High-intensity Electric Fields Research Articles

A fast high-intensity pulsed electric fields (PEF)-assisted extraction of dissoluble calcium from bone

A novel high-intensity pulsed electric fields (PEF) technique for the extraction of dissoluble calcium from bone is proposed. Various experimental conditions of the PEF treatment, such as electric field strength (0–70 kV/cm), pulse numbers (0–12) and citric acid concentration (0–2%) were investigated. The results showed that the extraction content of dissoluble calcium was increased with the more pulse number and the higher electric field intensity. The most content of dissoluble calcium can be achieved at 4324.8 mg/l by PEF on the conditions of 1.25% citric acid, 70 kV/cm electric field strength and 12 pulse numbers. Comparing it with the traditional assistant extraction methods, such as the boiling method and the microwave method, the extraction time by PEF was the shortest one (pulse number C = 12) and the content of dissoluble calcium by PEF was much more. Moreover, nutriments were remained in bone. At the same time, it is a non-thermal and efficient method, which has the higher speed and consumes lower energy.

Development of a direct three-dimensional biomicrofabrication concept based on electrospraying a custom made siloxane sol.

We demonstrate here the discovery of a unique and direct three-dimensional biomicrofabrication concept possessing the ability to revolutionize the jet-based fabrication arena. Previous work carried out on similar jet-based approaches have been successful in fabricating only vertical wallpillar-structures by the controlled deposition of stacked droplets. However, these advanced jet-techniques have not been able to directly fabricate self-supporting archeslinks (without molds or reaction methods) between adjacent structures (walls or pillars). Our work reported here gives birth to a unique type of jet determined by high intensity electric fields, which is derived from a specially formulated siloxane sol. The sol studied here has been chosen for its attractive properties (such as an excellent cross-linking nature as well as the ability to polymerize via polycondensation on deposition to its biocompatability), which promotes direct forming of biostructures with nanometer (<50 nm) sized droplets in three dimensions. We foresee that this direct three-dimensional biomicrofabrication jet technique coupled with a variety of formulated sols having focused and enhanced functionality will be explored throughout the physical and life sciences.

Bio‐electrosprays: A novel electrified jetting methodology for the safe handling and deployment of primary living organisms

Electrohydrodynamic jetting (EHDJ) which is also known as electrosprays (ES) has recently been elucidated as a unique electrified biotechnique for the safe handling and deployment of living organisms. This high intensity electric field driven jetting methodology is now referred to as "bioelectrosprays" (BES). Previously these charged jets have only been shown to jet-process immortalized cells which have undergone expected cellular behavior when compared with control cells. In this paper we demonstrate the ability to jet process primary living organisms in the stable conejetting mode. Finally the viability of the bio-electrosprayed living organisms has been assessed employing a flow cytometry approach which forms the discussion in this paper. Our findings further establish BES as a competing biotechnique, which could be employed for the deposition of primary living organisms according to a predetermined active cellular architecture. One day this could be used for the fabrication of viable tissues and organs for repair or replacement. These advanced studies carried out on BES have direct widespread applications ranging from developmental biology to regenerative and therapeutic medicine, which are a few amongst several other areas of study within the life sciences.

Self-electroporation as a Model for Fusion Pore Formation

The creation of a small opening called the fusion pore is a necessary prerequisite for neurotransmitter release from synaptic vesicles. It is known that high intensity electric fields can create pores in vesicles by a process called electroporation. Due to the presence of charged phosphatidylserine (PS) molecules on the inner leaflet of the cell membrane, an electric field that is strong enough to cause electroporation of a synaptic vesicle might be present. It was shown by K. Rosenheck [K. Rosenheck. Biophys J 75, 1237–1243 (1998)] that in a planar geometry, fields sufficient to cause electroporation can occur at intermembrane separations of less than ∼3 nm. It is frequently found, however, that the cell membrane is not planar but caves inward at the locations where a vesicle is close to it. Indentation of the cell membrane in the fusion region was modelled as a hemisphere and a theoretical study of the electric field in the vicinity of the cell membrane taking into account the screening effect of dissolved ions in the cytoplasm was performed. It was discovered that fields crossing the electroporation threshold occurred at a distance of 2 nm or less, supporting the claim that electroporation could be a possible mechanism for fusion pore formation.

Electrically Assisted Ocular Gene Therapy

Electrotransfer and iontophoresis are being developed as innovative non-viral gene delivery systems for the treatment of eye diseases. These two techniques rely on the use of electric current to allow for higher transfection yield of various ocular cell types in vivo. Short pulses of relatively high-intensity electric fields are used for electrotransfer delivery, whereas the iontophoresis technique is based on the application of low voltage electric current. The basic principles of these techniques and their potential therapeutic application for diseases of the anterior and posterior segments of the eye are reviewed. Iontophoresis has been found most efficient for the delivery of small nucleic acid fragments such as antisense oligonucleotides, siRNA, or ribozymes. Electrotransfer, on the other hand, is being developed for the delivery of oligonucleotides or custom designed plasmids. The wide range of strategies already validated and the potential for targeting specific types of cells confirm the promising early observations made using electrotransfer and iontophoresis. These two nonviral delivery systems are safe and can be used efficiently for targeted gene delivery to ocular tissues in vivo. At the present, their application for the treatment of ocular human diseases is nearing its final stages of adaptation and practical implementation at the bedside.

Sulphur dioxide (SO2) electrotransfer in electric field generated by corona discharge

The mechanism of the forming SO2 negative ions and their electrotransfer in the corona discharge electric field was investigated in this paper. The experimental results showed that SO2 electrotransfer occurred in the electric field with corona discharge, which had potential applications in removal of SO2 of the flue gas from coal-fired power plants by electrotransfer. SO2 electrotransfer was enhanced by higher electric-field intensity or a larger discharging area. Assistant uniform electric field after the corona discharge electric field would improve SO2 electrotransfer. The increment of the desulphurization efficiency by SO2 electrotransfer might reach as high as 50%.

An investigation on pulsed electric fields technology using new treatment chamber design

A pulsed electric field (PEF) system was designed and constructed using modern IGBT technology. The main focus of this work was to design a new PEF treatment chamber that operate at high electric field intensities with limited increase in liquid temperature and limited fouling of electrodes. Four multi-pass treatment chambers were designed consisting of two stainless steel mesh electrodes in each chamber, with the treated fluid flowing through the openings of the mesh electrodes. The two electrodes are electrically isolated from each other by an insulator element designed to form a small orifice where most of the electric field is concentrated. Dielectric breakdown inside the chambers was prevented by removing the electrodes far from the narrow gap. The effect of PEF treatment on the inactivation of gram-negative Escherichia coli ATCC 25922 suspended in simulated milk ultra-filtrate (SMUF) of 100%, 66.67% and 50% w/w was investigated. Treatments with the same electrical input power but with higher electric field strengths provided larger degree of killing. The effect of PEF treatment using suspensions at different flow rates and different pulse frequencies was also investigated. In general, the inactivation rate of E. coli increased with increasing electric field strength, treatment time and processing temperature. More than 6 log reductions in E. coli suspended in SMUF was achieved using electric field intensity in the range of (37.2–49.6 kV/cm) with a treatment temperature not exceeding 38 °C.

El proceso tradicional de elaboración del pimentón de Murcia y sus posibles innovaciones

The traditional method of Spanish paprika processing in the Murcia Region is under the official category Denomination of Origin “Paprika of Murcia”. The process consists basically in manual harvesting the fruit in full ripe stage, drying, removing the peduncle and seeds, hammer and stone milling for crushing and grinding, transmission, mixing and granulating, sterilization, packaging and refrigerated storage. The details about the paprika processing operations are reported. In a second part the main control points of paprika processing, paprika quality traits and risks are also mentioned. The innovations proposed for paprika processing and unit operations in the literature include application of hygienic food processing design, paprika processing in a nitrogen flow, heat pretreatments before grinding or applied to shredded pepper, high hydrostatic pressure or high intensity electrical field pulse, irradiation, osmotic dehydration, lyophilization, mixing and coating, and modified atmosphere packaging. The traditional method of Spanish paprika processing in the Murcia Region is under the official category Denomination of Origin “Paprika of Murcia”. The process consists basically in manual harvesting the fruit in full ripe stage, drying, removing the peduncle and seeds, hammer and stone milling for crushing and grinding, transmission, mixing and granulating, sterilization, packaging and refrigerated storage. The details about the paprika processing operations are reported. In a second part the main control points of paprika processing, paprika quality traits and risks are also mentioned. The innovations proposed for paprika processing and unit operations in the literature include application of hygienic food processing design, paprika processing in a nitrogen flow, heat pretreatments before grinding or applied to shredded pepper, high hydrostatic pressure or high intensity electrical field pulse, irradiation, osmotic dehydration, lyophilization, mixing and coating, and modified atmosphere packaging.

Optimized apertureless optical near-field probes with 15 nm optical resolution

Back-illuminated full body glass tips coated with a thin metal layer can be used aslocal probes for apertureless scanning near-field optical microscopy (SNOM). Inorder to achieve high spatial resolution, high electric field intensities and lowbackground illumination, the thickness of the metal coating, angular illuminationdirection, and polarization have to be optimized. Optimal conditions have beencalculated and experimentally verified for 10–15 nm thick aluminium and 15–25 nmthick silver layers. Upon imaging single dye molecules, characteristic single anddouble-peak patterns with peak widths down to 15 nm could be measured, exhibiting anoptical resolution which exceeds the classical diffraction limit of Abbé significantly.

Polaron Injection into One-Dimensional Polydiacetylene Nanowire

A polydiacetylene nanowire fabricated on a highly ordered pyrolytic graphite surface was studied by scanning tunneling microscopy/spectroscopy (STM/STS). The spectroscopy of individual polydiacetylene nanowires revealed the theoretically predicted π-band and band edge singularities, which are characteristics of a one-dimensional π-conjugated polymer. Furthermore, under a high electric field intensity applied to the polymer wire, the spectrum shows a narrow band gap caused by polaron injection. When a much higher electric field intensity was applied to the wire, an avalanche current flow that rises abruptly has been observed. We consider that such a large current flow originates from an electrical property of the polymer wire, which was changed by a dynamical modulation of the injected polaron.

Electrohydrodynamic Jet Processing: An Advanced Electric‐Field‐Driven Jetting Phenomenon for Processing Living Cells

Spraying live cells in suspension: The electrohydrodynamic jet, driven by high-intensity electric fields, can be exploited for processing living cells (see setup in the Figure). No adverse effects on the living cells have been observed when they are processed with this technique. This technology is not hampered by the disadvantages encountered with inkjets and can process concentrated biological suspensions containing living cells.

27.3: Electro-Optical Cholesteric Sheet Writing

Flexible displays having a polymer dispersed cholesteric layer, a dark layer and a thin electrical conductor have been found to respond to a combination of high-intensity xenon flash energy and electrical field. A variety of writing schemes have been discovered. Simple super-twisted-nematic displays can be used as an imaging mask. The technology further permits dry fingerprint imaging through contact printing.

Potentials of high intensity electric field pulses (HELP) to food processors in developing countries

PurposeThis paper aims to focus on the prospects of incorporating a non‐thermal process (high intensity electric field pulses, HELP) into food processing and preservation methods in developing countries. Besides, it is to create awareness to food processors and motivate researchers in developing countries to generate more data on the technology.Design/methodology/approachThis is based on the review of the various successful applications of HELP process in inactivation of micro‐organisms for the purpose of preservation. The adaptability of the process to plant food processing was also reviewed. Potential areas of application in developing countries were also highlighted and discussed.FindingsThe present findings reveal possible applications of HELP to food processing in developing countries such as fermentation, fruit and vegetable processing, and dehydration of tropical food.Originality/valueThe paper has indicated that the poor energy system in developing countries has made drying and fermentation techniques appropriate methods of food processing. Therefore, HELP technology offers good potentials for both food processing and preservation and as adjunct to other processes such as fermentation and drying.

An Antenna Impedance Measuring System for the Medium-Wave With Interference Signal Suppression Function

An impedance analyzer or the Schering bridge is usually used for measurement of the medium-wave antenna impedance. However it has been said to be impossible to measure the exact antenna impedance under a high-intensity electric field environment generated by such as a neighboring radio station, especially with the same operating frequency because an undesired large signal is induced at the antenna input port. We propose a new measurement method and an instrument using a double synchronized detection, which has a function to suppress undesired signals efficiently. Here a double synchronous detecting technique is introduced to suppress the undesired signal with the same frequency as a measurement frequency. This system makes it possible to easily measure the antenna impedance with higher accuracy even under such an environment and also is useful for periodical maintenance of the transmitting antenna without interruption of broadcasting services in the daytime.

The behaviour of a typical single-crystal Si solar cell under high intensity of electric field

Abstract The effect of high intensity of electric fields on the operation of a single-crystal Si solar cell was investigated in this work. A single-crystal Si solar cell was irradiated by spontaneous and stimulated light sources. Firstly, a triac-lamp having a tungsten filament and green, yellow, red and blue LEDs from the spontaneous light sources were used to irradiate the solar cell exposed to a high-intensity electric field EDC. Later, as a stimulated light source He–Ne laser with λ = 633.8 nm and P = 1 mW was utilized, and the behaviour of the solar cell exposed to the electric field EDC ranging from 100×103 to 500×103 V/m was studied. The results showed that the Voc value of the solar cell irradiated by the two light sources mentioned above decreased due to the electric field.

In vivo NMR imaging evaluation of efficiency and toxicity of gene electrotransfer in rat muscle

In vivo gene electrotransfer (ET) is a simple method of gene delivery in various tissues relying on the injection of plasmid DNA followed by application of electric pulses. Noninvasive tools are needed to evaluate the ET efficiency and the resulting tissue damages. In this study, we performed ET of rat tibialis muscle after injection of either a plasmid coding for luciferase or a contrast agent (CA) detected by using magnetic resonance imaging (MRI). Plasmid expression and CA intracellular trapped quantity were compared throughout the electric field intensity range 0-300 V/cm. Although the CA trapped quantity reflects only the electropermeabilization step, both measurements were correlated. MRI measurements gave easy access to tridimensional visualization of the labelled zones where the CA has been injected and the applied electric field had a value allowing permeabilization. We also performed MRI measurements of the water transverse relaxation time T2 as an indicator of tissue modification, and tested whether another CA specific for necrosis could be used to detect muscle necrosis at high electric field intensity. In conclusion, MRI measurements may bring multiparametric information upon the efficiency and tissue toxicity of an ET protocol by using a simple and safe CA.

Nanosecond Pulsed Electric Fields (nsPEF) Induce Direct Electric Field Effects and Biological Effects on Human Colon Carcinoma Cells

Nanosecond pulsed electric fields (nsPEFs) are ultrashort pulses with high electric field intensity (kV/cm) and high power (megawatts), but low energy density (mJ/cc). To determine roles for p53 in response to nsPEFs, HCT116 cells (p53+/+ and p53-/-) were exposed to nsPEF and analyzed for membrane integrity, phosphatidylserine externalization, caspase activation, and cell survival. Decreasing plasma membrane effects were observed in both HCT116p53+/+ and p53-/- cells with decreasing pulse durations and/or decreasing electric fields. However, addition of ethidium homodimer-1 and Annexin-V-FITC post-pulse demonstrated greater fluorescence in p53-/- versus p53+/+ cells, suggesting a postpulse p53-dependent biological effect at the plasma membrane. Caspase activity was significantly higher than nonpulsed cells only in the p53-/- cells. HCT116 cells exhibited greater survival in response to nsPEFs than HL-60 and Jurkat cells, but survival was more evident for HCT116p53+/+ cells than for HCT116p53-/- cells. These results indicate that nsPEF effects on HCT116 cells include (1) apparent direct electric field effects, (2) biological effects that are p53-dependent and p53-independent, (3) actions on mechanisms that originate at the plasma membranes and at intracellular structures, and (4) an apparent p53 protective effect. NsPEF applications provide a means to explore intracellular structures and functions that can reveal mechanisms in health and disease.

401 エバネッセント光による熱光起電力発電に関する研究(OS4 マイクロ流れの基礎と応用)

Near-field radiation that has a high intensity of electric field might be applied to enhancement of energy transfer. Furthermore, an increase in output power of electricity was also detected slightly through a thermophotovoltaic cell. In a vacuum chamber, the cell and the tungsten emitter were put together in face to face and in parallel with a small gap. As the gap becomes narrower than a few microns, the emitter temperature is decreased drastically, which means that heat transfer is enhanced since the input energy into the emitter is kept at constant. On further decrease in gap, the electric power increases just before contact though the emitter temperature decreases continuously.

ＥＲゲルにおけるせん断応力発生のメカニズム

ER Fluid (ERF) is a functional substance that can change its apparent viscoelastic properties by the application of an electric field. This is called the ER effect. The Applications of ERF to mechanical devices have been anticipated. However, separation and sedimentation of ER particles over long term use, which reduces the ER effect and results in low stability of ER devices, has been an obstacle to such application. To solve these problems, an ER gel was developed and the basic characteristics of ER gel were experimentally analyzed. A thin sheet of ER gel was sandwiched between a pair of plate electrodes and the variation of shear force between the ER gel sheet and the electrode was measured under variated of electric field intensity. The developed ER gel produced extremely high shear force and showed a slip phenomenon at the contact surface of the electrode under high electric field intensity. These results suggest that the developed ER gel has a different shear stress occurrence mechanism from conventional ERF. In this study, the shear stress occurrence mechanism in ER gel was also experimentally analyzed.

Modeling Studies of Cell Response to Ultrashort, High-Intensity Electric Fields—Implications for Intracellular Manipulation

The dynamics of electroporation in biological cells subjected to nanosecond, high-intensity pulses are studied based on a coupled scheme involving both the current continuity and Smoluchowski equations. A new distributed network model, that includes dynamic conductivities of cell membranes and substructures, is introduced for evaluations of transmembrane potential. It is shown that subcellular structures could be affected through nanosecond pulses, and that, despite the high field intensity, the processes remain nonthermal. As an example of selectivity, differences in cell responses between normal and malignant (Farage) tonsillar B-cells are compared and discussed. It is shown that ultrashort, high-intensity electric pulses could damage cancer cells. Finally, the model predicts that it is possible to target the inner mitochondrial membrane (i.e., selectivity at the organelle level), in keeping with recent experimental observations.