A5087589294- Microbial Inactivation Methods
- Gyrotron and Vacuum Electronics Research
- Laser Design and Applications
- Microfluidic and Bio-sensing Technologies
- Magnetic and Electromagnetic Effects
- Pulsed Power Technology Applications
- Plasma Diagnostics and Applications
- Listeria monocytogenes in Food Safety
- Plasma Applications and Diagnostics
- Laser-Plasma Interactions and Diagnostics
- Photonic and Optical Devices
- Advanced Surface Polishing Techniques
- Viral Infectious Diseases and Gene Expression in Insects
- Neuroscience and Neural Engineering
- Electrohydrodynamics and Fluid Dynamics
- Laser Material Processing Techniques
- Toxin Mechanisms and Immunotoxins
- Particle Accelerators and Free-Electron Lasers
- Plant Genetic and Mutation Studies
- Electrostatic Discharge in Electronics
- Lipid Membrane Structure and Behavior
- Particle Detector Development and Performance
- Particle accelerators and beam dynamics
- Planarian Biology and Electrostimulation
- Nanoplatforms for cancer theranostics
Old Dominion University
2015-2024
University of California, Los Angeles
2012-2016
University of Southern California
2008-2012
Auburn University
2006-2007
Background Electroporation, a method for increasing the permeability of membranes to ions and small molecules, is used in clinic with chemotherapeutic drugs cancer treatment (electrochemotherapy). Electroporation calcium causes ATP (adenosine triphosphate) depletion cell death could be novel treatment. This study aims at understanding relationship between applied electric field, concentration, efficacy. Methods In three human lines — H69 (small-cell lung cancer), SW780 (bladder U937...
The detailed molecular mechanisms underlying the permeabilization of cell membranes by pulsed electric fields (electroporation) remain obscure despite decades investigative effort. To advance beyond descriptive schematics to development robust, predictive models, empirical parameters in existing models must be replaced with physics- and biology-based terms anchored experimental observations. We report here absolute values for uptake YO-PRO-1, a small-molecule fluorescent indicator membrane...
Applications of electric-field-induced permeabilization cells range from cancer therapy to wastewater treatment. A unified understanding the underlying mechanisms membrane electropermeabilization, however, has not been achieved. Protocols are empirical, and models descriptive rather than predictive, which hampers optimization expansion electroporation-based technologies. common feature existing is assumption that permeabilized passive, transport through it entirely diffusive. To demonstrate...
Imaging of fluorescent small molecule transport into electropermeabilized cells reveals polarized patterns entry, which must reflect in some way the mechanisms migration these molecules across compromised membrane barrier. In reports, occurs primarily areas nearest positive electrode (anode), but others cathode-facing entry dominates. Here we compare YO-PRO-1, propidium, and calcein uptake U-937 after nanosecond (6 ns) microsecond (220 µs) electric pulse exposures. Each three dyes exhibits a...
Nanosecond bipolar pulse cancellation, a recently discovered phenomenon, is modulation of the effects unipolar electric exposure by second opposite polarity. This attenuation biological response reversal field direction has been reported with durations from 60 ns to 900 for wide range endpoints, and it not observed conventional electroporation pulses much longer duration (>100 μs) where are additive regardless The most plausible proposed mechanisms involve field-driven migration ions...
Excited by 5 ns, 8 kV voltage pulses, a 260 μm-diameter, mm long helium plasma jet was generated with single-electrode configuration in ambient air. Application of fast high pulses (≥1012 V s−1) resulted rapid acceleration the microplasma plumes; within ns plume velocity reached × 105 m/s, almost three times higher than that pulsed same amplitude but lower increase rate (1011 s−1). Importantly, ultrashort electric were able to efficiently deposit energy during initiation process, which may...
Dosage control of reactive oxygen and nitrogen species (RONS) is critical to low-temperature plasma applications in cancer therapy. Production RONS by atmospheric pressure, nonequilibrium plasmas contact with liquid may be modulated via conditions including treatment time pulse voltage repetition frequency. In this study, a terephthalic acid-based probe was used measure hydroxyl radicals [OH(aq)] water exposed demonstrate that the OH(aq) concentration increases linearly time. Fluorometric...
Cellular effects of nanosecond-pulsed electric field exposures can be attenuated by an reversal, a phenomenon called bipolar pulse cancellation. Our investigations this in neuroendocrine adrenal chromaffin cells show that single 2-ns, 16 MV/m unipolar elicited rapid, transient rise intracellular Ca2+ levels due to influx through voltage-gated calcium channels. The response was eliminated 2-ns with positive and negative phases equal duration amplitude fully restored (unipolar-equivalent...
Light-activated pseudospark switches, also called back-lighted thyratrons (BLTs), are low pressure, high voltage (typ. 10-50 kV), current 1-100 kA) glow-mode switches. It is of interest to develop BLTs with reliable and practical optical triggering systems for applications compact pulsed power. This paper reports the results research into photocathode materials enhance switching performance provide optimal cathode conditions triggering. Effective have many specific qualities, most important...
Abstract Although electric field–induced cell membrane permeabilization (electroporation) is used in a wide range of clinical applications from cancer therapy to cardiac ablation, the cellular- and molecular-level details processes that determine success or failure these treatments are poorly understood. Nanosecond pulsed field (nsPEF)–based tumor therapies known have an immune component, but whether how cells sense electroporative damage respond it not been demonstrated. Damage-...
Intracellular reactive oxygen species (ROS) generation is widely suggested as a trigger for biological consequences of electric field exposures, such those in electroporation applications. ROS are linked with membrane barrier function degradation, genetic damage, and complex events like immunological cell death. Dihydroethidium (DHE) commonly used to monitor cells. DHE intracellular by primary oxidation product, Ethidium (Eth
Nanosecond pulsed helium plasma jets impinging on water produce hydroxyl radicals both in gas- and liquid-phase. In this study, the effects of pulse width a repetitively jet contact with are evaluated via OH(A–X) emission OHaq production for various widths ranging from 200 to 5000 ns. The maximal energy efficiency is obtained 600–800 ns whereas at Temporally-resolved spectroscopy shows that more than 40% produced during first voltage regardless width. An equivalent circuit model compiled...
Pseudospark switches have been successfully employed in a variety of pulsed power applications including high-power electron beam sources, microwaves, and transient plasma ignition for detonation engines. For such as these, advances that improve simplify triggering are important. Here, magnesium was investigated photocathode candidate optically triggered pseudospark switches, also called back-lighted thyratrons (BLTs). A Mg foil on the back surface copper BLT cathode reduced trigger delay...
The Gram-positive anaerobic bacterium Cutibacterium acnes (C. acnes) is a commensal of the human skin, but also an opportunistic pathogen that contributes to pathophysiology skin disease acne vulgaris. C. can form biofilms; cells in biofilms are more resilient antimicrobial stresses. Acne therapeutic options such as topical or systemic treatments often show incomplete responses. In this study we measured efficacy nanosecond pulsed electric fields (nsPEF), new promising cell and tissue...
In this paper we present our work on breakdown studies conducted in helium at partial vacuum conditions for a point-to-point electrode setup. A high frequency pulsed voltage signal is applied across the electrodes and voltage-current characteristics are observed. The consists of train square pulses range 50 to 200 kHz with 50% duty cycle rise/fall times 20-30 ns. These were understand compare role pulse repetition rate electrical initiation low pressure conditions. Preliminary data current...
We describe experimental measurements of energy modulation obtained using the Micro Accelerator Platform (MAP), a slab-symmetric dielectric laser accelerator based on resonant structure, at SLAC E-163 beamline. The structure is powered by Ti:Sapphire side-coupled into vacuum gap, where MAP’s periodicity and dimensions create synchronous accelerating mode. field experienced electron beam greater than that in incoming radiation an enhancement factor order 3 to 5, due buildup cavity fields....
Light-activated pseudospark switches, also called back-lighted thyratrons (BLTs), are low pressure (typ. les0.5 Torr), high voltage 10-50 kV), current (1-ges100 kA) glow-mode switches. It is of interest to develop ultra-compact BLTs with reliable and practical optical triggering systems for applications compact pulsed power. The present work investigates the utility photocathode materials inside mini-BLTs enhance switch performance, improve trigger characteristics (delay, jitter...