily basis. To what extent the subway particles cause health effects in humans needs to be further evaluated.

  17. HCV Core Protein Uses Multiple Mechanisms to Induce Oxidative Stress in Human Hepatoma Huh7 Cells

    Science.gov (United States)

    Ivanov, Alexander V.; Smirnova, Olga A.; Petrushanko, Irina Y.; Ivanova, Olga N.; Karpenko, Inna L.; Alekseeva, Ekaterina; Sominskaya, Irina; Makarov, Alexander A.; Bartosch, Birke; Kochetkov, Sergey N.; Isaguliants, Maria G.

    2015-01-01

    Hepatitis C virus (HCV) infection is accompanied by the induction of oxidative stress, mediated by several virus proteins, the most prominent being the nucleocapsid protein (HCV core). Here, using the truncated forms of HCV core, we have delineated several mechanisms by which it induces the oxidative stress. The N-terminal 36 amino acids of HCV core induced TGFβ1-dependent expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases 1 and 4, both of which independently contributed to the production of reactive oxygen species (ROS). The same fragment also induced the expression of cyclo-oxygenase 2, which, however, made no input into ROS production. Amino acids 37–191 of HCV core up-regulated the transcription of a ROS generating enzyme cytochrome P450 2E1. Furthermore, the same fragment induced the expression of endoplasmic reticulum oxidoreductin 1α. The latter triggered efflux of Ca2+ from ER to mitochondria via mitochondrial Ca2+ uniporter, leading to generation of superoxide anions, and possibly also H2O2. Suppression of any of these pathways in cells expressing the full-length core protein led to a partial inhibition of ROS production. Thus, HCV core causes oxidative stress via several independent pathways, each mediated by a distinct region of the protein. PMID:26035647

  18. Synthesis and characterization of magnetic and non-magnetic core-shell polyepoxide micrometer-sized particles of narrow size distribution.

    Science.gov (United States)

    Omer-Mizrahi, Melany; Margel, Shlomo

    2009-01-15

    Core polystyrene microspheres of narrow size distribution were prepared by dispersion polymerization of styrene in a mixture of ethanol and 2-methoxy ethanol. Uniform polyglycidyl methacrylate/polystyrene core-shell micrometer-sized particles were prepared by emulsion polymerization at 73 degrees C of glycidyl methacrylate in the presence of the core polystyrene microspheres. Core-shell particles with different properties (size, surface morphology and composition) have been prepared by changing various parameters belonging to the above seeded emulsion polymerization process, e.g., volumes of the monomer glycidyl methacrylate and the crosslinker monomer ethylene glycol dimethacrylate. Magnetic Fe(3)O(4)/polyglycidyl methacrylate/polystyrene micrometer-sized particles were prepared by coating the former core-shell particles with magnetite nanoparticles via a nucleation and growth mechanism. Characterization of the various particles has been accomplished by routine methods such as light microscopy, SEM, FTIR, BET and magnetic measurements.

  19. Study and analysis for the flow-induced vibration of the core barrel of a PWR

    International Nuclear Information System (INIS)

    Yao Weida; Shi Guolin; Jiang Nanyan

    1989-01-01

    The resemblance criteria are derived and a test model is designed by applying the flow-soild coupling theory. After having completed the model analysis of the pressurized water reactor (PWR) core barrel in an 1:10 model, the dynamic characteristics are obtained. In an 1:5 reactor model with a hydraulic closed loop, the hydraulic vibration tests of the core barrel are performed, and the relations between the flow rate and the flow-induced pulse pressure on core barrel, acceleration and strain signals have been measured. The corresponding responses and a group of computational equations for hydraulic vibration are derived from these two experiments. The computational hydraulic vibration responses for core barrel in Qinshan Nuclear Power Plant are in good agreement with the test results, and it shows that the core barrel is safe within its lifetime of 30 years

  20. Aerosol nucleation induced by a high energy particle beam

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker; Pedersen, Jens Olaf Pepke; Uggerhøj, Ulrik I.

    The effect of ions in aerosol nucleation is a subject where much remains to be discovered. That ions can enhance nucleation has been shown by theory, observations, and experiments. However, the exact mechanism still remains to be determined. One question is if the nature of the ionization affects...... the nucleation. This is an essential question since many experiments have been performed using radioactive sources that ionize differently than the cosmic rays which are responsible for the majority of atmospheric ionization. Here we report on an experimental study of sulphuric acid aerosol nucleation under near...... atmospheric conditions using a 580 MeV electron beam to ionize the volume of the reaction chamber. We find a clear and significant contribution from ion induced nucleation and consider this to be an unambiguous observation of the ion-effect on aerosol nucleation using a particle beam under conditions not far...

  1. Energetic particle induced desorption of water vapor cryo-condensate

    International Nuclear Information System (INIS)

    Menon, M.M.; Owen, L.W.; Simpkins, J.E.; Uckan, T.; Mioduszewski, P.K.

    1990-01-01

    An in-vessel cryo-condensation pump is being designed for the Advanced Divertor configuration of the DIII-D tokamak. To assess the importance of possible desorption of water vapor from the cryogenic surfaces of the pump due to impingement of energetic particles from the plasma, a 77 K surface on which a thin layer of water vapor was condensed was exposed to a tenuous plasma (density = 2 x 10 10 cm -3 , electron temperature = 3 eV). Significant desorption of the condensate occurred, suggesting that impingement of energeticparticles (10 eV) at flux levels of ∼10 16 cm 2 s -1 on cryogenic surfaces could potentially induce impurity problems in the tokamak plasma. A pumping configuration is presented in which this problem is minimized without sacrificing the pumping speed

  2. Thermodynamics of gravitationally induced particle creation scenario in DGP braneworld

    Energy Technology Data Exchange (ETDEWEB)

    Jawad, Abdul; Rani, Shamaila; Rafique, Salman [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan)

    2018-01-15

    In this paper, we discuss the thermodynamical analysis for gravitationally induced particle creation scenario in the framework of DGP braneworld model. For this purpose, we consider apparent horizon as the boundary of the universe. We take three types of entropy such as Bakenstein entropy, logarithmic corrected entropy and power law corrected entropy with ordinary creation rate Γ. We analyze the first law and generalized second law of thermodynamics analytically for these entropies which hold under some constraints. The behavior of total entropy in each case is also discussed which implies the validity of generalized second law of thermodynamics. Also, we check the thermodynamical equilibrium condition for two phases of creation rate, that is constant and variable Γ and found its vitality in all cases of entropy. (orig.)

  3. {alpha}-particle induced reactions on yttrium and terbium

    Energy Technology Data Exchange (ETDEWEB)

    Mukherjee, S.; Kumar, B.B. [School of Studies in Physics, Vikram University, Ujjain-456010 (India); Rashid, M.H. [Variable Energy Cyclotron Center, 1/AF, Bidhan Nagar, Calcutta (India); Chintalapudi, S.N. [Inter-University Consortium for DAE Facilities, 3/LB, Bidhan Nagar, Calcutta (India)

    1997-05-01

    The stacked foil activation technique has been employed for the investigation of {alpha}-particle induced reactions on the target elements yttrium and terbium up to 50 MeV. Six excitation functions for the ({alpha},xn) type of reactions were studied using high-resolution HPGe {gamma}-ray spectroscopy. A comparison with Blann{close_quote}s geometric dependent hybrid model has been made using the initial exciton number n{sub 0}=4(4p0h) and n{sub 0}=5(5p0h). A broad general agreement is observed between the experimental results and theoretical predictions with an initial exciton number n{sub 0}=4(4p0h). {copyright} {ital 1997} {ital The American Physical Society}

  4. α-particle induced reactions on yttrium and terbium

    International Nuclear Information System (INIS)

    Mukherjee, S.; Kumar, B.B.; Rashid, M.H.; Chintalapudi, S.N.

    1997-01-01

    The stacked foil activation technique has been employed for the investigation of α-particle induced reactions on the target elements yttrium and terbium up to 50 MeV. Six excitation functions for the (α,xn) type of reactions were studied using high-resolution HPGe γ-ray spectroscopy. A comparison with Blann close-quote s geometric dependent hybrid model has been made using the initial exciton number n 0 =4(4p0h) and n 0 =5(5p0h). A broad general agreement is observed between the experimental results and theoretical predictions with an initial exciton number n 0 =4(4p0h). copyright 1997 The American Physical Society

  5. Thermodynamics of gravitationally induced particle creation scenario in DGP braneworld

    International Nuclear Information System (INIS)

    Jawad, Abdul; Rani, Shamaila; Rafique, Salman

    2018-01-01

    In this paper, we discuss the thermodynamical analysis for gravitationally induced particle creation scenario in the framework of DGP braneworld model. For this purpose, we consider apparent horizon as the boundary of the universe. We take three types of entropy such as Bakenstein entropy, logarithmic corrected entropy and power law corrected entropy with ordinary creation rate Γ. We analyze the first law and generalized second law of thermodynamics analytically for these entropies which hold under some constraints. The behavior of total entropy in each case is also discussed which implies the validity of generalized second law of thermodynamics. Also, we check the thermodynamical equilibrium condition for two phases of creation rate, that is constant and variable Γ and found its vitality in all cases of entropy. (orig.)

  6. Antitumor bystander effect induced by radiation-inducible target gene therapy combined with α particle irradiation

    International Nuclear Information System (INIS)

    Liu Hui; Jin Chufeng; Wu Yican; Ge Shenfang; Wu Lijun; FDS Team

    2012-01-01

    In this work, we investigated the bystander effect of the tumor and normal cells surrounding the target region caused by radiation-inducible target gene therapy combined with α-particle irradiation. The receptor tumor cell A549 and normal cell MRC-5 were co-cultured with the donor cells irradiated to 0.5 Gy or the non-irradiated donor cells, and their survival and apoptosis fractions were evaluated. The results showed that the combined treatment of Ad-ET and particle irradiation could induce synergistic antitumor effect on A549 tumor cell, and the survival fraction of receptor cells co-cultured with the irradiated cells decreased by 6%, compared with receptor cells co-cultured with non-irradiated cells, and the apoptosis fraction increased in the same circumstance, but no difference was observed with the normal cells. This study demonstrates that Ad-ET combined with α-particle irradiation can significantly cause the bystander effect on neighboring tumor cells by inhibiting cell growth and inducing apoptosis, without obvious toxicity to normal cells. This suggests that combining radiation-inducible TRAIL gene therapy and irradiation may improve tumor treatment efficacy by specifically targeting tumor cells and even involving the neighboring tumor cells. (authors)

  7. Thermodynamic implications of the gravitationally induced particle creation scenario

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Subhajit [Indian Institute of Science Education and Research Kolkata, Department of Physical Sciences, Mohanpur, West Bengal (India); Mondal, Anindita [S N Bose National Centre for Basic Sciences, Department of Astrophysics and Cosmology, Kolkata, West Bengal (India)

    2017-03-15

    A rigorous thermodynamic analysis has been done as regards the apparent horizon of a spatially flat Friedmann-Lemaitre-Robertson-Walker universe for the gravitationally induced particle creation scenario with constant specific entropy and an arbitrary particle creation rate Γ. Assuming a perfect fluid equation of state p = (γ - 1)ρ with (2)/(3) ≤ γ ≤ 2, the first law, the generalized second law (GSL), and thermodynamic equilibrium have been studied, and an expression for the total entropy (i.e., horizon entropy plus fluid entropy) has been obtained which does not contain Γ explicitly. Moreover, a lower bound for the fluid temperature T{sub f} has also been found which is given by T{sub f} ≥ 8 (((3γ)/(2)-1)/((2)/(γ)-1)) H{sup 2}. It has been shown that the GSL is satisfied for (Γ)/(3H) ≤ 1. Further, when Γ is constant, thermodynamic equilibrium is always possible for (1)/(2) < (Γ)/(3H) < 1, while for (Γ)/(3H) ≤ min {(1)/(2), (2γ-2)/(3γ-2)} and (Γ)/(3H) ≥ 1, equilibrium can never be attained. Thermodynamic arguments also lead us to believe that during the radiation phase, Γ ≤ H. When Γ is not a constant, thermodynamic equilibrium holds if H ≥ (27)/(4) γ{sup 2}H{sup 3} (1-(Γ)/(3H)){sup 2}, however, such a condition is by no means necessary for the attainment of equilibrium. (orig.)

  8. Light-induced electronic non-equilibrium in plasmonic particles.

    Science.gov (United States)

    Kornbluth, Mordechai; Nitzan, Abraham; Seideman, Tamar

    2013-05-07

    We consider the transient non-equilibrium electronic distribution that is created in a metal nanoparticle upon plasmon excitation. Following light absorption, the created plasmons decohere within a few femtoseconds, producing uncorrelated electron-hole pairs. The corresponding non-thermal electronic distribution evolves in response to the photo-exciting pulse and to subsequent relaxation processes. First, on the femtosecond timescale, the electronic subsystem relaxes to a Fermi-Dirac distribution characterized by an electronic temperature. Next, within picoseconds, thermalization with the underlying lattice phonons leads to a hot particle in internal equilibrium that subsequently equilibrates with the environment. Here we focus on the early stage of this multistep relaxation process, and on the properties of the ensuing non-equilibrium electronic distribution. We consider the form of this distribution as derived from the balance between the optical absorption and the subsequent relaxation processes, and discuss its implication for (a) heating of illuminated plasmonic particles, (b) the possibility to optically induce current in junctions, and (c) the prospect for experimental observation of such light-driven transport phenomena.

  9. Thermodynamic implications of the gravitationally induced particle creation scenario

    International Nuclear Information System (INIS)

    Saha, Subhajit; Mondal, Anindita

    2017-01-01

    A rigorous thermodynamic analysis has been done as regards the apparent horizon of a spatially flat Friedmann-Lemaitre-Robertson-Walker universe for the gravitationally induced particle creation scenario with constant specific entropy and an arbitrary particle creation rate Γ. Assuming a perfect fluid equation of state p = (γ - 1)ρ with (2)/(3) ≤ γ ≤ 2, the first law, the generalized second law (GSL), and thermodynamic equilibrium have been studied, and an expression for the total entropy (i.e., horizon entropy plus fluid entropy) has been obtained which does not contain Γ explicitly. Moreover, a lower bound for the fluid temperature T f has also been found which is given by T f ≥ 8 (((3γ)/(2)-1)/((2)/(γ)-1)) H 2 . It has been shown that the GSL is satisfied for (Γ)/(3H) ≤ 1. Further, when Γ is constant, thermodynamic equilibrium is always possible for (1)/(2) < (Γ)/(3H) < 1, while for (Γ)/(3H) ≤ min {(1)/(2), (2γ-2)/(3γ-2)} and (Γ)/(3H) ≥ 1, equilibrium can never be attained. Thermodynamic arguments also lead us to believe that during the radiation phase, Γ ≤ H. When Γ is not a constant, thermodynamic equilibrium holds if H ≥ (27)/(4) γ 2 H 3 (1-(Γ)/(3H)) 2 , however, such a condition is by no means necessary for the attainment of equilibrium. (orig.)

  10. Charged particle induced thermonuclear reaction rates: a compilation for astrophysics

    International Nuclear Information System (INIS)

    Grama, C.

    1999-01-01

    We report on the results of the European network NACRE (Nuclear Astrophysics Compilation of REaction rates). The principal reason for setting up the NACRE network has been the necessity of building up a well-documented and detailed compilation of rates for charged-particle induced reactions on stable targets up to Si and on unstable nuclei of special significance in astrophysics. This work is meant to supersede the only existing compilation of reaction rates issued by Fowler and collaborators. The main goal of NACRE network was the transparency in the procedure of calculating the rates. More specifically this compilation aims at: 1. updating the experimental and theoretical data; 2. distinctly identifying the sources of the data used in rate calculation; 3. evaluating the uncertainties and errors; 4. providing numerically integrated reaction rates; 5. providing reverse reaction rates and analytical approximations of the adopted rates. The cross section data and/or resonance parameters for a total of 86 charged-particle induced reactions are given and the corresponding reaction rates are calculated and given in tabular form. Uncertainties are analyzed and realistic upper and lower bounds of the rates are determined. The compilation is concerned with the reaction rates that are large enough for the target lifetimes shorter than the age of the Universe, taken equal to 15 x 10 9 y. The reaction rates are provided for temperatures lower than T = 10 10 K. In parallel with the rate compilation a cross section data base has been created and located at the site http://pntpm.ulb.ac.be/nacre..htm. (authors)

  11. Optimization of fuel core loading pattern design in a VVER nuclear power reactors using Particle Swarm Optimization (PSO)

    International Nuclear Information System (INIS)

    Babazadeh, Davood; Boroushaki, Mehrdad; Lucas, Caro

    2009-01-01

    The two main goals in core fuel loading pattern design optimization are maximizing the core effective multiplication factor (K eff ) in order to extract the maximum energy, and keeping the local power peaking factor (P q ) lower than a predetermined value to maintain fuel integrity. In this research, a new strategy based on Particle Swarm Optimization (PSO) algorithm has been developed to optimize the fuel core loading pattern in a typical VVER. The PSO algorithm presents a simple social model by inspiration from bird collective behavior in finding food. A modified version of PSO algorithm for discrete variables has been developed and implemented successfully for the multi-objective optimization of fuel loading pattern design with constraints of keeping P q lower than a predetermined value and maximizing K eff . This strategy has been accomplished using WIMSD and CITATION calculation codes. Simulation results show that this algorithm can help in the acquisition of a new pattern without contravention of the constraints.

  12. Pulsed-induced electromagnetically induced transparency in the acetylene-filled hollow-core fibers

    Science.gov (United States)

    Rodríguez, Nayeli Casillas; Stepanov, Serguei; Miramontes, Manuel Ocegueda; Hernández, Eliseo Hernández

    2017-06-01

    Experimental results on pulsed excitation of electromagnetically induced transparency (EIT) in the acetylene-filled hollow-core photonic crystal fiber (HC-PCF) at pressures 0.1-0.4 Torr are reported. The EIT was observed both in Λ and V interaction configurations with the continuous probe wave tuned to R9 (1520.08 nm) acetylene absorption line and with the control pulses tuned to P11 (1531.58 nm) and P9 (1530.37 nm) lines, respectively. The utilized control pulses were of up to 40 ns duration with EIT was up to 40 and 15% for the co- and counter-propagation of the probe and control waves, respectively, and importance of the waves polarization matching was demonstrated. For a qualitative explanation of reduction in the counter-propagation EIT efficiency a simple model of the accelerated mismatch of the two-frequency EIT resonance with deviation of the molecule thermal velocity from the resonance value was utilized. It was shown experimentally that the EIT efficiencies in both configurations do not depend on the longitudinal velocity of the molecules. The characteristic relaxation time of the of the EIT response was found to be about 9 ns, i.e., is close to the relaxation times T 1,2 of the acetylene molecules under the utilized experimental conditions.

  13. Luminescence study on Eu3+ doped Y2O3 nanoparticles: particle size, concentration and core-shell formation effects

    International Nuclear Information System (INIS)

    Singh, L Robindro; Ningthoujam, R S; Sudarsan, V; Srivastava, Iti; Singh, S Dorendrajit; Dey, G K; Kulshreshtha, S K

    2008-01-01

    Nanoparticles of Eu 3+ doped Y 2 O 3 (core) and Eu 3+ doped Y 2 O 3 covered with Y 2 O 3 shell (core-shell) are prepared by urea hydrolysis for 3 h in ethylene glycol medium at a relatively low temperature of 140 deg. C, followed by heating at 500 and 900 deg. C. Particle sizes determined from x-ray diffraction and transmission electron microscopic studies are 11 and 18 nm for 500 and 900 deg. C heated samples respectively. Based on the luminescence studies of 500 and 900 deg. C heated samples, it is confirmed that there is no particle size effect on the peak positions of Eu 3+ emission, and optimum luminescence intensity is observed from the nanoparticles with a Eu 3+ concentration of 4-5 at.%. A luminescence study establishes that the Eu 3+ environment in amorphous Y (OH) 3 is different from that in crystalline Y 2 O 3 . For a fixed concentration of Eu 3+ doping, there is a reduction in Eu 3+ emission intensity for core-shell nanoparticles compared to that of core nanoparticles, and this has been attributed to the concentration dilution effect. Energy transfer from the host to Eu 3+ increases with increase of crystallinity

  14. Beam halo studies using a three-dimensional particle-core model

    Directory of Open Access Journals (Sweden)

    Ji Qiang

    2000-06-01

    Full Text Available In this paper we present a study of beam halo based on a three-dimensional particle-core model of an ellipsoidal bunched beam in a constant focusing channel including the effects of nonlinear rf focusing. For an initially mismatched beam, three linear envelope modes—a high frequency mode, a low frequency mode, and a quadrupole mode—are identified for an azimuthally symmetric bunched beam. The high frequency mode has three components all in phase; the low frequency mode has the transverse components in phase and the longitudinal component 180° out of phase; the quadrupole mode has no longitudinal component, and the two transverse components in the mode are 180° out of phase. We also study the case of an ellipsoidal bunched beam without azimuthal symmetry and find that the high frequency mode and the low frequency mode are still present but the quadrupole mode is replaced by a new mode with transverse components 180° out of phase and a nonzero longitudinal component. Previous studies, which generally addressed the situation where the longitudinal-to-transverse focusing strength is roughly 0.6 or less, conclude that the oscillation of the high frequency mode is predominantly transverse, and that of the low frequency mode is predominantly longitudinal. In this paper we present a systematic study of the features of the modes as a function of the longitudinal-to-transverse focusing strength ratio. We find that, when the ratio is greater than unity, the high frequency mode may contain a significant longitudinal component. Thus, excitation of the high frequency mode in this situation can be responsible for the formation of longitudinal beam halo. Furthermore, while previous studies have observed halo amplitudes roughly 2–3 times the matched beam edge, for the present parameters we observe much larger amplitudes (5 times or more. This is due to the fact that the longitudinal-to-transverse focusing ratio used here is greater than that of previous

  15. Development of polymer-biomolecule core-shell particles for biomedical applications

    Science.gov (United States)

    Suthiwangcharoen, Nisaraporn

    Developing efficient strategies to introduce biomolecules around polymeric nanoparticles (NPs) is critical for targeted delivery of therapeutic or diagnostic agents. Although polymeric NPs have been well established, problems such as toxicity, stability, and immunoresistance remain potential concerns. The first part of this dissertation focuses on the development of nanosized targeted drug delivery vehicle in cancer chemotherapy. The vehicle was created by the self-assembly of folate-grafted filamentous bacteriophage M13 with poly(caprolactone- b-2-vinylpyridine) while doxorubicin, the antitumor drugs, was successfully loaded in the interior of the vehicles. These particles offer unique properties of being able to selectively target tumor cells while appearing to be safe and non-toxic to normal cells. Although they have shown great prospects in many biomedical applications, less is known about the interactions between biomolecules and polymers. The next part of the dissertation focuses on the self-assembly of proteins and polymers to create polymer-protein core-shell nanoparticles (PPCS-NPs). Several proteins with different isoelectric points and molecular weights were employed to demonstrate a versatility of our assembly method while a series of esterified derivatives of poly(2-hydroxyethyl methacrylate) (pHEMA) were synthesized to evaluate the interaction between proteins and polymers. Our data indicated that the polymers containing pyridine residues can successfully assemble with proteins, and the mechanism is mainly governed by hydrogen bonding and the hydrophobic/hydrophilic interactions. This in turn helps retaining proteins' folding conformation and functionality, which are also demonstrated in the in vitro/in vivo cellular uptake of the PPCS-NPs in endothelial cells. The last part of the dissertation focuses on the self-assembly of the bienzyme-polymer NPs. Glucose oxidase (GOX) together with horseradish peroxidase (HRP) were employed to construct bienzyme

  16. Hepatitis C virus core protein induces hepatic steatosis via Sirt1-dependent pathway.

    Science.gov (United States)

    Zhang, Chuanhai; Wang, Jingjing; Zhang, Hanlin; Liu, Shunai; Lee, Hyuek Jong; Jin, Wanzhu; Cheng, Jun

    2018-05-01

    Hepatic steatosis is a common feature of patients with chronic hepatitis C. Previous reports have shown that the overexpression of hepatitis C virus core-encoding sequences (hepatitis C virus genotypes 3a and 1b) significantly induces intracellular triglyceride accumulation. However, the underlying mechanism has not yet been revealed. To investigate whether Sirt1 is involved in hepatitis C virus-mediated hepatic steatosis, the overexpression of hepatitis C virus core 1b protein and Sirt1 and the knockdown of Sirt1 in HepG2 cells were performed. To confirm the results of the cellular experiment liver-specific Sirt1 KO mice with lentivirus-mediated hepatitis C virus core 1b overexpression were studied. Our results show that hepatitis C virus core 1b protein overexpression led to the accumulation of triglycerides in HepG2 cells. Notably the expression of PPARγ2 was dramatically increased at both the mRNA and protein levels by hepatitis C virus core 1b overexpression. The protein expression of Sirt1 is an upstream regulator of PPARγ2 and was also significantly increased after core 1b overexpression. In addition, the overexpression or knockdown of Sirt1 expression alone was sufficient to modulate p300-mediated PPARγ2 deacetylation. In vivo studies showed that hepatitis C virus core protein 1b-induced hepatic steatosis was attenuated in liver-specific Sirt1 KO mice by downregulation of PPARγ2 expression. Sirt1 mediates hepatitis C virus core protein 1b-induced hepatic steatosis by regulation of PPARγ2 expression. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Field and laboratory investigations of coring-induced damage in core recovered from Marker Bed 139 at the waste isolation pilot plant underground facility

    International Nuclear Information System (INIS)

    Holcomb, D.J.; Zeuch, D.H.; Morin, K.; Hardy, R.; Tormey, T.V.

    1995-09-01

    A combined laboratory and field investigation was carried out to determine the extent of coring-induced damage done to samples cored from Marker Bed 139 at the WIPP site. Coring-induced damage, if present, has the potential to significantly change the properties of the material used for laboratory testing relative to the in situ material properties, resulting in misleading conclusions. In particular, connected, crack-like damage could make the permeability of cored samples orders of magnitude greater than the in situ permeabilities. Our approach compared in situ velocity and resistivity measurements with laboratory measurements of the same properties. Differences between in situ and laboratory results could be attributed to differences in the porosity due to cracks. The question of the origin of the changes could not be answered directly from the results of the measurements. Pre-existing cracks, held closed by the in situ stress, could open when the core was cut free, or new cracks could be generated by coring-induced damage. We used core from closely spaced boreholes at three orientations (0 degree, ±45 degrees relative to vertical) to address the origin of cracks. The absolute orientation of pre-existing cracks would be constant, independent of the borehole orientation. In contrast, cracks induced by coring were expected to show an orientation dependent on that of the source borehole

  18. Field and laboratory investigations of coring-induced damage in core recovered from Marker Bed 139 at the waste isolation pilot plant underground facility

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, D.J.; Zeuch, D.H.; Morin, K.; Hardy, R.; Tormey, T.V.

    1995-09-01

    A combined laboratory and field investigation was carried out to determine the extent of coring-induced damage done to samples cored from Marker Bed 139 at the WIPP site. Coring-induced damage, if present, has the potential to significantly change the properties of the material used for laboratory testing relative to the in situ material properties, resulting in misleading conclusions. In particular, connected, crack-like damage could make the permeability of cored samples orders of magnitude greater than the in situ permeabilities. Our approach compared in situ velocity and resistivity measurements with laboratory measurements of the same properties. Differences between in situ and laboratory results could be attributed to differences in the porosity due to cracks. The question of the origin of the changes could not be answered directly from the results of the measurements. Pre-existing cracks, held closed by the in situ stress, could open when the core was cut free, or new cracks could be generated by coring-induced damage. We used core from closely spaced boreholes at three orientations (0{degree}, {plus_minus}45{degrees} relative to vertical) to address the origin of cracks. The absolute orientation of pre-existing cracks would be constant, independent of the borehole orientation. In contrast, cracks induced by coring were expected to show an orientation dependent on that of the source borehole.

  19. Shape-Controlled Synthesis of Magnetic Iron Oxide@SiO₂-Au@C Particles with Core-Shell Nanostructures.

    Science.gov (United States)

    Li, Mo; Li, Xiangcun; Qi, Xinhong; Luo, Fan; He, Gaohong

    2015-05-12

    The preparation of nonspherical magnetic core-shell nanostructures with uniform sizes still remains a challenge. In this study, magnetic iron oxide@SiO2-Au@C particles with different shapes, such as pseduocube, ellipsoid, and peanut, were synthesized using hematite as templates and precursors of magnetic iron oxide. The as-obtained magnetic particles demonstrated uniform sizes, shapes, and well-designed core-shell nanostructures. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX) analysis showed that the Au nanoparticles (AuNPs) of ∼6 nm were uniformly distributed between the silica and carbon layers. The embedding of the metal nanocrystals into the two different layers prevented the aggregation and reduced the loss of the metal nanocrystals during recycling. Catalytic performance of the peanut-like particles kept almost unchanged without a noticeable decrease in the reduction of 4-nitrophenol (4-NP) in 8 min even after 7 cycles, indicating excellent reusability of the particles. Moreover, the catalyst could be readily recycled magnetically after each reduction by an external magnetic field.

  20. Polystyrene Core-Silica Shell Particles with Defined Nanoarchitectures as a Versatile Platform for Suspension Array Technology.

    Science.gov (United States)

    Sarma, Dominik; Gawlitza, Kornelia; Rurack, Knut

    2016-04-19

    The need for rapid and high-throughput screening in analytical laboratories has led to significant growth in interest in suspension array technologies (SATs), especially with regard to cytometric assays targeting a low to medium number of analytes. Such SAT or bead-based assays rely on spherical objects that constitute the analytical platform. Usually, functionalized polymer or silica (SiO2) microbeads are used which each have distinct advantages and drawbacks. In this paper, we present a straightforward synthetic route to highly monodisperse SiO2-coated polystyrene core-shell (CS) beads for SAT with controllable architectures from smooth to raspberry- and multilayer-like shells by varying the molecular weight of poly(vinylpyrrolidone) (PVP), which was used as the stabilizer of the cores. The combination of both organic polymer core and a structurally controlled inorganic SiO2 shell in one hybrid particle holds great promises for flexible next-generation design of the spherical platform. The particles were characterized by electron microscopy (SEM, T-SEM, and TEM), thermogravimetry, flow cytometry, and nitrogen adsorption/desorption, offering comprehensive information on the composition, size, structure, and surface area. All particles show ideal cytometric detection patterns and facile handling due to the hybrid structure. The beads are endowed with straightforward modification possibilities through the defined SiO2 shells. We successfully implemented the particles in fluorometric SAT model assays, illustrating the benefits of tailored surface area which is readily available for small-molecule anchoring. Very promising assay performance was shown for DNA hybridization assays with quantification limits down to 8 fmol.

  1. Particle sizes of Pliocene and Pleistocene core sediments from IODP Expedition 323 in the Bering Sea

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data compilation includes the results of grain size analyses of core sediment collected by IODP during Expedition 323 in the Bering Sea. One dataset is included...

  2. Study and analysis on the flow induced vibration of the core barrel of PWR

    International Nuclear Information System (INIS)

    Yao Weida; Shi Guolin; Jiang Nanyan; Peng YongYong; Zhang Huijun; Wang Yufen; Xie Yongcheng; Guo Chunhua; Shen Qinping

    1989-01-01

    The deduction of the resemblance criterion and the design of the test model by applying flow-solid coupling theory are described. The model analysis of a core barrel both in the air and stationary water were performed in a 1:10 model, thus obtaining the dynamic characteristic. In a 1:5 reactor model with a hydraulic closed loop, the inner structure and support were modeled for performing hydraulic closed loop, the inner structure and support were modeled for performing hydraulic vibration test of the core barrel. The flow induced pulse pressure of the core barrel and corresponding response were obtained by using miniature pressure capsule, strain gauge and accelerometer. Power spectrum, correlation functions, transfer function and amplitudes under different flow velocities were calculated. The hydraulic vibration test shows that the core barrel will be in safety during its 30-year life time

  3. Induced supersolidity in a mixture of normal and hard-core bosons

    International Nuclear Information System (INIS)

    Mishra, Tapan; Das, B. P.; Pai, Ramesh V.

    2010-01-01

    We present a scenario where a supersolid is induced in one of the components of a mixture of two species bosonic atoms where there are no long-range interactions. We study a system of normal and hard-core boson mixture with only the former possessing long-range interactions. We consider three cases: the first where the total density is commensurate and the other two where it is incommensurate to the lattice. By suitable choices of the densities of normal and hard-core bosons and the interaction strengths between them, we predict that the charge density wave and the supersolid orders can be induced in the hard-core species as a result of the competing interatomic interactions.

  4. Influence of core NA on thermal-induced mode instabilities in high power fiber amplifiers

    International Nuclear Information System (INIS)

    Tao, Rumao; Ma, Pengfei; Wang, Xiaolin; Zhou, Pu; Liu, Zejin

    2015-01-01

    We report on the influence of core NA on thermal-induced mode instabilities (MI) in high power fiber amplifiers. The influence of core NA and the V-parameter on MI has been investigated numerically. It shows that core NA has a larger influence on MI for fibers with a smaller core-cladding-ratio, and the influence of core NA on the threshold is more obvious when the amplifiers are pumped at 915 nm. The dependence of the threshold on the V-parameter revealed that the threshold increases linearly as the V-parameter decreases when the V-parameter is larger than 3.5, and the threshold shows an exponential increase as the V-parameter decreases when the V-parameter is less than 3.5. We also discussed the effect of linewidth on MI, which indicates that the influence of linewidth can be neglected for a linewidth smaller than 1 nm when the fiber core NA is smaller than 0.07 and the fiber length is shorter than 20 m. Fiber amplifiers with different core NA were experimentally analyzed, which agreed with the theoretical predictions. (letter)

  5. Thermodynamics inducing massive particles' tunneling and cosmic censorship

    International Nuclear Information System (INIS)

    Zhang, Baocheng; Cai, Qing-yu; Zhan, Ming-sheng

    2010-01-01

    By calculating the change of entropy, we prove that the first law of black hole thermodynamics leads to the tunneling probability of massive particles through the horizon, including the tunneling probability of massive charged particles from the Reissner-Nordstroem black hole and the Kerr-Newman black hole. Novelly, we find the trajectories of massive particles are close to that of massless particles near the horizon, although the trajectories of massive charged particles may be affected by electromagnetic forces. We show that Hawking radiation as massive particles tunneling does not lead to violation of the weak cosmic-censorship conjecture. (orig.)

  6. Thermodynamics inducing massive particles' tunneling and cosmic censorship

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Baocheng [Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Wuhan (China); Graduate University of Chinese Academy of Sciences, Beijing (China); Cai, Qing-yu [Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Wuhan (China); Zhan, Ming-sheng [Chinese Academy of Sciences, State Key Laboratory of Magnetic Resonances and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Wuhan (China); Chinese Academy of Sciences, Center for Cold Atom Physics, Wuhan (China)

    2010-08-15

    By calculating the change of entropy, we prove that the first law of black hole thermodynamics leads to the tunneling probability of massive particles through the horizon, including the tunneling probability of massive charged particles from the Reissner-Nordstroem black hole and the Kerr-Newman black hole. Novelly, we find the trajectories of massive particles are close to that of massless particles near the horizon, although the trajectories of massive charged particles may be affected by electromagnetic forces. We show that Hawking radiation as massive particles tunneling does not lead to violation of the weak cosmic-censorship conjecture. (orig.)

  7. Virus-like particles in venom of Meteorus pulchricornis induce host hemocyte apoptosis.

    Science.gov (United States)

    Suzuki, M; Tanaka, T

    2006-06-01

    Ultrastructural studies on the reproductive tract and venom apparatus of a female braconid, Meteorus pulchricornis, revealed that the parasitoid lacks the calyx region in its oviduct, but possesses a venom gland with two venom gland filaments and a venom reservoir filled with white and cloudy fluid. Its venom gland cell is concaved and has a lumen filled with numerous granules. Transmisson electron microscopic (TEM) observation revealed that virus-like particles (VLPs) were produced in venom gland cells. The virus-like particle observed in M. pulchricornis (MpVLP) is composed of membranous envelopes with two different parts: a high-density core and a whitish low-density part. The VLPs of M. pulchricornis is also found assembling ultimately in the lumen of venom gland cell. Microvilli were found thrusting into the lumen of the venom gland cell and seem to aid in driving the matured MpVLPs to the common duct of the venom gland filament. Injection of MpVLPs into non-parasitized Pseudaletia separata hosts induced apoptosis in hemocytes, particularly granulocytes (GRs). Rate of apoptosis induced in GRs peaked 48h after VLP injection. While a large part of the GR population collapsed due to apoptosis caused by MpVLPs, the plasmatocyte population was minimally affected. The capacity of MpVLPs to cause apoptosis in host's hemocytes was further demonstrated by a decrease ( approximately 10-fold) in ability of host hemocytes to encapsulate fluorescent latex beads when MpVLPs were present. Apparently, the reduced encapsulation ability was due to a decrease in the GR population resulting from MpVLP-induced apoptosis.

  8. Application of hepatitis B core particles produced by human primary hepatocellular carcinoma (PLC/342) propagated in nude mice to the determination of anti-HBc by passive hemagglutination.

    Science.gov (United States)

    Miyamoto, K; Itoh, Y; Tsuda, F; Matsui, T; Tanaka, T; Miyamoto, H; Naitoh, S; Imai, M; Usuda, S; Nakamura, T

    1986-05-22

    Human primary hepatocellular carcinoma (PLC/342), carried by nude mice, produces hepatitis B core particles as well as hepatitis B surface antigen particles. Core particles purified form PLC/342 tumors displayed epitopes of hepatitis B core antigen (HBcAg) but not epitopes of hepatitis B e antigen (HBeAg) on their surface, unlike core particles prepared from Dane particles, derived from plasma of asymptomatic carriers, that expressed epitopes of both HBcAg and HBeAg. Core particles obtained from PLC/342 tumors were applied to the determination of antibody to HBcAg (anti-HBc) by passive hemagglutination. The assay detected anti-HBc not only in individuals with persistent infection with hepatitis B virus and in those who had recovered from transient infection, but also in patients with acute type B hepatitis, indicating that it can detect anti-HBc of either IgG or IgM class. A liberal availability of core particles from tumors carried by nude mice, taken together with an easy applicability of the method, would make the passive hemagglutination for anti-HBc a valuable tool in clinical and epidemiological studies, especially in places where sophisticated methods are not feasible.

  9. Pellicular particles with spherical carbon cores and porous nanodiamond/polymer shells for reversed-phase HPLC.

    Science.gov (United States)

    Wiest, Landon A; Jensen, David S; Hung, Chuan-Hsi; Olsen, Rebecca E; Davis, Robert C; Vail, Michael A; Dadson, Andrew E; Nesterenko, Pavel N; Linford, Matthew R

    2011-07-15

    A new stationary phase for reversed-phase high performance liquid chromatography (RP HPLC) was created by coating spherical 3 μm carbon core particles in a layer-by-layer (LbL) fashion with poly(allylamine) (PAAm) and nanodiamond. Unfunctionalized core carbon particles were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and Raman spectroscopy. After LbL of PAAm and nanodiamond, which yields ca. 4 μm core-shell particles, the particles were simultaneously functionalized and cross-linked using a mixture of 1,2-epoxyoctadecane and 1,2,7,8-diepoxyoctane to obtain a mechanically stable C(18)/C(8) bonded outer layer. Core-shell particles were characterized by SEM, and their surface area, pore diameter, and volume were determined using the Brunauer-Emmett-Teller (BET) method. Short stainless steel columns (30 × 4.6 mm i.d.) were packed and the corresponding van Deemter plots obtained. The Supporting Information contains a MATLAB program used to fit the van Deemter data. The retentions of a suite of analytes were investigated on a conventional HPLC at various organic solvent compositions, pH values of mobile phases, including extreme pH values, and column temperatures. At 60 °C, a chromatogram of 2,6-diisopropylphenol showed 71,500 plates/m (N/m). Chromatograms obtained under acidic conditions (pH 2.7) of a mixture of acetaminophen, diazepam, and 2,6-diisopropylphenol and a mixture of phenol, 4-methylphenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol, and 1-tert-butyl-4-methylphenol are presented. Retention of amitriptyline, cholesterol, and diazinon at temperatures ranging from 35 to 80 °C and at pH 11.3 is reported. A series of five basic drugs was also separated at this pH. The stationary phase exhibits considerable hydrolytic stability at high pH (11.3) and even pH 13 over extended periods of time. An analysis run on a UHPLC with a "sandwich" injection

  10. Optically induced rotation of Rayleigh particles by vortex beams with different states of polarization

    International Nuclear Information System (INIS)

    Li, Manman; Yan, Shaohui; Yao, Baoli; Liang, Yansheng; Lei, Ming; Yang, Yanlong

    2016-01-01

    Optical vortex beams carry optical orbital angular momentum (OAM) and can induce an orbital motion of trapped particles in optical trapping. We show that the state of polarization (SOP) of vortex beams will affect the details of this optically induced orbital motion to some extent. Numerical results demonstrate that focusing the vortex beams with circular, radial or azimuthal polarizations can induce a uniform orbital motion on a trapped Rayleigh particle, while in the focal field of the vortex beam with linear polarization the particle experiences a non-uniform orbital motion. Among the formers, the vortex beam with circular polarization induces a maximum optical torque on the particle. Furthermore, by varying the topological charge of the vortex beams, the vortex beam with circular polarization gives rise to an optimum torque superior to those given by the other three vortex beams. These facts suggest that the circularly polarized vortex beam is more suitable for rotating particles. - Highlights: • States of polarization of vortex beams affect the optically induced orbital motion of particles. • The dependences of the force and orbital torque on the topological charge, the size and the absorptivity of particles were calculated. • Focused vortex beams with circular, radial or azimuthal polarizations induce a uniform orbital motion on particles. • Particles experience a non-uniform orbital motion in the focused linearly polarized vortex beam. • The circularly polarized vortex beam is a superior candidate for rotating particles.

  11. Chemodynamics of metal ion complexation by charged nanoparticles: a dimensionless rationale for soft, core-shell and hard particle types.

    Science.gov (United States)

    Duval, Jérôme F L

    2017-05-17

    Soft nanoparticulate complexants are defined by a spatial confinement of reactive sites and electric charges inside their 3D body. In turn, their reactivity with metal ions differs significantly from that of simple molecular ligands. A revisited form of the Eigen mechanism recently elucidated the processes leading to metal/soft particle pair formation. Depending on e.g. particle size and metal ion nature, chemodynamics of nanoparticulate metal complexes is controlled by metal conductive diffusion to/from the particles, by intraparticulate complex formation/dissociation kinetics, or by both. In this study, a formalism is elaborated to achieve a comprehensive and systematic identification of the rate-limiting step governing the overall formation and dissociation of nanoparticulate metal complexes. The theory covers the different types of spherical particulate complexants, i.e. 3D soft/permeable and core-shell particles, and hard particles with reactive sites at the surface. The nature of the rate-limiting step is formulated by a dynamical criterion involving a power law function of the ratio between particle radius and an intraparticulate reaction layer thickness defined by the key electrostatic, diffusional and kinetic components of metal complex formation/dissociation. The analysis clarifies the intertwined contributions of particle properties (size, soft or hard type, charge, density or number of reactive sites) and aqueous metal ion dehydration kinetics in defining the chemodynamic behavior of nanoparticulate metal complexes. For that purpose, fully parameterized chemodynamic portraits involving the defining features of particulate ligand and metal ion as well as the physicochemical conditions in the local intraparticulate environment, are constructed and thoroughly discussed under conditions of practical interest.

  12. Spectral Induced Polarization of Disseminated Pyrite Particles in Soil

    Science.gov (United States)

    Slater, L. D.; Kessouri, P.; Seleznev, N. V.

    2017-12-01

    Disseminated metallic particles in soil, particularly pyrite, occur naturally or are enhanced by anthropogenic activities. Detecting their presence and quantifying their concentration and location is of interest for numerous applications such as remediation of hydrocarbon contamination, mine tailings assessment, detection of oil traps, and archaeological studies. Because pyrite is a semiconductor, spectral induced polarization (SIP) is a promising geophysical method for sensing it in porous media. Previous studies have identified relations between pyrite properties (e.g., volumetric content, grain size) and SIP parameters (e.g., chargeability, relaxation time). However, the effect of pyrite grains in porous media on the SIP response is not fully understood over the entire low-frequency range. We tested the relationship between the presence of pyrite grains and the change in electrical properties of the medium through an extended series of laboratory measurements: (1) variation of grain size, (2) variation of grain concentration, (3) variation of electrolyte conductivity, (4) change in the diffusion properties of the host medium. For the fourth set of measurements, we compared sand columns to agar gel columns. Our experimental design included more than 20 different samples with multiple repeats to ensure representative results. We confirm the strong relation between grain size and relaxation time and that between grain concentration and chargeability in both the sand and agar gel samples. Furthermore, our results shed light on the significance of the diffusion coefficient and the recently hypothesized role of pyrite grains as resistors at frequencies lower than the relaxation frequency.

  13. Experimental particle acceleration by water evaporation induced by shock waves

    Science.gov (United States)

    Scolamacchia, T.; Alatorre Ibarguengoitia, M.; Scheu, B.; Dingwell, D. B.; Cimarelli, C.

    2010-12-01

    Shock waves are commonly generated during volcanic eruptions. They induce sudden changes in pressure and temperature causing phase changes. Nevertheless, their effects on flowfield properties are not well understood. Here we investigate the role of gas expansion generated by shock wave propagation in the acceleration of ash particles. We used a shock tube facility consisting of a high-pressure (HP) steel autoclave (450 mm long, 28 mm in internal diameter), pressurized with Ar gas, and a low-pressure tank at atmospheric conditions (LP). A copper diaphragm separated the HP autoclave from a 180 mm tube (PVC or acrylic glass) at ambient P, with the same internal diameter of the HP reservoir. Around the tube, a 30 cm-high acrylic glass cylinder, with the same section of the LP tank (40 cm), allowed the observation of the processes occurring downstream from the nozzle throat, and was large enough to act as an unconfined volume in which the initial diffracting shock and gas jet expand. All experiments were performed at Pres/Pamb ratios of 150:1. Two ambient conditions were used: dry air and air saturated with steam. Carbon fibers and glass spheres in a size range between 150 and 210 μm, were placed on a metal wire at the exit of the PVC tube. The sudden decompression of the Ar gas, due to the failure of the diaphragm, generated an initial air shock wave. A high-speed camera recorded the processes between the first 100 μsec and several ms after the diaphragm failure at frame rates ranging between 30,000 and 50,000 fps. In the experiments with ambient air saturated with steam, the high-speed camera allowed to visualize the condensation front associated with the initial air shock; a maximum velocity of 788 m/s was recorded, which decreases to 524 m/s at distance of 0.5 ±0.2 cm, 1.1 ms after the diaphragm rupture. The condensation front preceded the Ar jet front exhausting from the reservoir, by 0.2-0.5 ms. In all experiments particles velocities following the initial

  14. Influence of core size on the upconversion luminescence properties of spherical Gd2O3:Yb3+/Er3+@SiO2 particles with core-shell structures

    International Nuclear Information System (INIS)

    Zheng, Kezhi; Liu, Zhenyu; Liu, Ye; Song, Weiye; Qin, Weiping

    2013-01-01

    Spherical SiO 2 particles with different sizes (30, 80, 120, and 180 nm) have been coated with Gd 2 O 3 :Yb 3+ /Er 3+ layers by a heterogeneous precipitation method, leading to the formation of core-shell structural Gd 2 O 3 :Yb 3+ /Er 3+ @SiO 2 particles. The samples were characterized by using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, upconversion (UC) emission spectra, and fluorescent dynamical analysis. The obtained core-shell particles have perfect spherical shape with narrow size distribution. Under the excitation of 980 nm diode laser, the core-shell samples showed size-dependent upconversion luminescence (UCL) properties. The inner SiO 2 cores in core-shell samples were proved to have limited effect on the total UCL intensities of Er 3+ ions. The UCL intensities of core-shell particles were demonstrated much higher than the values obtained in pure Gd 2 O 3 :Yb 3+ /Er 3+ with the same phosphor volume. The dependence of the specific area of a UCL shell on the size of its inner SiO 2 particle was calculated and analyzed for the first time. It was confirmed that the surface effect came from the outer surfaces of emitting shells is dominant in influencing the UCL property in the core-shell samples. Three-photon UC processes for the green emissions were observed in the samples with small sizes of SiO 2 cores. The results of dynamical analysis illustrated that more nonradiative relaxation occurred in the core-shell samples with smaller SiO 2 core sizes

  15. Particle dispersion and mixing induced by breaking internal gravity waves

    Science.gov (United States)

    Bouruet-Aubertot, Pascale; Koudella, C.; Staquet, C.; Winters, K. B.

    2001-01-01

    The purpose of this paper is to analyze diapycnal mixing induced by the breaking of an internal gravity wave — the primary wave — either standing or propagating. To achieve this aim we apply two different methods. The first method consists of a direct estimate of vertical eddy diffusion from particle dispersion while the second method relies upon potential energy budgets [Winters, K.B., Lombard, P.N., Riley, J.J., D'Asaro, E.A., 1995. J. Fluid Mech. 289, 115-128; Winters, K.B., D'Asaro, E.A., 1996. J. Fluid Mech. 317, 179-193]. The primary wave we consider is of small amplitude and is statically stable, a case for which the breaking process involves two-dimensional instabilities. The dynamics of the waves have been previously analyzed by means of two-dimensional direct numerical simulations [Bouruet-Aubertot, P., Sommeria, J., Staquet, C., 1995. J. Fluid Mech. 285, 265-301; Bouruet-Aubertot, P., Sommeria, J., Staquet, C., 1996. Dyn. Atmos. Oceans 29, 41-63; Koudella, C., Staquet, C., 1998. In: Davis, P. (Ed.), Proceedings of the IMA Conference on Mixing and Dispersion on Stably-stratified Flows, Dundee, September 1996. IMA Publication]. High resolution three-dimensional calculations of the same wave are also reported here [Koudella, C., 1999]. A local estimate of mixing is first inferred from the time evolution of sets of particles released in the flow during the breaking regime. We show that, after an early evolution dominated by shear effects, a diffusion law is reached and the dispersion coefficient is fairly independent of the initial seeding location of the particles in the flow. The eddy diffusion coefficient, K, is then estimated from the diapycnal diffusive flux. A good agreement with the value inferred from particle dispersion is obtained. This finding is of particular interest regarding the interpretation of in situ estimates of K inferred either from tracer dispersion or from microstructure measurements. Computation of the Cox number, equal to the

  16. Quantitative cellular uptake of double fluorescent core-shelled model submicronic particles

    Energy Technology Data Exchange (ETDEWEB)

    Leclerc, Lara, E-mail: leclerc@emse.fr [Ecole Nationale Superieure des Mines, CIS-EMSE, LINA (France); Boudard, Delphine [LINA (France); Pourchez, Jeremie; Forest, Valerie [Ecole Nationale Superieure des Mines, CIS-EMSE, LINA (France); Marmuse, Laurence; Louis, Cedric [NANO-H S.A.S (France); Bin, Valerie [LINA (France); Palle, Sabine [Universite Jean Monnet, Centre de Microscopie Confocale Multiphotonique (France); Grosseau, Philippe; Bernache-Assollant, Didier [Ecole Nationale Superieure des Mines, CIS-EMSE, LINA (France); Cottier, Michele [LINA (France)

    2012-11-15

    The relationship between particles' physicochemical parameters, their uptake by cells and their degree of biological toxicity represent a crucial issue, especially for the development of new technologies such as fabrication of micro- and nanoparticles in the promising field of drug delivery systems. This work was aimed at developing a proof-of-concept for a novel model of double fluorescence submicronic particles that could be spotted inside phagolysosomes. Fluorescein isothiocyanate (FITC) particles were synthesized and then conjugated with a fluorescent pHrodo Trade-Mark-Sign probe, red fluorescence of which increases in acidic conditions such as within lysosomes. After validation in acellular conditions by spectral analysis with confocal microscopy and dynamic light scattering, quantification of phagocytosis was conducted on a macrophage cell line in vitro. The biological impact of pHrodo functionalization (cytotoxicity, inflammatory response, and oxidative stress) was also investigated. Results validate the proof-of-concept of double fluorescent particles (FITC + pHrodo), allowing detection of entirely engulfed pHrodo particles (green and red labeling). Moreover incorporation of pHrodo had no major effects on cytotoxicity compared to particles without pHrodo, making them a powerful tool for micro- and nanotechnologies.

  17. New Small LWR Core Designs using Particle Burnable Poisons for Low Boron Concentration

    International Nuclear Information System (INIS)

    Yoo, Ho Seong; Hwang, Dae Hee; Hong, Ser Gi

    2015-01-01

    The soluble boron has two major important roles in commercial PWR operations : 1) the control of the long-term reactivity to maintain criticality under normal operation, and 2) the shutdown of the reactor under accidents. However, the removal of the soluble boron gives several advantages in SMRs (Small Modular Reactor). These advantages resulted from the elimination of soluble boron include the significant simplification of nuclear power plant through the removal of pipes, pumps, and purification systems. Also, the use of soluble boron mitigates corrosion problems on the primary coolant loop. Furthermore, the soluble boron-free operation can remove an inadvertent boron dilution accident (BDA) which can lead to a significant insertion of positive reactivity. From the viewpoint of core physics, the removal of soluble boron or reduction of soluble boron concentration makes the moderator temperature coefficient (MTC) more negative. From the core design studies using new fuel assemblies, it is shown that the cores have very low critical soluble boron concentrations less than 500ppm, low peaking factors within the design targets, strong negative MTCs over cycles, and large enough shutdown margins both at BOC and EOC. However, the present cores have relatively low average discharge burnups of ∼ 30MWD/kg leading to low fuel economy because the cores use lots of non-fuel burnable poison rods to achieve very low critical boron concentrations. So, in the future, we will perform the trade-off study between the fuel discharge burnup and the boron concentrations by changing fuel assembly design and the core loading pattern

  18. New Small LWR Core Designs using Particle Burnable Poisons for Low Boron Concentration

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Ho Seong; Hwang, Dae Hee; Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of)

    2015-05-15

    The soluble boron has two major important roles in commercial PWR operations : 1) the control of the long-term reactivity to maintain criticality under normal operation, and 2) the shutdown of the reactor under accidents. However, the removal of the soluble boron gives several advantages in SMRs (Small Modular Reactor). These advantages resulted from the elimination of soluble boron include the significant simplification of nuclear power plant through the removal of pipes, pumps, and purification systems. Also, the use of soluble boron mitigates corrosion problems on the primary coolant loop. Furthermore, the soluble boron-free operation can remove an inadvertent boron dilution accident (BDA) which can lead to a significant insertion of positive reactivity. From the viewpoint of core physics, the removal of soluble boron or reduction of soluble boron concentration makes the moderator temperature coefficient (MTC) more negative. From the core design studies using new fuel assemblies, it is shown that the cores have very low critical soluble boron concentrations less than 500ppm, low peaking factors within the design targets, strong negative MTCs over cycles, and large enough shutdown margins both at BOC and EOC. However, the present cores have relatively low average discharge burnups of ∼ 30MWD/kg leading to low fuel economy because the cores use lots of non-fuel burnable poison rods to achieve very low critical boron concentrations. So, in the future, we will perform the trade-off study between the fuel discharge burnup and the boron concentrations by changing fuel assembly design and the core loading pattern.

  19. Influence of radiation induced defect clusters on silicon particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Junkes, Alexandra

    2011-10-15

    The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) addresses some of today's most fundamental questions of particle physics, like the existence of the Higgs boson and supersymmetry. Two large general-purpose experiments (ATLAS, CMS) are installed to detect the products of high energy protonproton and nucleon-nucleon collisions. Silicon detectors are largely employed in the innermost region, the tracking area of the experiments. The proven technology and large scale availability make them the favorite choice. Within the framework of the LHC upgrade to the high-luminosity LHC, the luminosity will be increased to L=10{sup 35} cm{sup -2}s{sup -1}. In particular the pixel sensors in the innermost layers of the silicon trackers will be exposed to an extremely intense radiation field of mainly hadronic particles with fluences of up to {phi}{sub eq}=10{sup 16} cm{sup -2}. The radiation induced bulk damage in silicon sensors will lead to a severe degradation of the performance during their operational time. This work focusses on the improvement of the radiation tolerance of silicon materials (Float Zone, Magnetic Czochralski, epitaxial silicon) based on the evaluation of radiation induced defects in the silicon lattice using the Deep Level Transient Spectroscopy and the Thermally Stimulated Current methods. It reveals the outstanding role of extended defects (clusters) on the degradation of sensor properties after hadron irradiation in contrast to previous works that treated effects as caused by point defects. It has been found that two cluster related defects are responsible for the main generation of leakage current, the E5 defects with a level in the band gap at E{sub C}-0.460 eV and E205a at E{sub C}-0.395 eV where E{sub C} is the energy of the edge of the conduction band. The E5 defect can be assigned to the tri-vacancy (V{sub 3}) defect. Furthermore, isochronal annealing experiments have shown that the V{sub 3} defect

  20. Influence of radiation induced defect clusters on silicon particle detectors

    International Nuclear Information System (INIS)

    Junkes, Alexandra

    2011-10-01

    The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) addresses some of today's most fundamental questions of particle physics, like the existence of the Higgs boson and supersymmetry. Two large general-purpose experiments (ATLAS, CMS) are installed to detect the products of high energy protonproton and nucleon-nucleon collisions. Silicon detectors are largely employed in the innermost region, the tracking area of the experiments. The proven technology and large scale availability make them the favorite choice. Within the framework of the LHC upgrade to the high-luminosity LHC, the luminosity will be increased to L=10 35 cm -2 s -1 . In particular the pixel sensors in the innermost layers of the silicon trackers will be exposed to an extremely intense radiation field of mainly hadronic particles with fluences of up to Φ eq =10 16 cm -2 . The radiation induced bulk damage in silicon sensors will lead to a severe degradation of the performance during their operational time. This work focusses on the improvement of the radiation tolerance of silicon materials (Float Zone, Magnetic Czochralski, epitaxial silicon) based on the evaluation of radiation induced defects in the silicon lattice using the Deep Level Transient Spectroscopy and the Thermally Stimulated Current methods. It reveals the outstanding role of extended defects (clusters) on the degradation of sensor properties after hadron irradiation in contrast to previous works that treated effects as caused by point defects. It has been found that two cluster related defects are responsible for the main generation of leakage current, the E5 defects with a level in the band gap at E C -0.460 eV and E205a at E C -0.395 eV where E C is the energy of the edge of the conduction band. The E5 defect can be assigned to the tri-vacancy (V 3 ) defect. Furthermore, isochronal annealing experiments have shown that the V 3 defect exhibits a bistability, as does the leakage current. In oxygen

  1. Multilevel parallel strategy on Monte Carlo particle transport for the large-scale full-core pin-by-pin simulations

    International Nuclear Information System (INIS)

    Zhang, B.; Li, G.; Wang, W.; Shangguan, D.; Deng, L.

    2015-01-01

    This paper introduces the Strategy of multilevel hybrid parallelism of JCOGIN Infrastructure on Monte Carlo Particle Transport for the large-scale full-core pin-by-pin simulations. The particle parallelism, domain decomposition parallelism and MPI/OpenMP parallelism are designed and implemented. By the testing, JMCT presents the parallel scalability of JCOGIN, which reaches the parallel efficiency 80% on 120,000 cores for the pin-by-pin computation of the BEAVRS benchmark. (author)

  2. Toxicogenomic analysis of the particle dose- and size-response relationship of silica particles-induced toxicity in mice

    International Nuclear Information System (INIS)

    Lu Xiaoyan; Jin Tingting; Jin Yachao; Wu Leihong; Hu Bin; Tian Yu; Fan Xiaohui

    2013-01-01

    This study investigated the relationship between particle size and toxicity of silica particles (SP) with diameters of 30, 70, and 300 nm, which is essential to the safe design and application of SP. Data obtained from histopathological examinations suggested that SP of these sizes can all induce acute inflammation in the liver. In vivo imaging showed that intravenously administrated SP are mainly present in the liver, spleen and intestinal tract. Interestingly, in gene expression analysis, the cellular response pathways activated in the liver are predominantly conserved independently of particle dose when the same size SP are administered or are conserved independently of particle size, surface area and particle number when nano- or submicro-sized SP are administered at their toxic doses. Meanwhile, integrated analysis of transcriptomics, previous metabonomics and conventional toxicological results support the view that SP can result in inflammatory and oxidative stress, generate mitochondrial dysfunction, and eventually cause hepatocyte necrosis by neutrophil-mediated liver injury. (paper)

  3. Influence of Magnolol on the bystander effect induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W.; Law, Y.L. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, the influence of Magnolol on the bystander effect in alpha-particle irradiated Chinese hamster ovary (CHO) cells was examined. The bystander effect was studied through medium transfer experiments. Cytokinesis-block micronucleus (CBMN) assay was performed to quantify the chromosome damage induced by alpha-particle irradiation. Our results showed that the alpha-particle induced micronuclei (MN) frequencies were suppressed with the presence of Magnolol.

  4. Cement analysis by particle-induced prompt photon spectrometry: comparison of the effect of different charged particle beams

    International Nuclear Information System (INIS)

    Gihwala, D.; Peisach, M.

    1985-01-01

    Standard cements were analysed by particle-induced prompt photon spectrometry (PIPPS) using 4,75-MeV protons, 5-MeV 4 He+ ions, and 2-MeV deuterons. Precision and sensitivity attainable were compared. Protons and alpha-particles were comparable for the determination of F, Na, Mg and Si. Protons were preferred for P and Ca, and alpha-particles for the direct determination of O. Sources of interference are discussed with particular reference to delayed gamma-ray emission from deuteron bombardment

  5. Graphene supported Sn-Sb rate at carbon core-shell particles as a superior anode for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shuangqiang; Chen, Peng; Wang, Yong [Department of Chemical Engineering, School of Environmental and Chemical Engineering, Shanghai University (China); Wu, Minghong; Pan, Dengyu [Institute of Nanochemistry and Nanobiology, Shanghai Univ. (China)

    2010-10-15

    This paper reports the preparation and Li-storage properties of graphene nanosheets(GNS), GNS supported Sn-Sb rate at carbon (50-150 nm) and Sn-Sb nanoparticles (5-10 nm). The best cycling performance and excellent high rate capabilities were observed for GNS-supported Sn-Sb rate at carbon core-shell particles, which exhibited initial capacities of 978, 850 and 668 mAh/g respectively at 0.1C, 2C and 5C (1C = 800 mA/g) with good cyclability. Besides the GNS support, the carbon skin around Sn-Sb particles is believed to be a key factor to improve electrochemical properties of Sn-Sb. (author)

  6. High-resolution analytical imaging and electron holography of magnetite particles in amyloid cores of Alzheimer’s disease

    Science.gov (United States)

    Plascencia-Villa, Germán; Ponce, Arturo; Collingwood, Joanna F.; Arellano-Jiménez, M. Josefina; Zhu, Xiongwei; Rogers, Jack T.; Betancourt, Israel; José-Yacamán, Miguel; Perry, George

    2016-01-01

    Abnormal accumulation of brain metals is a key feature of Alzheimer’s disease (AD). Formation of amyloid-β plaque cores (APC) is related to interactions with biometals, especially Fe, Cu and Zn, but their particular structural associations and roles remain unclear. Using an integrative set of advanced transmission electron microscopy (TEM) techniques, including spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM), nano-beam electron diffraction, electron holography and analytical spectroscopy techniques (EDX and EELS), we demonstrate that Fe in APC is present as iron oxide (Fe3O4) magnetite nanoparticles. Here we show that Fe was accumulated primarily as nanostructured particles within APC, whereas Cu and Zn were distributed through the amyloid fibers. Remarkably, these highly organized crystalline magnetite nanostructures directly bound into fibrillar Aβ showed characteristic superparamagnetic responses with saturated magnetization with circular contours, as observed for the first time by off-axis electron holography of nanometer scale particles. PMID:27121137

  7. Universal analytical scattering form factor for shell-, core-shell, or homogeneous particles with continuously variable density profile shape.

    Science.gov (United States)

    Foster, Tobias

    2011-09-01

    A novel analytical and continuous density distribution function with a widely variable shape is reported and used to derive an analytical scattering form factor that allows us to universally describe the scattering from particles with the radial density profile of homogeneous spheres, shells, or core-shell particles. Composed by the sum of two Fermi-Dirac distribution functions, the shape of the density profile can be altered continuously from step-like via Gaussian-like or parabolic to asymptotically hyperbolic by varying a single "shape parameter", d. Using this density profile, the scattering form factor can be calculated numerically. An analytical form factor can be derived using an approximate expression for the original Fermi-Dirac distribution function. This approximation is accurate for sufficiently small rescaled shape parameters, d/R (R being the particle radius), up to values of d/R ≈ 0.1, and thus captures step-like, Gaussian-like, and parabolic as well as asymptotically hyperbolic profile shapes. It is expected that this form factor is particularly useful in a model-dependent analysis of small-angle scattering data since the applied continuous and analytical function for the particle density profile can be compared directly with the density profile extracted from the data by model-free approaches like the generalized inverse Fourier transform method. © 2011 American Chemical Society

  8. Energetic-particle-driven instabilities and induced fast-ion transport in a reversed field pinch

    International Nuclear Information System (INIS)

    Lin, L.; Brower, D. L.; Ding, W. X.; Anderson, J. K.; Capecchi, W.; Eilerman, S.; Forest, C. B.; Koliner, J. J.; Nornberg, M. D.; Reusch, J.; Sarff, J. S.; Liu, D.

    2014-01-01

    Multiple bursty energetic-particle (EP) driven modes with fishbone-like structure are observed during 1 MW tangential neutral-beam injection in a reversed field pinch (RFP) device. The distinguishing features of the RFP, including large magnetic shear (tending to add stability) and weak toroidal magnetic field (leading to stronger drive), provide a complementary environment to tokamak and stellarator configurations for exploring basic understanding of EP instabilities. Detailed measurements of the EP mode characteristics and temporal-spatial dynamics reveal their influence on fast ion transport. Density fluctuations exhibit a dynamically evolving, inboard-outboard asymmetric spatial structure that peaks in the core where fast ions reside. The measured mode frequencies are close to the computed shear Alfvén frequency, a feature consistent with continuum modes destabilized by strong drive. The frequency pattern of the dominant mode depends on the fast-ion species. Multiple frequencies occur with deuterium fast ions compared to single frequency for hydrogen fast ions. Furthermore, as the safety factor (q) decreases, the toroidal mode number of the dominant EP mode transits from n=5 to n=6 while retaining the same poloidal mode number m=1. The transition occurs when the m=1, n=5 wave-particle resonance condition cannot be satisfied as the fast-ion safety factor (q fi ) decreases. The fast-ion temporal dynamics, measured by a neutral particle analyzer, resemble a classical predator-prey relaxation oscillation. It contains a slow-growth phase arising from the beam fueling followed by a rapid drop when the EP modes peak, indicating that the fluctuation-induced transport maintains a stiff fast-ion density profile. The inferred transport rate is strongly enhanced with the onset of multiple EP modes

  9. Flow field induced particle accumulation inside droplets in rectangular channels.

    Science.gov (United States)

    Hein, Michael; Moskopp, Michael; Seemann, Ralf

    2015-07-07

    Particle concentration is a basic operation needed to perform washing steps or to improve subsequent analysis in many (bio)-chemical assays. In this article we present field free, hydrodynamic accumulation of particles and cells in droplets flowing within rectangular micro-channels. Depending on droplet velocity, particles either accumulate at the rear of the droplet or are dispersed over the entire droplet cross-section. We show that the observed particle accumulation behavior can be understood by a coupling of particle sedimentation to the internal flow field of the droplet. The changing accumulation patterns are explained by a qualitative change of the internal flow field. The topological change of the internal flow field, however, is explained by the evolution of the droplet shape with increasing droplet velocity altering the friction with the channel walls. In addition, we demonstrate that accumulated particles can be concentrated, removing excess dispersed phase by splitting the droplet at a simple channel junction.

  10. A characterisation of the magnetically induced movement of NdFeB-particles in magnetorheological elastomers

    Science.gov (United States)

    Schümann, M.; Borin, D. Y.; Huang, S.; Auernhammer, G. K.; Müller, R.; Odenbach, S.

    2017-09-01

    Magnetorheological elastomers are a type of smart hybrid material where elastic properties of a soft elastomer matrix are combined with magnetic properties of magnetic micro particles. This combination leads to a complex interplay of magnetic and elastic phenomena, of which the magnetorheological effect is the best described. In this paper, magnetically hard NdFeB-particles were used to obtain remanent magnetic properties. X-ray microtomography has been utilised to analyse the particle movement induced by magnetic fields. A particle tracking was performed; thus, it was possible to characterise the movement of individual particles. Beyond that, a comprehensive analysis of the orientation of all particles was performed at different states of magnetisation and global particle arrangements. For the first time, this method was successfully applied to a magnetorheological material with a technically relevant amount of magnetic NdFeB-particles. A significant impact of the magnetic field on the rotation and translation of the particles was shown.

  11. Synthesis of Co/MFe(2)O(4) (M = Fe, Mn) Core/Shell Nanocomposite Particles.

    Science.gov (United States)

    Peng, Sheng; Xie, Jin; Sun, Shouheng

    2008-01-01

    Monodispersed cobalt nanoparticles (NPs) with controllable size (8-14 nm) have been synthesized using thermal decomposition of dicobaltoctacarbonyl in organic solvent. The as-synthesized high magnetic moment (125 emu/g) Co NPs are dispersible in various organic solvents, and can be easily transferred into aqueous phase by surface modification using phospholipids. However, the modified hydrophilic Co NPs are not stable as they are quickly oxidized, agglomerated in buffer. Co NPs are stabilized by coating the MFe(2)O(4) (M = Fe, Mn) ferrite shell. Core/shell structured bimagnetic Co/MFe(2)O(4) nanocomposites are prepared with tunable shell thickness (1-5 nm). The Co/MFe(2)O(4) nanocomposites retain the high magnetic moment density from the Co core, while gaining chemical and magnetic stability from the ferrite shell. Comparing to Co NPs, the nanocomposites show much enhanced stability in buffer solution at elevated temperatures, making them promising for biomedical applications.

  12. Cr/alpha-Cr2O3 monodispersed spherical core-shell particles based solar absorbers

    CSIR Research Space (South Africa)

    Khamlich, S

    2011-07-01

    Full Text Available as reported. The coated Cr/alpha-Cr2O3 spherical particles on rough copper substrates by a simple self-assembly-like method were characterized by scanning electron microscopy, energy dispersive spectrometry, Raman spectroscopy, and diffuse reflectance UV...

  13. Adsorption of immunoglobulin G on core-shell latex particles precoated with chaps

    NARCIS (Netherlands)

    Giacomelli, CE; Vermeer, AWP; Norde, W

    2000-01-01

    The aim of this work is to investigate the adsorption behavior of a monoclonal antibody (immunoglobulin G, IgG) on latex particles, possessing reactive chloromethyl groups, precoated with 3-([3-cholamidopropyl]dimethylammonio-1-propansulfonate (Chaps). The amount and reactivity of the surface

  14. Adsorption of immunoglobulin G on core-shell latex particles precoated with chaps

    NARCIS (Netherlands)

    Giacomelli, C.E.; Vermeer, A.W.P.; Norde, W.

    2000-01-01

    The aim of this work is to investigate the adsorption behavior of a monoclonal antibody (immunoglobulin G, IgG) on latex particles, possessing reactive chloromethyl groups, precoated with 3-([3-cholamidopropyl]dimethylammonio-1-propanesulfonate (Chaps). The amount and reactivity of the surface

  15. Utterance-final particles in Taiwan Mandarin : contact, context and core functions

    NARCIS (Netherlands)

    Lin, Chin-hui

    2014-01-01

    The use of utterance-final particles (UFPs) is a salient feature of Taiwan Mandarin, a Mandarin variety spoken in Taiwan. Despite their widespread use, Taiwan Mandarin UFPs have not attracted much attention in previous research. One reason for this neglect is that previous studies focus on UFPs that

  16. Inhibiting core fucosylation attenuates glucose-induced peritoneal fibrosis in rats.

    Science.gov (United States)

    Li, Longkai; Shen, Nan; Wang, Nan; Wang, Weidong; Tang, Qingzhu; Du, Xiangning; Carrero, Juan Jesus; Wang, Keping; Deng, Yiyao; Li, Zhitong; Lin, Hongli; Wu, Taihua

    2018-06-01

    Ultrafiltration failure is a major complication of long-term peritoneal dialysis, resulting in dialysis failure. Peritoneal fibrosis induced by continuous exposure to high glucose dialysate is the major contributor of ultrafiltration failure, for which there is no effective treatment. Overactivation of several signaling pathways, including transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor (PDGF) pathways, contribute to the development of peritoneal fibrosis. Therefore, simultaneously blocking multiple signaling pathways might be a potential novel method of treating peritoneal fibrosis. Previously, we showed that core fucosylation, an important posttranslational modification of the TGF-β1 receptors, can regulate the activation of TGF-β1 signaling in renal interstitial fibrosis. However, it remains unclear whether core fucosylation affects the progression of peritoneal fibrosis. Herein, we show that core fucosylation was enriched in the peritoneal membrane of rats accompanied by peritoneal fibrosis induced by a high glucose dialysate. Blocking core fucosylation dramatically attenuated peritoneal fibrosis in the rat model achieved by simultaneously inactivating the TGF-β1 and PDGF signaling pathways. Next the protective effects of blocking core fucosylation and imatinib (a selective PDGF receptor inhibitor) on peritoneal fibrosis were compared and found to exhibit a greater inhibitory effect over imatinib alone, suggesting that blocking activation of multiple signaling pathways may have superior inhibitory effects on the development of peritoneal fibrosis. Thus, core fucosylation is essential for the development of peritoneal fibrosis by regulating the activation of multiple signaling pathways. This may be a potential novel target for drug development to treat peritoneal fibrosis. Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

  17. Preparation of surface imprinted core-shell particles via a metal chelating strategy: specific recognition of porcine serum albumin

    International Nuclear Information System (INIS)

    Li, Qinran; Li, Senwu; Liu, Lukuan; Yang, Kaiguang; Zhang, Lihua; Liang, Zhen; Zhang, Yukui

    2016-01-01

    We describe the synthesis of molecularly imprinted core-shell microparticles via a metal chelating strategy that assists in the creation of selective recognition sites for albumin. Porcine serum albumin (PSA) was immobilized on silica beads via copper(II) chelation interaction. A solution containing 2-hydroxyethyl methacrylate and methacrylic acid as the monomers was mixed with the above particles, and free radical polymerization was performed at 25 °C. Copper ion and template were then removed to obtain PSA-imprinted core-shell particles (MIPs) with a typical diameter of 5 μm. The binding capacity of such MIP was 8.9 mg protein per gram of MIPs, and the adsorption equilibrium was established within <20 min. The imprinting factor for PSA reached 2.6 when the binding capacity was 7.7 mg protein per gram of MIPs. The use of such MIPs enabled PSA to be selectively recognized even in presence of the competitive proteins ribonuclease B, cytochrome c, and myoglobin. The results indicate that this imprinting strategy for protein may become a promising method to prepare MIPs for protein recognition. (author)

  18. Gold nano particle decorated graphene core first generation PAMAM dendrimer for label free electrochemical DNA hybridization sensing.

    Science.gov (United States)

    Jayakumar, K; Rajesh, R; Dharuman, V; Venkatasan, R; Hahn, J H; Pandian, S Karutha

    2012-01-15

    A novel first generation (G1) poly(amidoamine) dendrimer (PAMAM) with graphene core (GG1PAMAM) was synthesized for the first time. Single layer of GG1PAMAM was immobilized covalently on mercaptopropionic acid (MPA) monolayer on Au transducer. This allows cost effective and easy deposition of single layer graphene on the Au transducer surface than the advanced vacuum techniques used in the literature. Au nano particles (17.5 nm) then decorated the GG1PAMAM and used for electrochemical DNA hybridization sensing. The sensor discriminates selectively and sensitively the complementary double stranded DNA (dsDNA, hybridized), non-complementary DNA (ssDNA, un-hybridized) and single nucleotide polymorphism (SNP) surfaces. Interactions of the MPA, GG1PAMAM and the Au nano particles were characterized by Ultra Violet (UV), Fourier Transform Infrared (FTIR), Raman spectroscopy (RS), Thermo gravimetric analysis (TGA), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Cyclic Voltmetric (CV), Impedance spectroscopy (IS) and Differntial Pulse Voltammetry (DPV) techniques. The sensor showed linear range 1×10(-6) to 1×10(-12) M with lowest detection limit 1 pM which is 1000 times lower than G1PAMAM without graphene core. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. Synthesis and electrochemical performance of surface-modified nano-sized core/shell tin particles for lithium ion batteries

    International Nuclear Information System (INIS)

    Schmuelling, Guido; Meyer, Hinrich-Wilhelm; Placke, Tobias; Winter, Martin; Oehl, Nikolas; Knipper, Martin; Kolny-Olesiak, Joanna; Plaggenborg, Thorsten; Parisi, Jürgen

    2014-01-01

    Tin is able to lithiate and delithiate reversibly with a high theoretical specific capacity, which makes it a promising candidate to supersede graphite as the state-of-the-art negative electrode material in lithium ion battery technology. Nevertheless, it still suffers from poor cycling stability and high irreversible capacities. In this contribution, we show the synthesis of three different nano-sized core/shell-type particles with crystalline tin cores and different amorphous surface shells consisting of SnO x and organic polymers. The spherical size and the surface shell can be tailored by adjusting the synthesis temperature and the polymer reagents in the synthesis, respectively. We determine the influence of the surface modifications with respect to the electrochemical performance and characterize the morphology, structure, and thermal properties of the nano-sized tin particles by means of high-resolution transmission electron microscopy, x-ray diffraction, and thermogravimetric analysis. The electrochemical performance is investigated by constant current charge/discharge cycling as well as cyclic voltammetry. (paper)

  20. Geraniin suppresses RANKL-induced osteoclastogenesis in vitro and ameliorates wear particle-induced osteolysis in mouse model

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Fei; Zhai, Zanjing; Jiang, Chuan; Liu, Xuqiang; Li, Haowei; Qu, Xinhua [Department of Orthopedics, Shanghai Key Laboratory of Orthopedic Implant, Shanghai Ninth People' s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Ouyang, Zhengxiao [Department of Orthopedics, Shanghai Key Laboratory of Orthopedic Implant, Shanghai Ninth People' s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Department of Orthopaedics, Hunan Provincial Tumor Hospital and Tumor Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013 (China); Fan, Qiming; Tang, Tingting [Department of Orthopedics, Shanghai Key Laboratory of Orthopedic Implant, Shanghai Ninth People' s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Qin, An, E-mail: dr.qinan@gmail.com [Department of Orthopedics, Shanghai Key Laboratory of Orthopedic Implant, Shanghai Ninth People' s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Gu, Dongyun, E-mail: dongyungu@gmail.com [Department of Orthopedics, Shanghai Key Laboratory of Orthopedic Implant, Shanghai Ninth People' s Hospital, Shanghai Jiaotong University School of Medicine, Shanghai (China); Engineering Research Center of Digital Medicine and Clinical Translation, Ministry of Education of PR China (China); School of Biomedical Engineering, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China)

    2015-01-01

    Wear particle-induced osteolysis and subsequent aseptic loosening remains the most common complication that limits the longevity of prostheses. Wear particle-induced osteoclastogenesis is known to be responsible for extensive bone erosion that leads to prosthesis failure. Thus, inhibition of osteoclastic bone resorption may serve as a therapeutic strategy for the treatment of wear particle induced osteolysis. In this study, we demonstrated for the first time that geraniin, an active natural compound derived from Geranium thunbergii, ameliorated particle-induced osteolysis in a Ti particle-induced mouse calvaria model in vivo. We also investigated the mechanism by which geraniin exerts inhibitory effects on osteoclasts. Geraniin inhibited RANKL-induced osteoclastogenesis in a dose-dependent manner, evidenced by reduced osteoclast formation and suppressed osteoclast specific gene expression. Specially, geraniin inhibited actin ring formation and bone resorption in vitro. Further molecular investigation demonstrated geraniin impaired osteoclast differentiation via the inhibition of the RANKL-induced NF-κB and ERK signaling pathways, as well as suppressed the expression of key osteoclast transcriptional factors NFATc1 and c-Fos. Collectively, our data suggested that geraniin exerts inhibitory effects on osteoclast differentiation in vitro and suppresses Ti particle-induced osteolysis in vivo. Geraniin is therefore a potential natural compound for the treatment of wear particle induced osteolysis in prostheses failure. - Highlights: • Geraniin suppresses osteoclasts formation and function in vitro. • Geraniin impairs RANKL-induced nuclear factor-κB and ERK signaling pathway. • Geraniin suppresses osteolysis in vivo. • Geraniin may be used for treating osteoclast related diseases.

  1. Synergistic effects in radiation-induced particle ejection from solid surfaces

    International Nuclear Information System (INIS)

    Itoh, Noriaki

    1990-01-01

    A description is given on radiation-induced particle ejection from solid surfaces, emphasizing synergistic effects arising from multi-species particle irradiation and from irradiation under complex environments. First, it is pointed out that synergisms can be treated by introducing the effects of material modification on radiation-induced particle ejection. As examples of the effects of surface modification on the sputtering induced by elastic encounters, sputtering of alloys and chemical sputtering of graphite are briefly discussed. Then the particle ejection induced by electronic encounters is explained emphasizing the difference in the behaviors from materials to materials. The possible synergistic effects of electronic and elastic encounters are also described. Lastly, we point out the importance of understanding the elementary processes of material-particle interaction and of developing computer codes describing material behaviors under irradiation. (author)

  2. Passing particle toroidal precession induced by electric field in a tokamak

    International Nuclear Information System (INIS)

    Andreev, V. V.; Ilgisonis, V. I.; Sorokina, E. A.

    2013-01-01

    Characteristics of a rotation of passing particles in a tokamak with radial electric field are calculated. The expression for time-averaged toroidal velocity of the passing particle induced by the electric field is derived. The electric-field-induced additive to the toroidal velocity of the passing particle appears to be much smaller than the velocity of the electric drift calculated for the poloidal magnetic field typical for the trapped particle. This quantity can even have the different sign depending on the azimuthal position of the particle starting point. The unified approach for the calculation of the bounce period and of the time-averaged toroidal velocity of both trapped and passing particles in the whole volume of plasma column is presented. The results are obtained analytically and are confirmed by 3D numerical calculations of the trajectories of charged particles

  3. Passing particle toroidal precession induced by electric field in a tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V. V. [Peoples' Friendship University of Russia, Ordzhonikidze St. 3, Moscow 117198 (Russian Federation); Ilgisonis, V. I.; Sorokina, E. A. [Peoples' Friendship University of Russia, Ordzhonikidze St. 3, Moscow 117198 (Russian Federation); NRC “Kurchatov Institute”, Kurchatov Sq. 1, Moscow 123182 (Russian Federation)

    2013-12-15

    Characteristics of a rotation of passing particles in a tokamak with radial electric field are calculated. The expression for time-averaged toroidal velocity of the passing particle induced by the electric field is derived. The electric-field-induced additive to the toroidal velocity of the passing particle appears to be much smaller than the velocity of the electric drift calculated for the poloidal magnetic field typical for the trapped particle. This quantity can even have the different sign depending on the azimuthal position of the particle starting point. The unified approach for the calculation of the bounce period and of the time-averaged toroidal velocity of both trapped and passing particles in the whole volume of plasma column is presented. The results are obtained analytically and are confirmed by 3D numerical calculations of the trajectories of charged particles.

  4. A Study on the Plasmonic Properties of Silver Core Gold Shell Nanoparticles: Optical Assessment of the Particle Structure

    Science.gov (United States)

    Mott, Derrick; Lee, JaeDong; Thi Bich Thuy, Nguyen; Aoki, Yoshiya; Singh, Prerna; Maenosono, Shinya

    2011-06-01

    This paper reports a qualitative comparison between the optical properties of a set of silver core, gold shell nanoparticles with varying composition and structure to those calculated using the Mie solution. To achieve this, silver nanoparticles were synthesized in aqueous phase from a silver hydroxide precursor with sodium acrylate as dual reducing-capping agent. The particles were then coated with a layer of gold with controllable thickness through a reduction-deposition process. The resulting nanoparticles reveal well defined optical properties that make them suitable for comparison to ideal calculated results using the Mie solution. The discussion focuses on the correlation between the synthesized core shell nanoparticles with varying Au shell thickness and the Mie solution results in terms of the optical properties. The results give insight in how to design and synthesize silver core, gold shell nanoparticles with controllable optical properties (e.g., SPR band in terms of intensity and position), and has implications in creating nanoparticle materials to be used as biological probes and sensing elements.

  5. Luminescence study of Eu3+ doped GdVO4 nanoparticles: Concentration, particle size, and core/shell effects

    Science.gov (United States)

    Singh, N. Shanta; Ningthoujam, R. S.; Devi, L. Romila; Yaiphaba, N.; Sudarsan, V.; Singh, S. Dorendrajit; Vatsa, R. K.; Tewari, R.

    2008-11-01

    Nanoparticles of GdVO4 doped with Eu3+ and core/shell of GdVO4:Eu3+/GdVO4 are prepared by urea hydrolysis method using ethylene glycol as capping agent as well as reaction medium at 130 °C. Unit cell volume increases when GdVO4 is doped with Eu3+ indicating the substitution of Gd3+ lattice sites by Eu3+. From luminescence study, it is confirmed that there is no particle size effect on emission positions of Eu3+. Optimum luminescence intensity is found to be in 5-10 at. % Eu3+. Above these concentrations, luminescence intensity decreases due to concentration quenching effect. There is an enhancement in luminescence intensity of core/shell nanoparticles. This has been attributed to the reduction in surface inhomogenities of Eu3+ surroundings by bonding to GdVO4 shell. The lifetime for D50 level increases with annealing and core/shell formation.

  6. Tandem fusion of hepatitis B core antigen allows assembly of virus-like particles in bacteria and plants with enhanced capacity to accommodate foreign proteins.

    Directory of Open Access Journals (Sweden)

    Hadrien Peyret

    Full Text Available The core protein of the hepatitis B virus, HBcAg, assembles into highly immunogenic virus-like particles (HBc VLPs when expressed in a variety of heterologous systems. Specifically, the major insertion region (MIR on the HBcAg protein allows the insertion of foreign sequences, which are then exposed on the tips of surface spike structures on the outside of the assembled particle. Here, we present a novel strategy which aids the display of whole proteins on the surface of HBc particles. This strategy, named tandem core, is based on the production of the HBcAg dimer as a single polypeptide chain by tandem fusion of two HBcAg open reading frames. This allows the insertion of large heterologous sequences in only one of the two MIRs in each spike, without compromising VLP formation. We present the use of tandem core technology in both plant and bacterial expression systems. The results show that tandem core particles can be produced with unmodified MIRs, or with one MIR in each tandem dimer modified to contain the entire sequence of GFP or of a camelid nanobody. Both inserted proteins are correctly folded and the nanobody fused to the surface of the tandem core particle (which we name tandibody retains the ability to bind to its cognate antigen. This technology paves the way for the display of natively folded proteins on the surface of HBc particles either through direct fusion or through non-covalent attachment via a nanobody.

  7. Aloe vera Induced Biomimetic Assemblage of Nucleobase into Nanosized Particles

    Science.gov (United States)

    Chauhan, Arun; Zubair, Swaleha; Sherwani, Asif; Owais, Mohammad

    2012-01-01

    Aim Biomimetic nano-assembly formation offers a convenient and bio friendly approach to fabricate complex structures from simple components with sub-nanometer precision. Recently, biomimetic (employing microorganism/plants) synthesis of metal and inorganic materials nano-particles has emerged as a simple and viable strategy. In the present study, we have extended biological synthesis of nano-particles to organic molecules, namely the anticancer agent 5-fluorouracil (5-FU), using Aloe vera leaf extract. Methodology The 5-FU nano- particles synthesized by using Aloe vera leaf extract were characterized by UV, FT-IR and fluorescence spectroscopic techniques. The size and shape of the synthesized nanoparticles were determined by TEM, while crystalline nature of 5-FU particles was established by X-ray diffraction study. The cytotoxic effects of 5-FU nanoparticles were assessed against HT-29 and Caco-2 (human adenocarcinoma colorectal) cell lines. Results Transmission electron microscopy and atomic force microscopic techniques confirmed nano-size of the synthesized particles. Importantly, the nano-assembled 5-FU retained its anticancer action against various cancerous cell lines. Conclusion In the present study, we have explored the potential of biomimetic synthesis of nanoparticles employing organic molecules with the hope that such developments will be helpful to introduce novel nano-particle formulations that will not only be more effective but would also be devoid of nano-particle associated putative toxicity constraints. PMID:22403622

  8. Particle trapping induced by the interplay between coherence and decoherence

    International Nuclear Information System (INIS)

    Yi Sangyong; Choi, Mahn-Soo; Kim, Sang Wook

    2009-01-01

    We propose a novel scheme to trap a particle based on a delicate interplay between coherence and decoherence. If the decoherence occurs as a particle is located in the scattering region and subsequently the appropriate destructive interference takes place, the particle can be trapped in the scattering area. We consider two possible experimental realizations of such trapping: a ring attached to a single lead and a ring attached to two leads. Our scheme has nothing to do with a quasi-bound state of the system, but has a close analogy with the weak localization phenomena in disordered conductors.

  9. Effect of particle-core-vibration coupling near the double closed $^{132}$Sn nucleus from precise magnetic moment measurements

    CERN Multimedia

    Postma, H; Heyde, K; Walker, P; Grant, I; Veskovic, M; Stone, N; Stone, J

    2002-01-01

    % IS301 \\\\ \\\\ Low temperature nuclear orientation of isotope-separator implanted short-lived radio-isotopes makes possible the measurements of nuclear magnetic dipole moments of oriented ground and excited states with half-lives longer than a few seconds. Coupling schemes characterizing the odd nucleons and ground-state deformations can be extracted from the nuclear moments. \\\\ We thus propose to measure the magnetic dipole moments of $^{127-133}$Sb to high precision using NMR/ON at the NICOLE facility. With (double magic +1) $^{133}$Sb as the reference, the main aim of this experiment is to examine whether the collective component in the 7/2$^+$ Sb ground state magnetic dipole moment varies as expected according to particle-core coupling calculations carried out for the Sb (Z=51) isotopes. Comparison of the 1-proton-particle excitations in Sb to 1-proton-hole states in In nuclei will shed light on differences between particle and hole excitations as understood within the present model. Comparison of ...

  10. Depletion-induced biaxial nematic states of boardlike particles

    International Nuclear Information System (INIS)

    Belli, S; Van Roij, R; Dijkstra, M

    2012-01-01

    With the aim of investigating the stability conditions of biaxial nematic liquid crystals, we study the effect of adding a non-adsorbing ideal depletant on the phase behavior of colloidal hard boardlike particles. We take into account the presence of the depletant by introducing an effective depletion attraction between a pair of boardlike particles. At fixed depletant fugacity, the stable liquid-crystal phase is determined through a mean-field theory with restricted orientations. Interestingly, we predict that for slightly elongated boardlike particles a critical depletant density exists, where the system undergoes a direct transition from an isotropic liquid to a biaxial nematic phase. As a consequence, by tuning the depletant density, an easy experimental control parameter, one can stabilize states of high biaxial nematic order even when these states are unstable for pure systems of boardlike particles. (paper)

  11. Aging induced changes on NEXAFS fingerprints in individual combustion particles

    Directory of Open Access Journals (Sweden)

    V. Zelenay

    2011-11-01

    Full Text Available Soot particles can significantly influence the Earth's climate by absorbing and scattering solar radiation as well as by acting as cloud condensation nuclei. However, despite their environmental (as well as economic and political importance, the way these properties are affected by atmospheric processing of the combustion exhaust gases is still a subject of discussion. In this work, individual soot particles emitted from two different vehicles, a EURO 2 transporter, a EURO 3 passenger car, and a wood stove were investigated on a single-particle basis. The emitted exhaust, including the particulate and the gas phase, was processed in a smog chamber with artificial solar radiation. Single particle specimens of both unprocessed and aged soot were characterized using near edge X-ray absorption fine structure spectroscopy (NEXAFS and scanning electron microscopy. Comparison of NEXAFS spectra from the unprocessed particles and those resulting from exhaust photooxidation in the chamber revealed changes in the carbon functional group content. For the wood stove emissions, these changes were minor, related to the relatively mild oxidation conditions. For the EURO 2 transporter emissions, the most apparent change was that of carboxylic carbon from oxidized organic compounds condensing on the primary soot particles. For the EURO 3 car emissions oxidation of primary soot particles upon photochemical aging has likely contributed as well. Overall, the changes in the NEXAFS fingerprints were in qualitative agreement with data from an aerosol mass spectrometer. Furthermore, by taking full advantage of our in situ microreactor concept, we show that the soot particles from all three combustion sources changed their ability to take up water under humid conditions upon photochemical aging of the exhaust. Due to the selectivity and sensitivity of the NEXAFS technique for the water mass, also small amounts of water taken up into the internal voids of agglomerated

  12. Alcohol Induced Hepatic Degeneration in a Hepatitis C Virus Core Protein Transgenic Mouse Model

    Directory of Open Access Journals (Sweden)

    Dong-Hyung Noh

    2014-03-01

    Full Text Available Hepatitis C virus (HCV has become a major public health issue. It is prevalent in most countries. HCV infection frequently begins without clinical symptoms, before progressing to persistent viremia, chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC in the majority of patients (70% to 80%. Alcohol is an independent cofactor that accelerates the development of HCC in chronic hepatitis C patients. The purpose of the current study was to evaluate ethanol-induced hepatic changes in HCV core-Tg mice and mutant core Tg mice. Wild type (NTG, core wild-Tg mice (TG-K, mutant core 116-Tg mice (TG-116 and mutant core 99-Tg mice (TG-99 were used in this investigation. All groups were given drinking water with 10% ethanol and 5% sucrose for 13 weeks. To observe liver morphological changes, we performed histopathological and immunohistochemical examinations. Histopathologically, NTG, TG-K and TG-116 mice showed moderate centrilobular necrosis, while severe centrilobular necrosis and hepatocyte dissociation were observed in TG-99 mice with increasing lymphocyte infiltration and piecemeal necrosis. In all groups, a small amount of collagen fiber was found, principally in portal areas. None of the mice were found to have myofibroblasts based on immunohistochemical staining specific for α-SMA. CYP2E1-positive cells were clearly detected in the centrilobular area in all groups. In the TG-99 mice, we also observed cells positive for CK8/18, TGF-β1 and phosphorylated (p-Smad2/3 and p21 around the necrotic hepatocytes in the centrilobular area (p < 0.01. Based on our data, alcohol intake induced piecemeal necrosis and hepatocyte dissociation in the TG-99 mice. These phenomena involved activation of the TGF-β1/p-Smad2/3/p21 signaling pathway in hepatocytes. Data from this study will be useful for elucidating the association between alcohol intake and HCV infection.

  13. Characterization of Inherent Particles and Mechanism of Thermal Stress Induced Particle Formation in HSV-2 Viral Vaccine Candidate.

    Science.gov (United States)

    Li, Lillian; Kirkitadze, Marina; Bhandal, Kamaljit; Roque, Cristopher; Yang, Eric; Carpick, Bruce; Rahman, Nausheen

    2017-11-10

    Vaccine formulations may contain visible and/or subvisible particles, which can vary in both size and morphology. Extrinsic particles, which are particles not part of the product such as foreign contaminants, are generally considered undesirable and should be eliminated or controlled in injectable products. However, biological products, in particular vaccines, may also contain particles that are inherent to the product. Here we focus on the characterization of visible and subvisible particles in a live, replication-deficient viral vaccine candidate against HSV genital herpes in an early developmental stage. HSV-2 viral vaccine was characterized using a panel of analytical methods, including Fourier transform infrared spectroscopy (FTIR), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Western blot, liquid chromatography-mass spectrometry (LC-MS), light microscopy, transmission electron microscopy (TEM), micro-flow imaging (MFI), dynamic light scattering (DLS), right angle light scattering (RALS), and intrinsic fluorescence. Particles in HSV-2 vaccine typically ranged from hundreds of nanometers to hundreds of micrometers in size and were determined to be inherent to the product. The infectious titer did not correlate with any trend in subvisible particle concentration and size distribution as shown by DLS, MFI, and TEM under stressed conditions. This suggested that particle changes in the submicron range were related to HSV-2 virion structure and had direct impact on biological activity. It was also observed that subvisible and visible particles could induce aggregation in the viral product. The temperature induced aggregation was observed by RALS, intrinsic fluorescence, and DLS. The increase of subvisible particle size with temperature could be fitted to a two-step thermokinetic model. Visible and subvisible particles were found to be inherent to the HSV-2 viral vaccine product. The mechanism of protein aggregation was discussed and a two

  14. Air bubble-induced detachment of polystyrene particles with different sizes from collector surfaces in a parallel plate flow chamber

    NARCIS (Netherlands)

    Gomez-Suarez, C; van der Mei, HC; Busscher, HJ

    2001-01-01

    Particle size was found to be an important factor in air bubble-induced detachment of colloidal particles from collector surfaces in a parallel plate flow chamber and generally polystyrene particles with a diameter of 806 nm detached less than particles with a diameter of 1400 nm. Particle

  15. Production of slow particle in 1.7 AGeV 84Kr induced emulsion interaction

    International Nuclear Information System (INIS)

    Li Huiling; Zhang Donghai; Li Xueqin; Jia Huiming

    2008-01-01

    The production of slow particle in 1.7 AGeV 84 Kr induced emulsion interaction was studied. The experimental results show that the average multiplicity of black, grey and heavily ionized track particle increases with the increase of impact centrality and target size. The average multiplicity of grey track particle and heavily ionized track particle increases with the increase of the number of black track particle. The average multiplicity of heavily ionized track particle increases with the increase of the number of grey track particle, but average multiplicity of black track particle increases with the increase of the number of grey track particle and then saturated. The average multiplicity of grey track particle increases with the increase of the number of heavily ionized track particle, but average multiplicity of black track particle increases with the increase of the number of heavily ionized track particle and then saturated. Those experimental results can be well explained by using the nuclear impact geometry model. (authors)

  16. Cross sections of nuclear reactions induced by protons, deuterons, and alpha particles. Pt.6. Phosphorus

    International Nuclear Information System (INIS)

    Tobailem, Jacques.

    1981-11-01

    Cross sections are reviewed for nuclear reactions induced by protons, deuterons, and alpha particles on phosphorus targets. When necessary, published experimental data are corrected, and, when possible, excitation functions are proposed [fr

  17. Characterization of nuclear physics targets using Rutherford backscattering and particle induced X-ray emission

    International Nuclear Information System (INIS)

    Rubehn, T.; Wozniak, G.J.; Phair, L.; Moretto, L.G.; Yu, K.M.

    1997-01-01

    Rutherford backscattering and particle induced X-ray emission have been utilized to precisely characterize targets used in nuclear fission experiments. The method allows for a fast and non-destructive determination of target thickness, homogeneity and element composition. (orig.)

  18. Calculation of the neutron noise induced by periodic deformations of a large sodium-cooled fast reactor core

    International Nuclear Information System (INIS)

    Zylbersztejn, F.; Tran, H.N.; Pazsit, I.; Filliatre, P.; Jammes, C.

    2014-01-01

    The subject of this paper is the calculation of the neutron noise induced by small-amplitude stationary radial variations of the core size (core expansion/compaction, also called core flowering) of a large sodium-cooled fast reactor. The calculations were performed on a realistic model of the European Sodium Fast Reactor (ESFR) core with a thermal output of 3600 MW(thermal), using a multigroup neutron noise simulator. The multigroup cross sections and their fluctuations that represent the core geometry changes for the neutron noise calculations were generated by the code ERANOS. The space and energy dependences of the noise source represented by the core expansion/compaction and the induced neutron noise are calculated and discussed. (authors)

  19. Averaged currents induced by alpha particles in an InSb compound semiconductor detector

    International Nuclear Information System (INIS)

    Kanno, Ikuo; Hishiki, Shigeomi; Kogetsu, Yoshitaka; Nakamura, Tatsuya; Katagiri, Masaki

    2008-01-01

    Very fast pulses due to alpha particle incidence were observed by an undoped-type InSb Schottky detector. This InSb detector was operated without applying bias voltage and its depletion layer thickness was less than the range of alpha particles. The averaged current induced by alpha particles was analyzed as a function of operating temperature and was shown to be proportional to the Hall mobility of InSb. (author)

  20. Radial diffusion of toroidally trapped particles induced by lower hybrid and fast waves

    International Nuclear Information System (INIS)

    Krlin, L.

    1992-10-01

    The interaction of RF field with toroidally trapped particles (bananas) can cause their intrinsic stochastically diffusion both in the configuration and velocity space. In RF heating and/or current drive regimes, RF field can interact with plasma particles and with thermonuclear alpha particles. The aim of this contribution is to give some analytical estimates of induced radial diffusion of alphas and of ions. (author)

  1. Mapping the particle acceleration in the cool core of the galaxy cluster RX J1720.1+2638

    International Nuclear Information System (INIS)

    Giacintucci, S.; Markevitch, M.; Brunetti, G.; Venturi, T.; ZuHone, J. A.; Mazzotta, P.; Bourdin, H.

    2014-01-01

    We present new deep, high-resolution radio images of the diffuse minihalo in the cool core of the galaxy cluster RX J1720.1+2638. The images have been obtained with the Giant Metrewave Radio Telescope at 317, 617, and 1280 MHz and with the Very Large Array at 1.5, 4.9, and 8.4 GHz, with angular resolutions ranging from 1'' to 10''. This represents the best radio spectral and imaging data set for any minihalo. Most of the radio flux of the minihalo arises from a bright central component with a maximum radius of ∼80 kpc. A fainter tail of emission extends out from the central component to form a spiral-shaped structure with a length of ∼230 kpc, seen at frequencies 1.5 GHz and below. We find indication of a possible steepening of the total radio spectrum of the minihalo at high frequencies. Furthermore, a spectral index image shows that the spectrum of the diffuse emission steepens with increasing distance along the tail. A striking spatial correlation is observed between the minihalo emission and two cold fronts visible in the Chandra X-ray image of this cool core. These cold fronts confine the minihalo, as also seen in numerical simulations of minihalo formation by sloshing-induced turbulence. All these observations favor the hypothesis that the radio-emitting electrons in cluster cool cores are produced by turbulent re-acceleration.

  2. DRIFT-INDUCED PERPENDICULAR TRANSPORT OF SOLAR ENERGETIC PARTICLES

    International Nuclear Information System (INIS)

    Marsh, M. S.; Dalla, S.; Kelly, J.; Laitinen, T.

    2013-01-01

    Drifts are known to play a role in galactic cosmic ray transport within the heliosphere and are a standard component of cosmic ray propagation models. However, the current paradigm of solar energetic particle (SEP) propagation holds the effects of drifts to be negligible, and they are not accounted for in most current SEP modeling efforts. We present full-orbit test particle simulations of SEP propagation in a Parker spiral interplanetary magnetic field (IMF), which demonstrate that high-energy particle drifts cause significant asymmetric propagation perpendicular to the IMF. Thus in many cases the assumption of field-aligned propagation of SEPs may not be valid. We show that SEP drifts have dependencies on energy, heliographic latitude, and charge-to-mass ratio that are capable of transporting energetic particles perpendicular to the field over significant distances within interplanetary space, e.g., protons of initial energy 100 MeV propagate distances across the field on the order of 1 AU, over timescales typical of a gradual SEP event. Our results demonstrate the need for current models of SEP events to include the effects of particle drift. We show that the drift is considerably stronger for heavy ion SEPs due to their larger mass-to-charge ratio. This paradigm shift has important consequences for the modeling of SEP events and is crucial to the understanding and interpretation of in situ observations

  3. Preparing poly (caprolactone) micro-particles through solvent-induced phase separation

    DEFF Research Database (Denmark)

    Li, Xiaoqiang; Kanjwal, Muzafar Ahmed; Stephansen, Karen

    2012-01-01

    Poly (caprolactone) (PCL) particles with the size distribution from 1 to 100 μm were prepared through solvent-induced phase separation, in which polyvinyl-alcohol (PVA) was used as the matrix-forming polymer to stabilize PCL particles. The cloud point data of PCL-acetone-water was determined...

  4. The rotationally induced quadrupole pair field in the particle-rotor model

    International Nuclear Information System (INIS)

    Almberger, J.

    1980-04-01

    A formalism is developed which makes it possible to consider the influence of the rotationally induced quadrupole pair field and corresponding quasi-particle residual interactions within the particle-rotor model. The Y 21 pair field renormalizes both the Coriolis and the recoil interactions. (Auth.)

  5. Erratum: Erratum to: Thermodynamic implications of the gravitationally induced particle creation scenario

    Science.gov (United States)

    Saha, Subhajit; Mondal, Anindita

    2018-04-01

    We would like to rectify an error regarding the validity of the first law of thermodynamics (FLT) on the apparent horizon of a spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) universe for the gravitationally induced particle creation scenario with constant specific entropy and an arbitrary particle creation rate (see Sect. 3.1 of original article)

  6. Density functional formulation of the random-phase approximation for inhomogeneous fluids: Application to the Gaussian core and Coulomb particles.

    Science.gov (United States)

    Frydel, Derek; Ma, Manman

    2016-06-01

    Using the adiabatic connection, we formulate the free energy in terms of the correlation function of a fictitious system, h_{λ}(r,r^{'}), in which interactions λu(r,r^{'}) are gradually switched on as λ changes from 0 to 1. The function h_{λ}(r,r^{'}) is then obtained from the inhomogeneous Ornstein-Zernike equation and the two equations constitute a general liquid-state framework for treating inhomogeneous fluids. The two equations do not yet constitute a closed set. In the present work we use the closure c_{λ}(r,r^{'})≈-λβu(r,r^{'}), known as the random-phase approximation (RPA). We demonstrate that the RPA is identical with the variational Gaussian approximation derived within the field-theoretical framework, originally derived and used for charged particles. We apply our generalized RPA approximation to the Gaussian core model and Coulomb charges.

  7. Nano-magnetic particles used in biomedicine: core and coating materials.

    Science.gov (United States)

    Karimi, Z; Karimi, L; Shokrollahi, H

    2013-07-01

    Magnetic nanoparticles for medical applications have been developed by many researchers. Separation, immunoassay, drug delivery, magnetic resonance imaging and hyperthermia are enhanced by the use of suitable magnetic nanoparticles and coating materials in the form of ferrofluids. Due to their low biocompatibility and low dispersion in water solutions, nanoparticles that are used for biomedical applications require surface treatment. Various kinds of coating materials including organic materials (polymers), inorganic metals (gold, platinum) or metal oxides (aluminum oxide, cobalt oxide) have been attracted during the last few years. Based on the recent advances and the importance of nanomedicine in human life, this paper attempts to give a brief summary on the different ferrite nano-magnetic particles and coatings used in nanomedicine. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Optimization of laser-induced breakdown spectroscopy for coal powder analysis with different particle flow diameters

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Shunchun, E-mail: epscyao@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); State Key Laboratory of Pulsed Power Laser Technology, Electronic Engineering Institute, Hefei 230037 (China); Xu, Jialong; Dong, Xuan; Zhang, Bo; Zheng, Jianping [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Lu, Jidong, E-mail: jdlu@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China)

    2015-08-01

    The on-line measurement of coal is extremely useful for emission control and combustion process optimization in coal-fired plant. Laser-induced breakdown spectroscopy was employed to directly analyze coal particle flow. A set of tapered tubes were proposed for beam-focusing the coal particle flow to different diameters. For optimizing the measurement of coal particle flow, the characteristics of laser-induced plasma, including optical breakdown, the relative standard deviation of repeated measurement, partial breakdown spectra ratio and line intensity, were carefully analyzed. The comparison of the plasma characteristics among coal particle flow with different diameters showed that air breakdown and the random change in plasma position relative to the collection optics could significantly influence on the line intensity and the reproducibility of measurement. It is demonstrated that the tapered tube with a diameter of 5.5 mm was particularly useful to enrich the coal particles in laser focus spot as well as to reduce the influence of air breakdown and random changes of plasma in the experiment. - Highlights: • Tapered tube was designed for beam-focusing the coal particle flow as well as enriching the particles in laser focus spot. • The characteristics of laser-induced plasma of coal particle flow were investigated carefully. • An appropriate diameter of coal particle flow was proven to benefit for improving the performance of LIBS measurement.

  9. Ion-induced nucleation of pure biogenic particles

    CERN Document Server

    Kirkby, Jasper; Sengupta, Kamalika; Frege, Carla; Gordon, Hamish; Williamson, Christina; Heinritzi, Martin; Simon, Mario; Yan, Chao; Almeida, João; Tröstl, Jasmin; Nieminen, Tuomo; Ortega, Ismael K; Wagner, Robert; Adamov, Alexey; Amorim, Antonio; Bernhammer, Anne-Kathrin; Bianchi, Federico; Breitenlechner, Martin; Brilke, Sophia; Chen, Xuemeng; Craven, Jill; Dias, antonio; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Fuchs, Claudia; Guida, Roberto; Hakala, Jani; Hoyle, Christopher R; Jokinen, Tuija; Junninen, Heikki; Kangasluoma, Juha; Kim, Jaeseok; Krapf, Manuel; Kürten, andreas; Laaksonen, Ari; Lehtipalo, Katrianne; Makhmutov, Vladimir; Mathot, Serge; Molteni, Ugo; Onnela, antti; Peräkylä, Otso; Piel, Felix; Petäjä, Tuukka; Praplan, Arnaud P; Pringle, Kirsty; Rap, Alexandru; Richards, Nigel A D; Riipinen, Ilona; Rissanen, Matti P; Rondo, Linda; Sarnela, Nina; Schobesberger, Siegfried; Scott, Catherine E; Seinfeld, John H; Sipilä, Mikko; Steiner, Gerhard; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Virtanen, Annele; Vogel, Alexander L; Wagner, Andrea C; Wagner, Paul E; Weingartner, Ernest; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Zhang, Xuan; Hansel, Armin; Dommen, Josef; Donahue, Neil M; Worsnop, Douglas R; Baltensperger, Urs; Kulmala, Markku; Carslaw, Kenneth S; Curtius, Joachim

    2016-01-01

    Atmospheric aerosols and their effect on clouds are thought to be important for anthropogenic radiative forcing of the climate, yet remain poorly understood. Globally, around half of cloud condensation nuclei originate from nucleation of atmospheric vapours. It is thought that sulfuric acid is essential to initiate most particle formation in the atmosphere and that ions have a relatively minor role. Some laboratory studies, however, have reported organic particle formation without the intentional addition of sulfuric acid, although contamination could not be excluded. Here we present evidence for the formation of aerosol particles from highly oxidized biogenic vapours in the absence of sulfuric acid in a large chamber under atmospheric conditions. The highly oxygenated molecules (HOMs) are produced by ozonolysis of $\\alpha$-pinene. We find that ions from Galactic cosmic rays increase the nucleation rate by one to two orders of magnitude compared with neutral nucleation. Our experimental findings are supported...

  10. Labeling the oily core of nanocapsules and lipid-core nanocapsules with a triglyceride conjugated to a fluorescent dye as a strategy to particle tracking in biological studies

    Science.gov (United States)

    Fiel, Luana Almeida; Contri, Renata Vidor; Bica, Juliane Freitas; Figueiró, Fabrício; Battastini, Ana Maria Oliveira; Guterres, Sílvia Stanisçuaski; Pohlmann, Adriana Raffin

    2014-05-01

    The synthesis of novel fluorescent materials represents a very important step to obtain labeled nanoformulations in order to evaluate their biological behavior. The strategy of conjugating a fluorescent dye with triacylglycerol allows that either particles differing regarding supramolecular structure, i.e., nanoemulsions, nanocapsules, lipid-core nanocapsules, or surface charge, i.e., cationic nanocapsules and anionic nanocapsules, can be tracked using the same labeled material. In this way, a rhodamine B-conjugated triglyceride was obtained to prepare fluorescent polymeric nanocapsules. Different formulations were obtained, nanocapsules (NC) or lipid-core nanocapsules (LNC), using the labeled oil and Eudragit RS100, Eudragit S100, or poly(caprolactone) (PCL), respectively. The rhodamine B was coupled with the ricinolein by activating the carboxylic function using a carbodiimide derivative. Thin layer chromatography, proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FTIR), UV-vis, and fluorescence spectroscopy were used to identify the new product. Fluorescent nanocapsule aqueous suspensions were prepared by the solvent displacement method. Their pH values were 4.6 (NC-RS100), 3.5 (NC-S100), and 5.0 (LNC-PCL). The volume-weighted mean diameter ( D 4.3) and polydispersity values were 150 nm and 1.05 (NC-RS100), 350 nm and 2.28 (NC-S100), and 270 nm and 1.67 (LNC-PCL). The mean diameters determined by photon correlation spectroscopy (PCS) ( z-average) were around 200 nm. The zeta potential values were +5.85 mV (NC-RS100), -21.12 mV (NC-S100), and -19.25 mV (LNC-PCL). The wavelengths of maximum fluorescence emission were 567 nm (NC-RS100 and LNC-PCL) and 574 nm (NC-S100). Fluorescence microscopy was used to evaluate the cell uptake (human macrophage cell line) of the fluorescent nanocapsules in order to show the applicability of the approach. When the cells were treated with the fluorescent nanocapsules, red emission was detected

  11. NMR relaxation induced by iron oxide particles: testing theoretical models.

    Science.gov (United States)

    Gossuin, Y; Orlando, T; Basini, M; Henrard, D; Lascialfari, A; Mattea, C; Stapf, S; Vuong, Q L

    2016-04-15

    Superparamagnetic iron oxide particles find their main application as contrast agents for cellular and molecular magnetic resonance imaging. The contrast they bring is due to the shortening of the transverse relaxation time T 2 of water protons. In order to understand their influence on proton relaxation, different theoretical relaxation models have been developed, each of them presenting a certain validity domain, which depends on the particle characteristics and proton dynamics. The validation of these models is crucial since they allow for predicting the ideal particle characteristics for obtaining the best contrast but also because the fitting of T 1 experimental data by the theory constitutes an interesting tool for the characterization of the nanoparticles. In this work, T 2 of suspensions of iron oxide particles in different solvents and at different temperatures, corresponding to different proton diffusion properties, were measured and were compared to the three main theoretical models (the motional averaging regime, the static dephasing regime, and the partial refocusing model) with good qualitative agreement. However, a real quantitative agreement was not observed, probably because of the complexity of these nanoparticulate systems. The Roch theory, developed in the motional averaging regime (MAR), was also successfully used to fit T 1 nuclear magnetic relaxation dispersion (NMRD) profiles, even outside the MAR validity range, and provided a good estimate of the particle size. On the other hand, the simultaneous fitting of T 1 and T 2 NMRD profiles by the theory was impossible, and this occurrence constitutes a clear limitation of the Roch model. Finally, the theory was shown to satisfactorily fit the deuterium T 1 NMRD profile of superparamagnetic particle suspensions in heavy water.

  12. [Adsorption of Cu on Core-shell Structured Magnetic Particles: Relationship Between Adsorption Performance and Surface Properties].

    Science.gov (United States)

    Li, Qiu-mei; Chen, Jing; Li, Hai-ning; Zhang, Xiao-lei; Zhang, Gao-sheng

    2015-12-01

    In order to reveal the relationship between the adsorption performance of adsorbents and their compositions, structure, and surface properties, the core-shell structured Fe₃O₄/MnO2 and Fe-Mn/Mn₂2 magnetic particles were systematically characterized using multiple techniques and their Cu adsorption behaviors as well as mechanism were also investigated in details. It was found that both Fe₃O4 and Fe-Mn had spinel structure and no obvious crystalline phase change was observed after coating with MnO₂. The introduction of Mn might improve the affinity between the core and the shell, and therefore enhanced the amount and distribution uniformity of the MnO₂ coated. Consequently, Fe-Mn/MnO₂ exhibited a higher BET specific surface area and a lower isoelectric point. The results of sorption experiments showed that Fe-Mn had a higher maximal Cu adsorption capacity of 33.7 mg · g⁻¹ at pH 5.5, compared with 17.5 mg · g⁻¹ of Fe₃O4. After coating, the maximal adsorption capacity of Fe-Mn/MnO₂ was increased to 58.2 mg · g⁻¹, which was 2.6 times as high as that of Fe₃O₄/MnO₂ and outperformed the majority of magnetic adsorbents reported in literature. In addition, a specific adsorption of Cu occurred at the surface of Fe₃O₄/MnO₂ or Fe-Mn/MnO₂ through the formation of inner-sphere complexes. In conclusion, the adsorption performance of the magnetic particles was positively related to their compositions, structure, and surface properties.

  13. Coupling-induced cooperative behaviour in dynamic ferromagnetic cores in the presence of a noise floor

    International Nuclear Information System (INIS)

    Bulsara, Adi R.; Lindner, John F.; In, Visarath; Kho, Andy; Baglio, Salvatore; Sacco, Vincenzo; Ando, Bruno; Longhini, Patrick; Palacios, Antonio; Rappel, Wouter-Jan

    2006-01-01

    Recently, we have shown the emergence of oscillations in overdamped undriven nonlinear dynamic systems subject to carefully crafted coupling schemes and operating conditions. Here, we summarize experimental results obtained on a system of N=3 coupled ferromagnetic cores, the underpinning of a 'coupled-core fluxgate magnetometer' (CCFM); the oscillatory behaviour is triggered when the coupling constant exceeds a threshold value (bifurcation point), and the oscillation frequency exhibits a characteristic scaling behaviour with the 'separation' of the coupling constant from its threshold value, as well as with an external target DC magnetic flux signal. The oscillations, which can be induced at frequencies ranging from a few Hz to high-kHz, afford a new detection scheme for weak target magnetic signals. We also present the first (numerical) results on the effects of a (Gaussian, exponentially correlated) noise floor on the spectral properties of the system response

  14. Coupling-induced cooperative behaviour in dynamic ferromagnetic cores in the presence of a noise floor

    Energy Technology Data Exchange (ETDEWEB)

    Bulsara, Adi R. [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States)]. E-mail: bulsara@spawar.navy.mil; Lindner, John F. [Physics Department, College of Wooster, Wooster, OH 44691 (United States); In, Visarath [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States); Kho, Andy [Space and Naval Warfare Systems Center San Diego, Code 2363, 53560 Hull Street, San Diego, CA 92152-5001 (United States); Baglio, Salvatore [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Sacco, Vincenzo [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Ando, Bruno [Dipartimento di Ingegneria Elettrica Elettronica e dei Sistemi, Universita degli Studi di Catania, Viale A. Doria 6, 95125 Catania (Italy); Longhini, Patrick [Nonlinear Dynamics Group, Department of Mathematics, San Diego State University, San Diego, CA 92182 (United States); Palacios, Antonio [Nonlinear Dynamics Group, Department of Mathematics, San Diego State University, San Diego, CA 92182 (United States); Rappel, Wouter-Jan [Physics Department, University of California at San Diego, La Jolla, CA 929093 (United States)

    2006-04-17

    Recently, we have shown the emergence of oscillations in overdamped undriven nonlinear dynamic systems subject to carefully crafted coupling schemes and operating conditions. Here, we summarize experimental results obtained on a system of N=3 coupled ferromagnetic cores, the underpinning of a 'coupled-core fluxgate magnetometer' (CCFM); the oscillatory behaviour is triggered when the coupling constant exceeds a threshold value (bifurcation point), and the oscillation frequency exhibits a characteristic scaling behaviour with the 'separation' of the coupling constant from its threshold value, as well as with an external target DC magnetic flux signal. The oscillations, which can be induced at frequencies ranging from a few Hz to high-kHz, afford a new detection scheme for weak target magnetic signals. We also present the first (numerical) results on the effects of a (Gaussian, exponentially correlated) noise floor on the spectral properties of the system response.

  15. Drilling induced damage of core samples. Evidences from laboratory testing and numerical modelling

    International Nuclear Information System (INIS)

    Lanaro, Flavio

    2008-01-01

    Extensive sample testing in uniaxial and Brazilian test conditions were carried out for the Shobasama and MIU Research Laboratory Site (Gifu Pref., Japan). The compressive and tensile strength of the samples was observed to be negatively correlated to the in-situ stress components. Such correlation was interpreted as stress-release induced sample damage. Similar stress conditions were then numerically simulated by means of the BEM-DDM code FRACOD 2D in plane strain conditions. This method allows for explicitly consider the influence of newly initiated or propagating fractures on the stress field and deformation of the core during drilling process. The models show that already at moderate stress levels some fracturing of the core during drilling might occur leading to reduced laboratory strength of the samples. Sample damage maps were produced independently from the laboratory test results and from the numerical models and show good agreement with each other. (author)

  16. Core Cross-Linked Multiarm Star Polymers with Aggregation-Induced Emission and Temperature Responsive Fluorescence Characteristics

    KAUST Repository

    Zhang, Zhen; Bilalis, Panagiotis; Zhang, Hefeng; Gnanou, Yves; Hadjichristidis, Nikolaos

    2017-01-01

    Aggregation-induced emission (AIE) active core cross-linked multiarm star polymers, carrying polystyrene (PS), polyethylene (PE), or polyethylene-b-polycaprolactone (PE-b-PCL) arms, have been synthesized through an “arm-first” strategy, by atom

  17. Measurement of secondary particle production induced by particle therapy ion beams impinging on a PMMA target

    Directory of Open Access Journals (Sweden)

    Toppi M.

    2016-01-01

    Full Text Available Particle therapy is a technique that uses accelerated charged ions for cancer treatment and combines a high irradiation precision with a high biological effectiveness in killing tumor cells [1]. Informations about the secondary particles emitted in the interaction of an ion beam with the patient during a treatment can be of great interest in order to monitor the dose deposition. For this purpose an experiment at the HIT (Heidelberg Ion-Beam Therapy Center beam facility has been performed in order to measure fluxes and emission profiles of secondary particles produced in the interaction of therapeutic beams with a PMMA target. In this contribution some preliminary results about the emission profiles and the energy spectra of the detected secondaries will be presented.

  18. Transcription Factors Encoded on Core and Accessory Chromosomes of Fusarium oxysporum Induce Expression of Effector Genes

    Science.gov (United States)

    van der Does, H. Charlotte; Schmidt, Sarah M.; Langereis, Léon; Hughes, Timothy R.

    2016-01-01

    Proteins secreted by pathogens during host colonization largely determine the outcome of pathogen-host interactions and are commonly called ‘effectors’. In fungal plant pathogens, coordinated transcriptional up-regulation of effector genes is a key feature of pathogenesis and effectors are often encoded in genomic regions with distinct repeat content, histone code and rate of evolution. In the tomato pathogen Fusarium oxysporum f. sp. lycopersici (Fol), effector genes reside on one of four accessory chromosomes, known as the ‘pathogenicity’ chromosome, which can be exchanged between strains through horizontal transfer. The three other accessory chromosomes in the Fol reference strain may also be important for virulence towards tomato. Expression of effector genes in Fol is highly up-regulated upon infection and requires Sge1, a transcription factor encoded on the core genome. Interestingly, the pathogenicity chromosome itself contains 13 predicted transcription factor genes and for all except one, there is a homolog on the core genome. We determined DNA binding specificity for nine transcription factors using oligonucleotide arrays. The binding sites for homologous transcription factors were highly similar, suggesting that extensive neofunctionalization of DNA binding specificity has not occurred. Several DNA binding sites are enriched on accessory chromosomes, and expression of FTF1, its core homolog FTF2 and SGE1 from a constitutive promoter can induce expression of effector genes. The DNA binding sites of only these three transcription factors are enriched among genes up-regulated during infection. We further show that Ftf1, Ftf2 and Sge1 can activate transcription from their binding sites in yeast. RNAseq analysis revealed that in strains with constitutive expression of FTF1, FTF2 or SGE1, expression of a similar set of plant-responsive genes on the pathogenicity chromosome is induced, including most effector genes. We conclude that the Fol

  19. Structures of SRP54 and SRP19, the two proteins that organize the ribonucleic core of the signal recognition particle from Pyrococcus furiosus.

    Directory of Open Access Journals (Sweden)

    Pascal F Egea

    Full Text Available In all organisms the Signal Recognition Particle (SRP, binds to signal sequences of proteins destined for secretion or membrane insertion as they emerge from translating ribosomes. In Archaea and Eucarya, the conserved ribonucleoproteic core is composed of two proteins, the accessory protein SRP19, the essential GTPase SRP54, and an evolutionarily conserved and essential SRP RNA. Through the GTP-dependent interaction between the SRP and its cognate receptor SR, ribosomes harboring nascent polypeptidic chains destined for secretion are dynamically transferred to the protein translocation apparatus at the membrane. We present here high-resolution X-ray structures of SRP54 and SRP19, the two RNA binding components forming the core of the signal recognition particle from the hyper-thermophilic archaeon Pyrococcus furiosus (Pfu. The 2.5 A resolution structure of free Pfu-SRP54 is the first showing the complete domain organization of a GDP bound full-length SRP54 subunit. In its ras-like GTPase domain, GDP is found tightly associated with the protein. The flexible linker that separates the GTPase core from the hydrophobic signal sequence binding M domain, adopts a purely alpha-helical structure and acts as an articulated arm allowing the M domain to explore multiple regions as it scans for signal peptides as they emerge from the ribosomal tunnel. This linker is structurally coupled to the GTPase catalytic site and likely to propagate conformational changes occurring in the M domain through the SRP RNA upon signal sequence binding. Two different 1.8 A resolution crystal structures of free Pfu-SRP19 reveal a compact, rigid and well-folded protein even in absence of its obligate SRP RNA partner. Comparison with other SRP19*SRP RNA structures suggests the rearrangement of a disordered loop upon binding with the RNA through a reciprocal induced-fit mechanism and supports the idea that SRP19 acts as a molecular scaffold and a chaperone, assisting the SRP

  20. Study of the liquid water luminescence induced by charged particles

    International Nuclear Information System (INIS)

    Rusu, Mircea; Stere, Oana; Haiduc, Maria; Caramete, Laurentiu

    2004-01-01

    Many observations suggested that liquid water (with impurities) could give a luminescence output when irradiated with charged particles. We investigate theoretical and practical possibility of detecting such luminescence. Preliminary results on this possibility are presented, and a layout of the device proposed for measuring luminescence is given. (authors)

  1. Preparation by alkaline treatment and detailed characterisation of empty hepatitis B virus core particles for vaccine and gene therapy applications

    Science.gov (United States)

    Strods, Arnis; Ose, Velta; Bogans, Janis; Cielens, Indulis; Kalnins, Gints; Radovica, Ilze; Kazaks, Andris; Pumpens, Paul; Renhofa, Regina

    2015-06-01

    Hepatitis B virus (HBV) core (HBc) virus-like particles (VLPs) are one of the most powerful protein engineering tools utilised to expose immunological epitopes and/or cell-targeting signals and for the packaging of genetic material and immune stimulatory sequences. Although HBc VLPs and their numerous derivatives are produced in highly efficient bacterial and yeast expression systems, the existing purification and packaging protocols are not sufficiently optimised and standardised. Here, a simple alkaline treatment method was employed for the complete removal of internal RNA from bacteria- and yeast-produced HBc VLPs and for the conversion of these VLPs into empty particles, without any damage to the VLP structure. The empty HBc VLPs were able to effectively package the added DNA and RNA sequences. Furthermore, the alkaline hydrolysis technology appeared efficient for the purification and packaging of four different HBc variants carrying lysine residues on the HBc VLP spikes. Utilising the introduced lysine residues and the intrinsic aspartic and glutamic acid residues exposed on the tips of the HBc spikes for chemical coupling of the chosen peptide and/or nucleic acid sequences ensured a standard and easy protocol for the further development of versatile HBc VLP-based vaccine and gene therapy applications.

  2. Antiviral Activity of Gold/Copper Sulfide Core/Shell Nanoparticles against Human Norovirus Virus-Like Particles.

    Directory of Open Access Journals (Sweden)

    Jessica Jenkins Broglie

    Full Text Available Human norovirus is a leading cause of acute gastroenteritis worldwide in a plethora of residential and commercial settings, including restaurants, schools, and hospitals. Methods for easily detecting the virus and for treating and preventing infection are critical to stopping norovirus outbreaks, and inactivation via nanoparticles (NPs is a more universal and attractive alternative to other physical and chemical approaches. Using norovirus GI.1 (Norwalk virus-like particles (VLPs as a model viral system, this study characterized the antiviral activity of Au/CuS core/shell nanoparticles (NPs against GI.1 VLPs for the rapid inactivation of HuNoV. Inactivation of VLPs (GI.1 by Au/CuS NPs evaluated using an absorbance-based ELISA indicated that treatment with 0.083 μM NPs for 10 min inactivated ~50% VLPs in a 0.37 μg/ml VLP solution and 0.83 μM NPs for 10 min completely inactivated the VLPs. Increasing nanoparticle concentration and/or VLP-NP contact time significantly increased the virucidal efficacy of Au/CuS NPs. Changes to the VLP particle morphology, size, and capsid protein were characterized using dynamic light scattering, transmission electron microscopy, and Western blot analysis. The strategy reported here provides the first reported proof-of-concept Au/CuS NPs-based virucide for rapidly inactivating human norovirus.

  3. Charge neutralization as the major factor for the assembly of nucleocapsid-like particles from C-terminal truncated hepatitis C virus core protein

    OpenAIRE

    Theo Luiz Ferraz de Souza; Sheila Maria Barbosa de Lima; Vanessa L. de Azevedo Braga; David S. Peabody; Davis Fernandes Ferreira; M. Lucia Bianconi; Andre Marco de Oliveira Gomes; Jerson Lima Silva; Andréa Cheble de Oliveira

    2016-01-01

    Background Hepatitis C virus (HCV) core protein, in addition to its structural role to form the nucleocapsid assembly, plays a critical role in HCV pathogenesis by interfering in several cellular processes, including microRNA and mRNA homeostasis. The C-terminal truncated HCV core protein (C124) is intrinsically unstructured in solution and is able to interact with unspecific nucleic acids, in the micromolar range, and to assemble into nucleocapsid-like particles (NLPs) in vitro. The specific...

  4. Tumor necrosis factor is not required for particle-induced genotoxicity and pulmonary inflammation

    Energy Technology Data Exchange (ETDEWEB)

    Saber, Anne T.; Bornholdt, Jette; Dybdahl, Marianne; Sharma, Anoop K.; Vogel, Ulla; Wallin, Haakan [National Institute of Occupational Health, Copenhagen (Denmark); Loft, Steffen [Copenhagen University, Institute of Public Health, Copenhagen (Denmark)

    2005-03-01

    Particle-induced carcinogenicity is not well understood, but might involve inflammation. The proinflammatory cytokine tumor necrosis factor (TNF) is considered to be an important mediator in inflammation. We investigated its role in particle-induced inflammation and DNA damage in mice with and without TNF signaling. TNF-/- mice and TNF+/+ mice were exposed by inhalation to 20 mg m{sup -3} carbon black (CB), 20 mg m{sup -3} diesel exhaust particles (DEP), or filtered air for 90 min on each of four consecutive days. DEP, but not CB particles, induced infiltration of neutrophilic granulocutes into the lung lining fluid (by the cellular fraction in the bronchoalveolar lavage fluid), and both particle types induced interleukin-6 mRNA in the lung tissue. Surprisingly, TNF-/- mice were intact in these inflammatory responses. There were more DNA strand breaks in the BAL cells of DEP-exposed TNF-/- mice and CB-exposed mice compared with the air-exposed mice. Thus, the CB-induced DNA damage in BAL-cells was independent of neutrophil infiltration. The data indicate that an inflammatory response was not a prerequisite for DNA damage, and TNF was not required for the induction of inflammation by DEP and CB particles. (orig.)

  5. Analysis of propeller-induced ground vortices by particle image velocimetry

    NARCIS (Netherlands)

    Yang, Y.; Sciacchitano, A.; Veldhuis, L.L.M.; Eitelberg, G.

    2017-01-01

    Abstract: The interaction between a propeller and its self-induced vortices originating on the ground is investigated in a scaled experiment. The velocity distribution in the flow field in two different planes containing the self-induced vortices is measured by particle image velocimetry (PIV).

  6. Effect of particle size on laser-induced breakdown spectroscopy analysis of alumina suspension in liquids

    International Nuclear Information System (INIS)

    Diaz Rosado, José Carlos; L'hermite, Daniel; Levi, Yves

    2012-01-01

    The analysis by Laser Induced Breakdown Spectroscopy (LIBS) was proposed for the detection and the quantification of different elements in water even when the analyte is composed of particles in suspension. We have studied the effect of particle size on the LIBS signal during liquid analysis. In our study we used different particle sizes (from 2 μm to 90 μm) of Al 2 O 3 in suspension in water. The results were compared to the signal obtained in the case of dissolved aluminum. In the case of particles, a linear correlation between the LIBS signal versus concentration was found but a significant decrease in the slope of the calibration curve was found when the particle size increased. Several hypotheses have been tested and only a partial ablation of the particles might explain this decrease in signal intensity. This effect probably does not occur at smaller particle size. We estimated 860 nm/pulse as ablated thickness from the top of the particle. A statistical analysis over all data obtained allowed us to calculate 100 μm as ablated water column depth. - Highlights: ► We have identified a decrease of calibration curve when particle size increases. ► Partial particle ablation has been identified as the origin of this effect. ► The ablation rate on Al 2 O 3 particles in suspension in water has been estimated. ► We can determine the deepness of the interaction volume into the liquid.

  7. Particle roughness in magnetorheology: effect on the strength of the field-induced structures

    International Nuclear Information System (INIS)

    Vereda, F; Segovia-Gutiérrez, J P; De Vicente, J; Hidalgo-Alvarez, R

    2015-01-01

    We report a study on the effect of particle roughness on the strength of the field-induced structures of magnetorheological (MR) fluids in the quasi-static regime. We prepared one set of MR fluids with carbonyl iron particles and another set with magnetite particles, and in both sets we had particles with different degrees of surface roughness. Small amplitude oscillatory shear (SAOS) magnetosweeps and steady shear (SS) tests were carried out on the suspensions to measure their elastic modulus (G′) and static yield stress (τ static ). Results for both the iron and the magnetite sets of suspensions were consistent: for the MR fluids prepared with rougher particles, G′ increased at smaller fields and τ static was ca. 20% larger than for the suspensions prepared with relatively smooth particles. In addition to the experimental study, we carried out finite element method calculations to assess the effect of particle roughness on the magnetic interaction between particles. These calculations showed that roughness can facilitate the magnetization of the particles, thus increasing the magnetic energy of the system for a given field, but that this effect depends on the concrete morphology of the surface. For our real systems, no major differences were observed between the magnetization cycles of the MR fluids prepared with particles with different degree of roughness, which implied that the effect of roughness on the measured G′ and τ static was due mainly to friction between the solid surfaces of adjacent particles. (paper)

  8. Nonlinear mechanisms for drift wave saturation and induced particle transport

    International Nuclear Information System (INIS)

    Dimits, A.M.; Lee, W.W.

    1989-12-01

    A detailed theoretical study of the nonlinear dynamics of gyrokinetic particle simulations of electrostatic collisionless and weakly collisional drift waves is presented. In previous studies it was shown that, in the nonlinearly saturated phase of the evolution, the saturation levels and especially the particle fluxes have an unexpected dependence on collisionality. In this paper, the explanations for these collisionality dependences are found to be as follows: The saturation level is determined by a balance between the electron and ion fluxes. The ion flux is small for levels of the potential below an E x B-trapping threshold and increases sharply once this threshold is crossed. Due to the presence of resonant electrons, the electron flux has a much smoother dependence on the potential. In the 2-1/2-dimensional (''pseudo-3D'') geometry, the electrons are accelerated away from the resonance as they diffuse spatially, resulting in an inhibition of their diffusion. Collisions and three-dimensional effects can repopulate the resonance thereby increasing the value of the particle flux. 30 refs., 32 figs., 2 tabs

  9. Different particle determinants induce apoptosis and cytokine release in primary alveolar macrophage cultures

    Directory of Open Access Journals (Sweden)

    Schwarze Per E

    2006-06-01

    Full Text Available Abstract Background Particles are known to induce both cytokine release (MIP-2, TNF-α, a reduction in cell viability and an increased apoptosis in alveolar macrophages. To examine whether these responses are triggered by the same particle determinants, alveolar macrophages were exposed in vitro to mineral particles of different physical-chemical properties. Results The crystalline particles of the different stone types mylonite, gabbro, basalt, feldspar, quartz, hornfels and fine grain syenite porphyr (porphyr, with a relatively equal size distribution (≤ 10 μm, but different chemical/mineral composition, all induced low and relatively similar levels of apoptosis. In contrast, mylonite and gabbro induced a marked MIP-2 response compared to the other particles. For particles of smaller size, quartz (≤ 2 μm seemed to induce a somewhat stronger apoptotic response than even smaller quartz (≤ 0.5 μm and larger quartz (≤ 10 μm in relation to surface area, and was more potent than hornfels and porphyr (≤ 2 μm. The reduction in cell viability induced by quartz of the different sizes was roughly similar when adjusted to surface area. With respect to cytokines, the release was more marked after exposure to quartz ≤ 0.5 μm than to quartz ≤ 2 μm and ≤ 10 μm. Furthermore, hornfels (≤ 2 μm was more potent than the corresponding hornfels (≤ 10 μm and quartz (≤ 2 μm to induce cytokine responses. Pre-treatment of hornfels and quartz particles ≤ 2 μm with aluminium lactate, to diminish the surface reactivity, did significantly reduce the MIP-2 response to hornfels. In contrast, the apoptotic responses to the particles were not affected. Conclusion These results indicate that different determinants of mineral/stone particles are critical for inducing cytokine responses, reduction in cell viability and apoptosis in alveolar macrophages. The data suggest that the particle surface reactivity was critical for cytokine responses

  10. Necrosis of HepG2 cancer cells induced by the vibration of magnetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Biran [Laboratoire de Physique de la Matière Condensée (LPMC), CNRS UMR 7336, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice (France); Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, 28 Avenue de Valrose, F-06100 Nice (France); Bienvenu, Céline [Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, 28 Avenue de Valrose, F-06100 Nice (France); Mendez-Garza, Juan; Lançon, Pascal; Madeira, Alexandra [Laboratoire de Physique de la Matière Condensée (LPMC), CNRS UMR 7336, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice (France); Vierling, Pierre [Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, 28 Avenue de Valrose, F-06100 Nice (France); Di Giorgio, Christophe, E-mail: christophe.di-giorgio@unice.fr [Institut de Chimie de Nice, UMR 7272, Université de Nice Sophia Antipolis, CNRS, 28 Avenue de Valrose, F-06100 Nice (France); Bossis, Georges, E-mail: bossis@unice.fr [Laboratoire de Physique de la Matière Condensée (LPMC), CNRS UMR 7336, Université de Nice Sophia Antipolis, Parc Valrose, 06108 Nice (France)

    2013-10-15

    Experiments of magnetolysis, i.e., destruction of cells induced with magnetic particles (MPs) submitted to the application of a magnetic field, were conducted on HepG2 cancer cells. We herein demonstrate the usefulness of combining anisotropic MPs with an alternative magnetic field in magnetolysis. Thus, the application of an alternative magnetic field of low frequency (a few Hertz) in the presence of anisotropic, submicronic particles allowed the destruction of cancer cells “in vitro”. We also show that a constant magnetic field is far less efficient than an oscillating one. Moreover, we demonstrate that, at equal particle volume, it is much more efficient to utilize spindle shaped particles rather than spherical ones. In order to get deeper insight into the mechanism of magnetolysis experiments, we performed a study by AFM, which strongly supports that the magnetic field induces the formation of clusters of particles becoming then large enough todamage cell membranes. - Highlights: • Magnetic force was applied on cancer cells through magnetic particles. • The penetration depth was predicted, both for spherical and ellipsoidal particles. • Alternative force was shown to damage the cells contrary to static force. • The effect of indentation of magnetic particles was compared to the one of AFM tips. • The damage was attributed to the formation of clusters of particles.

  11. The effects of particle size distribution and induced unpinning during grain growth

    International Nuclear Information System (INIS)

    Thompson, G.S.; Rickman, J.M.; Harmer, M.P.; Holm, E.A.

    1996-01-01

    The effect of a second-phase particle size distribution on grain boundary pinning was studied using a Monte Carlo simulation technique. Simulations were run using a constant number density of both whisker and rhombohedral particles, and the effect of size distribution was studied by varying the standard deviation of the distribution around a constant mean particle size. The results of present simulations indicate that, in accordance with the stereological assumption of the topological pinning model, changes in distribution width had no effect on the pinned grain size. The effect of induced unpinning of particles on microstructure was also studied. In contrast to predictions of the topological pinning model, a power law dependence of pinned grain size on particle size was observed at T=0.0. Based on this, a systematic deviation to the stereological predictions of the topological pinning model is observed. The results of simulations at higher temperatures indicate an increasing power law dependence of pinned grain size on particle size, with the slopes of the power law dependencies fitting an Arrhenius relation. The effect of induced unpinning of particles was also studied in order to obtain a correlation between particle/boundary concentration and equilibrium grain size. The results of simulations containing a constant number density of monosized rhombohedral particles suggest a strong power law correlation between the two parameters. copyright 1996 Materials Research Society

  12. Solar Particle Induced Upsets in the TDRS-1 Attitude Control System RAM During the October 1989 Solar Particle Events

    Science.gov (United States)

    Croley, D. R.; Garrett, H. B.; Murphy, G. B.; Garrard,T. L.

    1995-01-01

    The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAM unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo, designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEU's calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEU's by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEU'S. The proton fluence spectrum at the device level was gotten by transporting the protons through the estimated shielding distribution. The number of calculated proton-induced SEU's was 72, yielding a total of 248 predicted SEU'S, very dose to the 243 observed SEU'S. These calculations uniquely demonstrate the roles that solar heavy ions and protons played in the production of SEU

  13. Silica nanoparticles as the adjuvant for the immunisation of mice using hepatitis B core virus-like particles.

    Directory of Open Access Journals (Sweden)

    Dace Skrastina

    Full Text Available Advances in nanotechnology and nanomaterials have facilitated the development of silicon dioxide, or Silica, particles as a promising immunological adjuvant for the generation of novel prophylactic and therapeutic vaccines. In the present study, we have compared the adjuvanting potential of commercially available Silica nanoparticles (initial particles size of 10-20 nm with that of aluminium hydroxide, or Alum, as well as that of complete and incomplete Freund's adjuvants for the immunisation of BALB/c mice with virus-like particles (VLPs formed by recombinant full-length Hepatitis B virus core (HBc protein. The induction of B-cell and T-cell responses was studied after immunisation. Silica nanoparticles were able to adsorb maximally 40% of the added HBc, whereas the adsorption capacity of Alum exceeded 90% at the same VLPs/adjuvant ratio. Both Silica and Alum formed large complexes with HBc VLPs that sedimented rapidly after formulation, as detected by dynamic light scattering, spectrophotometry, and electron microscopy. Both Silica and Alum augmented the humoral response against HBc VLPs to the high anti-HBc level in the case of intraperitoneal immunisation, whereas in subcutaneous immunisation, the Silica-adjuvanted anti-HBc level even exceeded the level adjuvanted by Alum. The adjuvanting of HBc VLPs by Silica resulted in the same typical IgG2a/IgG1 ratios as in the case of the adjuvanting by Alum. The combination of Silica with monophosphoryl lipid A (MPL led to the same enhancement of the HBc-specific T-cell induction as in the case of the Alum and MPL combination. These findings demonstrate that Silica is not a weaker putative adjuvant than Alum for induction of B-cell and T-cell responses against recombinant HBc VLPs. This finding may have an essential impact on the development of the set of Silica-adjuvanted vaccines based on a long list of HBc-derived virus-like particles as the biological component.

  14. Isocratic and gradient impedance plot analysis and comparison of some recently introduced large size core-shell and fully porous particles.

    Science.gov (United States)

    Vanderheyden, Yoachim; Cabooter, Deirdre; Desmet, Gert; Broeckhoven, Ken

    2013-10-18

    The intrinsic kinetic performance of three recently commercialized large size (≥4μm) core-shell particles packed in columns with different lengths has been measured and compared with that of standard fully porous particles of similar and smaller size (5 and 3.5μm, respectively). The kinetic performance is compared in both absolute (plot of t0 versus the plate count N or the peak capacity np for isocratic and gradient elution, respectively) and dimensionless units. The latter is realized by switching to so-called impedance plots, a format which has been previously introduced (as a plot of t0/N(2) or E0 versus Nopt/N) and has in the present study been extended from isocratic to gradient elution (where the impedance plot corresponds to a plot of t0/np(4) versus np,opt(2)/np(2)). Both the isocratic and gradient impedance plot yielded a very similar picture: the clustered impedance plot curves divide into two distinct groups, one for the core-shell particles (lowest values, i.e. best performance) and one for the fully porous particles (highest values), confirming the clear intrinsic kinetic advantage of core-shell particles. If used around their optimal flow rate, the core-shell particles displayed a minimal separation impedance that is about 40% lower than the fully porous particles. Even larger gains in separation speed can be achieved in the C-term regime. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Incorporation of deoxyribonucleotides and ribonucleotides by a dNTP-binding cleft mutated reverse transcriptase in hepatitis B virus core particles

    International Nuclear Information System (INIS)

    Kim, Hee-Young; Kim, Hye-Young; Jung, Jaesung; Park, Sun; Shin, Ho-Joon; Kim, Kyongmin

    2008-01-01

    Our recent observation that hepatitis B virus (HBV) DNA polymerase (P) might initiate minus-strand DNA synthesis without primer [Kim et al., (2004) Virology 322, 22-30], raised a possibility that HBV P protein may have the potential to function as an RNA polymerase. Thus, we mutated Phe 436, a bulky amino acid with aromatic side chain, at the putative dNTP-binding cleft in reverse transcriptase (RT) domain of P protein to smaller amino acids (Gly or Val), and examined RNA polymerase activity. HBV core particles containing RT dNTP-binding cleft mutant P protein were able to incorporate 32 P-ribonucleotides, but not HBV core particles containing wild type (wt), priming-deficient mutant, or RT-deficient mutant P proteins. Since all the experiments were conducted with core particles isolated from transfected cells, our results indicate that the HBV RT mutant core particles containing RT dNTP-binding cleft mutant P protein could incorporate both deoxyribonucleotides and ribonucleotides in replicating systems

  16. Particle-induced amorphization of complex ceramics. Final report

    International Nuclear Information System (INIS)

    Ewing, R.C.; Wang, L.M.

    1998-01-01

    The crystalline-to-amorphous (c-a) phase transition is of fundamental importance. Particle irradiations provide an important, highly controlled means of investigating this phase transformation and the structure of the amorphous state. The interaction of heavy-particles with ceramics is complex because these materials have a wide range of structure types, complex compositions, and because chemical bonding is variable. Radiation damage and annealing can produce diverse results, but most commonly, single crystals become aperiodic or break down into a polycrystalline aggregate. The authors continued the studies of the transition from the periodic-to-aperiodic state in natural materials that have been damaged by α-recoil nuclei in the uranium and thorium decay series and in synthetic, analogous structures. The transition from the periodic to aperiodic state was followed by detailed x-ray diffraction analysis, in-situ irradiation/transmission electron microscopy, high resolution transmission electron microscopy, extended x-ray absorption fine structure spectroscopy/x-ray absorption near edge spectroscopy and other spectroscopic techniques. These studies were completed in conjunction with bulk irradiations that can be completed at Los Alamos National Laboratory or Sandia National Laboratories. Principal questions addressed in this research program included: (1) What is the process at the atomic level by which a ceramic material is transformed into a disordered or aperiodic state? (2) What are the controlling effects of structural topology, bond-type, dose rate, and irradiation temperature on the final state of the irradiated material? (3) What is the structure of the damaged material? (4) What are the mechanisms and kinetics for the annealing of interstitial and aggregate defects in these irradiated ceramic materials? (5) What general criteria may be applied to the prediction of amorphization in complex ceramics?

  17. Stopping power and polarization induced in a plasma by a fast charged particle in circular motion

    Energy Technology Data Exchange (ETDEWEB)

    Villo-Perez, Isidro [Departamento de Electronica, Tecnologia de las Computadoras y Proyectos, Universidad Politecnica de Cartagena, Cartagena (Spain); Arista, Nestor R. [Division Colisiones Atomicas, Centro Atomico Bariloche and Instituto Balseiro, Comision Nacional de Energia Atomica, Bariloche (Argentina); Garcia-Molina, Rafael [Departamento de Fisica, Universidad de Murcia, Murcia (Spain)

    2002-03-28

    We describe the perturbation induced in a plasma by a charged particle in circular motion, analysing in detail the evolution of the induced charge, the electrostatic potential and the energy loss of the particle. We describe the initial transitory behaviour and the different ways in which convergence to final stationary solutions may be obtained depending on the basic parameters of the problem. The results for the stopping power show a resonant behaviour which may give place to large stopping enhancement values as compared with the case of particles in straight-line motion with the same linear velocity. The results also explain a resonant effect recently obtained for particles in circular motion in magnetized plasmas. (author)

  18. Solar particle induced upsets in the TDRS-1 attitude control system RAM during the October 1989 solar particle events

    International Nuclear Information System (INIS)

    Croley, D.R.; Garrett, H.B.; Murphy, G.B.; Garrard, T.L.

    1995-01-01

    The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAM unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo, designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEU's calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEU's by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEU's. The proton fluence spectrum at the device level was gotten by transporting the protons through the estimated shielding distribution. The number of calculated proton-induced SEU's was 72, yielding a total of 248 predicted SEU's, very close to the 243 observed SEU's

  19. In vitro assembly into virus-like particles is an intrinsic quality of Pichia pastoris derived HCV core protein

    International Nuclear Information System (INIS)

    Acosta-Rivero, Nelson; Rodriguez, Armando; Musacchio, Alexis; Falcon, Viviana; Suarez, Viana M.; Martinez, Gillian; Guerra, Ivis; Paz-Lago, Dalila; Morera, Yanelys; Rosa, Maria C. de la; Morales-Grillo, Juan; Duenas-Carrera, Santiago

    2004-01-01

    Different variants of hepatitis C virus core protein (HCcAg) have proved to self-assemble in vitro into virus-like particles (VLPs). However, difficulties in obtaining purified mature HCcAg have limited these studies. In this study, a high degree of monomeric HCcAg purification was accomplished using chromatographic procedures under denaturing conditions. Size exclusion chromatography and sucrose density gradient centrifugation of renatured HCcAg (in the absence of structured RNA) under reducing conditions suggested that it assembled into empty capsids. The electron microscopy analysis of renatured HCcAg showed the presence of spherical VLPs with irregular shapes and an average diameter of 35 nm. Data indicated that HCcAg monomers assembled in vitro into VLPs in the absence of structured RNA, suggesting that recombinant HCcAg used in this work contains all the information necessary for the assembly process. However, they also suggest that some cellular factors might be required for the proper in vitro assembly of capsids

  20. Flash X-ray measurements on the shock-induced dispersal of a dense particle curtain

    Science.gov (United States)

    Wagner, Justin L.; Kearney, Sean P.; Beresh, Steven J.; DeMauro, Edward P.; Pruett, Brian O.

    2015-12-01

    The interaction of a Mach 1.67 shock wave with a dense particle curtain is quantified using flash radiography. These new data provide a view of particle transport inside a compressible, dense gas-solid flow of high optical opacity. The curtain, composed of 115-µm glass spheres, initially spans 87 % of the test section width and has a streamwise thickness of about 2 mm. Radiograph intensities are converted to particle volume fraction distributions using the Beer-Lambert law. The mass in the particle curtain, as determined from the X-ray data, is in reasonable agreement with that given from a simpler method using a load cell and particle imaging. Following shock impingement, the curtain propagates downstream and the peak volume fraction decreases from about 23 to about 4 % over a time of 340 µs. The propagation occurs asymmetrically, with the downstream side of the particle curtain experiencing a greater volume fraction gradient than the upstream side, attributable to the dependence of particle drag on volume fraction. Bulk particle transport is quantified from the time-dependent center of mass of the curtain. The bulk acceleration of the curtain is shown to be greater than that predicted for a single 115-µm particle in a Mach 1.67 shock-induced flow.

  1. Prediction of lung cells oncogenic transformation for induced radon progeny alpha particles using sugarscape cellular automata.

    Science.gov (United States)

    Baradaran, Samaneh; Maleknasr, Niaz; Setayeshi, Saeed; Akbari, Mohammad Esmaeil

    2014-01-01

    Alpha particle irradiation from radon progeny is one of the major natural sources of effective dose in the public population. Oncogenic transformation is a biological effectiveness of radon progeny alpha particle hits. The biological effects which has caused by exposure to radon, were the main result of a complex series of physical, chemical, biological and physiological interactions. The cellular and molecular mechanisms for radon-induced carcinogenesis have not been clear yet. Various biological models, including cultured cells and animals, have been found useful for studying the carcinogenesis effects of radon progeny alpha particles. In this paper, sugars cape cellular automata have been presented for computational study of complex biological effect of radon progeny alpha particles in lung bronchial airways. The model has included mechanism of DNA damage, which has been induced alpha particles hits, and then formation of transformation in the lung cells. Biomarkers were an objective measure or evaluation of normal or abnormal biological processes. In the model, the metabolism rate of infected cell has been induced alpha particles traversals, as a biomarker, has been followed to reach oncogenic transformation. The model results have successfully validated in comparison with "in vitro oncogenic transformation data" for C3H 10T1/2 cells. This model has provided an opportunity to study the cellular and molecular changes, at the various stages in radiation carcinogenesis, involving human cells. It has become well known that simulation could be used to investigate complex biomedical systems, in situations where traditional methodologies were difficult or too costly to employ.

  2. light charged particles induced nuclear reaction on some medium weight nuclei for particles applications

    International Nuclear Information System (INIS)

    Mohsena, B.M.A.M.

    2011-01-01

    The radioisotopes of indium, cadmium and tin have many practical and medical applications. Their standard routes for production are proton or deuteron induced reactions on natural or enriched cadmium or tin. The production via 3 He induced reactions on natural or enriched cadmium was rarely discussed. In this study 3 He induced reactions on natural cadmium were measured utilizing the stacked-foil technique. The primary incident beam energy was 27 MeV extracted from the MGC- 20E cyclotron, Debrecen, Hungary.the exciatation functions for the reactions n atCd( 3 He,x) 115g,111m Cd, 117m,g,116m,115m,114m,113m,111g,110m,g,109g,108g,107g In and 117m,113,111,110 Sn were evaluated. The data were compared with the available literature data.Different theoretical nuclear reaction models were also used to predict the cross sections for those reactions. The used models were ALICE-IPPE, TALYS-1.2 and EMPIRE-03. The experimental data were compared also to the theoretical model calculations. The theoretical models did not describe most of the experimental results.The isomeric cross section ratios for the isomeric pairs 117m,g In and 110m,g In were calculated. The isomeric cross section ratio depends on the spins of the states of the interested isomeric pair. The calculated isomeric ratios helped to identify the mechanisms of the reactions involved.The integral yields for some medically relevant isotopes were calculated using the excitation function curves

  3. Investigation of the production of slow particles in 60 A GeV 16O induced nuclear emulsion reaction

    International Nuclear Information System (INIS)

    Zhang Donghai

    2001-01-01

    The multiplicity distributions and correlations of grey track producing particles (N g ), black track producing particles (N b ) and heavy track producing particles (N h ) have been studied in 60 A GeV 16 O induced nuclear emulsion reaction. The multiplicity distributions of grey particles, black particles and heavy track producing particles can be reproduced by FRITIOF (version 1.7) taking cascade mechanism in to account and DTUNUC2.0 with an incident energy of 200 A GeV. The mean multiplicity of black particles (N b ) increases with the number of grey particle N g up to 10 and then exhibits a saturation for peripheral, central and mini-bias events; the average values of grey particles g > (heavy track producing particles h > increase with increasing values of black particle N b (grey particle N g )

  4. Diffusion induced nuclear reactions in metals: a possible source of heat in the core

    International Nuclear Information System (INIS)

    Hamza, V.M.; Iyer, S.S.S.

    1989-01-01

    It has recently been proposed that diffusion of light nuclei in metals can give rise to unusual electrical charge distributions in their lattice structures, inducing thereby certain nuclear reactions that are otherwise uncommon. In the light of these results we advance the hypothesis that such nuclear reactions take place in the metal rich core of the earth, based on following observations: 1 - The solubility of hydrogen in metals is relatively high compared to that in silicates. 2 - Studies of rare gas samples in intraplate volcanos and diamonds show that 3 He/ He ratio increases with depth in the mantle. 3 - There are indications that He is positively correlated with enrichment of metals in lavas. We propose that hydrogen incorporated into metallic phases at the time of planetary accretion was carried to the core by downward migration of metal rich melts during the early states of proto-earth. Preliminary estimates suggest that cold fusion reactions can give rise to an average rate of heat generation of 8.2x10 12 W and may thus serve as a supplementary source of energy for the geomagnetic dynamo. (author)

  5. BEND-INDUCED LOSSES IN A SINGLE-MODE MICROSTRUCTURED FIBER WITH A LARGE CORE

    Directory of Open Access Journals (Sweden)

    Y. A. Gatchin

    2015-03-01

    Full Text Available A study of bend-induced losses in a silica-based single-mode microstructured fiber with a core diameter ranging from 20 to 35 microns and increased relative air content in the holey cladding has been conducted. With the use of the equivalent step-index profile method in approximation of waveguide parameters of microstructured fiber (normalized frequency and normalized transverse attenuation constant the effect of bending on the spectral position of the fundamentalmode short-wavelength leakage boundary has been analyzed. Upon measurement of spectral characteristics of attenuation in the considered fibers good accordance of numerical and experimental data has been found out. It is shown that increase of the air content in the holey cladding leads to expansion of the mentioned boundary to lower wavelengths for the value from 150 to 800 nm depending on the core size and bending conditions. A single-transverse-mode propagation is achieved on fiber length of 5-10 meters due to a substantial difference in losses of fundamental and higher-order guided modes attained by bending. Optical losses in all studied samples are less than 10 dB/km at the wavelength λ = 1550 nm. The results of the study can be applied in the design of high-power laser systems having such basic requirements as a relatively large mode spot and high beam quality.

  6. Waveguides fabricated by femtosecond laser exploiting both depressed cladding and stress-induced guiding core.

    Science.gov (United States)

    Dong, Ming-Ming; Wang, Cheng-Wei; Wu, Zheng-Xiang; Zhang, Yang; Pan, Huai-Hai; Zhao, Quan-Zhong

    2013-07-01

    We report on the fabrication of stress-induced optical channel waveguides and waveguide splitters with laser-depressed cladding by femtosecond laser. The laser beam was focused into neodymium doped phosphate glass by an objective producing a destructive filament. By moving the sample along an enclosed routine in the horizontal plane followed by a minor descent less than the filament length in the vertical direction, a cylinder with rarified periphery and densified center region was fabricated. Lining up the segments in partially overlapping sequence enabled waveguiding therein. The refractive-index contrast, near- and far-field mode distribution and confocal microscope fluorescence image of the waveguide were obtained. 1-to-2, 1-to-3 and 1-to-4 splitters were also machined with adjustable splitting ratio. Compared with traditional femtosecond laser writing methods, waveguides prepared by this approach showed controllable mode conduction, strong field confinement, large numerical aperture, low propagation loss and intact core region.

  7. Core/Shell Microstructure Induced Synergistic Effect for Efficient Water-Droplet Formation and Cloud-Seeding Application.

    Science.gov (United States)

    Tai, Yanlong; Liang, Haoran; Zaki, Abdelali; El Hadri, Nabil; Abshaev, Ali M; Huchunaev, Buzgigit M; Griffiths, Steve; Jouiad, Mustapha; Zou, Linda

    2017-12-26

    Cloud-seeding materials as a promising water-augmentation technology have drawn more attention recently. We designed and synthesized a type of core/shell NaCl/TiO 2 (CSNT) particle with controlled particle size, which successfully adsorbed more water vapor (∼295 times at low relative humidity, 20% RH) than that of pure NaCl, deliquesced at a lower environmental RH of 62-66% than the hygroscopic point (h g.p ., 75% RH) of NaCl, and formed larger water droplets ∼6-10 times its original measured size area, whereas the pure NaCl still remained as a crystal at the same conditions. The enhanced performance was attributed to the synergistic effect of the hydrophilic TiO 2 shell and hygroscopic NaCl core microstructure, which attracted a large amount of water vapor and turned it into a liquid faster. Moreover, the critical particle size of the CSNT particles (0.4-10 μm) as cloud-seeding materials was predicted via the classical Kelvin equation based on their surface hydrophilicity. Finally, the benefits of CSNT particles for cloud-seeding applications were determined visually through in situ observation under an environmental scanning electron microscope on the microscale and cloud chamber experiments on the macroscale, respectively. These excellent and consistent performances positively confirmed that CSNT particles could be promising cloud-seeding materials.

  8. Harnessing the advantages of hard and soft colloids by the use of core-shell particles as interfacial stabilizers

    NARCIS (Netherlands)

    Buchcic, C.; Tromp, R.H.; Meinders, M.B.J.; Cohen Stuart, M.A.

    2017-01-01

    The ability of colloidal particles to penetrate fluid interfaces is a crucial factor in the preparation of particle stabilized disperse systems such as foams and emulsions. For hard micron-sized particles the insertion into fluid interfaces requires substantial energy input, but soft particles

  9. Multi-core events in cosmic-ray induced interactions with lead at around 10 TeV

    International Nuclear Information System (INIS)

    Amato, N.; Arata, N.

    1989-01-01

    The analysis is made on the cosmic-ray induced interactions with lead at around 10 TeV on the basis of emulsion chamber data at Chacaltaya. A special attention is paid to the events detected as multi-cores under the spatial resolution of a few tens of microns. The observation of six double-core events and two triple-core events with the average invariant mass of 1.8 GeV/c 2 leads to the estimation on production frequency of such multicores as about 5% at 10 TeV at the atmospheric depth 540 gr/cm 2 . (author)

  10. Field-induced optically isotropic state in bent core nematic liquid crystals: unambiguous proof of field-induced optical biaxiality

    International Nuclear Information System (INIS)

    Elamain, Omaima; Komitov, Lachezar; Hegde, Gurumurthy; Fodor-Csorba, Katalin

    2013-01-01

    The behaviour of bent core (BC) nematic liquid crystals was investigated under dc applied electric field. The optically isotropic state of a sample containing BC nematic was observed under application of low dc electric fields. The quality of the dark state when the sample was inserted between two crossed polarizers was found to be superb and it did not change when rotating the sample between the polarizers. The coupling between the net molecular dipole moment and the applied dc electric field was considered as the origin of the out-of-plane switching of the BC molecules resulting in switching from the field-off bright state to the field-on dark state. The field-induced optically isotropic state is an unambiguous proof of the field-induced biaxiality in the BC nematic liquid crystal. A simple model explaining the appearance of the isotropic optical state in BC nematics and the switching of the sample slow axis between three mutually orthogonal directions under dc applied electric field is proposed. (paper)

  11. Effect of particle size on laser-induced breakdown spectroscopy analysis of alumina suspension in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Rosado, Jose Carlos [CEA, DEN, SEARS, LANIE, 91191 Gif-sur-Yvette (France); Univ. Paris Sud, Faculty of Pharmaceutical Sciences, Public Health and Environment UMR 8079, 5 rue J.B. Clement, 92296 Chatenay-Malabry (France); National University of Engineering, Faculty of Science, P.O. Box 31-139, Av. Tupac Amaru 210, Lima (Peru); L' hermite, Daniel, E-mail: daniel.lhermite@cea.fr [CEA, DEN, SEARS, LANIE, 91191 Gif-sur-Yvette (France); Levi, Yves [Univ. Paris Sud, Faculty of Pharmaceutical Sciences, Public Health and Environment UMR 8079, 5 rue J.B. Clement, 92296 Chatenay-Malabry (France)

    2012-08-15

    The analysis by Laser Induced Breakdown Spectroscopy (LIBS) was proposed for the detection and the quantification of different elements in water even when the analyte is composed of particles in suspension. We have studied the effect of particle size on the LIBS signal during liquid analysis. In our study we used different particle sizes (from 2 {mu}m to 90 {mu}m) of Al{sub 2}O{sub 3} in suspension in water. The results were compared to the signal obtained in the case of dissolved aluminum. In the case of particles, a linear correlation between the LIBS signal versus concentration was found but a significant decrease in the slope of the calibration curve was found when the particle size increased. Several hypotheses have been tested and only a partial ablation of the particles might explain this decrease in signal intensity. This effect probably does not occur at smaller particle size. We estimated 860 nm/pulse as ablated thickness from the top of the particle. A statistical analysis over all data obtained allowed us to calculate 100 {mu}m as ablated water column depth. - Highlights: Black-Right-Pointing-Pointer We have identified a decrease of calibration curve when particle size increases. Black-Right-Pointing-Pointer Partial particle ablation has been identified as the origin of this effect. Black-Right-Pointing-Pointer The ablation rate on Al{sub 2}O{sub 3} particles in suspension in water has been estimated. Black-Right-Pointing-Pointer We can determine the deepness of the interaction volume into the liquid.

  12. Human hepatocytes apoptosis induced by replication of hepatitis B virus subgenotypes F1b and F4: Role of basal core promoter and preCore mutations.

    Science.gov (United States)

    Elizalde, María Mercedes; Sevic, Ina; González López Ledesma, María Mora; Campos, Rodolfo Héctor; Barbini, Luciana; Flichman, Diego Martin

    2018-01-01

    In the context of pathogenesis of HBV infection, HBV genotypes and mutants have been shown to affect the natural course of chronic infection and treatment outcomes. In this work, we studied the induction of apoptosis by the replication of HBV subgenotypes F1b and F4, and the naturally occurring mutants BCP and preCore. Both subgenotypes F1b and F4 HBV genome transfections induced cell death by apoptosis in human hepatocytes. The BCPdm (A1762T/G1764A) and preCore (G1896A) mutants induced higher levels of apoptosis than the wt virus. This increase in apoptosis was not associated with the enhanced viral replication of the variants. HBV-mediated apoptosis was independent of viral subgenotypes, and associated with the modulation of members of the regulatory Bcl-2 family proteins expression in the mitochondrial apoptotic pathway. Finally, the apoptosis induction increase observed for the preCore mutants suggests that HBeAg might have an anti-apoptotic effect in human hepatocytes. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. The sustained-release behavior and in vitro and in vivo transfection of pEGFP-loaded core-shell-structured chitosan-based composite particles

    Science.gov (United States)

    Wang, Yun; Lin, Fu-xing; Zhao, Yu; Wang, Mo-zhen; Ge, Xue-wu; Gong, Zheng-xing; Bao, Dan-dan; Gu, Yu-fang

    2014-01-01

    Novel submicron core-shell-structured chitosan-based composite particles encapsulated with enhanced green fluorescent protein plasmids (pEGFP) were prepared by complex coacervation method. The core was pEGFP-loaded thiolated N-alkylated chitosan (TACS) and the shell was pH- and temperature-responsive hydroxybutyl chitosan (HBC). pEGFP-loaded TACS-HBC composite particles were spherical, and had a mean diameter of approximately 120 nm, as measured by transmission electron microscopy and particle size analyzer. pEGFP showed sustained release in vitro for >15 days. Furthermore, in vitro transfection in human embryonic kidney 293T and human cervix epithelial cells, and in vivo transfection in mice skeletal muscle of loaded pEGFP, were investigated. Results showed that the expression of loaded pEGFP, both in vitro and in vivo, was slow but could be sustained over a long period. pEGFP expression in mice skeletal muscle was sustained for >60 days. This work indicates that these submicron core-shell-structured chitosan-based composite particles could potentially be used as a gene vector for in vivo controlled gene transfection. PMID:25364253

  14. High Photocatalytic Activity of Fe3O4-SiO2-TiO2 Functional Particles with Core-Shell Structure

    Directory of Open Access Journals (Sweden)

    Chenyang Xue

    2013-01-01

    Full Text Available This paper describes a novel method of synthesizing Fe3O4-SiO2-TiO2 functional nanoparticles with the core-shell structure. The Fe3O4 cores which were mainly superparamagnetic were synthesized through a novel carbon reduction method. The Fe3O4 cores were then modified with SiO2 and finally encapsulated with TiO2 by the sol-gel method. The results of characterizations showed that the encapsulated 700 nm Fe3O4-SiO2-TiO2 particles have a relatively uniform size distribution, an anatase TiO2 shell, and suitable magnetic properties for allowing collection in a magnetic field. These magnetic properties, large area, relative high saturation intensity, and low retentive magnetism make the particles have high dispersibility in suspension and yet enable them to be recovered well using magnetic fields. The functionality of these particles was tested by measuring the photocatalytic activity of the decolouring of methyl orange (MO and methylene blue (MB under ultraviolet light and sunlight. The results showed that the introduction of the Fe3O4-SiO2-TiO2 functional nanoparticles significantly increased the decoloration rate so that an MO solution at a concentration of 10 mg/L could be decoloured completely within 180 minutes. The particles were recovered after utilization, washing, and drying and the primary recovery ratio was 87.5%.

  15. UV-durable superhydrophobic textiles with UV-shielding properties by coating fibers with ZnO/SiO2 core/shell particles

    Science.gov (United States)

    Xue, Chao-Hua; Yin, Wei; Jia, Shun-Tian; Ma, Jian-Zhong

    2011-10-01

    ZnO/SiO2 core/shell particles were fabricated by successive coating of multilayer polyelectrolytes and then a SiO2 shell onto ZnO particles. The as-prepared ZnO/SiO2 core/shell particles were coated on poly(ethylene terephthalate) (PET) textiles, followed by hydrophobization with hexadecyltrimethoxysilane, to fabricate superhydrophobic surfaces with UV-shielding properties. Transmission electron microscopy and ζ potential analysis were employed to evidence the fabrication of ZnO/SiO2 core/shell particles. Scanning electron microscopy and thermal gravimetric analysis were conducted to investigate the surface morphologies of the textile and the coating of the fibers. Ultraviolet-visible spectrophotometry and contact angle measurement indicated that the incorporation of ZnO onto fibers imparted UV-blocking properties to the textile surface, while the coating of SiO2 shell on ZnO prohibited the photocatalytic degradation of hexadecyltrimethoxysilane by ZnO, making the as-treated PET textile surface show stable superhydrophobicity with good UV-shielding properties.

  16. Nonstructural protein 5A is incorporated into hepatitis C virus low-density particle through interaction with core protein and microtubules during intracellular transport.

    Directory of Open Access Journals (Sweden)

    Chao-Kuen Lai

    Full Text Available Nonstructural protein 5A (NS5A of hepatitis C virus (HCV serves dual functions in viral RNA replication and virus assembly. Here, we demonstrate that HCV replication complex along with NS5A and Core protein was transported to the lipid droplet (LD through microtubules, and NS5A-Core complexes were then transported from LD through early-to-late endosomes to the plasma membrane via microtubules. Further studies by cofractionation analysis and immunoelectron microscopy of the released particles showed that NS5A-Core complexes, but not NS4B, were present in the low-density fractions, but not in the high-density fractions, of the HCV RNA-containing virions and associated with the internal virion core. Furthermore, exosomal markers CD63 and CD81 were also detected in the low-density fractions, but not in the high-density fractions. Overall, our results suggest that HCV NS5A is associated with the core of the low-density virus particles which exit the cell through a preexisting endosome/exosome pathway and may contribute to HCV natural infection.

  17. Preparation of PBA-P(MMA-DMA) core-shell latex particles%PBA-P(MMA-DMA)核壳乳胶粒子的制备

    Institute of Scientific and Technical Information of China (English)

    辛丹丹; 刘喜军; 娄春华

    2016-01-01

    A novel poly-butyl methacry1ate(PBA)-poly(methyl methacrylate-dimethylaminoethyl methacrylate)[P(MMA-DMA)]core-shell latex particle containing amino groups in surface layer was prepared by a pre-emulsion semi-continuous seeded emulsion polymerization method. It was characterized through element analyzer, laser particle size analyzer, transmission electron microscope (TEM), and X-ray Photoelectron Spectroscopy(XPS). The results indicate that PBA-P(MMA-DMA)latex particles are well-defined core-shell structure, and the mean grain size of PBA core and PBA-P(MMA-DMA) core-shell latex particles are 270 nm and 340 nm respectively. There exists DMA in shell layer of PBA-P (MMA-DMA) core-shell latex particles. When DMA content in shell layer is 10.0% of MMA, the mass fraction of nitrogen in PBA- P(MMA-DMA) core-shell latex particles reaches 0.29%, equivalent of 0.78% amino in shell layer.%采用预乳化半连续种子乳液聚合方法制备了一种新型的表层含氨基的聚甲基丙烯酸丁酯(PBA)-聚(甲基丙烯酸甲酯-甲基丙烯酸二甲氨基乙酯)[P(MMA-DMA)]核壳乳胶粒子,并通过激光粒径分析仪、透射电子显微镜、X射线光电子能谱仪和元素分析仪等对其进行表征。结果表明:PBA-P(MMA-DMA)乳胶粒子为核壳结构,PBA核芯和PBA-P(MMA-DMA)核壳乳胶粒子的平均粒径分别为270,340nm;PBA-P(MMA-DMA)核壳乳胶粒子的壳层确实含有甲基丙烯酸二甲氨基乙酯(DMA),当DMA用量为甲基丙烯酸甲酯质量的10.0%时,PBA-P(MMA-DMA)核壳乳胶粒子氮元素质量分数达0.29%,折合壳层氨基质量分数达0.78%。

  18. Rapid determination of parabens in seafood sauces by high-performance liquid chromatography: A practical comparison of core-shell particles and sub-2 μm fully porous particles.

    Science.gov (United States)

    Ye, Jing; Cao, Xiaoji; Cheng, Zhuo; Qin, Ye; Lu, Yanbin

    2015-12-01

    In this work, the chromatographic performance of superficially porous particles (Halo core-shell C18 column, 50 mm × 2.1 mm, 2.7 μm) was compared with that of sub-2 μm fully porous particles (Acquity BEH C18 , 50 mm × 2.1 mm, 1.7 μm). Four parabens, methylparaben, ethylparaben, propylparaben, and butylparaben, were used as representative compounds for calculating the plate heights in a wide flow rate range and analyzed on the basis of the Van Deemter and Knox equations. Theoretical Poppe plots were constructed for each column to compare their kinetic performance. Both phases gave similar minimum plate heights when using nonreduced coordinates. Meanwhile, the flat C-term of the core-shell column provided the possibilities for applying high flow rates without significant loss in efficiency. The low backpressure of core-shell particles allowed this kind of column, especially compatible with conventional high-performance liquid chromatography systems. Based on these factors, a simple high-performance liquid chromatography method was established and validated for the determination of parabens in various seafood sauces using the Halo core-shell C18 column for separation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Estimation of irradiation-induced material damage measure of FCM fuel in LWR core

    International Nuclear Information System (INIS)

    Lee, Kyung-Hoon; Lee, Chungchan; Park, Sang-Yoon; Cho, Jin-Young; Chang, Jonghwa; Lee, Won Jae

    2014-01-01

    An irradiation-induced material damage measure on tri-isotropic (TRISO) multi-coating layers of fully ceramic micro-encapsulated (FCM) fuel to replace conventional uranium dioxide (UO 2 ) fuel for existing light water reactors (LWRs) has been estimated using a displacement per atom (DPA) cross section for a FCM fuel performance analysis. The DPA cross sections in 47 and 190 energy groups for both silicon carbide (SiC) and graphite are generated based on the molecular dynamics simulation by SRIM/TRIM. For the selected FCM fuel assembly design with FeCrAl cladding, a core depletion analysis was carried out using the DeCART2D/MASTER code system with the prepared DPA cross sections to evaluate the irradiation effect in the Korean OPR-1000. The DPA of the SiC and IPyC coating layers is estimated by comparing the discharge burnup obtained from the MASTER calculation with the burnup-dependent DPA for each coating layer calculated using DeCART2D. The results show that low uranium loading and hardened neutron spectrum compared to that of high temperature gas-cooled reactor (HTGR) result in high discharge burnup and high fast neutron fluence. In conclusion, it can be seen that the irradiation-induced material damage measure is noticeably increased under LWR operating conditions compared to HTGRs. (author)

  20. Neutrino-Induced Nucleosynthesis in Helium Shells of Early Core-Collapse Supernovae

    Directory of Open Access Journals (Sweden)

    Banerjee Projjwal

    2016-01-01

    Full Text Available We summarize our studies on neutrino-driven nucleosynthesis in He shells of early core-collapse supernovae with metallicities of Z ≲ 10−3 Z⊙. We find that for progenitors of ∼ 11–15 M⊙, the neutrons released by 4He(ν¯ee, e+n3H in He shells can be captured to produce nuclei with mass numbers up to A ∼ 200. This mechanism is sensitive to neutrino emission spectra and flavor oscillations. In addition, we find two new primary mechanisms for neutrino-induced production of 9Be in He shells. The first mechanism produces 9Be via 7Li(n,γ8Li(n,γ9Li(e− ν¯ee9Be and relies on a low explosion energy for its survival. The second mechanism operates in progenitors of ∼ 8 M⊙, where 9Be can be produced directly via 7Li(3H, n09Be during the rapid expansion of the shocked Heshell material. The light nuclei 7Li and 3H involved in these mechanisms are produced by neutrino interactions with 4He. We discuss the implications of neutrino-induced nucleosynthesis in He shells for interpreting the elemental abundances in metal-poor stars.

  1. A position sensitive parallel plate avalanche fission detector for use in particle induced fission coincidence measurements

    NARCIS (Netherlands)

    Plicht, J. van der

    1980-01-01

    A parallel plate avalanche detector developed for the detection of fission fragments in particle induced fission reactions is described. The active area is 6 × 10 cm2; it is position sensitive in one dimension with a resolution of 2.5 mm. The detector can withstand a count rate of 25000 fission

  2. Modeling the radar scatter off of high-energy neutrino-induced particle cascades in ice

    NARCIS (Netherlands)

    de Vries, Krijn D.; van Eijndhoven, Nick; O'Murchadha, Aongus; Toscano, Simona; Scholten, Olaf

    2017-01-01

    We discuss the radar detection method as a probe for high-energy neutrino induced particle cascades in ice. In a previous work we showed that the radar detection techniqe is a promising method to probe the high-energy cosmic neutrino flux above PeV energies. This was done by considering a simplified

  3. Qualitative analysis of a powdered diamond sample by particle induced X-ray emission (PIXE)

    International Nuclear Information System (INIS)

    Mabida, C.; Annegarn, H.J.; Renan, M.J.; Sellschop, J.P.F.

    The main purpose of this analysis was to determine whether nickel is present in diamond powder as a trace element. Particle induced X-ray emission (PIXE) showed unambiguously that nickel was present. Due to the convenience of PIXE in multielemental analysis, the investigations also include a number of other trace elements in the sample

  4. 14th International Conference on Particle Induced X-ray Emission ("PIXE 2015")

    Science.gov (United States)

    Przybyłowicz, Wojciech Józef; Pineda-Vargas, Carlos

    2015-11-01

    This special issue of Nuclear Instruments and Methods in Physics Research B contains the proceedings of the 14th International Conference on Particle Induced X-ray Emission ("PIXE 2015") that was held in Somerset West (South Africa) from 25th February to 3rd March 2015.

  5. Epstein–Barr virus particles induce centrosome amplification and chromosomal instability

    Science.gov (United States)

    Shumilov, Anatoliy; Tsai, Ming-Han; Schlosser, Yvonne T.; Kratz, Anne-Sophie; Bernhardt, Katharina; Fink, Susanne; Mizani, Tuba; Lin, Xiaochen; Jauch, Anna; Mautner, Josef; Kopp-Schneider, Annette; Feederle, Regina; Hoffmann, Ingrid; Delecluse, Henri-Jacques

    2017-01-01

    Infections with Epstein–Barr virus (EBV) are associated with cancer development, and EBV lytic replication (the process that generates virus progeny) is a strong risk factor for some cancer types. Here we report that EBV infection of B-lymphocytes (in vitro and in a mouse model) leads to an increased rate of centrosome amplification, associated with chromosomal instability. This effect can be reproduced with virus-like particles devoid of EBV DNA, but not with defective virus-like particles that cannot infect host cells. Viral protein BNRF1 induces centrosome amplification, and BNRF1-deficient viruses largely lose this property. These findings identify a new mechanism by which EBV particles can induce chromosomal instability without establishing a chronic infection, thereby conferring a risk for development of tumours that do not necessarily carry the viral genome. PMID:28186092

  6. Mode structure symmetry breaking of energetic particle driven beta-induced Alfvén eigenmode

    Science.gov (United States)

    Lu, Z. X.; Wang, X.; Lauber, Ph.; Zonca, F.

    2018-01-01

    The mode structure symmetry breaking of energetic particle driven Beta-induced Alfvén Eigenmode (BAE) is studied based on global theory and simulation. The weak coupling formula gives a reasonable estimate of the local eigenvalue compared with global hybrid simulation using XHMGC. The non-perturbative effect of energetic particles on global mode structure symmetry breaking in radial and parallel (along B) directions is demonstrated. With the contribution from energetic particles, two dimensional (radial and poloidal) BAE mode structures with symmetric/asymmetric tails are produced using an analytical model. It is demonstrated that the symmetry breaking in radial and parallel directions is intimately connected. The effects of mode structure symmetry breaking on nonlinear physics, energetic particle transport, and the possible insight for experimental studies are discussed.

  7. Temperature effects on drift of suspended single-domain particles induced by the Magnus force

    Science.gov (United States)

    Denisov, S. I.; Lyutyy, T. V.; Reva, V. V.; Yermolenko, A. S.

    2018-03-01

    We study the temperature dependence of the drift velocity of single-domain ferromagnetic particles induced by the Magnus force in a dilute suspension. A set of stochastic equations describing the translational and rotational dynamics of particles is derived, and the particle drift velocity that depends on components of the average particle magnetization is introduced. The Fokker-Planck equation for the probability density of magnetization orientations is solved analytically in the limit of strong thermal fluctuations for both the planar rotor and general models. Using these solutions, we calculate the drift velocity and show that the out-of-plane fluctuations of magnetization, which are not accounted for in the planar rotor model, play an important role. In the general case of arbitrary fluctuations, we investigate the temperature dependence of the drift velocity by numerically simulating a set of effective stochastic differential equations for the magnetization dynamics.

  8. Fabrication and electromagnetic properties of bio-based helical soft-core particles by way of Ni-Fe alloy electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Lan Mingming, E-mail: lan_mingming@163.com [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Zhang Deyuan; Cai Jun; Zhang Wenqiang; Yuan Liming [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2011-12-15

    Ni-Fe alloy electroplating was used as a bio-limited forming process to fabricate bio-based helical soft-core ferromagnetic particles, and a low frequency vibration device was applied to the cathode to avoid microorganism (Spirulina platens) cells adhesion to the copper net during the course of plating. The morphologies and ingredients of the coated Spirulina cells were characterized using scanning electron microscopy and energy dispersive spectrometer. The complex permittivity and permeability of the samples containing the coated Spirulina cells before and after heat treatment were measured and investigated by a vector network analyzer. The results show that the Spirulina cells after plating keep their initial helical shape, and applying low frequency vibration to the copper net cathode in the plating process can effectively prevent agglomeration and intertwinement of the Spirulina cells. The microwave absorbing and electromagnetic properties of the samples containing the coated Spirulina cells particles with heat treatment are superior to those samples containing the coated Spirulina cells particles without heat treatment. - Highlights: > We used the microorganism cells as forming template to fabricate the bio-based helical soft-core ferromagnetic particles. > Microorganism selected as forming templates was Spirulina platens, which are of natural helical shape and have high aspect ratio. > Coated Spirulina cells were a kind lightweight ferromagnetic particle.

  9. Shock-induced kelyphite formation in the core of a complex impact crater

    Science.gov (United States)

    Deseta, Natalie; Boonsue, Suporn; Gibson, Roger L.; Spray, John G.

    2017-10-01

    We present a compositional and textural analysis of shock-induced microtextures in garnet porphyroblasts in migmatitic garnet-cordierite-biotite paragneisses from the centre of the Vredefort impact structure, South Africa. Detailed imaging and major element analysis of deformation features in, and adjacent to, the garnet porphyroblasts record a complex, heterogeneous distribution of shock effects at the microscale. As the most competent silicate mineral in the assemblage, with the highest Hugoniot Elastic Limit and a wide pressure-temperature stability field, the porphyroblastic garnet preserves a more diverse shock deformation response compared to minerals such as quartz and feldspar, which underwent more comprehensive shock metamorphism and subsequent annealing. The garnet porphyroblasts display pre-impact fractures that are overprinted by later intra-granular Hertzian and distinctive planar fractures associated with the impact event. Shock-induced strain localization occurred along internal slip planes and defects, including pre-existing fractures and inclusion boundaries in the garnet. Symplectitic (kelyphitic) coronas commonly enclose the garnet porphyroblasts, and inhabit intra-granular fractures. The kelyphite assemblage in fractures with open communication beyond garnet grain boundaries is characterized by orthopyroxene—cordierite—sapphirine. Conversely, the kelyphite assemblage in closed-off intra-granular fractures is highly variable, comprising spatially restricted combinations of a secondary garnet phase with a majoritic component, Al-rich orthopyroxene, sapphirine and cordierite. The impedance contrast between garnet porphyroblasts and their inclusions further facilitated the formation of shock-induced features (Al-rich orthopyroxene coronas). Together, the textural and mineralogical data suggest that these features provide a record of oscillatory shock perturbations initiated under confining pressure beneath the transient crater floor. This

  10. Alpha-particles induce preneoplastic transformation of rat tracheal epithelial cells in culture

    International Nuclear Information System (INIS)

    Thomassen, D.G.; Seiler, F.A.; Shyr, L.-J.; Griffith, W.C.

    1990-01-01

    To characterize the potential role of high-l.e.t. radiation in respiratory carcinogenesis, the cytotoxic and transforming potency of 5.5 MeV α-particles from electroplated sources of 238 Pu were determined using primary cultures of rat tracheal epithelial cells. RBE for cell killing by α-particles versus X-rays varied with dose, and ranged between 4 and 1.5 for α doses in the range 0.2-4 Gy. At equally toxic doses (relative survival 0.18-0.2), all three agents induced similar frequencies of preneoplastic transformation. For preneoplastic transformation induced by doses of α- and X-radiations giving 80 per cent toxicity, an α RBE of 2.4 was derived. The similar RBEs for cell killing and for preneoplastic transformation suggest an association between the type or degree of radiation-induced damage responsible for both cell killing and cell transformation. (author)

  11. Spatiotemporal kinetics of γ-H2AX protein on charged particles induced DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Niu, H., E-mail: hniu@mx.nthu.edu.tw [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu, Taiwan (China); Chang, H.C. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan (China); Cho, I.C. [Institute for Radiological Research, Chang Gung University and Chang Gung Memorial Hospital, Taoyuan, Taiwan (China); Chen, C.H. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu, Taiwan (China); Liu, C.S. [Cancer Center of Taipei Veterans General Hospital, Taipei, Taiwan (China); Chou, W.T. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan (China)

    2014-08-15

    Highlights: • Charged particles can induce more complex DNA damages, and these complex damages have higher ability to cause the cell death or cell carcinogenesis. • In this study, we used γ-H2AX protein to investigate the spatiotemporal kinetics of DNA double strand breaks in particle irradiated HeLa cells. • The HeLa cells were irradiated by 400 keV alpha-particles in four different dosages. • The result shows that a good linear relationship can be observed between foci number and radiation dose. • The data shows that the dissolution rate of γ-H2AX foci agree with the two components DNA repairing model, and it was decreasing as the radiation dose increased. • These results suggest that charged particles can induce more complex DNA damages and causing the retardation of DNA repair. - Abstract: In several researches, it has been demonstrated that charged particles can induce more complex DNA damages. These complex damages have higher ability to cause the cell death or cell carcinogenesis. For this reason, clarifying the DNA repair mechanism after charged particle irradiation plays an important role in the development of charged particle therapy and space exploration. Unfortunately, the detail spatiotemporal kinetic of DNA damage repair is still unclear. In this study, we used γ-H2AX protein to investigate the spatiotemporal kinetics of DNA double strand breaks in alpha-particle irradiated HeLa cells. The result shows that the intensity of γ-H2AX foci increased gradually, and reached to its maximum at 30 min after irradiation. A good linear relationship can be observed between foci intensity and radiation dose. After 30 min, the γ-H2AX foci intensity was decreased with time passed, but remained a large portion (∼50%) at 48 h passed. The data show that the dissolution rate of γ-H2AX foci agreed with two components DNA repairing model. These results suggest that charged particles can induce more complex DNA damages and causing the retardation of DNA

  12. Competition between excited core states and 1homega single-particle excitations at comparable energies in {sup 207}Pb from photon scattering

    Energy Technology Data Exchange (ETDEWEB)

    Pietralla, N., E-mail: pietralla@ikp.tu-darmstadt.d [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany); Li, T.C. [Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Fritzsche, M. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Ahmed, M.W. [Triangle Universities Nuclear Laboratory (TUNL), Duke University, Durham, NC 27708 (United States); Ahn, T.; Costin, A. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Nuclear Structure Laboratory, SUNY at Stony Brook, Stony Brook, NY 11794-3800 (United States); Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany); Enders, J. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Li, J. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Mueller, S.; Neumann-Cosel, P. von [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Pinayev, I.V. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Ponomarev, V.Yu.; Savran, D. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, 64289 Darmstadt (Germany); Tonchev, A.P.; Tornow, W.; Weller, H.R. [Triangle Universities Nuclear Laboratory (TUNL), Duke University, Durham, NC 27708 (United States); Werner, V. [A.W. Wright Nuclear Structure Laboratory (WNSL), Yale University, New Haven, CT (United States); Wu, Y.K. [Duke Free Electron Laser Laboratory (DFELL), Duke University, Durham, NC 27708 (United States); Zilges, A. [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Koeln (Germany)

    2009-10-26

    The Pb(gamma{sup -}>,gamma{sup '}) photon scattering reaction has been studied with the nearly monochromatic, linearly polarized photon beams at the High Intensity gamma-ray Source (HIgammaS) at the DFELL. Azimuthal scattering intensity asymmetries measured with respect to the polarization plane of the beam have been used for the first time to assign both the spin and parity quantum numbers of dipole excited states of {sup 206,207,208}Pb at excitation energies in the vicinity of 5.5 MeV. Evidence for dominant particle-core coupling is deduced from these results along with information on excitation energies and electromagnetic transition matrix elements. Implications of the existence of weakly coupled states built on highly excited core states in competition with 1homega single particle (hole) excitations at comparable energies are discussed.

  13. Probiotics protect mice from CoCrMo particles-induced osteolysis

    Directory of Open Access Journals (Sweden)

    Wang Z

    2017-07-01

    Full Text Available Zhenheng Wang,* Kaiwen Xue,* Maosheng Bai, Zhantao Deng, Jingjing Gan, Gang Zhou, Hongbo Qian,* Nirong Bao, Jianning Zhao Department of Orthopaedics, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, People’s Republic of China *These authors contributed equally to this work Abstract: Wear particle-induced inflammatory osteolysis is the primary cause of aseptic loosening, which is the most common reason for total hip arthroplasty (THA failure in the med- and long term. Recent studies have suggested an important role of gut microbiota (GM in modulating the host metabolism and immune system, leading to alterations in bone mass. Probiotic bacteria administered in adequate amounts can alter the composition of GM and confer health benefits to the host. Given the inflammatory osteolysis that occurs in wear debris-induced prosthesis loosening, we examined whether the probiotic Lactobacillus casei could reduce osteolysis in a mouse calvarial resorption model. In this study, L. casei markedly protected mice from CoCrMo particles (CoPs-induced osteolysis. Osteoclast gene markers and the number of osteoclasts were significantly decreased in L. casei-treated mice. Probiotic treatment decreased the M1-like macrophage phenotype indicated by downregulation of tumor necrosis factor α (TNF-α, interleukin (IL-6 and inducible nitric oxide synthase (iNOS and increased the M2-like macrophage phenotype indicated by upregulation of IL-4, IL-10 and arginase. Collectively, these results indicated that the L. casei treatment modulated the immune status and suppressed wear particle-induced osteolysis in vivo. Thus, probiotic treatment may represent a potential preventive and therapeutic approach to reduced wear debris-induced osteolysis. Keywords: wear particles, gut microbiota, nanotoxicity, macrophage polarization, inflammatory cytokines, aseptic loosening

  14. Flow induced particle migration in fresh concrete: Theoretical frame, numerical simulations and experimental results on model fluids

    DEFF Research Database (Denmark)

    Spangenberg, J.; Roussel, N.; Hattel, J.H.

    2012-01-01

    In this paper, we describe and compare the various physical phenomena which potentially lead to flow induced particle migration in concrete. We show that, in the case of industrial casting of concrete, gravity induced particle migration dominates all other potential sources of heterogeneities ind...

  15. Fluoride adsorption from aqueous solution by magnetic core-shell Fe_3O_4@alginate-La particles fabricated via electro-coextrusion

    International Nuclear Information System (INIS)

    Zhang, Yahui; Lin, Xiaoyan; Zhou, Quisheng; Luo, Xuegang

    2016-01-01

    Graphical abstract: The magnetic core-shell Fe_3O_4@Alg-La particles were fabricated successfully by a simple method of electro-coextrusion, and employed as an adsorbent for separation of fluoride from aqueous solution. - Highlights: • Magnetic core-shell Fe_3O_4@Alg-La particles were prepared by electro-coextrusion. • The maximum adsorption capacity for fluoride at 298.15 K was 45.230 mg/g. • The adsorbent has a good saturation magnetization value. • The adsorbent has a great potential in removing the fluoride. - Abstract: The magnetic core-shell Fe_3O_4@Alg-La particles were fabricated successfully by a simple method of electro-coextrusion, and employed as an adsorbent for separation of fluoride from aqueous solution. Main factors affecting the removal of fluoride, including pH, adsorbent dosage, initial concentration, temperature and contact time were investigated. The adsorption isotherm and adsorption kinetics were studied to understand the adsorption process in detail. The experimental data were fitted well by the non-linear Freundlich isotherm and linear pseudo-second-order model, the maximum fluoride adsorption capacity was 45.230 mg/g at pH 4, 298.15 K. Thermodynamic parameters indicated that the fluoride adsorption process was feasible and spontaneous. The presence of other anions like Cl"−, SO_4"2"−, HCO_3"− and PO_4"3"− had almost no effect on the fluoride adsorption. The adsorbent can be easily separated from the solution by a magnet. The magnetic core-shell Fe_3O_4@Alg-La particles before and after fluoride adsorption were studied by SEM, FTIR, EDX and XPS, which indicated that the adsorption mechanism may be related to electrostatic attraction and Lewis acid-base interaction.

  16. Fluoride adsorption from aqueous solution by magnetic core-shell Fe{sub 3}O{sub 4}@alginate-La particles fabricated via electro-coextrusion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yahui [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Engineering Research Center of Biomass Materials, Ministry of Education, Mianyang 621010, Sichuan (China); Lin, Xiaoyan, E-mail: lxy20100205@163.com [School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, Sichuan (China); Engineering Research Center of Biomass Materials, Ministry of Education, Mianyang 621010, Sichuan (China); Zhou, Quisheng [A State Key Laboratory of Pulp & Paper Engineering, South China University of Technology, Guangzhou 510640 (China); Luo, Xuegang [Engineering Research Center of Biomass Materials, Ministry of Education, Mianyang 621010, Sichuan (China)

    2016-12-15

    Graphical abstract: The magnetic core-shell Fe{sub 3}O{sub 4}@Alg-La particles were fabricated successfully by a simple method of electro-coextrusion, and employed as an adsorbent for separation of fluoride from aqueous solution. - Highlights: • Magnetic core-shell Fe{sub 3}O{sub 4}@Alg-La particles were prepared by electro-coextrusion. • The maximum adsorption capacity for fluoride at 298.15 K was 45.230 mg/g. • The adsorbent has a good saturation magnetization value. • The adsorbent has a great potential in removing the fluoride. - Abstract: The magnetic core-shell Fe{sub 3}O{sub 4}@Alg-La particles were fabricated successfully by a simple method of electro-coextrusion, and employed as an adsorbent for separation of fluoride from aqueous solution. Main factors affecting the removal of fluoride, including pH, adsorbent dosage, initial concentration, temperature and contact time were investigated. The adsorption isotherm and adsorption kinetics were studied to understand the adsorption process in detail. The experimental data were fitted well by the non-linear Freundlich isotherm and linear pseudo-second-order model, the maximum fluoride adsorption capacity was 45.230 mg/g at pH 4, 298.15 K. Thermodynamic parameters indicated that the fluoride adsorption process was feasible and spontaneous. The presence of other anions like Cl{sup −}, SO{sub 4}{sup 2−}, HCO{sub 3}{sup −} and PO{sub 4}{sup 3−} had almost no effect on the fluoride adsorption. The adsorbent can be easily separated from the solution by a magnet. The magnetic core-shell Fe{sub 3}O{sub 4}@Alg-La particles before and after fluoride adsorption were studied by SEM, FTIR, EDX and XPS, which indicated that the adsorption mechanism may be related to electrostatic attraction and Lewis acid-base interaction.

  17. Enhanced stability of a chimeric hepatitis B core antigen virus-like-particle (HBcAg-VLP) by a C-terminal linker-hexahistidine-peptide.

    Science.gov (United States)

    Schumacher, Jens; Bacic, Tijana; Staritzbichler, René; Daneschdar, Matin; Klamp, Thorsten; Arnold, Philipp; Jägle, Sabrina; Türeci, Özlem; Markl, Jürgen; Sahin, Ugur

    2018-04-13

    Virus-like-particles (VLPs) are attractive nanoparticulate scaffolds for broad applications in material/biological sciences and medicine. Prior their functionalization, specific adaptations have to be carried out. These adjustments frequently lead to disordered particles, but the particle integrity is an essential factor for the VLP suitability. Therefore, major requirements for particle stabilization exist. The objective of this study was to evaluate novel stabilizing elements for functionalized chimeric hepatitis B virus core antigen virus-like particles (HBcAg-VLP), with beneficial characteristics for vaccine development, imaging or delivery. The effects of a carboxy-terminal polyhistidine-peptide and an intradimer disulfide-bridge on the stability of preclinically approved chimeric HBcAg-VLPs were assessed. We purified recombinant chimeric HBcAg-VLPs bearing different modified C-termini and compared their physical and chemical particle stability by quantitative protein-biochemical and biophysical techniques. We observed lower chemical resistance of T = 3- compared to T = 4-VLP (triangulation number) capsids and profound impairment of accessibility of hexahistidine-peptides in assembled VLPs. Histidines attached to the C-terminus were associated with superior mechanical and/or chemical particle stability depending on the number of histidine moieties. A molecular modeling approach based on cryo-electron microscopy and biolayer interferometry revealed the underlying structural mechanism for the strengthening of the integrity of VLPs. Interactions triggering capsid stabilization occur on a highly conserved residue on the basis of HBcAg-monomers as well as on hexahistidine-peptides of adjacent monomers. This new stabilization mechanism appears to mimic an evolutionary conserved stabilization concept for hepadnavirus core proteins. These findings establish the genetically simply transferable C-terminal polyhistidine-peptide as a general stabilizing element

  18. The Impact of Central and Peripheral Cyclooxygenase Enzyme Inhibition on Exercise-Induced Elevations in Core Body Temperature.

    NARCIS (Netherlands)

    Veltmeijer, M.T.W.; Veeneman, D.; Bongers, C.C.W.G.; Netea, M.G.; Meer, J.W.M. van der; Eijsvogels, T.M.H.; Hopman, M.T.E.

    2017-01-01

    PURPOSE: Exercise increases core body temperature (TC) due to metabolic heat production. However, the exercise-induced release of inflammatory cytokines including interleukin-6 (IL-6) may also contribute to the rise in TC by increasing the hypothalamic temperature set point. This study investigated

  19. Rotating magnetic field induced oscillation of magnetic particles for in vivo mechanical destruction of malignant glioma.

    Science.gov (United States)

    Cheng, Yu; Muroski, Megan E; Petit, Dorothée C M C; Mansell, Rhodri; Vemulkar, Tarun; Morshed, Ramin A; Han, Yu; Balyasnikova, Irina V; Horbinski, Craig M; Huang, Xinlei; Zhang, Lingjiao; Cowburn, Russell P; Lesniak, Maciej S

    2016-02-10

    Magnetic particles that can be precisely controlled under a magnetic field and transduce energy from the applied field open the way for innovative cancer treatment. Although these particles represent an area of active development for drug delivery and magnetic hyperthermia, the in vivo anti-tumor effect under a low-frequency magnetic field using magnetic particles has not yet been demonstrated. To-date, induced cancer cell death via the oscillation of nanoparticles under a low-frequency magnetic field has only been observed in vitro. In this report, we demonstrate the successful use of spin-vortex, disk-shaped permalloy magnetic particles in a low-frequency, rotating magnetic field for the in vitro and in vivo destruction of glioma cells. The internalized nanomagnets align themselves to the plane of the rotating magnetic field, creating a strong mechanical force which damages the cancer cell structure inducing programmed cell death. In vivo, the magnetic field treatment successfully reduces brain tumor size and increases the survival rate of mice bearing intracranial glioma xenografts, without adverse side effects. This study demonstrates a novel approach of controlling magnetic particles for treating malignant glioma that should be applicable to treat a wide range of cancers. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Ion desorption induced by charged particle beams: mechanisms and mass spectroscopy

    International Nuclear Information System (INIS)

    Silveira, E.F. da; Schweikert, E.A.

    1988-01-01

    Surface analysis, through desorption, induced by fast particles, is presented and discussed. The stopping of projectils is essentially made by collisions with the target electrons. The desorbed particles are generally emmited with kinetic energy from 0.1 to 20 eV. Mass, charge, velocity and emission angle give information about the surface components, its structure as well as beam-solid interaction processes. Time-of-flight mass spectroscopy of desorbed ions, determine the mass of organic macromolecules and biomolecules. (A.C.A.S.) [pt

  1. Laser-induced incandescence of suspended particles as a source of excitation of dye luminescence

    CERN Document Server

    Zelensky, S

    2003-01-01

    The interaction of pulsed YAG-Nd sup 3 sup + laser radiation with submicron light-absorbing particles suspended in an aqueous solution of Rhodamine 6G is investigated experimentally. The experiments demonstrate that the laser-induced incandescence of suspended particles excites the luminescence of the dissolved dye molecules. The mechanism of the luminescence excitation consists in the reabsorption of the thermal radiation within the volume of the sample cell. On the ground of this mechanism of excitation, a method of measurement of the luminescence quantum yield is proposed and realized. The method requires the knowledge of the geometrical parameters of the cell and does not require the use of reference samples.

  2. Gravitationally induced particle production and its impact on the WIMP abundance

    Directory of Open Access Journals (Sweden)

    I. Baranov

    2015-12-01

    Full Text Available A large set of independent astronomical observations have provided a strong evidence for nonbaryonic dark matter in the Universe. One of the most investigated candidates is an unknown long-lived Weakly Interacting Massive Particle (WIMP which was in thermal equilibrium with the primeval plasma. Here we investigate the WIMP abundance based on the relativistic kinetic treatment for gravitationally induced particle production recently proposed in the literature (Lima and Baranov, 2014 [16]. The new evolution equation is deduced and solved both numerically and through a semi-analytical approach. The predictions of the WIMP observables are discussed and compared with the ones obtained in the standard approach.

  3. Gravitationally induced adiabatic particle production: from big bang to de Sitter

    Science.gov (United States)

    de Haro, Jaume; Pan, Supriya

    2016-08-01

    In the background of a flat homogeneous and isotropic space-time, we consider a scenario of the Universe driven by the gravitationally induced ‘adiabatic’ particle production with constant creation rate. We have shown that this Universe attains a big bang singularity in the past and at late-time it asymptotically becomes de Sitter. To clarify this model Universe, we performed a dynamical analysis and found that the Universe attains a thermodynamic equilibrium in this late de Sitter phase. Finally, for the first time, we have discussed the possible effects of ‘adiabatic’ particle creations in the context of loop quantum cosmology.

  4. Gravitationally induced adiabatic particle production: from big bang to de Sitter

    International Nuclear Information System (INIS)

    Haro, Jaume de; Pan, Supriya

    2016-01-01

    In the background of a flat homogeneous and isotropic space–time, we consider a scenario of the Universe driven by the gravitationally induced ‘adiabatic’ particle production with constant creation rate. We have shown that this Universe attains a big bang singularity in the past and at late-time it asymptotically becomes de Sitter. To clarify this model Universe, we performed a dynamical analysis and found that the Universe attains a thermodynamic equilibrium in this late de Sitter phase. Finally, for the first time, we have discussed the possible effects of ‘adiabatic’ particle creations in the context of loop quantum cosmology. (paper)

  5. Voltage-Induced Nonlinear Conduction Properties of Epoxy Resin/Micron-Silver Particles Composites

    Science.gov (United States)

    Qu, Zhaoming; Lu, Pin; Yuan, Yang; Wang, Qingguo

    2018-01-01

    The nonlinear conduction properties of epoxy resin (ER)/micron-silver particles (MP) composites were investigated. Under sufficient high intensity applied constant voltage, the obvious nonlinear conduction properties of the samples with volume fraction 25% were found. With increments in the voltage, the conductive switching effect was observed. The nonlinear conduction mechanism of the ER/MP composites under high applied voltages could be attributed to the electrical current conducted via discrete paths of conductive particles induced by the electric field. The test results show that the ER/MP composites with nonlinear conduction properties are of great potential application in electromagnetic protection of electron devices and systems.

  6. Induced fission track distribution from highly radioactive particles in fallout materials

    International Nuclear Information System (INIS)

    Hashimoto, Tetsuo; Okada, Tatemichi

    1987-01-01

    Some highly radioactive fallout particles (GPs) from the 19th Chinese nuclear detonation were followed to the neutron irradiation in a reactor after sandwiched with mica detectors. The interesting star-like fission track patterns were revealed on the etched surface of the mica detectors. The simple chemical separation procedure for the GPs was applied for the separation of U and Pu as fissile elements and the both resultant fractions were examined with the similar high sensitive fission tracking detection. Subsequently, a representative track pattern from a black spherical particle was subjected to the determination of fissile nuclide content; comparing the total fission events evaluated on the basis of the numerical calculation of track densities with the total thermal neutron fluence. The results implied that the uranium is responsible for the main fissile nuclide remaining within a particle as unfissioned fractions and should be certainly enriched with respect to U-235 within such small fallout particles. This sophisticated method was also applied to determine the dead GPs, which have been highly radioactive particles just after the detonations, in the rain and snow-residual materials. Many induced star-like fission tracks verified certainly that there remains a lot of dead particles in the atmosheric environment till nowadays. (author)

  7. Virus-like particles vaccine containing Clonorchis sinensis tegumental protein induces partial protection against Clonorchis sinensis infection.

    Science.gov (United States)

    Lee, Dong-Hun; Kim, Ah-Ra; Lee, Su-Hwa; Quan, Fu-Shi

    2017-12-29

    Human clonorchiasis, caused by the infection of Clonorchis sinensis, is one of the major health problems in Southeast Asia. However, vaccine efficacy against C. sinensis infection remains largely unknown. In this study, for the first time, we generated virus-like particles (VLPs) vaccine containing the C. sinensis tegumental protein 22.3 kDa (CsTP 22.3) and the influenza matrix protein (M1) as a core protein, and investigated the vaccine efficacy in Sprague-Dawley rats. Intranasal immunization of VLPs vaccine induced C. sinensis-specific IgG, IgG2a and IgG2c in the sera and IgA responses in the feces and intestines. Notably, upon challenge infection with C. sinensis metacercariae, significantly lower adult worm loads (70.2%) were measured in the liver of rats immunized with VLPs, compared to those of naïve rats. Furthermore, VLPs immunization induced antibody secreting cells (ASC) responses and CD4+/CD8+ T cell responses in the spleen. Our results indicated that VLPs vaccine containing C. sinensis CsTP 22.3 kDa provided partial protection against C. sisnensis infection. Thus, VLPs could be a potential vaccine candidate against C. sinensis.

  8. Decrease of GSK3β phosphorylation in the rat nucleus accumbens core enhances cocaine-induced hyper-locomotor activity.

    Science.gov (United States)

    Kim, Wha Y; Jang, Ju K; Lee, Jung W; Jang, Hyunduk; Kim, Jeong-Hoon

    2013-06-01

    Glycogen synthase kinase 3β (GSK3β), which is abundantly present in the brain, is known to contribute to psychomotor stimulant-induced locomotor behaviors. However, most studies have been focused in showing that GSK3β is able to attenuate psychomotor stimulants-induced hyperactivity by increasing its phosphorylation levels in the nucleus accumbens (NAcc). So, here we examined in the opposite direction about the effects of decreased phosphorylation of GSK3β in the NAcc core on both basal and cocaine-induced locomotor activity by a bilateral microinjection into this site of an artificially synthesized peptide, S9 (0.5 or 5.0 μg/μL), which contains sequences around N-terminal serine 9 residue of GSK3β. We found that decreased levels of GSK3β phosphorylation in the NAcc core enhance cocaine-induced hyper-locomotor activity, while leaving basal locomotor activity unchanged. This is the first demonstration, to our knowledge, that the selective decrease of GSK3β phosphorylation levels in the NAcc core may contribute positively to cocaine-induced locomotor activity, while this is not sufficient for the generation of locomotor behavior by itself without cocaine. Taken together, these findings importantly suggest that GSK3β may need other molecular targets which are co-activated (or deactivated) by psychomotor stimulants like cocaine to contribute to generation of locomotor behaviors. © 2013 International Society for Neurochemistry.

  9. Maturation of the viral core enhances the fusion of HIV-1 particles with primary human T cells and monocyte-derived macrophages

    International Nuclear Information System (INIS)

    Jiang Jiyang; Aiken, Christopher

    2006-01-01

    HIV-1 infection requires fusion of viral and cellular membranes in a reaction catalyzed by the viral envelope proteins gp120 and gp41. We recently reported that efficient HIV-1 particle fusion with target cells is linked to maturation of the viral core by an activity of the gp41 cytoplasmic domain. Here, we show that maturation enhances the fusion of a variety of recombinant viruses bearing primary and laboratory-adapted Env proteins with primary human CD4 + T cells. Overall, HIV-1 fusion was more dependent on maturation for viruses bearing X4-tropic envelope proteins than for R5-tropic viruses. Fusion of HIV-1 with monocyte-derived macrophages was also dependent on particle maturation. We conclude that the ability to couple fusion to particle maturation is a common feature of HIV-1 Env proteins and may play an important role during HIV-1 replication in vivo

  10. The Phospholipid:Diacylglycerol Acyltransferase Lro1 Is Responsible for Hepatitis C Virus Core-Induced Lipid Droplet Formation in a Yeast Model System.

    Directory of Open Access Journals (Sweden)

    Shingo Iwasa

    Full Text Available Chronic infection with the hepatitis C virus frequently induces steatosis, which is a significant risk factor for liver pathogenesis. Steatosis is characterized by the accumulation of lipid droplets in hepatocytes. The structural protein core of the virus induces lipid droplet formation and localizes on the surface of the lipid droplets. However, the precise molecular mechanisms for the core-induced formation of lipid droplets remain elusive. Recently, we showed that the expression of the core protein in yeast as a model system could induce lipid droplet formation. In this study, we probed the cellular factors responsible for the formation of core-induced lipid-droplets in yeast cells. We demonstrated that one of the enzymes responsible for triglyceride synthesis, a phospholipid:diacylglycerol acyltransferase (Lro1, is required for the core-induced lipid droplet formation. While core proteins inhibit Lro1 degradation and alter Lro1 localization, the characteristic localization of Lro1 adjacent to the lipid droplets appeared to be responsible for the core-induced lipid droplet formation. RNA virus genomes have evolved using high mutation rates to maintain their ability to replicate. Our observations suggest a functional relationship between the core protein with hepatocytes and yeast cells. The possible interactions between core proteins and the endoplasmic reticulum membrane affect the mobilization of specific proteins.

  11. Size and alloying induced shift in core and valence bands of Pd-Ag and Pd-Cu nanoparticles

    International Nuclear Information System (INIS)

    Sengar, Saurabh K.; Mehta, B. R.; Govind

    2014-01-01

    In this report, X-ray photoelectron spectroscopy studies have been carried out on Pd, Ag, Cu, Pd-Ag, and Pd-Cu nanoparticles having identical sizes corresponding to mobility equivalent diameters of 60, 40, and 20 nm. The nanoparticles were prepared by the gas phase synthesis method. The effect of size on valence and core levels in metal and alloy nanoparticles has been studied by comparing the values to those with the 60 nm nanoparticles. The effect of alloying has been investigated by comparing the valence and core level binding energies of Pd-Cu and Pd-Ag alloy nanoparticles with the corresponding values for Pd, Ag, and Cu nanoparticles of identical sizes. These effects have been explained in terms of size induced lattice contractions, alloying induced charge transfer, and hybridization effects. The observation of alloying and size induced binding energy shifts in bimetallic nanoparticles is important from the point of view of hydrogen reactivity

  12. Low power loss and field-insensitive permeability of Fe-6.5%Si powder cores with manganese oxide-coated particles

    Energy Technology Data Exchange (ETDEWEB)

    Li, Junnan, E-mail: junnanli1991@163.com, E-mail: rzhgong@hust.edu.cn; Wang, Xian; Xu, Xiaojun; Gong, Rongzhou, E-mail: junnanli1991@163.com, E-mail: rzhgong@hust.edu.cn; Feng, Zekun [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Yajie; Harris, V. G. [Department of Electrical and Computer Engineering, Center for Microwave Magnetic Materials and Integrated Circuits, Northeastern University, Boston, Massachusetts 02115 (United States)

    2015-05-07

    Fe-6.5%Si alloy powders coated with manganese oxides using an innovative in situ process were investigated. The in-situ coating of the insulating oxides was realized with a KMnO{sub 4} solution by a chemical process. The insulating manganese oxides with mixed valance state were verified by X-ray photoelectron spectroscopy analysis. The thickness of the insulating layer on alloy particles was determined to be in a range of 20–210 nm, depending upon the KMnO{sub 4} concentration. The powder core loss and the change in permeability under a DC-bias field were measured at frequencies ranging from 50 to 100 kHz. The experiments indicated that the Fe-6.5%Si powder cores with a 210 nm-thick manganese oxide layer not only showed a low core loss of 459 mW/cm{sup 3} at 100 kHz but also showed a small reduction in permeability (μ(H)/μ(0) = 85% for μ = 42) at a DC-bias field of 80 Oe. This work has defined a novel pathway to realizing low core loss and field-insensitive permeability for Fe-Si powder cores.

  13. Charged-particle magnetic-quadrupole spectrometer for neutron induced reactions

    International Nuclear Information System (INIS)

    Haight, R.C.; Grimes, S.M.; Tuckey, B.J.; Anderson, J.D.

    1975-01-01

    A spectrometer has been developed for measuring the charged particle production cross sections and spectra in neutron-induced reactions. The spectrometer consists of a magnetic quadrupole doublet which focuses the charged particles onto a silicon surface barrier detector telescope which is 2 meters or more from the irradiated sample. Collimators, shielding, and the large source-to-detector distance reduce the background enough to use the spectrometer with a 14-MeV neutron source producing 4 . 10 12 n/s. The spectrometer has been used in investigations of proton, deuteron, and alpha particle production by 14-MeV neutrons incident on various materials. Protons with energies as low as 1.1 MeV have been measured. The good resolution of the detectors has also made possible an improved measurement of the neutron- neutron scattering length from the 0 0 proton spectrum from deuteron breakup by 14-MeV neutrons

  14. Charge neutralization as the major factor for the assembly of nucleocapsid-like particles from C-terminal truncated hepatitis C virus core protein.

    Science.gov (United States)

    de Souza, Theo Luiz Ferraz; de Lima, Sheila Maria Barbosa; Braga, Vanessa L de Azevedo; Peabody, David S; Ferreira, Davis Fernandes; Bianconi, M Lucia; Gomes, Andre Marco de Oliveira; Silva, Jerson Lima; de Oliveira, Andréa Cheble

    2016-01-01

    Hepatitis C virus (HCV) core protein, in addition to its structural role to form the nucleocapsid assembly, plays a critical role in HCV pathogenesis by interfering in several cellular processes, including microRNA and mRNA homeostasis. The C-terminal truncated HCV core protein (C124) is intrinsically unstructured in solution and is able to interact with unspecific nucleic acids, in the micromolar range, and to assemble into nucleocapsid-like particles (NLPs) in vitro . The specificity and propensity of C124 to the assembly and its implications on HCV pathogenesis are not well understood. Spectroscopic techniques, transmission electron microscopy and calorimetry were used to better understand the propensity of C124 to fold or to multimerize into NLPs when subjected to different conditions or in the presence of unspecific nucleic acids of equivalent size to cellular microRNAs. The structural analysis indicated that C124 has low propensity to self-folding. On the other hand, for the first time, we show that C124, in the absence of nucleic acids, multimerizes into empty NLPs when subjected to a pH close to its isoelectric point (pH ≈ 12), indicating that assembly is mainly driven by charge neutralization. Isothermal calorimetry data showed that the assembly of NLPs promoted by nucleic acids is enthalpy driven. Additionally, data obtained from fluorescence correlation spectroscopy show that C124, in nanomolar range, was able to interact and to sequester a large number of short unspecific nucleic acids into NLPs. Together, our data showed that the charge neutralization is the major factor for the nucleocapsid-like particles assembly from C-terminal truncated HCV core protein. This finding suggests that HCV core protein may physically interact with unspecific cellular polyanions, which may correspond to microRNAs and mRNAs in a host cell infected by HCV, triggering their confinement into infectious particles.

  15. Charge neutralization as the major factor for the assembly of nucleocapsid-like particles from C-terminal truncated hepatitis C virus core protein

    Directory of Open Access Journals (Sweden)

    Theo Luiz Ferraz de Souza

    2016-11-01

    Full Text Available Background Hepatitis C virus (HCV core protein, in addition to its structural role to form the nucleocapsid assembly, plays a critical role in HCV pathogenesis by interfering in several cellular processes, including microRNA and mRNA homeostasis. The C-terminal truncated HCV core protein (C124 is intrinsically unstructured in solution and is able to interact with unspecific nucleic acids, in the micromolar range, and to assemble into nucleocapsid-like particles (NLPs in vitro. The specificity and propensity of C124 to the assembly and its implications on HCV pathogenesis are not well understood. Methods Spectroscopic techniques, transmission electron microscopy and calorimetry were used to better understand the propensity of C124 to fold or to multimerize into NLPs when subjected to different conditions or in the presence of unspecific nucleic acids of equivalent size to cellular microRNAs. Results The structural analysis indicated that C124 has low propensity to self-folding. On the other hand, for the first time, we show that C124, in the absence of nucleic acids, multimerizes into empty NLPs when subjected to a pH close to its isoelectric point (pH ≈ 12, indicating that assembly is mainly driven by charge neutralization. Isothermal calorimetry data showed that the assembly of NLPs promoted by nucleic acids is enthalpy driven. Additionally, data obtained from fluorescence correlation spectroscopy show that C124, in nanomolar range, was able to interact and to sequester a large number of short unspecific nucleic acids into NLPs. Discussion Together, our data showed that the charge neutralization is the major factor for the nucleocapsid-like particles assembly from C-terminal truncated HCV core protein. This finding suggests that HCV core protein may physically interact with unspecific cellular polyanions, which may correspond to microRNAs and mRNAs in a host cell infected by HCV, triggering their confinement into infectious particles.

  16. Particle induced X-ray emission and complementary nuclear methods for trace element determination; Plenary lecture

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, S A.E. [Lund Univ. (Sweden). Dept. of Nuclear Physics

    1992-03-01

    In this review the state-of-the-art of particle induced X-ray emission (PIXE) methods for the determination of trace elements is described. The developmental work has mostly been carried out in nuclear physics laboratories, where accelerators are available, but now the increased interest has led to the establishment of other dedicated PIXE facilities. The reason for this interest is the versatility, high sensitivity and multi-element capability of PIXE analysis. A further very important advantage is that PIXE can be combined with the microbeam technique, which makes elemental mapping with a spatial resolution of about 1 {mu}m possible. As a technique, PIXE can also be combined with other nuclear reactions such as elastic scattering and particle-induced gamma emission, so that light elements can be determined. The usefulness of PIXE is illustrated by a number of typical applications in biology, medicine, geology, air pollution research, archaeology and the arts. (author).

  17. Ultrafine carbon particles promote rotenone-induced dopamine neuronal loss through activating microglial NADPH oxidase

    International Nuclear Information System (INIS)

    Wang, Yinxi; Liu, Dan; Zhang, Huifeng; Wang, Yixin; Wei, Ling; Liu, Yutong; Liao, Jieying; Gao, Hui-Ming; Zhou, Hui

    2017-01-01

    Background: Atmospheric ultrafine particles (UFPs) and pesticide rotenone were considered as potential environmental risk factors for Parkinson's disease (PD). However, whether and how UFPs alone and in combination with rotenone affect the pathogenesis of PD remains largely unknown. Methods: Ultrafine carbon black (ufCB, a surrogate of UFPs) and rotenone were used individually or in combination to determine their roles in chronic dopaminergic (DA) loss in neuron-glia, and neuron-enriched, mix-glia cultures. Immunochemistry using antibody against tyrosine hydroxylase was performed to detect DA neuronal loss. Measurement of extracellular superoxide and intracellular reactive oxygen species (ROS) were performed to examine activation of NADPH oxidase. Genetic deletion and pharmacological inhibition of NADPH oxidase and MAC-1 receptor in microglia were employed to examine their role in DA neuronal loss triggered by ufCB and rotenone. Results: In rodent midbrain neuron-glia cultures, ufCB and rotenone alone caused neuronal death in a dose-dependent manner. In particularly, ufCB at doses of 50 and 100 μg/cm 2 induced significant loss of DA neurons. More importantly, nontoxic doses of ufCB (10 μg/cm 2 ) and rotenone (2 nM) induced synergistic toxicity to DA neurons. Microglial activation was essential in this process. Furthermore, superoxide production from microglial NADPH oxidase was critical in ufCB/rotenone-induced neurotoxicity. Studies in mix-glia cultures showed that ufCB treatment activated microglial NADPH oxidase to induce superoxide production. Firstly, ufCB enhanced the expression of NADPH oxidase subunits (gp91 phox , p47 phox and p40 phox ); secondly, ufCB was recognized by microglial surface MAC-1 receptor and consequently promoted rotenone-induced p47 phox and p67 phox translocation assembling active NADPH oxidase. Conclusion: ufCB and rotenone worked in synergy to activate NADPH oxidase in microglia, leading to oxidative damage to DA neurons. Our

  18. Ultrafine carbon particles promote rotenone-induced dopamine neuronal loss through activating microglial NADPH oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yinxi; Liu, Dan; Zhang, Huifeng; Wang, Yixin [Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, 100191 (China); Wei, Ling [Beijing Center for Physical & Chemical Analysis, Beijing 100089 (China); Liu, Yutong [School of Life Science, Beijing Normal University, Beijing 100875 (China); Liao, Jieying [Department of Translational Medicine, Xiamen Institute of Rare Earth Materials, Chinese Academy of Sciences, Xiamen 361024 (China); Gao, Hui-Ming [Model Animal Research Center of Nanjing University, Nanjing 211800 (China); Zhou, Hui, E-mail: hardhui@gmail.com [Department of Occupational and Environmental Health Sciences, School of Public Health, Peking University, 100191 (China)

    2017-05-01

    Background: Atmospheric ultrafine particles (UFPs) and pesticide rotenone were considered as potential environmental risk factors for Parkinson's disease (PD). However, whether and how UFPs alone and in combination with rotenone affect the pathogenesis of PD remains largely unknown. Methods: Ultrafine carbon black (ufCB, a surrogate of UFPs) and rotenone were used individually or in combination to determine their roles in chronic dopaminergic (DA) loss in neuron-glia, and neuron-enriched, mix-glia cultures. Immunochemistry using antibody against tyrosine hydroxylase was performed to detect DA neuronal loss. Measurement of extracellular superoxide and intracellular reactive oxygen species (ROS) were performed to examine activation of NADPH oxidase. Genetic deletion and pharmacological inhibition of NADPH oxidase and MAC-1 receptor in microglia were employed to examine their role in DA neuronal loss triggered by ufCB and rotenone. Results: In rodent midbrain neuron-glia cultures, ufCB and rotenone alone caused neuronal death in a dose-dependent manner. In particularly, ufCB at doses of 50 and 100 μg/cm{sup 2} induced significant loss of DA neurons. More importantly, nontoxic doses of ufCB (10 μg/cm{sup 2}) and rotenone (2 nM) induced synergistic toxicity to DA neurons. Microglial activation was essential in this process. Furthermore, superoxide production from microglial NADPH oxidase was critical in ufCB/rotenone-induced neurotoxicity. Studies in mix-glia cultures showed that ufCB treatment activated microglial NADPH oxidase to induce superoxide production. Firstly, ufCB enhanced the expression of NADPH oxidase subunits (gp91{sup phox}, p47{sup phox} and p40{sup phox}); secondly, ufCB was recognized by microglial surface MAC-1 receptor and consequently promoted rotenone-induced p47{sup phox} and p67{sup phox} translocation assembling active NADPH oxidase. Conclusion: ufCB and rotenone worked in synergy to activate NADPH oxidase in microglia, leading to

  19. Simulation of diffusion-induced stress using reconstructed electrodes particle structures generated by micro/nano-CT

    International Nuclear Information System (INIS)

    Lim, Cheolwoong; Yan Bo; Yin Leilei; Zhu Likun

    2012-01-01

    Highlights: ► The microstructure of LIB electrodes was obtained by X-ray micro/nano-CT. ► We studied diffusion-induced stresses based on realistic 3D microstructures. ► Stresses depend on geometric characteristics of electrode particle. ► Stresses in a real particle are much higher than those in a spherical particle. - Abstract: Lithium ion batteries experience diffusion-induced stresses during charge and discharge processes which can cause electrode failure in the form of fracture. Previous diffusion-induced stress models and simulations are mainly based on simple active material particle structures, such as spheres and ellipsoids. However, the simple structure model cannot reveal the stress development in a real complex lithium ion battery electrode. In this paper, we studied the diffusion-induced stresses numerically based on a realistic morphology of reconstructed particles during the lithium ion intercalation process. The morphology of negative and positive active materials of a lithium ion battery was determined using X-ray micro/nano computed tomography technology. Diffusion-induced stresses were simulated at different C rates under galvonostatic conditions and compared with spherical particles. The simulation results show that the intercalation stresses of particles depend on their geometric characteristics. The highest von Mises stress and Tresca stress in a real particle are several times higher than the stresses in a spherical particle with the same volume.

  20. Particle creation phenomenology, Dirac sea and the induced Weyl and Einstein-dilaton gravity

    Energy Technology Data Exchange (ETDEWEB)

    Berezin, V.A.; Dokuchaev, V.I.; Eroshenko, Yu.N., E-mail: berezin@inr.ac.ru, E-mail: dokuchaev@inr.ac.ru, E-mail: eroshenko@inr.ac.ru [Institute for Nuclear Research, Russian Academy of Sciences, 60th October Anniversary Prospect 7a, 117312 Moscow (Russian Federation)

    2017-01-01

    We constructed the conformally invariant model for scalar particle creation induced by strong gravitational fields. Starting from the 'usual' hydrodynamical description of the particle motion written in the Eulerian coordinates we substituted the particle number conservation law (which enters the formalism) by 'the particle creation law', proportional to the square of the Weyl tensor (following the famous result by Ya.B. Zel'dovich and A.A. Starobinsky). Then, demanding the conformal invariance of the whole dynamical system, we have got both the (Weyl)-conformal gravity and the Einstein-Hilbert gravity action integral with dilaton field. Thus, we obtained something like the induced gravity suggested first by A.D. Sakharov. It is shown that the resulting system is self-consistent. We considered also the vacuum equations. It is shown that, beside the 'empty vacuum', there may exist the 'dynamical vacuum', which is nothing more but the Dirac sea. The latter is described by the unexpectedly elegant equation which includes both the Bach and Einstein tensors and the cosmological terms.

  1. The sustained-release behavior and in vitro and in vivo transfection of pEGFP-loaded core-shell-structured chitosan-based composite particles

    Directory of Open Access Journals (Sweden)

    Wang Y

    2014-10-01

    Full Text Available Yun Wang,1 Fu-xing Lin,2 Yu Zhao,1 Mo-zhen Wang,2 Xue-wu Ge,2 Zheng-xing Gong,1 Dan-dan Bao,1 Yu-fang Gu1 1Department of Plastic Surgery, First Affiliated Hospital of Anhui Medical University, 2CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui, People’s Republic of China Abstract: Novel submicron core-shell-structured chitosan-based composite particles ­encapsulated with enhanced green fluorescent protein plasmids (pEGFP were prepared by complex coacervation method. The core was pEGFP-loaded thiolated N-alkylated chitosan (TACS and the shell was pH- and temperature-responsive hydroxybutyl chitosan (HBC. pEGFP-loaded TACS-HBC composite particles were spherical, and had a mean diameter of approximately 120 nm, as measured by transmission electron microscopy and particle size analyzer. pEGFP showed sustained release in vitro for >15 days. Furthermore, in vitro transfection in human embryonic kidney 293T and human cervix epithelial cells, and in vivo transfection in mice skeletal muscle of loaded pEGFP, were investigated. Results showed that the expression of loaded pEGFP, both in vitro and in vivo, was slow but could be sustained over a long period. pEGFP expression in mice skeletal muscle was sustained for >60 days. This work indicates that these submicron core-shell-structured chitosan-based composite particles could potentially be used as a gene vector for in vivo controlled gene transfection. Keywords: gene therapy, gene transfection, hydroxybutyl chitosan, thiolated N-alkylated chitosan, pEGFP, complex coacervation

  2. SCALP: Scintillating ionization chamber for ALPha particle production in neutron induced reactions

    Science.gov (United States)

    Galhaut, B.; Durand, D.; Lecolley, F. R.; Ledoux, X.; Lehaut, G.; Manduci, L.; Mary, P.

    2017-09-01

    The SCALP collaboration has the ambition to build a scintillating ionization chamber in order to study and measure the cross section of the α-particle production in neutron induced reactions. More specifically on 16O and 19F targets. Using the deposited energy (ionization) and the time of flight measurement (scintillation) with a great accuracy, all the nuclear reaction taking part on this project will be identify.

  3. Particle induced X-ray emission for quantitative trace-element analysis using the Eindhoven cyclotron

    International Nuclear Information System (INIS)

    Kivits, H.

    1980-01-01

    Development of a multi-elemental trace analysis technique using PIXE (Particle Induced X-ray Emission), was started almost five years ago at the Eindhoven University of Technology, in the Cyclotron Applications Group of the Physics Department. The aim of the work presented is to improve the quantitative aspects of trace-element analysis with PIXE, as well as versatility, speed and simplicity. (Auth.)

  4. Influence of resistivity on energetic trapped particle-induced internal kink modes

    International Nuclear Information System (INIS)

    Biglari, H.; Chen, L.

    1986-01-01

    The influence of resistivity on energetic trapped particle-induced internal kink modes, dubbed ''fishbones'' in the literature, is explored. A general dispersion relation, which recovers the ideal theory in its appropriate limit, is derived and analyzed. An important implication of the theory for present generation fusion devices such as the Joint European Torus [Plasma Physics and Controlled Nuclear Fusion Research (IAEA, London, 1984), Vol I, p.11] is that they will be stable to fishbone activity

  5. Physical properties and structure of fine core-shell particles used as packing materials for chromatography Relationships between particle characteristics and column performance.

    Science.gov (United States)

    Gritti, Fabrice; Leonardis, Irene; Abia, Jude; Guiochon, Georges

    2010-06-11

    The recent development of new brands of packing materials made of fine porous-shell particles, e.g., Halo and Kinetex, has brought great improvements in potential column efficiency, demanding considerable progress in the design of chromatographic instruments. Columns packed with Halo and Kinetex particles provide minimum values of their reduced plate heights of nearly 1.5 and 1.2, respectively. These packing materials have physical properties that set them apart from conventional porous particles. The kinetic performance of 4.6mm I.D. columns packed with these two new materials is analyzed based on the results of a series of nine independent and complementary experiments: low-temperature nitrogen adsorption (LTNA), scanning electron microscopy (SEM), inverse size-exclusion chromatography (ISEC), Coulter counter particle size distributions, pycnometry, height equivalent to a theoretical plate (HETP), peak parking method (PP), total pore blocking method (TPB), and local electrochemical detection across the column exit section (LED). The results of this work establish links between the physical properties of these superficially porous particles and the excellent kinetic performance of columns packed with them. It clarifies the fundamental origin of the difference in the chromatographic performances of the Halo and the Kinetex columns. Copyright 2010 Elsevier B.V. All rights reserved.

  6. Particles from wood smoke and traffic induce differential pro-inflammatory response patterns in co-cultures

    International Nuclear Information System (INIS)

    Kocbach, Anette; Herseth, Jan Inge; Lag, Marit; Refsnes, Magne; Schwarze, Per E.

    2008-01-01

    The inflammatory potential of particles from wood smoke and traffic has not been well elucidated. In this study, a contact co-culture of monocytes and pneumocytes was exposed to 10-40 μg/cm 2 of particles from wood smoke and traffic for 12, 40 and 64 h to determine their influence on pro-inflammatory cytokine release (TNF-α, IL-1, IL-6, IL-8) and viability. To investigate the role of organic constituents in cytokine release the response to particles, their organic extracts and the washed particles were compared. Antagonists were used to investigate source-dependent differences in intercellular signalling (TNF-α, IL-1). The cytotoxicity was low after exposure to particles from both sources. However, wood smoke, and to a lesser degree traffic-derived particles, induced a reduction in cell number, which was associated with the organic fraction. The release of pro-inflammatory cytokines was similar for both sources after 12 h, but traffic induced a greater release than wood smoke particles with increasing exposure time. The organic fraction accounted for the majority of the cytokine release induced by wood smoke, whereas the washed traffic particles induced a stronger response than the corresponding organic extract. TNF-α and IL-1 antagonists reduced the release of IL-8 induced by particles from both sources. In contrast, the IL-6 release was only reduced by the IL-1 antagonist during exposure to traffic-derived particles. In summary, particles from wood smoke and traffic induced differential pro-inflammatory response patterns with respect to cytokine release and cell number. Moreover, the influence of the organic particle fraction and intercellular signalling on the pro-inflammatory response seemed to be source-dependent

  7. Detection of vortex-core dynamics using current-induced self-bistable rectifying effect

    International Nuclear Information System (INIS)

    Goto, M; Hata, H; Yamaguchi, A; Miyajima, H; Nozaki, Y; Nakatani, Y; Yamaoka, T

    2011-01-01

    A magnetic vortex core confined in a micron-scale magnetic disk is resonantly excited by spin-polarized radio-frequency (rf) current and rf field. We show that rectifying voltage spectra caused by the vortex core resonance is dependent on the core polarity. Rectifying voltage spectra are given by the superposition of the polarity-dependent term and the polarity-independent term. The sign of the polarity-dependent rectifying voltage reverses when the sign of polarity P or external field H is reversed. This experimental result can be explained by the anisotropic magnetoresistance effect caused by the vortex core motion.

  8. HCV core protein induces hepatic lipid accumulation by activating SREBP1 and PPARγ

    International Nuclear Information System (INIS)

    Kim, Kook Hwan; Hong, Sung Pyo; Kim, KyeongJin; Park, Min Jung; Kim, Kwang Jin; Cheong, JaeHun

    2007-01-01

    Hepatic steatosis is a common feature in patients with chronic hepatitis C virus (HCV) infection. HCV core protein plays an important role in the development of hepatic steatosis in HCV infection. Because SREBP1 (sterol regulatory element binding protein 1) and PPARγ (peroxisome proliferators-activated receptor γ) are involved in the regulation of lipid metabolism of hepatocyte, we sought to determine whether HCV core protein may impair the expression and activity of SREBP1 and PPARγ. In this study, it was demonstrated that HCV core protein increases the gene expression of SREBP1 not only in Chang liver, Huh7, and HepG2 cells transiently transfected with HCV core protein expression plasmid, but also in Chang liver-core stable cells. Furthermore, HCV core protein enhanced the transcriptional activity of SREBP1. In addition, HCV core protein elevated PPARγ transcriptional activity. However, HCV core protein had no effect on PPARγ gene expression. Finally, we showed that HCV core protein stimulates the genes expression of lipogenic enzyme and fatty acid uptake associated protein. Therefore, our finding provides a new insight into the mechanism of hepatic steatosis by HCV infection

  9. Neuroprotective effect of curcumin-loaded lactoferrin nano particles against rotenone induced neurotoxicity.

    Science.gov (United States)

    Bollimpelli, V Satish; Kumar, Prashant; Kumari, Sonali; Kondapi, Anand K

    2016-05-01

    Curcumin is known to have neuroprotective role and possess antioxidant, anti-inflammatory activities. Rotenone, a flavonoid induced neurotoxicity in dopaminergic cells is being widely studied in Parkinson's Disease (PD) research. In the present study, curcumin loaded lactoferrin nano particles prepared by sol-oil chemistry were used to protect dopaminergic cell line SK-N-SH against rotenone induced neurotoxicity. These curcumin loaded nano particles were of 43-60 nm diameter size and around 100 nm hydrodynamic size as assessed by transmission electron microscopy, atomic force microscopy and dynamic light scattering analysis respectively. The encapsulation efficiency was 61.3% ± 2.4%. Cellular uptake of curcumin through these nano particles was confirmed by confocal imaging and spectrofluorimetric analysis. The curcumin loaded lactoferrin nanoparticles showed greater intracellular drug uptake, sustained retention and greater neuroprotection than soluble counterpart. Neuroprotective activity was characterized through viability assays and by estimating ROS levels. Furthermore rotenone induced PD like features were characterized by decrease in tyrosine hydroxylase expression and increase in α-synuclein expression. Taken together curcumin loaded lactoferrin nanoparticles could be a promising drug delivery strategy against neurotoxicity in dopaminergic neurons. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Folic acid-functionalized magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell composite particles: synthesis and application in drug release.

    Science.gov (United States)

    Yang, Dandan; Wei, Kaiwei; Liu, Qi; Yang, Yong; Guo, Xue; Rong, Hongren; Cheng, Mei-Ling; Wang, Guoxiu

    2013-07-01

    A drug delivery system was designed by deliberately combining the useful functions into one entity, which was composed of magnetic ZnFe2O4 hollow microsphere as the core, and mesoporous silica with folic acid molecules as the outer shell. Amine groups coated magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell (MZHM-MSS-NH2) composite particles were first synthesized by a one-pot direct co-condensation method. Subsequently a novel kind of folic acid-functionalized magnetic ZnFe2O4 hollow microsphere core/mesoporous silica shell (MZHM-MSS-NHFA) composite particles were synthesized by conjugating folic acid as targeted molecule to MZHM-MSS-NH2. Ibuprofen, a well-known antiphlogistic drug, was used as a model drug to assess the loading and releasing behavior of the composite microspheres. The results show that the MZHM-MSS-NHFA system has the higher capacity of drug storage and good sustained drug-release property. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Photon hormesis deactivates alpha-particle induced bystander effects between zebrafish embryos

    International Nuclear Information System (INIS)

    Ng, C.Y.P.; Cheng, S.H.; Yu, K.N.

    2017-01-01

    In the present work, we studied the effects of low-dose X-ray photons on the alpha-particle induced bystander effects between embryos of the zebrafish, Danio rerio. The effects on the naive whole embryos were studied through quantification of apoptotic signals (amounts of cells undergoing apoptosis) at 24 h post fertilization (hpf) using vital dye acridine orange staining, followed by counting the stained cells under a fluorescent microscope. We report data showing that embryos at 5 hpf subjected to a 4.4 mGy alpha-particle irradiation could release a stress signal into the medium, which could induce bystander effect in partnered naive embryos sharing the same medium. We also report that the bystander effect was deactivated when the irradiated embryos were subjected to a concomitant irradiation of 10 or 14 mGy of X-rays, but no such deactivation was achieved if the concomitant X-ray dose dropped to 2.5 or 5 mGy. In the present study, the significant drop in the amount of apoptotic signals on the embryos having received 4.4 mGy alpha particles together X-rays irradiation from 2.5 or 5 mGy to 10 or 14 mGy, together with the deactivation of RIBE with concomitant irradiation of 10 or 14 mGy of X-rays supported the participation of photon hormesis with an onset dose between 5 and 10 mGy, which might lead to removal of aberrant cells through early apoptosis or induction of high-fidelity DNA repair. As we found that photons and alpha particles could have opposite biological effects when these were simultaneously irradiated onto living organisms, these ionizing radiations could be viewed as two different environmental stressors, and the resultant effects could be regarded as multiple stressor effects. The present work presented the first study on a multiple stressor effect which occurred on bystander organisms. In other words, this was a non-targeted multiple stressor effect. The photon hormesis could also explain some failed attempts to observe neutron-induced bystander

  12. Synthesis of sol–gel silica particles in reverse micelles with mixed-solvent polar cores: tailoring nanoreactor structure and properties

    Energy Technology Data Exchange (ETDEWEB)

    Bürglová, Kristýna; Hlaváč, Jan [Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry (Czech Republic); Bartlett, John R., E-mail: jbartlett@usc.edu.au [University of the Sunshine Coast, Faculty of Science, Health, Education and Engineering (Australia)

    2015-07-15

    In this paper, we describe a new approach for producing metal oxide nano- and microparticles via sol–gel processing in confined media (sodium bis(2-ethylhexyl)sulfosuccinate reverse micelles), in which the chemical and physical properties of the polar aqueous core of the reverse micelles are modulated by the inclusion of a second polar co-solvent. The co-solvents were selected for their capacity to solubilise compounds with low water solubility and included dimethylsulfoxide, dimethylformamide, ethylene glycol, n-propanol, dimethylacetamide and N-methylpyrrolidone. A broad range of processing conditions across the sodium bis(2-ethylhexyl)sulfosuccinate/cyclohexane/water phase diagram were identified that are suitable for preparing particles with dimensions <50 to >500 nm. In contrast, only a relatively narrow range of processing conditions were suitable for preparing such particles in the absence of the co-solvents, highlighting the role of the co-solvent in modulating the properties of the polar core of the reverse micelles. A mechanism is proposed that links the interactions between the various reactive sites on the polar head group of the surfactant and the co-solvent to the nucleation and growth of the particles.

  13. Mechanical behaviors of the dispersion nuclear fuel plates induced by fuel particle swelling and thermal effect II: Effects of variations of the fuel particle diameters

    International Nuclear Information System (INIS)

    Ding Shurong; Wang Qiming; Huo Yongzhong

    2010-01-01

    In order to predict the irradiation mechanical behaviors of plate-type dispersion nuclear fuel elements, the total burnup is divided into two stages: the initial stage and the increasing stage. At the initial stage, the thermal effects induced by the high temperature differences between the operation temperatures and the room temperature are mainly considered; and at the increasing stage, the intense mechanical interactions between the fuel particles and the matrix due to the irradiation swelling of fuel particles are focused on. The large-deformation thermo-elasto-plasticity finite element analysis is performed to evaluate the effects of particle diameters on the in-pile mechanical behaviors of fuel elements. The research results indicate that: (1) the maximum Mises stresses and equivalent plastic strains at the matrix increase with the fuel particle diameters; the effects of particle diameters on the maximum first principal stresses vary with burnup, and the considered case with the largest particle diameter holds the maximum values all along; (2) at the cladding near the interface between the fuel meat and the cladding, the Mises stresses and the first principal stresses undergo major changes with increasing burnup, and different variations exist for different particle diameter cases; (3) the maximum Mises stresses at the fuel particles rise with the particle diameters.

  14. Brain signaling and behavioral responses induced by exposure to (56)Fe-particle radiation

    Science.gov (United States)

    Denisova, N. A.; Shukitt-Hale, B.; Rabin, B. M.; Joseph, J. A.

    2002-01-01

    Previous experiments have demonstrated that exposure to 56Fe-particle irradiation (1.5 Gy, 1 GeV) produced aging-like accelerations in neuronal and behavioral deficits. Astronauts on long-term space flights will be exposed to similar heavy-particle radiations that might have similar deleterious effects on neuronal signaling and cognitive behavior. Therefore, the present study evaluated whether radiation-induced spatial learning and memory behavioral deficits are associated with region-specific brain signaling deficits by measuring signaling molecules previously found to be essential for behavior [pre-synaptic vesicle proteins, synaptobrevin and synaptophysin, and protein kinases, calcium-dependent PRKCs (also known as PKCs) and PRKA (PRKA RIIbeta)]. The results demonstrated a significant radiation-induced increase in reference memory errors. The increases in reference memory errors were significantly negatively correlated with striatal synaptobrevin and frontal cortical synaptophysin expression. Both synaptophysin and synaptobrevin are synaptic vesicle proteins that are important in cognition. Striatal PRKA, a memory signaling molecule, was also significantly negatively correlated with reference memory errors. Overall, our findings suggest that radiation-induced pre-synaptic facilitation may contribute to some previously reported radiation-induced decrease in striatal dopamine release and for the disruption of the central dopaminergic system integrity and dopamine-mediated behavior.

  15. Toll-like receptors-2 and 4 are overexpressed in an experimental model of particle-induced osteolysis.

    Science.gov (United States)

    Valladares, Roberto D; Nich, Christophe; Zwingenberger, Stefan; Li, Chenguang; Swank, Katherine R; Gibon, Emmanuel; Rao, Allison J; Yao, Zhenyu; Goodman, Stuart B

    2014-09-01

    Aseptic loosening secondary to particle-associated periprosthetic osteolysis remains a major cause of failure of total joint replacements (TJR) in the mid- and long term. As sentinels of the innate immune system, macrophages are central to the recognition and initiation of the inflammatory cascade, which results in the activation of bone resorbing osteoclasts. Toll-like receptors (TLRs) are involved in the recognition of pathogen-associated molecular patterns and danger-associated molecular patterns. Experimentally, polymethylmethacrylate and polyethylene (PE) particles have been shown to activate macrophages via the TLR pathway. The specific TLRs involved in PE particle-induced osteolysis remain largely unknown. We hypothesized that TLR-2, -4, and -9 mediated responses play a critical role in the development of PE wear particle-induced osteolysis in the murine calvarium model. To test this hypothesis, we first demonstrated that PE particles caused observable osteolysis, visible by microCT and bone histomorphometry when the particles were applied to the calvarium of C57BL/6 mice. The number of TRAP positive osteoclasts was significantly greater in the PE-treated group when compared to the control group without particles. Finally, using immunohistochemistry, TLR-2 and TLR-4 were highly expressed in PE particle-induced osteolytic lesions, whereas TLR-9 was downregulated. TLR-2 and -4 may represent novel therapeutic targets for prevention of wear particle-induced osteolysis and accompanying TJR failure. © 2013 Wiley Periodicals, Inc.

  16. Rotation of a Spherical Particle with Electrical Dipole Moment Induced by Steady Irradiation in a Static Electric Field

    Science.gov (United States)

    Grachev, A. I.

    2018-04-01

    Rotation of a spherical particle in a static electric field and under steady irradiation that induces an electric dipole moment in the particle is studied for the first time. Along with the general treatment of the phenomenon, we analyze possible mechanisms underlying the photoinduction of dipole moment in the particle. Estimations of the angular velocity and the power expended by the rotating particle are provided. The indicated characteristics reach their maximum values if the size of particles is within the range of 10 nm to 10 μm.

  17. Synthesis of core-shell hematite (α-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity

    Science.gov (United States)

    Tadic, Marin; Kopanja, Lazar; Panjan, Matjaz; Kralj, Slavko; Nikodinovic-Runic, Jasmina; Stojanovic, Zoran

    2017-05-01

    Hematite core-shell nanoparticles with plate-like morphology were synthesized using a one-step hydrothermal synthesis. An XRPD analysis indicates that the sample consist of single-phase α-Fe2O3 nanoparticles. SEM and TEM measurements show that the hematite sample is composed of uniform core-shell nanoplates with 10-20 nm thickness, 80-100 nm landscape dimensions (aspect ratio ∼5) and 3-4 nm thickness of the surface shells. We used computational methods for the quantitative analysis of the core-shell particle structure and circularity shape descriptor for the quantitative shape analysis of the nanoparticles from TEM micrographs. The calculated results indicated that a percentage of the shell area in the nanoparticle area (share [%]) is significant. The determined values of circularity in the perpendicular and oblique perspective clearly show shape anisotropy of the nanoplates. The magnetic properties revealed the ferromagnetic-like properties at room temperature with high coercivity HC = 2340 Oe, pointing to the shape and surface effects. These results signify core-shell hematite nanoparticles' for practical applications in magnetic devices. The synthesized hematite plate-like nanoparticles exhibit low cytotoxicity levels on the human lung fibroblasts (MRC5) cell line demonstrating the safe use of these nanoparticles for biomedical applications.

  18. Differential Requirements for T Cells in Viruslike Particle- and Rotavirus-Induced Protective Immunity▿

    Science.gov (United States)

    Blutt, Sarah E.; Warfield, Kelly L.; Estes, Mary K.; Conner, Margaret E.

    2008-01-01

    Correlates of protection from rotavirus infection are controversial. We compared the roles of B and T lymphocytes in protective immunity induced either by intranasally administered nonreplicating viruslike particles or inactivated virus or by orally administered murine rotavirus. We found that protection induced by nonreplicating vaccines requires CD4+ T cells and CD40/CD40L. In contrast, T cells were not required for short-term protective immunity induced by infection, but both T-cell-dependent and -independent mechanisms contributed to long-term maintenance of protection. Our findings indicate that more than one marker of protective immunity exists and that these markers depend on the vaccine that is administered. PMID:18184712

  19. Schisantherin A suppresses osteoclast formation and wear particle-induced osteolysis via modulating RANKL signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi; Zhang, Qing; Shen, Yi; Chen, Xia; Zhou, Feng; Peng, Dan, E-mail: xyeypd@163.com

    2014-07-04

    Highlights: • Schisantherin A suppresses osteoclasts formation and function in vitro. • Schisantherin A impairs RANKL signaling pathway. • Schisantherin A suppresses osteolysis in vivo. • Schisantherin A may be used for treating osteoclast related diseases. - Abstract: Receptor activator of NF-κB ligand (RANKL) plays critical role in osteoclastogenesis. Targeting RANKL signaling pathways has been a promising strategy for treating osteoclast related bone diseases such as osteoporosis and aseptic prosthetic loosening. Schisantherin A (SA), a dibenzocyclooctadiene lignan isolated from the fruit of Schisandra sphenanthera, has been used as an antitussive, tonic, and sedative agent, but its effect on osteoclasts has been hitherto unknown. In the present study, SA was found to inhibit RANKL-induced osteoclast formation and bone resorption. The osteoclastic specific marker genes induced by RANKL including c-Src, SA inhibited OSCAR, cathepsin K and TRAP in a dose dependent manner. Further signal transduction studies revealed that SA down-regulate RANKL-induced nuclear factor-kappaB (NF-κB) signaling activation by suppressing the phosphorylation and degradation of IκBα, and subsequently preventing the NF-κB transcriptional activity. Moreover, SA also decreased the RANKL-induced MAPKs signaling pathway, including JNK and ERK1/2 posphorylation while had no obvious effects on p38 activation. Finally, SA suppressed the NF-κB and MAPKs subsequent gene expression of NFATc1 and c-Fos. In vivo studies, SA inhibited osteoclast function and exhibited bone protection effect in wear-particle-induced bone erosion model. Taken together, SA could attenuate osteoclast formation and wear particle-induced osteolysis by mediating RANKL signaling pathways. These data indicated that SA is a promising therapeutic natural compound for the treatment of osteoclast-related prosthesis loosening.

  20. Detection of tire tread particles using laser-induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Prochazka, David; Bilík, Martin; Prochazková, Petra; Klus, Jakub; Pořízka, Pavel; Novotný, Jan; Novotný, Karel; Ticová, Barbora; Bradáč, Albert; Semela, Marek

    2015-01-01

    The objective of this paper is a study of the potential of laser induced breakdown spectroscopy (LIBS) for detection of tire tread particles. Tire tread particles may represent pollutants; simultaneously, it is potentially possible to exploit detection of tire tread particles for identification of optically imperceptible braking tracks at locations of road accidents. The paper describes the general composition of tire treads and selection of an element suitable for detection using the LIBS method. Subsequently, the applicable spectral line is selected considering interferences with lines of elements that might be present together with the detected particles, and optimization of measurement parameters such as incident laser energy, gate delay and gate width is performed. In order to eliminate the matrix effect, measurements were performed using 4 types of tires manufactured by 3 different producers. An adhesive tape was used as a sample carrier. The most suitable adhesive tape was selected from 5 commonly available tapes, on the basis of their respective LIBS spectra. Calibration standards, i.e. an adhesive tape with different area content of tire tread particles, were prepared for the selected tire. A calibration line was created on the basis of the aforementioned calibration standards. The linear section of this line was used for determination of the detection limit value applicable to the selected tire. Considering the insignificant influence of matrix of various types of tires, it is possible to make a simple recalculation of the detection limit value on the basis of zinc content in a specific tire. - Highlights: • LIBS experimental measurement parameters for tire tread particles were optimize. • Calibration curve was prepared. • Limit of detection was determined

  1. Detection of tire tread particles using laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Prochazka, David, E-mail: prochazka.d@fme.vutbr.cz [Brno University of Technology, Institute of Physical Engineering, Technická 2, 616 00 Brno (Czech Republic); Brno University of Technology, Central European Institute of Technology, Technická 3058/10, CZ-616 00 Brno (Czech Republic); Bilík, Martin [Brno University of Technology, Institute of Forensic Engineering, Údolní 244/53, 602 00 Brno (Czech Republic); Prochazková, Petra [Masaryk University, Faculty of Science, Department of Chemistry, Kamenice 735/5, 625 00 Brno (Czech Republic); Klus, Jakub; Pořízka, Pavel; Novotný, Jan [Brno University of Technology, Central European Institute of Technology, Technická 3058/10, CZ-616 00 Brno (Czech Republic); Novotný, Karel [Masaryk University, Faculty of Science, Department of Chemistry, Kamenice 735/5, 625 00 Brno (Czech Republic); Brno University of Technology, Central European Institute of Technology, Technická 3058/10, CZ-616 00 Brno (Czech Republic); Ticová, Barbora [Masaryk University, Faculty of Science, Department of Chemistry, Kamenice 735/5, 625 00 Brno (Czech Republic); Bradáč, Albert; Semela, Marek [Brno University of Technology, Institute of Forensic Engineering, Údolní 244/53, 602 00 Brno (Czech Republic); and others

    2015-06-01

    The objective of this paper is a study of the potential of laser induced breakdown spectroscopy (LIBS) for detection of tire tread particles. Tire tread particles may represent pollutants; simultaneously, it is potentially possible to exploit detection of tire tread particles for identification of optically imperceptible braking tracks at locations of road accidents. The paper describes the general composition of tire treads and selection of an element suitable for detection using the LIBS method. Subsequently, the applicable spectral line is selected considering interferences with lines of elements that might be present together with the detected particles, and optimization of measurement parameters such as incident laser energy, gate delay and gate width is performed. In order to eliminate the matrix effect, measurements were performed using 4 types of tires manufactured by 3 different producers. An adhesive tape was used as a sample carrier. The most suitable adhesive tape was selected from 5 commonly available tapes, on the basis of their respective LIBS spectra. Calibration standards, i.e. an adhesive tape with different area content of tire tread particles, were prepared for the selected tire. A calibration line was created on the basis of the aforementioned calibration standards. The linear section of this line was used for determination of the detection limit value applicable to the selected tire. Considering the insignificant influence of matrix of various types of tires, it is possible to make a simple recalculation of the detection limit value on the basis of zinc content in a specific tire. - Highlights: • LIBS experimental measurement parameters for tire tread particles were optimize. • Calibration curve was prepared. • Limit of detection was determined.

  2. Induced luminescence by charged particles on gaseous, liquid and solid argon

    International Nuclear Information System (INIS)

    Carvalho Torres, M.J.

    1980-01-01

    A spectral and a kinetic study of the scintillation induced by β and α particles in gaseous, liquid and solid argon have been made in the wavelength region comprised between 1100 and 3000A. The radiative lifetimes and some spectroscopic parameters of the lowest dimer states ( 1 Σ + sub(u) and 3 Σ + sub(u)) have been determined: tau 0 ( 1 Σ + sub(u)) = 4.2ns; tau 0 ( 3 Σ + sub(u)) = 3.1μs; ΔE( 1 Σ + sub(u)- 3 Σ + sub(u)) = 52 meV; hω = 230 cm -1 . A non radiative de-excitation rate of the 3 Σ + sub(u) state has been measured: approximately 2x10 -17 cm 3 s -1 . By applying an electric field the contribution of the electron-ion recombination mechanism to the gaseous argon scintillation is studied. For condensed argon, the dependence of the ratio between the fluorescence and the phosphorescence intensities on the ionisation power of the impinging particle is verified. The continuum which extends from 1600 to 2900A and that is present only in the gas phase spectra, is ascribed to the radiative de-excitation of molecular ions. A time resolved study of the luminescence of high pressure (1-15atm) argon excited by a pulsed electric discharge has also been performed and is compared with that of the scintillation induced by nuclear particles [fr

  3. Three-dimensional gyrokinetic particle-in-cell simulation of plasmas on a massively parallel computer: Final report on LDRD Core Competency Project, FY 1991--FY 1993

    International Nuclear Information System (INIS)

    Byers, J.A.; Williams, T.J.; Cohen, B.I.; Dimits, A.M.

    1994-01-01

    One of the programs of the Magnetic fusion Energy (MFE) Theory and computations Program is studying the anomalous transport of thermal energy across the field lines in the core of a tokamak. We use the method of gyrokinetic particle-in-cell simulation in this study. For this LDRD project we employed massively parallel processing, new algorithms, and new algorithms, and new formal techniques to improve this research. Specifically, we sought to take steps toward: researching experimentally-relevant parameters in our simulations, learning parallel computing to have as a resource for our group, and achieving a 100 x speedup over our starting-point Cray2 simulation code's performance

  4. Polyhexamethylene guanidine phosphate aerosol particles induce pulmonary inflammatory and fibrotic responses.

    Science.gov (United States)

    Kim, Ha Ryong; Lee, Kyuhong; Park, Chang We; Song, Jeong Ah; Shin, Da Young; Park, Yong Joo; Chung, Kyu Hyuck

    2016-03-01

    Polyhexamethylene guanidine (PHMG) phosphate was used as a disinfectant for the prevention of microorganism growth in humidifiers, without recognizing that a change of exposure route might cause significant health effects. Epidemiological studies reported that the use of humidifier disinfectant containing PHMG-phosphate can provoke pulmonary fibrosis. However, the pulmonary toxicity of PHMG-phosphate aerosol particles is unknown yet. This study aimed to elucidate the toxicological relationship between PHMG-phosphate aerosol particles and pulmonary fibrosis. An in vivo nose-only exposure system and an in vitro air-liquid interface (ALI) co-culture model were applied to confirm whether PHMG-phosphate induces inflammatory and fibrotic responses in the respiratory tract. Seven-week-old male Sprague-Dawley rats were exposed to PHMG-phosphate aerosol particles for 3 weeks and recovered for 3 weeks in a nose-only exposure chamber. In addition, three human lung cells (Calu-3, differentiated THP-1 and HMC-1 cells) were cultured at ALI condition for 12 days and were treated with PHMG-phosphate at set concentrations and times. The reactive oxygen species (ROS) generation, airway barrier injuries and inflammatory and fibrotic responses were evaluated in vivo and in vitro. The rats exposed to PHMG-phosphate aerosol particles in nanometer size showed pulmonary inflammation and fibrosis including inflammatory cytokines and fibronectin mRNA increase, as well as histopathological changes. In addition, PHMG-phosphate triggered the ROS generation, airway barrier injuries and inflammatory responses in a bronchial ALI co-culture model. Those results demonstrated that PHMG-phosphate aerosol particles cause pulmonary inflammatory and fibrotic responses. All features of fibrogenesis by PHMG-phosphate aerosol particles closely resembled the pathology of fibrosis that was reported in epidemiological studies. Finally, we expected that PHMG-phosphate infiltrated into the lungs in the form of

  5. Towards quantitative analysis of core-shell catalyst nano-particles by aberration corrected high angle annular dark field STEM and EDX

    International Nuclear Information System (INIS)

    Haibo, E; Nellist, P D; Lozano-Perez, S; Ozkaya, D

    2010-01-01

    Core-shell structured heterogeneous catalyst nano-particles offer the promise of more efficient precious metal usage and also novel functionalities but are as yet poorly characterised due to large compositional variations over short ranges. High angle annular dark field detector in a scanning transmission electron microscope is frequently used to image at high resolution because of its Z-contrast and incoherent imaging process, but generally little attention is paid to quantification. Energy dispersive X-ray analysis provides information on thickness and chemical composition and, used in conjunction with HAADF-STEM, aids interpretation of imaged nano-particles. We present important calibrations and initial data for truly quantitative high resolution analysis.

  6. Particle-induced bit errors in high performance fiber optic data links for satellite data management

    International Nuclear Information System (INIS)

    Marshall, P.W.; Carts, M.A.; Dale, C.J.; LaBel, K.A.

    1994-01-01

    Experimental test methods and analysis tools are demonstrated to assess particle-induced bit errors on fiber optic link receivers for satellites. Susceptibility to direct ionization from low LET particles is quantified by analyzing proton and helium ion data as a function of particle LET. Existing single event analysis approaches are shown to apply, with appropriate modifications, to the regime of temporally (rather than spatially) distributed bits, even though the sensitivity to single events exceeds conventional memory technologies by orders of magnitude. The cross-section LET dependence follows a Weibull distribution at data rates from 200 to 1,000 Mbps and at various incident optical power levels. The LET threshold for errors is shown, through both experiment and modeling, to be 0 in all cases. The error cross-section exhibits a strong inverse dependence on received optical power in the LET range where most orbital single events would occur, thus indicating that errors can be minimized by operating links with higher incident optical power. Also, an analytic model is described which incorporates the appropriate physical characteristics of the link as well as the optical and receiver electrical characteristics. Results indicate appropriate steps to assure suitable link performance even in severe particle orbits

  7. Atomic collisions by neutrons-induced charged particles in water, protein and nucleic acid

    International Nuclear Information System (INIS)

    Bergman, R.

    1976-01-01

    The action of slow charged particles is peculiar in that atomic collisions are commonly invlolved. In atomic collisions, which are rare events when fast particles interact with matter, displacement of atoms and chemical bond-breakage is possible. Sufficiently energetic neutrons generate charged recoil particles in matter. Some of these are slow as compared to orbital electrons, but the energy transferred to such slow particles is generally relatively small. Yet, it contributes significantly to the dose absorbed from 0.1-30 keV neutrons. In tissue all recoils induced by neutrons of less than 30 keV are slow, and above 0.1 keV the absorbed dose due to collisiondominates over that due to capture reactions. The aim of the present paper is to identify those intervals of neutron energy in which atomic collision damage is most probable in living matter. The results of calculations presented here indicate that atomic collisions should be most significant for 0.5-3 keV neutrons. (author)

  8. Raman, Infrared, and Laser-Induced Breakdown Spectroscopy Identification of Particles in Raw Materials.

    Science.gov (United States)

    Lee, Kathryn; Lankers, Markus; Valet, Oliver

    2018-02-01

    Raw materials need to be of a certain quality with respect to physical and chemical composition. They also need to have no contaminants, including particles, because these could indicate raw material impurities or contaminate the product. Particle identification allows determination of process conditions that caused them and whether the quality of the final product is acceptable. Particles may appear to the eye to be very different things than they actually are. They may be coated with the raw material and may consist of several components; therefore, chemical and elemental analyses are required for accuracy in proper identification and definitive information about their source. Thus, microscope versions of Raman spectroscopy, laser-induced breakdown spectroscopy (LIBS), and infrared (IR) spectroscopy are excellent tools for identifying particles in materials. Those tools are fast and accurate, and can provide chemical and elemental composition as well as images that can aid identification. The micro-analysis capabilities allow for easy analysis of different portions of samples so that multiple components can be identified and sample preparation can be reduced or eliminated. The differences in sensitivities of Raman and IR spectroscopies to different functional groups as well as the elemental analysis provided by LIBS and the image analysis provided by the microscopy makes these complementary techniques and provides the advantage of identifying various chemical components. Proper spectral searching techniques and interpretation of the results are important for interpretation and identification of trace contaminants.

  9. The measurement and modeling of alpha-particle-induced charge collection in dynamic memories

    International Nuclear Information System (INIS)

    Oldiges, P.J.

    1989-01-01

    This thesis addresses the problem of α-particle-induced charge collection in high-density dynamic random access memories. A novel technique for the measurement of charge collection in high-density memory cells and bit lines due to α-particle strikes was developed. The technique involves D.C. tests on simple test structures with an α-particle source on the device package as a lid. The advantages of this new measurement technique are: the method allows for in-situ measurements of charge collection on both MOS capacitors and bit lines found in present-day memories; the on-chip measurement technique minimizes errors due to external probes loading the device under test; the measurements can be controlled by a personal computer, with the data being able to be reduced on the same machine. Results obtained using this new measurement technique show that the charge collection is found to depend upon test-structure size and the configuration of its neighbors. Results of two-dimensional simulations of charge flow along the surface of an MOS capacitor from current injection due to an α-particle strike indicate that a spatial potential variation of 0.5V may occur between the point of current injection and capacitor edge for a 1M dRAM capacitor

  10. Confined active Brownian particles: theoretical description of propulsion-induced accumulation

    Science.gov (United States)

    Das, Shibananda; Gompper, Gerhard; Winkler, Roland G.

    2018-01-01

    The stationary-state distribution function of confined active Brownian particles (ABPs) is analyzed by computer simulations and analytical calculations. We consider a radial harmonic as well as an anharmonic confinement potential. In the simulations, the ABP is propelled with a prescribed velocity along a body-fixed direction, which is changing in a diffusive manner. For the analytical approach, the Cartesian components of the propulsion velocity are assumed to change independently; active Ornstein-Uhlenbeck particle (AOUP). This results in very different velocity distribution functions. The analytical solution of the Fokker-Planck equation for an AOUP in a harmonic potential is presented and a conditional distribution function is provided for the radial particle distribution at a given magnitude of the propulsion velocity. This conditional probability distribution facilitates the description of the coupling of the spatial coordinate and propulsion, which yields activity-induced accumulation of particles. For the anharmonic potential, a probability distribution function is derived within the unified colored noise approximation. The comparison of the simulation results with theoretical predictions yields good agreement for large rotational diffusion coefficients, e.g. due to tumbling, even for large propulsion velocities (Péclet numbers). However, we find significant deviations already for moderate Péclet number, when the rotational diffusion coefficient is on the order of the thermal one.

  11. Structure evolution of gelatin particles induced by pH and ionic strength.

    Science.gov (United States)

    Xu, Jing; Li, Tianduo; Tao, Furong; Cui, Yuezhi; Xia, Yongmei

    2013-03-01

    Microstructure of gelatin particles played a key role in determining the physicochemical properties of gelatin. Ionic strength and pH as systematic manners were considered to affect gelatin particles structure on the micrometer scale. Scanning electron microscopy was used for depicting the morphologies of gelatin particles. Increasing pH to 10.0 or decreasing pH to 4.0, spherical, spindle, and irregular aggregates of gelatin particles at 2, 6, 10, and 14% solution (w/w) were all transformed to spindle aggregates. When NaCl was added to the system, the molecular chains of gelatin possibly rearranged themselves in a stretched state, and the ribbon aggregates was observed. The structural transitions of gelatin aggregates were strongly depended on the electrostatic repulsion. In the gelatin-sodium dodecyl sulfate (SDS) case, the micrometer scale of aggregates was larger and the different degrees of cross-links were induced through hydrophobic interaction and electrostatic repulsion. Copyright © 2012 Wiley Periodicals, Inc.

  12. Investigation into process-induced de-aggregation of cohesive micronised API particles.

    Science.gov (United States)

    Hoffmann, Magnus; Wray, Patrick S; Gamble, John F; Tobyn, Mike

    2015-09-30

    The aim of this study was to assess the impact of unit processes on the de-aggregation of a cohesive micronised API within a pharmaceutical formulation using near-infrared chemical imaging. The impact on the primary API particles was also investigated using an image-based particle characterization system with integrated Raman analysis. The blended material was shown to contain large, API rich domains which were distributed in-homogeneously across the sample, suggesting that the blending process was not aggressive enough to disperse aggregates of micronised drug particles. Cone milling, routinely used to improve the homogeneity of such cohesive formulations, was observed to substantially reduce the number and size of API rich domains; however, several smaller API domains survived the milling process. Conveyance of the cone milled formulation through the Alexanderwerk WP120 powder feed system completely dispersed all remaining aggregates. Importantly, powder feed transmission of the un-milled formulation was observed to produce an equally homogeneous API distribution. The size of the micronised primary drug particles remained unchanged during powder feed transmission. These findings provide further evidence that this powder feed system does induce shear, and is in fact better able to disperse aggregates of a cohesive micronised API within a blend than the blend-mill-blend step. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  13. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)], E-mail: ljw@ipp.ac.cn

    2007-11-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of {gamma}-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process (<1 h post irradiation), and the generation of micronuclei (MN), a sensitive marker for relative long process of RIBE. Our results showed that in the absence of irradiation, NaCl at elevated concentration such as 8.0, 9.0 and 10.0 g/L did not significantly increase the frequency of {gamma}-H2AX foci-positive cells and the number of foci per positive cell comparing with that NaCl at a normal concentration (6.8 g/L). However, with 0.2 cGy {alpha}-particle irradiation, the induced fraction of {gamma}-H2AX foci-positive cells and the number of induced {gamma}-H2AX foci per positive cell were significantly increased in both irradiated and adjacent non-irradiated regions. Similarly, the induction of MN by 0.2 cGy {alpha}-particle irradiation also increased with the elevated NaCl concentrations. With N{sup G}-methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy {alpha}-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose {alpha}-particle irradiation and nitric oxide generated by irradiation was also very important in this process.

  14. Ultrafine titanium dioxide particles in the absence of photoactivation can induce oxidative damage to human bronchial epithelial cells

    International Nuclear Information System (INIS)

    Gurr, J.-R.; Wang, Alexander S.S.; Chen, C.-H.; Jan, K.-Y.

    2005-01-01

    Ultrafine titanium dioxide (TiO 2 ) particles have been shown to exhibit strong cytotoxicity when exposed to UVA radiation, but are regarded as a biocompatible material in the absence of photoactivation. In contrast to this concept, the present results indicate that anatase-sized (10 and 20 nm) TiO 2 particles in the absence of photoactivation induced oxidative DNA damage, lipid peroxidation, and micronuclei formation, and increased hydrogen peroxide and nitric oxide production in BEAS-2B cells, a human bronchial epithelial cell line. However, the treatment with anatase-sized (200 and >200 nm) particles did not induce oxidative stress in the absence of light irradiation; it seems that the smaller the particle, the easier it is for the particle to induce oxidative damage. The photocatalytic activity of the anatase form of TiO 2 was reported to be higher than that of the rutile form. In contrast to this notion, the present results indicate that rutile-sized 200 nm particles induced hydrogen peroxide and oxidative DNA damage in the absence of light but the anatase-sized 200 nm particles did not. In total darkness, a slightly higher level of oxidative DNA damage was also detected with treatment using an anatase-rutile mixture than with treatment using either the anatase or rutile forms alone. These results suggest that intratracheal instillation of ultrafine TiO 2 particles may cause an inflammatory response

  15. Adenovirus Particles that Display the Plasmodium falciparum Circumsporozoite Protein NANP Repeat Induce Sporozoite-Neutralizing Antibodies in Mice

    OpenAIRE

    Palma, Christopher; Overstreet, Michael G.; Guedon, Jean-Marc; Hoiczyk, Egbert; Ward, Cameron; Karen, Kasey A.; Zavala, Fidel; Ketner, Gary

    2011-01-01

    Adenovirus particles can be engineered to display exogenous peptides on their surfaces by modification of viral capsid proteins, and particles that display pathogen-derived peptides can induce protective immunity. We constructed viable recombinant adenoviruses that display B-cell epitopes from the Plasmodium falciparum circumsporozoite protein (PfCSP) in the major adenovirus capsid protein, hexon. Recombinants induced high-titer antibodies against CSP when injected intraperitoneally into mice...

  16. Production of medically useful bromine isotopes via alpha-particle induced nuclear reactions

    Science.gov (United States)

    Breunig, Katharina; Scholten, Bernhard; Spahn, Ingo; Hermanne, Alex; Spellerberg, Stefan; Coenen, Heinz H.; Neumaier, Bernd

    2017-09-01

    The cross sections of α-particle induced reactions on arsenic leading to the formation of 76,77,78Br were measured from their respective thresholds up to 37 MeV. Thin sediments of elemental arsenic powder were irradiated together with Al degrader and Cu monitor foils using the established stacked-foil technique. For determination of the effective α-particle energies and of the effective beam current through the stacks the cross-section ratios of the monitor nuclides 67Ga/66Ga were used. This should help resolve discrepancies in existing literature data. Comparison of the data with the available excitation functions shows some slight energy shifts as well as some differences in curve shapes. The calculated thick target yields indicate, that 77Br can be produced in the energy range Eα = 25 → 17 MeV free of isotopic impurities in quantities sufficient for medical application.

  17. Induced wettability and surface-volume correlation of composition for bovine bone derived hydroxyapatite particles

    Science.gov (United States)

    Maidaniuc, Andreea; Miculescu, Florin; Voicu, Stefan Ioan; Andronescu, Corina; Miculescu, Marian; Matei, Ecaterina; Mocanu, Aura Catalina; Pencea, Ion; Csaki, Ioana; Machedon-Pisu, Teodor; Ciocan, Lucian Toma

    2018-04-01

    Hydroxyapatite powders characteristics need to be determined both for quality control purposes and for a proper control of microstructural features of bone reconstruction products. This study combines bulk morphological and compositional analysis methods (XRF, SEM-EDS, FT-IR) with surface-related methods (XPS, contact angle measurements) in order to correlate the characteristics of hydroxyapatite powders derived from bovine bone for its use in medical applications. An experimental approach for correlating the surface and volume composition was designed based on the analysis depth of each spectral method involved in the study. Next, the influences of powder particle size and forming method on the contact angle between water drops and ceramic surface were evaluated for identifying suitable strategies of tuning hydroxyapatite's wettability. The results revealed a preferential arrangement of chemical elements at the surface of hydroxyapatite particles which could induce a favourable material behaviour in terms of sinterability and biological performance.

  18. Production of medically useful bromine isotopes via alpha-particle induced nuclear reactions

    Directory of Open Access Journals (Sweden)

    Breunig Katharina

    2017-01-01

    Full Text Available The cross sections of α-particle induced reactions on arsenic leading to the formation of 76,77,78Br were measured from their respective thresholds up to 37 MeV. Thin sediments of elemental arsenic powder were irradiated together with Al degrader and Cu monitor foils using the established stacked-foil technique. For determination of the effective α-particle energies and of the effective beam current through the stacks the cross-section ratios of the monitor nuclides 67Ga/66Ga were used. This should help resolve discrepancies in existing literature data. Comparison of the data with the available excitation functions shows some slight energy shifts as well as some differences in curve shapes. The calculated thick target yields indicate, that 77Br can be produced in the energy range Eα = 25 → 17 MeV free of isotopic impurities in quantities sufficient for medical application.

  19. Plume expansion of a laser-induced plasma studied with the particle-in-cell method

    DEFF Research Database (Denmark)

    Ellegaard, O.; Nedelea, T.; Schou, Jørgen

    2002-01-01

    energy as well as electron energy. We have estimated the time constant for energy transfer between the electrons and the ions. The scaling of these processes is given by a single parameter determined by the Debye length obtained from the electron density in the plasma outside the surface. (C) 2002......The initial stage of laser-induced plasma plume expansion from a solid in vacuum and the effect of the Coulomb field have been studied. We have performed a one-dimensional numerical calculation by mapping the charge on a computational grid according to the particle-in-cell (PIC) method of Birdsall...... et al. It is assumed that the particle ablation from a surface with a fixed temperature takes place as a pulse, i.e. within a finite period of time. A number of characteristic quantities for the plasma plume are compared with similar data for expansion of neutrals as well as fluid models: Density...

  20. Investigation of DNA double strand breaks induced by α particle and 7Li ions

    International Nuclear Information System (INIS)

    Kong Fuquan; Cai Minghui; Zhao Kui; Guo Jiyu; Ni Meinan; Sui Li; Yang Mingjian; Zhan Yong

    2006-01-01

    α particles and Lithium ions were produced by 241 Am radiation source and HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE) respectively to simulate ionizing radiation in Boron Neutron Capture Therapy (BNCT) process. Plasmid DNA in aqueous solution was irradiated and the DNA fragments were imaged by AFM. The image software ImageJ was used to measure the length of DNA fragments. The length distribution and conformation changes of DNA fragments were assessed. Our results showed that the mean length of DNA fragments as well as the fraction of linear and open circle DNA molecules decreased by dose. At higher dose, Lithium ions induced more pronounced relative biological effects than α particles. (author)

  1. Alpha particle induced DNA damage and repair in normal cultured thyrocytes of different proliferation status

    DEFF Research Database (Denmark)

    Lyckesvärd, Madeleine Nordén; Delle, Ulla; Kahu, Helena

    2014-01-01

    Childhood exposure to ionizing radiation increases the risk of developing thyroid cancer later in life and this is suggested to be due to higher proliferation of the young thyroid. The interest of using high-LET alpha particles from Astatine-211 ((211)At), concentrated in the thyroid by the same...... mechanism as (131)I [1], in cancer treatment has increased during recent years because of its high efficiency in inducing biological damage and beneficial dose distribution when compared to low-LET radiation. Most knowledge of the DNA damage response in thyroid is from studies using low-LET irradiation...... and much less is known of high-LET irradiation. In this paper we investigated the DNA damage response and biological consequences to photons from Cobolt-60 ((60)Co) and alpha particles from (211)At in normal primary thyrocytes of different cell cycle status. For both radiation qualities the intensity...

  2. Neutron-induced particle production in the cumulative and noncumulative regions at intermediate energies

    International Nuclear Information System (INIS)

    Mashnik, S.G.

    1992-01-01

    The first systematic measurements of neutron-induced inclusive production of protons, deuterons, tritons and charged pions on carbon, copper, and bismuth in the bombarding energy range of 300-580 MeV and in the angular interval from 51 deg to 165 deg have been analyzed in the framework of the cascade-exciton model. The role of single-particle scattering, the effects of rescattering, the pre-equilibrium emission and 'coalescence' mechanism in particle production in the cumulative (i.e., kinematically - forbidden for quasi-free intranuclear projectile-nucleon collisions) and noncumulative regions are discussed. A week sensitivity of the inclusive distributions to the specific reaction mechanisms and a need of correlation and polarization measurements are noted. 27 refs.; 12 figs.; 1 tab

  3. Elevated sodium chloride concentrations enhance the bystander effects induced by low dose alpha-particle irradiation

    International Nuclear Information System (INIS)

    Han Wei; Zhu Lingyan; Jiang Erkang; Wang Jun; Chen Shaopeng; Bao Linzhi; Zhao Ye; Xu An; Yu Zengliang; Wu Lijun

    2007-01-01

    Previous studies have shown that high NaCl can be genotoxic, either alone or combined with irradiation. However, little is known about the relationship between environmental NaCl at elevated conditions and radiation-induced bystander effects (RIBE). RIBE, which has been considered as non-targeted bystander responses, has been demonstrated to occur widely in various cell lines. In the present study, RIBE under the elevated NaCl culture condition was assessed in AG 1522 cells by both the induction of γ-H2AX, a reliable marker of DNA double-strand break (DSB) for the early process ( G -methyl-L-arginine, an inhibitor of nitric oxide synthase, the induced fraction of foci-positive cells was effectively inhibited both in 0.2 cGy α-particle irradiated and adjacent non-irradiated regions under either normal or elevated NaCl conditions. These results suggested that the cultures with elevated NaCl medium magnified the damage effects induced by the low dose α-particle irradiation and nitric oxide generated by irradiation was also very important in this process

  4. Ultrafine particles from diesel engines induce vascular oxidative stress via JNK activation.

    Science.gov (United States)

    Li, Rongsong; Ning, Zhi; Cui, Jeffery; Khalsa, Bhavraj; Ai, Lisong; Takabe, Wakako; Beebe, Tyler; Majumdar, Rohit; Sioutas, Constantinos; Hsiai, Tzung

    2009-03-15

    Exposure to particulate air pollution is linked to increased incidences of cardiovascular diseases. Ambient ultrafine particles (UFP) from diesel vehicle engines have been shown to be proatherogenic in ApoE knockout mice and may constitute a major cardiovascular risk in humans. We posited that circulating nano-sized particles from traffic pollution sources induce vascular oxidative stress via JNK activation in endothelial cells. Diesel UFP were collected from a 1998 Kenworth truck. Intracellular superoxide assay revealed that these UFP dose-dependently induced superoxide (O(2)(-)) production in human aortic endothelial cells (HAEC). Flow cytometry showed that UFP increased MitoSOX red intensity specific for mitochondrial superoxide. Protein carbonyl content was increased by UFP as an indication of vascular oxidative stress. UFP also up-regulated heme oxygenase-1 (HO-1) and tissue factor (TF) mRNA expression, and pretreatment with the antioxidant N-acetylcysteine significantly decreased their expression. Furthermore, UFP transiently activated JNK in HAEC. Treatment with the JNK inhibitor SP600125 and silencing of both JNK1 and JNK2 with siRNA inhibited UFP-stimulated O(2)(-) production and mRNA expression of HO-1 and TF. Our findings suggest that JNK activation plays an important role in UFP-induced oxidative stress and stress response gene expression.

  5. Analysis of irradiation-induced stresses in coating layers of coated fuel particles for the High Temperature Engineering Test Reactor (HTTR)

    International Nuclear Information System (INIS)

    Hayashi, Kimio; Kikuchi, Teruo; Fukuda, Kousaku; Sato, Sadao; Toyota, Junji; Shiozawa, Shusaku; Sawa, Kazuhiro; Kashimura, Satoru.

    1991-07-01

    Irradiation-induced stresses in coating layers of coated fuel particles were analyzed by the MICROS-2 code for the fuels of the High Temperature Engineering Test Reactor (HTTR) under its operating conditions. The analyses were made on the standard core fuel (A-type) and the test fuels comprising the advanced SiC-coated particle fuel (B-1 type) and the ZrC-coated particle fuel (B-2 type). For the B-1 type fuel, the stresses were relieved due to the thicker buffer and SiC layers than for the A type fuel. The slightly decreased thickness of the fourth layer for the B-1 type than for the A type fuel had no significant effect on the stresses. As for the B-2 type fuel, almost the same results as for the B-1 type were obtained under an assumption that the ZrC layer as well as the SiC layer undergoes negligible dimension change within the analysis conditions. The obtained results indicated that the B-1 and B-2 type fuels are better than the A type fuel in terms of integrity against the irradiation-induced stresses. Finally, research subjects for development of the analysis code on the fuel behavior are discussed. (author)

  6. Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes

    KAUST Repository

    Li, Yiyang; El Gabaly, Farid; Ferguson, Todd R.; Smith, Raymond B.; Bartelt, Norman C.; Sugar, Joshua D.; Fenton, Kyle R.; Cogswell, Daniel A.; Kilcoyne, A. L. David; Tyliszczak, Tolek; Bazant, Martin Z.; Chueh, William C.

    2014-01-01

    ©2014 Macmillan Publishers Limited. All rights reserved. Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO 4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

  7. Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes.

    Science.gov (United States)

    Li, Yiyang; El Gabaly, Farid; Ferguson, Todd R; Smith, Raymond B; Bartelt, Norman C; Sugar, Joshua D; Fenton, Kyle R; Cogswell, Daniel A; Kilcoyne, A L David; Tyliszczak, Tolek; Bazant, Martin Z; Chueh, William C

    2014-12-01

    Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

  8. Current-induced transition from particle-by-particle to concurrent intercalation in phase-separating battery electrodes

    KAUST Repository

    Li, Yiyang

    2014-09-14

    ©2014 Macmillan Publishers Limited. All rights reserved. Many battery electrodes contain ensembles of nanoparticles that phase-separate on (de)intercalation. In such electrodes, the fraction of actively intercalating particles directly impacts cycle life: a vanishing population concentrates the current in a small number of particles, leading to current hotspots. Reports of the active particle population in the phase-separating electrode lithium iron phosphate (LiFePO 4; LFP) vary widely, ranging from near 0% (particle-by-particle) to 100% (concurrent intercalation). Using synchrotron-based X-ray microscopy, we probed the individual state-of-charge for over 3,000 LFP particles. We observed that the active population depends strongly on the cycling current, exhibiting particle-by-particle-like behaviour at low rates and increasingly concurrent behaviour at high rates, consistent with our phase-field porous electrode simulations. Contrary to intuition, the current density, or current per active internal surface area, is nearly invariant with the global electrode cycling rate. Rather, the electrode accommodates higher current by increasing the active particle population. This behaviour results from thermodynamic transformation barriers in LFP, and such a phenomenon probably extends to other phase-separating battery materials. We propose that modifying the transformation barrier and exchange current density can increase the active population and thus the current homogeneity. This could introduce new paradigms to enhance the cycle life of phase-separating battery electrodes.

  9. Visualisation of γH2AX Foci Caused by Heavy Ion Particle Traversal; Distinction between Core Track versus Non-Track Damage

    Science.gov (United States)

    Nakajima, Nakako Izumi; Brunton, Holly; Watanabe, Ritsuko; Shrikhande, Amruta; Hirayama, Ryoichi; Matsufuji, Naruhiro; Fujimori, Akira; Murakami, Takeshi; Okayasu, Ryuichi; Jeggo, Penny; Shibata, Atsushi

    2013-01-01

    Heavy particle irradiation produces complex DNA double strand breaks (DSBs) which can arise from primary ionisation events within the particle trajectory. Additionally, secondary electrons, termed delta-electrons, which have a range of distributions can create low linear energy transfer (LET) damage within but also distant from the track. DNA damage by delta-electrons distant from the track has not previously been carefully characterised. Using imaging with deconvolution, we show that at 8 hours after exposure to Fe (∼200 keV/µm) ions, γH2AX foci forming at DSBs within the particle track are large and encompass multiple smaller and closely localised foci, which we designate as clustered γH2AX foci. These foci are repaired with slow kinetics by DNA non-homologous end-joining (NHEJ) in G1 phase with the magnitude of complexity diminishing with time. These clustered foci (containing 10 or more individual foci) represent a signature of DSBs caused by high LET heavy particle radiation. We also identified simple γH2AX foci distant from the track, which resemble those arising after X-ray exposure, which we attribute to low LET delta-electron induced DSBs. They are rapidly repaired by NHEJ. Clustered γH2AX foci induced by heavy particle radiation cause prolonged checkpoint arrest compared to simple γH2AX foci following X-irradiation. However, mitotic entry was observed when ∼10 clustered foci remain. Thus, cells can progress into mitosis with multiple clusters of DSBs following the traversal of a heavy particle. PMID:23967070

  10. Effect of particle size on hydroxyapatite crystal-induced tumor necrosis factor alpha secretion by macrophages.

    Science.gov (United States)

    Nadra, Imad; Boccaccini, Aldo R; Philippidis, Pandelis; Whelan, Linda C; McCarthy, Geraldine M; Haskard, Dorian O; Landis, R Clive

    2008-01-01

    Macrophages may promote a vicious cycle of inflammation and calcification in the vessel wall by ingesting neointimal calcific deposits (predominantly hydroxyapatite) and secreting tumor necrosis factor (TNF)alpha, itself a vascular calcifying agent. Here we have investigated whether particle size affects the proinflammatory potential of hydroxyapatite crystals in vitro and whether the nuclear factor (NF)-kappaB pathway plays a role in the macrophage TNFalpha response. The particle size and nano-topography of nine different crystal preparations was analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and gas sorbtion analysis. Macrophage TNFalpha secretion was inversely related to hydroxyapatite particle size (P=0.011, Spearman rank correlation test) and surface pore size (P=0.014). A necessary role for the NF-kappaB pathway was demonstrated by time-dependent I kappaB alpha degradation and sensitivity to inhibitors of I kappaB alpha degradation. To test whether smaller particles were intrinsically more bioactive, their mitogenic activity on fibroblast proliferation was examined. This showed close correlation between TNFalpha secretion and crystal-induced fibroblast proliferation (P=0.007). In conclusion, the ability of hydroxyapatite crystals to stimulate macrophage TNFalpha secretion depends on NF-kappaB activation and is inversely related to particle and pore size, with crystals of 1-2 microm diameter and pore size of 10-50 A the most bioactive. Microscopic calcific deposits in early stages of atherosclerosis may therefore pose a greater inflammatory risk to the plaque than macroscopically or radiologically visible deposits in more advanced lesions.

  11. Venezuelan Equine Encephalitis Replicon Particles Can Induce Rapid Protection against Foot-and-Mouth Disease Virus

    OpenAIRE

    Diaz-San Segundo, Fayna; Dias, Camila C. A.; Moraes, Mauro P.; Weiss, Marcelo; Perez-Martin, Eva; Owens, Gary; Custer, Max; Kamrud, Kurt; de los Santos, Teresa; Grubman, Marvin J.

    2013-01-01

    We have previously shown that delivery of the porcine type I interferon gene (poIFN-α/β) with a replication-defective human adenovirus vector (adenovirus 5 [Ad5]) can sterilely protect swine challenged with foot-and-mouth disease virus (FMDV) 1 day later. However, the need of relatively high doses of Ad5 limits the applicability of such a control strategy in the livestock industry. Venezuelan equine encephalitis virus (VEE) empty replicon particles (VRPs) can induce rapid protection of mice a...

  12. Fluorine determination in human and animal bones by particle-induced gamma-ray emission

    International Nuclear Information System (INIS)

    Sastri, Chaturvedula S.; Hoffmann, Peter; Ortner, Hugo M.; Iyengar, Venkatesh; Blondiaux, Gilbert; Tessier, Yves; Petri, Hermann; Aras, Namik K.; Zaichick, Vladimir

    2002-01-01

    Fluorine was determined in the iliac crest bones of patients and in ribs collected from postmortem investigations by particle-induced gamma-ray emission based on the 19 F(p,pγ) 19 F reaction, using 20/2.5 MeV protons. The results indicate that for 68% of the human samples the F concentration is in the range 500-1999 μg g -1 . For comparison purposes fluorine was also determined in some animal bones; in some animal tissues lateral profiles of fluorine were measured. (abstract)

  13. Development of a Reference Database for Particle Induced Gamma Ray Emission (PIGE) Spectroscopy

    International Nuclear Information System (INIS)

    2017-09-01

    Ion beam analysis techniques are non-destructive analytical techniques used to identify the composition and structure of surface layers of materials. The applications of these techniques span environmental control, cultural heritage and conservation, materials and fusion technologies. The particle-induced gamma-ray emission (PIGE) spectroscopy technique in particular, is a powerful tool for detecting light elements in certain depths of surface layers. This publication describes the coordinated effort to measure and compile cross section data relevant to PIGE analysis and make these data available to the community of practice through a comprehensive online database.

  14. Pre-equilibrium decay process in alpha particle induced reactions on thulium and tantalum

    International Nuclear Information System (INIS)

    Mohan, Rao, A.V.; Chintalapudi, S.N.

    1994-01-01

    Alpha particle induced reactions on the target elements Thulium and Tantalum were investigated upto 60 MeV using stacked foil activation technique and Ge(Li) gamma ray spectroscopy method. Excitation functions for six reactions of 169 Tm(α,xn); x=1-4 and 181 Ta(α,xn); x=2,4 were studied. The experimental results were compared with the updated version of Hybrid model (ALICE/90) using initial exciton configuration n 0 =4(4pOh). A general agreement was found for all the reactions with this option. (author)

  15. Pre-equilibrium decay process in alpha particle induced reactions on thulium and tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Rao, A.V.; Chintalapudi, S.N. (Inter Univ. Consortium for Dept. of atomic Energy Facilities, Calcutta (India))

    1994-01-01

    Alpha particle induced reactions on the target elements Thulium and Tantalum were investigated upto 60 MeV using stacked foil activation technique and Ge(Li) gamma ray spectroscopy method. Excitation functions for six reactions of [sup 169]Tm([alpha],xn); x=1-4 and [sup 181]Ta([alpha],xn); x=2,4 were studied. The experimental results were compared with the updated version of Hybrid model (ALICE/90) using initial exciton configuration n[sub 0]=4(4pOh). A general agreement was found for all the reactions with this option. (author).

  16. Influence of catechins on bystander responses in CHO cells induced by alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Law, Y.L.; Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)], E-mail: peter.yu@cityu.edu.hk

    2010-04-15

    In this work, we studied alpha-particle induced and medium-mediated bystander effects in Chinese hamster ovary (CHO) cells through micronucleus (MN) assay. We showed that signal transduction from irradiated cells to bystander cells occur within a short time after irradiation. We then studied the effects of ROS (reactive oxygen species)-scavenging catechins in the medium before irradiation. We observed decreases in the percentage of bystander cells with MN formation and thus proved the protection effect of catechins on bystander cells from radiation.

  17. Particle induced X-ray emission: a valuable tool for the analysis of metalpoint drawings

    International Nuclear Information System (INIS)

    Duval, A.; Guicharnaud, H.; Dran, J.C.

    2004-01-01

    For several years, we carry out a research on metalpoint drawings, a graphic technique mainly employed by European artists during the 15th and 16th centuries. As a non-destructive and very sensitive analytical technique is required, particle induced X-ray emission (PIXE) analysis with an external beam has been used for this purpose. More than 70 artworks drawn by Italian, Flemish and German artists have been analysed, including leadpoint and silverpoint drawings. Following a short description of the metalpoint technique, the results are compared with the recipes written by Cennino Cennini at the beginning of the 15th century and specific examples are presented

  18. Occurrence of dead core in catalytic particles containing immobilized enzymes: analysis for the Michaelis-Menten kinetics and assessment of numerical methods.

    Science.gov (United States)

    Pereira, Félix Monteiro; Oliveira, Samuel Conceição

    2016-11-01

    In this article, the occurrence of dead core in catalytic particles containing immobilized enzymes is analyzed for the Michaelis-Menten kinetics. An assessment of numerical methods is performed to solve the boundary value problem generated by the mathematical modeling of diffusion and reaction processes under steady state and isothermal conditions. Two classes of numerical methods were employed: shooting and collocation. The shooting method used the ode function from Scilab software. The collocation methods included: that implemented by the bvode function of Scilab, the orthogonal collocation, and the orthogonal collocation on finite elements. The methods were validated for simplified forms of the Michaelis-Menten equation (zero-order and first-order kinetics), for which analytical solutions are available. Among the methods covered in this article, the orthogonal collocation on finite elements proved to be the most robust and efficient method to solve the boundary value problem concerning Michaelis-Menten kinetics. For this enzyme kinetics, it was found that the dead core can occur when verified certain conditions of diffusion-reaction within the catalytic particle. The application of the concepts and methods presented in this study will allow for a more generalized analysis and more accurate designs of heterogeneous enzymatic reactors.

  19. Expression, purification, crystallization and preliminary X-ray crystallographic studies of hepatitis B virus core fusion protein corresponding to octahedral particles

    International Nuclear Information System (INIS)

    Kikuchi, Masaki; Iwabuchi, Shinichiro; Kikkou, Tatsuhiko; Noguchi, Keiichi; Odaka, Masafumi; Yohda, Masafumi; Kawata, Masaaki; Sato, Chikara; Matsumoto, Osamu

    2013-01-01

    Novel hepatitis B virus-like particles of recombinant dimeric core–GFP fusion protein were expressed, purified and crystallized. The crystals diffracted to 2.15 Å resolution and belonged to space group F432, with unit-cell parameters a = b = c = 219.7 Å. Recombinant hepatitis B virus core proteins dimerize to form building blocks that are capable of self-assembly into a capsid. A core capsid protein dimer (CPD) linked to a green fluorescent protein variant, EGFP, at the C-terminus has been designed. The recombinant fusion CPD was expressed in Escherichia coli, assembled into virus-like particles (VLPs), purified and crystallized. The single crystal diffracted to 2.15 Å resolution and belonged to the cubic space group F432, with unit-cell parameters a = b = c = 219.7 Å. The fusion proteins assembled into icosahedral VLPs in aqueous solution, but were rearranged into octahedral symmetry through the crystal-packing process under the crystallization conditions

  20. Long-term changes in amphetamine-induced reinforcement and aversion in rats following exposure to 56Fe particle

    Science.gov (United States)

    Rabin, B. M.; Joseph, J. A.; Shukitt-Hale, B.

    Exposing rats to heavy particles produces alterations in the functioning of dopaminergic neurons and in the behaviors that depend upon the integrity of the dopaminergic system. Two of these dopamine-dependent behaviors include amphetamine-induced reinforcement, measure using the conditioned place preference procedure, and amphetamine-induced reinforcement, measured using the conditioned place preference procedure, and amphetamine-induced aversion, measured using the conditioned taste aversion. Previous research has shown that exposing rats to 1.0 Gy of 1GeV/n 56Fe particles produced a disruption of an amphetamine-induced taste aversion 3 days following exposure, but produced an apparent enhancement of the aversion 112 days following exposure. The present experiments were designed to provide a further evaluation of these results by examining taste aversion learning 154 days following exposure to 1.0Gy 56Fe particles and to establish the convergent validity of the taste aversion results by looking at the effects of exposure on the establishment of an amphetamine-induced conditioned place preference 3, 7, and 16 weeks following irradiation. The taste aversion results failed to confirm the apparent enhancement of the amphetamine-induced CTA observed in the prior experiment. However, exposure to 56Fe particles prevented the acquisition of amphetamine-induced place preference at all three-time intervals. The results are interpreted as indicating that exposure to heavy particles can produce long-term changes in behavioral functioning.

  1. Turbulence-induced heat transfer in PBMR core using LES and RANS

    International Nuclear Information System (INIS)

    Lee, Jung-Jae; Yoon, Su-Jong; Park, Goon-Cherl; Lee, Won-Jae

    2007-01-01

    This paper introduces the results of numerical simulations on flow fields and relevant heat transfer in the pebble bed reactor (PBR) core, since the coolant passes a highly complicated random flow path with a high Reynolds number, an appropriate treatment of the turbulence is required. A set of simple experiments for the flow over a circular cylinder with heat transfer was conducted to finally select the large eddy simulation (LES) and k-ω model among the considering Reynolds-averaged Navier-Stokes (RANS) models for PBR application. Using these models, the PBR cores, whose geometries were simplified to the body-centered cubical (BCC) and face-centered cubical (FCC) structures, were simulated. A larger pressure drop, a more random flow field, a higher vorticity magnitude and a higher temperature at the local hot spots on the pebble surface were found in the results of the LES than in those of RANS for both geometries. In cases of the LES, the flow structures were resolved up to the grid scales. Irregular distributions of the flow and local heat transfer were found in the BCC core, while relatively regular distributions for the FCC core. The turbulent nature of the coolant flow in the pebble core evidently affected the fuel surface temperature distribution. (author)

  2. Investigation of electrically-active deep levels in single-crystalline diamond by particle-induced charge transient spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kada, W., E-mail: kada.wataru@gunma-u.ac.jp [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kambayashi, Y.; Ando, Y. [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Onoda, S. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Umezawa, H.; Mokuno, Y. [National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Shikata, S. [Kwansei Gakuin Univ., 2-1, Gakuen, Mita, Hyogo 669-1337 (Japan); Makino, T.; Koka, M. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Hanaizumi, O. [Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515 (Japan); Kamiya, T.; Ohshima, T. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan)

    2016-04-01

    To investigate electrically-active deep levels in high-resistivity single-crystalline diamond, particle-induced charge transient spectroscopy (QTS) techniques were performed using 5.5 MeV alpha particles and 9 MeV carbon focused microprobes. For unintentionally-doped (UID) chemical vapor deposition (CVD) diamond, deep levels with activation energies of 0.35 eV and 0.43 eV were detected which correspond to the activation energy of boron acceptors in diamond. The results suggested that alpha particle and heavy ion induced QTS techniques are the promising candidate for in-situ investigation of deep levels in high-resistivity semiconductors.

  3. Particle induced x-ray emission (PIXE) measurement of the Cd content in animal tissues

    International Nuclear Information System (INIS)

    Le Huong Quynh; Demeter, I.; Hollos-Nagy, K.; Szoekefalvi-Nagy, Z.

    1989-12-01

    Particle induced x-ray emission (PIXE) measurements were performed on thin samples prepared from different rabbit tissues, using 3 MeV proton beam for inducing x-rays from the animal tissues. This method is very sensitive and very small amounts of trace elements can be detected. Cadmium, one of the most toxic elements which can be concentrated in animal and human tissues due to environmental pollution, was detected with a limit of 0.7 ppm. The trace element concentrations obtained by PIXE were compared to those measured by atomic absorption spectrometry. PIXE method is proposed for routine analysis at the Veterinary and Food Investigating Service, Budapest, Hungary. (D.Gy.) 6 refs.; 3 figs

  4. Changes in the surface electronic states of semiconductor fine particles induced by high energy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yamaki, Tetsuya; Asai, Keisuke; Ishigure, Kenkichi [Tokyo Univ. (Japan); Shibata, Hiromi

    1997-03-01

    The changes in the surface electronic states of Q-sized semiconductor particles in Langmuir-Blodgett (LB) films, induced by high energy ion irradiation, were examined by observation of ion induced emission and photoluminescence (PL). Various emission bands attributed to different defect sites in the band gap were observed at the initial irradiation stage. As the dose increased, the emissions via the trapping sites decreased in intensity while the band-edge emission developed. This suggests that the ion irradiation would remove almost all the trapping sites in the band gap. The low energy emissions, which show a multiexponential decay, were due to a donor-acceptor recombination between the deeply trapped carriers. It was found that the processes of formation, reaction, and stabilization of the trapping sites would predominantly occur under the photooxidizing conditions. (author)

  5. An advanced coarse-grained nucleosome core particle model for computer simulations of nucleosome-nucleosome interactions under varying ionic conditions.

    Directory of Open Access Journals (Sweden)

    Yanping Fan

    Full Text Available In the eukaryotic cell nucleus, DNA exists as chromatin, a compact but dynamic complex with histone proteins. The first level of DNA organization is the linear array of nucleosome core particles (NCPs. The NCP is a well-defined complex of 147 bp DNA with an octamer of histones. Interactions between NCPs are of paramount importance for higher levels of chromatin compaction. The polyelectrolyte nature of the NCP implies that nucleosome-nucleosome interactions must exhibit a great influence from both the ionic environment as well as the positively charged and highly flexible N-terminal histone tails, protruding out from the NCP. The large size of the system precludes a modelling analysis of chromatin at an all-atom level and calls for coarse-grained approximations. Here, a model of the NCP that include the globular histone core and the flexible histone tails described by one particle per each amino acid and taking into account their net charge is proposed. DNA wrapped around the histone core was approximated at the level of two base pairs represented by one bead (bases and sugar plus four beads of charged phosphate groups. Computer simulations, using a Langevin thermostat, in a dielectric continuum with explicit monovalent (K(+, divalent (Mg(2+ or trivalent (Co(NH(3(6 (3+ cations were performed for systems with one or ten NCPs. Increase of the counterion charge results in a switch from repulsive NCP-NCP interaction in the presence of K(+, to partial aggregation with Mg(2+ and to strong mutual attraction of all 10 NCPs in the presence of CoHex(3+. The new model reproduced experimental results and the structure of the NCP-NCP contacts is in agreement with available data. Cation screening, ion-ion correlations and tail bridging contribute to the NCP-NCP attraction and the new NCP model accounts for these interactions.

  6. Induced singularities of mass distributions of unstable particles connected with cascade decay and the CP-problem

    International Nuclear Information System (INIS)

    Khalfin, L.A.

    1975-01-01

    On the basis of the strong energy-momentum conservation law, the induced singularities of mass distributions of unstable particles connected with cascade decay are investigated. The possible solution of the CP-problem in the decay of Kaon neutral - Antikaon neutral mesons based on the mechanism of the induced singularities is proposed

  7. Curvature-induced microswarming and clustering of self-propelled particles

    Science.gov (United States)

    Bruss, Isaac; Glotzer, Sharon

    Non-equilibrium active matter systems exhibit many unique phenomena, such as motility-induced phase separation and swarming. However, little is known about how these behaviors depend on the geometry of the environment. To answer this question, we use Brownian dynamics simulations to study the effects of Gaussian curvature on self-propelled particles by confining them to the surface of a sphere. We find that a modest amount of curvature promotes phase separation by altering the shape of a cluster's boundary. Alternatively, particles on surfaces of high curvature experience reduced phase separation and instead form microswarms, where particles share a common orbit. We show that this novel flocking behavior is distinct from other previously studied examples, in that it is not explicitly incorporated into our model through Vicsek-like alignment rules nor torques. Rather, we find that microswarms emerge solely due to the geometric link between orientation and velocity, a property exclusive to surfaces with non-zero Gaussian curvature. These findings reveal the important role of local environment on the global emergent behavior of non-equilibrium systems. Center for Bio-Inspired Engineering (DOE Award # DE-SC0000989).

  8. A moving target for accelerated charged particle induced X-ray measurement

    International Nuclear Information System (INIS)

    Chuang, L.S.; Shima, K.; Ebihara, H.; Seki, R.; Mikumo, T.

    1980-01-01

    To attain good reproducibility as well as to enable an absolute determination in the measurement of X-ray fluorescences, resulting from bombardment of a heterogeneous sample by accelerated charged particles, a moving-target mechanism incorporating an electronic remote control system has been devised. The system is designed to scan the whole sample area with a chosen constant linear speed, by a fixed particle beam with a cross-sectional area a small fraction of that of the sample. Using 16 MeV protons and 40 MeV oxygen-ion beams, test runs of this system showed that the attempted objectives are attainable with good accuracies: reproducibility of the data for a given target is better than 3%, the linearity of the calibration curve is in good agreement, within the weighing errors of the standard elements and the uncertainty due to beam current fluctuation, with the expected values, and the results of absolute determinations using both metal foils and heterogeneous powder samples are in good agreement with accepted results using different methods. Detailed accounts of the moving-target system, and the test for reproducibility and linearity are presented. An absolute determination of the quantities related to accelerated charged-particle induced X-ray fluorescence (PIXE) using the moving target is presented for samples in different forms. (orig./HP)

  9. An optimised set-up for total reflection particle induced X-ray emission

    International Nuclear Information System (INIS)

    Kan, J.A. van; Vis, R.D.

    1997-01-01

    MeV proton beams at small angles of incidence (0-35 mrad) are used to analyse trace elements on flat surfaces such as Si wafers or quartz substrates. In these experiments, the particle induced X-ray emission (PIXE) signal is used in a new optimized set-up. This set-up is constructed in such a way that the X-ray detector can reach very large solid angles, larger than 1 sr. Use of these large detector solid angles, combined with the reduction of bremsstrahlung background, affords limits of detection (LOD) of the order of 10 10 at cm -2 using total reflection particle induced X-ray emission (TPIXE). The LODs from earlier TPIXE measurements in a non-optimized set-up are used to estimate LODs in the new TPIXE set-up. Si wafers with low surface concentrations of V, Ni, Cu and Ag are used as standards to calibrate the LODs found with this set-up. The metal concentrations are determined by total reflection X-ray fluorescence (TXRF). The TPIXE measurements are compared with TXRF measurements on the same wafers. (Author)

  10. Charged-particle induced thermonuclear reaction rates: a compilation for astrophysics

    International Nuclear Information System (INIS)

    Grama, Cornelia; Angulo, C.; Arnould, M.

    2000-01-01

    The rapidly growing wealth of nuclear data becomes less and less easily accessible to the astrophysics community. Mastering this volume of information and making it available in an accurate and usable form for incorporation into stellar evolution or nucleosynthesis models become urgent goals of prime necessity. we report on the results of the European network NACRE (Nuclear Astrophysics Compilation of REaction rates). The principal motivation for the setting-up of the NACRE network has been the necessity of building up a well-documented and detailed compilation of rates for charged-particle induced reactions on stable targets up to Si and on unstable nuclei of special significance in astrophysics. This work is meant to supersede the only existing compilation of reaction rates issued by Fowler and collaborators. The cross section data and/or resonance parameters for a total of 86 charged-particle induced reactions are given and the corresponding reaction rates are calculated and given in tabular form. When cross section data are not available in the whole needed range of energies, the theoretical predictions obtained in the framework of the Hauser-Feshbach model is used. Uncertainties are analyzed and realistic upper and lower bounds of the rates are determined. Reverse reaction rates and analytical approximations of the adopted rates are also provided. (authors)

  11. Charged-particle induced thermonuclear reaction rates: a compilation for astrophysics

    International Nuclear Information System (INIS)

    Grama, Cornelia

    1999-01-01

    The rapidly growing wealth of nuclear data becomes less and less easily accessible to the astrophysics community. Mastering this volume of information and making it available in an accurate and usable form for incorporation into stellar evolution or nucleosynthesis models become urgent goals of prime necessity. We report on the results of the European network NACRE (Nuclear Astrophysics Compilation of REaction rates). The principal motivation for the setting-up of the NACRE network has been the necessity of building up a well-documented and detailed compilation of rates for charged -particle induced reactions on stable targets up to Si and on unstable nuclei of special significance in astrophysics. This work is meant to supersede the only existing compilation of reaction rates issued by Fowler and collaborators. The cross section data and/or resonance parameters for a total of 86 charged-particle induced reactions are given and the corresponding reaction rates are calculated and given in tabular form. When cross section data are not available in the whole needed range of energies the theoretical predictions obtained in the framework of the Hauser-Feshbach model are used. Uncertainties are analyzed and realistic upper and lower bounds of the rates are determined. Reverse reaction rates and analytical approximations of the adopted rates are also provided. (author)

  12. Protection of cisplatin-induced spermatotoxicity, DNA damage and chromatin abnormality by selenium nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Rezvanfar, Mohammad Amin; Rezvanfar, Mohammad Ali [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Shahverdi, Ahmad Reza [Department of Pharmaceutical Biotechnology and Biotechnology Research Centre, Faculty of Pharmacy, TUMS, Tehran (Iran, Islamic Republic of); Ahmadi, Abbas [Department of Histology and Embryology, Faculty of Veterinary Medicine, Urmia University, Urmia (Iran, Islamic Republic of); Baeeri, Maryam; Mohammadirad, Azadeh [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: mohammad.abdollahi@utoronto.ca [Department of Toxicology and Pharmacology, Faculty of Pharmacy, and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Tehran (Iran, Islamic Republic of)

    2013-02-01

    Cisplatin (CIS), an anticancer alkylating agent, induces DNA adducts and effectively cross links the DNA strands and so affects spermatozoa as a male reproductive toxicant. The present study investigated the cellular/biochemical mechanisms underlying possible protective effect of selenium nano-particles (Nano-Se) as an established strong antioxidant with more bioavailability and less toxicity, on reproductive toxicity of CIS by assessment of sperm characteristics, sperm DNA integrity, chromatin quality and spermatogenic disorders. To determine the role of oxidative stress (OS) in the pathogenesis of CIS gonadotoxicity, the level of lipid peroxidation (LPO), antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and peroxynitrite (ONOO) as a marker of nitrosative stress (NS) and testosterone (T) concentration as a biomarker of testicular function were measured in the blood and testes. Thirty-two male Wistar rats were equally divided into four groups. A single IP dose of CIS (7 mg/kg) and protective dose of Nano-Se (2 mg/kg/day) were administered alone or in combination. The CIS-exposed rats showed a significant increase in testicular and serum LPO and ONOO level, along with a significant decrease in enzymatic antioxidants levels, diminished serum T concentration and abnormal histologic findings with impaired sperm quality associated with increased DNA damage and decreased chromatin quality. Coadministration of Nano-Se significantly improved the serum T, sperm quality, and spermatogenesis and reduced CIS-induced free radical toxic stress and spermatic DNA damage. In conclusion, the current study demonstrated that Nano-Se may be useful to prevent CIS-induced gonadotoxicity through its antioxidant potential. Highlights: ► Cisplatin (CIS) affects spermatozoa as a male reproductive toxicant. ► Effect of Nano-Se on CIS-induced spermatotoxicity was investigated. ► CIS-exposure induces oxidative sperm DNA damage

  13. A comparison of tackified, miniemulsion core-shell acrylic latex films with corresponding particle-blend films: structure-property relationships.

    Science.gov (United States)

    Canetta, Elisabetta; Marchal, Jeanne; Lei, Chun-Hong; Deplace, Fanny; König, Alexander M; Creton, Costantino; Ouzineb, Keltoum; Keddie, Joseph L

    2009-09-15

    Tackifying resins (TRs) are often added to pressure-sensitive adhesive films to increase their peel strength and adhesion energy. In waterborne adhesives, the TR is dispersed in water using surfactants and then blended with colloidal polymers in water (i.e., latex). In such waterborne systems, there are problems with the colloidal stability and difficulty in applying coatings of the particle blends; the films are often hydrophilic and subject to water uptake. Here, an alternative method of making waterborne, tackified adhesives is demonstrated. The TR is incorporated within the core of colloidal polymer particles via miniemulsion polymerization. Atomic force microscopy (AFM) combined with force spectroscopy analysis reveals there is heterogeneity in the distribution of the TR in films made from particle blends and also in films made from miniemulsion polymers. Two populations, corresponding to TR-rich and acrylic-rich components, were identified through analysis of the AFM force-displacement curves. The nanoscale maximum adhesion force and adhesion energy were found to be higher in a miniemulsion film containing 12 wt % tackifying resin in comparison to an equivalent blended film. The macroscale tack and viscoelasticity are interpreted by consideration of the nanoscale structure and properties. The incorporation of tackifying resin through a miniemulsion polymerization process not only offers clear benefits in the processing of the adhesive, but it also leads to enhanced adhesion properties.

  14. Particle-induced pulmonary acute phase response correlates with neutrophil influx linking inhaled particles and cardiovascular risk

    DEFF Research Database (Denmark)

    Saber, Anne Thoustrup; Lamson, Jacob Stuart; Jacobsen, Nicklas Raun

    2013-01-01

    We analysed the mRNA expression of Serum Amyloid A (Saa3) in lung tissue from female C57BL/6J mice exposed to different particles including nanomaterials (carbon black and titanium dioxide nanoparticles, multi- and single walled carbon nanotubes), diesel exhaust particles and airborne dust collected...... at a biofuel plant. Mice were exposed to single or multiple doses of particles by inhalation or intratracheal instillation and pulmonary mRNA expression of Saa3 was determined at different time points of up to 4 weeks after exposure. Also hepatic mRNA expression of Saa3, SAA3 protein levels in broncheoalveolar...... lavage fluid and in plasma and high density lipoprotein levels in plasma were determined in mice exposed to multiwalled carbon nanotubes. Results Pulmonary exposure to particles strongly increased Saa3 mRNA levels in lung tissue and elevated SAA3 protein levels in broncheoalveolar lavage fluid and plasma...

  15. Alpha particle induced DNA damage and repair in normal cultured thyrocytes of different proliferation status

    Energy Technology Data Exchange (ETDEWEB)

    Lyckesvärd, Madeleine Nordén, E-mail: madeleine.lyckesvard@oncology.gu.se [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden); Delle, Ulla; Kahu, Helena [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden); Lindegren, Sture [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg (Sweden); Jensen, Holger [The PET and Cyclotron Unit Copenhagen University Hospital, Rigshospitalet (Denmark); Bäck, Tom [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg (Sweden); Swanpalmer, John [Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg (Sweden); Elmroth, Kecke [Department of Oncology, Sahlgrenska Academy, University of Gothenburg (Sweden)

    2014-07-15

    Highlights: • We study DNA damage response to low-LET photons and high-LET alpha particles. • Cycling primary thyrocytes are more sensitive to radiation than stationary cells. • Influence of radiation quality varies due to cell cycle status of normal cells. • High-LET radiation gives rise to a sustained DNA damage response. - Abstract: Childhood exposure to ionizing radiation increases the risk of developing thyroid cancer later in life and this is suggested to be due to higher proliferation of the young thyroid. The interest of using high-LET alpha particles from Astatine-211 ({sup 211}At), concentrated in the thyroid by the same mechanism as {sup 131}I [1], in cancer treatment has increased during recent years because of its high efficiency in inducing biological damage and beneficial dose distribution when compared to low-LET radiation. Most knowledge of the DNA damage response in thyroid is from studies using low-LET irradiation and much less is known of high-LET irradiation. In this paper we investigated the DNA damage response and biological consequences to photons from Cobolt-60 ({sup 60}Co) and alpha particles from {sup 211}At in normal primary thyrocytes of different cell cycle status. For both radiation qualities the intensity levels of γH2AX decreased during the first 24 h in both cycling and stationary cultures and complete repair was seen in all cultures but cycling cells exposed to {sup 211}At. Compared to stationary cells alpha particles were more harmful for cycling cultures, an effect also seen at the pChk2 levels. Increasing ratios of micronuclei per cell nuclei were seen up to 1 Gy {sup 211}At. We found that primary thyrocytes were much more sensitive to alpha particle exposure compared with low-LET photons. Calculations of the relative biological effectiveness yielded higher RBE for cycling cells compared with stationary cultures at a modest level of damage, clearly demonstrating that cell cycle status influences the relative

  16. Inducing Strong Density Modulation with Small Energy Dispersion in Particle Beams and the Harmonic Amplifier Free Electron Laser

    CERN Document Server

    McNeil, Brian W J; Robb, Gordon

    2005-01-01

    We present a possible method of inducing a periodic density modulation in a particle beam with little increase in the energy dispersion of the particles. The flow of particles in phase space does not obey Liouville's Theorem. The method relies upon the Kuramoto-like model of collective synchronism found in free electron generators of radiation, such as Cyclotron Resonance Masers and the Free Electron Laser. For the case of an FEL interaction, electrons initially begin to bunch and emit radiation energy with a correlated energy dispersion which is periodic with the FEL ponderomotive potential. The relative phase between potential and particles is then changed by approximately 180 degrees. The particles continue to bunch, however, there is now a correlated re-absorption of energy from the field. We show that, by repeating this relative phase change many times, a significant density modulation of the particles may be achieved with only relatively small energy dispersion. A similar method of repeated relative ele...

  17. Cross section measurement of alpha particle induced nuclear reactions on natural cadmium up to 52 MeV

    OpenAIRE

    Ditrói, F.; Takács, S.; Haba, H.; Komori, Y.; Aikawa, M.

    2016-01-01

    Cross sections of alpha particle induced nuclear reactions have been measured on thin natural cadmium targets foils in the energy range from 11 to 51.2 MeV. This work was a part of our systematic study on excitation functions of light ion induced nuclear reactions on different target materials. Regarding the cross sections, the alpha induced reactions are not deeply enough investigated. Some of the produced isotopes are of medical interest, others have application in research and industry. Th...

  18. Induced charge of spherical dust particle on plasma-facing wall in non-uniform electric field

    International Nuclear Information System (INIS)

    Tomita, Y.; Smirnov, R.; Zhu, S.

    2005-01-01

    Induced charge of a spherical dust particle on a plasma-facing wall is investigated analytically, where non-uniform electric field is applied externally. The one-dimensional non-uniform electrostatic potential is approximated by the polynomial of the normal coordinate toward the wall. The bipolar coordinate is introduced to solve the Laplace equation of the induced electrostatic potential. The boundary condition at the dust surface determines the unknown coefficients of the general solution of the Laplace equation for the induced potential. From the obtained potential the surface induced charge can be calculated. This result allows estimating the effect of the surrounding plasma, which shields the induced charge. (author)

  19. Motorcycle exhaust particles induce airway inflammation and airway hyperresponsiveness in BALB/C mice.

    Science.gov (United States)

    Lee, Chen-Chen; Liao, Jiunn-Wang; Kang, Jaw-Jou

    2004-06-01

    A number of large studies have reported that environmental pollutants from fossil fuel combustion can cause deleterious effects to the immune system, resulting in an allergic reaction leading to respiratory tract damage. In this study, we investigated the effect of motorcycle exhaust particles (MEP), a major pollutant in the Taiwan urban area, on airway inflammation and airway hyperresponsiveness in laboratory animals. BALB/c mice were instilled intratracheally (i.t.) with 1.2 mg/kg and 12 mg/kg of MEP, which was collected from two-stroke motorcycle engines. The mice were exposed 3 times i.t. with MEP, and various parameters for airway inflammation and hyperresponsiveness were sequentially analyzed. We found that MEP would induce airway and pulmonary inflammation characterized by infiltration of eosinophils, neutrophils, lymphocytes, and macrophages in bronchoalveolar lavage fluid (BALF) and inflammatory cell infiltration in lung. In addition, MEP treatment enhanced BALF interleukin-4 (IL-4), IL-5, and interferon-gamma (IFN-gamma) cytokine levels and serum IgE production. Bronchial response measured by unrestrained plethysmography with methacholine challenge showed that MEP treatment induced airway hyperresponsiveness (AHR) in BALB/c mice. The chemical components in MEP were further fractionated with organic solvents, and we found that the benzene-extracted fraction exerts a similar biological effect as seen with MEP, including airway inflammation, increased BALF IL-4, serum IgE production, and induction of AHR. In conclusion, we present evidence showing that the filter-trapped particles emitted from the unleaded-gasoline-fueled two-stroke motorcycle engine may induce proinflammatory and proallergic response profiles in the absence of exposure to allergen.

  20. Dose response of micronuclei induced by combination radiation of α-particles and γ-rays in human lymphoblast cells

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Ruiping; He, Mingyuan; Dong, Chen; Xie, Yuexia; Ye, Shuang; Yuan, Dexiao [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China)

    2013-01-15

    Highlights: ► α-Particle induced MN had a biphasic dose–response followed by a bystander model. ► MN dose–response of α- and γ-combination IR was similar to that of α-particle. ► α-Particles followed by γ-rays yielded a synergistic effect on MN induction. ► Low dose γ-rays triggered antagonistic and adaptive responses against α-particle. - Abstract: Combination radiation is a real situation of both nuclear accident exposure and space radiation environment, but its biological dosimetry is still not established. This study investigated the dose–response of micronuclei (MN) induction in lymphocyte by irradiating HMy2.CIR lymphoblast cells with α-particles, γ-rays, and their combinations. Results showed that the dose–response of MN induced by γ-rays was well-fitted with the linear-quadratic model. But for α-particle irradiation, the MN induction had a biphasic phenomenon containing a low dose hypersensitivity characteristic and its dose response could be well-stimulated with a state vector model where radiation-induced bystander effect (RIBE) was involved. For the combination exposure, the dose response of MN was similar to that of α-irradiation. However, the yield of MN was closely related to the sequence of irradiations. When the cells were irradiated with α-particles at first and then γ-rays, a synergistic effect of MN induction was observed. But when the cells were irradiated with γ-rays followed by α-particles, an antagonistic effect of MN was observed in the low dose range although this combination radiation also yielded a synergistic effect at high doses. When the interval between two irradiations was extended to 4 h, a cross-adaptive response against the other irradiation was induced by a low dose of γ-rays but not α-particles.

  1. Core–shell structured FeSiAl/SiO{sub 2} particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} soft magnetic composite cores with tunable insulating layer thicknesses

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Xi’an, E-mail: groupfxa@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Wang, Jian, E-mail: snove418562@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Wu, Zhaoyang, E-mail: wustwuzhaoyang@163.com [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Li, Guangqiang, E-mail: ligq-wust@mail.wust.edu.cn [The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China); Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan, Hubei 430081 (China)

    2015-11-15

    Graphical abstract: - Highlights: • FeSiAl/SiO{sub 2} core–shell particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores were prepared. • SiO{sub 2} surrounding FeSiAl were replaced by Al{sub 2}O{sub 3} during sintering process. • Fe{sub 3}Si particles were separated by Al{sub 2}O{sub 3} with tunable thickness in composite cores. • Fe{sub 3}Si/Al{sub 2}O{sub 3} had lower core loss and better frequency stability than FeSiAl core. • The insulating layer between ferromagnetic particles can reduce core loss. - Abstract: FeSiAl/SiO{sub 2} core–shell particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores with tunable insulating layer thicknesses have been synthesized via a modified Stöber method combined with following high temperature sintering process. Most of the conductive FeSiAl particles could be coated by insulating SiO{sub 2} using the modified Stöber method. During the sintering process, the reaction 4Al + 3SiO{sub 2} ≣ 2α-Al{sub 2}O{sub 3} + 3Si took place and the new Fe{sub 3}Si/Al{sub 2}O{sub 3} composite was formed. The Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores displayed more excellent soft magnetic properties, better frequency stability at high frequencies, much higher resistivity and lower core loss than the raw FeSiAl core. Based on this, several types of FeSiAl/SiO{sub 2} particles and Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores with tunable insulating layer thicknesses were selectively prepared by simply varying TEOS contents. The thickness of Al{sub 2}O{sub 3} insulating layer and resistivity of Fe{sub 3}Si/Al{sub 2}O{sub 3} composite cores increased with increasing the TEOS contents, while the permeability and core loss changed in the opposite direction.

  2. The lasting effect of limonene-induced particle formation on air quality in a genuine indoor environment.

    Science.gov (United States)

    Rösch, Carolin; Wissenbach, Dirk K; von Bergen, Martin; Franck, Ulrich; Wendisch, Manfred; Schlink, Uwe

    2015-09-01

    Atmospheric ozone-terpene reactions, which form secondary organic aerosol (SOA) particles, can affect indoor air quality when outdoor air mixes with indoor air during ventilation. This study, conducted in Leipzig, Germany, focused on limonene-induced particle formation in a genuine indoor environment (24 m(3)). Particle number, limonene and ozone concentrations were monitored during the whole experimental period. After manual ventilation for 30 min, during which indoor ozone levels reached up to 22.7 ppb, limonene was introduced into the room at concentrations of approximately 180 to 250 μg m(-3). We observed strong particle formation and growth within a diameter range of 9 to 50 nm under real-room conditions. Larger particles with diameters above 100 nm were less affected by limonene introduction. The total particle number concentrations (TPNCs) after limonene introduction clearly exceed outdoor values by a factor of 4.5 to 41 reaching maximum concentrations of up to 267,000 particles cm(-3). The formation strength was influenced by background particles, which attenuated the formation of new SOA with increasing concentration, and by ozone levels, an increase of which by 10 ppb will result in a six times higher TPNC. This study emphasizes indoor environments to be preferred locations for particle formation and growth after ventilation events. As a consequence, SOA formation can produce significantly higher amounts of particles than transported by ventilation into the indoor air.

  3. A Massive, Cooling-Flow-Induced Starburst in the Core of a Highly Luminous Galaxy Cluster

    Science.gov (United States)

    McDonald, M.; Bayliss, M.; Benson, B. A.; Foley, R. J.; Ruel, J.; Sullivan, P.; Veilleux, S.; Aird, K. A.; Ashby, M. L. N.; Bautz, M.; hide

    2012-01-01

    In the cores of some galaxy clusters the hot intracluster plasma is dense enough that it should cool radiatively in the cluster s lifetime, leading to continuous "cooling flows" of gas sinking towards the cluster center, yet no such cooling flow has been observed. The low observed star formation rates and cool gas masses for these "cool core" clusters suggest that much of the cooling must be offset by astrophysical feedback to prevent the formation of a runaway cooling flow. Here we report X-ray, optical, and infrared observations of the galaxy cluster SPT-CLJ2344-4243 at z = 0.596. These observations reveal an exceptionally luminous (L(sub 2-10 keV) = 8.2 10(exp 45) erg/s) galaxy cluster which hosts an extremely strong cooling flow (M(sub cool) = 3820 +/- 530 Stellar Mass/yr). Further, the central galaxy in this cluster appears to be experiencing a massive starburst (740 +/- 160 Stellar Mass/ yr), which suggests that the feedback source responsible for preventing runaway cooling in nearby cool core clusters may not yet be fully established in SPT-CLJ2344-4243. This large star formation rate implies that a significant fraction of the stars in the central galaxy of this cluster may form via accretion of the intracluster medium, rather than the current picture of central galaxies assembling entirely via mergers.

  4. Studies of Deteriorated Heat Transfer in Prismatic Cores Stemming from Irradiation-Induced Geometry Distortion

    International Nuclear Information System (INIS)

    Williams, Brian G.; Schultz, Richard R.; McEligot, Don M.; McCreery, Glenn

    2015-01-01

    A reference design for the Next Generation Nuclear Plant (NGNP) is to use General Atomics Modular High Temperature Gas-cooled Reactor (MHTGR). For such a configuration in normal operation, the helium coolant flow proceeds from the upper plenum to the lower plenum principally through the core coolant channels and the interstitial gaps (bypass flow) that separate the prismatic blocks from one another. Only the core prismatic blocks have coolant channels. The interstitial gaps are present throughout the core, the inner reflector region, and the out reflector region. The bypass flows in a prismatic gas-cooled reactor (GCR) are of potential concern because they reduce the desired flow rates in the coolant channels and, thereby, can increase outlet gas temperatures and maximum fuel temperatures. Consequently, it is appropriate to account for bypass flows in reactor thermal gas dynamic analyses. The objectives of this project include the following: fundamentally understand bypass flow and heat transfer at scaled, undistorted conditions and with geometry distortions; develop improved estimates of associated loss coefficients, surface friction and heat transfer for systems and network codes; and obtain related data for validation of CFD (computational fluid dynamic) or system (e.g., RELAP5) codes which can be employed in predictions for a GCR for normal power, reduced power, and residual heat removal operations.

  5. Studies of Deteriorated Heat Transfer in Prismatic Cores Stemming from Irradiation-Induced Geometry Distortion

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Brian G. [Idaho State Univ., Pocatello, ID (United States); Schultz, Richard R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); McEligot, Don M. [Univ. of Idaho, Moscow, ID (United States); McCreery, Glenn [Battelle Energy Alliance, LLC, Idaho Falls, ID (United States)

    2015-08-31

    A reference design for the Next Generation Nuclear Plant (NGNP) is to use General Atomics Modular High Temperature Gas-cooled Reactor (MHTGR). For such a configuration in normal operation, the helium coolant flow proceeds from the upper plenum to the lower plenum principally through the core coolant channels and the interstitial gaps (bypass flow) that separate the prismatic blocks from one another. Only the core prismatic blocks have coolant channels. The interstitial gaps are present throughout the core, the inner reflector region, and the out reflector region. The bypass flows in a prismatic gas-cooled reactor (GCR) are of potential concern because they reduce the desired flow rates in the coolant channels and, thereby, can increase outlet gas temperatures and maximum fuel temperatures. Consequently, it is appropriate to account for bypass flows in reactor thermal gas dynamic analyses. The objectives of this project include the following: fundamentally understand bypass flow and heat transfer at scaled, undistorted conditions and with geometry distortions; develop improved estimates of associated loss coefficients, surface friction and heat transfer for systems and network codes; and obtain related data for validation of CFD (computational fluid dynamic) or system (e.g., RELAP5) codes which can be employed in predictions for a GCR for normal power, reduced power, and residual heat removal operations.

  6. A novel synthesis method for TiO2 particles with magnetic Fe3O4 cores.

    Science.gov (United States)

    Dong, Qi; Zhang, Keqiang; An, Yi

    2014-01-01

    TiO2@(AC/Fe3O4) (AC is activated carbon) was prepared by using AC and Fe3O4 as joint support. The morphological features, crystal structure, and magnetism of the final product were characterized. The results indicate that TiO2 particles formed on the surface of AC and Fe3O4; the sizes of TiO2 and Fe3O4 were 0.5 and 0.7 μm respectively, and that of AC fell within a wide range. The highly crystalline cubic structures of the TiO2 particles was in accord with the standard X-ray diffractometry spectrum of magnetite and anatase. The maximum saturation magnetization of TiO2@(AC/Fe3O4) was 75 emu g(-1), which was enough to support magnetic recovery. The rate of methylene blue (MB) removal photocatalyzed by TiO2@(AC/Fe3O4) was higher by 50% than that achieved with AC/Fe3O4 photocatalysis, and similar to that achieved with TiO2@AC. The removal rate (kobs) decreased drastically from 1.77 × 10(-2) to 9.36 × 10(-3)min(-1) when the initial concentration of MB solution increased from 2.0 to 5.0 mg L(-1). The kobs value increased from 9.41 × 10(-3) to 1.34 × 10(-2)min(-1) with increasing photocatalyst dosage from 0.2 to 1.0 g, then slightly decreased to 1.33 × 10(-2)min(-1) at 2.0 g dosage.

  7. When are active Brownian particles and run-and-tumble particles equivalent? Consequences for motility-induced phase separation

    OpenAIRE

    Cates, M. E.; Tailleur, J.

    2012-01-01

    Active Brownian particles (ABPs, such as self-phoretic colloids) swim at fixed speed $v$ along a body-axis ${\\bf u}$ that rotates by slow angular diffusion. Run-and-tumble particles (RTPs, such as motile bacteria) swim with constant $\\u$ until a random tumble event suddenly decorrelates the orientation. We show that when the motility parameters depend on density $\\rho$ but not on ${\\bf u}$, the coarse-grained fluctuating hydrodynamics of interacting ABPs and RTPs can be mapped onto each other...

  8. Effects of Alloying Elements on the Formation of Core-Shell-Structured Reinforcing Particles during Heating of Al–Ti Powder Compacts

    Science.gov (United States)

    Chen, Tijun; Gao, Min; Tong, Yunqi

    2018-01-01

    To prepare core-shell-structured Ti@compound particle (Ti@compoundp) reinforced Al matrix composite via powder thixoforming, the effects of alloying elements, such as Si, Cu, Mg, and Zn, on the reaction between Ti powders and Al melt, and the microstructure of the resulting reinforcements were investigated during heating of powder compacts at 993 K (720 °C). Simultaneously, the situations of the reinforcing particles in the corresponding semisolid compacts were also studied. Both thermodynamic analysis and experiment results all indicate that Si participated in the reaction and promoted the formation of Al–Ti–Si ternary compounds, while Cu, Mg, and Zn did not take part in the reaction and facilitated Al3Ti phase to form to different degrees. The first-formed Al–Ti–Si ternary compound was τ1 phase, and then it gradually transformed into (Al,Si)3Ti phase. The proportion and existing time of τ1 phase all increased as the Si content increased. In contrast, Mg had the largest, Cu had the least, and Si and Zn had an equivalent middle effect on accelerating the reaction. The thicker the reaction shell was, the larger the stress generated in the shell was, and thus the looser the shell microstructure was. The stress generated in (Al,Si)3Ti phase was larger than that in τ1 phase, but smaller than that in Al3Ti phase. So, the shells in the Al–Ti–Si system were more compact than those in the other systems, and Si element was beneficial to obtain thick and compact compound shells. Most of the above results were consistent to those in the semisolid state ones except the product phase constituents in the Al–Ti–Mg system and the reaction rate in the Al–Ti–Zn system. More importantly, the desirable core-shell structured Ti@compoundp was only achieved in the semisolid Al–Ti–Si system. PMID:29342946

  9. Effects of Alloying Elements on the Formation of Core-Shell-Structured Reinforcing Particles during Heating of Al-Ti Powder Compacts.

    Science.gov (United States)

    Chen, Tijun; Gao, Min; Tong, Yunqi

    2018-01-15

    To prepare core-shell-structured Ti@compound particle (Ti@compound p ) reinforced Al matrix composite via powder thixoforming, the effects of alloying elements, such as Si, Cu, Mg, and Zn, on the reaction between Ti powders and Al melt, and the microstructure of the resulting reinforcements were investigated during heating of powder compacts at 993 K (720 °C). Simultaneously, the situations of the reinforcing particles in the corresponding semisolid compacts were also studied. Both thermodynamic analysis and experiment results all indicate that Si participated in the reaction and promoted the formation of Al-Ti-Si ternary compounds, while Cu, Mg, and Zn did not take part in the reaction and facilitated Al₃Ti phase to form to different degrees. The first-formed Al-Ti-Si ternary compound was τ1 phase, and then it gradually transformed into (Al,Si)₃Ti phase. The proportion and existing time of τ1 phase all increased as the Si content increased. In contrast, Mg had the largest, Cu had the least, and Si and Zn had an equivalent middle effect on accelerating the reaction. The thicker the reaction shell was, the larger the stress generated in the shell was, and thus the looser the shell microstructure was. The stress generated in (Al,Si)₃Ti phase was larger than that in τ1 phase, but smaller than that in Al₃Ti phase. So, the shells in the Al-Ti-Si system were more compact than those in the other systems, and Si element was beneficial to obtain thick and compact compound shells. Most of the above results were consistent to those in the semisolid state ones except the product phase constituents in the Al-Ti-Mg system and the reaction rate in the Al-Ti-Zn system. More importantly, the desirable core-shell structured Ti@compound p was only achieved in the semisolid Al-Ti-Si system.

  10. Nanoparticles of lipid monolayer shell and biodegradable polymer core for controlled release of paclitaxel: effects of surfactants on particles size, characteristics and in vitro performance.

    Science.gov (United States)

    Liu, Yutao; Pan, Jie; Feng, Si-Shen

    2010-08-16

    This work developed a system of nanoparticles of lipid monolayer shell and biodegradable polymer core for controlled release of anticancer drugs with paclitaxel as a model drug, in which the emphasis was given to the effects of the surfactant type and the optimization of the emulsifier amount used in the single emulsion solvent evaporation/extraction process for the nanoparticle preparation on the particle size, characters and in vitro performance. The drug loaded nanoparticles were characterized by laser light scattering (LLS) for size and size distribution, field-emission scanning electron microscopy (FESEM) for surface morphology, X-ray photoelectron spectroscopy (XPS) for surface chemistry, zetasizer for surface charge, and high performance liquid chromatography (HPLC) for drug encapsulation efficiency and in vitro drug release kinetics. MCF-7 breast cancer cells were employed to evaluate the cellular uptake and cytotoxicity. It was found that phospholipids of short chains such as 1,2-dilauroylphosphatidylocholine (DLPC) have great advantages over the traditional emulsifier poly(vinyl alcohol) (PVA), which is used most often in the literature, in preparation of nanoparticles of biodegradable polymers such as poly(D,L-lactide-co-glycolide) (PLGA) for desired particle size, character and in vitro cellular uptake and cytotoxicity. After incubation with MCF-7 cells at 0.250 mg/ml NP concentration, the coumarin-6 loaded PLGA NPs of DLPC shell showed more effective cellular uptake versus those of PVA shell. The analysis of IC(50), i.e. the drug concentration at which 50% of the cells are killed, demonstrated that our DLPC shell PLGA core NP formulation of paclitaxel could be 5.88-, 5.72-, 7.27-fold effective than the commercial formulation Taxol after 24, 48, 72h treatment, respectively. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  11. Vibration-induced particle formation during yogurt fermentation - Industrial vibration measurements and development of an experimental setup.

    Science.gov (United States)

    Körzendörfer, Adrian; Temme, Philipp; Nöbel, Stefan; Schlücker, Eberhard; Hinrichs, Jörg

    2016-07-01

    The aim of the study was to investigate the effects of vibrations during yogurt fermentation. Machinery such as pumps and switching valves generate vibrations that may disturb the gelation by inducing large particles. Oscillation measurements on an industrial yogurt production line showed that oscillations are transferred from pumps right up to the fermentation tanks. An experimental setup (20L) was developed to study the effect of vibrations systematically. The fermenters were decoupled with air springs to enable reference fermentations under idle conditions. A vibration exciter was used to stimulate the fermenters. Frequency sweeps (25-1005Hz, periodic time 10s) for 20min from pH5.4 induced large particles. The number of visible particles was significantly increased from 35±4 (reference) to 89±9 particles per 100g yogurt. Rheological parameters of the stirred yogurt samples were not influenced by vibrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Light charged particle production in fast neutron-induced reactions on carbon (En=40 to 75 MeV) (II). Tritons and alpha particles

    International Nuclear Information System (INIS)

    Dufauquez, C.; Slypen, I.; Benck, S.; Meulders, J.P.; Corcalciuc, V.

    2000-01-01

    Double-differential cross sections for fast neutron-induced triton and alpha-particle production on carbon are reported at six incident neutron energies between 40 and 75 MeV. Angular distributions were measured at laboratory angles between 20 deg. and 160 deg. . Energy-differential, angle-differential and total cross sections are also reported. Experimental cross sections are compared to existing experimental data and to theoretical model calculations

  13. Core Cross-Linked Multiarm Star Polymers with Aggregation-Induced Emission and Temperature Responsive Fluorescence Characteristics

    KAUST Repository

    Zhang, Zhen

    2017-05-19

    Aggregation-induced emission (AIE) active core cross-linked multiarm star polymers, carrying polystyrene (PS), polyethylene (PE), or polyethylene-b-polycaprolactone (PE-b-PCL) arms, have been synthesized through an “arm-first” strategy, by atom transfer radical copolymerization (ATRP) of a double styrene-functionalized tetraphenylethene (TPE-2St) used as a cross-linker with linear arm precursors possessing terminal ATRP initiating moieties. Polyethylene macroinitiator (PE–Br) was prepared via the polyhomologation of dimethylsulfoxonium methylide with triethylborane followed by oxidation/hydrolysis and esterification of the produced PE–OH with 2-bromoisobutyryl bromide; polyethylene-block-poly(ε-caprolactone) diblock macroinitiator was derived by combining polyhomologation with ring-opening polymerization (ROP). All synthesized star polymers showed AIE-behavior either in solution or in bulk. At high concentration in good solvents (e.g., THF, or toluene) they exhibited low photoluminescence (PL) intensity due to the inner filter effect. In sharp contrast to the small molecule TPE-2St, the star polymers were highly emissive in dilute THF solutions. This can be attributed to the cross-linked structure of poly(TPE-2St) core which restricts the intramolecular rotation and thus induces emission. In addition, the PL intensity of PE star polymers in THF(solvent)/n-hexane(nonsolvent) mixtures, due to their nearly spherical shape, increased when the temperature decreased from 55 to 5 °C with a linear response in the range 40–5 °C.

  14. Biological Fate of Fe3O4 Core-Shell Mesoporous Silica Nanoparticles Depending on Particle Surface Chemistry

    Science.gov (United States)

    Rascol, Estelle; Daurat, Morgane; Da Silva, Afitz; Maynadier, Marie; Dorandeu, Christophe; Charnay, Clarence; Garcia, Marcel; Lai-Kee-Him, Joséphine; Bron, Patrick; Auffan, Mélanie; Angeletti, Bernard; Devoisselle, Jean-Marie; Guari, Yannick; Gary-Bobo, Magali; Chopineau, Joël

    2017-01-01

    The biological fate of nanoparticles (NPs) for biomedical applications is highly dependent of their size and charge, their aggregation state and their surface chemistry. The chemical composition of the NPs surface influences their stability in biological fluids, their interaction with proteins, and their attraction to the cell membranes. In this work, core-shell magnetic mesoporous silica nanoparticles (Fe3O4@MSN), that are considered as potential theranostic candidates, are coated with polyethylene glycol (PEG) or 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) lipid bilayer. Their biological fate is studied in comparison to the native NPs. The physicochemical properties of these three types of NPs and their suspension behavior in different media are investigated. The attraction to a membrane model is also evaluated using a supported lipid bilayer. The surface composition of NPs strongly influences their dispersion in biological fluids mimics, protein binding and their interaction with cell membrane. While none of these types of NPs is found to be toxic on mice four days after intravenous injection of a dose of 40 mg kg−1 of NPs, their surface coating nature influences the in vivo biodistribution. Importantly, NP coated with DMPC exhibit a strong accumulation in liver and a very low accumulation in lung in comparison with nude or PEG ones. PMID:28665317

  15. High mobility group protein number17 cross-links primarily to histone H2A in the reconstituted HMG 17 - nucleosome core particle complex

    International Nuclear Information System (INIS)

    Cook, G.R.; Yau, P.; Yasuda, H.; Traut, R.R.; Bradbury, E.M.

    1986-01-01

    The neighbor relationship of lamb thymus High Mobility Group (HMG) protein 17 to native HeLa nucleosome core particle histones in the reconstituted complex has been studied. 125 I-labeled HMG 17 was cross-linking to core histones using the protein-protein cross-linking reagent 2-iminothiolane. Specific cross-linked products were separated on a two-dimensional Triton-acid-urea/SDS gel system, located by autoradiography, excised and quantified. Disulfide bonds in the cross links were then cleaved and the protein constituents were identified by SDS gel electrophoresis. HMG 17 cross-linked primarily to histone H2A while lower levels of cross-linking occurred between HMG 17 and the other histones. In contrast, cross-linking between two HMG 17 molecules bound on the same nucleosome was relatively rare. It is concluded that the same nucleosome was relatively rare. It is concluded that H2A comprises part of the HMG 17 binding site but that HMG 17 is sufficiently elongated and mobile to permit cross-linking to the other histones and to a second HMG 17 molecule. These results are in agreement with the current model for the structure of the nucleosome and the proposed binding sites for HMG 17

  16. Measurement-induced-nonlocality for Dirac particles in Garfinkle–Horowitz–Strominger dilation space–time

    Energy Technology Data Exchange (ETDEWEB)

    He, Juan [School of Physics & Material Science, Anhui University, Hefei, 230601 (China); School of Physics & Electronics Science, Fuyang Normal College, Fuyang, 236037 (China); Xu, Shuai [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Ye, Liu, E-mail: yeliu@ahu.edu.cn [School of Physics & Material Science, Anhui University, Hefei, 230601 (China)

    2016-05-10

    We investigate the quantum correlation via measurement-induced-nonlocality (MIN) for Dirac particles in Garfinkle–Horowitz–Strominger (GHS) dilation space–time. It is shown that the physical accessible quantum correlation decreases as the dilation parameter increases monotonically. Unlike the case of scalar fields, the physical accessible correlation is not zero when the Hawking temperature is infinite owing to the Pauli exclusion principle and the differences between Fermi–Dirac and Bose–Einstein statistics. Meanwhile, the boundary of MIN related to Bell-violation is derived, which indicates that MIN is more general than quantum nonlocality captured by the violation of Bell-inequality. As a by-product, a tenable quantitative relation about MIN redistribution is obtained whatever the dilation parameter is. In addition, it is worth emphasizing that the underlying reason why the physical accessible correlation and mutual information decrease is that they are redistributed to the physical inaccessible regions.

  17. Trace element determination in tomato puree using particle induced X-ray emission and Rutherford backscattering

    International Nuclear Information System (INIS)

    Romero-Davila, E.; Miranda, J.

    2004-01-01

    Particle induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) were used to determine the concentrations of trace elements in samples of 12 tomato puree brands sold in the Mexican market. While RBS offered information about the main elements present in the matrix, PIXE gave results on trace elements. As a whole, data for 17 elements (C, N, O, Na, Mg, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn) were obtained. To evaluate the results, a comparison with brands from USA, Japan, Colombia, and Chile was carried out, using tomato purees produced following the domestic technology recipe. Additionally, the results were considered in the light of the Codex Alimentarius and the Mexican standard. It was found that all of the brands fall within the limits established by these standards, being of the same order of magnitude as the foreign brands. (author)

  18. Detection of halogenated flame retardants in polyurethane foam by particle induced X-ray emission

    International Nuclear Information System (INIS)

    Maley, Adam M.; Falk, Kyle A.; Hoover, Luke; Earlywine, Elly B.; Seymour, Michael D.; DeYoung, Paul A.; Blum, Arlene; Stapleton, Heather M.; Peaslee, Graham F.

    2015-01-01

    A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography–Mass Spectrometry (GC–MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC–MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams

  19. Particle induced x-ray emission studies of some Indian medicinal plants

    International Nuclear Information System (INIS)

    Nomita Devi, K.; Nandakumar Sarma, H.; Kumar, Sanjiv

    2007-01-01

    Medicinal herbs have been used from antiquity by humanity. This paper discusses the elemental composition and concentration of ten Indian medicinal plants investigated by particle induced X-ray emission (PIXE) technique. The accuracy and precision of the technique were assured by analyzing three Certified Standard Reference Materials -cabbage- (GBW 08504, China), wheat flour (NIST-8436) and bovine liver (NIST-1577b). The element K, Ca, Mn, Fe, Cu and Zn were found to be present in all the samples in varying concentrations. No toxic heavy metals such as As, Pb and Hg were detected in the studied plants. The range of the elemental concentrations in dry weight has been found to vary from 4.69x10 4 mg/kg to 1.81 mg/kg in the plants. The results also show that these plants contain elements of vital importance in man's metabolism and that are needed for growth and developments, prevention and heating of diseases. (author)

  20. Quantification of arsenic in activated carbon using particle induced X-ray emission

    International Nuclear Information System (INIS)

    Yadav, Nirbhay N.; Maheswaran, Saravanamuthu; Shutthanandan, Vaithiyalingam; Thevuthasan, Suntharampillai; Ngo, Huu H.; Vigneswaran, Saravanamuth

    2006-01-01

    To date, the trace elemental analysis of solids with inhomogeneous internal structure has been limited, particularly in the case of adsorbents. High-energy ion beam based particle induced X-ray emission (PIXE) is an ideal analytical tool suitable for simultaneous quantification of trace elements with high accuracy. In this study, PIXE was used to quantify arsenic in the adsorbents, granular activated carbon (GAC) and powder activated carbon (PAC). Pelletized and unmodified GAC and PAC samples were analyzed along with powder samples deposited on thin teflon filters. These sample preparation methods resulted in samples of various thicknesses and densities. PIXE measurements taken from these samples were compared to results from neutron activation analysis (NAA) and atomic absorption spectroscopy (AAS). There is a good agreement between the values from the NAA and pelletized PIXE measurements and some AAS measurements

  1. Bubbling behavior of a fluidized bed of fine particles caused by vibration-induced air inflow.

    Science.gov (United States)

    Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi

    2013-01-01

    We demonstrate that a vibration-induced air inflow can cause vigorous bubbling in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of bubbles that rise and eventually burst at the top surface of the powder bed. A negative pressure is created below the rising bubbles. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously bubbling fluidized bed that does not require the use of an external air supply system.

  2. Particle Induced X-ray Emission (PIXE) Approach for the Quantification of Thin Al Films

    International Nuclear Information System (INIS)

    Younes, G; Zahraman, K; Nsouli, B; Soueidan, M; Ferro, G

    2008-01-01

    Particle Induced X-ray Emission (PIXE) has been used as a fast and non-destructive technique for sensitive characterization of ultra thin Al films deposited by evaporation onto Si substrate. In this work the PIXE technique was optimized, using proton beam at different energies and different angles of incidence, for the characterization of ultra thin Al films (few nanometers) deposited onto Si substrate. The PIXE results showed that a proton beam of 300 keV under tilting angle of 80 degree permits an accurate determination of Al with high sensitivity within few minutes of acquisition time and a LOD of less than 0.2 nm. The LOD versus energy and tilting angle will be presented and discussed. (author)

  3. Consistent interpretation of neutron-induced charged-particle emission in silicon

    International Nuclear Information System (INIS)

    Hermsdorf, D.

    1982-06-01

    Users requesting gas production cross sections for Silicon will be confronted with serious discrepancies taking evaluated data as well as experimental ones. To clarify the accuracies achieved at present in experiments and evaluations in this paper an intercomparison of different evaluated nuclear data files has been carried out resulting in recommendations for improvements of these files. The analysis of the experimental data base also shows contradictory measurements or in most cases a lack of data. So an interpretation of reliable measured data in terms of nuclear reaction theories has been done using statistical and direct reaction mechanism models. This study results in a consistent and comprehensive evaluated data set for neutron-induced charged-particle production in Silicon which will be incorporated in file 2015 of the SOKRATOR library. (author)

  4. Application of chaos theory to the particle dynamics of asymmetry-induced transport

    Science.gov (United States)

    Eggleston, D. L.

    2018-03-01

    The techniques of chaos theory are employed in an effort to better understand the complex single-particle dynamics of asymmetry-induced transport in non-neutral plasmas. The dynamical equations are re-conceptualized as describing time-independent trajectories in a four-dimensional space consisting of the radius r, rotating frame angle ψ, axial position z, and axial velocity v. Results include the identification of an integral of the motion, fixed-point analysis of the dynamical equations, the construction and interpretation of Poincaré sections to visualize the dynamics, and, for the case of chaotic motion, numerical calculation of the largest Lyapunov exponent. Chaotic cases are shown to be associated with the overlap of resonance islands formed by the applied asymmetry.

  5. Detection of halogenated flame retardants in polyurethane foam by particle induced X-ray emission

    Energy Technology Data Exchange (ETDEWEB)

    Maley, Adam M.; Falk, Kyle A.; Hoover, Luke; Earlywine, Elly B.; Seymour, Michael D. [Department of Chemistry, Hope College, 35 E. 12th Street, Holland, MI 49423 (United States); DeYoung, Paul A. [Department of Physics, Hope College, 27 Graves Place, Holland, MI 49423 (United States); Blum, Arlene [Green Science Policy Institute, Box 5455, Berkeley, CA 94705 (United States); Stapleton, Heather M. [Nicholas School of the Environment, Duke University, LSRC Box 90328, Durham, NC 27708 (United States); Peaslee, Graham F., E-mail: peaslee@hope.edu [Department of Chemistry, Hope College, 35 E. 12th Street, Holland, MI 49423 (United States)

    2015-09-01

    A novel application of particle-induced X-ray emission (PIXE) has been developed to detect the presence of chlorinated and brominated flame retardant chemicals in polyurethane foams. Traditional Gas Chromatography–Mass Spectrometry (GC–MS) methods for the detection and identification of halogenated flame retardants in foams require extensive sample preparation and data acquisition time. The elemental analysis of the halogens in polyurethane foam performed by PIXE offers the opportunity to identify the presence of halogenated flame retardants in a fraction of the time and sample preparation cost. Through comparative GC–MS and PIXE analysis of 215 foam samples, excellent agreement between the two methods was obtained. These results suggest that PIXE could be an ideal rapid screening method for the presence of chlorinated and brominated flame retardants in polyurethane foams.

  6. R-Matrix Codes for Charged-particle Induced Reactionsin the Resolved Resonance Region

    Energy Technology Data Exchange (ETDEWEB)

    Leeb, Helmut [Technical Univ. of Wien, Vienna (Austria); Dimitriou, Paraskevi [Intl Atomic Energy Agency (IAEA), Vienna (Austria); Thompson, Ian J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-01-01

    A Consultant’s Meeting was held at the IAEA Headquarters, from 5 to 7 December 2016, to discuss the status of R-matrix codes currently used in calculations of charged-particle induced reaction cross sections at low energies. The meeting was a follow-up to the R-matrix Codes meeting held in December 2015, and served the purpose of monitoring progress in: the development of a translation code to enable exchange of input/output parameters between the various codes in different formats, fitting procedures and treatment of uncertainties, the evaluation methodology, and finally dissemination. The details of the presentations and technical discussions, as well as additional actions that were proposed to achieve all the goals of the meeting are summarized in this report.

  7. Development of a Reference Database for Particle-Induced Gamma-ray Emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dimitriou, P., E-mail: P.Dimitriou@iaea.org [International Atomic Energy Agency, Wagramerstrasse 5, A-1400 Vienna (Austria); Becker, H.-W. [Ruhr Universität Bochum, Gebäude NT05/130, Postfach 102148, Bochum 44721 (Germany); Bogdanović-Radović, I. [Department of Experimental Physics, Institute Rudjer Boskovic, Bijenicka Cesta 54, 10000 Zagreb (Croatia); Chiari, M. [Istituto Nazionale di Fisica Nucleare, Via Sansone 1, Sesto Fiorentino, 50019 Firenze (Italy); Goncharov, A. [Kharkov Institute of Physics and Technology, National Science Center, Akademicheskaya Str.1, Kharkov 61108 (Ukraine); Jesus, A.P. [Departamento de Física, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa (Portugal); Kakuee, O. [Nuclear Science and Technology Research Institute, End of North Karegar Ave., PO Box 14395-836, Tehran (Iran, Islamic Republic of); Kiss, A.Z. [Institute of Nuclear Research (ATOMKI), Bem ter 18/c, PO Box 51, 4001 Debrecen (Hungary); Lagoyannis, A. [National Center of Scientific Research “Demokritos”, Agia Paraskevi, P.O. Box 60228, 15310 Athens (Greece); Räisänen, J. [Division of Materials Physics, Department of Physics, University of Helsinki, PO Box 43, 00014 University of Helsinki (Finland); Strivay, D. [Institut de Physique Nucleaire, Atomique et de Spectroscopie, Universite de Liège, Sart Tilman, B15 4000 Liège (Belgium); Zucchiatti, A. [Centro de Micro Análisis de Materiales, Universidad Autónoma de Madrid, Faraday 3, Madrid 28049 (Spain)

    2016-03-15

    Particle-Induced Gamma-ray Emission (PIGE) is a powerful analytical technique that exploits the interactions of rapid charged particles with nuclei located near a sample surface to determine the composition and structure of the surface regions of solids by measurement of characteristic prompt γ rays. The potential for depth profiling of this technique has long been recognized, however, the implementation has been limited owing to insufficient knowledge of the physical data and lack of suitable user-friendly computer codes for the applications. Although a considerable body of published data exists in the nuclear physics literature for nuclear reaction cross sections with γ rays in the exit channel, there is no up-to-date, comprehensive compilation specifically dedicated to IBA applications. A number of PIGE cross-section data had already been uploaded to the Ion Beam Analysis Nuclear Data Library (IBANDL) ( (http://www-nds.iaea.org/ibandl)) by members of the IBA community by 2011, however a preliminary survey of this body of unevaluated experimental data has revealed numerous discrepancies beyond the uncertainty limits reported by the authors. Using the resources and coordination provided by the IAEA, a concerted effort to improve the situation was made within the Coordinated Research Project on the Development of a Reference Database for PIGE spectroscopy, from 2011 to 2015. The aim of the CRP was to create a data library for Ion Beam Analysis that contains reliable and usable data on charged particle γ-ray emission cross sections that would be made freely available to the user community. As the CRP has reached its completion, we shall present its main achievements, including the results of nuclear cross-section evaluations and the development of a computer code that will become available to the public allowing for the implementation of a standardless PIGE technique.

  8. Venezuelan Equine Encephalitis Replicon Particles Can Induce Rapid Protection against Foot-and-Mouth Disease Virus

    Science.gov (United States)

    Diaz-San Segundo, Fayna; Dias, Camila C. A.; Moraes, Mauro P.; Weiss, Marcelo; Perez-Martin, Eva; Owens, Gary; Custer, Max; Kamrud, Kurt; de los Santos, Teresa

    2013-01-01

    We have previously shown that delivery of the porcine type I interferon gene (poIFN-α/β) with a replication-defective human adenovirus vector (adenovirus 5 [Ad5]) can sterilely protect swine challenged with foot-and-mouth disease virus (FMDV) 1 day later. However, the need of relatively high doses of Ad5 limits the applicability of such a control strategy in the livestock industry. Venezuelan equine encephalitis virus (VEE) empty replicon particles (VRPs) can induce rapid protection of mice against either homologous or, in some cases, heterologous virus challenge. As an alternative approach to induce rapid protection against FMDV, we have examined the ability of VRPs containing either the gene for green fluorescent protein (VRP-GFP) or poIFN-α (VRP-poIFN-α) to block FMDV replication in vitro and in vivo. Pretreatment of swine or bovine cell lines with either VRP significantly inhibited subsequent infection with FMDV as early as 6 h after treatment and for at least 120 h posttreatment. Furthermore, mice pretreated with either 107 or 108 infectious units of VRP-GFP and challenged with a lethal dose of FMDV 24 h later were protected from death. Protection was induced as early as 6 h after treatment and lasted for at least 48 h and correlated with induction of an antiviral response and production of IFN-α. By 6 h after treatment several genes were upregulated, and the number of genes and the level of induction increased at 24 h. Finally, we demonstrated that the chemokine IP-10, which is induced by IFN-α and VRP-GFP, is directly involved in protection against FMDV. PMID:23468490

  9. Gas-to-particle conversion in the atmospheric environment by radiation-induced and photochemical reactions

    International Nuclear Information System (INIS)

    Vohra, K.G.

    1975-01-01

    During the last few years a fascinating new area of research involving ionizing radiations and photochemistry in gas-to-particle conversion in the atmosphere has been developing at a rapid pace. Two problems of major interest and concern in which this is of paramount importance are: (1) radiation induced and photochemical aerosol formation in the stratosphere and, (2) role of radiations and photochemistry in smog formation. The peak in cosmic ray intensity and significant solar UV flux in the stratosphere lead to complex variety of reactions involving major and trace constituents in this region of the atmosphere, and some of these reactions are of vital importance in aerosol formation. The problem is of great current interest because the pollutant gases from industrial sources and future SST operations entering the stratosphere could increase the aerosol burden in the stratosphere and affect the solar energy input of the troposphere with consequent ecological and climatic changes. On the other hand, in the nuclear era, the atmospheric releases from reactors and processing plants could lead to changes in the cloud nucleation behaviour of the environment and possible increase in smog formation in the areas with significant levels of radiations and conventional pollutants. A review of the earlier work, current status of the problem, and conventional pollutants. A review of the earlier work, current status of the problem, and some recent results of the experiments conducted in the author's laboratory are presented. The possible mechanisms of gas-to-particle conversion in the atmosphere have been explained

  10. Spatial learning and memory deficits induced by exposure to iron-56-particle radiation

    Science.gov (United States)

    Shukitt-Hale, B.; Casadesus, G.; McEwen, J. J.; Rabin, B. M.; Joseph, J. A.

    2000-01-01

    It has previously been shown that exposing rats to particles of high energy and charge (HZE) disrupts the functioning of the dopaminergic system and behaviors mediated by this system, such as motor performance and an amphetamine-induced conditioned taste aversion; these adverse behavioral and neuronal effects are similar to those seen in aged animals. Because cognition declines with age, spatial learning and memory were assessed in the Morris water maze 1 month after whole-body irradiation with 1.5 Gy of 1 GeV/nucleon high-energy (56)Fe particles, to test the cognitive behavioral consequences of radiation exposure. Irradiated rats demonstrated cognitive impairment compared to the control group as seen in their increased latencies to find the hidden platform, particularly on the reversal day when the platform was moved to the opposite quadrant. Also, the irradiated group used nonspatial strategies during the probe trials (swim with no platform), i.e. less time spent in the platform quadrant, fewer crossings of and less time spent in the previous platform location, and longer latencies to the previous platform location. These findings are similar to those seen in aged rats, suggesting that an increased release of reactive oxygen species may be responsible for the induction of radiation- and age-related cognitive deficits. If these decrements in behavior also occur in humans, they may impair the ability of astronauts to perform critical tasks during long-term space travel beyond the magnetosphere.

  11. Comparison of fluorescence-based techniques for the quantification of particle-induced hydroxyl radicals

    Directory of Open Access Journals (Sweden)

    Cohn Corey A

    2008-02-01

    Full Text Available Abstract Background Reactive oxygen species including hydroxyl radicals can cause oxidative stress and mutations. Inhaled particulate matter can trigger formation of hydroxyl radicals, which have been implicated as one of the causes of particulate-induced lung disease. The extreme reactivity of hydroxyl radicals presents challenges to their detection and quantification. Here, three fluorescein derivatives [aminophenyl fluorescamine (APF, amplex ultrared, and dichlorofluorescein (DCFH] and two radical species, proxyl fluorescamine and tempo-9-ac have been compared for their usefulness to measure hydroxyl radicals generated in two different systems: a solution containing ferrous iron and a suspension of pyrite particles. Results APF, amplex ultrared, and DCFH react similarly to the presence of hydroxyl radicals. Proxyl fluorescamine and tempo-9-ac do not react with hydroxyl radicals directly, which reduces their sensitivity. Since both DCFH and amplex ultrared will react with reactive oxygen species other than hydroxyl radicals and another highly reactive species, peroxynitite, they lack specificity. Conclusion The most useful probe evaluated here for hydroxyl radicals formed from cell-free particle suspensions is APF due to its sensitivity and selectivity.

  12. Applications of particle induced X-ray emission analysis to ambient aerosol studies

    International Nuclear Information System (INIS)

    Lannefors, H.

    1982-01-01

    The characteristics of Particle Induced X-ray Emission (PIXE) analysis in conjunction with different ambient aerosol samplers have been studied. Correction factors have been calculated for homogeneous and inhomogeneous rural and urban aerosol samples. The Nuclepore two stage filter sampler provided the most useful combination of the resolution and particle size fractionation in urban, rural and remote environments. The PIXE-analysis technique in combination with different samplers was employed in aerosol composition studies in rural and remote environments. Particular emphasis was laid on studies of aerosol long range transport. Based on air mass trajectory analysis and aerosol composition measurements the foreign contribution in southern Sweden was estimated to be 70 - 80% for S and Pb but only 30 - 50% for V and Ni. The spatial and temporal extension of a long range transport episode was studied using high time resolution continuous filter samplers in a network in southern Sweden. The variation in the concentration levels of sulphur agreed well with changes in the air mass history. Arctic summer elemental concentration levels as measured during the Swedish YMER-80 icebreaker expedition were typically one order of magnitude lower than Arctic winter levels. The combination of chemical information, optical properties and size distribution data supports the hypothesis of long range transport of air pollution into the Arctic especially during the winter. This takes place during the winter season because the Polar front is further south making conditions for long range transport up to the Arctic more favourable. (Auth.)

  13. Particle Size-Dependent Antibacterial Activity and Murine Cell Cytotoxicity Induced by Graphene Oxide Nanomaterials

    Directory of Open Access Journals (Sweden)

    Lin Zhao

    2016-01-01

    Full Text Available Recent studies have indicated that graphene and its derivative graphene oxide (GO engage in a wide range of antibacterial activities with limited toxicity to human cells. Here, we systematically evaluate the dependence of GO toxicity on the size of the nanoparticles used in treatments: we compare the cytotoxic effects of graphene quantum dots (GQDs, <15 nm, small GOs (SGOs, 50–200 nm, and large GOs (LGOs, 0.5–3 μm. We synthesize the results of bacterial colony count assays and SEM-based observations of morphological changes to assess the antibacterial properties that these GOs bring into effect against E. coli. We also use Live/Dead assays and morphological analysis to investigate changes to mammalian (Murine macrophage-like Raw 264.7 cells induced by the presence of the various GO particle types. Our results demonstrate that LGOs, SGOs, and GQDs possess antibacterial activities and cause mammalian cell cytotoxicity at descending levels of potency. Placing our observations in the context of previous simulation results, we suggest that both the lateral size and surface area of GO particles contribute to cytotoxic effects. We hope that the size dependence elucidated here provides a useful schematic for tuning GO-cell interactions in biomedical applications.

  14. Charges collection induced in APS by heavy particles: influence of design parameters

    International Nuclear Information System (INIS)

    Belredon, Xavier

    2003-01-01

    We have studied the design parameters influence on heavy ions-induced charge collection physics in APS. The goal is to determine the key parameters for an optimised space environment 'particle detector' APS design. It appears that diffusion is the dominant charge collection mechanism in all the studied technology types, with a smaller magnitude in case of epitaxial technologies. Following proton irradiation, a delayed charge collection and loss of collected charges have been observed. These phenomena are explained by the combination of carriers diffusion and action of the traps generated in the device. Even if they cannot be avoid in space applications, these effects are reduced in case of epitaxial technologies. This work led to the design parameters definition of an optimized APS 'particle detector' and to its fabrication. The results obtained on this APS confirm the previous conclusions and let us define the detection range of such detectors from 0.03 to 50 MeV.cm 2 .mg -1 . (author) [fr

  15. Bystander-induced apoptosis and premature differentiation in primary urothelial explants after charged particle microbeam irradiation

    International Nuclear Information System (INIS)

    Belyakov, O.V.; Folkard, M.; Mothersill, C.; Prise, K.M.; Michael, B.D.

    2002-01-01

    The ureter primary explant technique was developed to study bystander effects under in vivo like conditions where stem and differentiated cells are present. Irradiation was performed with a 3 He 2+ charged particle microbeam available at the Gray Cancer Institute, with high (∼2 μm) precision. Tissue sections from porcine ureters were pre-irradiated with the microbeam at a single location with 10 3 He 2+ particles (5 MeV; LET 70 keV.μm -1 ). After irradiation, the tissue section was incubated for 7 days, thus allowing the explant outgrowth to form. Total cellular damage (total fraction of micronucleated and apoptotic cells) was measured according to morphological criteria. Apoptosis was also assessed using a 3'-OH DNA end-labelling technique. Premature differentiation was estimated using antibodies to uroplakin III, a specific marker of terminal urothelial differentiation. Results of our experiments demonstrated a significant bystander-induced differentiation and a less significant increase in apoptotic and micronucleated cells. A hypothesis based on the protective nature of the bystander effect is proposed. (author)

  16. Review of Heavy-ion Induced Desorption Studies for Particle Accelerators

    CERN Document Server

    Mahner, E

    2008-01-01

    During high-intensity heavy-ion operation of several particle accelerators worldwide, large dynamic pressure rises of orders of magnitude were caused by lost beam ions that impacted under grazing angle onto the vacuum chamber walls. This ion-induced desorption, observed, for example, at CERN, GSI, and BNL, can seriously limit the ion intensity, luminosity, and beam lifetime of the accelerator. For the heavyion program at CERN's Large Hadron Collider collisions between beams of fully stripped lead (208Pb82+) ions with a beam energy of 2.76 TeV/u and a nominal luminosity of 10**27 cm**-2 s**-1 are foreseen. The GSI future project FAIR (Facility for Antiproton and Ion Research) aims at a beam intensity of 10**12 uranium (238U28+) ions per second to be extracted from the synchrotron SIS18. Over the past years an experimental effort has been made to study the observed dynamic vacuum degradations, which are important to understand and overcome for present and future particle accelerators. The paper reviews the resu...

  17. Titanium dioxide particleinduced goblet cell hyperplasia : association with mast cells and IL-13

    Directory of Open Access Journals (Sweden)

    Kim Soo-Ho

    2005-04-01

    Full Text Available Abstract Background Inhalation of particles aggravates respiratory symptoms including mucus hypersecretion in patients with chronic airway disease and induces goblet cell hyperplasia (GCH in experimental animal models. However, the underlying mechanisms remain poorly understood. Methods To understand this, the numbers of goblet cells, Muc5ac (+ expressing epithelial cells and IL-13 expressing mast cells were measured in the trachea of sham or TiO2 particles – treated rats using periodic acid-Schiff, toluidine blue and immunohistochemical staining. RT-PCR for Muc-1, 2 and 5ac gene transcripts was done using RNA extracted from the trachea. Differential cell count and IL-13 levels were measured in bronchoalveolar lavage (BAL fluid. In pretreatment groups, cyclophosphamide (CPA or dexamethasone (DEX was given before instillation of TiO2. TiO2 treatment markedly increased Muc5ac mRNA expression, and Muc5ac (+ or PAS (+ epithelial cells 48 h following treatment. Results The concentration of IL-13 in BAL fluids was higher in TiO2 treated – rats when compared to those in sham rats (p 2 treated – rats (p 0.05. In contrast, pretreatment with dexamethasone (DEX diminished the percentage of PAS (+ cells and the levels of IL-13 (p 2 treatment increased the IL-13 (+ mast cells (p 0.05. In addition there were significant correlations of IL-13 (+ rate of mast cells in the trachea with IL-13 concentration in BAL fluid (p 2 treated rats (p Conclusion In conclusion, TiO2 instillation induces GCH and Muc5ac expression, and this process may be associated with increased production of IL-13 by mast cells.

  18. Interfacial effect on physical properties of composite media: Interfacial volume fraction with non-spherical hard-core-soft-shell-structured particles.

    Science.gov (United States)

    Xu, Wenxiang; Duan, Qinglin; Ma, Huaifa; Chen, Wen; Chen, Huisu

    2015-11-02

    Interfaces are known to be crucial in a variety of fields and the interfacial volume fraction dramatically affects physical properties of composite media. However, it is an open problem with great significance how to determine the interfacial property in composite media with inclusions of complex geometry. By the stereological theory and the nearest-surface distribution functions, we first propose a theoretical framework to symmetrically present the interfacial volume fraction. In order to verify the interesting generalization, we simulate three-phase composite media by employing hard-core-soft-shell structures composed of hard mono-/polydisperse non-spherical particles, soft interfaces, and matrix. We numerically derive the interfacial volume fraction by a Monte Carlo integration scheme. With the theoretical and numerical results, we find that the interfacial volume fraction is strongly dependent on the so-called geometric size factor and sphericity characterizing the geometric shape in spite of anisotropic particle types. As a significant interfacial property, the present theoretical contribution can be further drawn into predicting the effective transport properties of composite materials.

  19. MIL-125-NH2@TiO2 Core-Shell Particles Produced by a Post-Solvothermal Route for High-Performance Photocatalytic H2 Production.

    Science.gov (United States)

    Zhang, Bingxing; Zhang, Jianling; Tan, Xiuniang; Shao, Dan; Shi, Jinbiao; Zheng, Lirong; Zhang, Jing; Yang, Guanying; Han, Buxing

    2018-05-02

    Metal-organic frameworks (MOFs) have proven to be an interesting class of sacrificial precursors of functional inorganic materials for catalysis, energy storage, and conversion applications. However, the controlled synthesis of MOF-derived materials with desirable compositions, structures, and properties still remains a big challenge. Herein, we propose a post-solvothermal route for the outer-to-inner loss of organic linkers from MOF, which is simple, rapid, and controllable and can be operated at temperature much lower than that of the commonly adopted pyrolysis method. By such a strategy, the MIL-125-NH 2 particles coated by TiO 2 nanosheets were produced, and the thickness of TiO 2 shell can be easily tuned. The MIL-125-NH 2 @TiO 2 core-shell particles combine the advantages of highly active TiO 2 nanosheets, MIL-125-NH 2 photosensitizer, plenty of linker defects and oxygen vacancies, and mesoporous structure, which allows them to be utilized as photocatalysts for the visible-light-driven hydrogen production reaction. It is remarkable that the hydrogen evolution rate by MIL-125-NH 2 @TiO 2 can be enhanced 70 times compared with the pristine MIL-125-NH 2 . Such a route can be easily applied to the synthesis of different kinds of MOF-derived functional materials.

  20. Core hydrophobicity tuning of a self-assembled particle results in efficient lipid reduction and favorable organ distribution.

    Science.gov (United States)

    Banik, Bhabatosh; Wen, Ru; Marrache, Sean; Kumar, Anil; Kolishetti, Nagesh; Howerth, Elizabeth W; Dhar, Shanta

    2017-12-21

    Atherosclerosis, the deadliest disease in the United States, arises due to the build up of plaques in the arteries as a result of excessive cholesterol deposition and an impaired cholesterol removal process. High density lipoproteins (HDL), popularly known as "good cholesterol", are naturally occurring nano-sized particles that, along with apolipoproteins, are deployed to maintain cholesterol homeostasis in the body. Both cholesterol efflux, from the fat-laden macrophages in the arteries, and intracellular lipid transport, to deliver cholesterol to the mitochondria of liver cells for metabolism, hold key responsibilities to maintain healthy lipid levels inside the body. We designed a library of nine mitochondria targeted polymer-lipid hybrid nanoparticles (NPs), comprised of completely synthetic yet biodegradable components, that are capable of performing HDL-like functions. Using this library, we optimized a superior mitochondria targeted NP candidate, which can show favourable organ distribution, therapeutic potential, and non-toxic properties. Two targeted NP formulations with optimum NP size, zeta potential, and cholesterol binding and release properties were identified. Lipid reduction and anti-oxidative properties of these two NPs demonstrated cholesterol removal ability. In vivo therapeutic evaluation of the targeted-NP formulations in apolipoprotein E knockout (apoE - / - ) mice indicated lipid reduction and anti-inflammatory properties compared to non-targeted NPs. This synthetic targeted NP with potential abilities to participate in both extra- and intracellular cholesterol transport might potentiate therapeutic interventions for heart diseases.

  1. Just-in-time vaccines: Biomineralized calcium phosphate core-immunogen shell nanoparticles induce long-lasting CD8(+) T cell responses in mice.

    Science.gov (United States)

    Zhou, Weibin; Moguche, Albanus O; Chiu, David; Murali-Krishna, Kaja; Baneyx, François

    2014-04-01

    Distributed and on-demand vaccine production could be game-changing for infectious disease treatment in the developing world by providing new therapeutic opportunities and breaking the refrigeration "cold chain". Here, we show that a fusion protein between a calcium phosphate binding domain and the model antigen ovalbumin can mineralize a biocompatible adjuvant in a single step. The resulting 50 nm calcium phosphate core-immunogen shell particles are comparable to soluble protein in inducing ovalbumin-specific antibody response and class switch recombination in mice. However, single dose vaccination with nanoparticles leads to higher expansion of ovalbumin-specific CD8(+) T cells upon challenge with an influenza virus bearing the ovalbumin-derived SIINFEKL peptide, and these cells produce high levels of IFN-γ. Furthermore, mice exhibit a robust antigen-specific CD8(+) T cell recall response when challenged with virus 8 months post-immunization. These results underscore the promise of immunogen-controlled adjuvant mineralization for just-in-time manufacturing of effective T cell vaccines. This paper reports that a fusion protein between a calcium phosphate binding domain and the model antigen ovalbumin can mineralize into a biocompatible adjuvant in a single step, enabling distributed and on-demand vaccine production and eliminating the need for refrigeration of vaccines. The findings highlight the possibility of immunogen-controlled adjuvant mineralization for just-in-time manufacturing of effective T cell vaccines. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Just-in-time vaccines: Biomineralized calcium phosphate core-immunogen shell nanoparticles induce long-lasting CD8+ T cell responses in mice

    Science.gov (United States)

    Zhou, Weibin; Moguche, Albanus; Chiu, David; Murali-Krishna, Kaja; Baneyx, François

    2014-01-01

    Distributed and on-demand vaccine production could be game-changing for infectious disease treatment in the developing world by providing new therapeutic opportunities and breaking the refrigeration “cold chain”. Here, we show that a fusion protein between a calcium phosphate binding domain and the model antigen ovalbumin can mineralize a biocompatible adjuvant in a single step. The resulting 50 nm calcium phosphate core-immunogen shell particles are comparable to soluble protein in inducing ovalbumin-specific antibody response and class switch recombination in mice. However, single dose vaccination with nanoparticles leads to higher expansion of ovalbumin-specific CD8+ T cells upon challenge with an influenza virus bearing the ovalbumin-derived SIINFEKL peptide, and these cells produce high levels of IFN-γ. Furthermore, mice exhibit a robust antigen-specific CD8+ T cell recall response when challenged with virus 8 months post-immunization. These results underscore the promise of immunogen-controlled adjuvant mineralization for just-in-time manufacturing of effective T cell vaccines. PMID:24275478

  3. Effect of free-particle collisions in high energy proton and pion-induced nuclear reactions

    International Nuclear Information System (INIS)

    Jacob, N.P. Jr.

    1975-07-01

    The effect of free-particle collisions in simple ''knockout'' reactions of the form (a,aN) and in more complex nuclear reactions of the form (a,X) was investigated by using protons and pions. Cross sections for the 48 Ti(p,2p) 47 Sc and the 74 Ge(p,2p) 73 Ga reactions were measured from 0.3 to 4.6 GeV incident energy. The results indicate a rise in (p,2p) cross section for each reaction of about (25 +- 3) percent between the energies 0.3 and 1.0 GeV, and are correlated to a large increase in the total free-particle pp scattering cross sections over the same energy region. Results are compared to previous (p,2p) excitation functions in the GeV energy region and to (p,2p) cross section calculations based on a Monte Carlo intranuclear cascade-evaporation model. Cross section measurements for (π/sup +-/, πN) and other more complex pion-induced spallation reactions were measured for the light target nuclei 14 N, 16 O, and 19 F from 45 to 550 MeV incident pion energy. These measurements indicate a broad peak in the excitation functions for both (π,πN) and (π,X) reactions near 180 MeV incident energy. This corresponds to the large resonances observed in the free-particle π + p and π - p cross sections at the same energy. Striking differences in (π,πN) cross section magnitudes are observed among the light nuclei targets. The experimental cross section ratio sigma(π - ,π - n)/sigma(π + ,πN) at 180 MeV is 1.7 +- 0.2 for all three targets. The experimental results are compared to previous pion and analogous proton-induced reactions, to Monte Carlo intranuclear cascade-evaporation calculations, and to a semi-classical nucleon charge exchange model. (108 references) (auth)

  4. Unhealthy diet and ultrafine carbon black particles induce senescence and disease associated phenotypic changes.

    Science.gov (United States)

    Büchner, Nicole; Ale-Agha, Niloofar; Jakob, Sascha; Sydlik, Ulrich; Kunze, Kerstin; Unfried, Klaus; Altschmied, Joachim; Haendeler, Judith

    2013-01-01

    Diet and pollution are environmental factors known to compromise "healthy aging" of the cardiovascular and respiratory systems. The molecular consequences of this permanent burden in these cells are still unknown. Therefore, this study investigates the impact of unhealthy diet on aging-related signaling pathways of human, primary cardiovascular cells and of airborne particles on lung epithelial and human endothelial cells. Nutrition health reports have shown that the diet in industrialized countries contains more than 100mg/dl low density lipoprotein (LDL) and a high fraction of added sugars, especially fructose. Several studies demonstrated that ultrafine particles can enter the circulation and thus may interact with endothelial cells directly. Both, dietary compounds and pollution derived particles, have been shown to increase the risk for cardiovascular diseases. To simulate an unhealthy diet, we supplemented cell culture media of human primary endothelial cells, smooth muscle cells and cardiomyocytes with LDL and replaced 1/3 of glucose with fructose. We observed hypertrophy in cardiomyocytes, enhanced proliferation in smooth muscle cells and increased senescence, loss of endothelial nitric oxide synthase and increased nuclear FoxO3A in endothelial cells. With respect to pollution we have used ultrafine carbon black particles (ufCB), one of the major constituents of industrial and exhaust emissions, in concentrations our lungs and vessels are constantly exposed to. These concentrations of ufCB increased reactive oxygen species in lung epithelial and vascular endothelial cells and reduced the S-NO content, a marker for NO-bioavailability, in endothelial cells. NO increases activation of Telomerase Reverse Transcriptase (TERT), an enzyme essential for telomere maintenance. TERT is required for proper endothelial cell function and is inactivated by Src kinase under conditions of oxidative stress. ufCB significantly increased Src kinase activation and reduced

  5. First measurements on the core and edge isotope composition using the JET isotope separator neutral particle analyser

    International Nuclear Information System (INIS)

    Bettella, D; Murari, A; Stamp, M; Testa, D

    2003-01-01

    Direct measurements of tokamak plasmas isotope composition are in general quite difficult and have therefore been very seldom performed. On the other hand, the importance of this measurement is going to increase, as future experiments will be progressively focused on plasmas approaching reactor conditions. In this paper, we report for the first time encouraging experimental evidence supporting a new method to determine the radial profile of the density ratio n H /(n H + n D ), based on neutral particle analyser (NPA) measurements. The measurements have been performed in JET with the ISotope SEParator (ISEP), a NPA device specifically developed to measure the energy spectra of the three hydrogen isotopes with very high accuracy and low cross-talk. The data presented here have been collected in two different experimental conditions. In the first case, the density ratio has been kept constant during the discharge. The isotope ratio derived from the ISEP has been compared with the results of visible spectroscopy at the edge and with the isotope composition derived from an Alfven eigenmodes active diagnostic (AEAD) system at about half the minor radius for the discharges reported in this paper. A preliminary evaluation of the additional heating effects on the measurements has also been carried out. In the second set of experiments, the isotope composition of deuterium plasmas has been abruptly changed with suitable short blips of hydrogen, in order to assess the capability of the method to study the transport of the hydrogen isotope species. Future developments of the methodology and its applications to the evaluation of hydrogen transport coefficients are also briefly discussed. The results obtained so far motivate further development of the technique, which constitutes one of the few candidate diagnostic approaches viable for ITER

  6. DCHAIN-SP 2001: High energy particle induced radioactivity calculation code

    Energy Technology Data Exchange (ETDEWEB)

    Kai, Tetsuya; Maekawa, Fujio; Kasugai, Yoshimi; Takada, Hiroshi; Ikeda, Yujiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kosako, Kazuaki [Sumitomo Atomic Energy Industries, Ltd., Tokyo (Japan)

    2001-03-01

    For the purpose of contribution to safety design calculations for induced radioactivities in the JAERI/KEK high-intensity proton accelerator project facilities, the DCHAIN-SP which calculates the high energy particle induced radioactivity has been updated to DCHAIN-SP 2001. The following three items were improved: (1) Fission yield data are included to apply the code to experimental facility design for nuclear transmutation of long-lived radioactive waste where fissionable materials are treated. (2) Activation cross section data below 20 MeV are revised. In particular, attentions are paid to cross section data of materials which have close relation to the facilities, i.e., mercury, lead and bismuth, and to tritium production cross sections which are important in terms of safety of the facilities. (3) User-interface for input/output data is sophisticated to perform calculations more efficiently than that in the previous version. Information needed for use of the code is attached in Appendices; the DCHAIN-SP 2001 manual, the procedures of installation and execution of DCHAIN-SP, and sample problems. (author)

  7. Rate laws of the self-induced aggregation kinetics of Brownian particles

    Science.gov (United States)

    Mondal, Shrabani; Sen, Monoj Kumar; Baura, Alendu; Bag, Bidhan Chandra

    2016-03-01

    In this paper we have studied the self induced aggregation kinetics of Brownian particles in the presence of both multiplicative and additive noises. In addition to the drift due to the self aggregation process, the environment may induce a drift term in the presence of a multiplicative noise. Then there would be an interplay between the two drift terms. It may account qualitatively the appearance of the different laws of aggregation process. At low strength of white multiplicative noise, the cluster number decreases as a Gaussian function of time. If the noise strength becomes appreciably large then the variation of cluster number with time is fitted well by the mono exponentially decaying function of time. For additive noise driven case, the decrease of cluster number can be described by the power law. But in case of multiplicative colored driven process, cluster number decays multi exponentially. However, we have explored how the rate constant (in the mono exponentially cluster number decaying case) depends on strength of interference of the noises and their intensity. We have also explored how the structure factor at long time depends on the strength of the cross correlation (CC) between the additive and the multiplicative noises.

  8. Measurements on rotating ion cyclotron range of frequencies induced particle fluxes in axisymmetric mirror plasmas

    International Nuclear Information System (INIS)

    Hatakeyama, R.; Hershkowitz, N.; Majeski, R.; Wen, Y.J.; Brouchous, D.B.; Proberts, P.; Breun, R.A.; Roberts, D.; Vukovic, M.; Tanaka, T.

    1997-01-01

    A comparison of phenomenological features of plasmas is made with a special emphasis on radio-frequency induced transport, which are maintained when a set of two closely spaced dual half-turn antennas in a central cell of the Phaedrus-B axisymmetric tandem mirror [J. J. Browning et al., Phys. Fluids B 1, 1692 (1989)] is phased to excite electromagnetic fields in the ion cyclotron range of frequencies (ICRF) with m=-1 (rotating with ions) and m=+1 (rotating with electrons) azimuthal modes. Positive and negative electric currents are measured to flow axially to the end walls in the cases of m=-1 and m=+1 excitations, respectively. These parallel nonambipolar ion and electron fluxes are observed to be accompanied by azimuthal ion flows in the same directions as the antenna-excitation modes m. The phenomena are argued in terms of radial particle fluxes due to a nonambipolar transport mechanism [Hojo and Hatori, J. Phys. Soc. Jpn. 60, 2510 (1991); Hatakeyama et al., J. Phys. Soc. Jpn. 60, 2815 (1991), and Phys. Rev. E 52, 6664 (1995)], which are induced when azimuthally traveling ICRF waves are absorbed in the magnetized plasma column. copyright 1997 American Institute of Physics

  9. Vaccination with dengue virus-like particles induces humoral and cellular immune responses in mice

    Directory of Open Access Journals (Sweden)

    Zhang Quanfu

    2011-06-01

    Full Text Available Abstract Background The incidence of dengue, an infectious disease caused by dengue virus (DENV, has dramatically increased around the world in recent decades and is becoming a severe public health threat. However, there is currently no specific treatment for dengue fever, and licensed vaccine against dengue is not available. Vaccination with virus-like particles (VLPs has shown considerable promise for many viral diseases, but the effect of DENV VLPs to induce specific immune responses has not been adequately investigated. Results By optimizing the expression plasmids, recombinant VLPs of four antigenically different DENV serotypes DENV1-4 were successfully produced in 293T cells. The vaccination effect of dengue VLPs in mice showed that monovalent VLPs of each serotype stimulated specific IgG responses and potent neutralizing antibodies against homotypic virus. Tetravalent VLPs efficiently enhanced specific IgG and neutralizing antibodies against all four serotypes of DENV. Moreover, vaccination with monovalent or tetravalent VLPs resulted in the induction of specific cytotoxic T cell responses. Conclusions Mammalian cell expressed dengue VLPs are capable to induce VLP-specific humoral and cellular immune responses in mice, and being a promising subunit vaccine candidate for prevention of dengue virus infection.

  10. Determination of antibodies for the core antigen of the hepatitis B virus by means of a direct radioimmunoassay with /sup 32/P-marked core particles. Nachweis von Antikoerpern gegen das Core Antigen des Hepatitis B Virus durch einen direkten Radioimmunoassay mit /sup 32/P markierten Core Partikeln

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, W

    1983-11-04

    After characterization of the protein kinase of the hepatitus B virus and the purification of this enzyme, the enzyme was proved to be a component of the core particle with a high affinity for ATP. Based on this a new procedure for the determination of the diagnostically important antibody for HBcAg (anti HBc) is presented, namely the direct radioimmunoassay by means of the marking of HBcAg with /sup 32/P. This procedure is much more sensitive than the traditional inhibitory test using an enzyme-marked anti-HBc immunoglobulin as a reagent (EIBA). Using this new RIA anti-HBc was shown to be present in the majority of the EIBA anti-HBc positive serums and also in a large number of EIBA anti-HBc negative serums from a population at high risk for the Hepatitis B virus. The significance of reproducible threshold values was also shown. RIA activity was seldom found in healthy blood donors without HBsAg and anti-HBs. On the other hand blood donors with increased serum transaminase values showed a significantly higher frequency of activity. This weak activity only determinable in dRIA, could be attributed to a very limited heaptitis B viral infection or to a cross-reaction. (TRV)

  11. Impact on Divertor Operation of the Pattern of Edge and SOL Flows Induced by Particle Sources and Sinks

    Energy Technology Data Exchange (ETDEWEB)

    Ghendrih, P.; Bucalossi, J.; Futtersack, R.; Guillemaut, C.; Moulton, D.; Tamain, P., E-mail: philippe.ghendrih@cea.fr [CEA-IRFM, Saint Paul-lez-Durance (France); Auphan, T.; Mentrelli, A. [LATP, Technopole de Chateau-Gombert, Marseille (France); Bensiali, B.; Chiavassa, G.; Ciracolo, G.; Paredes, A.; Serre, E.; Schwander, F. [M2P2, Technopole de Chateau-Gombert, Marseille (France); Bilanceri, M.; Guillard, H. [INRIA, Sophia Antipolis and LJAD, Nice (France); Bodi, K. [M2P2, Technopole de Chateau-Gombert, Marseille (France); Dept. of Aerospace Engg., IIT Bombay, Mumbai (India); Bufferand, H. [CEA-IRFM, Saint Paul-lez-Durance (France); M2P2,Technopole de Chateau-Gombert, Marseille (France); Marandet, Y. [PIIM, CNRS/Aix-Marseille Universite, Marseille (France); Pasquetti, R. [LJAD, Nice (France)

    2012-09-15

    Full text: The role of divertors in present device operation is to control particle sources and sinks and consequently the energy flux channels in the boundary region of magnetically confined plasmas. The ESPOIR effort is based on a set of fluid codes from 1-D parallel to 3-D micro-turbulence modelling. Due to the long range particle transport into the SOL governed by intermittent turbulent bursts, the precise location of the particle sources at the wall is required to properly address the screening of the neutral particle influx. To that end we have developed a penalisation technique that extends the simulation domain up to all the plasma facing components of interest. The penalisation technique initiated for particle and momentum sinks has been extended to the temperatures as well as to electric currents. We have used the penalisation technique in 2D simulations of the radial shift of the plasma from the low field side modular limiter to the high field side bumper limiter. Experiments of the kind where achieved in TFTR, JET and Tore Supra to investigate the particle confinement time and particle trapping in the wall. We show that the ballooned transport plays a crucial role in these experiments so that most of the core density drop is reversible. In the divertor configuration, low ionisation sources are shown to govern a supersonic solution. Simulations of such a regime exhibit weak divertor density variation as the core plasma density is ramped up, in agreement with analytical predictions. In the standard divertor regimes, we show analytically that the plasma tends to a supersonic flow when the total plasma pressure is conserved along the field lines. The back transition to the subsonic flow at the plate then takes place at the cross-over between the diffusive heat transport and the convective energy transport. Such behaviour disappears when total plasma pressure losses take place. In the case of very strong divertor screening one finds a Mach number close to

  12. Core-hole-induced dynamical effects in the x-ray emission spectrum of liquid methanol.

    Science.gov (United States)

    Ljungberg, M P; Zhovtobriukh, I; Takahashi, O; Pettersson, L G M

    2017-04-07

    We compute the x-ray emission spectrum of liquid methanol, with the dynamical effects that result from the creation of the core hole included in a semiclassical way. Our method closely reproduces a fully quantum mechanical description of the dynamical effects for relevant one-dimensional models of the hydrogen-bonded methanol molecules. For the liquid, we find excellent agreement with the experimental spectrum, including the large isotope effect in the first split peak. The dynamical effects depend sensitively on the initial structure in terms of the local hydrogen-bonding (H-bonding) character: non-donor molecules contribute mainly to the high-energy peak while molecules with a strong donating H-bond contribute to the peak at lower energy. The spectrum thus reflects the initial structure mediated by the dynamical effects that are, however, seen to be crucial in order to reproduce the intensity distribution of the recently measured spectrum.

  13. Dynamics of magnetic particles near a surface : model and experiments on field-induced disaggregation

    NARCIS (Netherlands)

    van Reenen, A.; Gao, Y.; de Jong, Arthur; Hulsen, M.A.; den Toonder, J.M.J.; Prins, M.W.J.

    2014-01-01

    Magnetic particles are widely used in biological research and bioanalytical applications. As the corresponding tools are progressively being miniaturized and integrated, the understanding of particle dynamics and the control of particles down to the level of single particles become important. Here,

  14. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    International Nuclear Information System (INIS)

    Wong, T.P.W.; Tse, A.K.W.; Fong, W.F.; Yu, K.N.

    2009-01-01

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  15. Studying effects of Magnolol on alpha-particle induced bystander effects using PADC-film based dishes

    Energy Technology Data Exchange (ETDEWEB)

    Wong, T.P.W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Tse, A.K.W.; Fong, W.F. [Research and Development Division, School of Chinese Medicine, Hong Kong Baptist University, Baptist University Road, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    Radiation-induced bystander effect refers to the biological response found in cells (called bystander cells) which are not irradiated directly by ionizing radiation but are next to cells irradiated directly by ionizing radiation. In the present paper, the effects of Magnolol, an extract from the bark of Magnolia officinalis which is used as a traditional Chinese medicine, were studied on alpha-particle induced bystander effects. In our experiments, Chinese hamster ovary (CHO) cells were cultured in PADC-film based dishes and were irradiated with low fluences of alpha particles passing through the PADC films. The precise number of cells traversed or missed by alpha particles could be determined by studying the alpha-particle tracks developed on the PADC films upon subsequent chemical etching. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to analyze the biological response of bystander cells in terms of DNA strand breaks. With the pretreatment of Magnolol, the DNA strand breaks in bystander cells were reduced, which showed that the alpha-particle induced bystander effects were suppressed with the presence of Magnolol. Since Magnolol is an antioxidant which can scavenge reactive oxygen species (ROS), our results give support to that ROS play a role in the bystander signal transmission in our experiments.

  16. Alpha Particles and X Rays Interact in Inducing DNA Damage in U2OS Cells.

    Science.gov (United States)

    Sollazzo, Alice; Brzozowska, Beata; Cheng, Lei; Lundholm, Lovisa; Haghdoost, Siamak; Scherthan, Harry; Wojcik, Andrzej

    2017-10-01

    Survivors of the atomic bombings of Hiroshima and Nagasaki are monitored for health effects within the Life Span Study (LSS). The LSS results represent the most important source of data about cancer effects from ionizing radiation exposure, which forms the foundation for the radiation protection system. One uncertainty connected to deriving universal risk factors from these results is related to the problem of mixed radiation qualities. The A-bomb explosions generated a mixed beam of the sparsely ionizing gamma radiation and densely ionizing neutrons. However, until now the possible interaction of the two radiation types of inducing biological effects has not been taken into consideration. The existence of such interaction would suggest that the application of risk factors derived from the LSS to predict cancer effects after pure gamma-ray irradiation (such as in the Fukushima prefecture) leads to an overestimation of risk. To analyze the possible interaction of radiation types, a mixed-beam exposure facility was constructed where cells can be exposed to sparsely ionizing X rays and densely ionizing alpha particles. U2OS cells were used, which are stably transfected with a plasmid coding for the DNA repair gene 53BP1 coupled to a gene coding for the green fluorescent protein (GFP). The induction and repair of DNA damage, which are known to be related to cancer induction, were analyzed. The results suggest that alpha particles and X rays interact, leading to cellular and possibly cancer effects, which cannot be accurately predicted based on assuming simple additivity of the individual mixed-beam components.

  17. Thresholds and Q values of nuclear reactions induced by neutrons, protons, deuterons, tritons, 3He ions, alpha particles, and photons

    International Nuclear Information System (INIS)

    Howerton, R.J.

    1981-01-01

    The 1977 Wapstra and Bos nuclear mass data tables were used to derive tables for thresholds and Q values of nuclear reactions induced by neutrons, protons, deuterons, tritons, 3 He ions, alpha particles, and photons. The tables are displayed on microfiche included with the report

  18. Charged particle spectra in oxygen-induced reactions at 14. 6 and 60 GeV/Nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Adamovich, M I; Aggarwal, M M; Arora, R; Alexandrov, Y A; Azimov, S A; Badyal, S K; Basova, E; Bhalla, K B; Bahsin, A; Bhatia, V S; Bomdarenko, R A; Burnett, T H; Cai, X; Chernova, L P; Chernyavski, M M; Dressel, B; Friedlander, E M; Gadzhieva, S I; Ganssauge, E R; Garpman, S; Gerassimov, S G; Gill, A; Grote, J; Gulamov, K G; Gulyamov, V G; Gupta, V K; Hackel, S; Heckman, H H; Jakobsson, B; Judek, B; Katroo, S; Kadyrov, F G; Kallies, H; Karlsson, L; Kaul, G L; Kaur, M; Kharlamov, S P; Kohli, J; Kumar, V; Lal, P; Larionova, V G; Lindstrom, P J; Liu, L S; Lokanathan, S; Lord, J; Lukicheva, N S; Mangotra, L K; Maslennikova, N V; Mitta, I S; Monnand, E; Mookerjee, S; Mueller, C; Nasyrov, S H; Nvtny, V S; Orlova, G I; Otterlund, I; Peresadko, N G; Persson, S; Petrov, N V; Qian, W Y; Raniwala, R; Raniwala, S; Rao, N K; Rhee, J Y; Shaidkhanov, N; Salmanova, N G; Schulz, W; Schussler, F; Shukla, V S; Skelding, D; Soederstroe,

    1989-10-01

    Multiplicity distributions and pseudo-rapidity distributions of charged particles from oxygen-induced nuclear reactions at 14.6 and 60 GeV/nucleon are presented. The data were taken from the EMU{minus}01 emulsion stacks and compared to simulations from the Lund Monte Carlo Model (FRITIOF).

  19. The quantitative determination of trace elements in giant unicellular plants by particle-induced X-ray emission

    International Nuclear Information System (INIS)

    Navarrete-Dominguez, V.R.; Yoshihara, K.; Tanaka, N.

    1982-01-01

    Particle-induced X-ray emission (PIXE) was applied for the determination of trace elements in biologically interesting materials, giant unicellular plants. It was found that the PIXE method had advantages in multi-element trace analysis of a single cell of the sample plant. (author)

  20. Humoral Immune Response Induced by PLGA Micro Particle Coupled Newcastle Disease Virus Vaccine in Chickens

    Directory of Open Access Journals (Sweden)

    Sanganagouda K

    2014-02-01

    Full Text Available This experiment was conducted for evaluating the humoral immune responses induced by Poly Lactide-co-Glycolide Acid (PLGA microspheres coupled inactivated Newcastle Disease Virus (NDV vaccine in comparison to an ‘in-house’ prepared inactivated and a live commercial vaccine. PLG microparticles containing inactivated NDV were prepared by a double emulsion technique based on solvent evaporation method. The size of the NDV coupled PLG microparticles was determined by Electron Microscopy. NDV coupled PLG microparticles were spherical having smooth surface, hollow core inside with no pores on the surface. The experiment was conducted in four groups of chickens (n=15. The encapsulation efficiency of NDV coupled PLG microparticles was determined by protein estimation and HA activity in elute. The mean (± SE size of PLG microspheres was found to be 2.409 ± 0.65 µm. The mean percent of encapsulation efficiency of PLG microspheres coupled to NDV was assessed based on the total protein content and HA activity in elute was found to be 8.03 ± 0.50 and 12.5 ± 0.00, respectively. In conclusion, the results of the experiment showed that PLGA coupled NDV vaccine elicited stronger and prolonged humoral immune response in chickens, in comparison to the other tested vaccines, as assessed by haemagglutination inhibition and enzyme linked immuno sorbent asaay titers.

  1. The influence of ligand charge and length on the assembly of Brome mosaic virus derived virus-like particles with magnetic core

    Science.gov (United States)

    Mieloch, Adam A.; Krecisz, Monika; Rybka, Jakub D.; Strugała, Aleksander; Krupiński, Michał; Urbanowicz, Anna; Kozak, Maciej; Skalski, Bohdan; Figlerowicz, Marek; Giersig, Michael

    2018-03-01

    Virus-like particles (VLPs) have sparked a great interest in the field of nanobiotechnology and nanomedicine. The introduction of superparamagnetic nanoparticles (SPIONs) as a core, provides potential use of VLPs in the hyperthermia therapy, MRI contrast agents and magnetically-powered delivery agents. Magnetite NPs also provide a significant improvement in terms of VLPs stability. Moreover employing viral structural proteins as self-assembling units has opened a new paths for targeted therapy, drug delivery systems, vaccines design, and many more. In many cases, the self-assembly of a virus strongly depends on electrostatic interactions between positively charged groups of the capsid proteins and negatively charged nucleic acid. This phenomenon imposes the negative net charge as a key requirement for the core nanoparticle. In our experiments, Brome mosaic virus (BMV) capsid proteins isolated from infected plants Hordeum vulgare were used. Superparamagnetic iron oxide nanoparticles (Fe3O4) with 15 nm in diameter were synthesized by thermal decomposition and functionalized with COOH-PEG-PL polymer or dihexadecylphosphate (DHP) in order to provide water solubility and negative charge required for the assembly. Nanoparticles were characterized by Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), Zeta Potential, Fourier Transformed Infrared Spectroscopy (FTIR) and Superconducting Quantum Interference Device (SQUID) magnetometry. TEM and DLS study were conducted to verify VLPs creation. This study demonstrates that the increase of negative surface charge is not a sufficient factor determining successful assembly. Additional steric interactions provided by longer ligands are crucial for the assembly of BMV SPION VLPs and may enhance the colloidal stability.

  2. The influence of ligand charge and length on the assembly of Brome mosaic virus derived virus-like particles with magnetic core

    Directory of Open Access Journals (Sweden)

    Adam A. Mieloch

    2018-03-01

    Full Text Available Virus-like particles (VLPs have sparked a great interest in the field of nanobiotechnology and nanomedicine. The introduction of superparamagnetic nanoparticles (SPIONs as a core, provides potential use of VLPs in the hyperthermia therapy, MRI contrast agents and magnetically-powered delivery agents. Magnetite NPs also provide a significant improvement in terms of VLPs stability. Moreover employing viral structural proteins as self-assembling units has opened a new paths for targeted therapy, drug delivery systems, vaccines design, and many more. In many cases, the self-assembly of a virus strongly depends on electrostatic interactions between positively charged groups of the capsid proteins and negatively charged nucleic acid. This phenomenon imposes the negative net charge as a key requirement for the core nanoparticle. In our experiments, Brome mosaic virus (BMV capsid proteins isolated from infected plants Hordeum vulgare were used. Superparamagnetic iron oxide nanoparticles (Fe3O4 with 15 nm in diameter were synthesized by thermal decomposition and functionalized with COOH-PEG-PL polymer or dihexadecylphosphate (DHP in order to provide water solubility and negative charge required for the assembly. Nanoparticles were characterized by Transmission Electron Microscopy (TEM, Dynamic Light Scattering (DLS, Zeta Potential, Fourier Transformed Infrared Spectroscopy (FTIR and Superconducting Quantum Interference Device (SQUID magnetometry. TEM and DLS study were conducted to verify VLPs creation. This study demonstrates that the increase of negative surface charge is not a sufficient factor determining successful assembly. Additional steric interactions provided by longer ligands are crucial for the assembly of BMV SPION VLPs and may enhance the colloidal stability.

  3. Asymmetrical Polyhedral Configuration of Giant Vesicles Induced by Orderly Array of Encapsulated Colloidal Particles.

    Science.gov (United States)

    Natsume, Yuno; Toyota, Taro

    2016-01-01

    Giant vesicles (GVs) encapsulating colloidal particles by a specific volume fraction show a characteristic configuration under a hypertonic condition. Several flat faces were formed in GV membrane with orderly array of inner particles. GV shape changed from the spherical to the asymmetrical polyhedral configuration. This shape deformation was derived by entropic interaction between inner particles and GV membrane. Because a part of inner particles became to form an ordered phase in the region neighboring the GV membrane, free volume for the other part of particles increased. Giant vesicles encapsulating colloidal particles were useful for the model of "crowding effect" which is the entropic interaction in the cell.

  4. Sintered indium-tin oxide particles induce pro-inflammatory responses in vitro, in part through inflammasome activation.

    Directory of Open Access Journals (Sweden)

    Melissa A Badding

    Full Text Available Indium-tin oxide (ITO is used to make transparent conductive coatings for touch-screen and liquid crystal display electronics. As the demand for consumer electronics continues to increase, so does the concern for occupational exposures to particles containing these potentially toxic metal oxides. Indium-containing particles have been shown to be cytotoxic in cultured cells and pro-inflammatory in pulmonary animal models. In humans, pulmonary alveolar proteinosis and fibrotic interstitial lung disease have been observed in ITO facility workers. However, which ITO production materials may be the most toxic to workers and how they initiate pulmonary inflammation remain poorly understood. Here we examined four different particle samples collected from an ITO production facility for their ability to induce pro-inflammatory responses in vitro. Tin oxide, sintered ITO (SITO, and ventilation dust particles activated nuclear factor kappa B (NFκB within 3 h of treatment. However, only SITO induced robust cytokine production (IL-1β, IL-6, TNFα, and IL-8 within 24 h in both RAW 264.7 mouse macrophages and BEAS-2B human bronchial epithelial cells. Our lab and others have previously demonstrated SITO-induced cytotoxicity as well. These findings suggest that SITO particles activate the NLRP3 inflammasome, which has been implicated in several immune-mediated diseases via its ability to induce IL-1β release and cause subsequent cell death. Inflammasome activation by SITO was confirmed, but it required the presence of endotoxin. Further, a phagocytosis assay revealed that pre-uptake of SITO or ventilation dust impaired proper macrophage phagocytosis of E. coli. Our results suggest that adverse inflammatory responses to SITO particles by both macrophage and epithelial cells may initiate and propagate indium lung disease. These findings will provide a better understanding of the molecular mechanisms behind an emerging occupational health issue.

  5. Gravitational perturbation of the BTZ black hole induced by test particles and weak cosmic censorship in AdS spacetime

    International Nuclear Information System (INIS)

    Rocha, Jorge V.; Cardoso, Vitor

    2011-01-01

    We analyze the gravitational perturbations induced by particles falling into a three dimensional, asymptotically AdS black hole geometry. More specifically, we solve the linearized perturbation equations obtained from the geodesic motion of a ringlike distribution of test particles in the BTZ background. This setup ensures that the U(1) symmetry of the background is preserved. The nonasymptotic flatness of the background raises difficulties in attributing the significance of energy and angular momentum to the conserved quantities of the test particles. This issue is well known but, to the best of our knowledge, has never been addressed in the literature. We confirm that the naive expressions for energy and angular momentum are the correct definitions. Finally, we put an asymptotically AdS version of the weak cosmic censorship to a test: by attempting to overspin the BTZ black hole with test particles it is found that the black hole cannot be spun-up past its extremal limit.

  6. The Impact of Central and Peripheral Cyclooxygenase Enzyme Inhibition on Exercise-Induced Elevations in Core Body Temperature.

    Science.gov (United States)

    Veltmeijer, Matthijs T W; Veeneman, Dineke; Bongers, Coen C C W; Netea, Mihai G; van der Meer, Jos W; Eijsvogels, Thijs M H; Hopman, Maria T E

    2017-05-01

    Exercise increases core body temperature (T C ) due to metabolic heat production. However, the exercise-induced release of inflammatory cytokines including interleukin-6 (IL-6) may also contribute to the rise in T C by increasing the hypothalamic temperature set point. This study investigated whether the exercise-induced increase in T C is partly caused by an altered hypothalamic temperature set point. Fifteen healthy, active men age 36 ± 14 y were recruited. Subjects performed submaximal treadmill exercise in 3 randomized test conditions: (1) 400 mg ibuprofen and 1000 mg acetaminophen (IBU/APAP), (2) 1000 mg acetaminophen (APAP), and (3) a control condition (CTRL). Acetaminophen and ibuprofen were used to block the effect of IL-6 at a central and peripheral level, respectively. T C , skin temperature, and heart rate were measured continuously during the submaximal exercise tests. Baseline values of T C , skin temperature, and heart rate did not differ across conditions. Serum IL-6 concentrations increased in all 3 conditions. A significantly lower peak T C was observed in IBU/APAP (38.8°C ± 0.4°C) vs CTRL (39.2°C ± 0.5°C, P = .02) but not in APAP (38.9°C ± 0.4°C) vs CTRL. Similarly, a lower ΔT C was observed in IBU/APAP (1.7°C ± 0.3°C) vs CTRL (2.0°C ± 0.5°C, P exercise compared with a CTRL. This observation suggests that a prostaglandin-E2-induced elevated hypothalamic temperature set point may contribute to the exercise-induced rise in T C .

  7. Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations.

    Science.gov (United States)

    Müller, F; Lenz, C; Dolder, P; Lang, U; Schmidt, A; Liechti, M; Borgwardt, S

    2017-12-01

    It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system. 100 μg LSD was administrated orally to 20 healthy participants prior to fMRI assessment. Whole brain thalamic functional connectivity was measured using ROI-to-ROI and ROI-to-voxel approaches. Correlation analyses were used to explore relationships between thalamic connectivity to regions involved in auditory and visual hallucinations and subjective ratings on auditory and visual drug effects. LSD caused significant alterations in all dimensions of the 5D-ASC scale and significantly increased thalamic functional connectivity to various cortical regions. Furthermore, LSD-induced functional connectivity measures between the thalamus and the right fusiform gyrus and insula correlated significantly with subjective auditory and visual drug effects. Hallucinogenic drug effects might be provoked by facilitations of cortical excitability via thalamocortical interactions. Our findings have implications for the understanding of the mechanism of action of hallucinogenic drugs and provide further insight into the role of the 5-HT 2A -receptor in altered states of consciousness. © 2017 The Authors Acta Psychiatrica Scandinavica Published by John Wiley & Sons Ltd.

  8. New Parameterizations for Neutral and Ion-Induced Sulfuric Acid-Water Particle Formation in Nucleation and Kinetic Regimes

    Science.gov (United States)

    Määttänen, Anni; Merikanto, Joonas; Henschel, Henning; Duplissy, Jonathan; Makkonen, Risto; Ortega, Ismael K.; Vehkamäki, Hanna

    2018-01-01

    We have developed new parameterizations of electrically neutral homogeneous and ion-induced sulfuric acid-water particle formation for large ranges of environmental conditions, based on an improved model that has been validated against a particle formation rate data set produced by Cosmics Leaving OUtdoor Droplets (CLOUD) experiments at European Organization for Nuclear Research (CERN). The model uses a thermodynamically consistent version of the Classical Nucleation Theory normalized using quantum chemical data. Unlike the earlier parameterizations for H2SO4-H2O nucleation, the model is applicable to extreme dry conditions where the one-component sulfuric acid limit is approached. Parameterizations are presented for the critical cluster sulfuric acid mole fraction, the critical cluster radius, the total number of molecules in the critical cluster, and the particle formation rate. If the critical cluster contains only one sulfuric acid molecule, a simple formula for kinetic particle formation can be used: this threshold has also been parameterized. The parameterization for electrically neutral particle formation is valid for the following ranges: temperatures 165-400 K, sulfuric acid concentrations 104-1013 cm-3, and relative humidities 0.001-100%. The ion-induced particle formation parameterization is valid for temperatures 195-400 K, sulfuric acid concentrations 104-1016 cm-3, and relative humidities 10-5-100%. The new parameterizations are thus applicable for the full range of conditions in the Earth's atmosphere relevant for binary sulfuric acid-water particle formation, including both tropospheric and stratospheric conditions. They are also suitable for describing particle formation in the atmosphere of Venus.

  9. The influence of laser-particle interaction in laser induced breakdown spectroscopy and laser ablation inductively coupled plasma spectrometry

    International Nuclear Information System (INIS)

    Lindner, Helmut; Loper, Kristofer H.; Hahn, David W.; Niemax, Kay

    2011-01-01

    Particles produced by previous laser shots may have significant influence on the analytical signal in laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma (LA-ICP) spectrometry if they remain close to the position of laser sampling. The effects of these particles on the laser-induced breakdown event are demonstrated in several ways. LIBS-experiments were conducted in an ablation cell at atmospheric conditions in argon or air applying a dual-pulse arrangement with orthogonal pre-pulse, i.e., plasma breakdown in a gas generated by a focussed laser beam parallel and close to the sample surface followed by a delayed crossing laser pulse in orthogonal direction which actually ablates material from the sample and produces the LIBS plasma. The optical emission of the LIBS plasma as well as the absorption of the pre-pulse laser was measured. In the presence of particles in the focus of the pre-pulse laser, the plasma breakdown is affected and more energy of the pre-pulse laser is absorbed than without particles. As a result, the analyte line emission from the LIBS plasma of the second laser is enhanced. It is assumed that the enhancement is not only due to an increase of mass ablated by the second laser but also to better atomization and excitation conditions favored by a reduced gas density in the pre-pulse plasma. Higher laser pulse frequencies increase the probability of particle-laser interaction and, therefore, reduce the shot-to-shot line intensity variation as compared to lower particle loadings in the cell. Additional experiments using an aerosol chamber were performed to further quantify the laser absorption by the plasma in dependence on time both with and without the presence of particles. The overall implication of laser-particle interactions for LIBS and LA-ICP-MS/OES are discussed.

  10. The influence of laser-particle interaction in laser induced breakdown spectroscopy and laser ablation inductively coupled plasma spectrometry

    Science.gov (United States)

    Lindner, Helmut; Loper, Kristofer H.; Hahn, David W.; Niemax, Kay

    2011-02-01

    Particles produced by previous laser shots may have significant influence on the analytical signal in laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma (LA-ICP) spectrometry if they remain close to the position of laser sampling. The effects of these particles on the laser-induced breakdown event are demonstrated in several ways. LIBS-experiments were conducted in an ablation cell at atmospheric conditions in argon or air applying a dual-pulse arrangement with orthogonal pre-pulse, i.e., plasma breakdown in a gas generated by a focussed laser beam parallel and close to the sample surface followed by a delayed crossing laser pulse in orthogonal direction which actually ablates material from the sample and produces the LIBS plasma. The optical emission of the LIBS plasma as well as the absorption of the pre-pulse laser was measured. In the presence of particles in the focus of the pre-pulse laser, the plasma breakdown is affected and more energy of the pre-pulse laser is absorbed than without particles. As a result, the analyte line emission from the LIBS plasma of the second laser is enhanced. It is assumed that the enhancement is not only due to an increase of mass ablated by the second laser but also to better atomization and excitation conditions favored by a reduced gas density in the pre-pulse plasma. Higher laser pulse frequencies increase the probability of particle-laser interaction and, therefore, reduce the shot-to-shot line intensity variation as compared to lower particle loadings in the cell. Additional experiments using an aerosol chamber were performed to further quantify the laser absorption by the plasma in dependence on time both with and without the presence of particles. The overall implication of laser-particle interactions for LIBS and LA-ICP-MS/OES are discussed.

  11. Particle formation induced by sonication during yogurt fermentation - Impact of exopolysaccharide-producing starter cultures on physical properties.

    Science.gov (United States)

    Körzendörfer, Adrian; Nöbel, Stefan; Hinrichs, Jörg

    2017-07-01

    Two major quality defects of yogurt are syneresis and the presence of large particles, and several reasons have been extensively discussed. Vibrations during fermentation, particularly generated by pumps, must be considered as a further cause as latest research showed that both ultrasound and low frequencies induced visible particles. The aim of this study was to investigate the impact of sonication during fermentation with starter cultures differing in exopolysaccharide (EPS) synthesis on the physical properties of set (syneresis, firmness) and stirred yogurt (large particles, laser diffraction, rheology). Skim milk was fermented with starter cultures YC-471 (low EPS) or YF-L 901 (high EPS) (Chr. Hansen) and sonicated for 5min at pH5.2. Sonicated set gels exhibited syneresis and were softer than respective controls. The mechanical treatment was adjusted to quantify visible particles (d≥0.9mm) in stirred yogurts properly. Sonication significantly increased particle numbers, however, the effect was less pronounced when YF-L 901 was used, indicating EPS as a tool to reduce syneresis and particle formation due to vibrations. Rheological parameters and size of microgel particles were rather influenced by starter cultures than by sonication. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. A new setup for the investigation of swift heavy ion induced particle emission and surface modifications

    Energy Technology Data Exchange (ETDEWEB)

    Meinerzhagen, F.; Breuer, L.; Bukowska, H.; Herder, M.; Schleberger, M.; Wucher, A. [Fakultät für Physik, Universität Duisburg-Essen and Cenide, 47057 Duisburg (Germany); Bender, M.; Severin, D. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Lebius, H. [CIMAP (CEA-CNRS-ENSICAEN-UCN), 14070 Caen Cedex 5 (France)

    2016-01-15

    The irradiation with fast ions with kinetic energies of >10 MeV leads to the deposition of a high amount of energy along their trajectory (up to several ten keV/nm). The energy is mainly transferred to the electronic subsystem and induces different secondary processes of excitations, which result in significant material modifications. A new setup to study these ion induced effects on surfaces will be described in this paper. The setup combines a variable irradiation chamber with different techniques of surface characterizations like scanning probe microscopy, time-of-flight secondary ion, and neutral mass spectrometry, as well as low energy electron diffraction under ultra high vacuum conditions, and is mounted at a beamline of the universal linear accelerator (UNILAC) of the GSI facility in Darmstadt, Germany. Here, samples can be irradiated with high-energy ions with a total kinetic energy up to several GeVs under different angles of incidence. Our setup enables the preparation and in situ analysis of different types of sample systems ranging from metals to insulators. Time-of-flight secondary ion mass spectrometry enables us to study the chemical composition of the surface, while scanning probe microscopy allows a detailed view into the local electrical and morphological conditions of the sample surface down to atomic scales. With the new setup, particle emission during irradiation as well as persistent modifications of the surface after irradiation can thus be studied. We present first data obtained with the new setup, including a novel measuring protocol for time-of-flight mass spectrometry with the GSI UNILAC accelerator.

  13. Photo induced multiple fragmentation of atoms and molecules: Dynamics of Coulombic many-particle systems studied with the COLTRIMS reaction microscope

    International Nuclear Information System (INIS)

    Czasch, A.; Schmidt, L.Ph.H.; Jahnke, T.; Weber, Th.; Jagutzki, O.; Schoessler, S.; Schoeffler, M.S.; Doerner, R.; Schmidt-Boecking, H.

    2005-01-01

    Many-particle dynamics in atomic and molecular physics has been investigated by using the COLTRIMS reaction microscope. The COLTRIMS technique visualizes photon and ion induced many-particle fragmentation processes in the eV and milli-eV regime. It reveals the complete momentum pattern in atomic and molecular many-particle reactions comparable to the bubble chamber in nuclear physics

  14. Air bubble-induced detachment of positively and negatively charged polystyrene particles from collector surfaces in a parallel-plate flow chamber

    NARCIS (Netherlands)

    Gomez-Suarez, C; Van der Mei, HC; Busscher, HJ

    2000-01-01

    Electrostatic interactions between colloidal particles and collector surfaces were found tcr be important in particle detachment as induced by the passage of air bubbles in a parallel-plate Row chamber. Electrostatic interactions between adhering particles and passing air bubbles, however, a-ere

  15. Forensic analysis of tempered sheet glass by particle induced X-ray emission (PIXE)

    Energy Technology Data Exchange (ETDEWEB)

    Jisonna, L.J. [Department of Chemistry and Department of Physics, Hope College, Holland, MI 49422-9000 (United States); DeYoung, P.A., E-mail: deyoung@hope.ed [Department of Chemistry and Department of Physics, Hope College, Holland, MI 49422-9000 (United States); Ferens, J.; Hall, C.; Lunderberg, J.M.; Mears, P. [Department of Chemistry and Department of Physics, Hope College, Holland, MI 49422-9000 (United States); Padilla, D. [Department of Physics, San Diego State University, San Diego, CA 92182-1233 (United States); Peaslee, G.F. [Department of Chemistry and Department of Physics, Hope College, Holland, MI 49422-9000 (United States); Sampson, R. [Department of Physics, Columbia University, New York, NY 10027 (United States)

    2011-05-15

    Highlights: {yields} PIXE was found to give the same results for trace elements in glass as ICP. {yields} PIXE can non-destructively determine trace element concentrations in auto glass. {yields} Measured Ca, Fe, Ti, Mn, and Sr in auto glass with PIXE. -- Abstract: The elemental concentrations of five trace elements in tempered sheet glass fragments were determined using particle-induced X-ray emission (PIXE) spectrometry. The trace element concentrations for calcium, iron, manganese, strontium, and titanium are compared to those obtained by inductively-coupled plasma-atomic emission spectrometry (ICP-AES) following complete digestion by hydrofluoric acid. For these five elements, the absolute concentrations obtained by both methods are shown to agree well over a wide range of concentrations. The limits of detection for trace elements are typically lower for the ICP-AES method. However, we show that the concentrations of these five elements can be accurately measured by the PIXE method. Since PIXE is an entirely non-destructive method, there exists a niche for this technique to be used as a complement to the more sensitive ICP-AES technique in the forensic analysis of sheet glass.

  16. Expression of intracis