Bulletin of the American Physical Society
46th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 60, Number 7
Monday–Friday, June 8–12, 2015; Columbus, Ohio
Session G5: Invited Session: Collisions in Bio-Medical Plasmas |
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Chair: Thad Walker, University of Wisconsin, Madison Room: Fairfield |
Wednesday, June 10, 2015 8:00AM - 8:30AM |
G5.00001: Linking plasma kinetics to plasma-bio interactions Invited Speaker: Peter Bruggeman Cold non-equilibrium atmospheric pressure plasmas have received a lot of attention in the last decade due to their huge potential for biomedical applications. In my group, we have characterized an RF driven APPJ in great detail. The characterization includes electrical measurements, imaging, optical emission spectroscopy, (two photon enhanced) laser induced fluorescence, Thomson scattering, Rayleigh scattering, Raman scattering and mass spectrometry. This led to a detailed knowledge of the electron density, electron temperature, gas temperature, NO, O, OH, O3 densities, ionic species and air concentrations in the plasma effluent [1-3]. Living organisms for in vitro studies are typically kept in complex solutions or culture media. Plasma-bio interactions involves not only the production of reactive species in the plasma gas phase but also transport to the liquid phase and plasma induced liquid phase chemistry and its impact on the living organisms. Reactive nitrogen and oxygen species have been identified as the key reactive species [4]. Recent results of my group show that controlling the gas phase plasma chemistry can lead to significant different biological responses of the living organisms corresponding to different chemical pathways [5]. The effect of plasma jet interaction with liquids containing mammalian cells, bacteria and virus will be discussed. The outcomes of these studies allow unraveling chemical pathways responsible for plasma-bio interactions and linking plasma kinetics to plasma-bio interactions. \\[4pt] [1] A.F.H. van Gessel, et al. Appl. Phys. Lett. \textbf{103} (6) 064103 (2013)\\[0pt] [2] B.T.J. van Ham et al. J. Phys. D: Appl. Phys. \textbf{47 }(2014) 224013\\[0pt] [3] S. Zhang et al. Plasma Sources Sci. Technol. \textbf{23} 025012 (2014)\\[0pt] [4] D.B. Graves, J. Phys. D: Appl. Phys. \textbf{45,} 263001 (2012)\\[0pt] [5] K. Wende et al, Biointerphases (submitted) [Preview Abstract] |
Wednesday, June 10, 2015 8:30AM - 9:00AM |
G5.00002: Complete and consistent cross-section sets for electrons in biomolecular gases using swarm techniques Invited Speaker: Ron White The determination of a comprehensive set of electron-biomolecule cross-sections is fundamental to understanding electron induced processes arising in plasma medicine and radiation damage modelling. Formulation of complete sets is generally based on a critical assessment of available experimental ``beam'' studies and theoretical calculations, and interpolations/extropolations. Issues of completeness and accuracy of cross-section sets aris and it is here that swarm experiments play a key role. In this presentation we report on recent swarm measurements in the biomolecules of water and tetrahydrafuran (THF) using the pulsed-Townsend technique of the de Urquijo group. We present and assess the consistency of cross-section sets for water and THF through a comparison of calculated transport coefficients using a multi-term Boltzmann equation solution with the available experimental swarm measurements provides a discriminating test on consistency and accuracy of the cross-section sets. Co-authors: J. de Urquijo, M. Casey, D. Konvalov, M. J. Brunger, G. Garcia and Z. Petrovic. [Preview Abstract] |
Wednesday, June 10, 2015 9:00AM - 9:30AM |
G5.00003: Measurements of absolute radical densities in atmospheric pressure plasmas with complex gas mixtures Invited Speaker: Deborah O'Connell Low temperature plasmas are emerging as an exciting development for therapeutics. Non-equilibrium plasmas, operated at ambient atmospheric pressure and temperature, are very efficient sources for highly reactive neutral particles, including reactive oxygen and nitrogen species (RONS), which are known to play a crucial role in biological systems and existing therapeutics. Transport of these plasma components to the target is complex. In order to understand the chemical kinetics and plasma-liquid-biological interaction mechanisms measurements of the relevant RONS are key. Under atmospheric pressure these are challenging, primarily due to the multi-phase and highly collisional environment, requiring extremely high temporal (picosecond to nanosecond) and spatial (microns) resolution. Absolute measurements of radical densities (including O and OH) using picosecond two-photon absorption laser induced fluorescence (ps-TALIF), UV and high-resolution synchrotron VUV absorption spectroscopy will be presented. Fluorescence lifetime measurements of the laser-excited radicals are possible with picosecond resolution and this provides us with information about collisional quenching partners and thus collision kinetics with the surrounding environment. [Preview Abstract] |
Wednesday, June 10, 2015 9:30AM - 10:00AM |
G5.00004: Secondary particle tracks generated by ion beam irradiation Invited Speaker: Gustavo Garc\'Ia The Low Energy Particle Track Simulation (LEPTS) procedure is a powerful complementary tool to include the effect of low energy electrons and positrons in medical applications of radiation. In particular, for ion-beam cancer treatments provides a detailed description of the role of the secondary electrons abundantly generated around the Bragg peak as well as the possibility of using transmuted positron emitters (C11, O15) as a complement for ion-beam dosimetry. In this study we present interaction probability data derived from IAM-SCAR corrective factors for liquid environments. Using these data, single electron and positron tracks in liquid water and pyrimidine have been simulated providing information about energy deposition as well as the number and type of interactions taking place in any selected ``nanovolume'' of the irradiated area.\\[4pt] In collaboration with Francisco Blanco, Universidad Complutense de Madrid; Antonio Mu\~noz, Centro de Investigaciones Energ\'eticas Medioambientales y Tecnol\'ogicas; and Diogo Almeida, Filipe Ferreira da Silva, Paulo Lim\~ao-Vieira, Universidade Nova de Lisboa. [Preview Abstract] |
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