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Sample records for pulsed electric field

  1. Pulsed electric fields

    Science.gov (United States)

    The concept of pulsed electric fields (PEF) was first proposed in 1967 to change the behavior or microorganisms. The electric field phenomenon was identified as membrane rupture theory in the 1980s. Increasing the membrane permeability led to the application of PEF assisted extraction of cellular co...

  2. Cryosurgery with pulsed electric fields.

    Science.gov (United States)

    Daniels, Charlotte S; Rubinsky, Boris

    2011-01-01

    This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF) are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF) was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused PEFs could be used to

  3. Cryosurgery with pulsed electric fields.

    Directory of Open Access Journals (Sweden)

    Charlotte S Daniels

    Full Text Available This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused

  4. Cryosurgery with Pulsed Electric Fields

    Science.gov (United States)

    Daniels, Charlotte S.; Rubinsky, Boris

    2011-01-01

    This study explores the hypothesis that combining the minimally invasive surgical techniques of cryosurgery and pulsed electric fields will eliminate some of the major disadvantages of these techniques while retaining their advantages. Cryosurgery, tissue ablation by freezing, is a well-established minimally invasive surgical technique. One disadvantage of cryosurgery concerns the mechanism of cell death; cells at high subzero temperature on the outer rim of the frozen lesion can survive. Pulsed electric fields (PEF) are another minimally invasive surgical technique in which high strength and very rapid electric pulses are delivered across cells to permeabilize the cell membrane for applications such as gene delivery, electrochemotherapy and irreversible electroporation. The very short time scale of the electric pulses is disadvantageous because it does not facilitate real time control over the procedure. We hypothesize that applying the electric pulses during the cryosurgical procedure in such a way that the electric field vector is parallel to the heat flux vector will have the effect of confining the electric fields to the frozen/cold region of tissue, thereby ablating the cells that survive freezing while facilitating controlled use of the PEF in the cold confined region. A finite element analysis of the electric field and heat conduction equations during simultaneous tissue treatment with cryosurgery and PEF (cryosurgery/PEF) was used to study the effect of tissue freezing on electric fields. The study yielded motivating results. Because of decreased electrical conductivity in the frozen/cooled tissue, it experienced temperature induced magnified electric fields in comparison to PEF delivered to the unfrozen tissue control. This suggests that freezing/cooling confines and magnifies the electric fields to those regions; a targeting capability unattainable in traditional PEF. This analysis shows how temperature induced magnified and focused PEFs could be used to

  5. Pulsed electric field increases reproduction.

    Science.gov (United States)

    Panagopoulos, Dimitris J

    2016-01-01

    Purpose To study the effect of pulsed electric field - applied in corona discharge photography - on Drosophila melanogaster reproduction, possible induction of DNA fragmentation, and morphological alterations in the gonads. Materials and methods Animals were exposed to different field intensities (100, 200, 300, and 400 kV/m) during the first 2-5 days of their adult lives, and the effect on reproductive capacity was assessed. DNA fragmentation during early- and mid-oogenesis was investigated by application of the TUNEL (Terminal deoxynucleotide transferase dUTP Nick End Labeling) assay. Sections of follicles after fixation and embedding in resins were observed for possible morphological/developmental abnormalities. Results The field increased reproduction by up to 30% by increasing reproductive capacity in both sexes. The effect increased with increasing field intensities. The rate of increase diminished at the strongest intensities. Slight induction of DNA fragmentation was observed exclusively in the nurse (predominantly) and follicle cells, and exclusively at the two most sensitive developmental stages, i.e., germarium and predominantly stage 7-8. Sections of follicles from exposed females at stages of early and mid-oogennesis other than germarium and stages 7-8 did not reveal abnormalities. Conclusions (1) The specific type of electric field may represent a mild stress factor, inducing DNA fragmentation and cell death in a small percentage of gametes, triggering the reaction of the animal's reproductive system to increase the rate of gametogenesis in order to compensate the loss of a small number of gametes. (2) The nurse cells are the most sensitive from all three types of egg chamber cells. (3) The mid-oogenesis checkpoint (stage 7-8) is more sensitive to this field than the early oogenesis one (germarium) in contrast to microwave exposure. (4) Possible therapeutic applications, or applications in increasing fertility, should be investigated.

  6. Directed cell movement in pulsed electric fields.

    Science.gov (United States)

    Franke, K; Gruler, H

    1994-01-01

    Human granulocytes exposed to pulsed electric guiding fields were investigated. The trajectories were determined from digitized pictures (phase contrast). The basic results are: (i) No directed response was induced by pulsed electric guiding fields having a zero averaged field. (ii) A directed response was induced by pulsed electric guiding fields having a non-zero averaged field. (iii) The directed response was enhanced for pulse sequences having a repetition time of 8 s. (iv) The lag-time between signal recognition and cellular response was 8-10 s. The results are discussed in the framework of a self-ignition model.

  7. Pulsed electric field inactivation in a microreactor

    NARCIS (Netherlands)

    Fox, M.B.

    2006-01-01

    Pulsed electric fields (PEF) is a novel, non-thermal pasteurization method which uses short, high electric field pulses to inactivate microorganisms. The advantage of a pasteurization method like PEF compared to regular heat pasteurization is that the taste, flavour, texture and nutritional value ar

  8. Schwinger Pair Production in Pulsed Electric Fields

    CERN Document Server

    Kim, Sang Pyo; Ruffini, Remo

    2012-01-01

    We numerically investigate the temporal behavior and the structure of longitudinal momentum spectrum and the field polarity effect on pair production in pulsed electric fields in scalar quantum electrodynamics (QED). Using the evolution operator expressed in terms of the particle and antiparticle operators, we find the exact quantum states under the influence of electric pulses and measure the number of pairs of the Minkowski particle and antiparticle. The number of pairs, depending on the configuration of electric pulses, exhibits rich structures in the longitudinal momentum spectrum and undergoes diverse dynamical behaviors at the onset of the interaction but always either converges to a momentum-dependent constant or oscillates around a momentum-dependent time average after the completion of fields.

  9. Preliminary Studies on Pulsed Electric Field Breakdown of Lead Azide

    Science.gov (United States)

    1976-10-01

    1/2 OS CO ton NO. S3L TECHNICAL REPORT 4991 PRELIMINARY SUJDfES ON PULSED ELECTRIC FIELD BREAKDOWN OF LEAD AZIDE L AVRAMI M. BUMS D. DOWNS...Introduction Background A. Contact Effects B. Pulsed Electric Field Measurements Experimental A. Contact Effects B. Pulsed Electric Fields Discussion...B. Pulsed Electric Field Measurements The application of pulsed electric fields to lead azide does not exactly simulate the conditions experienced

  10. Pulsed Electric Field treatment of packaged food

    NARCIS (Netherlands)

    Roodenburg, B.

    2011-01-01

    Food manufacturers are looking for new preservation techniques that don’t influence the fresh-like characteristics of products. Non-thermal pasteurisation of food with Pulsed Electric Fields (often referred to as PEF) is an emerging technology, where the change of the food is less than with thermal

  11. Biofouling prevention with pulsed electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Ghazala, A.; Schoenbach, K.H.

    2000-02-01

    Temporary immobilization of aquatic nuisance species through application of short electric pulses has been explored as a method to prevent biofouling in cooling water systems where untreated lake, river, or sea water is used. In laboratory experiments, electrical pulses with amplitudes on the order of kilovolts/centimeter and submicrosecond duration were found to be most effective in stunning time in a temporal range from minutes to hours. The temporary immobilization is assumed to be caused by reversible membrane breakdown. This assumption is supported by results of measurements of the energy required for stunning. Based on the data obtained in laboratory experiments, field experiments in a tidal water environment have been performed. The flow velocity was such that the residence time of the aquatic nuisance species in the system was approximately half a minute. The results showed that the pulsed electric field method provides full protection against biofouling when pulses of 0.77 {micro}s width and 6 kV/cm amplitude are applied to the water at the inlet of such a cooling water system. Even at amplitudes of 1 kV/cm, the protection is still in the 90% range, at an energy expenditure of 1 kWh for the treatment of 60,000 gallons of water.

  12. Pulsed light and pulsed electric field for foods and eggs.

    Science.gov (United States)

    Dunn, J

    1996-09-01

    Two new technologies for use in the food industry are described. The first method discussed uses intense pulse of light. This pulsed light (PureBright) process uses short duration flashes of broad spectrum "white" light to kill all exposed microorganisms, including vegetative bacteria, microbial and fungal spores, viruses, and protozoan oocysts. Each pulse, or flash, of light lasts only a few hundred millionths of a second (i.e., a few hundred microseconds). The intensity of each flash of light is about 20,000 times the intensity of sunlight at the earth's surface. The flashes are typically applied at a rate of about one to tens of flashes per second. For most applications, a few flashes applied in a fraction of a second provide an effective treatment. High microbial kill can be achieved, for example, on the surfaces of packaging materials, on packaging and processing equipment, foods, and medical devices as well as on many other surfaces. In addition, some bulk materials such as water and air that allow penetration of the light can be sterilized. The results of tests to measure the effects of pulsed light on Salmonella enteritiditis on eggs are presented. The second method discussed uses multiple, short duration, high intensity electric field pulses to kill vegetative microorganisms in pumpable products. This pulsed electric field (or CoolPure) process can be applied at modest temperatures at which no appreciable thermal damage occurs and the original taste, color, texture, and functionality of products can be retained.

  13. Pulsed electric field assisted assembly of polyaniline

    Science.gov (United States)

    Kumar, Arun; Kazmer, David O.; Barry, Carol M. F.; Mead, Joey L.

    2012-08-01

    Assembling conducting polyaniline (PANi) on pre-patterned nano-structures by a high rate, commercially viable route offers an opportunity for manufacturing devices with nanoscale features. In this work we report for the first time the use of pulsed electric field to assist electrophoresis for the assembly of conducting polyaniline on gold nanowire interdigitated templates. This technique offers dynamic control over heat build-up, which has been a main drawback in the DC electrophoresis and AC dielectrophoresis as well as the main cause of nanowire template damage. The use of this technique allowed higher voltages to be applied, resulting in shorter assembly times (e.g., 17.4 s, assembly resolution of 100 nm). Moreover, the area coverage increases with the increase in number of pulses. A similar trend was observed with the deposition height and the increase in deposition height followed a linear trend with a correlation coefficient of 0.95. When the experimental mass deposited was compared with Hamaker’s theoretical model, the two were found to be very close. The pre-patterned templates with PANi deposition were subsequently used to transfer the nanoscale assembled PANi from the rigid templates to thermoplastic polyurethane using the thermoforming process.

  14. The effect of pulsed electric fields on carotenoids bioaccessibility

    NARCIS (Netherlands)

    Bot, Francesca; Verkerk, Ruud; Mastwijk, Hennie; Anese, Monica; Fogliano, Vincenzo; Capuano, Edoardo

    2018-01-01

    Tomato fractions were subjected to pulsed electric fields treatment combined or not with heating. Results showed that pulsed electric fields and heating applied in combination or individually induced permeabilization of cell membranes in the tomato fractions. However, no changes in β-carotene and

  15. Critical electric field strengths of onion tissues treated by pulsed electric fields.

    Science.gov (United States)

    Asavasanti, Suvaluk; Ersus, Seda; Ristenpart, William; Stroeve, Pieter; Barrett, Diane M

    2010-09-01

    The impact of pulsed electric fields (PEF) on cellular integrity and texture of Ranchero and Sabroso onions (Allium cepa L.) was investigated. Electrical properties, ion leakage rate, texture, and amount of enzymatically formed pyruvate were measured before and after PEF treatment for a range of applied field strengths and number of pulses. Critical electric field strengths or thresholds (E(c)) necessary to initiate membrane rupture were different because dissimilar properties were measured. Measurement of electrical characteristics was the most sensitive method and was used to detect the early stage of plasma membrane breakdown, while pyruvate formation by the enzyme alliinase was used to identify tonoplast membrane breakdown. Our results for 100-μs pulses indicate that breakdown of the plasma membrane occurs above E(c)= 67 V/cm for 10 pulses, but breakdown of the tonoplast membrane is above either E(c)= 200 V/cm for 10 pulses or 133 V/cm for 100 pulses. This disparity in field strength suggests there may be 2 critical electrical field strengths: a lower field strength for plasma membrane breakdown and a higher field strength for tonoplast membrane breakdown. Both critical electric field strengths depended on the number of pulses applied. Application of a single pulse at an electric field up to 333 V/cm had no observable effect on any measured properties, while significant differences were observed for n≥10. The minimum electric field strength required to cause a measurable property change decreased with the number of pulses. The results also suggest that PEF treatment may be more efficient if a higher electric field strength is applied for a fewer pulses.

  16. [Mechanism of ablation with nanosecond pulsed electric field].

    Science.gov (United States)

    Cen, Chao; Chen, Xin-hua; Zheng, Shu-sen

    2015-11-01

    Nanosecond pulsed electric field ablation has been widely applied in clinical cancer treatment, while its molecular mechanism is still unclear. Researchers have revealed that nanosecond pulsed electric field generates nanopores in plasma membrane, leading to a rapid influx of Ca²⁺; it has specific effect on intracellular organelle membranes, resulting in endoplasmic reticulum injuries and mitochondrial membrane potential changes. In addition, it may also change cellular morphology through damage of cytoskeleton. This article reviews the recent research advances on the molecular mechanism of cell membrane and organelle changes induced by nanosecond pulsed electric field ablation.

  17. Orientation of the agarose gel matrix in pulsed electric fields.

    OpenAIRE

    Stellwagen, J; Stellwagen, N C

    1989-01-01

    The technique of transient electric birefringence was used to investigate the effect of pulsed electric fields on the orientation of the agarose gel matrix. Orientation of the gel was observed at all electric field strengths. Very slow, time-dependent effects were observed when pulses of 10-100 V/cm were applied to 1% gels for 0.5-2 seconds, indicating that domains of the matrix were being oriented by the electric field. The sign of the birefringence reversed when the direction of the applied...

  18. Dielectric Fluid in Inhomogeneous Pulsed Electric Field

    CERN Document Server

    Shneider, M N

    2013-01-01

    We consider the dynamics of a compressible fluid under the influence of electrostrictive ponderomotive forces in strong inhomogeneous nonstationary electric fields. It is shown that if the fronts of the voltage rise at a sharp, needle-like electrode are rather steep (less than or about nanoseconds), and the region of negative pressure arises, which can reach values at which the fluid loses its continuity with the formation of cavitation ruptures. If the voltage on the electrode is not large enough or the front is flatter, the cavitation in the liquid does not occur. However, a sudden shutdown of the field results in a reverse flow of liquid from the electrode, which leads to appearance of negative pressure, and, possibly, cavitation.

  19. Skin Rejuvenation with Non-Invasive Pulsed Electric Fields

    Science.gov (United States)

    Golberg, Alexander; Khan, Saiqa; Belov, Vasily; Quinn, Kyle P.; Albadawi, Hassan; Felix Broelsch, G.; Watkins, Michael T.; Georgakoudi, Irene; Papisov, Mikhail; Mihm, Martin C., Jr.; Austen, William G., Jr.; Yarmush, Martin L.

    2015-05-01

    Degenerative skin diseases affect one third of individuals over the age of sixty. Current therapies use various physical and chemical methods to rejuvenate skin; but since the therapies affect many tissue components including cells and extracellular matrix, they may also induce significant side effects, such as scarring. Here we report on a new, non-invasive, non-thermal technique to rejuvenate skin with pulsed electric fields. The fields destroy cells while simultaneously completely preserving the extracellular matrix architecture and releasing multiple growth factors locally that induce new cells and tissue growth. We have identified the specific pulsed electric field parameters in rats that lead to prominent proliferation of the epidermis, formation of microvasculature, and secretion of new collagen at treated areas without scarring. Our results suggest that pulsed electric fields can improve skin function and thus can potentially serve as a novel non-invasive skin therapy for multiple degenerative skin diseases.

  20. Pulsed electric field reduces the permeability of potato cell wall.

    Science.gov (United States)

    Galindo, Federico Gómez; Vernier, P Thomas; Dejmek, Petr; Vicente, António; Gundersen, Martin A

    2008-05-01

    The effect of the application of pulsed electric fields to potato tissue on the diffusion of the fluorescent dye FM1-43 through the cell wall was studied. Potato tissue was subjected to field strengths ranging from 30 to 500 V/cm, with one 1 ms rectangular pulse, before application of FM1-43 and microscopic examination. Our results show a slower diffusion of FM1-43 in the electropulsed tissue when compared with that in the non-pulsed tissue, suggesting that the electric field decreased the cell wall permeability. This is a fast response that is already detected within 30 s after the delivery of the electric field. This response was mimicked by exogenous H2O2 and blocked by sodium azide, an inhibitor of the production of H2O2 by peroxidases. (c) 2007 Wiley-Liss, Inc.

  1. Effects of pulsed electric field on ULQ and RFP plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, M. [Iwate Univ., Morioka (Japan). Faculty of Engineering; Saito, K.; Suzuki, T. [and others

    1997-12-31

    Dynamo activity and self-organization processes are investigated using the application of pulsed poloidal and toroidal electric fields on ULQ and RFP plasmas. Synchronized to the application of the pulsed electric fields, the remarkable responses of the several plasma parameters are observed. The plasma has a preferential magnetic field structure, and the external perturbation activates fluctuation to maintain the structure through dynamo effect. This process changes the total dissipation with the variation of magnetic helicity in the system, showing that self organization accompanies an enhanced dissipation. (author)

  2. Production of pulsed electric fields using capacitively coupled electrodes

    Science.gov (United States)

    Kendall, B. R. F.; Schwab, F. A. S.

    1980-01-01

    It is shown that pulsed electric fields can be produced over extended volumes by taking advantage of the internal capacitances in a stacked array of electrodes. The design, construction, and performance of practical arrays are discussed. The prototype arrays involved fields of 100-1000 V/cm extending over several centimeters. Scaling to larger physical dimensions is straightforward.

  3. Review of the Dynamics of Coalescence and Demulsification by High-Voltage Pulsed Electric Fields

    OpenAIRE

    Ye Peng; Tao Liu; Haifeng Gong; Xianming Zhang

    2016-01-01

    The coalescence of droplets in oil can be implemented rapidly by high-voltage pulse electric field, which is an effective demulsification dehydration technological method. At present, it is widely believed that the main reason of pulse electric field promoting droplets coalescence is the dipole coalescence and oscillation coalescence in pulse electric field, and the optimal coalescence pulse electric field parameters exist. Around the above content, the dynamics of high-voltage pulse electric...

  4. Pulsed electric field (PEF)research at USDA, ARS, ERRC

    Science.gov (United States)

    This article summarizes the effects of pulsed electric fields on the microbiological safety and quality aspects of various liquid food matrices, obtained at USDA, ARS, Eastern Regional Research Center under CRIS Project No. 1935-41420-013-00D, Processing Intervention Technologies for Enhancing the S...

  5. Pulsed electric field processing for fruit and vegetables

    Science.gov (United States)

    This month’s column reviews the theory and current applications of pulsed electric field (PEF) processing for fruits and vegetables to improve their safety and quality. This month’s column coauthor, Stefan Toepfl, is advanced research manager at the German Institute of Food Technologies and professo...

  6. Wave packet dynamics under effect of a pulsed electric field

    Science.gov (United States)

    da Silva, A. R. C. B.; de Moura, F. A. B. F.; Dias, W. S.

    2016-06-01

    We studied the dynamics of an electron in a crystalline one-dimensional model under effect of a time-dependent Gaussian field. The time evolution of an initially Gaussian wave packet it was obtained through the numerical solution of the time-dependent Schrödinger equation. Our analysis consists of computing the electronic centroid as well as the mean square displacement. We observe that the electrical pulse is able to promote a special kind of displacement along the chain. We demonstrated a direct relation between the group velocity of the wave packet and the applied electrical pulses. We compare those numerical calculations with a semi-classical approach.

  7. Nanosecond pulsed electric field ablation of hepatocellular carcinoma.

    Science.gov (United States)

    Beebe, Stephen J; Chen, Xinhua; Liu, Jie A; Schoenbach, Karl H

    2011-01-01

    Hepatocellular carcinoma often evades effective therapy and recurrences are frequent. Recently, nanosecond pulsed electric field (nsPEF) ablation using pulse power technology has emerged as a local-regional, non-thermal, and non-drug therapy for skin cancers. In the studies reported here we use nsPEFs to ablate murine, rat and human HCCs in vitro and an ectopic murine Hepa 1-6 HCC in vivo. Using pulses with 60 or 300 ns and electric fields as high as 60 kV/cm, murine Hepa 1-6, rat N1S1 and human HepG2 HCC are readily eliminated with changes in caspase-3 activity. Interestingly caspase activities increase in the mouse and human model and decrease in the rat model as electric field strengths are increased. In vivo, while sham treated control mice survived an average of 15 days after injection and before humane euthanasia, Hepa 1-6 tumors were eliminated for longer than 50 days with 3 treatments using one hundred pulses with 100 ns at 55 kV/cm. Survival was 40% in mice treated with 30 ns pulses at 55 kV/cm. This study demonstrates that nsPEF ablation is not limited to effectively treating skin cancers and provides a rationale for treating orthotopic hepatocellular carcinoma in pre-clinical applications and ultimately in clinical trials.

  8. Pulsed electric fields (PEF applications on wine production: A review

    Directory of Open Access Journals (Sweden)

    Ozturk Burcu

    2017-01-01

    Full Text Available Novel techniques have been searched in the last decades as a result of increasing demand for high quality food products. Non-thermal processing technologies, such as pulsed electric fields (PEF have been improved to achieve inhibition of deleterious effects on quality-related compounds. The working principle of PEF is based on the application of pulses of high voltage (typically above 20 kV/cm up to 70 kV/cm to liquid foods placed between two electrodes. Pulsed electric fields technique has also been studied in winemaking process. Certain positive influences of PEF on vinification have been reported as elimination of pathogenic microorganisms, reduction of maceration time, increase in phenolic compounds extraction , acceleration of wine aging and inactivation of oxidative enzymes. The aim of this review is to summarize the potential applications of PEF in winemaking and to express its effects on quality of wine.

  9. Transient electrical field across cellular membranes: pulsed electric field treatment of microbial cells

    Energy Technology Data Exchange (ETDEWEB)

    Timoshkin, I V [High Voltage Technologies Group, Institute for Energy and Environment, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW (United Kingdom); MacGregor, S J [High Voltage Technologies Group, Institute for Energy and Environment, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW (United Kingdom); Fouracre, R A [High Voltage Technologies Group, Institute for Energy and Environment, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW (United Kingdom); Crichton, B H [High Voltage Technologies Group, Institute for Energy and Environment, Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW (United Kingdom); Anderson, J G [Robertson Trust Laboratory for Electronic Sterilization Technologies (ROLEST), Department of Electronic and Electrical Engineering, University of Strathclyde, 204 George Street, Glasgow, G1 1XW (United Kingdom)

    2006-02-07

    The pulsed electric field (PEF) treatment of liquid and pumpable products contaminated with microorganisms has attracted significant interest from the pulsed power and bioscience research communities particularly because the inactivation mechanism is non-thermal, thereby allowing retention of the original nutritional and flavour characteristics of the product. Although the biological effects of PEF have been studied for several decades, the physical mechanisms of the interaction of the fields with microorganisms is still not fully understood. The present work is a study of the dynamics of the electrical field both in a PEF treatment chamber with dielectric barriers and in the plasma (cell) membrane of a microbial cell. It is shown that the transient process can be divided into three physical phases, and models for these phases are proposed and briefly discussed. The complete dynamics of the time development of the electric field in a spherical dielectric shell representing the cellular membrane is then obtained using an analytical solution of the Ohmic conduction problem. It was found that the field in the membrane reaches a maximum value that could be two orders of magnitude higher than the original Laplacian electrical field in the chamber, and this value was attained in a time comparable to the field relaxation time in the chamber. Thus, the optimal duration of the field during PEF treatment should be equal to such a time.

  10. Relaxation Dynamics of Ferroelectric Liquid Crystals in Pulsed Electric Field

    Science.gov (United States)

    Kudreyko, A. A.; Migranov, N. G.; Migranova, D. N.

    2016-11-01

    In this contribution we report a theoretical study of relaxation processes in surface-stabilized ferroelectric liquid crystals with spontaneous polarization. The influence of pulsed electric field on the behavior of ferroelectric liquid crystal in the SmC* phase, which is placed in a thin cell with strong anchoring of SmC* molecules with the boundary substrate, is studied. In the vicinity of the substrate interface, temporal dependence of the azimuthal motion of the director induced by electric field is obtained. The response to the external distortion of ferroelectric liquid crystal confined between two microstructured substrates is the occurrence of periodic temporal formation of solitons connected with the distortion of the director field n in the sample bulk. The interplay between microstructured substrates and director distribution of the ferroelectric SmC* phase is explained by the Frenkel-Kontorova model for a chain of atoms, but adapted for the continuum problem.

  11. Effects of pulsed electrical field processing on microbial survival, quality change and nutritional characteristics of blueberries

    Science.gov (United States)

    Whole fresh blueberries were treated using a parallel pulsed electric field (PEF) treatment chamber and a sanitizer solution (60 ppm peracetic acid [PAA]) as PEF treatment medium with square wave bipolar pulses at 2 kV/cm electric field strength, 1us pulse width, and 100 pulses per second for 2, 4, ...

  12. Analysis of circular wave packets generated by pulsed electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, S., E-mail: shuhei@concord.itp.tuwien.ac.at [Institute for Theoretical Physics, Vienna University of Technology, Vienna (Austria); Reinhold, C.O. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States); Department of Physics, University of Tennessee, Knoxville, TN 37996 (United States); Burgdoerfer, J. [Institute for Theoretical Physics, Vienna University of Technology, Vienna (Austria); Department of Physics, University of Tennessee, Knoxville, TN 37996 (United States); Wyker, B.; Ye, S.; Dunning, F.B. [Department of Physics and Astronomy and the Rice Quantum Institute, Rice University, Houston, TX 77005-1892 (United States)

    2012-05-15

    We demonstrate that circular wave packets in high Rydberg states generated by a pulsed electric field applied to extreme Stark states are characterized by a position-dependent energy gradient that leads to a correlation between the principal quantum number n and the spatial coordinate. This correlation is rather insensitive to the initial state and can be seen even in an incoherent mix of states such as is generated experimentally allowing information to be placed into, and extracted from, such wave packets. We show that detailed information on the spatial distribution of a circular wave packet can be extracted by analyzing the complex phase of its expansion coefficients.

  13. Analysis of Circular Wave Packets Generated by Pulsed Electric Fields

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, S. [Vienna University of Technology, Austria; Reinhold, Carlos O [ORNL; Burgdorfer, J. [Vienna University of Technology, Austria; Wyker, B. [Rice University; Ye, S. [Rice University; Dunning, F. B. [Rice University

    2011-01-01

    We demonstrate that circular wave packets in high Rydberg states generated using a pulsed electric field applied to extreme Stark states are characterized by a position-dependent energy gradient that leads to a correlation between the principal quantum number n and the spatial coordinate. This correlation is rather insensitive to the initial state and can be seen even in an incoherent mix of states such as is generated experimentally allowing information to be placed into, and extracted from, such wavepackets. We show that detailed information on the spatial distribution of a circular wave packet can be extracted by analyzing the complex phase of its expansion coefficient.

  14. The effect of pulsed electric fields on carotenoids bioaccessibility: The role of tomato matrix.

    Science.gov (United States)

    Bot, Francesca; Verkerk, Ruud; Mastwijk, Hennie; Anese, Monica; Fogliano, Vincenzo; Capuano, Edoardo

    2018-02-01

    Tomato fractions were subjected to pulsed electric fields treatment combined or not with heating. Results showed that pulsed electric fields and heating applied in combination or individually induced permeabilization of cell membranes in the tomato fractions. However, no changes in β-carotene and lycopene bioaccessibility were found upon combined and individual pulsed electric fields and heating, except in the following cases: (i) in tissue, a significant decrease in lycopene bioaccessibility upon combined pulsed electric fields and heating and heating only was observed; (ii) in chromoplasts, both β-carotene and lycopene bioaccessibility significantly decreased upon combined pulsed electric fields and heating and pulsed electric fields only. The reduction in carotenoids bioaccessibility was attributed to modification in chromoplasts membrane and carotenoids-protein complexes. Differences in the effects of pulsed electric fields on bioaccessibility among different tomato fractions were related to tomato structure complexity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. [Research advances of anti-tumor immune response induced by pulse electric field ablation].

    Science.gov (United States)

    Cui, Guang-ying; Diao, Hong-yan

    2015-11-01

    As a novel tumor therapy, pulse electric field has shown a clinical perspective. This paper reviews the characteristics of tumor ablation by microsecond pulse and nanosecond pulse electric field, and the research advances of anti-tumor immune response induced by pulse electric field ablation. Recent researches indicate that the pulse electric field not only leads to a complete ablation of local tumor, but also stimulates a protective immune response, thereby inhibiting tumor recurrence and metastasis. These unique advantages will show an extensive clinical application in the future. However, the mechanism of anti-tumor immune response and the development of related tumor vaccine need further studies.

  16. Effects of pulsed electric fields on inactivation kinetics of Listeria innocua

    NARCIS (Netherlands)

    Wouters, P.C.; Dutreux, N.; Smelt, J.P.P.M.; Lelieveld, H.L.M.

    1999-01-01

    The effects of pulsed electric field (PEF) treatment and processing factors on the inactivation kinetics of Listeria innocua NCTC 11289 were investigated by using a pilot plant PEF unit with a flow rate of 200 liters/h. The electric field strength, pulse length, number of pulses, and inlet temperatu

  17. Review of the Dynamics of Coalescence and Demulsification by High-Voltage Pulsed Electric Fields

    Directory of Open Access Journals (Sweden)

    Ye Peng

    2016-01-01

    Full Text Available The coalescence of droplets in oil can be implemented rapidly by high-voltage pulse electric field, which is an effective demulsification dehydration technological method. At present, it is widely believed that the main reason of pulse electric field promoting droplets coalescence is the dipole coalescence and oscillation coalescence in pulse electric field, and the optimal coalescence pulse electric field parameters exist. Around the above content, the dynamics of high-voltage pulse electric field promoting the coalescence of emulsified droplets is studied by researchers domestically and abroad. By review, the progress of high-voltage pulse electric field demulsification technology can get a better understanding, which has an effect of throwing a sprat to catch a whale on promoting the industrial application.

  18. A new pulsed electric field microreactor: comparison between the laboratory and microtechnology scale

    NARCIS (Netherlands)

    Fox, Martijn; Esveld, Erik; Luttge, Regina; Boom, Remko

    2005-01-01

    This paper presents a new microreactor dedicated for pulsed electric field treatment (PEF), which is a pasteurization method that inactivates microorganisms with short electric pulses. The PEF microreactor consists of a flow-through channel with a constriction where the electric field is focussed. C

  19. Improving carotenoid extraction from tomato waste by pulsed electric fields.

    Directory of Open Access Journals (Sweden)

    Elisa eLuengo

    2014-08-01

    Full Text Available In this investigation, the influence of the application of Pulsed Electric Fields (PEF of different intensities (3-7 kV/cm and 0-300 μs on the carotenoid extraction from tomato peel and pulp in a mixture of hexane:acetone:ethanol was studied with the aim of increasing extraction yield or reducing the percentage of the less green solvents in the extraction medium. According to the cellular disintegration index, the optimum treatment time for the permeabilization of tomato peel and pulp at different electric field strengths was 90 µs. The PEF permeabilization of tomato pulp did not significantly increase the carotenoid extraction. However, a PEF-treatment at 5 kV/cm improved the carotenoid extraction from tomato peel by 39 % as compared with the control in a mixture of hexane:ethanol:acetone (50:25:25. Further increments of electric field from 5 to 7 kV/cm did not increase significantly the extraction of carotenoids. . The presence of acetone in the solvent mixture did not positively affect the carotenoid extraction when the tomato peels were PEF-treated. Response surface methodology was used to determine the potential of PEF for reducing the percentage of hexane in a hexane:ethanol mixture. The application of a PEF-treatment allowed reducing the hexane percentage from 45 to 30 % without affecting the carotenoid extraction yield. The antioxidant capacity of the extracts obtained from tomato peel was correlated with the carotenoid concentration and it was not affected by the PEF-treatment.

  20. Pulsed electric field technology: Modeling of electric field and temperature distributions within continuous flow PEF treatment chamber

    OpenAIRE

    Salengke, dkk

    2012-01-01

    Innovations and technology developments in the field of food pasteurization and sterilization are continuously evolving. These include innovations in thermal processing technologies such as aseptic processing, ohmic technology, and microwave technology, as well as non-thermal processing technologies which include pulsed electric field technology and high pressure processing technology. This paper discussed the results of a study on mathematical modeling of electric field and temperature distr...

  1. [Research progress of nanosecond pulsed electric field applied to intracellular electromanipulation].

    Science.gov (United States)

    Yao, Chenguo; Mo, Dengbin; Sun, Caixin; Chen, Xin; Xiong, Zheng'ai

    2008-10-01

    In recent years, many experts have done some researches on experiment and mechanism of intracellular electromanipulation (IEM) under nanosecond pulsed electric field (nsPEF). The experiment results have shown that nsPEF could not induce electroporation of cell membrane, but could induce intracellular effects such as apoptosis, calcium release, enhancement of gene expression, and fragmentation of DNA and chromosome. In order to account for the phenomenon, researchers believe that when the pulse width of the pulsed electric field is larger than the charging time of plasma membrane, the pulsed electric field mainly targets on the outer membrane of cell; and that the effect of the pulsed electric field on nucleus and nuclear membrane increases with the decrease of the pulse width. It is also believed that the effect of electroporation changes from the outer membrane to intracellular electromanipulation when the pulse width decreases to a value being smaller than the charging time of plasma membrane.

  2. Toward 6 log10 pulsed electric field inactivation with conductive plastic packaging material

    NARCIS (Netherlands)

    Roodenburg, B.; Haan, S.W.H. de; Ferreira, J.A.; Coronel, P.; Wouters, P.C.; Hatt, V.

    2013-01-01

    Generally, high grade products such as pulsed electric field (PEF) treated fruit juices are packaged after their preservative treatment. However, PEF treatment after packaging could avoid recontamination of the product and becomes feasible when electric field pulses of sufficient magnitude can be ge

  3. Toward 6 log10 pulsed electric field inactivation with conductive plastic packaging material

    NARCIS (Netherlands)

    Roodenburg, B.; Haan, S.W.H. de; Ferreira, J.A.; Coronel, P.; Wouters, P.C.; Hatt, V.

    2013-01-01

    Generally, high grade products such as pulsed electric field (PEF) treated fruit juices are packaged after their preservative treatment. However, PEF treatment after packaging could avoid recontamination of the product and becomes feasible when electric field pulses of sufficient magnitude can be

  4. Commercial scale pulsed electric field processing of tomato juice.

    Science.gov (United States)

    Min, Seacheol; Jin, Z Tony; Zhang, Q Howard

    2003-05-21

    Effects of commercial scale pulsed electric field (PEF) processing on the quality of tomato juice were studied and compared with those of thermal processing. Tomato juice was prepared by hot break at 88 degrees C for 2 min or by cold break at 68 degrees C for 2 min and then thermally processed at 92 degrees C for 90 s or PEF processed at 40 kV/cm for 57 micros. Thermally processed, PEF processed, and unprocessed control juices were packed into 50 mL sterilized polypropylene tubes in a sanitary glovebox and stored at 4 degrees C for 112 days. Both thermally and PEF processed juices showed microbial shelf life at 4 degrees C for 112 days. The lipoxygenase activities of thermally and PEF processed juices were 0 and 47%, respectively. PEF processed juice retained more ascorbic acid than thermally processed juice at 4 degrees C for 42 days (p Brix, pH, or viscosity between thermally and PEF processed juices during the storage (p > 0.05). Sensory evaluations indicated that flavor and overall acceptability of PEF processed juice were preferred to those of thermally processed juice (p < 0.05).

  5. High Dynamic Range Electric Field Sensor for Electromagnetic Pulse Detection

    CERN Document Server

    Lin, Che-Yun; Lee, Beom Suk; Zhang, Xingyu; Chen, Ray T

    2014-01-01

    We design a high dynamic range electric field sensor based on domain inverted electro-optic (E-O) polymer Y-fed directional coupler for electromagnetic wave detection. This electrode-less, all optical, wideband electrical field sensor is fabricated using standard processing for E-O polymer photonic devices. Experimental results demonstrate effective detection of electric field from 16.7V/m to 750KV/m at a frequency of 1GHz, and spurious free measurement range of 70dB.

  6. Electric field measurements in a nanosecond pulse discharge in atmospheric air

    Science.gov (United States)

    Simeni Simeni, Marien; Goldberg, Benjamin M.; Zhang, Cheng; Frederickson, Kraig; Lempert, Walter R.; Adamovich, Igor V.

    2017-05-01

    The paper presents the results of temporally and spatially resolved electric field measurements in a nanosecond pulse discharge in atmospheric air, sustained between a razor edge high-voltage electrode and a plane grounded electrode covered by a thin dielectric plate. The electric field is measured by picosecond four-wave mixing in a collinear phase-matching geometry, with time resolution of approximately 2 ns, using an absolute calibration provided by measurements of a known electrostatic electric field. The results demonstrate electric field offset on the discharge center plane before the discharge pulse due to surface charge accumulation on the dielectric from the weaker, opposite polarity pre-pulse. During the discharge pulse, the electric field follows the applied voltage until ‘forward’ breakdown occurs, after which the field in the plasma is significantly reduced due to charge separation. When the applied voltage is reduced, the field in the plasma reverses direction and increases again, until the weak ‘reverse’ breakdown occurs, producing a secondary transient reduction in the electric field. After the pulse, the field is gradually reduced on a microsecond time scale, likely due to residual surface charge neutralization by transport of opposite polarity charges from the plasma. Spatially resolved electric field measurements show that the discharge develops as a surface ionization wave. Significant surface charge accumulation on the dielectric surface is detected near the end of the discharge pulse. Spatially resolved measurements of electric field vector components demonstrate that the vertical electric field in the surface ionization wave peaks ahead of the horizontal electric field. Behind the wave, the vertical field remains low, near the detection limit, while the horizontal field is gradually reduced to near the detection limit at the discharge center plane. These results are consistent with time-resolved measurements of electric field

  7. Comparison of pulsed corona plasma and pulsed electric fields for the decontamination of water containing Legionella pneumophila as model organism.

    Science.gov (United States)

    Banaschik, Robert; Burchhardt, Gerhard; Zocher, Katja; Hammerschmidt, Sven; Kolb, Juergen F; Weltmann, Klaus-Dieter

    2016-12-01

    Pulsed corona plasma and pulsed electric fields were assessed for their capacity to kill Legionella pneumophila in water. Electrical parameters such as in particular dissipated energy were equal for both treatments. This was accomplished by changing the polarity of the applied high voltage pulses in a coaxial electrode geometry resulting in the generation of corona plasma or an electric field. For corona plasma, generated by high voltage pulses with peak voltages of +80kV, Legionella were completely killed, corresponding to a log-reduction of 5.4 (CFU/ml) after a treatment time of 12.5min. For the application of pulsed electric fields from peak voltages of -80kV a survival of log 2.54 (CFU/ml) was still detectable after this treatment time. Scanning electron microscopy images of L. pneumophila showed rupture of cells after plasma treatment. In contrast, the morphology of bacteria seems to be intact after application of pulsed electric fields. The more efficient killing for the same energy input observed for pulsed corona plasma is likely due to induced chemical processes and the generation of reactive species as indicated by the evolution of hydrogen peroxide. This suggests that the higher efficacy and efficiency of pulsed corona plasma is primarily associated with the combined effect of the applied electric fields and the promoted reaction chemistry.

  8. Campo elétrico pulsado Pulsed electric field

    Directory of Open Access Journals (Sweden)

    Mirella Lima Binoti

    2012-05-01

    Full Text Available Campos elétricos pulsados de alta intensidade (CEPAI constituem um método não-térmico de conservação para alimentos em substituição à pasteurização tradicional. Em comparação ao processamento térmico, os CEPAI, além de serem eficientes na eliminação de micro-organismos e na inativação de enzimas, também minimizam as perdas de sabor, cor, textura, nutrientes e componentes termolábeis dos alimentos. O objetivo desse trabalho foi levantar dados bibliográficos atuais sobre o tema CEPAI, abordando: definição do processo, instalação experimental, efeito da ruptura dielétrica do alimento, efeito sobre micro-organismo, enzimas e constituintes dos alimentos. Os dados encontrados na literatura apontam o tratamento por CEPAI como alternativa promissora para a conservação de alimentos, podendo ser utilizado como tecnologia única ou como complemento aos processamentos térmicos.Pulsed electric fields of high intensity (HIPEF is a non-thermal food conservation to replace traditional thermal pasteurization. Compared to thermal processing, the HIPEF as well as being effective in removing microorganisms and inactivate enzymes also minimize the loss of flavor, color, texture, nutrients and labile components of food. The aim of this work was to gather bibliographic data current HIPEF on the subject, covering: experimental setup, effects of dielectric breakdown of food, effect on microorganisms, enzymes and constituents of food. The data found in the literature indicate treatment of HIPEF as a promising alternative for food conservation and it could be used as a single technology or in addition to thermal processing.

  9. Pulsed electric field processing of egg products: a review.

    Science.gov (United States)

    Yogesh, K

    2016-02-01

    Thermal processing ensures safety and enhances the shelf-life of most of the food products. It alters the structural-chemical composition, modifies heat labile components, as well as affects the functional properties of food products. This has driven the development of non-thermal food processing techniques, primarily for extending the shelf-life of different food products. These techniques are currently also being evaluated for their effects on product processing, quality and other safety parameters. Pulsed electric field (PEF) is an example of non-thermal technique which can be applied for a variety of purpose in the food processing industry. PEF can be used for antimicrobial treatment of various food products to improve the storability or food safety, for extraction and recovery of some high-value compounds from a food matrix or for stabilization of various food products through inactivation of some enzymes or catalysts. Research on the application of PEF to control spoilage or pathogenic microorganisms in different egg products is being currently focused. It has been reported that PEF effectively reduces the activity of various microorganisms in a variety of egg products. However, the PEF treatment also alters the structural and functional properties to some extent and there is a high degree of variability between different studies. In addition to integrating findings, the present review also provides several explanations for the inconsistency in findings between different studies related to PEF processing of egg products. Several specific recommendations for future research directions on PEF processing are well discussed in this review.

  10. Pulsed electric field assisted sol-gel preparation of TiO2 nanoparticles

    Science.gov (United States)

    Mani, Rajaboopathi; Han, Bing; Louhi-Kultanen, Marjatta

    2016-10-01

    This work studies the effect of a pulsed electric field (PEF) on the precipitation and properties of TiO2 nanoparticles. TiO2 nanoparticles were prepared using pulsed DC electric field assisted sol-gel method. The duration of the PEF treatment was varied to investigate its effect on the particle size of TiO2 nanoparticles. The nanoparticles were characterized by X-ray powder diffraction (XRD), Raman spectroscopy, UV diffuse reflectance spectroscopy (UV-DRS) and transmission electron microscopy (TEM). It was found that TiO2 particles prepared with pulsed electric field assisted sol-gel method had enhanced average crystallite size due to the effect of the pulsed electric field on primary nucleation. The effect of electric field on nanoparticle preparation is interesting which can be used to control the grain and crystallite size of nanoparticle.

  11. Nanosecond pulsed electric fields and the cell cycle

    Science.gov (United States)

    Mahlke, Megan A.

    Exposure to nanosecond pulsed electrical fields (nsPEFs) can cause poration of external and internal cell membranes, DNA damage, and disassociation of cytoskeletal components, all of which are capable of disrupting a cell's ability to replicate. The phase of the cell cycle at the time of exposure is linked to differential sensitivities to nsPEFs across cell lines, as DNA structure, membrane elasticity, and cytoskeletal structure change dramatically during the cell cycle. Additionally, nsPEFs are capable of activating cell cycle checkpoints, which could lead to apoptosis or slow population growth. NsPEFs are emerging as a method for treating tumors via apoptotic induction; therefore, investigating the relevance of nsPEFs and the cell cycle could translate into improved efficacy in tumor treatment. Populations of Jurkat and Chinese Hamster Ovary (CHO) cells were examined post-exposure (10 ns pulse trains at 150kV/cm) by analysis of DNA content via propidium iodide staining and flow cytometric analysis at various time points (1, 6, and 12h post-exposure) to determine population distribution in cell cycle phases. Additionally, CHO and Jurkat cells were synchronized in G1/S and G2/M phases, pulsed, and analyzed to evaluate the role of cell cycle phase in survival of nsPEFs. CHO populations appeared similar to sham populations post-nsPEFs but exhibited arrest in the G1 phase at 6h after exposure. Jurkat cells exhibited increased cell death after nsPEFs compared to CHO cells but did not exhibit checkpoint arrest at any observed time point. The G1/S phase checkpoint is partially controlled by the action of p53; the lack of an active p53 response in Jurkat cells could contribute to their ability to pass this checkpoint and resist cell cycle arrest. Both cell lines exhibited increased sensitivity to nsPEFs in G2/M phase. Live imaging of CHO cells after nsPEF exposure supports the theory of G1/S phase arrest, as a reduced number of cells undergo mitosis within 24 h when

  12. Assessment of the electrochemical effects of pulsed electric fields in a biological cell suspension.

    Science.gov (United States)

    Chafai, Djamel Eddine; Mehle, Andraž; Tilmatine, Amar; Maouche, Bachir; Miklavčič, Damijan

    2015-12-01

    Electroporation of cells is successfully used in biology, biotechnology and medicine. Practical problems still arise in the electroporation of cells in suspension. For example, the determination of cell electroporation is still a demanding and time-consuming task. Electric pulses also cause contamination of the solution by the metal released from the electrodes and create local enhancements of the electric field, leading to the occurrence of electrochemical reactions at the electrode/electrolyte interface. In our study, we investigated the possibility of assessing modifications to the cell environment caused by pulsed electric fields using electrochemical impedance spectroscopy. We designed an experimental protocol to elucidate the mechanism by which a pulsed electric field affects the electrode state in relation to different electrolyte conductivities at the interface. The results show that a pulsed electric field affects electrodes and its degree depends on the electrolyte conductivity. Evolution of the electrochemical reaction rate depends on the initial free charges and those generated by the pulsed electric field. In the presence of biological cells, the initial free charges in the medium are reduced. The electrical current path at low frequency is longer, i.e., conductivity is decreased, even in the presence of increased permeability of the cell membrane created by the pulsed electric field.

  13. Comparison of membrane electroporation and protein denature in response to pulsed electric field with different durations.

    Science.gov (United States)

    Huang, Feiran; Fang, Zhihui; Mast, Jason; Chen, Wei

    2013-05-01

    In this paper, we compared the minimum potential differences in the electroporation of membrane lipid bilayers and the denaturation of membrane proteins in response to an intensive pulsed electric field with various pulse durations. Single skeletal muscle fibers were exposed to a pulsed external electric field. The field-induced changes in the membrane integrity (leakage current) and the Na channel currents were monitored to identify the minimum electric field needed to damage the membrane lipid bilayer and the membrane proteins, respectively. We found that in response to a relatively long pulsed electric shock (longer than the membrane intrinsic time constant), a lower membrane potential was needed to electroporate the cell membrane than for denaturing the membrane proteins, while for a short pulse a higher membrane potential was needed. In other words, phospholipid bilayers are more sensitive to the electric field than the membrane proteins for a long pulsed shock, while for a short pulse the proteins become more vulnerable. We can predict that for a short or ultrashort pulsed electric shock, the minimum membrane potential required to start to denature the protein functions in the cell plasma membrane is lower than that which starts to reduce the membrane integrity.

  14. Pulsed and streamer discharges in air above breakdown electric field

    NARCIS (Netherlands)

    Sun, A.B.; Teunissen, H.J.; Ebert, U.

    2013-01-01

    A 3D particle model is developed to investigate the streamer formation in electric fields above the breakdown threshold, in atmospheric air (1bar, 300 Kelvin). Adaptive particle management, adaptive mesh refinement and parallel computing techniques are used in the code. Photoionization and electron

  15. Shaped pulse electric-field construction and interferometric characterization: The SPECIFIC method

    CERN Document Server

    Coughlan, Matthew A; Weber, Stefan M; Bowlan, Pamela; Trebino, Rick; Levis, Robert J

    2009-01-01

    A method is reported for creating, generating, and measuring parametrically shaped pulses for time-bandwidth product >>5, which consists of a parametric pulse-shaping algorithm, a spatial light modulation system and a single shot interferometric characterization scheme (SEA TADPOLE) . The utilization of these tools marks the inception of a new method called SPECIFIC, shaped-pulse electric-field construction and interferometric characterization, capable of producing complex shaped laser pulses for coherent control experiments.

  16. Transient features in nanosecond pulsed electric fields differentially modulate mitochondria and viability.

    Directory of Open Access Journals (Sweden)

    Stephen J Beebe

    Full Text Available It is hypothesized that high frequency components of nanosecond pulsed electric fields (nsPEFs, determined by transient pulse features, are important for maximizing electric field interactions with intracellular structures. For monopolar square wave pulses, these transient features are determined by the rapid rise and fall of the pulsed electric fields. To determine effects on mitochondria membranes and plasma membranes, N1-S1 hepatocellular carcinoma cells were exposed to single 600 ns pulses with varying electric fields (0-80 kV/cm and short (15 ns or long (150 ns rise and fall times. Plasma membrane effects were evaluated using Fluo-4 to determine calcium influx, the only measurable source of increases in intracellular calcium. Mitochondria membrane effects were evaluated using tetramethylrhodamine ethyl ester (TMRE to determine mitochondria membrane potentials (ΔΨm. Single pulses with short rise and fall times caused electric field-dependent increases in calcium influx, dissipation of ΔΨm and cell death. Pulses with long rise and fall times exhibited electric field-dependent increases in calcium influx, but diminished effects on dissipation of ΔΨm and viability. Results indicate that high frequency components have significant differential impact on mitochondria membranes, which determines cell death, but lesser variances on plasma membranes, which allows calcium influxes, a primary determinant for dissipation of ΔΨm and cell death.

  17. Transient features in nanosecond pulsed electric fields differentially modulate mitochondria and viability.

    Science.gov (United States)

    Beebe, Stephen J; Chen, Yeong-Jer; Sain, Nova M; Schoenbach, Karl H; Xiao, Shu

    2012-01-01

    It is hypothesized that high frequency components of nanosecond pulsed electric fields (nsPEFs), determined by transient pulse features, are important for maximizing electric field interactions with intracellular structures. For monopolar square wave pulses, these transient features are determined by the rapid rise and fall of the pulsed electric fields. To determine effects on mitochondria membranes and plasma membranes, N1-S1 hepatocellular carcinoma cells were exposed to single 600 ns pulses with varying electric fields (0-80 kV/cm) and short (15 ns) or long (150 ns) rise and fall times. Plasma membrane effects were evaluated using Fluo-4 to determine calcium influx, the only measurable source of increases in intracellular calcium. Mitochondria membrane effects were evaluated using tetramethylrhodamine ethyl ester (TMRE) to determine mitochondria membrane potentials (ΔΨm). Single pulses with short rise and fall times caused electric field-dependent increases in calcium influx, dissipation of ΔΨm and cell death. Pulses with long rise and fall times exhibited electric field-dependent increases in calcium influx, but diminished effects on dissipation of ΔΨm and viability. Results indicate that high frequency components have significant differential impact on mitochondria membranes, which determines cell death, but lesser variances on plasma membranes, which allows calcium influxes, a primary determinant for dissipation of ΔΨm and cell death.

  18. Estimating of pulsed electric fields using optical measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Flanagan, Timothy McGuire; Chantler, Gary.

    2013-09-01

    We performed optical electric field measurements ion nanosecond time scales using the electrooptic crystal beta barium borate (BBO). Tests were based on a preliminary bench top design intended to be a proofofprinciple stepping stone towards a modulardesign optical Efield diagnostic that has no metal in the interrogated environment. The long term goal is to field a modular version of the diagnostic in experiments on large scale xray source facilities, or similarly harsh environments.

  19. Electron-Positron Pair Production in Structured Pulses of Electric Fields

    CERN Document Server

    Kohlfürst, Christian

    2012-01-01

    The non-perturbative electron-positron pair production in time-dependent electric fields is investigated. The quantum kinetic formalism is employed in order to calculate the electron density for various field configurations. The corresponding set of first order, ordinary differential equations is analyzed and numerically solved. The focus of this study lies on the dynamically assisted Schwinger effect in pulsed electric fields with at least two different time scales. Furthermore, interference effects arising in setups with multiple pulses are examined and first results for an optimization of the particle number yield by pulse-shaping are given.

  20. Pasteurization of strawberry puree using a pilot plant pulsed electric fields (PEF) system

    Science.gov (United States)

    The processing of strawberry puree by pulsed electric fields (PEF) in a pilot plant system has never been evaluated. In addition, a method does not exist to validate the exact number and shape of the pulses applied during PEF processing. Both buffered peptone water (BPW) and fresh strawberry puree (...

  1. Validation of a pulsed electric field process to pasteurize strawberry puree

    Science.gov (United States)

    An inexpensive data acquisition method was developed to validate the exact number and shape of the pulses applied during pulsed electric fields (PEF) processing. The novel validation method was evaluated in conjunction with developing a pasteurization PEF process for strawberry puree. Both buffered...

  2. Cavitation in dielectric fluid in inhomogeneous pulsed electric field

    CERN Document Server

    Shneider, M N

    2013-01-01

    This paper proposes a method for studying the early stages of the cavitation development in arbitrary, non-stationary conditions. This method is based on the comparison of the results of calculations in the framework of a theoretical model of the liquid dielectrics motion in a strong non-uniform electric field and experiments with controlled parameters. This approach allows us to find the critical negative pressure, at which cavitation begins to develop, and to determine the values of the constants in the classical models of cavitation.

  3. Pulsed Direct Current Electric Fields Enhance Osteogenesis in Adipose-Derived Stromal Cells

    OpenAIRE

    Hammerick, Kyle E.; James, Aaron W.; Huang, Zubin; Prinz, Fritz B.; Michael T. Longaker

    2009-01-01

    Adipose-derived stromal cells (ASCs) constitute a promising source of cells for regenerative medicine applications. Previous studies of osteogenic potential in ASCs have focused on chemicals, growth factors, and mechanical stimuli. Citing the demonstrated role electric fields play in enhancing healing in bone fractures and defects, we investigated the ability of pulsed direct current electric fields to drive osteogenic differentiation in mouse ASCs. Employing 50 Hz direct current electric fie...

  4. Size separation of DNA molecules by pulsed electric field dielectrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Nedelcu, S [National Institute for R and D in Microtechnologies, Str. Erou Iancu Nicolae 32B, PO Box 38-160, 023573 Bucharest (Romania); Watson, J H P [School of Physics and Astronomy, University of Southampton, Highfield, SO17 1BJ, Southampton (United Kingdom)

    2004-08-07

    In this paper we propose an electrode design and a switching pattern of the applied DC electrode potentials for a microfluidic device to be used in size separation of DNA molecules. Estimates on the separation resolution, which are based on numerical solutions of a Newton-type equation on time-averaged quantities, are presented for an input batch sample of DNA fragments with sizes up to 220 base pairs (bp). The active area of the device (which can be microfabricated by standard photolitographic techniques) is a channel 6 {mu}m wide, 8 {mu}m deep and 150 {mu}m in length, flanked by 23 plane parallel integrated electrodes, individually addressed with low DC voltages, up to {+-} 25 V. In the active area a time-dependent non-uniform electric field, or a travelling dielectrophoretic wave (TDW) is being produced. In order to enhance the separation resolution, the polarization DC potentials are switched with a relatively high frequency ({approx} 10{sup -7} s), which is chosen accordingly with the buffer conductivity and dielectric constants of the fluid and particles. Since the external field is of DC type, we put forward an explanatory model of the dielectric response of the DNA to the time-dependent applied field. We then numerically investigate the size-dependent response of the DNA in a low conductivity buffer ({approx}0.01 {omega}{sup -1} m{sup -1}) under the influence of the electric field, which is calculated by means of the method of moments. The results of the computer modelling indicate the existence of a threshold value for the size of the successfully transported molecules, which can be adjusted by varying the velocity of the dielectrophoretic wave produced by the system. The estimated error in selecting a chosen group of molecules with sizes above a specified value is about 5 bp, while the processing times are of the order of hundred of seconds.

  5. [Negative air ions generated by plants upon pulsed electric field stimulation applied to soil].

    Science.gov (United States)

    Wu, Ren-ye; Deng, Chuan-yuan; Yang, Zhi-jian; Weng, Hai-yong; Zhu, Tie-jun-rong; Zheng, Jin-gui

    2015-02-01

    This paper investigated the capacity of plants (Schlumbergera truncata, Aloe vera var. chinensis, Chlorophytum comosum, Schlumbergera bridgesii, Gymnocalycium mihanovichii var. friedrichii, Aspidistra elatior, Cymbidium kanran, Echinocactus grusonii, Agave americana var. marginata, Asparagus setaceus) to generate negative air ions (NAI) under pulsed electric field stimulation. The results showed that single plant generated low amounts of NAI in natural condition. The capacity of C. comosum and G. mihanovichii var. friedrichii generated most NAI among the above ten species, with a daily average of 43 ion · cm(-3). The least one was A. americana var. marginata with the value of 19 ion · cm(-3). When proper pulsed electric field stimulation was applied to soil, the NAI of ten plant species were greatly improved. The effect of pulsed electric field u3 (average voltage over the pulse period was 2.0 x 10(4) V, pulse frequency was 1 Hz, and pulse duration was 50 ms) was the greatest. The mean NAI concentration of C. kanran was the highest 1454967 ion · cm(-3), which was 48498.9 times as much as that in natural condition. The lowest one was S. truncata with the value of 34567 ion · cm(-3), which was 843.1 times as much as that in natural condition. The capacity of the same plants to generate negative air ion varied extremely under different intensity pulsed electric fields.

  6. Electric field simulation and measurement of a pulse line ion accelerator

    Institute of Scientific and Technical Information of China (English)

    SHEN Xiao-Kang; ZHANG Zi-Min; CAO Shu-Chun; ZHAO Hong-Wei; WANG Bo; SHEN Xiao-Li; ZHAO Quan-Tang; LIU Ming; JING Yi

    2012-01-01

    An oil dielectric helical pulse line to demonstrate the principles of a Pulse Line Ion Accelerator (PL1A) has been designed and fabricated.The simulation of the axial electric field of an accelerator with CST code has been completed and the simulation results show complete agreement with the theoretical calculations.To fully understand the real value of the electric field excited from the helical line in PLIA,an optical electric integrated electric field measurement system was adopted.The measurement result shows that the real magnitude of axial electric field is smaller than that calculated,probably due to the actual pitch of the resister column which is much less than that of helix.

  7. Using electric fields for pulse compression and group velocity control

    CERN Document Server

    Li, Qian; Thuresson, Axel; Rippe, Lars; Kröll, Stefan

    2016-01-01

    In this article, we experimentally demonstrate a new way of controlling the group velocity of an optical pulse by using a combination of spectral hole burning, slow light effect and linear Stark effect in a rare-earth-ion-doped crystal. The group velocity can be changed continuously by a factor of 20 without significant pulse distortion or absorption of the pulse energy. With a similar technique, an optical pulse can also be compressed in time. Theoretical simulations were developed to simulate the group velocity control and the pulse compression processes. The group velocity as well as the pulse reshaping are solely controlled by external voltages which makes it promising in quantum information and quantum communication processes. It is also proposed that the group velocity can be changed even more in an Er doped crystal while at the same time having a transmission band matching the telecommunication wavelength.

  8. High impact ionization rate in silicon by sub-picosecond THz electric field pulses (Conference Presentation)

    DEFF Research Database (Denmark)

    Tarekegne, Abebe Tilahun; Iwaszczuk, Krzysztof; Hirori, Hideki

    2017-01-01

    Summary form only given. Metallic antenna arrays fabricated on high resistivity silicon are used to localize and enhance the incident THz field resulting in high electric field pulses with peak electric field strength reaching several MV/cm on the silicon surface near the antenna tips. In such high...... electric field strengths high density of carriers are generated in silicon through impact ionization process. The high density of generated carriers induces a change of refractive index in silicon. By measuring the change of reflectivity of tightly focused 800 nm light, the local density of free carriers...... near the antenna tips is measured. Using the NIR probing technique, we observed that the density of carriers increases by over 8 orders of magnitude in a time duration of approximately 500 fs with an incident THz pulse of peak electric field strength 700 kV/cm. This shows that a single impact...

  9. Effects of High-voltage Pulse Electric Field Treatment on the Structure Stability of Konjac Glucomannan

    Institute of Scientific and Technical Information of China (English)

    YAO Min-Na; FAN Lin-Lin; LIU Ya-Nan; CHEN Qing-Ai; ZENG Yuan; JIAN Wen-Jie; PANG Jie

    2011-01-01

    Structures of KGM treated in two high-voltage pulse electric fields were characterized by infrared spectroscopy,Raman spectroscopy,X-ray diffraction and so on.The results showed that intermolecular hydrogen bonding interactions of KGM were reduced after being treated with high-voltage pulse electric field,but there was no significant effect on its fiber chain form and thermal characteristics.Results of the study can provide a useful reference for further study on the structure and property of KGM,and especially can provide theoretical basis for the effect of physical field on the foodstuff deep processing related to KGM.

  10. Permeabilization of plant tissues by monopolar pulsed electric fields: effect of frequency.

    Science.gov (United States)

    Asavasanti, Suvaluk; Ristenpart, William; Stroeve, Pieter; Barrett, Diane M

    2011-01-01

    Pulsed electric fields (PEF) nonthermally induce cell membrane permeabilization and thereby improve dehydration and extraction efficiencies in food plant materials. Effects of electrical field strength and number of pulses on plant tissue integrity have been studied extensively. Two previous studies on the effect of pulse frequency, however, did not provide a clear view: one study suggested no effect of frequency, while the other found a greater impact on tissue integrity at lower frequency. This study establishes the effect of pulse frequency on integrity of onion tissues. Changes in electrical characteristics, ion leakage, texture parameters, and percent weight loss were quantified for a wide range of pulse frequencies under conditions of fixed field strength and pulse number. Optical microscopy and viable-cell staining provided direct visualization of effects on individual cells. The key finding is that lower frequencies (f plant tissue. We hypothesize that cytoplasmic streaming plays a significant role in moving conductive ionic species from permeabilized cells to the intercellular space between plant cells, making subsequent pulses more efficacious at sufficiently low frequencies. The results suggest that decreasing the pulse frequency in PEF may minimize the number of pulses needed to achieve a desired amount of permeabilization, thus lowering the total energy consumption. Practical Application: PEF cause pores to be formed in plant cell membranes, thereby improve moisture removal and potential extraction of desirable components. This study used in situ microscopic evaluation of onion cells, as they were pulsed with electric fields at different frequencies, to determine whether frequency was an important parameter. We illustrate that membranes were more effectively broken at lower frequencies as compared to higher frequencies. Application of this information will allow for improved design of PEF systems for more energy efficient dehydration or extraction of

  11. Tumour Cell Membrane Poration and Ablation by Pulsed Low-Intensity Electric Field with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Lijun Wang

    2015-03-01

    Full Text Available Electroporation is a physical method to increase permeabilization of cell membrane by electrical pulses. Carbon nanotubes (CNTs can potentially act like “lighting rods” or exhibit direct physical force on cell membrane under alternating electromagnetic fields thus reducing the required field strength. A cell poration/ablation system was built for exploring these effects of CNTs in which two-electrode sets were constructed and two perpendicular electric fields could be generated sequentially. By applying this system to breast cancer cells in the presence of multi-walled CNTs (MWCNTs, the effective pulse amplitude was reduced to 50 V/cm (main field/15 V/cm (alignment field at the optimized pulse frequency (5 Hz of 500 pulses. Under these conditions instant cell membrane permeabilization was increased to 38.62%, 2.77-fold higher than that without CNTs. Moreover, we also observed irreversible electroporation occurred under these conditions, such that only 39.23% of the cells were viable 24 h post treatment, in contrast to 87.01% cell viability without presence of CNTs. These results indicate that CNT-enhanced electroporation has the potential for tumour cell ablation by significantly lower electric fields than that in conventional electroporation therapy thus avoiding potential risks associated with the use of high intensity electric pulses.

  12. A novel application of pulsed electric field (PEF) processing for improving glutathione (GSH) antioxidant activity.

    Science.gov (United States)

    Wang, Jia; Wang, Ke; Wang, Ying; Lin, Songyi; Zhao, Ping; Jones, Gregory

    2014-10-15

    Glutathione (GSH) was treated by pulsed electric field (PEF) processing to investigate its effect on antioxidant activity. The antioxidant activity of GSH was evaluated using 2,2-diphenyl-1-picrylhydrazy (DPPH) radical inhibition. A Box-Behnken design (BBD) with three independent variables, which were concentration, electric field intensity and pulse frequency was used to establish the regression equation of second-order response surface. Optimal conditions were as follows: GSH concentration 8.86mg/mL, electric field intensity 9.74kV/cm and pulse frequency 2549.08Hz. The DPPH radical inhibition increased from 81.83% to 97.40%. Near-infrared spectroscopy (NIR) and mid-infrared spectroscopy (MIR) were used to analyse the change of structure and functional groups of GSH.

  13. Electric field induced needle-pulsed arc discharge carbon nanotube production apparatus: circuitry and mechanical design.

    Science.gov (United States)

    Kia, Kaveh Kazemi; Bonabi, Fahimeh

    2012-12-01

    A simple and low cost apparatus is reported to produce multiwall carbon nanotubes and carbon nano-onions by a low power short pulsed arc discharge reactor. The electric circuitry and the mechanical design details and a micro-filtering assembly are described. The pulsed-plasma is generated and applied between two graphite electrodes. The pulse width is 0.3 μs. A strong dc electric field is established along side the electrodes. The repetitive discharges occur in less than 1 mm distance between a sharp tip graphite rod as anode, and a tubular graphite as cathode. A hydrocarbon vapor, as carbon source, is introduced through the graphite nozzle in the cathode assembly. The pressure of the chamber is controlled by a vacuum pump. A magnetic field, perpendicular to the plasma path, is provided. The results show that the synergetic use of a pulsed-current and a dc power supply enables us to synthesize carbon nanoparticles with short pulsed plasma. The simplicity and inexpensiveness of this plan is noticeable. Pulsed nature of plasma provides some extra degrees of freedom that make the production more controllable. Effects of some design parameters such as electric field, pulse frequency, and cathode shape are discussed. The products are examined using scanning probe microscopy techniques.

  14. Electric field induced needle-pulsed arc discharge carbon nanotube production apparatus: Circuitry and mechanical design

    Science.gov (United States)

    Kia, Kaveh Kazemi; Bonabi, Fahimeh

    2012-12-01

    A simple and low cost apparatus is reported to produce multiwall carbon nanotubes and carbon nano-onions by a low power short pulsed arc discharge reactor. The electric circuitry and the mechanical design details and a micro-filtering assembly are described. The pulsed-plasma is generated and applied between two graphite electrodes. The pulse width is 0.3 μs. A strong dc electric field is established along side the electrodes. The repetitive discharges occur in less than 1 mm distance between a sharp tip graphite rod as anode, and a tubular graphite as cathode. A hydrocarbon vapor, as carbon source, is introduced through the graphite nozzle in the cathode assembly. The pressure of the chamber is controlled by a vacuum pump. A magnetic field, perpendicular to the plasma path, is provided. The results show that the synergetic use of a pulsed-current and a dc power supply enables us to synthesize carbon nanoparticles with short pulsed plasma. The simplicity and inexpensiveness of this plan is noticeable. Pulsed nature of plasma provides some extra degrees of freedom that make the production more controllable. Effects of some design parameters such as electric field, pulse frequency, and cathode shape are discussed. The products are examined using scanning probe microscopy techniques.

  15. Self-resonant Coil for Contactless Electrical Conductivity Measurement under Pulsed Ultra-high Magnetic Fields

    CERN Document Server

    Nakamura, Daisuke; Takeyama, Shojiro

    2014-01-01

    In this study, we develop experimental apparatus for contactless electrical conductivity measurements under pulsed high magnetic fields over 100 T using a self-resonant-type high-frequency circuit. The resonant power spectra were numerically analyzed, and the conducted simulations showed that the apparatus is optimal for electrical conductivity measurements of materials with high electrical conductivity. The newly developed instruments were applied to a high-temperature cuprate superconductor La$_{2-x}$Sr$_x$CuO$_4$ to show conductivity changes in magnetic fields up to 102 T with a good signal-to-noise ratio. The upper critical field was determined with high accuracy.

  16. Eradication of multidrug-resistant pseudomonas biofilm with pulsed electric fields.

    Science.gov (United States)

    Khan, Saiqa I; Blumrosen, Gaddi; Vecchio, Daniela; Golberg, Alexander; McCormack, Michael C; Yarmush, Martin L; Hamblin, Michael R; Austen, William G

    2016-03-01

    Biofilm formation is a significant problem, accounting for over eighty percent of microbial infections in the body. Biofilm eradication is problematic due to increased resistance to antibiotics and antimicrobials as compared to planktonic cells. The purpose of this study was to investigate the effect of Pulsed Electric Fields (PEF) on biofilm-infected mesh. Prolene mesh was infected with bioluminescent Pseudomonas aeruginosa and treated with PEF using a concentric electrode system to derive, in a single experiment, the critical electric field strength needed to kill bacteria. The effect of the electric field strength and the number of pulses (with a fixed pulse length duration and frequency) on bacterial eradication was investigated. For all experiments, biofilm formation and disruption were confirmed with bioluminescent imaging and Scanning Electron Microscopy (SEM). Computation and statistical methods were used to analyze treatment efficiency and to compare it to existing theoretical models. In all experiments 1500 V are applied through a central electrode, with pulse duration of 50 μs, and pulse delivery frequency of 2 Hz. We found that the critical electric field strength (Ecr) needed to eradicate 100-80% of bacteria in the treated area was 121 ± 14 V/mm when 300 pulses were applied, and 235 ± 6.1 V/mm when 150 pulses were applied. The area at which 100-80% of bacteria were eradicated was 50.5 ± 9.9 mm(2) for 300 pulses, and 13.4 ± 0.65 mm(2) for 150 pulses. 80% threshold eradication was not achieved with 100 pulses. The results indicate that increased efficacy of treatment is due to increased number of pulses delivered. In addition, we that showed the bacterial death rate as a function of the electrical field follows the statistical Weibull model for 150 and 300 pulses. We hypothesize that in the clinical setting, combining systemic antibacterial therapy with PEF will yield a synergistic effect leading to improved

  17. A Pulsed Electric Field (PEF) bench static system to study bacteria inactivation

    Energy Technology Data Exchange (ETDEWEB)

    Cortese, Pietro; Dellacasa, Giuseppe; Gemme, Roberto [Department of Science and Advanced Technology, Eastern Piedmont University, Viale Teresa Michel 11, 15121-Alessandria (Italy); Bonetta, Sara; Bonetta, Silvia; Carraro, Elisabetta; Motta, Francesca [Department of Environmental and Life Science, Eastern Piedmont University, Viale Teresa Michel 11, 15121-Alessandria (Italy); Paganoni, Marco; Pizzichemi, Marco [Physics Department G. Occhialini, University of Milano-Bicocca, Piazza della Scienza 3, 20126-Milano (Italy)

    2011-06-15

    Pulsed Electric Fields (PEF) technology is a promising non-thermal processing method for inactivation of microorganisms. A small PEF bench system able to treat a 0.4 ml static liquid volume has been built and tested at the laboratories of the Universita del Piemonte Orientale in Alessandria, Italy. The technique used to produce the required fields consists of charging high voltage cables of various lengths and subsequently discharge them on a cylindrical cell. The pulse intensity can be adjusted to reach a maximum electric field in the cell of about 35 kV/cm and the pulse frequency can reach 10 Hz. We describe the PEF system in some detail and, as a benchmark of its performances, we report preliminary results obtained on Escherichia coli (ATCC 25922) at 10{sup 9} Cfu/ml concentration suspended in a McIlvaine buffer (pH 7.2).

  18. Pre-breakdown cavitation development in the dielectric fluid in the inhomogeneous, pulsed electric fields

    CERN Document Server

    Shneider, Mikhail N

    2014-01-01

    We consider the development of pre-breakdown cavitation nanopores appearing in the dielectric fluid under the influence of the electrostrictive stresses in the inhomogeneous pulsed electric field. It is shown that three characteristic regions can be distinguished near the needle electrode. In the first region, where the electric field gradient is greatest, the cavitation nanopores, occurring during the voltage nanosecond pulse, may grow to the size at which an electron accelerated by the field inside the pores can acquire enough energy for excitation and ionization of the liquid on the opposite pore wall, i.e., the breakdown conditions are satisfied. In the second region, the negative pressure caused by the electrostriction is large enough for the cavitation initiation (which can be registered by optical methods), but, during the voltage pulse, the pores do not reach the size at which the potential difference across their borders becomes sufficient for ionization or excitation of water molecules. And, in the ...

  19. Pulsed direct current electric fields enhance osteogenesis in adipose-derived stromal cells.

    Science.gov (United States)

    Hammerick, Kyle E; James, Aaron W; Huang, Zubin; Prinz, Fritz B; Longaker, Michael T

    2010-03-01

    Adipose-derived stromal cells (ASCs) constitute a promising source of cells for regenerative medicine applications. Previous studies of osteogenic potential in ASCs have focused on chemicals, growth factors, and mechanical stimuli. Citing the demonstrated role electric fields play in enhancing healing in bone fractures and defects, we investigated the ability of pulsed direct current electric fields to drive osteogenic differentiation in mouse ASCs. Employing 50 Hz direct current electric fields in concert with and without osteogenic factors, we demonstrated increased early osteoblast-specific markers. We were also able to establish that commonly reported artifacts of electric field stimulation are not the primary mediators of the observed effects. The electric fields caused marked changes in the cytoskeleton. We used atomic force microscopy-based force spectroscopy to record an increase in the cytoskeletal tension after treatment with electric fields. We abolished the increased cytoskeletal stresses with the rho-associated protein kinase inhibitor, Y27632, and did not see any decrease in osteogenic gene expression, suggesting that the pro-osteogenic effects of the electric fields are not transduced via cytoskeletal tension. Electric fields may show promise as candidate enhancers of osteogenesis of ASCs and may be incorporated into cell-based strategies for skeletal regeneration.

  20. Cost analysis of commercial pasteurization of orange juice by pulsed electric fields

    Science.gov (United States)

    The cost of pulsed electric field (PEF) pasteurization of orange juice was estimated. The cost analysis was based on processing conditions that met the US FDA (5 log reduction) requirement for fruit juice pasteurization and that achieved a 2 month microbial shelf-life. PEF-treated samples processed ...

  1. Effect of pulsed electric field treatment on hot-boned muscles of different potential tenderness.

    Science.gov (United States)

    Suwandy, Via; Carne, Alan; van de Ven, Remy; Bekhit, Alaa El-Din A; Hopkins, David L

    2015-07-01

    In this study, the effect of pulsed electric field (PEF) treatment and ageing on the quality of beef M. longissimus lumborum (LL) and M. semimembranosus (SM) muscles was evaluated, including the tenderness, water loss and post-mortem proteolysis. Muscles were obtained from 12 steers (6 steers for each muscle), removed from the carcasses 4 hour postmortem and were treated with pulsed electric field within 2h. Six different pulsed electric field intensities (voltages of 5 and 10 kV × frequencies of 20, 50 and 90 Hz) plus a control were applied to each muscle to determine the optimum treatment conditions. Beef LL was found to get tougher with increasing treatment frequency whereas beef SM muscle was found to have up to 21.6% reduction in the shear force with pulsed electric field treatment. Post-mortem proteolysis showed an increase in both troponin and desmin degradation in beef LL treated with low intensity PEF treatment (20 Hz) compared to non-treated control samples.

  2. Conductive plastic film electrodes for Pulsed Electric Field (PEF) treatment : A proof of principle

    NARCIS (Netherlands)

    Roodenburg, B.; Haan, S.W.H. de; Boxtel, L.B.J. van; Hatt, V.; Wouters, P.C.; Coronel, P.; Ferreira, J.A.

    2010-01-01

    Nowadays Pulsed Electric Field (PEF) treatment of food needs to be performed prior to packaging, either hygienic or aseptic packaging is necessary. New techniques for PEF treatment after packaging can be considered when plastic conductive (film) electrodes can be integrated within the package, so th

  3. Conductive plastic film electrodes for Pulsed Electric Field (PEF) treatment : A proof of principle

    NARCIS (Netherlands)

    Roodenburg, B.; Haan, S.W.H. de; Boxtel, L.B.J. van; Hatt, V.; Wouters, P.C.; Coronel, P.; Ferreira, J.A.

    2010-01-01

    Nowadays Pulsed Electric Field (PEF) treatment of food needs to be performed prior to packaging, either hygienic or aseptic packaging is necessary. New techniques for PEF treatment after packaging can be considered when plastic conductive (film) electrodes can be integrated within the package, so

  4. Pulsed Electric Field for protein release of the microalgae Chlorella vulgaris and Neochloris oleoabundans

    NARCIS (Netherlands)

    Lam, 't Gerard; Postma, P.R.; Fernandes, D.A.; Timmermans, R.A.H.; Vermuë, M.H.; Barbosa, M.J.; Eppink, M.H.; Wijffels, R.H.; Olivieri, G.

    2017-01-01

    Pulsed Electric Field (PEF) is currently discussed as promising technology for mild and scalable cell disintegration of microalgae. In this study Chlorella vulgaris and Neochloris oleoabundans have been subjected to batch and continuous PEF treatments under a wide range of operating conditions

  5. Electric field in an AC dielectric barrier discharge overlapped with a nanosecond pulse discharge

    Science.gov (United States)

    Goldberg, Benjamin M.; Shkurenkov, Ivan; Adamovich, Igor V.; Lempert, Walter R.

    2016-08-01

    The effect of ns discharge pulses on the AC barrier discharge in hydrogen in plane-to-plane geometry is studied using time-resolved measurements of the electric field in the plasma. The AC discharge was operated at a pressure of 300 Torr at frequencies of 500 and 1750 Hz, with ns pulses generated when the AC voltage was near zero. The electric field vector is measured by ps four-wave mixing technique, which generates coherent IR signal proportional to the square of electric field. Absolute calibration was done using an electrostatic (sub-breakdown) field applied to the discharge electrodes, when no plasma was generated. The results are compared with one-dimensional kinetic modeling of the AC discharge and the nanosecond pulse discharge, predicting behavior of both individual micro-discharges and their cumulative effect on the electric field distribution in the electrode gap, using stochastic averaging based on the experimental micro-discharge temporal probability distribution during the AC period. Time evolution of the electric field in the AC discharge without ns pulses, controlled by a superposition of random micro-discharges, exhibits a nearly ‘flat top’ distribution with the maximum near breakdown threshold, reproduced quite well by kinetic modeling. Adding ns pulse discharges on top of the AC voltage waveform changes the AC discharge behavior in a dramatic way, inducing transition from random micro-discharges to a more regular, near-1D discharge. In this case, reproducible volumetric AC breakdown is produced at a well-defined moment after each ns pulse discharge. During the reproducible AC breakdown, the electric field in the plasma exhibits a sudden drop, which coincides in time with a well-defined current pulse. This trend is also predicted by the kinetic model. Analysis of kinetic modeling predictions shows that this effect is caused by large-volume ionization and neutralization of surface charges on the dielectrics by ns discharge pulses. The present

  6. Evidence that pulsed electric field treatment enhances the cell wall porosity of yeast cells.

    Science.gov (United States)

    Ganeva, Valentina; Galutzov, Bojidar; Teissie, Justin

    2014-02-01

    The application of rectangular electric pulses, with 0.1-2 ms duration and field intensity of 2.5-4.5 kV/cm, to yeast suspension mediates liberation of cytoplasmic proteins without cell lysis. The aim of this study was to evaluate the effect of pulsed electric field with similar parameters on cell wall porosity of different yeast species. We found that electrically treated cells become more susceptible to lyticase digestion. In dependence on the strain and the electrical conditions, cell lysis was obtained at 2-8 times lower enzyme concentration in comparison with control untreated cells. The increase of the maximal lysis rate was between two and nine times. Furthermore, when applied at low concentration (1 U/ml), the lyticase enhanced the rate of protein liberation from electropermeabilized cells without provoking cell lysis. Significant differences in the cell surface of control and electrically treated cells were revealed by scanning electron microscopy. Data presented in this study allow us to conclude that electric field pulses provoke not only plasma membrane permeabilization, but also changes in the cell wall structure, leading to increased wall porosity.

  7. Nanoparticle mediated thermal ablation of breast cancer cells using a nanosecond pulsed electric field.

    Science.gov (United States)

    Burford, Christopher D; Bhattacharyya, Kiran D; Boriraksantikul, Nattaphong; Whiteside, Paul J D; Robertson, Benjamin P; Peth, Sarah M; Islam, Naz E; Viator, John A

    2013-06-01

    In the past, ablation of cancer cells using radiofrequency heating techniques has been demonstrated, but the current methodology has many flaws, including inconsistent tumor ablation and significant ablation of normal cells. Other researchers have begun to develop a treatment that is more selective for cancer cells using metallic nanoparticles and constant electric field exposure. In these studies, cell necrosis is induced by heating antibody functionalized metallic nanoparticles attached to cancer cells. Our approach to studying this phenomenon is to use similarly functionalized metallic nanoparticles that are specific for the T47D breast cancer cell line, exposing these nanoparticle cell conjugates to a nanosecond pulsed electric field. Using fluorescent, polystyrene-coated, iron-oxide nanoparticles, the results of our pilot study indicated that we were able to ablate up to approximately 80% of the cells using 60 ns pulses in increasing numbers of pulses and up to approximately 90% of the cells using 300 ns pulses in increasing numbers of pulses. These quantities of ablated cells were achieved using a cumulative exposure time 6 orders of magnitude less than most in vitro constant electric field studies.

  8. Inactivation of microorganisms within collagen gel biomatrices using pulsed electric field treatment.

    Science.gov (United States)

    Griffiths, Sarah; Maclean, Michelle; Anderson, John G; MacGregor, Scott J; Grant, M Helen

    2012-02-01

    Pulsed electric field (PEF) treatment was examined as a potential decontamination method for tissue engineering biomatrices by determining the susceptibility of a range of microorganisms whilst within a collagen gel. High intensity pulsed electric fields were applied to collagen gel biomatrices containing either Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Candida albicans, Saccharomyces cerevisiae or the spores of Aspergillus niger. The results established varying degrees of microbial PEF susceptibility. When high initial cell densities (10(6)-10(7) CFU ml(-1)) were PEF treated with 100 pulses at 45 kV cm(-1), the greatest log reduction was achieved with S. cerevisiae (~6.5 log(10) CFU ml(-1)) and the lowest reduction achieved with S. epidermidis (~0.5 log(10) CFU ml(-1)). The results demonstrate that inactivation is influenced by the intrinsic properties of the microorganism treated. Further investigations are required to optimise the microbial inactivation kinetics associated with PEF treatment of collagen gel biomatrices.

  9. Control of predators in industrial scale microalgae cultures with Pulsed Electric Fields.

    Science.gov (United States)

    Rego, D; Redondo, L M; Geraldes, V; Costa, L; Navalho, J; Pereira, M T

    2015-06-01

    This work describes the utilization of Pulsed Electric Fields to control the protozoan contamination of a microalgae culture, in an industrial 2.7 m(3) microalgae photobioreactor. The contaminated culture was treated with Pulsed Electric Fields, PEF, for 6h with an average of 900 V/cm, 65 μs pulses of 50 Hz. Working with recirculation, all the culture was uniformly exposed to the PEF throughout the assay. The development of the microalgae and protozoan populations was followed and the results showed that PEF is effective on the selective elimination of protozoa from microalgae cultures, inflicting on the protozoa growth halt, death or cell rupture, without affecting microalgae productivity. Specifically, the results show a reduction of the active protozoan population of 87% after 6h treatment and 100% after few days of normal cultivation regime. At the same time, microalgae growth rate remained unaffected.

  10. The kinetics of inactivation of spheroidal microbial cells by pulsed electric fields

    CERN Document Server

    Lebovka, Nikolai

    2007-01-01

    The nature of non-exponential kinetics in microbial cells inactivation by pulsed electric fields (PEF) is discussed. It was demonstrated that possible mechanism of non-exponential kinetics can be related to orientational disorder in suspension of microbial cells of anisotropic form. A numerical studies of spheroidal cell suspensions was carried out. The most pronounced deviations from the exponential kinetics were observed for disordered suspensions of prolate spheroids at small electric field strength $E$ or at large aspect ratio $a$. For partially oriented suspensions, efficiency of inactivation enhances with increasing of order parameter and field strength. A possibility of the PEF-induced orientational ordering in microbial suspensions is discussed.

  11. Metal release in a stainless steel Pulsed Electric Field (PEF) system Part I. Effect of different pulse shapes; theory and experimental method

    NARCIS (Netherlands)

    Roodenburg, B.; Morren, J.; Berg, H.E.; Haan, S.W.H.de

    2005-01-01

    Liquid pumpable food is mostly pasteurised by heat treatment. In the last decennia there is an increasing interest in so-called Pulsed Electric Field (PEF) treatment. During this treatment food is pumped between two metal electrodes and exposed to short high electric field pulses, typical 2-4 kV mm-

  12. Is pulsed electric field still effective for RNA separation in capillary electrophoresis?

    Science.gov (United States)

    Li, Zhenqing; Dou, Xiaoming; Ni, Yi; Chen, Qinmiao; Cheng, Shuyi; Yamaguchi, Yoshinori

    2012-03-16

    Pulsed field capillary electrophoresis (PFCE) is a predominant technique to cope with difficulties in resolving large DNA strands, yet it is still unclear whether pulsed electric field is effective for the separation of higher mass RNA. In this paper we focused on the role of pulsed electric field in large RNA fragments analysis by comparing RNA separation performance in PFCE with that in constant field CE. Separation performance in terms of migration mobility, plate numbers, resolution, and selectivity has been tested for the analysis of RNA from 0.1 to 10.0 kilo nucleotide (knt) under different electrophoretic conditions. Denaturation, important to obtain uniform and identifiable peaks, was accomplished by heating the sample in 4.0M urea prior to analysis and the presence of 4.0M urea in the electrophoresis buffer. Results demonstrate that unlike DNA in PFCE, the pulsed electric field mainly affects the separation performance of RNA between 0.4 and 2.0 knt. The migration mobility of long RNA fragments is not a strong function of modulation depth and pulsed frequency. Moreover, the logarithm of RNA mobility is almost inversely proportional to the logarithm of molecule size up to 6.0 knt with correlation coefficient higher than 0.99 in all the polymer concentrations measured here. Resonance frequency of RNA in PFCE was also observed. While these initial experiments show no distinct advantages of using PFCE for RNA separation, they do take further step toward characterizing the migration behavior of RNA under pulsed field conditions.

  13. Influence of laser pulse on the autocorrelation function of H in a strong electric field

    Institute of Scientific and Technical Information of China (English)

    Lifei Wang; Guangcan Yang

    2009-01-01

    The autocorrelation function of electronic wave packet of hydrogen atom in a strong electric field below the zero-field ionization threshold is investigated in the formalism of semiclassical theory. It is found that the autocorrelation depends on the applied laser pulse significantly. In the case of narrow laser pulse, the reviving peaks in the autocorrelation can be attributed to the closed orbits of electrons, which are related to the classical dynamics of the system. But this correspondence is wiped out with increasing the laser width because of the interference among the adjacent reviving peaks.

  14. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Catrin F., E-mail: williamscf@cardiff.ac.uk [School of Engineering, Cardiff University, Queen' s Buildings, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom); School of Biosciences, Cardiff University, Main Building, Cathays Park, Cardiff, CF10 3AT Wales (United Kingdom); Geroni, Gilles M.; Pirog, Antoine; Lees, Jonathan; Porch, Adrian [School of Engineering, Cardiff University, Queen' s Buildings, Newport Road, Cardiff, CF24 3AA Wales (United Kingdom); Lloyd, David [School of Biosciences, Cardiff University, Main Building, Cathays Park, Cardiff, CF10 3AT Wales (United Kingdom)

    2016-08-29

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the “internet of things” is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  15. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    Science.gov (United States)

    Williams, Catrin F.; Geroni, Gilles M.; Pirog, Antoine; Lloyd, David; Lees, Jonathan; Porch, Adrian

    2016-08-01

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the "internet of things" is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  16. S. cerevisiae fermentation activity after moderate pulsed electric field pre-treatments.

    Science.gov (United States)

    Mattar, Jessy R; Turk, Mohammad F; Nonus, Maurice; Lebovka, Nikolai I; El Zakhem, Henri; Vorobiev, Eugene

    2015-06-01

    The batch fermentation process, inoculated by Pulsed Electric Field (PEF) treated wine yeasts (Saccharomyces cerevisiae Actiflore F33), was studied. PEF treatment was applied to the aqueous yeast suspensions ([Y] = 0.012 g/L) at the electric field strengths of E = 100 and 6000 V/cm using the same treatment protocol (number of pulses n = 1000, pulse duration ti = 100 μs, and pulse repetition time Δt = 100 ms). Electrical conductivity was increasing during and after the PEF treatment, which reflected cell electroporation. Then, fermentation was run for 150 h in an incubator (30 °C) with synchronic agitation. Electro-stimulation was revealing itself by the improvement of fermentation characteristics, and thus increased yeast metabolism. At the end of the lag phase (t = 40 h), fructose consumption in samples with electrically activated inoculum exceeded that of the control samples by ≈ 2.33 times for E = 100 V/cm and by ≈ 3.98 for E = 6000 V/cm. At the end of the log phase (120 h of fermentation), ≈ 30% mass reduction was reached in samples with PEF-treated inocula (E = 6000 V/cm), whereas the same mass reduction of the control sample required approximately 20 extra hours of fermentation.

  17. Measurements of Electric Field in a Nanosecond Pulse Discharge by 4-WAVE Mixing

    Science.gov (United States)

    Baratte, Edmond; Adamovich, Igor V.; Simeni Simeni, Marien; Frederickson, Kraig

    2017-06-01

    Picosecond four-wave mixing is used to measure temporally and Picosecond four-wave mixing is used to measure temporally and spatially resolved electric field in a nanosecond pulse dielectric discharge sustained in room air and in an atmospheric pressure hydrogen diffusion flame. Measurements of the electric field, and more precisely the reduced electric field (E/N) in the plasma is critical for determination rate coefficients of electron impact processes in the plasma, as well as for quantifying energy partition in the electric discharge among different molecular energy modes. The four-wave mixing measurements are performed using a collinear phase matching geometry, with nitrogen used as the probe species, at temporal resolution of about 2 ns . Absolute calibration is performed by measurement of a known electrostatic electric field. In the present experiments, the discharge is sustained between two stainless steel plate electrodes, each placed in a quartz sleeve, which greatly improves plasma uniformity. Our previous measurements of electric field in a nanosecond pulse dielectric barrier discharge by picosecond 4-wave mixing have been done in air at room temperature, in a discharge sustained between a razor edge high-voltage electrode and a plane grounded electrode (a quartz plate or a layer of distilled water). Electric field measurements in a flame, which is a high-temperature environment, are more challenging because the four-wave mixing signal is proportional to the to square root of the difference betwen the populations of N2 ground vibrational level (v=0) and first excited vibrational level (v=1). At high temperatures, the total number density is reduced, thus reducing absolute vibrational level populations of N2. Also, the signal is reduced further due to a wider distribution of N2 molecules over multiple rotational levels at higher temperatures, while the present four-wave mixing diagnostics is using spectrally narrow output of a ps laser and a high

  18. Enhanced anthocyanin extraction from red cabbage using pulsed electric field processing.

    Science.gov (United States)

    Gachovska, Tanya; Cassada, David; Subbiah, Jeyamkondan; Hanna, Milford; Thippareddi, Harshavardhan; Snow, Daniel

    2010-08-01

    This study was conducted to evaluate the effect of pulsed electric field (PEF) treatment on anthocyanin extraction from red cabbage using water as a solvent. Mashed cabbage was placed in a batch treatment chamber and subjected to PEF (2.5 kV/cm electric field strength; 15 micros pulse width and 50 pulses, specific energy 15.63 J/g). Extracted anthocyanin concentrations (16 to 889 microg/mL) were determined using HPLC. Heat and light stabilities of the control and PEF-treated samples, having approximately the same initial concentrations, were studied. PEF treatments enhanced total anthocyanin extraction in water from red cabbage by 2.15 times with a higher proportion of nonacylated forms than the control (P light stabilities of the PEF-treated samples and control samples were not significantly different (P > 0.05). Practical Application: An innovative pretreatment technology, pulsed electric field processing, enhanced total anthocyanin extraction in water from red cabbage by 2.15 times. Manufacturers of natural colors can use this technology to extract anthocyanins from red cabbage efficiently.

  19. Finite pulse effects on $e^{+}e^{-}$ pair creation from strong electric fields

    CERN Document Server

    Taya, Hidetoshi; Itakura, Kazunori

    2014-01-01

    We investigate electron-positron pair creation from the vacuum in a pulsed electric background field. Employing the Sauter-type pulsed field $E(t) = E_0 {\\rm sech}^2(t/\\tau)$ with height $E_0$ and width $\\tau$, we demonstrate explicitly the interplay between the non-perturbative and perturbative aspects of the pair creation in the background field. In the constant field limit (the long pulse limit), Schwinger's non-perturbative formula is reproduced, while in the short pulse limit the leading-order perturbative treatment is justified. We show that two dimensionless parameters $eE_0 \\tau^2$ and $eE_0 \\tau /m_e$ characterize the importance of multiple interactions with the fields and the transition from the perturbative to the non-perturbative regime. We also reveal that pair creation is enhanced compared to Schwinger's formula when the field strength is relativity weak $|eE_0|/m_e^2 \\lesssim 1$ and the pulse duration is relatively short $m\\tau \\lesssim 1$ and that the enhancement is predominantly described by ...

  20. The influence of size and shape of microorganism on pulsed electric field inactivation.

    Science.gov (United States)

    El-Hag, Ayman H; Jayaram, Shesha H; Gonzalez, Oscar Rodriguez; Griffiths, M W

    2011-09-01

    In this paper the effect of microorganism size and shape on the killing efficiency of pulsed electric field (PEF) is investigated both experimentally and using a transient finite element program. The effect of cell size, membrane thickness, cell shape (spherical, elliptical, and cylindrical) on the calculated transmembrane voltage is studied. It has been found that both the cell size and cell membrane thickness have significant effect on the induced field across the cell membrane. The findings of the simulation results have been evaluated by comparing the trends with some experimental results. Five different types of microorganisms that have different shapes and dimensions have been inoculated with water at a conductivity level of 100 μS/cm and have been treated with the application of a pulsed electric field of 70 kV/cm. Significant difference in bacteria reduction was noticed between the treated cells which could be attributed to the cell size and shape.

  1. Modification of Pulsed Electric Field Conditions Results in Distinct Activation Profiles of Platelet-Rich Plasma

    Science.gov (United States)

    Frelinger, Andrew L.; Gerrits, Anja J.; Garner, Allen L.; Torres, Andrew S.; Caiafa, Antonio; Morton, Christine A.; Berny-Lang, Michelle A.; Carmichael, Sabrina L.; Neculaes, V. Bogdan; Michelson, Alan D.

    2016-01-01

    Background Activated autologous platelet-rich plasma (PRP) used in therapeutic wound healing applications is poorly characterized and standardized. Using pulsed electric fields (PEF) to activate platelets may reduce variability and eliminate complications associated with the use of bovine thrombin. We previously reported that exposing PRP to sub-microsecond duration, high electric field (SMHEF) pulses generates a greater number of platelet-derived microparticles, increased expression of prothrombotic platelet surfaces, and differential release of growth factors compared to thrombin. Moreover, the platelet releasate produced by SMHEF pulses induced greater cell proliferation than plasma. Aims To determine whether sub-microsecond duration, low electric field (SMLEF) bipolar pulses results in differential activation of PRP compared to SMHEF, with respect to profiles of activation markers, growth factor release, and cell proliferation capacity. Methods PRP activation by SMLEF bipolar pulses was compared to SMHEF pulses and bovine thrombin. PRP was prepared using the Harvest SmartPreP2 System from acid citrate dextrose anticoagulated healthy donor blood. PEF activation by either SMHEF or SMLEF pulses was performed using a standard electroporation cuvette preloaded with CaCl2 and a prototype instrument designed to take into account the electrical properties of PRP. Flow cytometry was used to assess platelet surface P-selectin expression, and annexin V binding. Platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), endothelial growth factor (EGF) and platelet factor 4 (PF4), and were measured by ELISA. The ability of supernatants to stimulate proliferation of human epithelial cells in culture was also evaluated. Controls included vehicle-treated, unactivated PRP and PRP with 10 mM CaCl2 activated with 1 U/mL bovine thrombin. Results PRP activated with SMLEF bipolar pulses or thrombin had similar light scatter profiles, consistent with the

  2. C-phycocyanin extraction assisted by pulsed electric field from Artrosphira platensis.

    Science.gov (United States)

    Martínez, Juan Manuel; Luengo, Elisa; Saldaña, Guillermo; Álvarez, Ignacio; Raso, Javier

    2017-09-01

    This paper assesses the application of pulsed electric fields (PEF) to the fresh biomass of Artrhospira platensis in order to enhance the extraction of C-phycocyanin into aqueous media. Electroporation of A. platensis depended on both electric field strength and treatment duration. The minimum electric field intensity for detecting C-phycocyanin in the extraction medium was 15kV/cm after the application of a treatment time 150μs (50 pulses of 3μs). However higher electric field strength were required when shorter treatment times were applied. Response surface methodology was used in order to investigate the influence of electric field strength (15-25kV/cm), treatment time (60-150μs), and temperature of application of PEF (10-40°C) on C-phycocyanin extraction yield (PEY). The increment of the temperature PEF treatment reduced the electric field strength and the treatment time required to obtain a given PEY and, consequently decreased the total specific energy delivered by the treatment. For example, the increment of temperature from 10°C to 40°C permitted to reduce the electric field strength required to extract 100mg/g dw of C-phycocyanin from 25 to 18kV/cm, and the specific energy input from 106.7 to 67.5kJ/Kg. Results obtained in this investigation demonstrated PEF's potential for selectively extraction C-phycocyanin from fresh A. platensis biomass. The purity of the C-phycocyanin extract obtained from the electroporated cells was higher than that obtained using other techniques based on the cell complete destruction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. The cluster size transformation model of molten alloy under pulse electric field

    Institute of Scientific and Technical Information of China (English)

    ZHANG ZhenBin; WANG JianZhong; QI JinGang; WANG Bing; HE LiJia; CANG DaQiang

    2008-01-01

    Based on the electric dipole theory,the coupled field distribution of pulse electric field (PEF) with electric dipole field around the cluster in superheated molten alloy is simulated under the effect of PEF. For the difference of electro-migration,the atom of solute and solution will accumulate around the cluster,and then the smaller cluster may reorganize and grow up under the action of the coupled field.We also apply the electrostatic induction theory to analyze the bearing behavior of the half side of the cluster. The bigger the cluster is,the stronger the electrostatic force is,therefore,the bigger cluster's stability is weak apparently. The study indicates that the cluster in the superheated molten has the homogeneous tendency under the effect of PEF.

  4. The cluster size transformation model of molten alloy under pulse electric field

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on the electric dipole theory, the coupled field distribution of pulse electric field (PEF) with electric dipole field around the cluster in superheated molten alloy is simulated under the effect of PEF. For the difference of electro-migration, the atom of solute and solution will accumulate around the cluster, and then the smaller cluster may reorganize and grow up under the action of the coupled field. We also apply the electrostatic induction theory to analyze the bearing behavior of the half side of the cluster. The bigger the cluster is, the stronger the electrostatic force is, therefore, the bigger cluster’s stability is weak apparently. The study indi- cates that the cluster in the superheated molten has the homogeneous tendency under the effect of PEF.

  5. An assessment of potential applications with pulsed electric field in wines

    Directory of Open Access Journals (Sweden)

    Drosou Foteini

    2017-01-01

    Full Text Available Pulsed electric fields (PEF is a non-thermal processing technology that uses instantaneous, pulses of high voltage for a short period in the range of milliseconds to microseconds; the application of high intensity electric field on toasted wood chips leads to a quick diffusion of extractable molecules. Currently most PEF studies, in the field of oenology, have been focusing on the application of PEF as a pretreatment of grape musts by examining the microbial inactivation and the enhancement of polyphenol extraction. In this study a post-treatment of wine is introduced as method to enhance the wood flavor in the wine with a green noninvasive technology. Major phenolic aldehydes that have been identified as the characteristic compounds of oak volatile compounds were selected as markers and were analyzed instrumentally to compare the influence of PEF processing to non-treated samples. PEF treated samples brought about higher concentrations of the examined oak compounds in the samples treated with PEF, which may explain the advantages of its application. The modulation of the intensity of the electric field and the period of pulses influenced the concentrations of the volatile phenols that were leached out. Differences found between the assayed treatments indicate that PEF application could be a potential practice for a rapid extraction of volatile compounds from oak.

  6. Exploring the Effects of Pulsed Electric Field Processing Parameters on Polyacetylene Extraction from Carrot Slices

    Directory of Open Access Journals (Sweden)

    Ingrid Aguiló-Aguayo

    2015-03-01

    Full Text Available The effects of various pulsed electric field (PEF parameters on the extraction of polyacetylenes from carrot slices were investigated. Optimised conditions with regard to electric field strength (1–4 kV/cm, number of pulses (100–1500, pulse frequency (10–200 Hz and pulse width (10–30 μs were identified using response surface methodology (RSM to maximise the extraction of falcarinol (FaOH, falcarindiol (FaDOH and falcarindiol-3-acetate (FaDOAc from carrot slices. Data obtained from RSM and experiments fitted significantly (p < 0.0001 the proposed second-order response functions with high regression coefficients (R2 ranging from 0.82 to 0.75. Maximal FaOH (188%, FaDOH (164.9% and FaDOAc (166.8% levels relative to untreated samples were obtained from carrot slices after applying PEF treatments at 4 kV/cm with 100 number of pulses of 10 μs at 10 Hz. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E% ranging from 0.68% to 3.58%.

  7. Exploring the effects of pulsed electric field processing parameters on polyacetylene extraction from carrot slices.

    Science.gov (United States)

    Aguiló-Aguayo, Ingrid; Abreu, Corina; Hossain, Mohammad B; Altisent, Rosa; Brunton, Nigel; Viñas, Inmaculada; Rai, Dilip K

    2015-03-02

    The effects of various pulsed electric field (PEF) parameters on the extraction of polyacetylenes from carrot slices were investigated. Optimised conditions with regard to electric field strength (1-4 kV/cm), number of pulses (100-1500), pulse frequency (10-200 Hz) and pulse width (10-30 μs) were identified using response surface methodology (RSM) to maximise the extraction of falcarinol (FaOH), falcarindiol (FaDOH) and falcarindiol-3-acetate (FaDOAc) from carrot slices. Data obtained from RSM and experiments fitted significantly (p < 0.0001) the proposed second-order response functions with high regression coefficients (R2) ranging from 0.82 to 0.75. Maximal FaOH (188%), FaDOH (164.9%) and FaDOAc (166.8%) levels relative to untreated samples were obtained from carrot slices after applying PEF treatments at 4 kV/cm with 100 number of pulses of 10 μs at 10 Hz. The predicted values from the developed quadratic polynomial equation were in close agreement with the actual experimental values with low average mean deviations (E%) ranging from 0.68% to 3.58%.

  8. Optimisation extraction of chondroitin sulfate from fish bone by high intensity pulsed electric fields.

    Science.gov (United States)

    He, Guidan; Yin, Yongguang; Yan, Xiaoxia; Yu, Qingyu

    2014-12-01

    High intensity pulsed electric fields (PEF) was used to extract chondroitin sulphate (CS) from fish bone. Results show that PEF extraction speed is much faster, and the content of CS is much higher compared with traditional methods. Variation of PEF parameters and the content of CS were determined by single factor experiments. The processing conditions were optimised by quadratic general rotary unitised design experiments. The maximum yield of 6.92 g/L was achieved under the following conditions: material-liquid ratio of 1:15 g/mL, electric field intensity of 16.88 kV/cm, pulse number of 9, and NaOH concentration of 3.24%. The purity of CS was analysed by agarose gel electrophoresis. CS purity was high, and the extract did not contain any other glycosaminoglycans. PEF can be widely used to extract CS with non-thermal performance, high speed, and low pollution.

  9. Dynamic effects and applications for nanosecond pulsed electric fields in cells and tissues

    Science.gov (United States)

    Beebe, Stephen J.; Blackmore, Peter F.; Hall, Emily; White, Jody A.; Willis, Lauren K.; Fauntleroy, Laura; Kolb, Juergen F.; Schoenbach, Karl H.

    2005-04-01

    Nanosecond, high intensity pulsed electric fields [nsPEFs] that are below the plasma membrane [PM] charging time constant have decreasing effects on the PM and increasing effects on intracellular structures and functions as the pulse duration decreases. When human cell suspensions were exposed to nsPEFs where the electric fields were sufficiently intense [10-300ns, platelets. These included Ca2+ mobilization from intracellular stores [endoplasmic reticulum] and subsequently through store-operated Ca2+ channels in the PM. In addition, platelet activation measured as aggregation responses were observed in human platelets. Finally, when nsPEF conditions followed classical electroporation-mediated transfection, the expression intensity and number of GFP-expressing cells were enhanced above cells exposed to electroporation conditions alone. These studies demonstrate that application of nsPEFs to cells or tissues can modulate cell-signaling mechanisms with possible applications as a new basic science tool, cancer treatment, wound healing, and gene therapy.

  10. analysis of large electromagnetic pulse simulators using the electric field integral equation method in time domain

    CERN Document Server

    Jamali, J; Moini, R; Sadeghi, H

    2002-01-01

    A time-domain approach is presented to calculate electromagnetic fields inside a large Electromagnetic Pulse (EMP) simulator. This type of EMP simulator is used for studying the effect of electromagnetic pulses on electrical apparatus in various structures such as vehicles, a reoplanes, etc. The simulator consists of three planar transmission lines. To solve the problem, we first model the metallic structure of the simulator as a grid of conducting wires. The numerical solution of the governing electric field integral equation is then obtained using the method of moments in time domain. To demonstrate the accuracy of the model, we consider a typical EMP simulator. The comparison of our results with those obtained experimentally in the literature validates the model introduced in this paper.

  11. [Effects of high pulsed electric field on the secondary and tertiary structure of lipoxygenase].

    Science.gov (United States)

    Zhong, Kui; Hu, Xiao-Song; Wu, Ji-Hong; Chen, Fang; Liao, Xiao-Jun

    2009-03-01

    The effect of pulsed electric field (PEF) on the secondary and tertiary structure of lipoxygenase (LOX) in a buffer solution was analyzed using far UV-circular dichroism (CD) and fluorescence spectrophotometry, respectively. The secondary and tertiary structure of LOX changed after PEF treatment. The CD spectra of LOX also changed, with the intensity of two negative peaks and the content of alpha-helix significantly decreased (p electric field strength. The fluorescence intensity of LOX increased, and the relative fluorescence intensity of the two characteristic peaks of LOX emission spectra at 337 nm and 583 nm also showed a good linear correlation with the electric field strength. These results showed that the activity inactivation of LOX may be due to the alteration in secondary structure, and both had a good relation.

  12. Hydrodynamical flows in dielectric liquid in strong inhomogeneous pulsed electric field

    Science.gov (United States)

    Tereshonok, Dmitry V.; Babaeva, Natalia Yu; Naidis, George V.; Smirnov, Boris M.

    2016-12-01

    We consider a hydrodynamical flow of dielectric liquid near a high voltage needle-shaped electrode in a strong inhomogeneous pulsed electric field. It was shown that under a small rise time, a negative pressure area (pressure is less than critical pressure) appears near the electrode leading to the formation of a cavity in which electric breakdown can develop. A comparison of the dependence of the velocity of fluid near an electrode for two cases (taking into account the dependence of dielectric permeability of the liquid on the electric field and without taking it into account) was made. A field-dependent dielectric coefficient leads to the appearance of two local maximums of the velocities and increases the minimum pressure, thus lowering the possibility of cavitation. While under the constant value of dielectric permeability only one local maximum appears.

  13. Effects of combined exposure of Micrococcus luteus to nisin and pulsed electric fields

    NARCIS (Netherlands)

    Dutreux, N.; Notermans, S.; Góngora-Nieto, M.M.; Barbosa-Cánovas, G.V.; Swanson, B.G.

    2000-01-01

    Death and injury following exposure of Micrococcus luteus to nisin and pulsed electric field (PEF) treatment were investigated in phosphate buffer (pH 6.8, σ = 4.8 ms/cm at 20°C). Four types of experiment were carried out, a single treatment with nisin (100 IU/ml at 20°C for 2 h), a single PEF treat

  14. Effect of pulsed electric field on the rheological and colour properties of soy milk.

    Science.gov (United States)

    Xiang, Bob Y; Simpson, Marian V; Ngadi, Michael O; Simpson, Benjamin K

    2011-12-01

    The effects of pulsed electric field (PEF) treatments on rheological and colour properties of soy milk were evaluated. Flow behaviour, viscosity and rheological parameters of PEF-treated soy milk were monitored using a controlled stress rheometer. For PEF treatments, electric field intensity of 18, 20 and 22 kV cm(-1) and number of pulses of 25, 50, 75 and 100 were used. For the measurements of rheological properties of soy milk shear rates between 0 and 200 s(-1) was used. The rheological behaviour of control and the PEF-treated soy milk were described using a power law model. The PEF treatments affected the rheological properties of soy milk. Apparent viscosity of soy milk increased from 6.62 to 7.46 (10(-3) Pa s) with increase in electric field intensity from 18 to 22 kV cm(-1) and increase in the number of pulses from 0 to 100. The consistency index (K) of soy milk also changed with PEF treatments. Lightness (L*), red/greenness (a*) and yellowness/blueness (b*) of soy milk were affected by PEF treatments.

  15. Removal of phenol by activated alumina bed in pulsed high-voltage electric field

    Institute of Scientific and Technical Information of China (English)

    ZHU Li-nan; MA Jun; YANG Shi-dong

    2007-01-01

    A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe2+. The removal rate of phenol could reach 72.1 % when air aeration flow rate was 1200 ml/min, and 88.2 % when 0.05 mmol/L Fe2+ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.

  16. Investigating membrane nanoporation induced by bipolar pulsed electric fields via second harmonic generation

    Science.gov (United States)

    Moen, E. K.; Ibey, B. L.; Beier, H. T.; Armani, A. M.

    2016-09-01

    Electric pulses have become an effective tool for transporting cargo (DNA, drugs, etc.) across cell membranes. This enhanced transport is believed to occur through temporary pores formed in the plasma membrane. Traditionally, millisecond duration, monopolar (MP) pulses are used for electroporation, but bipolar (BP) pulses have proven equally effective as MP pulses with the added advantage of less cytotoxicity. With the goal of further reducing cytotoxic effects and inducing non-thermal, intra-cellular effects, researchers began investigating reduced pulse durations, pushing into the nanosecond regime. Cells exposed to these MP, nanosecond pulsed electric fields (nsPEFs) have shown increased repairable membrane permeability and selective channel activation. However, attempts to improve this further by moving to the BP pulse regime has proven unsuccessful. In the present work, we use second harmonic generation imaging to explore the structural effects of bipolar nsPEFs on the plasma membrane. By varying the temporal spacing between the pulse phases over several orders of magnitude and comparing the response to a single MP case, we systematically examine the disparity in cellular response. Our circuit-based model predicts that, as the temporal spacing increases several orders of magnitude, nanoporation increases and eventually exceeds the MP case. On the whole, our experimental data agree with this assertion; however, a detailed analysis of the data sets demonstrates that biological processes may play a larger role in the observed response than previously thought, dominating the effect for temporal spacing up to 5 μs. These findings could ultimately lead to understanding the biophysical mechanism underlying all electroporation.

  17. The effect of high voltage, high frequency pulsed electric field on slain ovine cortical bone.

    Science.gov (United States)

    Asgarifar, Hajarossadat; Oloyede, Adekunle; Zare, Firuz

    2014-04-01

    High power, high frequency pulsed electric fields known as pulsed power (PP) has been applied recently in biology and medicine. However, little attention has been paid to investigate the application of pulse power in musculoskeletal system and its possible effect on functional behavior and biomechanical properties of bone tissue. This paper presents the first research investigating whether or not PP can be applied safely on bone tissue as a stimuli and what will be the possible effect of these signals on the characteristics of cortical bone by comparing the mechanical properties of this type of bone pre and post expose to PP and in comparison with the control samples. A positive buck-boost converter was applied to generate adjustable high voltage, high frequency pulses (up to 500 V and 10 kHz). The functional behavior of bone in response to pulse power excitation was elucidated by applying compressive loading until failure. The stiffness, failure stress (strength) and the total fracture energy (bone toughness) were determined as a measure of the main bone characteristics. Furthermore, an ultrasonic technique was applied to determine and comprise bone elasticity before and after pulse power stimulation. The elastic property of cortical bone samples appeared to remain unchanged following exposure to pulse power excitation for all three orthogonal directions obtained from ultrasonic technique and similarly from the compression test. Nevertheless, the compressive strength and toughness of bone samples were increased when they were exposed to 66 h of high power pulsed electromagnetic field compared to the control samples. As the toughness and the strength of the cortical bone tissue are directly associated with the quality and integrity of the collagen matrix whereas its stiffness is primarily related to bone mineral content these overall results may address that although, the pulse power stimulation can influence the arrangement or the quality of the collagen network

  18. Regeneration and control of human fibroblast cell density by intermittently delivered pulsed electric fields.

    Science.gov (United States)

    Golberg, Alexander; Bei, Marianna; Sheridan, Robert L; Yarmush, Martin L

    2013-06-01

    Proliferative scarring is a human disease with neither available effective treatment nor relevant animal model. One of the hypotheses for scar formation involves deregulation of fibroblast signaling and delayed apoptosis. Here, we introduce a new chemical-free method for fibroblast density control in culture by intermittently delivered pulsed electric fields (IDPEF), which cause irreversible damage to cell membranes. Using 5-100 pulses with electric field strength of 150 V/mm, pulse duration 70 µs, and frequency of 1 Hz, we investigated the effects of PEF application on growth, death, and regeneration of normal human dermal fibroblasts in culture. We found that the fraction of fibroblasts that survive depends on the number of pulses applied and follows a Weibull distribution. We have successfully developed an IDPEF protocol that controls fibroblasts density in culture. Specifically, through application of IDPEF every 72 h for 12 days, we maintain a normal human dermal fibroblast density in the 3.1 ± 0.2 × 10(5) -1.4 ± 0.2 × 10(5)  cell/mL range. Our results suggest that IDPEFs may prove useful as a non-chemical method for fibroblast density control in human wound healing.

  19. Structural properties and digestibility of pulsed electric field treated waxy rice starch.

    Science.gov (United States)

    Zeng, Feng; Gao, Qun-Yu; Han, Zhong; Zeng, Xin-An; Yu, Shu-Juan

    2016-03-01

    Waxy rice starch was subjected to pulsed electric field (PEF) treatment at intensity of 30, 40 and 50kVcm(-1). The impact of PEF treatment on the granular morphology, molecular weight, semi-crystalline structure, thermal properties, and digestibility were investigated. The micrographs suggested that electric energy could act on the granule structure of starch granule, especially at high intensity of 50kVcm(-1). Gelatinization onset temperature, peak temperature, conclusion temperature and enthalpy value of PEF treated starches were lower than that of native starch. The 9nm lamellar peak of PEF treated starches decreased as revealed by small angle X-ray scattering. The relative crystallinity of treated starches decreased as the increase of electric field intensity. Increased rapidly digestible starch level and decreased slowly digestible starch level was found on PEF treated starches. These results would imply that PEF treatment induced structural changes in waxy rice starch significantly affected its digestibility.

  20. Finite pulse effects on fermion pair creation from strong electric fields

    Science.gov (United States)

    Taya, Hidetoshi; Fujii, Hirotsugu; Itakura, Kazunori

    2014-09-01

    In the early stage of heavy ion collisions, there appear extraordinarily strong (color) EM fields. In the presence of such strong fields, we encounter essentially new phenomena that are not observed in the vacuum: Among those is fermion pair creation from the vacuum. In this talk, we consider fermion pair creation from the vacuum in a strong electric field with finite duration. Employing the Sauter-type pulsed electric field with height E0 and width τ, we demonstrate explicitly the interplay between the non-perturbative and perturbative aspects of the pair creation in a strong field with finite duration. We identify that two dimensionless parameters ν = | g E0 | τ2 and γ = | g E0 | τ / m characterize the importance of multiple interactions with the field and the transition from the perturbative to the non-perturbative regime. We also show that the pair creation is enhanced compared to Schwinger's formula when the field strength is relativity weak | g E0 | / m2 < 1 and the pulse duration is relatively short mτ < 1 , and reveal that the enhancement is predominantly described by the lowest order perturbation with a single photon. We also discuss some recent developments and applications.

  1. [Pulsed electric fields inhibit tumor growth but induce myocardial injury of melanoma-bearing mice].

    Science.gov (United States)

    Pan, Fengying; Wu, Sha; Wang, Xiaoxu; Zhang, Xiaogang

    2016-07-01

    Objective To investigate the tumor inhibiting effect of pulsed electric fields (PEFs) on melanoma-bearing mice, and understand its influence on myocardial cells and cardial electrical activity. Methods The melanoma models of the BALB/c mice were established by subcutaneously injecting B16 melanoma cells. These mice were randomly divided into four groups. The treated groups received pulsed electric stimulation at pulse width of 1, 3, 5 ms, with field strength of 100 V/cm and frequency of 10 Hz for 10 minutes daily in 15 consecutive days. ECG of mice was recorded. Tumor volume was measured with vernier caliper. Morphological changes of tumors were observed by HE staining. The expression of proliferating cell nuclear antigen (PCNA) mRNA was tested by real-time quantitative PCR, and the expression of PCNA protein was detected by immunofluorescence histochemistry. The ultrastructural changes of the cardiac tissues were observed by transmission electron microscopy (TEM). The serum levels of cardial troponin T (cTnT) and creatine kinase isoenzyme MB (CK-MB) were detected by ELISA. Results Compared with the control group, tumor volumes in all treated groups were reduced 7 days after PEFs treatment; more melanin granules in tumor cells were found in the treated groups; the expressions of PCNA mRNA and protein were down-regulated in all treated groups, and there were greater changes in the groups receiving the bigger pulse width. Myocardial injury was found in 3 ms group and 5 ms group, and the expressions of cTnT and CK-MB were significantly higher than those in the control group. Conclusion PEFs can inhibit tumor growth in melanoma-bearing mice. Increase of pulse width will aggravate myocardial injury.

  2. Effect of pulsed electric fields on microbial inactivation and physico-chemical properties of whole porcine blood.

    Science.gov (United States)

    Boulaaba, Annika; Egen, Nathalie; Klein, Günter

    2014-04-01

    The objective of this study was to determine the lethal effectiveness of pulsed electric fields on the inactivation of the porcine blood endogenous microflora. Furthermore, the impact of pulsed electric field application on physico-chemical and sensory properties in this medium should be proved. Blood samples from a commercial abattoir in Germany were processed by a continuous pilot plant-pulsed electric field system at electric field strength of 11 kV/cm for treatment times of 163 and 209 µs. The applied pulse frequencies of 134 and 175 Hz correspond to an energy input of 91 and 114 kJ/kg, respectively. In these conditions, the effectiveness of pulsed electric field processing on microbial inactivation was limited: 1.35 log10 CFU/mL reduction of total aerobic plate count (p growth of total aerobic plate count (p electric field-treated blood samples. Pulsed electric field processing leads to a complete hemolysis of the red blood cells, in addition significant decreased L* (lightness), a* (redness) and b* (yellowness) values (p < 0.0001) were observed. Furthermore, changes in the sensory attributes color (changed from red to dark brown) and odor (changed from fresh to musty and tangy) were noticed.

  3. Intense picosecond pulsed electric fields inhibit proliferation and induce apoptosis of HeLa cells.

    Science.gov (United States)

    Zhang, Min; Xiong, Zheng-Ai; Chen, Wen-Juan; Yao, Cheng-Guo; Zhao, Zhong-Yong; Hua, Yuan-Yuan

    2013-06-01

    A picosecond pulsed electric field (psPEF) is a localized physical therapy for tumors that has been developed in recent years, and that may in the future be utilized as a targeted non‑invasive treatment. However, there are limited studies regarding the biological effects of psPEF on cells. Electric field amplitude and pulse number are the main parameters of psPEF that influence its biological effects. In this study, we exposed HeLa cells to a psPEF with a variety of electric field amplitudes, from 100 to 600 kV/cm, and various pulse numbers, from 1,000 to 3,000. An MTT assay was used to detect the growth inhibition, while flow cytometry was used to determine the occurrence of apoptosis and the cell cycle of the HeLa cells following treatment. The morphological changes during cell apoptosis were observed using transmission electron microscopy (TEM). The results demonstrated that the cell growth inhibition rate gradually increased, in correlation with the increasing electric field amplitude and pulse number, and achieved a plateau of maximum cell inhibition 12 h following the pulses. In addition, typical characteristics of HeLa cell apoptosis in the experimental groups were observed by TEM. The results demonstrated that the rate of apoptosis in the experimental groups was significantly elevated in comparison with the untreated group. In the treatment groups, the rate of apoptosis was greater in the higher amplitude groups than in the lower amplitude groups. The same results were obtained when the variable was the pulse number. Flow cytometric analysis indicated that the cell cycle of the HeLa cells was arrested at the G2/M phase following psPEF treatment. Overall, our results indicated that psPEF inhibited cell proliferation and induced cell apoptosis, and that these effects occurred in a dose-dependent manner. In addition, the results demonstrated that the growth of the HeLa cells was arrested at the G2/M phase following treatment. This study may provide a

  4. Pre-breakdown processes in a dielectric fluid in inhomogeneous pulsed electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Shneider, Mikhail N., E-mail: m.n.shneider@gmail.com [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Pekker, Mikhail [MMSolution, 6808 Walker Street, Philadelphia, Pennsylvania 19135 (United States)

    2015-06-14

    We consider the development of pre-breakdown cavitation nanopores appearing in the dielectric fluid under the influence of the electrostrictive stresses in the inhomogeneous pulsed electric field. It is shown that three characteristic regions can be distinguished near the needle electrode. In the first region, where the electric field gradient is greatest, the cavitation nanopores, occurring during the voltage nanosecond pulse, may grow to the size at which an electron accelerated by the field inside the pores can acquire enough energy for excitation and ionization of the liquid on the opposite pore wall, i.e., the breakdown conditions are satisfied. In the second region, the negative pressure caused by the electrostriction is large enough for the cavitation initiation (which can be registered by optical methods), but, during the voltage pulse, the pores do not reach the size at which the potential difference across their borders becomes sufficient for ionization or excitation of water molecules. And, in the third, the development of cavitation is impossible, due to an insufficient level of the negative pressure: in this area, the spontaneously occurring micropores do not grow and collapse under the influence of surface tension forces. This paper discusses the expansion dynamics of the cavitation pores and their most probable shape.

  5. Pre-breakdown processes in a dielectric fluid in inhomogeneous pulsed electric fields

    Science.gov (United States)

    Shneider, Mikhail N.; Pekker, Mikhail

    2015-06-01

    We consider the development of pre-breakdown cavitation nanopores appearing in the dielectric fluid under the influence of the electrostrictive stresses in the inhomogeneous pulsed electric field. It is shown that three characteristic regions can be distinguished near the needle electrode. In the first region, where the electric field gradient is greatest, the cavitation nanopores, occurring during the voltage nanosecond pulse, may grow to the size at which an electron accelerated by the field inside the pores can acquire enough energy for excitation and ionization of the liquid on the opposite pore wall, i.e., the breakdown conditions are satisfied. In the second region, the negative pressure caused by the electrostriction is large enough for the cavitation initiation (which can be registered by optical methods), but, during the voltage pulse, the pores do not reach the size at which the potential difference across their borders becomes sufficient for ionization or excitation of water molecules. And, in the third, the development of cavitation is impossible, due to an insufficient level of the negative pressure: in this area, the spontaneously occurring micropores do not grow and collapse under the influence of surface tension forces. This paper discusses the expansion dynamics of the cavitation pores and their most probable shape.

  6. Investigation of a direct effect of nanosecond pulse electric fields on mitochondria

    Science.gov (United States)

    Estlack, Larry E.; Roth, Caleb C.; Cerna, Cesario Z.; Wilmink, Gerald J.; Ibey, Bennett L.

    2014-03-01

    The unique cellular response to nanosecond pulsed electric field (nsPEF) exposure, as compared to longer pulse exposure, has been theorized to be due to permeabilization of intracellular organelles including the mitochondria. In this investigation, we utilized a high-throughput oxygen and pH sensing system (Seahorse® XF24 extracellular flux analyzer) to assess the mitochondrial activity of Jurkat and U937 cells after nsPEF. The XF Analyzer uses a transient micro-chamber of only a few μL in specialized cell culture micro-plates to enable oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) to be monitored in real-time. We found that for nsPEF exposures of 10 pulses at 10-ns pulse width and at 50 kV/cm e-field, we were able to cause an increase in OCR in both U937 and Jurkat cells. We also found that high pulse numbers (>100) caused a significant decrease in OCR. Higher amplitude 150 kV/cm exposures had no effect on U937 cells and yet they had a deleterious effect on Jurkat cells, matching previously published 24 hour survival data. These results suggest that the exposures were modulating metabolic activity in cells possibly due to direct effects on the mitochondria themselves. To validate this hypothesis, we isolated mitochondria from U937 cells and exposed them similarly and found no significant change in metabolic activity for any pulse number. In a final experiment, we removed calcium from the buffer solution that the cells were exposed in and found that no significant enhancement in metabolic activity was observed. These results suggest that direct permeabilization of the mitochondria is unlikely a primary effect of nsPEF exposure and calcium-mediated intracellular pathway activation is likely responsible for observed pulse-induced mitochondrial effects.

  7. Cutaneous papilloma and squamous cell carcinoma therapy utilizing nanosecond pulsed electric fields (nsPEF.

    Directory of Open Access Journals (Sweden)

    Dong Yin

    Full Text Available Nanosecond pulsed electric fields (nsPEF induce apoptotic pathways in human cancer cells. The potential therapeutic effective of nsPEF has been reported in cell lines and in xenograft animal tumor model. The present study investigated the ability of nsPEF to cause cancer cell death in vivo using carcinogen-induced animal tumor model, and the pulse duration of nsPEF was only 7 and 14 nano second (ns. An nsPEF generator as a prototype medical device was used in our studies, which is capable of delivering 7-30 nanosecond pulses at various programmable amplitudes and frequencies. Seven cutaneous squamous cell carcinoma cell lines and five other types of cancer cell lines were used to detect the effect of nsPEF in vitro. Rate of cell death in these 12 different cancer cell lines was dependent on nsPEF voltage and pulse number. To examine the effect of nsPEF in vivo, carcinogen-induced cutaneous papillomas and squamous cell carcinomas in mice were exposed to nsPEF with three pulse numbers (50, 200, and 400 pulses, two nominal electric fields (40 KV/cm and 31 KV/cm, and two pulse durations (7 ns and 14 ns. Carcinogen-induced cutaneous papillomas and squamous carcinomas were eliminated efficiently using one treatment of nsPEF with 14 ns duration pulses (33/39 = 85%, and all remaining lesions were eliminated after a 2nd treatment (6/39 = 15%. 13.5% of carcinogen-induced tumors (5 of 37 were eliminated using 7 ns duration pulses after one treatment of nsPEF. Associated with tumor lysis, expression of the anti-apoptotic proteins Bcl-xl and Bcl-2 were markedly reduced and apoptosis increased (TUNEL assay after nsPEF treatment. nsPEF efficiently causes cell death in vitro and removes papillomas and squamous cell carcinoma in vivo from skin of mice. nsPEF has the therapeutic potential to remove human squamous carcinoma.

  8. Nonlinear imaging of lipid membrane alterations elicited by nanosecond pulsed electric fields

    Science.gov (United States)

    Moen, Erick K.; Beier, Hope T.; Thompson, Gary L.; Armani, Andrea M.; Ibey, Bennett L.

    2015-03-01

    Second Harmonic Generation (SHG) imaging is a useful tool for examining the structure of interfaces between bulk materials. Recently, this technique was applied to detecting subtle perturbations in the structure of cellular membranes following nanosecond pulsed electric field (nsPEF) exposure. Monitoring the cell's outer membrane as it is exposed to nsPEF via SHG has demonstrated that nanoporation is likely the root cause for size-specific, increased cytoplasmic membrane permeabilization. It is theorized that the area of the membrane covered by these pores is tied to pulse intensity or duration. The extent of this effect along the cell's surface, however, has never been measured due to its temporal brevity and minute pore size. By enhancing the SHG technique developed and elucidated previously, we are able to obtain this information. Further, we vary the pulse width and amplitude of the applied stimulus to explore the mechanical changes of the membrane at various sites around the cell. By using this unique SHG imaging technique to directly visualize the change in order of phospholipids within the membrane, we are able to better understand the complex response of living cells to electric pulses.

  9. [Spectral analysis of polyphenol oxidase (PPO) and lipoxygenase (LOX) treated by pulsed electric field].

    Science.gov (United States)

    Luo, Wei; Zhang, Ruo-Bing; Chen, Jie; Wang, Li-Ming; Guan, Zhi-Cheng; Jia, Zhi-Dong

    2009-08-01

    Inactivation effect of pulsed electric field (PEF) on polyphenol oxidase (PPO) and lipoxygenase (LOX) was investigated using a laboratory PEF system with a coaxial treatment chamber. Circular dichroism (CD) and fluorescence analysis were used to study the conformation change of the protein. The experimental results show that PPO and LOX can be effectively inactivated by the PEF treatment. Inactivation effect of PPO and LOX increases with the increase in the applied electric strength and the treatment time. Activity of PPO and LOX can be reduced by 60.3% and 21.7% at 20 kV x cm(-1) after being treated for 320 micros respectively. The decrease of the negative peaks (208 and 215 nm in PPO spectra, 208 nm and 218 nm in LOX spectra) in CD spectra of PPO and LOX shows that PEF treatment caused a loss of alpha-helix and increase in beta-sheet content, indicating that conformation changes occur in the secondary structure of PPO and LOX enzyme. This effect was strengthened as the applied electric field increased: alpha-helical content of PPO and LOX was 56% and 29% after being treated at 8 kV x cm(-1), however, when the electric field was increased up to 20 kV x cm(-1), alpha-helical content of PPO and LOX decreased to 21% and 16% respectively. The decrease rate of alpha-helix and increase rate of beta-sheet in PPO are higher than LOX, indicating that the second conformation of PPO is less resistant to PEF treatment than LOX. The fluorescence intensity of LOX increases after PEF treatment. At the same time, increasing the applied pulsed electric field increases the fluorescence intensity emitted. Fluorescence measurements confirm that tertiary conformation changes occur in the local structure of LOX. However the possible mechanism of the conformation change induced by the PEF treatment is beyond the scope of the present investigation.

  10. Dynamic changes of [Ca2+]i in cerebellar granule cells exposed to pulsed electric fields

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Intracellular free Ca2+ concentration ([Ca2+]i) in embryonic chick cerebellar granule cells loaded with fluo-3/AM and exposed to a single pulsed electric field was investigated using a confocal laser scanning microscope and fluorescent microscope equipped with CCD video imaging system.The results showed that [Ca2+]i increased immediately and rose to the peak rapidly as the cells exposed to a single pulsed electric field.The amplitude and rate of the increases of [Ca2+]i depend on the intensity of external electric field.In the presence of Ca2+ chelant EGTA or Ca2+ channels blocker La3+ in the pulsation solutions,the increase of [Ca2+]i was still observable.It was also observed that [Ca2+]i of different intracellular areas in the cell elevated simultaneously while the peak of the increase of [Ca2+]i in the poles of the cell preceded to the peak in its somata and recovered to a plateau within a short time.

  11. Dynamic changes of [Ca2+]i in cerebellar granule cells exposed to pulsed electric fields

    Institute of Scientific and Technical Information of China (English)

    陈雅; 王彦; 孙彤; 张锦珠; 景向红; 李瑞午

    2000-01-01

    Intracellular free Ca2+ concentration ([Ca2+]i) in embryonic chick cerebellar granule cells loaded with fluo-3/AM and exposed to a single pulsed electric field was investigated using a confocal laser scanning microscope and fluorescent microscope equipped with CCD video imaging system. The results showed that [Ca2+]i increased immediately and rose to the peak rapidly as the cells exposed to a single pulsed electric field. The amplitude and rate of the increases of [Ca2+]i depend on the intensity of external electric field. In the presence of Ca2+ chelant EGTA or Ca2+ channels blocker La3+ in the pulsation solutions, the increase of [Ca2+]i was still observable. It was also observed that [Ca2+]i of different intracellular areas in the cell elevated simultaneously while the peak of the increase of [Ca2+]i in the poles of the cell preceded to the peak in its somata and recovered to a plateau within a short time.

  12. Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics

    Directory of Open Access Journals (Sweden)

    Irena Jeličić

    2012-03-01

    Full Text Available High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. However, a large number of scientific researches have been dedicated to investigation of impact of these methods on changes in constituents like milk fat, milk proteins and lactose as well as changes in mechanisms like renneting properties and coagulation of milk. The aim of this research was to give an overview of changes in milk constituents induced by high hydrostatic pressure, ultrasonification and pulsed electric field treatments as well as to suggest how these changes could improve conventional processes in the dairy industry.

  13. Growth of pulsed electric field exposed Escherichia coli in relation to inactivation and environmental factors.

    Science.gov (United States)

    Aronsson, Kristina; Borch, Elisabeth; Stenlöf, Bo; Rönner, Ulf

    2004-05-15

    Pulsed electric fields (PEF) have been proven to inactivate microorganisms during nonthermal conditions and have the potential to replace thermal processing as a method for food preservation. However, there is a need to understand the recovery and growth of survivors and potentially injured microorganisms following PEF processing. The purpose of this investigation was to study the growth of Escherichia coli at 10 degrees C following exposure to electrical field strengths (15, 22.5 and 30 kV/cm) in relation to inactivation and the amount of potentially sublethally injured cells. One medium was used as both a treatment medium and an incubation medium, to study the influence of environmental factors on the inactivation and the growth of the surviving population. The pH (5.0, 6.0 and 7.0) and water activity (1.00, 0.985 and 0.97) of the medium was varied by adding HCl and glycerol, respectively. Growth was followed continuously by measuring the optical density. The time-to-detection (td) and the maximum specific growth rate (micromax) were calculated from these data. Results showed that the PEF process did not cause any obvious sublethal injury to the E. coli cells. The number of survivors was a consequence of the combination of electrical field strength and environmental factors, with pH being the most prominent. Interestingly, the micromax of subsequent growth was influenced by the applied electrical field strength during the process, with an increased micromax at more intense electrical field strengths. In addition, the micromax was also influenced by the pH and water activity. The td, which could theoretically be considered as an increase in shelf life, was found to depend on a complex correlation between electrical field strength, pH and water activity. That could be explained by the fact that the td is a combination of the number of survivors, the recovery of sublethal injured cells and the growth rate of the survivors.

  14. Damage of cellular material under simultaneous application of pressure and pulsed electric field

    CERN Document Server

    Bazhal, M I; Vorobev, E I

    2000-01-01

    Influence of pulsed electric field (PEF) simultaneous to pressure treatment on moisture expression from fine-cut cellular raw material has been investigated. Dependencies of specific conductivity $\\sigma$, liquid yield $Y$, instantaneous flow rate $v$ and qualitative juice characteristics at different modes of PEF treatment are discussed. Three main consolidation phases were observed in a case of mechanical expression. A unified approach is proposed for liquid yield data analysis allowing to reduce the data scattering caused by differences in the quality of samples. Simultaneous application of pressure and PEF treatment allows to reveal a passive form of electrical damage. Pressure provokes the damage of defected cells, enhances diffusion migration of moisture in porous cellular material and depresses the cell resealing processes. PEF application at a moment when a sample specific electrical conductivity reaches minimum and pressure achieves its constant value seemed to be the most optimal.

  15. Generation of an isolated sub-30 attosecond pulse in a two-color laser field and a static electric field

    Institute of Scientific and Technical Information of China (English)

    Zhang Gang-Tai; Bai Ting-Ting; Zhang Mei-Guang

    2012-01-01

    We theoretically investigate high-order harmonic generation(HHG)from a helium ion model in a two-color laser field,which is synthesized by a fundamental pulse and its second harmonic pulse.It is shown that a supercontinuum spectrum can be generated in the two-color field.However,the spectral intensity is very low,limiting the application of the generated attosecond(as)pulse.By adding a static electric field to the synthesized two-color field,not only is the ionization yield of electrons contributing to the harmonic emission remarkably increased,but also the quantum paths of the HHG can be significantly modulated.As a result,the extension and enhancement of the supercontinuum spectrum are achieved,producing an intense isolated 26-as pulse with a bandwidth of about 170.5 eV.In particular,we also analyse the influence of the laser parameters on the ultrabroad supercontinuum spectrum and isolated sub-30-as pulse generation.

  16. Raising the avermectins production in Streptomyces avermitilis by utilizing nanosecond pulsed electric fields (nsPEFs)

    Science.gov (United States)

    Guo, Jinsong; Ma, Ruonan; Su, Bo; Li, Yinglong; Zhang, Jue; Fang, Jing

    2016-01-01

    Avermectins, a group of anthelmintic and insecticidal agents produced from Streptomyces avermitilis, are widely used in agricultural, veterinary, and medical fields. This study presents the first report on the potential of using nanosecond pulsed electric fields (nsPEFs) to improve avermectin production in S. avermitilis. The results of colony forming units showed that 20 pulses of nsPEFs at 10 kV/cm and 20 kV/cm had a significant effect on proliferation, while 100 pulses of nsPEFs at 30 kV/cm exhibited an obvious effect on inhibition of agents. Ultraviolet spectrophotometry assay revealed that 20 pulses of nsPEFs at 15 kV/cm increased avermectin production by 42% and reduced the time for reaching a plateau in fermentation process from 7 days to 5 days. In addition, the decreased oxidation reduction potential (ORP) and increased temperature of nsPEFs-treated liquid were evidenced to be closely associated with the improved cell growth and fermentation efficiency of avermectins in S. avermitilis. More importantly, the real-time RT-PCR analysis showed that nsPEFs could remarkably enhance the expression of aveR and malE in S. avermitilis during fermentation, which are positive regulator for avermectin biosynthesis. Therefore, the nsPEFs technology presents an alternative strategy to be developed to increase avermectin output in fermentation industry. PMID:27181521

  17. Raising the avermectins production in Streptomyces avermitilis by utilizing nanosecond pulsed electric fields (nsPEFs)

    Science.gov (United States)

    Guo, Jinsong; Ma, Ruonan; Su, Bo; Li, Yinglong; Zhang, Jue; Fang, Jing

    2016-05-01

    Avermectins, a group of anthelmintic and insecticidal agents produced from Streptomyces avermitilis, are widely used in agricultural, veterinary, and medical fields. This study presents the first report on the potential of using nanosecond pulsed electric fields (nsPEFs) to improve avermectin production in S. avermitilis. The results of colony forming units showed that 20 pulses of nsPEFs at 10 kV/cm and 20 kV/cm had a significant effect on proliferation, while 100 pulses of nsPEFs at 30 kV/cm exhibited an obvious effect on inhibition of agents. Ultraviolet spectrophotometry assay revealed that 20 pulses of nsPEFs at 15 kV/cm increased avermectin production by 42% and reduced the time for reaching a plateau in fermentation process from 7 days to 5 days. In addition, the decreased oxidation reduction potential (ORP) and increased temperature of nsPEFs-treated liquid were evidenced to be closely associated with the improved cell growth and fermentation efficiency of avermectins in S. avermitilis. More importantly, the real-time RT-PCR analysis showed that nsPEFs could remarkably enhance the expression of aveR and malE in S. avermitilis during fermentation, which are positive regulator for avermectin biosynthesis. Therefore, the nsPEFs technology presents an alternative strategy to be developed to increase avermectin output in fermentation industry.

  18. Pulsed electric field (PEF) as an intensification pretreatment for greener solvent lipid extraction from microalgae.

    Science.gov (United States)

    Zbinden, Mauricio D Antezana; Sturm, Belinda S M; Nord, Ryan D; Carey, William J; Moore, David; Shinogle, Heather; Stagg-Williams, Susan M

    2013-06-01

    Microalgae, with their high lipid content, are a promising feedstock for renewable fuels. Traditionally, human and environmentally toxic solvents have been used to extract these lipids, diminishing the sustainability of this process. Herein, pulsed electric field technology was utilized as a process intensification strategy to enhance lipid extraction from Ankistrodesmus falcatus wet biomass using the green solvent, ethyl acetate. The extraction efficiency for ethyl acetate without PEF was lower (83-88%) than chloroform. In addition, the ethyl acetate exhibited a 2-h induction period, while the chloroform showed no time dependence. Utilizing PEF technology resulted in 90% of the cells being lysed and a significant enhancement in the rate of lipid recovery using ethyl acetate. The increase in lipid recovery was due to the presence of the electric field and not due to temperature effects. The PEF technology uses less energy than other PEF systems reported in the literature.

  19. Kinetic model for the inactivation of Lactobacillus plantarum by pulsed electric fields.

    Science.gov (United States)

    Rodrigo, D; Ruíz, P; Barbosa-Cánovas, G V; Martínez, A; Rodrigo, M

    2003-03-25

    The kinetics of Lactobacillus plantarum inactivation by pulsed electric fields (PEF) was studied in two different growth stages (exponential and stationary), but in the same reference medium (0.6% peptone water). Electric field intensity and treatment time varied from 20 to 28 kV/cm and 30 to 240 micros, respectively. The experimental data showed that cells in the exponential growth stage were more sensitive to PEF treatment than those in the stationary stage. The inactivation data were adjusted to the Bigelow and Hülsheger models and the Weibull frequency distribution function, and constants were calculated for both growth stages in each model. The models were tested and their accuracy was assessed by using the Accuracy Factor. According to this parameter, the Weibull frequency distribution function gave better fittings for the inactivation by PEF than Bigelow or Hülsheger models. On the other hand, the Bigelow model gave a good accuracy factor and is simpler.

  20. Lipid vesicles in pulsed electric fields: Fundamental principles of the membrane response and its biomedical applications.

    Science.gov (United States)

    Perrier, Dayinta L; Rems, Lea; Boukany, Pouyan E

    2017-04-28

    The present review focuses on the effects of pulsed electric fields on lipid vesicles ranging from giant unilamellar vesicles (GUVs) to small unilamellar vesicles (SUVs), from both fundamental and applicative perspectives. Lipid vesicles are the most popular model membrane systems for studying biophysical and biological processes in living cells. Furthermore, as vesicles are made from biocompatible and biodegradable materials, they provide a strategy to create safe and functionalized drug delivery systems in health-care applications. Exposure of lipid vesicles to pulsed electric fields is a common physical method to transiently increase the permeability of the lipid membrane. This method, termed electroporation, has shown many advantages for delivering exogenous molecules including drugs and genetic material into vesicles and living cells. In addition, electroporation can be applied to induce fusion between vesicles and/or cells. First, we discuss in detail how research on cell-size GUVs as model cell systems has provided novel insight into the basic mechanisms of cell electroporation and associated phenomena. Afterwards, we continue with a thorough overview how electroporation and electrofusion have been used as versatile methods to manipulate vesicles of all sizes in different biomedical applications. We conclude by summarizing the open questions in the field of electroporation and possible future directions for vesicles in the biomedical field. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Monopole patch antenna for in vivo exposure to nanosecond pulsed electric fields.

    Science.gov (United States)

    Merla, C; Apollonio, F; Paffi, A; Marino, C; Vernier, P T; Liberti, M

    2016-07-15

    To explore the promising therapeutic applications of short nanosecond electric pulses, in vitro and in vivo experiments are highly required. In this paper, an exposure system based on monopole patch antenna is reported to perform in vivo experiments on newborn mice with both monopolar and bipolar nanosecond signals. Analytical design and numerical simulations of the antenna in air were carried out as well as experimental characterizations in term of scattering parameter (S 11) and spatial electric field distribution. Numerical dosimetry of the setup with four newborn mice properly placed in proximity of the antenna patch was carried out, exploiting a matching technique to decrease the reflections due to dielectric discontinuities (i.e., from air to mouse tissues). Such technique consists in the use of a matching dielectric box with dielectric permittivity similar to those of the mice. The average computed electric field inside single mice was homogeneous (better than 68 %) with an efficiency higher than 20 V m(-1) V(-1) for the four exposed mice. These results demonstrate the possibility of a multiple (four) exposure of small animals to short nanosecond pulses (both monopolar and bipolar) in a controlled and efficient way.

  2. Effect of pulsed electric field treatments on permeabilization and extraction of pigments from Chlorella vulgaris.

    Science.gov (United States)

    Luengo, Elisa; Condón-Abanto, Santiago; Álvarez, Ignacio; Raso, Javier

    2014-12-01

    The effect of pulsed electric field (PEF) treatments of different intensities on the electroporation of the cytoplasmatic membrane of Chlorella vulgaris, and on the extraction of carotenoids and chlorophylls were investigated. Staining the cells with propidium iodide before and after the PEF treatment revealed the existence of reversible and irreversible electroporation. Application of PEF treatments in the range of 20-25 kV cm(-1) caused most of the population of C. vulgaris to be irreversibly electroporated even at short treatment times (5 pulses of 3 µs). However, at lower electric field strengths (10 kV cm(-1)), cells that were reversibly electroporated were observed even after 50 pulses of 3 µs. The electroporation of C. vulgaris cells by PEF higher than 15 kV cm(-1) and duration is higher than 15 µs increased significantly the extraction yield of intracellular components of C. vulgaris. The application of a 20 kV cm(-1) for 75 μs increased the extraction yield just after the PEF treatment of the carotenoids, and chlorophylls a and b 0.5, 0.7, and 0.8 times, respectively. However, further increments in electric field strength and treatment time did not cause significant increments in the extraction yield. The extraction of carotenoids from PEF-treated C. vulgaris cells after 1 h of the application of the treatment significantly increased the extraction yield in comparison to the yield obtained from the cells extracted just after the PEF treatment. After PEF treatment at 20 kV cm(-1) for 75 µs, extraction yield for carotenoids, and chlorophylls a and b increased 1.2, 1.6, and 2.1 times, respectively. A high correlation was observed between irreversible electroporation and percentage of yield increase when the extraction was conducted after 1 h of the application of PEF treatment (R: 0.93), but not when the extraction was conducted just after PEF treatment (R: 0.67).

  3. Polarization of antiferroelectric ceramics for pulse capacitors under transient electric field

    Science.gov (United States)

    Xu, Ran; Xu, Zhuo; Feng, Yujun; Wei, Xiaoyong; Tian, Jingjing; Huang, Dong

    2016-06-01

    The polarization of (Pb0.94La0.04)[(Zr0.7Sn0.3)0.87Ti0.13]O3 antiferroelectric (AFE) ceramics under unipolar pulse electric field was studied, and the transient hysteresis loop was achieved. Compared to the traditional quasi-static results, the forward transition field increases and the backward transition field decreases. The forward and backward phase transitions can be deduced in microseconds scale. Under the transient field, the releasable energy density decreases significantly, while the stored energy density changes slightly. Consequently, the efficiency decreases and the declination of energy density under transient situation is verified by the charge-discharge experiment. The above results prove the necessity of the study of the transient behaviors in AFE and the limitation of quasi-static analysis.

  4. Design and Experiments of the High Voltage Pulsed Electric Fields Sterilization System

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xihai; FANG Junlong; SHEN Weizheng

    2008-01-01

    This experiment designed the pulsed electric fields (PEF) of high intensity of 100 kV. cml sterilization system. Fluorescent pseudomonas as target cell was operated 180 s in the PEF. By observing the difference of the bacteria before and after the disposal by TEM, it is found that the cell wails of the treated bacteria were broken. Irreversible perforations were formed on the cell membrane. The cell inclusions and cell fragments were leaked. The cell died as a result. The results showed that the PEF sterilization system designed can be used for liquid food sterilization experiments.

  5. Effect of pulsed electric field on the germination of barley seeds

    DEFF Research Database (Denmark)

    Dymek, Katarzyna; Dejmek, Petr; Panarese, Valentina;

    2012-01-01

    This study explores metabolic responses of germinating barley seeds upon the application of pulsed electric fields (PEF). Malting barley seeds were steeped in aerated water for 24 h and PEF-treated at varying voltages (0 (control), 110, 160, 240, 320, 400 and 480 V). The seeds were then allowed...... to finish germination in saturated air. It is shown that exposure of germinating barley to PEF affects radicle emergence without significantly affecting the seeds’ gross metabolic activity, as quantified by isothermal calorimetry. An exploration of protein 2-DE profiles of both the embryo and the starchy...

  6. Enhanced methane production from pig slurry with pulsed electric field pre-treatment.

    Science.gov (United States)

    Safavi, Seyedeh Masoumeh; Unnthorsson, Runar

    2017-03-08

    Intensive amount of manure produced in pig breeding sectors represents negative impact on the environment and requires optimal management. Anaerobic digestion as a well-known manure management process was optimized in this experimental study by pulsed electric field (PEF) pre-treatment. The effect of PEF on methane production was investigated at three different intensities (15, 30 and 50 kWh/m(3)). The results indicate that the methane production and chemical oxygen demand (COD) removal was improved by continuous escalation of applied intensity, up to 50 kWh/m(3). In comparison with untreated slurry, methane production and COD removal were increased up to 58% and 44%, respectively.

  7. Morphologically Aligned Cation-Exchange Membranes by a Pulsed Electric Field for Reverse Electrodialysis.

    Science.gov (United States)

    Lee, Ju-Young; Kim, Jae-Hun; Lee, Ju-Hyuk; Kim, Seok; Moon, Seung-Hyeon

    2015-07-21

    A low-resistance ion-exchange membrane is essential to achieve the high-performance energy conversion or storage systems. The formation methods for low-resistance membranes are various; one of the methods is the ion channel alignment of an ion-exchange membrane under a direct current (DC) electric field. In this study, we suggest a more effective alignment method than the process with the DC electric field. First, an ion-exchange membrane was prepared under a pulsed electric field [alternating current (AC) mode] to enhance the effectiveness of the alignment. The membrane properties and the performance in reverse electrodialysis (RED) were then examined to assess the membrane resistance and ion selectivity. The results show that the membrane electrical resistance (MER) had a lower value of 0.86 Ω cm(2) for the AC membrane than 2.13 Ω cm(2) observed for the DC membrane and 4.30 Ω cm(2) observed for the pristine membrane. Furthermore, RED achieved 1.34 W/m(2) of maximum power density for the AC membrane, whereas that for the DC membrane was found to be 1.14 W/m(2) [a RED stack assembled with CMX, used as a commercial cation-exchange membrane (CEM), showed 1.07 W/m(2)]. Thereby, the novel preparation process for a remarkable low-resistance membrane with high ion selectivity was demonstrated.

  8. Novel passive element circuits for microdosimetry of nanosecond pulsed electric fields.

    Science.gov (United States)

    Merla, C; Denzi, A; Paffi, A; Casciola, M; d'Inzeo, G; Apollonio, F; Liberti, M

    2012-08-01

    Microdosimetric models for biological cells have assumed increasing significance in the development of nanosecond pulsed electric field technology for medical applications. In this paper, novel passive element circuits, able to take into account the dielectric dispersion of the cell, are provided. The circuital analyses are performed on a set of input pulses classified in accordance with the current literature. Accurate data in terms of transmembrane potential are obtained in both time and frequency domains for different cell models. In addition, a sensitivity study of the transfer function for the cell geometrical and dielectric parameters has been carried out. This analysis offers a new, simple, and efficient tool to characterize the nsPEFs' action at the cellular level.

  9. Transient suppression of gap junctional intercellular communication after exposure to 100-nanosecond pulsed electric fields.

    Science.gov (United States)

    Steuer, Anna; Schmidt, Anke; Labohá, Petra; Babica, Pavel; Kolb, Juergen F

    2016-12-01

    Gap junctional intercellular communication (GJIC) is an important mechanism that is involved and affected in many diseases and injuries. So far, the effect of nanosecond pulsed electric fields (nsPEFs) on the communication between cells was not investigated. An in vitro approach is presented with rat liver epithelial WB-F344 cells grown and exposed in a monolayer. In order to observe sub-lethal effects, cells were exposed to pulsed electric fields with a duration of 100ns and amplitudes between 10 and 20kV/cm. GJIC strongly decreased within 15min after treatment but recovered within 24h. Gene expression of Cx43 was significantly decreased and associated with a reduced total amount of Cx43 protein. In addition, MAP kinases p38 and Erk1/2, involved in Cx43 phosphorylation, were activated and Cx43 became hyperphosphorylated. Immunofluorescent staining of Cx43 displayed the disassembly of gap junctions. Further, a reorganization of the actin cytoskeleton was observed whereas tight junction protein ZO-1 was not significantly affected. All effects were field- and time-dependent and most pronounced within 30 to 60min after treatment. A better understanding of a possible manipulation of GJIC by nsPEFs might eventually offer a possibility to develop and improve treatments.

  10. The Influence of Vesicle Shape and Medium Conductivity on Possible Electrofusion under a Pulsed Electric Field.

    Directory of Open Access Journals (Sweden)

    Linying Liu

    Full Text Available The effects of electric field on lipid membrane and cells have been extensively studied in the last decades. The phenomena of electroporation and electrofusion are of particular interest due to their wide use in cell biology and biotechnology. However, numerical studies on the electrofusion of cells (or vesicles with different deformed shapes are still rare. Vesicle, being of cell size, can be treated as a simple model of cell to investigate the behaviors of cell in electric field. Based on the finite element method, we investigate the effect of vesicle shape on electrofusion of contact vesicles in various medium conditions. The transmembrane voltage (TMV and pore density induced by a pulsed field are examined to analyze the possibility of vesicle fusion. In two different medium conditions, the prolate shape is observed to have selective electroporation at the contact area of vesicles when the exterior conductivity is smaller than the interior one; selective electroporation is more inclined to be found at the poles of the oblate vesicles when the exterior conductivity is larger than the interior one. Furthermore, we find that when the exterior conductivity is lower than the internal conductivity, the pulse can induce a selective electroporation at the contact area between two vesicles regardless of the vesicle shape. Both of these two findings have important practical applications in guiding electrofusion experiments.

  11. The Influence of Vesicle Shape and Medium Conductivity on Possible Electrofusion under a Pulsed Electric Field.

    Science.gov (United States)

    Liu, Linying; Mao, Zheng; Zhang, Jianhua; Liu, Na; Liu, Qing Huo

    2016-01-01

    The effects of electric field on lipid membrane and cells have been extensively studied in the last decades. The phenomena of electroporation and electrofusion are of particular interest due to their wide use in cell biology and biotechnology. However, numerical studies on the electrofusion of cells (or vesicles) with different deformed shapes are still rare. Vesicle, being of cell size, can be treated as a simple model of cell to investigate the behaviors of cell in electric field. Based on the finite element method, we investigate the effect of vesicle shape on electrofusion of contact vesicles in various medium conditions. The transmembrane voltage (TMV) and pore density induced by a pulsed field are examined to analyze the possibility of vesicle fusion. In two different medium conditions, the prolate shape is observed to have selective electroporation at the contact area of vesicles when the exterior conductivity is smaller than the interior one; selective electroporation is more inclined to be found at the poles of the oblate vesicles when the exterior conductivity is larger than the interior one. Furthermore, we find that when the exterior conductivity is lower than the internal conductivity, the pulse can induce a selective electroporation at the contact area between two vesicles regardless of the vesicle shape. Both of these two findings have important practical applications in guiding electrofusion experiments.

  12. Histopathology of normal skin and melanomas after nanosecond pulsed electric field treatment.

    Science.gov (United States)

    Chen, Xinhua; James Swanson, R; Kolb, Juergen F; Nuccitelli, Richard; Schoenbach, Karl H

    2009-12-01

    Nanosecond pulsed electric fields (nsPEFs) can affect the intracellular structures of cells in vitro. This study shows the direct effects of nsPEFs on tumor growth, tumor volume, and histological characteristics of normal skin and B16-F10 melanoma in SKH-1 mice. A melanoma model was set up by injecting B16-F10 into female SKH-1 mice. After a 100-pulse treatment with an nsPEF (40-kV/cm field strength; 300-ns duration; 30-ns rise time; 2-Hz repetition rate), tumor growth and histology were studied using transillumination, light microscopy with hematoxylin and eosin stain and transmission electron microscopy. Melanin and iron within the melanoma tumor were also detected with specific stains. After nsPEF treatment, tumor development was inhibited with decreased volumes post-nsPEF treatment compared with control tumors (Pcell contraction and nuclear shrinkage while concurrently, but not permanently, damaging peripheral healthy skin tissue in the treated area, which we attribute to the highly localized electric fields surrounding the needle electrodes.

  13. The Influence of Vesicle Shape and Medium Conductivity on Possible Electrofusion under a Pulsed Electric Field

    Science.gov (United States)

    Liu, Linying; Mao, Zheng; Zhang, Jianhua; Liu, Na; Liu, Qing Huo

    2016-01-01

    The effects of electric field on lipid membrane and cells have been extensively studied in the last decades. The phenomena of electroporation and electrofusion are of particular interest due to their wide use in cell biology and biotechnology. However, numerical studies on the electrofusion of cells (or vesicles) with different deformed shapes are still rare. Vesicle, being of cell size, can be treated as a simple model of cell to investigate the behaviors of cell in electric field. Based on the finite element method, we investigate the effect of vesicle shape on electrofusion of contact vesicles in various medium conditions. The transmembrane voltage (TMV) and pore density induced by a pulsed field are examined to analyze the possibility of vesicle fusion. In two different medium conditions, the prolate shape is observed to have selective electroporation at the contact area of vesicles when the exterior conductivity is smaller than the interior one; selective electroporation is more inclined to be found at the poles of the oblate vesicles when the exterior conductivity is larger than the interior one. Furthermore, we find that when the exterior conductivity is lower than the internal conductivity, the pulse can induce a selective electroporation at the contact area between two vesicles regardless of the vesicle shape. Both of these two findings have important practical applications in guiding electrofusion experiments. PMID:27391692

  14. Elasticity and tumorigenic characteristics of cells in a monolayer after nanosecond pulsed electric field exposure.

    Science.gov (United States)

    Steuer, A; Wende, K; Babica, P; Kolb, J F

    2017-09-01

    Nanosecond pulsed electric fields (nsPEFs) applied to cells can induce different biological effects depending on pulse duration and field strength. One known process is the induction of apoptosis whereby nsPEFs are currently investigated as a novel cancer therapy. Another and probably related change is the breakdown of the cytoskeleton. We investigated the elasticity of rat liver epithelial cells WB-F344 in a monolayer using atomic force microscopy (AFM) with respect to the potential of cells to undergo malignant transformation or to develop a potential to metastasize. We found that the elastic modulus of the cells decreased significantly within the first 8 min after treatment with 20 pulses of 100 ns and with a field strength of 20 kV/cm but was still higher than the elasticity of their tumorigenic counterpart WB-ras. AFM measurements and immunofluorescent staining showed that the cellular actin cytoskeleton became reorganized within 5 min. However, both a colony formation assay and a cell migration assay revealed no significant changes after nsPEF treatment, implying that cells seem not to adopt malignant characteristics associated with metastasis formation despite the induced transient changes to elasticity and cytoskeleton that can be observed for up to 1 h.

  15. Calcium influx affects intracellular transport and membrane repair following nanosecond pulsed electric field exposure.

    Science.gov (United States)

    Thompson, Gary Lee; Roth, Caleb C; Dalzell, Danielle R; Kuipers, Marjorie; Ibey, Bennett L

    2014-05-01

    The cellular response to subtle membrane damage following exposure to nanosecond pulsed electric fields (nsPEF) is not well understood. Recent work has shown that when cells are exposed to nsPEF, ion permeable nanopores (2  nm) created by longer micro- and millisecond duration pulses. Nanoporation of the plasma membrane by nsPEF has been shown to cause a transient increase in intracellular calcium concentration within milliseconds after exposure. Our research objective is to determine the impact of nsPEF on calcium-dependent structural and repair systems in mammalian cells. Chinese hamster ovary (CHO-K1) cells were exposed in the presence and absence of calcium ions in the outside buffer to either 1 or 20, 600-ns duration electrical pulses at 16.2  kV/cm, and pore size was determined using propidium iodide and calcium green. Membrane organization was observed with morphological changes and increases in FM1-43 fluorescence. Migration of lysosomes, implicated in membrane repair, was followed using confocal microscopy of red fluorescent protein-tagged LAMP1. Microtubule structure was imaged using mEmerald-tubulin. We found that at high 600-ns PEF dosage, calcium-induced membrane restructuring and microtubule depolymerization coincide with interruption of membrane repair via lysosomal exocytosis.

  16. Outlook for the use of focused shock waves and pulsed electric fields in the complex treatment of malignant neoplasms.

    Science.gov (United States)

    Garilevich, B A; Andrianov, Yu V; Olefir, Yu V; Zubkov, A D; Rotov, A E

    2006-01-01

    The experimental studies the synchronous action of electric field microsecond range with amplitude within the range of 1-7 kV/sm and shock waves with pressure before 100 MPa on cells membrane permeability of the mouse's ascitic tumors in vitro have shown the intensification the efficiency of the forming the irreversible pores under synchronous action. Thereby, enabling the electric field in the compression phase of shock wave pulse which can essentially reduce the electric field intensity required for breakdown cell membrane. In usual condition at amplitude of electric field, specified above, electric breakdown membrane carries basically reversible nature. At the same time in the pressure field tension phase of shock-wave pulse reversible pores, created by electric field, can grow before sizes, under which wholeness membrane is not restored. Under simultaneous action on cellular suspension the shock wave and electric field with moderate intensity cells survival is reduced in 5 once in contrast with occuring at different time's action, and in 10 once in contrast with checking. The most sensitive to influence by under study fields are cells in phase of the syntheses DNA, preparation to fission and in phase of the mitosis. Thereby, continuation of the studies on use synchronous action shock waves and pulsed electric fields in complex treatment of the tumors introduces perspective.

  17. Numerical evaluation of lactoperoxidase inactivation during continuous pulsed electric field processing.

    Science.gov (United States)

    Buckow, Roman; Semrau, Julius; Sui, Qian; Wan, Jason; Knoerzer, Kai

    2012-01-01

    A computational fluid dynamics (CFD) model describing the flow, electric field and temperature distribution of a laboratory-scale pulsed electric field (PEF) treatment chamber with co-field electrode configuration was developed. The predicted temperature increase was validated by means of integral temperature studies using thermocouples at the outlet of each flow cell for grape juice and salt solutions. Simulations of PEF treatments revealed intensity peaks of the electric field and laminar flow conditions in the treatment chamber causing local temperature hot spots near the chamber walls. Furthermore, thermal inactivation kinetics of lactoperoxidase (LPO) dissolved in simulated milk ultrafiltrate were determined with a glass capillary method at temperatures ranging from 65 to 80 °C. Temperature dependence of first order inactivation rate constants was accurately described by the Arrhenius equation yielding an activation energy of 597.1 kJ mol(-1). The thermal impact of different PEF processes on LPO activity was estimated by coupling the derived Arrhenius model with the CFD model and the predicted enzyme inactivation was compared to experimental measurements. Results indicated that LPO inactivation during combined PEF/thermal treatments was largely due to thermal effects, but 5-12% enzyme inactivation may be related to other electro-chemical effects occurring during PEF treatments.

  18. Nanosecond pulsed electric field thresholds for nanopore formation in neural cells.

    Science.gov (United States)

    Roth, Caleb C; Tolstykh, Gleb P; Payne, Jason A; Kuipers, Marjorie A; Thompson, Gary L; DeSilva, Mauris N; Ibey, Bennett L

    2013-03-01

    The persistent influx of ions through nanopores created upon cellular exposure to nanosecond pulse electric fields (nsPEF) could be used to modulate neuronal function. One ion, calcium (Ca(2+)), is important to action potential firing and regulates many ion channels. However, uncontrolled hyper-excitability of neurons leads to Ca(2+) overload and neurodegeneration. Thus, to prevent unintended consequences of nsPEF-induced neural stimulation, knowledge of optimum exposure parameters is required. We determined the relationship between nsPEF exposure parameters (pulse width and amplitude) and nanopore formation in two cell types: rodent neuroblastoma (NG108) and mouse primary hippocampal neurons (PHN). We identified thresholds for nanoporation using Annexin V and FM1-43, to detect changes in membrane asymmetry, and through Ca(2+) influx using Calcium Green. The ED50 for a single 600 ns pulse, necessary to cause uptake of extracellular Ca(2+), was 1.76  kV/cm for NG108 and 0.84  kV/cm for PHN. At 16.2  kV/cm, the ED50 for pulse width was 95 ns for both cell lines. Cadmium, a nonspecific Ca(2+) channel blocker, failed to prevent Ca(2+) uptake suggesting that observed influx is likely due to nanoporation. These data demonstrate that moderate amplitude single nsPEF exposures result in rapid Ca(2+) influx that may be capable of controllably modulating neurological function.

  19. Selective susceptibility to nanosecond pulsed electric field (nsPEF) across different human cell types.

    Science.gov (United States)

    Gianulis, Elena C; Labib, Chantelle; Saulis, Gintautas; Novickij, Vitalij; Pakhomova, Olga N; Pakhomov, Andrei G

    2017-05-01

    Tumor ablation by nanosecond pulsed electric fields (nsPEF) is an emerging therapeutic modality. We compared nsPEF cytotoxicity for human cell lines of cancerous (IMR-32, Hep G2, HT-1080, and HPAF-II) and non-cancerous origin (BJ and MRC-5) under strictly controlled and identical conditions. Adherent cells were uniformly treated by 300-ns PEF (0-2000 pulses, 1.8 kV/cm, 50 Hz) on indium tin oxide-covered glass coverslips, using the same media and serum. Cell survival plotted against the number of pulses displayed three distinct regions (initial resistivity, logarithmic survival decline, and residual resistivity) for all tested cell types, but with differences in LD50 spanning as much as nearly 80-fold. The non-cancerous cells were less sensitive than IMR-32 neuroblastoma cells but more vulnerable than the other cancers tested. The cytotoxic efficiency showed no apparent correlation with cell or nuclear size, cell morphology, metabolism level, or the extent of membrane disruption by nsPEF. Increasing pulse duration to 9 µs (0.75 kV/cm, 5 Hz) produced a different selectivity pattern, suggesting that manipulation of PEF parameters can, at least for certain cancers, overcome their resistance to nsPEF ablation. Identifying mechanisms and cell markers of differential nsPEF susceptibility will critically contribute to the proper choice and outcome of nsPEF ablation therapies.

  20. Isolated attosecond pulses generation from coherent superposition state of helium ion in static electric fields and spatial nonhomogeneous fields

    Science.gov (United States)

    Liu, Hao; Zhang, Zhengzhong; Wu, Yangjiang; Jiang, Shicheng; Yu, Chao

    2016-09-01

    We present a systematic study of high-order harmonic generation (HHG) from helium ion with the initial state prepared as a coherent superposition of electronic ground state and an excited state. As a result, the conversion efficiency of the harmonic spectrum is significantly enhanced. When we add a static electric field in fundamental field, the supercontinuum region of the harmonic spectrum is distinctly extended and an isolated 100 as pulse can be generated. Moreover, we use a spatial nonhomogeneous field to increase the cutoff energy in high-order harmonic generation spectrum, which can be extended to about 700 eV, and an isolated 50 as pulse can be obtained directly by the superposition of the supercontinuum harmonics.

  1. Impact of high-intensity pulsed electric fields on carotenoids profile of tomato juice made of moderate-intensity pulsed electric field-treated tomatoes.

    Science.gov (United States)

    Vallverdú-Queralt, Anna; Odriozola-Serrano, Isabel; Oms-Oliu, Gemma; Lamuela-Raventós, Rosa M; Elez-Martínez, Pedro; Martín-Belloso, Olga

    2013-12-01

    The effect of pulsed electric fields (PEF) on the carotenoid content of tomato juices was studied. First, moderate-intensity PEF (MIPEF) was applied to raw tomatoes. Afterwards, MIPEF-treated and untreated tomatoes were immediately refrigerated at 4 °C for 24 h and then, they were separately ground to produce tomato juices. Juices were treated by heat treatments or by high-intensity PEF (HIPEF) and stored under refrigeration for 56 days. MIPEF treatment of tomatoes increased the content of carotenoid compounds in tomato juices. An enhancement of 63-65% in 15-cis-lycopene was observed in juices prepared with MIPEF-treated tomatoes. A slight increase in cis-lycopene isomers was observed over time, whereas other carotenoids slightly decreased. However, HIPEF treated tomato juices maintained higher carotenoid content (10-20%) through the storage time than thermally and untreated juices. The combination of MIPEF and HIPEF treatments could be used not only to produce tomato juices with high carotenoid content but also, to maintain higher the carotenoid content during storage time.

  2. Evaluation of cell-disruption effects of pulsed-electric-field treatment of Synechocystis PCC 6803.

    Science.gov (United States)

    Sheng, Jie; Vannela, Raveender; Rittmann, Bruce E

    2011-04-15

    In order to use Synechocystis PCC 6803 as feedstock of nonpetroleum-based diesel fuel, pulsed electric field (PEF) technology was used for cell disruption prior to extraction of intracellular lipids. Severe cell disruption was evident after PEF treatment, especially with treatment intensity (TI) > 35 kWh/m(3). Temperature increase during the treatment brought about most of the destruction of autofluorescence compounds, as well as a fraction of inactivation and the destruction of the plasma and thylakoid membranes. However, the forces associated with the pulsing electric field caused significant damage to the plasma membrane, cell wall, and thylakoid membrane, and it even led to complete disruption of some cells into fragments, which resulted in biomass loss. Treatment by PEF enhanced the potential for the low-toxicity solvent isopropanol to access lipid molecules during subsequent solvent extraction, leading to lower usage of isopropanol for the same extraction efficiency. Thus, PEF shows promise for lowering the costs and environmental effects of the lipid-extraction step.

  3. Analysis of DPPH inhibition and structure change of corn peptides treated by pulsed electric field technology.

    Science.gov (United States)

    Wang, Ke; Wang, Ying; Lin, Songyi; Liu, Xuye; Yang, Shuailing; Jones, Gregory S

    2015-07-01

    In this study, the effects on antioxidant activity and structure change of corn peptides (CPS) with 10 to 30 kDa molecular weight (MW) treated by pulsed electric field (PEF) technology were investigated. 2, 2-diphenyl-1-picrylhydrazyl (DPPH) inhibition was used to evaluate the antioxidant activity of CPS. Response surface methodology (RSM) was used to investigate the effects of PEF treatment parameters on antioxidant activity of CPS. The optimal conditions were as follows: concentration of CPS 10 mg mL(-1), electric field intensity 15 kV cm(-1), and pulse frequency 2,000 Hz. Under the optimized conditions, the DPPH inhibition of CPS increased 32.1 %, compared to the sample untreated. And mid-infrared spectroscopy (MIR) was used for analyzing the structure change of CPS. The results showed that PEF technology could obviously increase the DPPH inhibition of CPS under the optimized conditions (P < 0.05).

  4. Pulsed electric field pretreatment of rapeseed green biomass (stems) to enhance pressing and extractives recovery.

    Science.gov (United States)

    Yu, X; Gouyo, T; Grimi, N; Bals, O; Vorobiev, E

    2016-01-01

    The objective of this study was to investigate the effects of pulsed electric field (PEF) pretreatment on the valorization of extractives (proteins and polyphenols) from rapeseed green biomass (stems) by pressing. The effect of pressure, electric field strength and pulse number on the juice expression yield, total polyphenols and total proteins content in the expressed juices were studied. Experiments conducted under optimal conditions (E = 8 kV/cm, tPEF = 2 ms, P = 10 bar) permitted to increase the juice expressed yield from 34% to 81%. Significant increases in total polyphenols content (0.48 vs. 0.10 g GAE/100g DM), in total proteins content (0.14 vs. 0.07 g BSA/100g DM) and in consolidation coefficient (9.0 × 10(-8) vs. 2.2 × 10(-8)m(2)/s) were also observed after PEF pretreatment. The recovered press cake was well dehydrated with an increase of dry matter content from 8.8% to 53.0%.

  5. COMBINING MODERATE PULSED ELECTRIC FIELDS WITH TEMPERATURE AND WITH ORGANIC ACIDS TO INACTIVATE ESCHERICHIA COLI SUSPENSIONS

    Directory of Open Access Journals (Sweden)

    Henri EL ZAKHEM

    2010-09-01

    Full Text Available The aim of this work was to study the efficiency of inactivation of Escherichia coli cells in aqueous suspensions using combined moderate pulsed electric field (PEF and thermal treatments. The inactivation kinetics of E. coli cells in aqueous suspensions (1 wt% was monitored using conductometric technique. The electric field strength E was within 5-7.5 kV/cm, the effective PEF treatment time was within 0-0.75 s, the pulse duration ti was within 0.3-1 ms, the medium temperature was 30-50°C, and the time of thermal treatment tT was within 0-7000 s. The organic acid concentration was within 0-0.5 g/L.The damage of E. coli was accompanied by release of intracellular components. The synergy between the PEF and thermal treatments in E. coli inactivation was clearly demonstrated. The damage efficiency was noticeably improved by addition of organic acids, especially lactic acid.

  6. Enhanced electroporation in plant tissues via low frequency pulsed electric fields: influence of cytoplasmic streaming.

    Science.gov (United States)

    Asavasanti, Suvaluk; Stroeve, Pieter; Barrett, Diane M; Jernstedt, Judith A; Ristenpart, William D

    2012-01-01

    Pulsed electric fields (PEF) are known to be effective at permeabilizing plant tissues. Prior research has demonstrated that lower pulse frequencies induce higher rates of permeabilization, but the underlying reason for this response is unclear. Intriguingly, recent microscopic observations with onion tissues have also revealed a correlation between PEF frequency and the subsequent speed of intracellular convective motion, i.e., cytoplasmic streaming. In this paper, we investigate the effect of cytoplasmic streaming on the efficacy of plant tissue permeabilization via PEF. Onion tissue samples were treated with Cytochalasin B, a known inhibitor of cytoplasmic streaming, and changes in cellular integrity and viability were measured over a wide range of frequencies and field strengths. We find that at low frequencies (f streaming results in a 19% decrease in the conductivity disintegration index compared with control samples. Qualitatively, similar results were observed using a microscopic cell viability assay. The results suggest that at low frequencies convection plays a statistically significant role in distributing more conductive fluid throughout the tissue, making subsequent pulses more efficacious. The key practical implication is that PEF pretreatment at low frequency can increase the rate of tissue permeabilization in dehydration or extraction processes, and that the treatment will be most effective when cytoplasmic streaming is most active, i.e., with freshly prepared plant tissues.

  7. [Fluorescence polarization used to investigate the cell membrane fluidity of Saccharomyces cerevisiae treated by pulsed electric field].

    Science.gov (United States)

    Zhang, Ying; Zeng, Xin-An; Wen, Qi-Biao; Li, Lin

    2008-01-01

    To know the lethal mechanism of microorganisms under pulsed electric field treatment, the relationship between the inactivation of Saccharomyces cerevisiae (CICC1308) cell and the permeability and fluidity changes of its cell membrane treated by pulsed electric field (0-25 kV x cm(-1), 0-266 ms) was investigated. With 1,6-diphenyl-1,3,5-hexatriene (DPH) used as a probe, the cell membrane fluidity of Saccharomyces cerevisiae treated by pulsed electric field was expressed by fluorescence polarization. Results showed that the cell membrane fluidity decreases when the electric flied strength is up to 5 kV x cm(-1), and decreases with the increase in electric field strength and treatment time. The plate counting method and ultraviolet spectrophotometer were used to determine the cell viability and to investigate the cell membrane permeability, respectively, treated by pulsed electric field. Results showed that the lethal ratio and the content of protein and nucleic acid leaked from intracellular plasma increased with the increase in the electric field strength and the extension of treatment time. Even in a quite lower electric field of 5 kV x cm(-1) with a tiny microorganism lethal level, the increase in UV absorption value and the decrease in fluidity were significant. It was demonstrated that the cell membrane fluidity decreases with the increase in lethal ratio and cell membrane permeability. The viscosity of cell membrane increases with the decrease in fluidity. These phenomena indicated that cell membrane is one of the most key sites during the pulsed electric field treatment, and the increased membrane permeability and the decreased cell membrane fluidity contribute to the cell death.

  8. Combination of microsecond and nanosecond pulsed electric field treatments for inactivation of Escherichia coli in water samples.

    Science.gov (United States)

    Žgalin, Maj Kobe; Hodžić, Duša; Reberšek, Matej; Kandušer, Maša

    2012-10-01

    Inactivation of microorganisms with pulsed electric fields is one of the nonthermal methods most commonly used in biotechnological applications such as liquid food pasteurization and water treatment. In this study, the effects of microsecond and nanosecond pulses on inactivation of Escherichia coli in distilled water were investigated. Bacterial colonies were counted on agar plates, and the count was expressed as colony-forming units per milliliter of bacterial suspension. Inactivation of bacterial cells was shown as the reduction of colony-forming units per milliliter of treated samples compared to untreated control. According to our results, when using microsecond pulses the level of inactivation increases with application of more intense electric field strengths and with number of pulses delivered. Almost 2-log reductions in bacterial counts were achieved at a field strength of 30 kV/cm with eight pulses and a 4.5-log reduction was observed at the same field strength using 48 pulses. Extending the duration of microsecond pulses from 100 to 250 μs showed no improvement in inactivation. Nanosecond pulses alone did not have any detectable effect on inactivation of E. coli regardless of the treatment time, but a significant 3-log reduction was achieved in combination with microsecond pulses.

  9. External stimulation by nanosecond pulsed electric fields to enhance cellular uptake of nanoparticles

    Science.gov (United States)

    Franklin, Samantha; Beier, Hope T.; Ibey, Bennett L.; Nash, Kelly

    2015-03-01

    As an increasing number of studies use gold nanoparticles (AuNPs) for potential medicinal, biosensing and therapeutic applications, the synthesis and use of readily functional, bio-compatible nanoparticles is receiving much interest. For these efforts, the particles are often taken up by the cells to allow for optimum sensing or therapeutic measures. This process typically requires incubation of the particles with the cells for an extended period. In an attempt to shorten and control this incubation, we investigated whether nanosecond pulsed electric field (nsPEF) exposure of cells will cause a controlled uptake of the particles. NsPEF are known to induce the formation of nanopores in the plasma membrane, so we hypothesized that by controlling the number, amplitude or duration of the nsPEF exposure, we could control the size of the nanopores, and thus control the particle uptake. Chinese hamster ovary (CHO-K1) cells were incubated sub-10 nm AuNPs with and without exposure to 600-ns electrical pulses. Contrary to our hypothesis, the nsPEF exposure was found to actually decrease the particle uptake in the exposed cells. This result suggests that the nsPEF exposure may be affecting the endocytotic pathway and processes due to membrane disruption.

  10. Permeabilization of the nuclear envelope following nanosecond pulsed electric field exposure.

    Science.gov (United States)

    Thompson, Gary L; Roth, Caleb C; Kuipers, Marjorie A; Tolstykh, Gleb P; Beier, Hope T; Ibey, Bennett L

    2016-01-29

    Permeabilization of cell membranes occurs upon exposure to a threshold absorbed dose (AD) of nanosecond pulsed electric fields (nsPEF). The ultimate, physiological bioeffect of this exposure depends on the type of cultured cell and environment, indicating that cell-specific pathways and structures are stimulated. Here we investigate 10 and 600 ns duration PEF effects on Chinese hamster ovary (CHO) cell nuclei, where our hypothesis is that pulse disruption of the nuclear envelope membrane leads to observed cell death and decreased viability 24 h post-exposure. To observe short-term responses to nsPEF exposure, CHO cells have been stably transfected with two fluorescently-labeled proteins known to be sequestered for cellular chromosomal function within the nucleus - histone-2b (H2B) and proliferating cell nuclear antigen (PCNA). H2B remains associated with chromatin after nsPEF exposure, whereas PCNA leaks out of nuclei permeabilized by a threshold AD of 10 and 600 ns PEF. A downturn in 24 h viability, measured by MTT assay, is observed at the number of pulses required to induce permeabilization of the nucleus.

  11. Combination pulsed electric field with ethanol solvent for Nannochloropsis sp. extraction

    Science.gov (United States)

    Nafis, Ghazy Ammar; Mumpuni, Perwitasari Yekti; Indarto, Budiman, Arief

    2015-12-01

    Nowadays, energy is one of human basic needs. As the human population increased, energy consumption also increased. This condition causes energy depletion. In case of the situation, alternative energy is needed to replace existing energy. Microalgae is chosen to become one of renewable energy resource, especially biodiesel, because it contains high amount of lipid instead of other feedstock which usually used. Fortunately, Indonesia has large area of water and high intensity of sunlight so microalgae cultivation becomes easier. Nannochloropsis sp., one of microalgae species, becomes the main focus because of its high lipid content. Many ways to break the cell wall of microalgae so the lipid content inside the microalgae will be released, for example conventional extraction, ultrasonic wave extraction, pressing, and electrical method. The most effective way for extraction is electrical method such as pulsed electric field method (PEF). The principal work of this method is by draining the electrical current into parallel plate. Parallel plate will generate the electrical field to break microalgae cell wall and the lipid will be released. The aim of this work is to evaluate two-stage procedure for extraction of useful components from microalgae Nannochloropsis sp. The first stage of this procedure includes pre-treatment of microalgae by ethanol solvent extraction and the second stage applies the PEF extraction using a binary mixture of water and ethanol solvent. Ethanol is chosen as solvent because it's safer to be used and easier to be handled than other solvent. Some variables that used to study the most effective operation conditions are frequency and duty cycle for microalgae. The optimum condition based on this research are at frequency 1 Hz and duty cycle 13%.

  12. Quality stability and sensory attributes of apple juice processed by thermosonication, pulsed electric field and thermal processing.

    Science.gov (United States)

    Sulaiman, Alifdalino; Farid, Mohammed; Silva, Filipa Vm

    2017-04-01

    Worldwide, apple juice is the second most popular juice, after orange juice. It is susceptible to enzymatic browning spoilage by polyphenoloxidase, an endogenous enzyme. In this study, Royal Gala apple juice was treated by thermosonication (TS: 1.3 W/mL, 58 ℃, 10 min), pulsed electric field (PEF: 24.8 kV/cm, 60 pulses, 169 µs treatment time, 53.8 ℃) and heat (75 ℃, 20 min) and stored at 3.0 ℃ and 20.0 ℃ for 30 days. A sensory analysis was carried out after processing. The polyphenoloxidase activity, antioxidant activity and total color difference of the apple juice were determined before and after processing and during storage. The sensory analysis revealed that thermosonication and pulsed electric field juices tasted differently from the thermally treated juice. Apart from the pulsed electric field apple juice stored at room temperature, the processed juice was stable during storage, since the pH and soluble solids remained constant and fermentation was not observed. Polyphenoloxidase did not reactivate during storage. Along storage, the juices' antioxidant activity decreased and total color difference increased (up to 6.8). While the antioxidant activity increased from 86 to 103% with thermosonication and was retained after pulsed electric field, thermal processing reduced it to 67%. The processing increased the total color difference slightly. No differences in the total color difference of the juices processed by the three methods were registered after storage. Thermosonication and pulsed electric field could possibly be a better alternative to thermal preservation of apple juice, but refrigerated storage is recommended for pulsed electric field apple juice.

  13. Electric Field Stress Simulation of Plasma Membrane Under Steep Pulsed Electric Field%陡脉冲电场作用下细胞电场力的仿真计算

    Institute of Scientific and Technical Information of China (English)

    姚陈果; 罗霄; 李成祥

    2009-01-01

    The basic characteristic of electric field is that the substance in the field is in operation by the stress.Under external electric fields,there is strong distribution of electric fields on the inside and outside surfaces of cell membrane.In virtue of the difference of the permittivity among membrane,cytoplasm and extracellular medium,there must he electric field stress on the surface of the membrane.The goal of the study is to research the irreversible electrical breakdown (IRE) mechanism of the malignant tumor cells under steep pulsed electric field (SPEF) from the views of mechanics.Electric field stress of plasma membrane under steep pulsed electric field is calculated and simulated both on malignant tumor cells and on the normal cells.The calculation results show that,in addition to a compressive stress normal to the membrane plane,transverse traction stresses are generated in the lateral plane of the membrane.The lateral stress will reduce the membrane tension significantly,leading to electroporation and rupture.At the same electric field strength,the transverse traction stress on malignant cell membrane is greatly larger than the one on normal cell membrane.Therefore,compared with the normal cells,the malignant tumor cells are more sensitive under the steep pulsed electric field.Namely,steep pulsed electric field can selectively destroy the malignant tumor cells,which proved the safety of treating malignant tumors by steep pulsed electric field.

  14. Reducing Viscosity of Liquid Suspensions by pulsed electric or magnetic field

    Science.gov (United States)

    Tao, R.

    2007-03-01

    Viscosity of liquid suspensions is of great importance. Controlling the viscosity is vital in science and engineering. In electrorheological (ER) or magentorheological (MR) fluids, electric or magnetic field is used to increase the viscosity. However, in most cases we need to lower the viscosity. For example, reducing blood's viscosity improves circulation and prevents cardiovascular events. Lowering the viscosity of crude oil is the key to transporting offshore oil via undersea pipelines. Unfortunately, to date there are no effective methods for reducing the viscosity except by changing the temperature. In case that changing temperature is not an option, such as in the above examples, reducing the viscosity becomes formidable. Here we present a theory and experimental results showing that application of a suitable electric or magnetic field pulse can significantly reduce the viscosity of liquid suspensions for several hours with no change of temperature. The field induces dipolar interactions between the suspended particles and forces them to aggregate into large particles. The aggregation changes the rheological properties of the fluids and reduces the effective viscosity. Positive experimental results with MR fluids and crude oil indicate that this method, developed from the basic mechanism of viscosity, is universal and powerful for all liquid suspensions with broad applications.

  15. Two modes of cell death caused by exposure to nanosecond pulsed electric field.

    Directory of Open Access Journals (Sweden)

    Olga N Pakhomova

    Full Text Available High-amplitude electric pulses of nanosecond duration, also known as nanosecond pulsed electric field (nsPEF, are a novel modality with promising applications for cell stimulation and tissue ablation. However, key mechanisms responsible for the cytotoxicity of nsPEF have not been established. We show that the principal cause of cell death induced by 60- or 300-ns pulses in U937 cells is the loss of the plasma membrane integrity ("nanoelectroporation", leading to water uptake, cell swelling, and eventual membrane rupture. Most of this early necrotic death occurs within 1-2 hr after nsPEF exposure. The uptake of water is driven by the presence of pore-impermeable solutes inside the cell, and can be counterbalanced by the presence of a pore-impermeable solute such as sucrose in the medium. Sucrose blocks swelling and prevents the early necrotic death; however the long-term cell survival (24 and 48 hr does not significantly change. Cells protected with sucrose demonstrate higher incidence of the delayed death (6-24 hr post nsPEF. These cells are more often positive for the uptake of an early apoptotic marker dye YO-PRO-1 while remaining impermeable to propidium iodide. Instead of swelling, these cells often develop apoptotic fragmentation of the cytoplasm. Caspase 3/7 activity increases already in 1 hr after nsPEF and poly-ADP ribose polymerase (PARP cleavage is detected in 2 hr. Staurosporin-treated positive control cells develop these apoptotic signs only in 3 and 4 hr, respectively. We conclude that nsPEF exposure triggers both necrotic and apoptotic pathways. The early necrotic death prevails under standard cell culture conditions, but cells rescued from the necrosis nonetheless die later on by apoptosis. The balance between the two modes of cell death can be controlled by enabling or blocking cell swelling.

  16. Two modes of cell death caused by exposure to nanosecond pulsed electric field.

    Science.gov (United States)

    Pakhomova, Olga N; Gregory, Betsy W; Semenov, Iurii; Pakhomov, Andrei G

    2013-01-01

    High-amplitude electric pulses of nanosecond duration, also known as nanosecond pulsed electric field (nsPEF), are a novel modality with promising applications for cell stimulation and tissue ablation. However, key mechanisms responsible for the cytotoxicity of nsPEF have not been established. We show that the principal cause of cell death induced by 60- or 300-ns pulses in U937 cells is the loss of the plasma membrane integrity ("nanoelectroporation"), leading to water uptake, cell swelling, and eventual membrane rupture. Most of this early necrotic death occurs within 1-2 hr after nsPEF exposure. The uptake of water is driven by the presence of pore-impermeable solutes inside the cell, and can be counterbalanced by the presence of a pore-impermeable solute such as sucrose in the medium. Sucrose blocks swelling and prevents the early necrotic death; however the long-term cell survival (24 and 48 hr) does not significantly change. Cells protected with sucrose demonstrate higher incidence of the delayed death (6-24 hr post nsPEF). These cells are more often positive for the uptake of an early apoptotic marker dye YO-PRO-1 while remaining impermeable to propidium iodide. Instead of swelling, these cells often develop apoptotic fragmentation of the cytoplasm. Caspase 3/7 activity increases already in 1 hr after nsPEF and poly-ADP ribose polymerase (PARP) cleavage is detected in 2 hr. Staurosporin-treated positive control cells develop these apoptotic signs only in 3 and 4 hr, respectively. We conclude that nsPEF exposure triggers both necrotic and apoptotic pathways. The early necrotic death prevails under standard cell culture conditions, but cells rescued from the necrosis nonetheless die later on by apoptosis. The balance between the two modes of cell death can be controlled by enabling or blocking cell swelling.

  17. Effect of Twisted Fiber Anisotropy in Cardiac Tissue on Ablation with Pulsed Electric Fields

    Science.gov (United States)

    Xie, Fei; Zemlin, Christian W.

    2016-01-01

    Background Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart. Methods We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered how tissue thickness, degree of anisotropy, and electrode configuration affect the geometry of the ablated volume. We considered two electrode configurations: two parallel needles inserted into the myocardium (“penetrating needles” configuration) and one circular electrode each on epi- and endocardium, opposing each other (“epi-endo” configuration). Results For thick tissues (10 mm) and moderate anisotropy ratio (a = 2), we find that the geometry of the ablated volume is almost unaffected by twisted anisotropy, i.e. it is approximately translationally symmetric from epi- to endocardium, for both electrode configurations. Higher anisotropy ratio (a = 10) leads to substantial variation in ablation width across the wall; these variations were more pronounced for the penetrating needle configuration than for the epi-endo configuration. For thinner tissues (4 mm, typical for human atria) and higher anisotropy ratio (a = 10), the epi-endo configuration yielded approximately translationally symmetric ablation volumes, while the penetrating electrodes configuration was much more sensitive to fiber twist. Conclusions These results suggest that the epi-endo configuration will be reliable for ablation of atrial fibrillation, independently of fiber orientation, while the penetrating electrode configuration may experience problems when the

  18. Neurostimulation using subnanosecond electric pulses

    Science.gov (United States)

    Xiao, Shu; Pakhomov, Andrei; Guo, Fei; Polisetty, Swetha; Schoenbach, Karl H.

    2013-02-01

    We have for the first time recorded action potentials in rat hippocampus neurons when they were stimulated by subnanosecond electric pulses. The preliminary results show that applying a series of pulses allowed the accumulation of depolarization before activating the voltage gated channels. The depolarization only occurred when the electric pulses were applied. It is unclear whether the depolarization is caused by the charge accumulation across the membrane or the cation influx due to the membrane permeabilization. We have also conducted an electromagnetic simulation of delivering subnanosecond pulses to tissues using an impulse radiating antenna. The results show that the pulses can be confined in the deep region in the brain but the amplitude is reduced significantly due to the attenuation of the tissues. A partially lossy dielectric lens may be used to reverse the decreasing trend of the electric field.

  19. Eradication of multidrug-resistant A. baumannii in burn wounds by antiseptic pulsed electric field.

    Science.gov (United States)

    Golberg, Alexander; Broelsch, G Felix; Vecchio, Daniela; Khan, Saiqa; Hamblin, Michael R; Austen, William G; Sheridan, Robert L; Yarmush, Martin L

    2014-06-01

    Emerging bacterial resistance to multiple drugs is an increasing problem in burn wound management. New non-pharmacologic interventions are needed for burn wound disinfection. Here we report on a novel physical method for disinfection: antiseptic pulsed electric field (PEF) applied externally to the infected burns. In a mice model, we show that PEF can reduce the load of multidrug resistant Acinetobacter baumannii present in a full thickness burn wound by more than four orders of magnitude, as detected by bioluminescence imaging. Furthermore, using a finite element numerical model, we demonstrate that PEF provides non-thermal, homogeneous, full thickness treatment for the burn wound, thus, overcoming the limitation of treatment depth for many topical antimicrobials. These modeling tools and our in vivo results will be extremely useful for further translation of the PEF technology to the clinical setting, as they provide the essential elements for planning of electrode design and treatment protocol.

  20. Spectral representation of the particle production out of equilibrium - Schwinger mechanism in pulsed electric fields

    CERN Document Server

    Fukushima, Kenji

    2014-01-01

    We develop a formalism to describe the particle production out of equilibrium in terms of dynamical spectral functions, i.e. Wigner transformed Pauli-Jordan's and Hadamard's functions. We take an explicit example of a spatially homogeneous scalar theory under pulsed electric fields and investigate the time evolution of the spectral functions. In the out-state we find an oscillatory peak in Hadamard's function as a result of the mixing between positive- and negative-energy waves. The strength of this peak is of the linear order of the Bogoliubov mixing coefficient, whereas the peak corresponding to the Schwinger mechanism is of the quadratic order. Between the in- and the out-states we observe a continuous flow of the spectral peaks together with two transient oscillatory peaks. We also discuss the medium effect at finite temperature and density. We emphasise that the entire structure of the spectral functions conveys rich information on real-time dynamics including the particle production.

  1. Effect of pulsed electric fields assisted acetylation on morphological, structural and functional characteristics of potato starch.

    Science.gov (United States)

    Hong, Jing; Chen, Rujiao; Zeng, Xin-An; Han, Zhong

    2016-02-01

    Pulsed electric fields (PEF)-assisted acetylation of potato starch with different degree of substitution (DS) was prepared and effects of PEF strength, reaction time, starch concentration on DS were studied by response surface methodology. Results showed DS was increased from 0.054 (reaction time of 15 min) to 0.130 (reaction time of 60 min) as PEF strength increased from 3 to 5 kV/cm. External morphology revealed that acetylated starch with higher DS was aggravated more bulges and asperities. Fourier-transformed infrared spectroscopy confirmed the introduction of acetyl group through a band at 1730 cm(-1). The optimum sample (DS =0 .13) had lower retrogradation (39.1%), breakdown (155 BU) and setback value (149BU), while pasting temperature (62.2 °C) was slightly higher than non-PEF-assisted samples. These results demonstrated PEF treatment can be a potential and beneficial method for acetylation and achieve higher DS with shorter reaction time.

  2. Changes of intracellular Na~+ concentration in erythrocytes caused by pulsed electrical field

    Institute of Scientific and Technical Information of China (English)

    张锦珠; 孙彤; 陈雅; 周淑华; 陈云俊; 庞素珍

    1997-01-01

    Changes of sodium ionic concentration of human erythrocytes applied to pulsed electrical field (PEF) were studied by using shift reagent and NMR spectroscopy. The results show that the concentration of intracellular Na+ increases with the increasing intensity of PEF when the erythrocytes are applied to PEF with higher intensities. The relationship between intracellular Na concentrations and the intensities of PEF does not follow linear or exponen-tial behavior. As the intensities increase, the intracellular Na+ concentrations increase even faster by an exponential curve. However under effects of PEF at lower intensities, intracellular Na+ concentration decreases. Ouabain can in-hibit the decrease of intracellular Na concentration, and the inhibition increases with the increasing concentration of ouabain, suggesting that Na , K -ATPase on cell membrane can be activated by PEF at lower intensities. Direct measurement of activities of the enzyme by using Malachite green method has confirmed this observatio

  3. The biological response of cells to nanosecond pulsed electric fields is dependent on plasma membrane cholesterol.

    Science.gov (United States)

    Cantu, Jody C; Tarango, Melissa; Beier, Hope T; Ibey, Bennett L

    2016-11-01

    Previous work from our laboratory demonstrated nanopore formation in cell membranes following exposure to nanosecond pulsed electric fields (nsPEF). We observed differences in sensitivity to nsPEF in both acute membrane injury and 24h lethality across multiple cells lines. Based on these data, we hypothesize that the biological response of cells to nsPEF is dependent on the physical properties of the plasma membrane (PM), including regional cholesterol content. Results presented in this paper show that depletion of membrane cholesterol disrupts the PM and increases the permeability of cells to small molecules, including propidium iodide and calcium occurring after fewer nsPEF. Additionally, cholesterol depletion concurrently decreases the "dose" of nsPEF required to induce lethality. In summary, the results of the current study suggest that the PM cholesterol composition is an important determinant in the cellular response to nsPEF. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Energy-efficient biomass processing with pulsed electric fields for bioeconomy and sustainable development.

    Science.gov (United States)

    Golberg, Alexander; Sack, Martin; Teissie, Justin; Pataro, Gianpiero; Pliquett, Uwe; Saulis, Gintautas; Stefan, Töpfl; Miklavcic, Damijan; Vorobiev, Eugene; Frey, Wolfgang

    2016-01-01

    Fossil resources-free sustainable development can be achieved through a transition to bioeconomy, an economy based on sustainable biomass-derived food, feed, chemicals, materials, and fuels. However, the transition to bioeconomy requires development of new energy-efficient technologies and processes to manipulate biomass feed stocks and their conversion into useful products, a collective term for which is biorefinery. One of the technological platforms that will enable various pathways of biomass conversion is based on pulsed electric fields applications (PEF). Energy efficiency of PEF treatment is achieved by specific increase of cell membrane permeability, a phenomenon known as membrane electroporation. Here, we review the opportunities that PEF and electroporation provide for the development of sustainable biorefineries. We describe the use of PEF treatment in biomass engineering, drying, deconstruction, extraction of phytochemicals, improvement of fermentations, and biogas production. These applications show the potential of PEF and consequent membrane electroporation to enable the bioeconomy and sustainable development.

  5. Effects of Pulsed Electric Field (PEF) Treatment on Enhancing Activity and Conformation of α-Amylase.

    Science.gov (United States)

    Tian, Mei-ling; Fang, Ting; Du, Mu-ying; Zhang, Fu-sheng

    2016-04-01

    To explore an efficient, safe, and speedy application of pulsed electric field (PEF) technology for enzymatic modification, effects of PEF treatment on the enzymatic activity, property and kinetic parameters of α-amylase were investigated. Conformational transitions were also studied with the aid of circular dichroism (CD) and fluorescence spectra. The maximum enzymatic activity of α-amylase was obtained under 15 kV/cm electric field intensity and 100 mL/min flow velocity PEF treatment, in which the enzymatic activity increased by 22.13 ± 1.14% compared with control. The activation effect could last for 18 h at 4 °C. PEF treatment could widen the range of optimum temperature for α-amylase, however, it barely exerted any effect on the optimum pH. On the other hand, α-amylase treated by PEF showed an increase of Vmax, t1/2 and ΔG, whereas a decrease of Km and k were observed. Furthermore, it can be observed from fluorescence and CD spectra that PEF treatment had increased the number of amino acid residues, especially that of tryptophan, on α-amylase surface with enhanced α-helices by 34.76% and decreased random coil by 12.04% on α-amylase when compared with that of untreated. These changes in structure had positive effect on enhancing α-amylase activity and property.

  6. Photobiomodulation laser and pulsed electrical field increase the viability of the musculocutaneous flap in diabetic rats.

    Science.gov (United States)

    Leite, Gabriella de Paula Marcondes Ferreira; das Neves, Lais Mara Siqueira; Silva, Carlos Alberto; Guirro, Rinaldo Roberto de Jesus; de Souza, Thamires Rodrigues; de Souza, Ana Karina; Garcia, Sérgio Britto; Guirro, Elaine Caldeira de Oliveira

    2017-04-01

    The purpose of this study is to investigate the effect of pulsed electrical field (PEF) and photobiomodulation laser (PBM) on the viability of the TRAM flap in diabetic rats. Fifty Wistar rats were divided into five homogeneous groups: Group 1-control; Group 2-diabetics; Group 3-diabetics + PEF; Group 4-diabetic + laser 660 nm, 10 J/cm(2), 0.27 J; Group 5-diabetic + laser 660 nm, 140 J/cm(2), 3.9 J. The percentage of necrotic area was evaluated using software Image J®. The peripheral circulation of the flap was evaluated by infrared thermography FLIR T450sc (FLIR® Systems-Oregon USA). The thickness of the epidermis (haematoxylin-eosin), mast cell (toluidine blue), leukocytes, vascular endothelial growth factor, fibroblast and newly formed blood vessels were evaluated. For the statistical analysis, the Kruskal-Wallis test was applied followed by Dunn and ANOVA test followed by Tukey with critical level of 5% (p electrical field increase the viability of the musculocutaneous flap in diabetic rats.

  7. Characterization of nanosecond pulse electrical field shock waves using imaging techniques

    Science.gov (United States)

    Mimun, L. Chris; Ibey, Bennett L.; Roth, Caleb C.; Barnes, Ronald A.; Sardar, Dhiraj K.; Beier, Hope T.

    2015-03-01

    Nanosecond pulsed electric fields (nsPEF) cause the formation of small pores, termed nanopores, in the membrane of cells. Current nanoporation models treat nsPEF exposure as a purely electromagnetic phenomenon, but recent publications showing pressure transients, ROS production, temperature gradients, and pH waves suggest the stimulus may be physically and chemically multifactorial causing elicitation of diverse biological conditions and stressors. Our research group's goal is to quantify the breadth and participation of these stressors generated during nsPEF exposure and determine their relative importance to the observed cellular response. In this paper, we used advanced imaging techniques to identify a possible source of nsPEF-induced acoustic shock waves. nsPEFs were delivered in an aqueous media via a pair of 125 μm tungsten electrodes separated by 100 μm, mirroring our previously published cellular exposure experiments. To visualize any pressure transients emanating from the electrodes or surrounding medium, we used the Schlieren imaging technique. Resulting images and measurements confirmed that mechanical pressure waves and electrode-based stresses are formed during nsPEF, resulting in a clearer understanding of the whole exposure dosimetry. This information will be used to better quantify the impact of nsPEF-induced acoustic shock waves on cells, and has provided further evidence of non-electrical-field induced exposures for elicitation of bioieffects.

  8. Disassembly of actin structures by nanosecond pulsed electric field is a downstream effect of cell swelling.

    Science.gov (United States)

    Pakhomov, Andrei G; Xiao, Shu; Pakhomova, Olga N; Semenov, Iurii; Kuipers, Marjorie A; Ibey, Bennett L

    2014-12-01

    Disruption of the actin cytoskeleton structures was reported as one of the characteristic effects of nanosecond-duration pulsed electric field (nsPEF) in both mammalian and plant cells. We utilized CHO cells that expressed the monomeric fluorescent protein (mApple) tagged to actin to test if nsPEF modifies the cell actin directly or as a consequence of cell membrane permeabilization. A train of four 600-ns pulses at 19.2 kV/cm (2 Hz) caused immediate cell membrane poration manifested by YO-PRO-1 dye uptake, gradual cell rounding and swelling. Concurrently, bright actin features were replaced by dimmer and uniform fluorescence of diffuse actin. To block the nsPEF-induced swelling, the bath buffer was isoosmotically supplemented with an electropore-impermeable solute (sucrose). A similar addition of a smaller, electropore-permeable solute (adonitol) served as a control. We demonstrated that sucrose efficiently blocked disassembly of actin features by nsPEF, whereas adonitol did not. Sucrose also attenuated bleaching of mApple-tagged actin in nsPEF-treated cells (as integrated over the cell volume), although did not fully prevent it. We conclude that disintegration of the actin cytoskeleton was a result of cell swelling, which, in turn, was caused by cell permeabilization by nsPEF and transmembrane diffusion of solutes which led to the osmotic imbalance.

  9. Pulsed-electric-field-assisted extraction of anthocyanins from purple-fleshed potato.

    Science.gov (United States)

    Puértolas, Eduardo; Cregenzán, Oliver; Luengo, Elisa; Alvarez, Ignacio; Raso, Javier

    2013-02-15

    The influence of pulsed electric field (PEF) treatment on the anthocyanin extraction yield (AEY) from purple-fleshed potato (PFP) at different extraction times (60-480 min) and temperatures (10-40°C) using water and ethanol (48% and 96%) as solvents has been investigated. Response surface methodology was used to determine optimal PEF treatment and optimise anthocyanin extraction. A PEF treatment of 3.4 kV/cm and 105 μs (35 pulses of 3 μs) resulted in the highest cell disintegration index (Z(p)=1) at the lowest specific energy requirements (8.92 kJ/kg). This PEF treatment increased the AEY, the effect being higher at lower extraction temperature with water as solvent. After 480 min at 40°C, the AEY obtained for the untreated sample using 96% ethanol as the solvent (63.9 mg/100 g fw) was similar to that obtained in the PEF-treated sample using water (65.8 mg/100 g fw). Therefore, PEF was possible with water, a more environmental-friendly solvent than ethanol, without decreasing the AEY from PFP.

  10. Inactivation of Ricin Toxin by Nanosecond Pulsed Electric Fields Including Evidences from Cell and Animal Toxicity

    Science.gov (United States)

    Wei, Kai; Li, Wei; Gao, Shan; Ji, Bin; Zang, Yating; Su, Bo; Wang, Kaile; Yao, Maosheng; Zhang, Jue; Wang, Jinglin

    2016-01-01

    Ricin is one of the most toxic and easily produced plant protein toxin extracted from the castor oil plant, and it has been classified as a chemical warfare agent. Here, nanosecond pulsed electric fields (nsPEFs) at 30 kV/cm (pulse durations: 10 ns, 100 ns, and 300 ns) were applied to inactivating ricin up to 4.2 μg/mL. To investigate the efficacy, cells and mice were tested against the ricin treated by the nsPEFs via direct intraperitoneal injection and inhalation exposure. Results showed that nsPEFs treatments can effectively reduce the toxicity of the ricin. Without the nsPEFs treatment, 100% of mice were killed upon the 4 μg ricin injection on the first day, however 40% of the mice survived the ricin treated by the nsPEFs. Compared to injection, inhalation exposure even with higher ricin dose required longer time to observe mice fatality. Pathological observations revealed damages to heart, lung, kidney, and stomach after the ricin exposure, more pronounced for lung and kidney including severe bleeding. Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) and circular dichroism (CD) analyses revealed that although the primary structure of ricin was not altered, its secondary structures (beta-sheet and beta-turn) underwent transition upon the nsPEFs treatment.

  11. Inactivation of Ricin Toxin by Nanosecond Pulsed Electric Fields Including Evidences from Cell and Animal Toxicity.

    Science.gov (United States)

    Wei, Kai; Li, Wei; Gao, Shan; Ji, Bin; Zang, Yating; Su, Bo; Wang, Kaile; Yao, Maosheng; Zhang, Jue; Wang, Jinglin

    2016-01-05

    Ricin is one of the most toxic and easily produced plant protein toxin extracted from the castor oil plant, and it has been classified as a chemical warfare agent. Here, nanosecond pulsed electric fields (nsPEFs) at 30 kV/cm (pulse durations: 10 ns, 100 ns, and 300 ns) were applied to inactivating ricin up to 4.2 μg/mL. To investigate the efficacy, cells and mice were tested against the ricin treated by the nsPEFs via direct intraperitoneal injection and inhalation exposure. Results showed that nsPEFs treatments can effectively reduce the toxicity of the ricin. Without the nsPEFs treatment, 100% of mice were killed upon the 4 μg ricin injection on the first day, however 40% of the mice survived the ricin treated by the nsPEFs. Compared to injection, inhalation exposure even with higher ricin dose required longer time to observe mice fatality. Pathological observations revealed damages to heart, lung, kidney, and stomach after the ricin exposure, more pronounced for lung and kidney including severe bleeding. Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) and circular dichroism (CD) analyses revealed that although the primary structure of ricin was not altered, its secondary structures (beta-sheet and beta-turn) underwent transition upon the nsPEFs treatment.

  12. Induction of Cell Death Mechanisms and Apoptosis by Nanosecond Pulsed Electric Fields (nsPEFs

    Directory of Open Access Journals (Sweden)

    Nova M. Sain

    2013-03-01

    Full Text Available Pulse power technology using nanosecond pulsed electric fields (nsPEFs offers a new stimulus to modulate cell functions or induce cell death for cancer cell ablation. New data and a literature review demonstrate fundamental and basic cellular mechanisms when nsPEFs interact with cellular targets. NsPEFs supra-electroporate cells creating large numbers of nanopores in all cell membranes. While nsPEFs have multiple cellular targets, these studies show that nsPEF-induced dissipation of ΔΨm closely parallels deterioration in cell viability. Increases in intracellular Ca2+ alone were not sufficient for cell death; however, cell death depended of the presence of Ca2+. When both events occur, cell death ensues. Further, direct evidence supports the hypothesis that pulse rise-fall times or high frequency components of nsPEFs are important for decreasing ΔΨm and cell viability. Evidence indicates in Jurkat cells that cytochrome c release from mitochondria is caspase-independent indicating an absence of extrinsic apoptosis and that cell death can be caspase-dependent and –independent. The Ca2+ dependence of nsPEF-induced dissipation of ΔΨm suggests that nanoporation of inner mitochondria membranes is less likely and effects on a Ca2+-dependent protein(s or the membrane in which it is embedded are more likely a target for nsPEF-induced cell death. The mitochondria permeability transition pore (mPTP complex is a likely candidate. Data demonstrate that nsPEFs can bypass cancer mutations that evade apoptosis through mechanisms at either the DISC or the apoptosome.

  13. Near-Field Propagation of Sub-Nanosecond Electric Pulses into Amorphous Masses

    Science.gov (United States)

    2012-02-01

    delivered at 10 Hz, the cell membrane becomes more permeable : it shows a higher leakage current compared with the cell that is not pulsed. The leakage...plication, to allow enough time for dialysis of the cytoplasm with the pipette solution. Whole-cell currents were probed by stepping the membrane...constant, were found to cause cell death and a change in membrane permeability . For the electric pulse con- dition, 200 ps, 25 kV/cm, using 1.8 million

  14. The change of electric potentials in the oral cavity after application of extremely low frequency pulsed magnetic field

    Directory of Open Access Journals (Sweden)

    Piotr Skomro

    2012-12-01

    Full Text Available Electric potentials occurring in the oral cavity deserve attention as they may cause various diseases and subjective feelings, which are very difficult to treat. The aim of this study was to evaluate the electric potentials within the oral cavity in patients with metal fillings and metal prosthetic restorations, after using a pulsed electromagnetic field. The study was carried out on 84 patients. The Viofor JPS Classic device was used in the treatment. It generates a pulsed electromagnetic field with low induction of the extremely low frequency (ELF range. Average values of electric potentials in the preliminary test were about the same in both groups; they were 148.8 mV and 145.5 mV. After another appliance of ELF fields there was found a steady decline in the average value of electric potentials in the study group. This decrease was statistically highly significant, while mean values of electric potentials in the control group were characterized by a slightly upward tendency. The obtained statistically significant reduction of electric potentials in the oral cavity of patients having metal fillings and metal prosthetic restorations, after application of the Viofor JPS Classic device, implies a huge impact of ELF pulsed electromagnetic field on inhibition of electrochemical processes, as well as on inhibition of dental alloy corrosion. 

  15. The change of electric potentials in the oral cavity after application of extremely low frequency pulsed magnetic field.

    Science.gov (United States)

    Skomro, Piotr; Lietz-Kijak, Danuta; Kijak, Edward; Bogdziewicz-Wałęsa, Olga; Opalko, Krystyna

    2012-12-11

    Electric potentials occurring in the oral cavity deserve attention as they may cause various diseases and subjective feelings, which are very difficult to treat. The aim of this study was to evaluate the electric potentials within the oral cavity in patients with metal fillings and metal prosthetic restorations, after using a pulsed electromagnetic field. The study was carried out on 84 patients. The Viofor JPS Classic device was used in the treatment. It generates a pulsed electromagnetic field with low induction of the extremely low frequency (ELF) range. Average values of electric potentials in the preliminary test were about the same in both groups; they were 148.8 mV and 145.5 mV. After another appliance of ELF fields there was found a steady decline in the average value of electric potentials in the study group. This decrease was statistically highly significant, while mean values of electric potentials in the control group were characterized by a slightly upward tendency. The obtained statistically significant reduction of electric potentials in the oral cavity of patients having metal fillings and metal prosthetic restorations, after application of the Viofor JPS Classic device, implies a huge impact of ELF pulsed electromagnetic field on inhibition of electrochemical processes, as well as on inhibition of dental alloy corrosion. 

  16. Primary pathways of intracellular Ca(2+) mobilization by nanosecond pulsed electric field.

    Science.gov (United States)

    Semenov, Iurii; Xiao, Shu; Pakhomov, Andrei G

    2013-03-01

    Permeabilization of cell membranous structures by nanosecond pulsed electric field (nsPEF) triggers transient rise of cytosolic Ca(2+) concentration ([Ca(2+)](i)), which determines multifarious downstream effects. By using fast ratiometric Ca(2+) imaging with Fura-2, we quantified the external Ca(2+) uptake, compared it with Ca(2+) release from the endoplasmic reticulum (ER), and analyzed the interplay of these processes. We utilized CHO cells which lack voltage-gated Ca(2+) channels, so that the nsPEF-induced [Ca(2+)](i) changes could be attributed primarily to electroporation. We found that a single 60-ns pulse caused fast [Ca(2+)](i) increase by Ca(2+) influx from the outside and Ca(2+) efflux from the ER, with the E-field thresholds of about 9 and 19kV/cm, respectively. Above these thresholds, the amplitude of [Ca(2+)](i) response increased linearly by 8-10nM per 1kV/cm until a critical level between 200 and 300nM of [Ca(2+)](i) was reached. If the critical level was reached, the nsPEF-induced Ca(2+) signal was amplified up to 3000nM by engaging the physiological mechanism of Ca(2+)-induced Ca(2+)-release (CICR). The amplification was prevented by depleting Ca(2+) from the ER store with 100nM thapsigargin, as well as by blocking the ER inositol-1,4,5-trisphosphate receptors (IP(3)R) with 50μM of 2-aminoethoxydiphenyl borate (2-APB). Mobilization of [Ca(2+)](i) by nsPEF mimicked native Ca(2+) signaling, but without preceding activation of plasma membrane receptors or channels. NsPEF stimulation may serve as a unique method to mobilize [Ca(2+)](i) and activate downstream cascades while bypassing the plasma membrane receptors.

  17. Effect of pulsed electric fields on the flavour profile of red-fleshed sweet cherries (Prunus avium var. Stella).

    Science.gov (United States)

    Sotelo, Kristine Ann Gualberto; Hamid, Nazimah; Oey, Indrawati; Gutierrez-Maddox, Noemi; Ma, Qianli; Leong, Sze Ying

    2015-03-23

    The aim of this research was to study the effect of pulsed electric fields (PEF) on the flavour profile of red-fleshed sweet cherries (Prunus avium variety Stella). The cherry samples were treated at a constant pulse frequency of 100 Hz, a constant pulse width of 20 μs, different electric field strengths between 0.3 and 2.5 kV/cm and specific energy ranging from 31 to 55 kJ/kg. Volatile compounds of samples were analysed using an automated headspace solid phase microextraction (HS-SPME) method coupled with gas chromatography-mass spectrometry (GC-MS). A total of 33 volatile compounds were identified with benzaldehyde, hexanal, (E)-2-hexenal, (Z)-2-hexen-1-ol, and benzyl alcohol being the predominant volatiles in different PEF-treated samples. Aldehydes namely butanal, octanal, 2-octenal, and nonanal, and (Z)-2-hexen-1-ol increased significantly 24 h after PEF treatment at electric field strengths of more than 1.0 kV/cm. Samples incubated for 24 h after PEF treatment (S3) generated higher concentrations of volatiles than samples immediately after PEF treatments (S2). Quantitative results revealed that more flavour volatiles were released and associated with S3 samples after 24 h storage and S2 samples immediately after PEF both with the highest electric field intensities. Interestingly, this study found that the PEF treatments at the applied electric field strength and energy did not result in releasing/producing undesirable flavour compounds.

  18. Fabrication Of YSZ Thin Film By Electrochemical Deposition Method And The Effect Of The Pulsed Electrical Fields For Morphology Control

    Directory of Open Access Journals (Sweden)

    Fujita T.

    2015-06-01

    Full Text Available In this study, surface morphology control ions in a precursor solution and patterning the YSZ film has been carried out during deposition of thin film from a precursor solution by applying the electrical field for deposition and the pulsed electrical field. The precursor solution was mixed them of ZrO(NO34, Y(NO33-6H2O into deionized water, and then was controlled nearly pH3 by adding NH3(aq. The thin film was deposited on the glass substrate of the minus electrode side by applying the electrical field of 3.0 V for 20 min. In addition, another pulsed voltage was applied to the electrical field along the perdicular direction to the film deposition direction. After annealing samples at 773 K for 6 h in air, the film was crystallized and obtained YSZ film. In the limited condition, the linear patterns of YSZ films due to the frequency of the applied electrical field were observed. It is expected that ions in a precursor solution are controlled by applying the pulsed voltage and the YSZ film is patterned on the substrate.

  19. Cationic peptide exposure enhances pulsed-electric-field-mediated membrane disruption.

    Directory of Open Access Journals (Sweden)

    Stephen M Kennedy

    Full Text Available The use of pulsed electric fields (PEFs to irreversibly electroporate cells is a promising approach for destroying undesirable cells. This approach may gain enhanced applicability if the intensity of the PEF required to electrically disrupt cell membranes can be reduced via exposure to a molecular deliverable. This will be particularly impactful if that reduced PEF minimally influences cells that are not exposed to the deliverable. We hypothesized that the introduction of charged molecules to the cell surfaces would create regions of enhanced transmembrane electric potential in the vicinity of each charged molecule, thereby lowering the PEF intensity required to disrupt the plasma membranes. This study will therefore examine if exposure to cationic peptides can enhance a PEF's ability to disrupt plasma membranes.We exposed leukemia cells to 40 μs PEFs in media containing varying concentrations of a cationic peptide, polyarginine. We observed the internalization of a membrane integrity indicator, propidium iodide (PI, in real time. Based on an individual cell's PI fluorescence versus time signature, we were able to determine the relative degree of membrane disruption. When using 1-2 kV/cm, exposure to >50 μg/ml of polyarginine resulted in immediate and high levels of PI uptake, indicating severe membrane disruption, whereas in the absence of peptide, cells predominantly exhibited signatures indicative of no membrane disruption. Additionally, PI entered cells through the anode-facing membrane when exposed to cationic peptide, which was theoretically expected.Exposure to cationic peptides reduced the PEF intensity required to induce rapid and irreversible membrane disruption. Critically, peptide exposure reduced the PEF intensities required to elicit irreversible membrane disruption at normally sub-electroporation intensities. We believe that these cationic peptides, when coupled with current advancements in cell targeting techniques will be

  20. Pulsed electric field inactivation of E. coli O157:H7 and surrogate bacteria in orange juice

    Science.gov (United States)

    Introduction: United States FDA juice HACCP rules mandate that orange juice (OJ) processors treat juice for a 5 log reduction of the target pathogen. Thermal pasteurization, however, reduces the sensory characteristics of OJ by removing or altering volatile compounds. Pulsed electric field (PEF) ...

  1. Effect of pulsed electric fields on the activity of neutral trehalase from beer yeast and RSM analysis.

    Science.gov (United States)

    Ye, Haiqing; Jin, Yan; Lin, Songyi; Liu, Mingyuan; Yang, Yi; Zhang, Meishuo; Zhao, Ping; Jones, Gregory

    2012-06-01

    The trehalase activity plays an important role in extraction of trehalose from beer yeast. In this study, the effect of pulsed electric field processing on neutral trehalase activity in beer yeast was investigated. In order to develop and optimize a pulsed electric field (PEF) mathematical model for activating the neutral trehalase, we have investigated three variables, including electric field intensity (10-50 kV/cm), pulse duration (2-10 μs) and liquid-solid ratio (20-50 ml/g) and subsequently optimized them by response surface methodology (RSM). The experimental data were fitted to a second-order polynomial equation and profiled into the corresponding contour plots. Optimal condition obtained by RSM is as follows: electric field intensity 42.13 kV/cm, liquid-solid ratio 30.12 ml/g and pulse duration 5.46 μs. Under these conditions, with the trehalose decreased 8.879 mg/L, the PEF treatment had great effect on activating neutral trehalase in beer yeast cells.

  2. Double-Pulse Spectra and Closed-Orbits: Photodetachment of H-in Parallel Electric and Magnetic Fields

    Institute of Scientific and Technical Information of China (English)

    DU Meng-Li

    2003-01-01

    We derive a formula for double-pulse spectra from closed-orbit theory. We then calculate the double-pulsephotodetachment spectra of H- in the presence of parallel electric and magnetic fields. We analyze the spectra in termsof closed-orbits of the system. We suggest a method for the measurement of a phase associated with each closed-orbit.

  3. Influence of vacuum impregnation and pulsed electric field on the freezing temperature and ice propagation rates of spinach leaves

    Science.gov (United States)

    Efforts are currently directed towards improving the quality of sensitive tissues of fruits and vegetables after freezing and thawing. One of the methods under investigation is the combination of vacuum impregnation (VI) with cryoprotectants and pulsed electric field (PEF) applied to the plant tiss...

  4. Upscaling from benchtop processing to industrial scale production: More factors to be considered for pulsed electric field food processing

    Science.gov (United States)

    Pulsed electric field (PEF) processing has been intensively studied with benchtop scale experiments. However, there is still limited information regarding critical factors to be considered for PEF efficacy in microbial reduction with PEF processing at a pilot or commercial scale production of juice....

  5. Selective extraction of intracellular components from the microalga Chlorella vulgaris by combined pulsed electric field-temperature treatment

    NARCIS (Netherlands)

    Postma, P.R.; Pataro, G.; Capitoli, M.; Barbosa, M.J.; Wijffels, R.H.; Eppink, M.H.M.; Olivieri, G.; Ferrari, G.

    2016-01-01

    The synergistic effect of temperature (25-65°C) and total specific energy input (0.55-1.11kWhkgDW -1) by pulsed electric field (PEF) on the release of intracellular components from the microalgae Chlorella vulgaris was studied. The combination of PEF with temperatures from 2

  6. A bioluminescence ATP assay for estimating surface hydrophobicity and membrane damage of Escherichia coli cells treated with pulsed electric fields

    Science.gov (United States)

    Pulse Electric Field (PEF) treatments, a non-thermal process have been reported to injure and inactivate bacteria in liquid foods. However, the effect of this treatment on bacterial cell surface charge and hydrophobicity has not been investigated. Apple juice (AJ, pH 3.8) purchased from a wholesale ...

  7. Selective extraction of intracellular components from the microalga Chlorella vulgaris by combined pulsed electric field-temperature treatment

    NARCIS (Netherlands)

    Postma, P.R.; Pataro, G.; Capitoli, M.; Barbosa, M.J.; Wijffels, R.H.; Eppink, M.H.M.; Olivieri, G.; Ferrari, G.

    2016-01-01

    The synergistic effect of temperature (25-65°C) and total specific energy input (0.55-1.11kWhkgDW -1) by pulsed electric field (PEF) on the release of intracellular components from the microalgae Chlorella vulgaris was studied. The combination of PEF with temperatures from

  8. X-ray emission from a nanosecond-pulse discharge in an inhomogeneous electric field at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Cheng; Shao Tao; Ren Chengyan; Zhang Dongdong [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); Tarasenko, Victor; Kostyrya, Igor D. [Institute of High Current Electronics, Russian Academy of Science, Tomsk 634055 (Russian Federation); Ma Hao [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Yan Ping [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China)

    2012-12-15

    This paper describes experimental studies of the dependence of the X-ray intensity on the anode material in nanosecond high-voltage discharges. The discharges were generated by two nanosecond-pulse generators in atmospheric air with a highly inhomogeneous electric field by a tube-plate gap. The output pulse of the first generator (repetitive pulse generator) has a rise time of about 15 ns and a full width at half maximum of 30-40 ns. The output of the second generator (single pulse generator) has a rise time of about 0.3 ns and a full width at half maximum of 1 ns. The electrical characteristics and the X-ray emission of nanosecond-pulse discharge in atmospheric air are studied by the measurement of voltage-current waveforms, discharge images, X-ray count and dose. Our experimental results showed that the anode material rarely affects electrical characteristics, but it can significantly affect the X-ray density. Comparing the density of X-rays, it was shown that the highest x-rays density occurred in the diffuse discharge in repetitive pulse mode, then the spark discharge with a small air gap, and then the corona discharge with a large air gap, in which the X-ray density was the lowest. Therefore, it could be confirmed that the bremsstrahlung at the anode contributes to the X-ray emission from nanosecond-pulse discharges.

  9. Growth and apoptosis of HeLa cells induced by intense picosecond pulsed electric field

    Directory of Open Access Journals (Sweden)

    Yuan-yuan HUA

    2011-07-01

    Full Text Available Objective To investigate the growth and apoptosis of HeLa cells induced by intense picosecond pulsed electric field(PEF in vitro.Methods HeLa cells cultured in vitro were divided into experimental group and control group(with or without intense picosecond PEF.With constant pulse width,frequency and voltage,the cells in experimental group were divided into 6 sub-groups according to the number of pulse(100,200,500,1000,1500,2000,the growth inhibition of HeLa cells by PEF and the dose-effect relationship were analyzed by MTT.Caspase 3 protein activity was detected in the cells in 500,1000 and 2000 sub-groups.Mitochondrial transmembrane potential was detected by rhodamine 123 staining with the cells in 2000 sub-groups.Results MTT assay demonstrated that intense picosecond PEF significantly inhibited the proliferation of HeLa cells in dose-dependent manner.The survival rates of cells declined along with the increase in pulse number,and were 96.23%±0.76%,94.11%±2.42%,90.31%±1.77%,64.59%±1.59%,32.95%±0.73%,23.85%±2.38% and 100%,respectively,in 100,200,500,1000,1500,2000 sub-groups and control group(P < 0.01.The Caspase 3 protein activity was significantly enhanced by intense picosecond PEF,and the absorbancy indexes(A were 0.174±0.012,0.232±0.017,0.365±0.016 and 0.122±0.011,respectively,in 500,1000,2000 sub-groups and control group(P < 0.05.The mitochondrial transmembrane potential of HeLa cells was significantly inhibited by intense picosecond PEF,and the fluorescence intensity in 2000 sub-group(76.66±13.38 was much lower than that in control group(155.81±2.33,P < 0.05.Conclusion Intense picosecond PEF may significantly inhibit the growth of HeLa cells,and induce cell apoptosis via mitochondrial pathway.

  10. A bacterial spore model of pulsed electric fields on spore morphology change revealed by simulation and SEM.

    Science.gov (United States)

    Qiu, Xing; Lee, Yin Tung; Yung, Pun To

    2014-01-01

    A two-layered spore model was proposed to analyze morphological change of bacterial spores subjected under pulsed electric fields. The outer layer, i.e. spore coat, was defined by Mooney-Rivlin hyper-elastic material model. The inner layer, i.e. peptidoglycan and spore core, was modeled by applying additional adhesion forces. The effect of pulsed electric fields on surface displacement was simulated in COMSOL Multiphysics and verified by SEM. The electro-mechanical theory, considering spore coat as a capacitor, was used to explain concavity; and the thin viscoelastic film theory, considering membrane bilayer as fluctuating surfaces, was used to explain leakage forming. Mutual interaction of external electric fields, charged spores, adhesion forces and ions movement were all predicted to contribute to concavity and leakage.

  11. Defining treatment conditions for pulsed electric field pasteurization of apple juice.

    Science.gov (United States)

    Saldaña, G; Puértolas, E; Monfort, S; Raso, J; Alvarez, I

    2011-11-15

    The influence of temperature and the presence of N(α)-lauroyl ethylester (ethyl lauroyl arginate, LAE) on the inactivation caused by continuous pulsed electric field treatments (PEF) in Escherichia coli O157:H7 suspended in apple juice have been investigated to define treatment conditions applicable at industrial scale that promote an equivalent safety level when compared with thermal processing. In the range of experimental conditions investigated (outlet temperature: 20-40 °C, electric field strength: 20-30 kV, treatment time: 5-125 μs) at outlet temperatures equal or lower than 55±1 °C, the inactivation of E. coli O157:H7 treated in apple juice ranged from 0.4 to 3.6 Log₁₀ cycles reduction and treated in apple juice supplemented with LAE (50 ppm) ranged from 0.9 to 6.7 Log₁₀ cycles reduction. An empirical mathematical model was developed to estimate the treatment time and total specific energy input to obtain 5 Log₁₀ cycles reduction in the population of E. coli O157:H7 suspended in apple juice supplemented with 50 ppm of LAE at different electric field strengths and inlet temperatures. Treatment conditions established for E. coli O157:H7 were validated with other PEF resistant Gram-positive (Listeria monocytogenes, and Staphylococcus aureus) and Gram-negative (Salmonella enterica serovar Typhimurium) strains. When the treatment was applied to the apple juice, a treatment of 25 kV/cm for 63 μs corresponding with an outlet temperature of 65 °C and input energy of 125 kJ/kg was required to achieve more than 5 Log₁₀ cycles in the four strains investigated. The addition of LAE reduced the treatment time required to obtain an equivalent inactivation (>5 Log₁₀ cycles) in the four microorganisms to 38.4 μs, the outlet temperature to 55 °C, and the input energy to 83.2 kJ/kg.

  12. Metal release in a stainless steel pulsed electric field (PEF) system Part II. The treatment of orange juice; related to legislation and treatment chamber lifetime

    NARCIS (Netherlands)

    Roodenburg, B.; Morren, J.; Berg, H.E.; Haan, S.W.H.de

    2005-01-01

    In the last decennia, there is an increasing interest in pulsed electric field (PEF) treatment. The product is often treated in a continuous flow treatment chamber with stainless steel electrodes and exposed to short pulsed electric fields, typically 2-4 kV mm-1 during 1-10 μs. Due to direct contact

  13. Metal release in a stainless steel pulsed electric field (PEF) system Part II. The treatment of orange juice; related to legislation and treatment chamber lifetime

    NARCIS (Netherlands)

    Roodenburg, B.; Morren, J.; Berg, H.E.; Haan, S.W.H.de

    2005-01-01

    In the last decennia, there is an increasing interest in pulsed electric field (PEF) treatment. The product is often treated in a continuous flow treatment chamber with stainless steel electrodes and exposed to short pulsed electric fields, typically 2-4 kV mm-1 during 1-10 μs. Due to direct contact

  14. Calcium-independent disruption of microtubule dynamics by nanosecond pulsed electric fields in U87 human glioblastoma cells

    Science.gov (United States)

    Carr, Lynn; Bardet, Sylvia M.; Burke, Ryan C.; Arnaud-Cormos, Delia; Leveque, Philippe; O’Connor, Rodney P.

    2017-01-01

    High powered, nanosecond duration, pulsed electric fields (nsPEF) cause cell death by a mechanism that is not fully understood and have been proposed as a targeted cancer therapy. Numerous chemotherapeutics work by disrupting microtubules. As microtubules are affected by electrical fields, this study looks at the possibility of disrupting them electrically with nsPEF. Human glioblastoma cells (U87-MG) treated with 100, 10 ns, 44 kV/cm pulses at a frequency of 10 Hz showed a breakdown of their interphase microtubule network that was accompanied by a reduction in the number of growing microtubules. This effect is temporally linked to loss of mitochondrial membrane potential and independent of cellular swelling and calcium influx, two factors that disrupt microtubule growth dynamics. Super-resolution microscopy revealed microtubule buckling and breaking as a result of nsPEF application, suggesting that nsPEF may act directly on microtubules. PMID:28117459

  15. Calcium-independent disruption of microtubule dynamics by nanosecond pulsed electric fields in U87 human glioblastoma cells.

    Science.gov (United States)

    Carr, Lynn; Bardet, Sylvia M; Burke, Ryan C; Arnaud-Cormos, Delia; Leveque, Philippe; O'Connor, Rodney P

    2017-01-24

    High powered, nanosecond duration, pulsed electric fields (nsPEF) cause cell death by a mechanism that is not fully understood and have been proposed as a targeted cancer therapy. Numerous chemotherapeutics work by disrupting microtubules. As microtubules are affected by electrical fields, this study looks at the possibility of disrupting them electrically with nsPEF. Human glioblastoma cells (U87-MG) treated with 100, 10 ns, 44 kV/cm pulses at a frequency of 10 Hz showed a breakdown of their interphase microtubule network that was accompanied by a reduction in the number of growing microtubules. This effect is temporally linked to loss of mitochondrial membrane potential and independent of cellular swelling and calcium influx, two factors that disrupt microtubule growth dynamics. Super-resolution microscopy revealed microtubule buckling and breaking as a result of nsPEF application, suggesting that nsPEF may act directly on microtubules.

  16. Effect of Pulsed Electric Field on Membrane Lipids and Oxidative Injury of Salmonella typhimurium.

    Science.gov (United States)

    Yun, Ou; Zeng, Xin-An; Brennan, Charles S; Han, Zhong

    2016-08-22

    Salmonella typhimurium cells were subjected to pulsed electric field (PEF) treatment at 25 kV/cm for 0-4 ms to investigate the effect of PEF on the cytoplasmic membrane lipids and oxidative injury of cells. Results indicated that PEF treatment induced a decrease of membrane fluidity of Salmonella typhimurium (S. typhimuriumi), possibly due to the alterations of fatty acid biosynthesis-associated gene expressions (down-regulation of cfa and fabA gene expressions and the up-regulation of fabD gene expression), which, in turn, modified the composition of membrane lipid (decrease in the content ratio of unsaturated fatty acids to saturated fatty acids). In addition, oxidative injury induced by PEF treatment was associated with an increase in the content of malondialdehyde. The up-regulation of cytochrome bo oxidase gene expressions (cyoA, cyoB, and cyoC) indicated that membrane damage was induced by PEF treatment, which was related to the repairing mechanism of alleviating the oxidative injury caused by PEF treatment. Based on these results, we achieved better understanding of microbial injury induced by PEF, suggesting that micro-organisms tend to decrease membrane fluidity in response to PEF treatment and, thus, a greater membrane fluidity might improve the efficiency of PEF treatment to inactivate micro-organisms.

  17. Decontamination of collagen biomatrices with combined pulsed electric field and nisin treatment.

    Science.gov (United States)

    Griffiths, Sarah; Maclean, Michelle; Macgregor, Scott J; Anderson, John G; Helen Grant, M

    2011-02-01

    Pulsed electric field (PEF) treatment has been proposed as a decontamination method for labile matrices used in tissue engineering applications. Through the application of PEF, a non-thermal treatment that causes bacterial inactivation through the irreversible rupture of microbial cell membranes, inactivation is achieved without loss of scaffold structure and function. However, some microorganisms are less susceptible to PEF treatment. This study shows that treatment with PEF and nisin, a food preservative bacteriocin, has a synergistic effect on the inactivation of Staphylococcus epidermidis in collagen gels. Almost complete inactivation of a 10(3) -10(4) CFU/mL S. epidermidis population was achieved when treated with a combination of PEF and 500 IU/mL nisin, with results demonstrating a 3.4 log(10) reduction, compared with 0.66 log(10) reduction with PEF alone. Nisin, at concentrations up to 3000 IU/mL, had no discernable toxicity to mammalian 3T3 cells when added to the culture medium or incorporated into the collagen gels. This combined decontamination method, involving PEF plus nisin, may provide a non-destructive process for inactivation of PEF-resistant bacteria in labile tissue engineering scaffolds.

  18. Pulsed electric field treatment enhanced stilbene content in Graciano, Tempranillo and Grenache grape varieties.

    Science.gov (United States)

    López-Alfaro, Isabel; González-Arenzana, Lucía; López, Noelia; Santamaría, Pilar; López, Rosa; Garde-Cerdán, Teresa

    2013-12-15

    The purpose of this paper was to study the effect of pulsed electric fields (PEF) on the stilbene content of three grape varieties. For this purpose, four different PEF treatments were applied using a continuous system over three varieties, Graciano, Tempranillo and Grenache, destemmed and crushed. In addition, the influence of PEF on their physicochemical composition was studied. PEF treatments did not affect the pH or total acidity of Graciano, however, musts from Tempranillo and Grenache had higher pH values and lower total acidity. In the three varieties, all treatments resulted in an increase of potassium content, deeper colour intensity and total polyphenol index and lower tonality, more pronounced in the treatments with higher time and energy. The stilbene content of the must significantly increased with respect to the control. This increase depended on the variety and the treatment applied. Tempranillo increased up 200% the total stilbene concentration, Grenache 60% and Graciano 50%. For the three varieties, the treatment with the highest time and energy was the most effective on the total stilbene extraction. These results indicate that PEF could be a suitable technology for obtaining musts with deeper colour and higher phenolic content, including resveratrol and piceid.

  19. Effect of Pulsed Electric Field on Membrane Lipids and Oxidative Injury of Salmonella typhimurium

    Directory of Open Access Journals (Sweden)

    Ou Yun

    2016-08-01

    Full Text Available Salmonella typhimurium cells were subjected to pulsed electric field (PEF treatment at 25 kV/cm for 0–4 ms to investigate the effect of PEF on the cytoplasmic membrane lipids and oxidative injury of cells. Results indicated that PEF treatment induced a decrease of membrane fluidity of Salmonella typhimurium (S. typhimuriumi, possibly due to the alterations of fatty acid biosynthesis-associated gene expressions (down-regulation of cfa and fabA gene expressions and the up-regulation of fabD gene expression, which, in turn, modified the composition of membrane lipid (decrease in the content ratio of unsaturated fatty acids to saturated fatty acids. In addition, oxidative injury induced by PEF treatment was associated with an increase in the content of malondialdehyde. The up-regulation of cytochrome bo oxidase gene expressions (cyoA, cyoB, and cyoC indicated that membrane damage was induced by PEF treatment, which was related to the repairing mechanism of alleviating the oxidative injury caused by PEF treatment. Based on these results, we achieved better understanding of microbial injury induced by PEF, suggesting that micro-organisms tend to decrease membrane fluidity in response to PEF treatment and, thus, a greater membrane fluidity might improve the efficiency of PEF treatment to inactivate micro-organisms.

  20. Nanosecond pulsed electric field induced cytoskeleton, nuclear membrane and telomere damage adversely impact cell survival.

    Science.gov (United States)

    Stacey, M; Fox, P; Buescher, S; Kolb, J

    2011-10-01

    We investigated the effects of nanosecond pulsed electric fields (nsPEF) on three human cell lines and demonstrated cell shrinkage, breakdown of the cytoskeleton, nuclear membrane and chromosomal telomere damage. There was a differential response between cell types coinciding with cell survival. Jurkat cells showed cytoskeleton, nuclear membrane and telomere damage that severely impacted cell survival compared to two adherent cell lines. Interestingly, disruption of the actin cytoskeleton in adherent cells prior to nsPEF exposure significantly reduced cell survival. We conclude that nsPEF applications are able to induce damage to the cytoskeleton and nuclear membrane. Telomere sequences, regions that tether and stabilize DNA to the nuclear membrane, are severely compromised as measured by a pan-telomere probe. Internal pore formation following nsPEF applications has been described as a factor in induced cell death. Here we suggest that nsPEF induced physical changes to the cell in addition to pore formation need to be considered as an alternative method of cell death. We suggest nsPEF electrochemical induced depolymerization of actin filaments may account for cytoskeleton and nuclear membrane anomalies leading to sensitization.

  1. The Effects of Theine Content of Pu’er Tea in Hige Pulsed Electric Field

    Directory of Open Access Journals (Sweden)

    Zhao Yan

    2014-10-01

    Full Text Available This essay is based on the experiment of comparing the theine content of sample Yunnan Mengku large-leaf-variety Pu’er tea before and after the treatment of Hige Pulsed Electric Field (HPEF. During this experiment, the differences of content of theine are measured based on different processing techniques of tea (fermented and not fermented, different producing years and different HPEF. The results of the experiments are as follows. First, the difference of the content of theine is notable between fermented and not fermented tea produced in the same year and the theine content of non-fermented tea is larger than that in fermented tea. Second, the content of theine is decreasing with the increase of the length of storage. Third, the content of theine is reduced drastically in samples treated by different conditions of HPEF. The decrease of the content of theine and the major index of quality of Pu’er tea in samples treated by HPEF is consistent with that of natural-aging Pu’er tea. The results of this experiment provide theoretical foundation to further research of aging tea by HPEF.

  2. Characteristics and Antitumor Activity of Morchella esculenta Polysaccharide Extracted by Pulsed Electric Field

    Directory of Open Access Journals (Sweden)

    Chao Liu

    2016-06-01

    Full Text Available Polysaccharides from Morchella esculenta have been proven to be functional and helpful for humans. The purpose of this study was to investigate the chemical structure and anti-proliferating and antitumor activities of a Morchella esculenta polysaccharide (MEP extracted by pulsed electric field (PEF in submerged fermentation. The endo-polysaccharide was separated and purified by column chromatography and Gel permeation chromatography, and analyzed by gas chromatography. The MEP with an average molecular weight of 81,835 Da consisted of xylose, glucose, mannose, rhamnose and galactose at the ratio of 5.4:5.0:6.5:7.8:72.3. Structure of MEP was further analyzed by Fourier-transform infrared spectroscopy and 1H and 13C liquid-state nuclear magnetic resonance spectroscopy. Apoptosis tests proved that MEP could inhibit the proliferation and growth of human colon cancer HT-29 cells in a time- and dose-dependent manner within 48 h. This study provides more information on chemical structure of anti-proliferating polysaccharides isolated from Morchella esculenta.

  3. Characteristics and Antitumor Activity of Morchella esculenta Polysaccharide Extracted by Pulsed Electric Field.

    Science.gov (United States)

    Liu, Chao; Sun, Yonghai; Mao, Qian; Guo, Xiaolei; Li, Peng; Liu, Yang; Xu, Na

    2016-06-22

    Polysaccharides from Morchella esculenta have been proven to be functional and helpful for humans. The purpose of this study was to investigate the chemical structure and anti-proliferating and antitumor activities of a Morchella esculenta polysaccharide (MEP) extracted by pulsed electric field (PEF) in submerged fermentation. The endo-polysaccharide was separated and purified by column chromatography and Gel permeation chromatography, and analyzed by gas chromatography. The MEP with an average molecular weight of 81,835 Da consisted of xylose, glucose, mannose, rhamnose and galactose at the ratio of 5.4:5.0:6.5:7.8:72.3. Structure of MEP was further analyzed by Fourier-transform infrared spectroscopy and ¹H and (13)C liquid-state nuclear magnetic resonance spectroscopy. Apoptosis tests proved that MEP could inhibit the proliferation and growth of human colon cancer HT-29 cells in a time- and dose-dependent manner within 48 h. This study provides more information on chemical structure of anti-proliferating polysaccharides isolated from Morchella esculenta.

  4. The influence of pulsed electric field on hematological parameters in rat.

    Science.gov (United States)

    Coskun, Ozlem; Comlekci, Selcuk

    2013-10-01

    The aim of the present study is to investigate whether or not pulsed electric field (PEF) affects some hematological parameters in rats. Sixteen healthy male Wistar rats weighting 150-200 g were used and were randomly divided into two groups. Exposure group (n = 8) was exposed to a PEF (10 kV m⁻¹ for 1 h d⁻¹) for 10 consecutive days. The control group rats (n = 8) were not exposed to PEF. The following hematological parameters were measured in both the groups: white blood cells (WBCs), red blood cells (RBCs), hemoglobin (Hb), hematocrit (Ht) and platelets (PLTs). Some of the hematological parameters under investigation were similar in both the groups. Exposure group, exposed for 1 h d⁻¹ during 10 consecutive days, induced a significant increase in the rates of WBC (p < 0.05), RBC (p < 0.05), Hb (p < 0.05), Ht (p < 0.05) and PLTs (p < 0.05) in blood when compared with control. These results suggest that PEFs affect the hematological parameters in rat. Results of the parameters are statistically significant.

  5. Release of Mannoproteins during Saccharomyces cerevisiae Autolysis Induced by Pulsed Electric Field.

    Science.gov (United States)

    Martínez, Juan M; Cebrián, Guillermo; Álvarez, Ignacio; Raso, Javier

    2016-01-01

    The potential of the application of pulsed electric fields (PEF) to induce accelerate autolysis of a commercial strain of Saccharomyces cerevisiae for winemaking use was evaluated. The influence of PEF treatments of different intensity (5-25 kV/cm for 30-240 μs) on cell viability, cytoplasmic membrane permeabilization and release of mannoproteins and compounds absorbing at 260 and 280 nm has been investigated. After 8 days of incubation at 25°C the Abs600 of the suspension containing the control cells was kept constant while the Abs600 of the suspension containing the cells treated by PEF decreased. The measurement of the absorbance at 260 and 280 nm revealed no release of UV absorbing material from untreated cells after 8 days of incubation but the amount of UV absorbing material released drastically increased in the samples that contained cells treated by PEF after the same storage period. After 18 days of storage the amount of mannoproteins released from the untreated cell was negligible. Conversely, mannoprotein concentration increased linearly for the samples containing cells of S. cerevisiae treated by PEF. After 18 days of incubation the concentration of mannoproteins in the supernatant increased 4.2 times for the samples containing cells treated by PEF at 15 and 25 kV/cm for 45 and 150 μs. Results obtained in this study indicates that PEF could be used in winemaking to accelerate the sur lie aging or to obtain mannoproteins from yeast cultures.

  6. Activation of autophagy in response to nanosecond pulsed electric field exposure.

    Science.gov (United States)

    Ullery, Jody C; Tarango, Melissa; Roth, Caleb C; Ibey, Bennett L

    2015-03-06

    Previous work demonstrated significant changes in cellular membranes following exposure of cells to nanosecond pulsed electric fields (nsPEF), including nanoporation and increases in intracellular calcium concentration. While it is known that nsPEF exposure can cause cell death, how cells repair and survive nsPEF-induced cellular damage is not well understood. In this paper, we investigated whether autophagy is stimulated following nsPEF exposure to repair damaged membranes, proteins, and/or organelles in a pro-survival response. We hypothesized that autophagy is activated to repair nsPEF-induced plasma membrane damage and overwhelming this compensatory mechanism results in cell death. Activation of autophagy and subsequent cell death pathways were assessed measuring toxicity, gene and protein expression of autophagy markers, and by monitoring autophagosome formation and maturation using fluorescent microscopy. Results show that autophagy is activated at subtoxic nsPEF doses, as a compensatory mechanism to repair membrane damage. However, prolonged exposure results in increased cell death and a concomitant decrease in autophagic markers. These results suggest that cells take an active role in membrane repair, through autophagy, following exposure to nsPEF.

  7. Release of Mannoproteins during Saccharomyces cerevisiae Autolysis Induced by Pulsed Electric Field

    Science.gov (United States)

    Martínez, Juan M.; Cebrián, Guillermo; Álvarez, Ignacio; Raso, Javier

    2016-01-01

    The potential of the application of pulsed electric fields (PEF) to induce accelerate autolysis of a commercial strain of Saccharomyces cerevisiae for winemaking use was evaluated. The influence of PEF treatments of different intensity (5–25 kV/cm for 30–240 μs) on cell viability, cytoplasmic membrane permeabilization and release of mannoproteins and compounds absorbing at 260 and 280 nm has been investigated. After 8 days of incubation at 25°C the Abs600 of the suspension containing the control cells was kept constant while the Abs600 of the suspension containing the cells treated by PEF decreased. The measurement of the absorbance at 260 and 280 nm revealed no release of UV absorbing material from untreated cells after 8 days of incubation but the amount of UV absorbing material released drastically increased in the samples that contained cells treated by PEF after the same storage period. After 18 days of storage the amount of mannoproteins released from the untreated cell was negligible. Conversely, mannoprotein concentration increased linearly for the samples containing cells of S. cerevisiae treated by PEF. After 18 days of incubation the concentration of mannoproteins in the supernatant increased 4.2 times for the samples containing cells treated by PEF at 15 and 25 kV/cm for 45 and 150 μs. Results obtained in this study indicates that PEF could be used in winemaking to accelerate the sur lie aging or to obtain mannoproteins from yeast cultures. PMID:27672386

  8. Inactivation of Escherichia coli phage by pulsed electric field treatment and analysis of inactivation mechanism

    Science.gov (United States)

    Tanino, Takanori; Yoshida, Tomoki; Sakai, Kazuki; Ohshima, Takayuki

    2013-03-01

    Inactivation of bacteriophage by pulsed electric field (PEF) treatment, one of the effective procedures for bacteria nonthermal inactivation, was studied. Model phage particles Escherichia coli bacteriophages M13mp18 and λ phage, were successfully inactivated by PEF treatment. The survival ratios of both bacteriophages decreased depending on the PEF treatment time when applied peak voltage was 5 or 7 kV, and the survival ratios after 12 min PEF treatment were 10-4 - 10-5. Electrophoresis analyses of biological molecules of inactivated λ phage detected no degradation of total protein and genomic DNA. These results suggested that the factor of phage inactivation by PEF treatment was not based on the degradation of protein or DNA, but on the destruction of phage particle structure. Sensitivity of E. coli phage to PEF treatment was compared with that of E. coli cell. Phage and MV1184 cell were treated with same condition PEF at 5 kV, respectively. After 12 min treatment, the survival ration of λ phage and MV1184 were 4.0 × 10-5 and 1.7 × 10-3, respectively. The survival ratio of phage was lower than that of MV1184. E. coli cell is more tolerant to inactivation with PEF treatment than coli phage.

  9. Effect of Pulsed Electric Field on Membrane Lipids and Oxidative Injury of Salmonella typhimurium

    Science.gov (United States)

    Yun, Ou; Zeng, Xin-An; Brennan, Charles S.; Han, Zhong

    2016-01-01

    Salmonella typhimurium cells were subjected to pulsed electric field (PEF) treatment at 25 kV/cm for 0–4 ms to investigate the effect of PEF on the cytoplasmic membrane lipids and oxidative injury of cells. Results indicated that PEF treatment induced a decrease of membrane fluidity of Salmonella typhimurium (S. typhimuriumi), possibly due to the alterations of fatty acid biosynthesis-associated gene expressions (down-regulation of cfa and fabA gene expressions and the up-regulation of fabD gene expression), which, in turn, modified the composition of membrane lipid (decrease in the content ratio of unsaturated fatty acids to saturated fatty acids). In addition, oxidative injury induced by PEF treatment was associated with an increase in the content of malondialdehyde. The up-regulation of cytochrome bo oxidase gene expressions (cyoA, cyoB, and cyoC) indicated that membrane damage was induced by PEF treatment, which was related to the repairing mechanism of alleviating the oxidative injury caused by PEF treatment. Based on these results, we achieved better understanding of microbial injury induced by PEF, suggesting that micro-organisms tend to decrease membrane fluidity in response to PEF treatment and, thus, a greater membrane fluidity might improve the efficiency of PEF treatment to inactivate micro-organisms. PMID:27556460

  10. Characteristics and Antitumor Activity of Morchella esculenta Polysaccharide Extracted by Pulsed Electric Field

    Science.gov (United States)

    Liu, Chao; Sun, Yonghai; Mao, Qian; Guo, Xiaolei; Li, Peng; Liu, Yang; Xu, Na

    2016-01-01

    Polysaccharides from Morchella esculenta have been proven to be functional and helpful for humans. The purpose of this study was to investigate the chemical structure and anti-proliferating and antitumor activities of a Morchella esculenta polysaccharide (MEP) extracted by pulsed electric field (PEF) in submerged fermentation. The endo-polysaccharide was separated and purified by column chromatography and Gel permeation chromatography, and analyzed by gas chromatography. The MEP with an average molecular weight of 81,835 Da consisted of xylose, glucose, mannose, rhamnose and galactose at the ratio of 5.4:5.0:6.5:7.8:72.3. Structure of MEP was further analyzed by Fourier-transform infrared spectroscopy and 1H and 13C liquid-state nuclear magnetic resonance spectroscopy. Apoptosis tests proved that MEP could inhibit the proliferation and growth of human colon cancer HT-29 cells in a time- and dose-dependent manner within 48 h. This study provides more information on chemical structure of anti-proliferating polysaccharides isolated from Morchella esculenta. PMID:27338370

  11. Extraction of Bioactive Compounds from Two Grape Varieties Using Pulsed Electric Field

    Directory of Open Access Journals (Sweden)

    Simona Ioana VICAS

    2016-11-01

    Full Text Available In this paper, our objective was to investigate extraction efficiency of polyphenols with antioxidant capacity from two varieties of grapes (white-Muscat Ottonel (MO and red-Pinot Noir (PN using pulsed electric field (PEF. Grapes were harvested in the Crisana Santimreu vineyard in 2015. The grapes were declustered and crushed, and have been divided into three parts. A part was treated in PEF, the second one was homogenized, and then was treated in PEF and the last part remained untreated, representing the control samples. The bioactive compounds, like total polyphenol content and total flavonoid content, were determined by the spectrophotometric method. The antioxidant capacity of the samples was determined by three methods (DPPH, FRAPand TEAC. Our results show that the application of PEF to the crushed grapes increases the total polyphenol content 2.28 and 3.15 times and the total flavonoid content 7.17 and 5.29 times for MO and PN, respectively. Also, the antioxidant capacity was significantly increased when it was compared with the control sample. When the treatment in PEF was applied on homogenized grapes both bioactive compounds and antioxidant capacity were significantly increased compared to the samples treated in PEF for crushed grapes. In the present research work, we demonstrated that the application of PEF to two different grape varieties significantly increased the level of total polyphenols and flavonoids and also the antioxidant capacity. The application of PEF to homogenized grapes was more efficient.

  12. Electrochemical reaction and oxidation of lecithin under pulsed electric fields (PEF) processing.

    Science.gov (United States)

    Zhao, Wei; Yang, Ruijin; Liang, Qi; Zhang, Wenbin; Hua, Xiao; Tang, Yali

    2012-12-12

    Pulsed electric fields (PEF) processing is a promising nonthermal food preservation technology, which is ongoing from laboratory and pilot plant scale levels to the industrial level. Currently, greater attention has been paid to side effects occurring during PEF treatment and the influences on food qualities and food components. The present study investigated the electrochemical reaction and oxidation of lecithin under PEF processing. Results showed that electrochemical reaction of NaCl solutions at different pH values occurred during PEF processing. Active chlorine, reactive oxygen, and free radicals were detected, which were related to the PEF parameters and pH values of the solution. Lecithin extracted from yolk was further selected to investigate the oxidation of food lipids under PEF processing, confirming the occurrence of oxidation of lecithin under PEF treatment. The oxidative agents induced by PEF might be responsible for the oxidation of extracted yolk lecithin. Moreover, this study found that vitamin C as a natural antioxidant could effectively quench free radicals and inhibit the oxidation of lipid in NaCl and lecithin solutions as model systems under PEF processing, representing a way to minimize the impact of PEF treatment on food qualities.

  13. Direct activation of the Mauthner cell by electric field pulses drives ultrarapid escape responses

    Science.gov (United States)

    Tabor, Kathryn M.; Bergeron, Sadie A.; Horstick, Eric J.; Jordan, Diana C.; Aho, Vilma; Porkka-Heiskanen, Tarja; Haspel, Gal

    2014-01-01

    Rapid escape swims in fish are initiated by the Mauthner cells, giant reticulospinal neurons with unique specializations for swift responses. The Mauthner cells directly activate motoneurons and facilitate predator detection by integrating acoustic, mechanosensory, and visual stimuli. In addition, larval fish show well-coordinated escape responses when exposed to electric field pulses (EFPs). Sensitization of the Mauthner cell by genetic overexpression of the voltage-gated sodium channel SCN5 increased EFP responsiveness, whereas Mauthner ablation with an engineered variant of nitroreductase with increased activity (epNTR) eliminated the response. The reaction time to EFPs is extremely short, with many responses initiated within 2 ms of the EFP. Large neurons, such as Mauthner cells, show heightened sensitivity to extracellular voltage gradients. We therefore tested whether the rapid response to EFPs was due to direct activation of the Mauthner cells, bypassing delays imposed by stimulus detection and transmission by sensory cells. Consistent with this, calcium imaging indicated that EFPs robustly activated the Mauthner cell but only rarely fired other reticulospinal neurons. Further supporting this idea, pharmacological blockade of synaptic transmission in zebrafish did not affect Mauthner cell activity in response to EFPs. Moreover, Mauthner cells transgenically expressing a tetrodotoxin (TTX)-resistant voltage-gated sodium channel retained responses to EFPs despite TTX suppression of action potentials in the rest of the brain. We propose that EFPs directly activate Mauthner cells because of their large size, thereby driving ultrarapid escape responses in fish. PMID:24848468

  14. Effects of Pulsed Electric Fields (PEF on Vitamin C and Its Antioxidant Properties

    Directory of Open Access Journals (Sweden)

    Zhi-Hong Zhang

    2015-10-01

    Full Text Available In this study, pulsed electric fields (PEF treatments and their effects on the structure of vitamin C (VIT-C were estimated by fluorescence and Fourier transform infrared (FT-IR spectroscopy, the relative content of VIT-C was measured by HPLC and the antioxidant properties of treated VIT-C by DPPH radical scavenging as well as reducing power tests. The fluorescence intensity of treated VIT-C increased slightly compared to the untreated VIT-C. Moreover, the effect of PEF on the structure of VIT-C was observed using the FT-IR spectra. These phenomena indicated that the PEF affected the conformation of VIT-C, which promoted the VIT-C isomer transformed enol-form into keto-form. In addition, the PEF treatments did not suffer the damage to VIT-C and could slow down the oxidation process in involving of experimental conditions by HPLC. The antioxidant properties of the treated VIT-C were enhanced, which was proved by radical scavenging and also the reducing power tests.

  15. Coherent time evolution of highly excited Rydberg states in pulsed electric field Opening a stringent way to selectively field-ionize the highly excited states

    CERN Document Server

    Tada, M; Ogawa, I; Funahashi, H; Yamamoto, K; Matsuki, S

    2000-01-01

    Coherent time evolution of highly excited Rydberg states in Rb (98 < n < 150) under pulsed electric field in high slew-rate regime was investigated with the field ionization detection. The electric field necessary to ionize the Rydberg states was found to take discrete values successively depending on the slew rate. Specifically the slew-rate dependence of the ionization field varies with the quantum defect value of the states, i.e. with the energy position of the states relative to the adjacent manifold. This discrete transitional behavior of the ionization field observed for the first time is considered to be a manifestation of the strong coherence effect in the time evolution of the Rydberg states in pulsed electric field and opens a new effective way to stringently select a low-l state from the nearby states by field ionization.

  16. Electro-stimulation of Saccharomyces cerevisiae wine yeasts by Pulsed Electric Field and its effect on fermentation performance

    CERN Document Server

    Mattar, J; Nonus, M; Lebovka, N I; Zakhem, H El; Vorobiev, E

    2013-01-01

    The batch fermentation process, inoculated by pulsed electric field (PEF) treated wine yeasts (S. cerevisiae Actiflore F33), was studied. PEF treatment was applied to the aqueous yeast suspensions (0.12 % wt.) at the electric field strengths of E=100 and 6000 V/cm using the same pulse protocol (number of pulses of n=1000, pulse duration of ti=100 mks, and pulse repetition time of dt=100 ms). Electro-stimulation was confirmed by the observed growth of electrical conductivity of suspensions. The fermentation was running at 30{\\deg}C for 150 hours in an incubator with synchronic agitation. The obtained results clearly evidence the positive impact of PEF treatment on the batch fermentation process. Electro-stimulation resulted in improvement of such process characteristics as mass losses, consumption of soluble matter content ({\\deg}Brix) and synthesis of proteins. It also resulted in a noticeable acceleration of consumption of sugars at the initial stage of fermentation in the lag phase. At the end of the lag ph...

  17. Nonlinear imaging techniques for the observation of cell membrane perturbation due to pulsed electric field exposure

    Science.gov (United States)

    Moen, Erick K.; Beier, Hope T.; Thompson, Gary L.; Roth, Caleb C.; Ibey, Bennett L.

    2014-03-01

    Nonlinear optical probes, especially those involving second harmonic generation (SHG), have proven useful as sensors for near-instantaneous detection of alterations to orientation or energetics within a substance. This has been exploited to some success for observing conformational changes in proteins. SHG probes, therefore, hold promise for reporting rapid and minute changes in lipid membranes. In this report, one of these probes is employed in this regard, using nanosecond electric pulses (nsEPs) as a vehicle for instigating subtle membrane perturbations. The result provides a useful tool and methodology for the observation of minute membrane perturbation, while also providing meaningful information on the phenomenon of electropermeabilization due to nsEP. The SHG probe Di- 4-ANEPPDHQ is used in conjunction with a tuned optical setup to demonstrate nanoporation preferential to one hemisphere, or pole, of the cell given a single square shaped pulse. The results also confirm a correlation of pulse width to the amount of poration. Furthermore, the polarity of this event and the membrane physics of both hemispheres, the poles facing either electrode, were tested using bipolar pulses consisting of two pulses of opposite polarity. The experiment corroborates findings by other researchers that these types of pulses are less effective in causing repairable damage to the lipid membrane of cells.

  18. Real time kinetic flow cytometry measurements of cellular parameter changes evoked by nanosecond pulsed electric field.

    Science.gov (United States)

    Orbán, Csaba; Pérez-García, Esther; Bajnok, Anna; McBean, Gethin; Toldi, Gergely; Blanco-Fernandez, Alfonso

    2016-05-01

    Nanosecond pulsed electric field (nsPEF) is a novel method to increase cell proliferation rate. The phenomenon is based on the microporation of cellular organelles and membranes. However, we have limited information on the effects of nsPEF on cell physiology. Several studies have attempted to describe the effects of this process, however no real time measurements have been conducted to date. In this study we designed a model system which allows the measurement of cellular processes before, during and after nsPEF treatment in real time. The system employs a Vabrema Mitoplicator(TM) nsPEF field generating instrument connected to a BD Accuri C6 cytometer with a silicon tube led through a peristaltic pump. This model system was applied to observe the effects of nsPEF in mammalian C6 glioblastoma (C6 glioma) and HEK-293 cell lines. Viability (using DRAQ7 dye), intracellular calcium levels (using Fluo-4 dye) and scatter characteristics were measured in a kinetic manner. Data were analyzed using the FACSKin software. The viability and morphology of the investigated cells was not altered upon nsPEF treatment. The response of HEK-293 cells to ionomycin as positive control was significantly lower in the nsPEF treated samples compared to non-treated cells. This difference was not observed in C6 cells. FSC and SSC values were not altered significantly by the nsPEF treatment. Our results indicate that this model system is capable of reliably investigating the effects of nsPEF on cellular processes in real time. © 2016 International Society for Advancement of Cytometry.

  19. On the origin of the deviation from the first order kinetics in inactivation of microbial cells by pulsed electric fields

    CERN Document Server

    Lebovka, N I

    2003-01-01

    A computer model was developed for estimation of the kinetics of microbial inactivation by pulsed electric field. The model is based on the electroporation theory of individual membrane damage, where spherical cell geometry and distribution of cell sizes are assumed. The variation of microbial cell sizes was assumed to follow a statistical probability distribution of the Gaussian type. Surviving kinetics was approximated by Weibull equation. The dependencies of two Weibull parameters (shape textit{n} and time $tau $, respectively) versus electric field intensity E and width of cell diameters distribution was studied.

  20. Pulsed magnetic field excitation sensitivity of match-type electric blasting caps.

    Science.gov (United States)

    Parson, Jonathan; Dickens, James; Walter, John; Neuber, Andreas A

    2010-10-01

    This paper presents a study on energy deposition and electromagnetic compatibility of match-type electroexplosive devices (EEDs), which recently have found more usage in pulsed power environments with high electromagnetic interference (EMI) background. The sensitivity of these devices makes them dangerous to intended and unintended radiation produced by devices commonly used in pulsed power environments. Match-type EEDs have been found to be susceptible to such low levels of energy (7-8 mJ) that safe operation of these EEDs is vital when in use near devices that produce high levels of pulsed EMI. The scope of this paper is to provide an investigation that incorporates results of similar studies to provide detonation characteristics of these EEDs. The three topics included in this study are sensitivity testing, modeling of the thermodynamic heat propagation, and electromagnetic compatibility from pulsed electromagnetic radiation. The thermodynamic joule heating of the primary explosive has been modeled by a solution to the 1D heat equation. A simple pulsed generator, Marx generator with an inductive load, was used for the electromagnetic compatibility assessment of the coupled field between the pulse generator and shorted EED. The results of the electromagnetic compatibility assessment relate the resistive, inductive, and capacitive components of the pulse generator to the area of the shorted EED.

  1. Impact of pulsed-electric field and high-voltage electrical discharges on red wine microbial stabilization and quality characteristics.

    Science.gov (United States)

    Delsart, C; Grimi, N; Boussetta, N; Miot Sertier, C; Ghidossi, R; Vorobiev, E; Mietton Peuchot, M

    2016-01-01

    In this study, pulsed-electric fields (PEF) and high-voltage electrical discharges (HVED) are proposed as new techniques for the microbial stabilization of red wines before bottling. The efficiency of the treatment was then evaluated. PEF and HVED-treatments have been applied to wine for the inactivation of Oenococcus oeni CRBO 9304, O. oeni CRBO 0608, Pediococcus parvulus CRBO 2.6 and Brettanomyces bruxellensis CB28. Different treatment times (1, 2, 4, 6, 8 and 10 ms) were used at 20 kV cm(-1) for the PEF treatments and at 40 kV for the HVED treatments, which correspond to applied energies from 80 to 800 kJ l(-1) . The effects of the treatments on the microbial inactivation rate and on various characteristics of red wines (phenolic composition, chromatic characteristics and physico-chemical parameters) were measured. The application of PEF or HVED treatments on red wine allowed the inactivation of alteration yeasts (B. bruxellensis CB28) and bacteria (O. oeni CRBO 9304, O. oeni CRBO 0608 and P. parvulus CRBO 2.6). The electric discharges at 40 kV were less effective than the PEF even after 10 ms of treatments. Indeed, 4 ms of PEF treatment at 20 kV cm(-1) were sufficient to inactivate all micro-organisms present in the wines. Also, the use of PEF had no negative impact on the composition of wines compared to the HVED treatments. Contrary to PEF, the phenolics compounds were degraded after the HVED treatment and the physico-chemical composition of wine were modified with HVED. PEF technology seems to be an interesting alternative to stabilize microbiologically wines before bottling and without modifying their composition. This process offers many advantages for winemakers: no chemical inputs, low energy consumption (320 kJ l(-1) ), fast (treatment time of 4 ms) and athermal (ΔT ≈ 10°C). © 2015 The Society for Applied Microbiology.

  2. Influence of picosecond pulse electric field to invasive ability of cervical cancer

    Directory of Open Access Journals (Sweden)

    Li-mei WU

    2015-10-01

    Full Text Available Objective To investigate the influence of picosecond pulse electric field (psPEF to the invasive ability of cervical cancer. Methods The model of cervical cancer was reproduced in BALB/c nude mice (n=24, and they were randomly divided into four groups (n=6 when the xenografts had grown reaching a diameter of 0.8-1.0cm: control group (psPEF was not given, low field intensity group (50kV/cm, moderate field intensity group (60kV/cm and high field intensity group (70kV/cm. Seven days after the psPEF treatment, the histomorphological changes were observed with HE staining and transmission electron microscopy (TEM, the expressions of vascular endothelial growth factor (VEGF and matrix metalloproteinases-9 (MMP-9 were determined with immunohistochemical (IHC staining, and the changes in protein level of VEGF and MMP-9 were assessed with Western blotting. Results After psPEF treatment, the area of necrosis was found to be increased with an increase in psPEF intensity. With TEM different degrees of apoptosis and necrosis in tumor cells with an increase of psPEF intensity were found. IHC showed that the number of VEGF and MMP-9 positive cells in cancer tissue was decreased with an increase in psPEF intensity. The average optical density (AOD of VEGF and MMP-9 proteins decreased significantly in psPEF treatment groups compared with that in control group, and the AOD values in psPEF treatment groups decreased with an increase in psPEF intensity, and the decrease was statistically significant (P<0.05. Western blotting showed the expressive levels of VEGF and MMP-9 proteins declined gradually with an increase in psPEF intensity, and the difference between groups was statistically significant (P<0.05. Conclusion psPEF may have anti-cervical cancer effects by inhibiting the secretion of VEGF and MMP-9 and reducing the invasive ability of cervical cancer cells. DOI: 10.11855/j.issn.0577-7402.2015.09.03

  3. Inactivation of Pseudomonas putida by pulsed electric field treatment: a study on the correlation of treatment parameters and inactivation efficiency in the short-pulse range.

    Science.gov (United States)

    Frey, Wolfgang; Gusbeth, Christian; Schwartz, Thomas

    2013-10-01

    An important issue for an economic application of the pulsed electric field treatment for bacterial decontamination of wastewater is the specific treatment energy needed for effective reduction of bacterial populations. The present experimental study performed in a field amplitude range of 40 > E > 200 kV/cm and for a suspension conductivity of 0.01 = κ(e) > 0.2 S/m focusses on the application of short pulses, 25 ns > T > 10 μs, of rectangular, bipolar and exponential shape and was made on Pseudomonas putida, which is a typical and widespread wastewater microorganism. The comparison of inactivation results with calculations of the temporal and azimuthal membrane charging dynamics using the model of Pauly and Schwan revealed that for efficient inactivation, membrane segments at the cell equator have to be charged quickly and to a sufficiently high value, on the order of 0.5 V. After fulfilling this basic condition by an appropriate choice of pulse field strength and duration, the log rate of inactivation for a given suspension conductivity of 0.2 S/m was found to be independent of the duration of individual pulses for constant treatment energy expenditure. Moreover, experimental results suggest that even pulse shape plays a minor role in inactivation efficiency. The variation of the suspension conductivity resulted in comparable inactivation performance of identical pulse parameters if the product of pulse duration and number of pulses was the same, i.e., required treatment energy can be linearly downscaled for lower conductivities, provided that pulse amplitude and duration are selected for entire membrane surface permeabilization.

  4. Internal structure control of the TiO2 nanotubes and polysiloxane nanocomposites by nanosecond pulsed electric field

    Directory of Open Access Journals (Sweden)

    Ji-Won Lee

    2014-06-01

    Full Text Available A facile technique has been introduced for incorporating TiO2 nanotubes (TNTs in amorphous polysiloxane-based nanocomposite films and for linear and dense assembling of these TNTs (LATNTs under application of nanosecond pulse electric field. The use of a nanosecond electrical pulse enables the application of high electric power without causing dielectric breakdown, which occurs when DC/AC electric field is used, and the formation of LATNTs which anchor the resulting composite film planes. The properties of the nanocomposites were investigated using X-ray micro CT scanning, digital micrographs, UV–vis spectroscopy and electrical resistivity measurements. More than 5.5-fold UV–vis transmittance improvement was obtained by the polymer composite containing LATNTs (TNT 5.0 wt%. Such a composite exhibited a decreased electric resistivity of 3.08 × 107 Ω m compared to the case for randomly distributed TNTs (3.25 × 108 Ω m.

  5. Effect of High Electric Field on Lifetime Performance of Metalized Film Capacitor in Pulsed-power Applications

    Institute of Scientific and Technical Information of China (English)

    LI Hua; CHEN Yaohong; WANG Bowen; LI Zhiwei; ZHANG Qin; LIN Fuchang; HE Wei

    2013-01-01

    High energy density capacitor is a key device to power supply source for electromagnetic gun (EMG) system,and extending its lifetime is important for increasing the reliability of the power source.Working in high electric field could affect the capacitor lifetime,and this effect on metallized polypropylene film capacitors (MPPFCs) in pulsed-power applications is studied and presented.Experimental results show that the lifetime of MPPFCs decreases with the increasing peak value of charged electric field,and this decrease could be described by function (L/L0) ∝ (E/E0)-m,where,m=7.32.The lifetime of MPPFCs also decreases with the increase of the reversal coefficients in underdamped circuits,which could be described by (L/L0) ∝ (ln(1/K0)/(ln(1/K))-b,where,b=0.7.These results provide a basis for the lifetime prediction of MPPFCs in pulsed-power applications.

  6. Effect of Pulsed Electric Fields on the Flavour Profile of Red-Fleshed Sweet Cherries (Prunus avium var. Stella

    Directory of Open Access Journals (Sweden)

    Kristine Ann Gualberto Sotelo

    2015-03-01

    Full Text Available The aim of this research was to study the effect of pulsed electric fields (PEF on the flavour profile of red-fleshed sweet cherries (Prunus avium variety Stella. The cherry samples were treated at a constant pulse frequency of 100 Hz, a constant pulse width of 20 μs, different electric field strengths between 0.3 and 2.5 kV/cm and specific energy ranging from 31 to 55 kJ/kg. Volatile compounds of samples were analysed using an automated headspace solid phase microextraction (HS–SPME method coupled with gas chromatography-mass spectrometry (GC–MS. A total of 33 volatile compounds were identified with benzaldehyde, hexanal, (E-2-hexenal, (Z-2-hexen-1-ol, and benzyl alcohol being the predominant volatiles in different PEF-treated samples. Aldehydes namely butanal, octanal, 2-octenal, and nonanal, and (Z-2-hexen-1-ol increased significantly 24 h after PEF treatment at electric field strengths of more than 1.0 kV/cm. Samples incubated for 24 h after PEF treatment (S3 generated higher concentrations of volatiles than samples immediately after PEF treatments (S2. Quantitative results revealed that more flavour volatiles were released and associated with S3 samples after 24 h storage and S2 samples immediately after PEF both with the highest electric field intensities. Interestingly, this study found that the PEF treatments at the applied electric field strength and energy did not result in releasing/producing undesirable flavour compounds.

  7. Study of the selective effect on cells induced by nanosecond pulsed electric field with the resistor-capacitor circuit model

    Institute of Scientific and Technical Information of China (English)

    Xu Fei; Xiao Dengming; Li Zhaozhi

    2009-01-01

    A resistor-capacitor (RC) circuit model is proposed to study the effect of nanosecond pulsed electric field on cells according to the structure and electrical parameters of cells. After a nanosecond step field has been applied, the variation of voltages across cytomembrane and mitochondria membrane both in normal and in malignant cells are studied with this model. The time for selectively targeting the mitochondria membrane and malignant cell can be evaluated much easily with curves that show the variation of voltage across each membrane with time. Ramp field is the typical field applied in electrobiology. The voltages across each membrane induced by ramp field are analyzed with this model. To selectively target the mitochondria membrane, proper range of ramp slope is needed. It is relatively difficult to decide the range of a slope to selectively affect the malignant cell. Under some conditions, such a range even does not exist.

  8. Pulsed Electric Field inactivation of microbial cells: the use of ceramic layers to increase the efficiency of treatment

    Energy Technology Data Exchange (ETDEWEB)

    Pizzichemi, M. [Physics Department, University of Milano - Bicocca (Italy)

    2009-12-15

    The impact of Pulsed Electric Fields (PEF) on bacteria and plant or animal cells has been investigated since the early 1960s. High electric fields pulses (20-70 kV/cm, 1-10 mus) are reported to cause rupture of the cellular lipid membrane, through the mechanism of irreversible electroporation. Quantitative description of cell inactivation kinetics is based on the analysis of stability of lipid bilayers under electric fields and the thermal fluctuations associated with the production of pores. PEF has been successfully applied to inactivation of both Gram-positive and Gram-negative bacteria in many sorts of liquids, such as milk, fruit juices and liquid eggs. In all these media, the level of inactivation could reach the 5 Logs for an approximate range of pulses of 100-200, and an energy consumption of approx 10-100 kJ/kg. The advantages of PEF are the superior maintenance of functional and nutritional levels (if compared to traditional thermal treatment), continuous treatment and short processing times, while the current high costs of this technique make it more suitable for treatment of expensive media. We present a solution to the problem of volumes in PEF treatment through the use of high permittivity ceramics, while retaining the same inactivation efficiency and improving the duration of the electrodes.

  9. Pulse Field Gel Electrophoresis.

    Science.gov (United States)

    Sharma-Kuinkel, Batu K; Rude, Thomas H; Fowler, Vance G

    2016-01-01

    Pulse Field Gel Electrophoresis (PFGE) is a powerful genotyping technique used for the separation of large DNA molecules (entire genomic DNA) after digesting it with unique restriction enzymes and applying to a gel matrix under the electric field that periodically changes direction. PFGE is a variation of agarose gel electrophoresis that permits analysis of bacterial DNA fragments over an order of magnitude larger than that with conventional restriction enzyme analysis. It provides a good representation of the entire bacterial chromosome in a single gel with a highly reproducible restriction profile, providing clearly distinct and well-resolved DNA fragments.

  10. Sterilization of liquid foods by pulsed electric fields – an innovative ultra-high temperature process

    Directory of Open Access Journals (Sweden)

    Kai eReineke

    2015-05-01

    Full Text Available The intention of this study was to investigate the inactivation of endospores by a combined thermal and pulsed electric field (PEF treatment. Therefore, self-cultivated spores of Bacillus subtilis and commercial Geobacillus stearothermophilus spores with certified heat resistance were utilized. Spores of both strains were suspended in saline water (5.3 mS cm-1, skim milk (0.3% fat; 5.3 mS cm-1 and fresh prepared carrot juice (7.73 mS cm-1. The combination of moderate preheating (70-90 °C and an insulated PEF-chamber, combined with a holding tube (65 cm and a heat exchanger for cooling, enabled a rapid heat up to 105-140 °C (measured above the PEF chamber within 92.2-368.9 µs. To compare the PEF process with a pure thermal inactivation, each spore suspension was heat treated in thin glass capillaries and D-values from 90 to 130°C and its corresponding z-values were calculated. For a comparison of the inactivation data, F-values for the temperature fields of both processes were calculated by using Comsol Multiphysics combined with a Matlab routine.A preheating of saline water to 70 °C with a flow rate of 5 l h-1, a frequency of 150 Hz and an energy input of 226.5 kJ kg-1, resulted in a measured outlet temperature of 117 °C and a 4.67 log10 inactivation of Bacillus subtilis. The thermal process with identical F-value caused only a 3.71 log10 inactivation. This synergism of moderate preheating and PEF was even more pronounced for Geobacillus stearothermophilus spores in saline water. A preheating to 95 °C and an energy input of 144 kJ kg-1 resulted in an outlet temperature of 126 °C and a 3.28 log10 inactivation, whereas nearly no inactivation (0.2 log10 was achieved during the thermal treatment.Hence, the PEF technology was evaluated as an alternative ultra-high temperature process. However, for an industrial scale application of this process for sterilization, optimization of the treatment chamber design is needed to reduce the occurring

  11. Effects of Pulsed Electric Fields on DNA Synthesis in an Osteoblast-Like Cell Line (UMR-106)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The study of the bioeffects of electromagnetic fields (EMFs) is an important national task in biological physics. Using EMFs to treat bone diseases involves electrical technology, biology, and medicine. But the effects of EMFs are still controversial and the mechanisms are not yet clear. Therefore, more effect is needed to detect the effects at the cellular and molecular levels. This paper investigates the effects of low-energy, low-frequency pulsed capacitively coupled electric fields (PCCEFs) on DNA synthesis in UMR-106 osteoblast-like cells. The equipment can generate 25250Hz frequency, 0300V amplitude and 0.2ms pulse width signal. DNA synthesis is judged by the uptake of 3H-thymidine (3H-TdR). The results showed that the response of UMR-106 cells to electric field exposure are characterized by: (a) a frequency window for increased DNA synthesis, with a peak near 125Hz; (b) decreased synthesis with increasing electric intensity with repression at 100V/cm and 25Hz.

  12. Simultaneous investigation of ultrafast structural dynamics and transient electric field by sub-picosecond electron pulses

    Energy Technology Data Exchange (ETDEWEB)

    Li, Run-Ze; Zhu, Pengfei; Chen, Long; Chen, Jie, E-mail: jiec@sjtu.edu.cn, E-mail: jzhang1@sjtu.edu.cn; Sheng, Zheng-Ming; Zhang, Jie, E-mail: jiec@sjtu.edu.cn, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Cao, Jianming [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Physics Department and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States)

    2014-05-14

    The ultrafast structure dynamics and surface transient electric field, which are concurrently induced by laser excited electrons of an aluminum nanofilm, have been investigated simultaneously by the same transmission electron diffraction patterns. These two processes are found to be significantly different and distinguishable by tracing the time dependent changes of electron diffraction and deflection angles, respectively. This study also provides a practical means to evaluate simultaneously the effect of transient electric field during the study of structural dynamics under low pump fluence by transmission ultrafast electron diffraction.

  13. Metabolite profiling of phenolic and carotenoid contents in tomatoes after moderate-intensity pulsed electric field treatments.

    Science.gov (United States)

    Vallverdú-Queralt, Anna; Oms-Oliu, Gemma; Odriozola-Serrano, Isabel; Lamuela-Raventós, Rosa M; Martín-Belloso, Olga; Elez-Martínez, Pedro

    2013-01-01

    A metabolite profiling approach was used to study the effect of moderate-intensity pulsed electric field (MIPEF) treatments on the individual polyphenol and carotenoid contents of tomato fruit after refrigeration at 4°C for 24h. The MIPEF processing variables studied were electric field strength (from 0.4 to 2.0kV/cm) and number of pulses (from 5 to 30). Twenty four hours after MIPEF treatments, an increase was observed in hydroxycinnamic acids and flavanones, whereas flavonols, coumaric and ferulic acid-O-glucoside were not affected. Major changes were also observed for carotenoids, except for the 5-cis-lycopene isomer, which remain unchanged after 24h of MIPEF treatments. MIPEF treatments, conducted at 1.2kV/cm and 30 pulses, led to the greatest increases in chlorogenic (152%), caffeic acid-O-glucoside (170%) and caffeic (140%) acids. On the other hand, treatments at 1.2kV/cm and 5 pulses led to maximum increases of α-carotene, 9- and 13-cis-lycopene, which increased by 93%, 94% and 140%, respectively. Therefore, MIPEF could stimulate synthesis of secondary metabolites and contribute to production of tomatoes with high individual polyphenol and carotenoid contents.

  14. Measurement and simulation of Joule heating during treatment of B-16 melanoma tumors in mice with nanosecond pulsed electric fields.

    Science.gov (United States)

    Pliquett, Uwe; Nuccitelli, Richard

    2014-12-01

    Experimental evidence shows that nanosecond pulsed electric fields (nsPEF) trigger apoptosis in skin tumors. We have postulated that the energy delivered by nsPEF is insufficient to impart significant heating to the treated tissue. Here we use both direct measurements and theoretical modeling of the Joule heating in order to validate this assumption. For the temperature measurement, thermo-sensitive liquid crystals (TLC) were used to determine the surface temperature while a micro-thermocouple (made from 30 μm wires) was used for measuring the temperature inside the tissue. The calculation of the temperature distribution used an asymptotic approach with the repeated calculation of the electric field, Joule heating and heat transfer, and the subsequent readjustment of the electrical tissue conductivity. This yields a temperature distribution both in space and time. It can be shown that for the measured increase in temperature an unexpectedly high electrical conductivity of the tissue would be required, which was indeed found by using voltage and current monitoring during the experiment. Using impedance measurements within t(after)=50 μs after the pulse revealed a fast decline of the high conductivity state when the electric field ceases. The experimentally measured high conductance of a skin fold (mouse) between plate electrodes was about 5 times higher than those of the maximally expected conductance due to fully electroporated membrane structures (G(max)/G(electroporated))≈5. Fully electroporated membrane structure assumes that 100% of the membranes are conductive which is estimated from an impedance measurement at 10 MHz where membranes are capacitively shorted. Since the temperature rise in B-16 mouse melanoma tumors due to equally spaced (Δt=2 s) 300 ns-pulses with E=40 kV/cm usually does not exceed ΔΤ=3 K at all parts of the skin fold between the electrodes, a hyperthermic effect on the tissue can be excluded.

  15. Electrosensitization assists cell ablation by nanosecond pulsed electric field in 3D cultures.

    Science.gov (United States)

    Muratori, Claudia; Pakhomov, Andrei G; Xiao, Shu; Pakhomova, Olga N

    2016-03-18

    Previous studies reported a delayed increase of sensitivity to electroporation (termed "electrosensitization") in mammalian cells that had been subjected to electroporation. Electrosensitization facilitated membrane permeabilization and reduced survival in cell suspensions when the electric pulse treatments were split in fractions. The present study was aimed to visualize the effect of sensitization and establish its utility for cell ablation. We used KLN 205 squamous carcinoma cells embedded in an agarose gel and cell spheroids in Matrigel. A local ablation was created by a train of 200 to 600 of 300-ns pulses (50 Hz, 300-600 V) delivered by a two-needle probe with 1-mm inter-electrode distance. In order to facilitate ablation by engaging electrosensitization, the train was split in two identical fractions applied with a 2- to 480-s interval. At 400-600 V (2.9-4.3 kV/cm), the split-dose treatments increased the ablation volume and cell death up to 2-3-fold compared to single-train treatments. Under the conditions tested, the maximum enhancement of ablation was achieved when two fractions were separated by 100 s. The results suggest that engaging electrosensitization may assist in vivo cancer ablation by reducing the voltage or number of pulses required, or by enabling larger inter-electrode distances without losing the ablation efficiency.

  16. 1st World Congress on Electroporation and Pulsed Electric Fields in Biology, Medicine and Food & Environmental Technologies

    CERN Document Server

    Kramar, Peter

    2016-01-01

    This volume presents the proceedings of the 1st World Congress on Electroporation and Pulsed Electric Fields in Biology, Medicine and Food & Environmental Technologies (WC2015). The congress took place in Portorož, Slovenia, during the week of September 6th to 10th, 2015. The scientific part of the Congress covered different aspects of electroporation and related technologies and included the following main topics:   ·         Application of pulsed electric fields technology in food: challenges and opportunities ·         Electrical impedance measurement for assessment of electroporation yield ·         Electrochemistry and electroporation ·         Electroporation meets electrostimulation ·         Electrotechnologies for food and biomass treatment ·         Food and biotechnology applications ·         In vitro electroporation - basic mechanisms ·         Interfacial behaviour of lipid-assemblies, membranes and cells in electric f...

  17. Effect of pulsed electric field treatment during cold maceration and alcoholic fermentation on major red wine qualitative and quantitative parameters.

    Science.gov (United States)

    El Darra, Nada; Rajha, Hiba N; Ducasse, Marie-Agnès; Turk, Mohammad F; Grimi, Nabil; Maroun, Richard G; Louka, Nicolas; Vorobiev, Eugène

    2016-12-15

    This work studies the effect of pulsed electric field (PEF) treatment at moderate and high field strengths (E=0.8kV/cm & 5kV/cm) prior and during alcoholic fermentation (AF) of red grapes on improving different parameters of pre-treated extracts: pH, °Brix, colour intensity (CI), total polyphenols content (TPI) of Cabernet Sauvignon red wine. Similar trends were observed for treating grapes using moderate and high electric field strength on the enhancement of CI and TPI of the wine after AF. The application of PEF using moderate strengths at different times during cold maceration (CM) (0, 2 and 4days) was more efficient for treatment during CM. The treatment during AF showed lower extraction rate compared to treating during CM and prior to AF. Our results clearly show that the best time for applying the PEF-treatment through the red fermentation is during the CM step.

  18. Cavitation nanopore in the dielectric fluid in the inhomogeneous, pulsed electric fields

    CERN Document Server

    Pekker, M

    2014-01-01

    This paper discusses the nanopores emerging and developing in a liquid dielectric under the action of the ponderomotive electrostrictive forces in a nonuniform electric field. It is shown that the gradient of the electric field in the vicinity of the rupture (cavitation nanopore) substantially increases and determines whether the rupture grows or collapses. The cavitation rupture in the liquid (nanopore) tends to stretch along the lines of the original field. The mechanism of the breakdown associated with the generation of secondary ruptures in the vicinity of the poles of the nanopore is proposed. The estimations of the extension time for nanopore in water and oil (polar and nonpolar liquids, respectively) are presented. A new mechanism of nano- and subnanosecond breakdown in the insulating (transformer) oil that can be realized in the vicinity of water microdroplets in modern nanosecond high-voltage devices is considered

  19. Neuromuscular disruption with ultrashort electrical pulses

    Science.gov (United States)

    Pakhomov, Andrei; Kolb, Juergen F.; Joshi, Ravindra P.; Schoenbach, Karl H.; Dayton, Thomas; Comeaux, James; Ashmore, John; Beason, Charles

    2006-05-01

    Experimental studies on single cells have shown that application of pulsed voltages, with submicrosecond pulse duration and an electric field on the order of 10 kV/cm, causes sudden alterations in the intracellular free calcium concentration, followed by immobilization of the cell. In order to examine electrical stimulation and incapacitation with such ultrashort pulses, experiments on anesthetized rats have been performed. The effect of single, 450 nanosecond monopolar pulses have been compared with that of single pulses with multi-microsecond duration (TASER pulses). Two conditions were explored: 1. the ability to elicit a muscle twitch, and, 2. the ability to suppress voluntary movement by using nanosecond pulses. The second condition is relevant for neuromuscular incapacitation. The preliminary results indicate that for stimulation microsecond pulses are advantageous over nanosecond pulses, whereas for incapacitation, the opposite seems to apply. The stimulation effects seem to scale with electrical charge, whereas the disruption effects don't follow a simple scaling law. The increase in intensity (time of incapacitation) for a given pulse duration, is increasing with electrical energy, but is more efficient for nanosecond than for microsecond pulses. This indicates different cellular mechanisms for incapacitation, most likely subcellular processes, which have been shown to become increasingly important when the pulse duration is shortened into the nanosecond range. If further studies can confirm these initial results, consequences of reduced pulse duration are a reduction in weight and volume of the pulse delivery system, and likely, because of the lower required energy for neuromuscular incapacitation, reduced safety risks.

  20. High-voltage Pulsed Electric Field in.Food Industry%食品高压脉冲电场杀菌技术

    Institute of Scientific and Technical Information of China (English)

    袁丽佳; 何博; 姜彬; 尤涛

    2011-01-01

    High-voltage pulsed electric field is one of the most popular methods in food process. The mechanism of high-voltage pulsed electric field, the device of high-vo]tage pulsed electric field , and the application of it are introduced.%高压脉冲电场(high-voltage pulsed electric field,HPEF)杀菌技术是目前国际上最热门的食品加工技术之一,本文介绍了高压脉冲电场杀菌技术的基本机理,杀菌装置,以及对该技术在食品加工中应用的介绍。

  1. Nanosecond pulsed electric field induced dose dependent phosphatidylinositol-4,5-bisphosphate signaling and intracellular electro-sensitization.

    Science.gov (United States)

    Tolstykh, Gleb P; Tarango, Melissa; Roth, Caleb C; Ibey, Bennett L

    2017-03-01

    Previously, it was demonstrated that nanometer-sized pores (nanopores) are formed in outer cellular membranes after exposure to nanosecond electric pulses (nsEPs). We reported that plasma membrane nanoporation affects phospholipids of the cell membrane, culminating in cascading phosphoinositide phosphatidylinositol-4,5-bisphosphate (PIP2) intracellular signaling. In the current study, we show that nsEPs initiated electric field (EF) dose-dependent PIP2 hydrolysis and/or depletion from the plasma membrane. This process was confirmed using fluorescent optical probes of PIP2 hydrolysis: PLCδ-PH-EGFP and GFP-C1-PKCγ-C1a. The 50% maximum response occurs with a single 600ns pulse achieving an effective dose (ED50) of EF~8kV/cm within our model cell system. At 16.2kV/cm, the ED50 for the pulse width was 484ns. Reduction of the pulse width or EF amplitude gradually reduced the observed effect, but twenty 60ns 16.2kV/cm pulses produced an effect similar to a single 600ns pulse of the same amplitude. Propidium iodide (PI) uptake after the nsEP exposure confirmed a strong relationship between EF-induced plasma membrane impact and PIP2 depletion. These results have expanded our current knowledge of nsEPs dependent cell physiological effects, and serve as a basis for model development of new exposure standards, providing novel tools for drug independent stimulation and approaches to differential modulation of key cellular functions.

  2. Pulsed electric field-assisted modification of pectin from sugar beet pulp.

    Science.gov (United States)

    Ma, Sen; Wang, Zhong-he

    2013-02-15

    This current work is concerned with the modification of sugar beet pulp (SBP) pectin assisted by pulsed electric filed (PEF) without solvent. Pectin-arachates with degree of esterification (DE) ranging from 49 to 84 were prepared in one-step modification. The results showed that the DE of pectin derivatives increased significantly with the PEF intensity from 18 to 30 kV cm((1) and total specific energy input from 124 to 345 J mL((1). Evidence of modification of pectin was provided by FT-IR, X-ray diffraction patterns and NMR spectra. Thermogravimetric investigation of modified pectin indicated a higher thermal stability than the untreated one. Results revealed that PEF technology is a promising method for industrial manufacture of pectin derivatives.

  3. Attosecond streaking measurement of extreme ultraviolet pulses using a long-wavelength electric field

    Science.gov (United States)

    Saito, Nariyuki; Ishii, Nobuhisa; Kanai, Teruto; Watanabe, Shuntaro; Itatani, Jiro

    2016-01-01

    Long-wavelength lasers have great potential to become a new-generation drive laser for tabletop coherent light sources in the soft X-ray region. Because of the significantly low conversion efficiency from a long-wavelength light field to high-order harmonics, their pulse characterization has been carried out by measuring the carrier-envelope phase and/or spatial dependences of high harmonic spectra. However, these photon detection schemes, in general, have difficulty in obtaining information on the spectral phases, which is crucial to determine the temporal structures of high-order harmonics. Here, we report the first attosecond streaking measurement of high harmonics generated by few-cycle optical pulses at 1.7 μm from a BiB3O6–based optical parametric chirped-pulse amplifier. This is also the first demonstration of time-resolved photoelectron spectroscopy using high harmonics from a long-wavelength drive laser other than Ti:sapphire lasers, which paves the way towards ultrafast soft X-ray photoelectron spectroscopy. PMID:27752115

  4. Attosecond streaking measurement of extreme ultraviolet pulses using a long-wavelength electric field

    Science.gov (United States)

    Saito, Nariyuki; Ishii, Nobuhisa; Kanai, Teruto; Watanabe, Shuntaro; Itatani, Jiro

    2016-10-01

    Long-wavelength lasers have great potential to become a new-generation drive laser for tabletop coherent light sources in the soft X-ray region. Because of the significantly low conversion efficiency from a long-wavelength light field to high-order harmonics, their pulse characterization has been carried out by measuring the carrier-envelope phase and/or spatial dependences of high harmonic spectra. However, these photon detection schemes, in general, have difficulty in obtaining information on the spectral phases, which is crucial to determine the temporal structures of high-order harmonics. Here, we report the first attosecond streaking measurement of high harmonics generated by few-cycle optical pulses at 1.7 μm from a BiB3O6-based optical parametric chirped-pulse amplifier. This is also the first demonstration of time-resolved photoelectron spectroscopy using high harmonics from a long-wavelength drive laser other than Ti:sapphire lasers, which paves the way towards ultrafast soft X-ray photoelectron spectroscopy.

  5. Plasma Membrane Permeabilization by Trains of Ultrashort Electric Pulses

    Science.gov (United States)

    2009-01-01

    REFERENCES 1. Beebe, S.J., et al., Nanosecond Pulsed Electric Field (nsPEF) Effects on Cells and Tissues: Apoptosis Induction and Tumor Growth Inhibition...nanosecond pulsed electric field Bioelectromagnetics, 2007. 28: p. 655-663. 13. Gowrishankar, T.R. and J.C. Weaver, Electrical behavior and pore... electric field (nsPEF). Bioelectromagnetics, 2007. 28: p. 655- 663. 19. Nuccitelli, R., et al., A new pulsed electric field therapy for melanoma disrupts

  6. Development of double-pulse lasers ablation system for generating gold ion source under applying an electric field

    Science.gov (United States)

    Khalil, A. A. I.

    2015-12-01

    Double-pulse lasers ablation (DPLA) technique was developed to generate gold (Au) ion source and produce high current under applying an electric potential in an argon ambient gas environment. Two Q-switched Nd:YAG lasers operating at 1064 and 266 nm wavelengths are combined in an unconventional orthogonal (crossed-beam) double-pulse configuration with 45° angle to focus on a gold target along with a spectrometer for spectral analysis of gold plasma. The properties of gold plasma produced under double-pulse lasers excitation were studied. The velocity distribution function (VDF) of the emitted plasma was studied using a dedicated Faraday-cup ion probe (FCIP) under argon gas discharge. The experimental parameters were optimized to attain the best signal to noise (S/N) ratio. The results depicted that the VDF and current signals depend on the discharge applied voltage, laser intensity, laser wavelength and ambient argon gas pressure. A seven-fold increases in the current signal by increasing the discharge applied voltage and ion velocity under applying double-pulse lasers field. The plasma parameters (electron temperature and density) were also studied and their dependence on the delay (times between the excitation laser pulse and the opening of camera shutter) was investigated as well. This study could provide significant reference data for the optimization and design of DPLA systems engaged in laser induced plasma deposition thin films and facing components diagnostics.

  7. Comparison of phenolic compounds of orange juice processed by pulsed electric fields (PEF) and conventional thermal pasteurisation.

    Science.gov (United States)

    Agcam, E; Akyıldız, A; Akdemir Evrendilek, G

    2014-01-15

    Processing of orange juice by pulsed electric fields (PEF) and thermal pasteurisation was carried out to compare changes in total phenolic concentration, hydroxybenzoic acid, hydroxycinnamic acids, flavonols, flavones and flavonones before and after being stored at 4°C for 180days. Changes in the initial total phenolic concentration of the samples varied depending on the applied electric field intensity and thermal pasteurisation. Hesperidin and chlorogenic acids were detected as the most abounded flavonoid and phenolic acids in the orange juice, respectively. Except for syringic acid and neoeriocitrin, the concentration of the phenolic compounds indentified in the orange juice samples enhanced after the PEF or thermal pasteurisation. The samples treated with PEF had more stable flavonoids and phenolic acids than those treated with the thermal pasteurisation. The PEF-treated samples had higher sensory scores than the heat-treated samples.

  8. Pulsed plasmoid electric propulsion

    Science.gov (United States)

    Bourque, Robert F.; Parks, Paul B.; Tamano, Teruo

    1990-01-01

    A method of electric propulsion is explored where plasmoids such as spheromaks and field reversed configurations (FRC) are formed and then allowed to expand down a diverging conducting shell. The plasmoids contain a toroidal electric current that provides both heating and a confining magnetic field. They are free to translate because there are no externally supplied magnetic fields that would restrict motion. Image currents in the diverging conducting shell keep the plasmoids from contacting the wall. Because these currents translate relative to the wall, losses due to magnetic flux diffusion into the wall are minimized. During the expansion of the plasma in the diverging cone, both the inductive and thermal plasma energy are converted to directed kinetic energy producing thrust. Specific impulses can be in the 4000 to 20000 sec range with thrusts from 0.1 to 1000 Newtons, depending on available power.

  9. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production

    DEFF Research Database (Denmark)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G.

    2009-01-01

    on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline...... showed that environmental friendliness and the more natural products were seen as the main advantages, while they were concerned about body and health, the higher price of the products, the lack of information about the technologies and a general scepticism. The study also shows that North European...

  10. Time domain dielectric spectroscopy of nanosecond pulsed electric field induced changes in dielectric properties of pig whole blood.

    Science.gov (United States)

    Zhuang, Jie; Kolb, Juergen F

    2015-06-01

    The dielectric spectra of fresh pig whole blood in the β-dispersion range after exposure to 300-nanosecond pulsed electric fields (nsPEFs) with amplitude higher than the supra-electroporation threshold for erythrocytes were recorded by time domain reflectometry dielectric spectroscopy. The implications of the dielectric parameters on the dynamics of post-pulse pore development were discussed in light of the Cole-Cole relaxation model. The temporal development of the Cole-Cole parameters indicates that nsPEFs induced significant poration and swelling of erythrocytes within the first 5 min. The results also show that the majority of erythrocytes could not fully recover from supra-electroporation up to 30 min. The findings of this study suggest that time domain dielectric spectroscopy is a promising label-free and real-time physiological measuring technique for nsPEF-blood related biomedical applications, capable of following the conformational and morphological changes of cells.

  11. Nanosecond pulsed electric fields as a novel drug free therapy for breast cancer: an in vivo study.

    Science.gov (United States)

    Wu, Shan; Wang, Yu; Guo, Jinsong; Chen, Qunzhi; Zhang, Jue; Fang, Jing

    2014-02-28

    Nanosecond pulsed electric fields (nsPEFs) is a novel non-thermal approach to induce cell apoptosis. NsPEFs has been proven effective in treating several murine tumors, but few studies focus on its efficacy in treating human tumors. To determine if nsPEFs is equally effective in treatment of human breast cancer, 30 human breast cancer tumors across 30Balb/c (nu/nu) mice were exposed to 720 pulses of 100ns duration, at 4pulsespersecond and 30kV/cm. Two weeks after treatment, the growth of treated tumors was inhibited by 79%. Morphological changes of tumors were observed via a 3.0T clinical magnetic resonance imaging (MRI) system with a self-made surface coil. Pulsed tumors exhibited apoptosis evaluated by TUNEL staining, inhibition in Bcl-2 expression and decreased blood vessel density. Notably, CD34, vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) expression in treated tumors were strongly suppressed. To evaluate the might-be adverse effects of nsPEFs in healthy tissues, normal skin was treated exactly the same way as tumors, and pulsed skin showed no permanent damages. The results suggest nsPEFs is able to inhibit human breast cancer development and suppress tumor blood vessel growth, indicating nsPEFs may serve as a novel therapy for breast cancer in the future.

  12. Thresholds for phosphatidylserine externalization in Chinese hamster ovarian cells following exposure to nanosecond pulsed electrical fields (nsPEF.

    Directory of Open Access Journals (Sweden)

    Rebecca L Vincelette

    Full Text Available High-amplitude, MV/m, nanosecond pulsed electric fields (nsPEF have been hypothesized to cause nanoporation of the plasma membrane. Phosphatidylserine (PS externalization has been observed on the outer leaflet of the membrane shortly after nsPEF exposure, suggesting local structural changes in the membrane. In this study, we utilized fluorescently-tagged Annexin V to observe the externalization of PS on the plasma membrane of isolated Chinese Hamster Ovary (CHO cells following exposure to nsPEF. A series of experiments were performed to determine the dosimetric trends of PS expression caused by nsPEF as a function of pulse duration, τ, delivered field strength, ED, and pulse number, n. To accurately estimate dose thresholds for cellular response, data were reduced to a set of binary responses and ED50s were estimated using Probit analysis. Probit analysis results revealed that PS externalization followed the non-linear trend of (τ*ED (2(-1 for high amplitudes, but failed to predict low amplitude responses. A second set of experiments was performed to determine the nsPEF parameters necessary to cause observable calcium uptake, using cells preloaded with calcium green (CaGr, and membrane permeability, using FM1-43 dye. Calcium influx and FM1-43 uptake were found to always be observed at lower nsPEF exposure parameters compared to PS externalization. These findings suggest that multiple, higher amplitude and longer pulse exposures may generate pores of larger diameter enabling lateral diffusion of PS; whereas, smaller pores induced by fewer, lower amplitude and short pulse width exposures may only allow extracellular calcium and FM1-43 uptake.

  13. Treatment of cancer using pulsed electric field in combination with chemotherapeutic agents or genes.

    Science.gov (United States)

    Nishi, T; Dev, S B; Yoshizato, K; Kuratsu, J; Ushio, Y

    1997-03-01

    Electroporation is a standard laboratory technique originally developed for in vitro transfer of molecules into cells. It involves application of electrical pulses ranging from micro- to milliseconds that create transient pores in the cell membrane allowing intracellular access of exogenous molecules. This technique has been successfully applied to regress tumors in animal models by combining electroporation with chemotherapeutic agents--a process known as electrochemotherapy (ECT) which substantially enhance cytotoxicity of some antineoplastic agents. Recently ECT has moved into clinical arena and patients with cutaneous tumors and head and neck cancers have been treated very effectively with ECT. Parallel to ECT, a technique has also been developed which makes it possible to inject plasmid DNA and combine it with in vivo electroporation--electro--genetherapy (EGT)--to deliver in a highly efficient manner both marker and functional genes into target tissue and achieve gene expression. Thus, in vivo electroporation is contributing to the development of a new strategy for cancer treatment with both drugs and genes.

  14. Nanosecond pulsed electric field (nsPEF) treatment for hepatocellular carcinoma: a novel locoregional ablation decreasing lung metastasis.

    Science.gov (United States)

    Yin, Shengyong; Chen, Xinhua; Hu, Chen; Zhang, Xueming; Hu, Zhenhua; Yu, Jun; Feng, Xiaowen; Jiang, Kai; Ye, Shuming; Shen, Kezhen; Xie, Haiyang; Zhou, Lin; James Swanson, Robert; Zheng, Shusen

    2014-05-01

    Hepatocellular carcinoma (HCC) is a highly aggressive malignancy. Nanosecond pulsed electric field (nsPEF) is a new technology destroying tumor cells with a non-thermal high voltage electric field using ultra-short pulses. The study's aim was to evaluate the ablation efficacy of nsPEFs with human HCC cell lines and a highly metastatic potential HCC xenograft model on BALB/c nude mice. The in vivo study showed nsPEFs induced HCC cell death in a dose dependent manner. On the high metastatic hepatocellular carcinoma cell line (HCCLM3) xenograft mice model, tumor growth was inhibited significantly in nsPEF-treated- groups (single dose and multi-fractionated dose). Besides a local effect, the nsPEF treatment reduced pulmonary metastases. The nsPEFs also enhanced HCC cell phagocytosis by human macrophage cell (THP1) in vitro. The nsPEF is efficient in controlling HCC progression and reducing its metastasis. NsPEF treatment may elicit a host immune response against tumor cells. This study suggests nsPEF therapy could be used as a potential locoregional therapy for hepatocellular carcinoma.

  15. Effect of pulsed electric field on the proteolysis of cold boned beef M. Longissimus lumborum and M. Semimembranosus.

    Science.gov (United States)

    Suwandy, Via; Carne, Alan; van de Ven, Remy; Bekhit, Alaa El-Din A; Hopkins, David L

    2015-02-01

    The effects of pulsed electric field (PEF) and ageing (3, 7, 14 and 21 days) on the shear force, protein profile, and post-mortem proteolysis of beef loins (M. Longissimus lumborum, LL) and topsides (M. Semimembranosus, SM) were investigated using a range of pulsed electric field treatments [voltages (5 and 10 kV) and frequencies (20, 50, and 90 Hz)]. PEF treatment decreased the shear force of beef LL and SM muscles by up to 19%. The reduction in the shear force in the LL was not affected by the treatment intensity whereas the reduction in the SM was dependent on PEF frequency. PEF treated beef loins showed increased proteolysis, both early post-mortem and during subsequent post-mortem storage reflected by increased degradation of troponin-T and desmin. The most prominent troponin-T degradation was found in samples treated with 5 kV-90 Hz, 10 kV-20 Hz at day 3 and day 7 post-treatment in addition to 10 kV-50 Hz in subsequent post-treatment times. The degradation of desmin in PEF treated beef loins increased with ageing time.

  16. Effects of pre-fermentation and pulsed-electric-field treatment of primary sludge in microbial electrochemical cells.

    Science.gov (United States)

    Ki, Dongwon; Parameswaran, Prathap; Popat, Sudeep C; Rittmann, Bruce E; Torres, César I

    2015-11-01

    The aim of this study was to investigate the combination of two technologies - pulsed electric field (PEF) pre-treatment and semi-continuous pre-fermentation of primary sludge (PS) - to produce volatile fatty acids (VFAs) as the electron donor for microbial electrolysis cells (MECs). Pre-fermentation with a 3-day solids retention time (SRT) led to the maximum generation of VFAs, with or without pretreatment of the PS through pulsed-electric-fields (PEF). PEF treatment before fermentation enhanced the accumulation of the preferred VFA, acetate, by 2.6-fold. Correspondingly, MEC anodes fed with centrate from 3-day pre-fermentation of PEF-treated PS had a maximum current density ∼3.1 A/m(2), which was 2.4-fold greater than the control pre-fermented centrate. Over the full duration of batch MEC experiments, using pre-fermented centrate led to successful performance in terms of Coulombic efficiency (95%), Coulombic recovery (80%), and COD-removal efficiency (85%).

  17. Nutritional approaches and health-related properties of plant foods processed by high pressure and pulsed electric fields.

    Science.gov (United States)

    Sánchez-Moreno, Concepción; de Ancos, Begoña; Plaza, Lucía; Elez-Martínez, Pedro; Cano, M Pilar

    2009-06-01

    Consumers are more and more concerned about the nutritional and health-related characteristics of fruits and vegetables, as well as the safety of the food they eat. The processing of foods is becoming more sophisticated and diverse in response to the growing demand for quality foods. Consumers today expect food products to provide fresh-like appearance, convenience, variety, appropriate shelf-life and caloric content, reasonable cost, environmental soundness, high nutritional and functional quality. Nonthermal processing of fruit and vegetable has been revealed as a useful tool to extend their shelf-life and quality as well as to preserve their nutritional and functional characteristics. In the last ten years, there has been an increasing interest in nonthermal technologies as high pressure processing (HPP) and pulsed electric fields (PEF) to preserve fruit and vegetable products without the quality and nutritional damage caused by heat treatments. This review will contribute to inform many of the studies conducted to obtain a better understanding on the effects of some of these nonthermal processing technologies (high hydrostatic pressure and pulsed electric fields) applied to vegetable foods on their nutritional value and bioactive compounds related to health, including the results on micronutrient bioavailability studies and oxidative stress and inflammation biomarkers. These studies could contribute to select the most appropriate processing parameters to obtain safe, high-quality, nutritional, and functional vegetable food.

  18. Long Term Effects of Multiple DBD Pulses on Thin Liquid Layers Over Tissue: Reactive Fluences and Electric Fields

    Science.gov (United States)

    Tian, Wei; Kushner, Mark J.

    2014-10-01

    Atmospheric dielectric barrier discharges (DBDs) are used in treatment of tissue, often covered by thin liquid layers. The reactivity reaching the tissue depends on the plasma dose, composition and acidification of the liquid, and the cumulative delivery of electric fields through the liquid. In this paper, we report on a computational investigation of the interaction of DBDs with a thin liquid layer covering tissue over many minutes. We used nonPDPSIM, a 2-d model in which Poisson's equation, the electron temperature equation, transport equations for charged and neutral species and radiation transport are solved in both the gas and liquid. The liquid layer, 100's μm thick, is water with dissolved gases [O2aq (aq is aqueous), CO2aq], metal ions (Feaq2+ , Feaq3+) , and organics (RHaq) . Hundreds of pulses at 100 Hz are computed, followed by minutes of afterglow. In the liquid, transient radicals (OHaq, Haq) are produced during the discharge pulse and are consumed during the interpulse period. Terminal species (H2O2aq, O3aq) accumulate and diffuse to the tissue. Ions are dominated by NO3-aq, O2-aq and H3Oaq+.Production of HNO3aq and HOONOaq is assisted by O2aq for the first pulses and then O3aq. Accumulating nitric acid lowers the pH. RHaq consumes most reactive oxygen species in the early plasma treatment leaving Raq. With longer exposure, RHaq can be consumed, enabling more ROS to reach the tissue. The cumulative exposure of electric fields to the tissue depends on the increasing conductivity of the liquid. Work supported by DOE Office of Fusion Energy Science and NSF.

  19. Neuronal excitation and permeabilization by 200-ns pulsed electric field: An optical membrane potential study with FluoVolt dye.

    Science.gov (United States)

    Pakhomov, Andrei G; Semenov, Iurii; Casciola, Maura; Xiao, Shu

    2017-07-01

    Electric field pulses of nano- and picosecond duration are a novel modality for neurostimulation, activation of Ca(2+) signaling, and tissue ablation. However it is not known how such brief pulses activate voltage-gated ion channels. We studied excitation and electroporation of hippocampal neurons by 200-ns pulsed electric field (nsPEF), by means of time-lapse imaging of the optical membrane potential (OMP) with FluoVolt dye. Electroporation abruptly shifted OMP to a more depolarized level, which was reached within 10s), so cells remained above the resting OMP level for at least 20-30s. Activation of voltage-gated sodium channels (VGSC) enhanced the depolarizing effect of electroporation, resulting in an additional tetrodotoxin-sensitive OMP peak in 4-5ms after nsPEF. Omitting Ca(2+) in the extracellular solution did not reduce the depolarization, suggesting no contribution of voltage-gated calcium channels (VGCC). In 40% of neurons, nsPEF triggered a single action potential (AP), with the median threshold of 3kV/cm (range: 1.9-4kV/cm); no APs could be evoked by stimuli below the electroporation threshold (1.5-1.9kV/cm). VGSC opening could already be detected in 0.5ms after nsPEF, which is too fast to be mediated by the depolarizing effect of electroporation. The overlap of electroporation and AP thresholds does not necessarily reflect the causal relation, but suggests a low potency of nsPEF, as compared to conventional electrostimulation, for VGSC activation and AP induction. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Biological Effect and Related Applications of Pulsed Electric Fields%脉冲电场的生物效应与相关应用

    Institute of Scientific and Technical Information of China (English)

    段君; 刘雯; 郑雷蕾; 邓锋

    2011-01-01

    脉冲电场是一种高场强超短电脉冲,包含有从低频到高频的多种频率,具有上升时间短与作用时间短等不同于一般直流电与静电场的特点.大量研究认为,脉冲电场物理参数(脉宽、场强、频率)的改变对细胞产生不同的生物学效应,如细胞膜的电穿孔、钙离子释放、细胞增殖、基因表达增强等.脉冲电场其在临床中也有所应用.现将脉冲电场对细胞的生物作用机制和临床应用进行综述.%Pulsed electric fields are a kind of ultra-short, high-field electric pulse. They include several frequencies from low to high. Pulsed electric fields have three basic physical parameters. A lot of studies indicate that different biological effect on cells will occur with the change in pulsed electric fields physics parameters, such as , electroporation of cell membrane, release of Ca2 +, cells proliferation, and enhancement of gene expression. Now the cell biological mechanism of pulsed electric fields and their clinical applicalion are summarized.

  1. Nanosecond pulsed electric field (nsPEF) enhance cytotoxicity of cisplatin to hepatocellular cells by microdomain disruption on plasma membrane.

    Science.gov (United States)

    Yin, Shengyong; Chen, Xinhua; Xie, Haiyang; Zhou, Lin; Guo, Danjing; Xu, Yuning; Wu, Liming; Zheng, Shusen

    2016-08-15

    Previous studies showed nanosecond pulsed electric field (nsPEF) can ablate solid tumors including hepatocellular carcinoma (HCC) but its effect on cell membrane is not fully understood. We hypothesized nsPEF disrupt the microdomains on outer-cellular membrane with direct mechanical force and as a result the plasma membrane permeability increases to facilitate the small molecule intake. Three HCC cells were pulsed one pulse per minute, an interval longer than nanopore resealing time. The cationized ferritin was used to mark up the electronegative microdomains, propidium iodide (PI) for membrane permeabilization, energy dispersive X-ray spectroscopy (EDS) for the negative cell surface charge and cisplatin for inner-cellular cytotoxicity. We demonstrated that the ferritin marked-microdomain and negative cell surface charge were disrupted by nsPEF caused-mechanical force. The cell uptake of propidium and cytotoxicity of DNA-targeted cisplatin increased with a dose effect. Cisplatin gains its maximum inner-cellular cytotoxicity when combining with nsPEF stimulation. We conclude that nsPEF disrupt the microdomains on the outer cellular membrane directly and increase the membrane permeabilization for PI and cisplatin. The microdomain disruption and membrane infiltration changes are caused by the mechanical force from the changes of negative cell surface charge.

  2. Phase-sensitive optical pulse characterization on a chip via Spectral Phase Interferometry for Direct Electric-Field Reconstruction (SPIDER)

    CERN Document Server

    Pasquazi, Alessia; Park, Yongwoo; Little, Brent E; Chu, Sai T; Morandotti, Roberto; Azana, Jose; Moss, David J

    2014-01-01

    The recent introduction of coherent optical communications has created a compelling need for ultra-fast phase-sensitive measurement techniques operating at milliwatt peak power levels and in time scales ranging from sub-picoseconds to nanoseconds. Previous reports of ultrafast optical signal measurements in integrated platforms[8-10] include time-lens temporal imaging on a silicon chip[8,9] and waveguide-based Frequency-Resolved Optical Gating (FROG). Time-lens imaging is phase insensitive while waveguide-based FROG methods require the integration of long tuneable delay lines - still an unsolved challenge. Here, we report a device capable of characterizing both the amplitude and phase of ultrafast optical pulses with the aid of a synchronized incoherently-related clock pulse. It is based on a novel variation of Spectral Phase Interferometry for Direct Electric-Field Reconstruction (SPIDER)that exploits degenerate four-wave-mixing (FWM) in a CMOS compatible chip. We measure pulses with 1THz, and up to 100ps pu...

  3. PENERAPAN PULSED ELECTRIC FIELD PADA PASTEURISASI SARI BUAH APEL VARIETAS ANA: KAJIAN KARAKTERISTIK NILAI GIZI, SIFAT FISIK, SIFAT KIMIAWI DAN MIKROBIA TOTAL Application of Pulsed Electric Field in Pasteurization of Apple Juice of Ana Cultivar : Study on

    Directory of Open Access Journals (Sweden)

    La Choviya Hawa

    2012-05-01

    Full Text Available Apple juice, extracted from apple of ana cultivar , was pasteurized using a pulsed electric field (PEF method. The aimof this research was to analyze the changes on nutritional, physical and chemical properties and total microbes from apple juice after pasteurization. The research was conducted from July until Oktober 2009 located in Malang. The PEF treatment was carried out using treatment time variation for 10, 20, 30, 40, 50 and 60 seconds. Several parameters of vitamin A and C, water content, density, pH, total soluable solid and total microbes were observed. The results showed that PEF treatment did not significantly change nutritional, physical and chemical properties and total microbes after pasteurization with PEF in compared with no treatment pasteurization. The highest degradation was found in treatment time for 60 seconds, i.e. 93.53 %. ABSTRAK Sari buah apel, yang diekstrak dari apel varietas ana, dipasteurisasi dengan metode pulsed electric field (PEF. Tujuanpenelitian ini adalah untuk mengetahui perubahan karakteristik nilai gizi, sifat fisik, kimiawi dan total mikrobia sari buah apel sesudah dipasteurisasi. Penelitian dilaksanakan bulan Juli sampai dengan Oktober 2009 di Malang. Penelitian ini menggunakan variasi waktu pengolahan 10, 20, 30, 40, 50 dan 60 detik. Parameter pengamatan yaitu vitamin A dan C, kadar air, berat jenis, pH, total padatan terlarut dan total mikrobia. Hasil penelitian menunjukkan bahwa nilai gizi, sifat fisik dan kimiawi dari sari apel  tidak mengalami perubahan signifikan dibandingkan sari apel tanpa perlakuan PEF. Penurunan total mikrobia terbesar pada waktu perlakuan 60 detik dengan efektivitas pembunuhan sebesar 93,53%.

  4. Pulsed DC Electric Field-Induced Differentiation of Cortical Neural Precursor Cells.

    Directory of Open Access Journals (Sweden)

    Hui-Fang Chang

    Full Text Available We report the differentiation of neural stem and progenitor cells solely induced by direct current (DC pulses stimulation. Neural stem and progenitor cells in the adult mammalian brain are promising candidates for the development of therapeutic neuroregeneration strategies. The differentiation of neural stem and progenitor cells depends on various in vivo environmental factors, such as nerve growth factor and endogenous EF. In this study, we demonstrated that the morphologic and phenotypic changes of mouse neural stem and progenitor cells (mNPCs could be induced solely by exposure to square-wave DC pulses (magnitude 300 mV/mm at frequency of 100-Hz. The DC pulse stimulation was conducted for 48 h, and the morphologic changes of mNPCs were monitored continuously. The length of primary processes and the amount of branching significantly increased after stimulation by DC pulses for 48 h. After DC pulse treatment, the mNPCs differentiated into neurons, astrocytes, and oligodendrocytes simultaneously in stem cell maintenance medium. Our results suggest that simple DC pulse treatment could control the fate of NPCs. With further studies, DC pulses may be applied to manipulate NPC differentiation and may be used for the development of therapeutic strategies that employ NPCs to treat nervous system disorders.

  5. The effect of pulse field-strength on electric-field stimulated biosorption of uranium by Kluyveromyces-marxianus IMB3

    Energy Technology Data Exchange (ETDEWEB)

    Bustard, M.; Donnellan, N.; Rollan, A.; McHale, L.; McHale, A.P. [Ulster Univ., Coleraine (United Kingdom). Biotechnology Research Group

    1996-04-01

    Improved biosorption of uranium by Kluyveromyces marxianus IMB3 biomass was achieved by increasing the electric field strength of delivered pulses from 1.25kV/cm to 2.5kV/cm. Although this had little or no effect on the maximum biosorption capacity (q(max)), at low concentrations of uranium the amount bound to the biomass increased from 70 to 140mg uranium/g biomass. Significant increases in the maximum biosorption capacities (119-180 mg uranium/g biomass) were observed when the pulse field strength was increased from 2.5kV/cm to 3.25kV/cm. (Author).

  6. Effect of pulsed electric field (PEF) on structures and antioxidant activity of soybean source peptides-SHCMN.

    Science.gov (United States)

    Lin, Songyi; Liang, Rong; Li, Xingfang; Xing, Jie; Yuan, Yuan

    2016-12-15

    Recently, high-intensity pulsed electric field (PEF) has successfully used in improvement of antioxidant activity. Ser-His-Cys-Met-Asn (SHCMN) obtained from soybean protein was chosen to investigate the phenomenon of antioxidant activity improvement. Effects of PEF treatment on antioxidant activity of SHCMN were evaluated by DPPH radical inhibition. Nuclear magnetic resonance (NMR), mid-infrared (MIR), circular dichroism (CD) were used to analyze structures of SHCMN. Two-factor-at-a-time results show that DPPH radical inhibition of SHCMN is significantly (Pelectric field intensity of 5kV/cm, pulse frequency of 2400Hz, and retention time of 2h. In addition, MIR and NMR spectra show that the basic structure of peptides SHCMN is stable by PEF treatment. But the secondary structures (α-helix, β-turn, and random coil) can be affected and zeta potential of PEF-treated SHCNM was reduced to 0.59±0.03mV. The antioxidant activity improvement of SHCMN might result from the changes of secondary structures and zeta potential.

  7. Selective extraction of intracellular components from the microalga Chlorella vulgaris by combined pulsed electric field-temperature treatment.

    Science.gov (United States)

    Postma, P R; Pataro, G; Capitoli, M; Barbosa, M J; Wijffels, R H; Eppink, M H M; Olivieri, G; Ferrari, G

    2016-03-01

    The synergistic effect of temperature (25-65 °C) and total specific energy input (0.55-1.11 kWh kgDW(-1)) by pulsed electric field (PEF) on the release of intracellular components from the microalgae Chlorella vulgaris was studied. The combination of PEF with temperatures from 25 to 55 °C resulted in a conductivity increase of 75% as a result of cell membrane permeabilization. In this range of temperatures, 25-39% carbohydrates and 3-5% proteins release occurred and only for carbohydrate release a synergistic effect was observed at 55 °C. Above 55 °C spontaneous cell lysis occurred without PEF. Combined PEF-temperature treatment does not sufficiently disintegrate the algal cells to release both carbohydrates and proteins at yields comparable to the benchmark bead milling (40-45% protein, 48-58% carbohydrates).

  8. Water Sterilization by Pulsed Electric Field(PEF)%高压脉冲电场水中杀菌

    Institute of Scientific and Technical Information of China (English)

    张悦; 李国锋; 李杰

    2007-01-01

    采用板-板式电极结构,短脉冲高压电源供电,形成高压脉冲电场(pulsed electric field, PEF),对水体中大肠杆菌进行灭活处理.探讨了PEF作用下大肠杆菌失活动力学方程.研究表明:8 kV/cm PEF作用下大肠杆菌灭活效果随脉冲时间增加而提高.PEF灭活动力学方程为lgS(t)=-0.417 45 ln(1+0.003 99 t),形式与Alvarez模型一致.

  9. Electron-ion-ion coincidence experiments for photofragmentation of polyatomic molecules using pulsed electric fields: treatment of random coincidences

    CERN Document Server

    Pruemper, G

    2007-01-01

    In molecular photofragmentation processes by soft X-rays, a number of ionic fragments can be produced, each having a different abundance and correlation with the emitted electron kinetic energy. For investigating these fragmentation processes, electron-ion and electron-ion-ion coincidence experiments, in which the kinetic energy of electrons are analyzed using an electrostatic analyzer while the mass of the ions is analyzed using a pulsed electric field, are very powerful. For such measurements, however, the contribution of random coincidences is substantial and affects the data in a non-trivial way. Simple intuitive subtraction methods cannot be applied. In the present paper, we describe these electron-ion and electron-ion-ion coincidence experiments together with a subtraction method for the contribution from random coincidences. We provide a comprehensive set of equations for the data treatment, including equations for the calculation of error-bars. We demonstrate the method by applying it to the fragmenta...

  10. Pectin methyl esterase and natural microflora of fresh mixed orange and carrot juice treated with pulsed electric fields.

    Science.gov (United States)

    Rodrigo, D; Barbosa-Cánovas, G V; Martínez, A; Rodrigo, M

    2003-12-01

    The effects of pulsed electric fields (PEFs) on pectin methyl esterase (PME), molds and yeast, and total flora in fresh (nonpasteurized) mixed orange and carrot juice were studied. The PEF effect was more extensive when juices with high levels of initial PME activity were subjected to treatment and when PEF treatment (at 25 kV/cm for 340 micros) was combined with a moderate temperature (63 degrees C), with the maximum level of PME inactivation being 81.4%. These conditions produced 3.7 decimal reductions in molds and yeast and 2.4 decimal reductions in total flora. Experimental inactivation data for PME, molds and yeast, and total flora were fitted to Bigelow, Hülsheger, and Weibull inactivation models by nonlinear regression. The best fit (lowest mean square error) was obtained with the Weibull model.

  11. An investigation into the cumulative breakdown process of polymethylmethacrylate in quasi-uniform electric field under nanosecond pulses

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Liang; Cang Su, Jian; Bo Zhang, Xi; Feng Pan, Ya; Min Wang, Li; Peng Fang, Jin; Sun, Xu; Lui, Rui [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, P.O. Box 69 Branch 13, Xi' an 710024 (China)

    2013-08-15

    A group of complete images on the discharge channel developed in PMMA in quasi-uniform electric field under nanosecond pulses are observed with an on-line transmission microscope. The characteristics of the cumulative breakdown process are also generalized, which include initiating from the vicinity of the cathode, developing to the anode with a branch-like shape, and taking on a wormhole appearance when final breakdown occurs. The concluded characteristics are explained by referring to the conceptions of “low density domain” and “free radical” and considering the initial discharge channel as a virtual needle. The characteristics are helpful for designers to enhance the lifetime of insulators employed on a nanosecond time scale.

  12. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production

    DEFF Research Database (Denmark)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G.

    2009-01-01

    . Participants were introduced to the HPP and PEF technologies and then to the effect of the two new technologies on two specific product categories: juice and baby food. The transcribed data was content analysed and the coded data was transformed into diagrams using UCINET 5 and NETDRAW. The results show......The success of new food processing technologies is highly dependent on consumers' acceptance. The purpose of this paper is to study consumers' perceptions of two new processing technologies and food products produced by means of these novel technologies. To accomplish this, a qualitative study...... on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline...

  13. Impact of high-intensity pulsed electric fields on bioactive compounds in Mediterranean plant-based foods.

    Science.gov (United States)

    Elez-Martínez, Pedro; Soliva-Fortuny, Robert; Martín-Belloso, Olga

    2009-05-01

    Novel non-thermal processing technologies such as high-intensity pulsed electric field (HIPEF) treatments may be applied to pasteurize plant-based liquid foods as an alternative to conventional heat treatments. In recent years, there has been an increasing interest in HIPEF as a way of preserving and extending the shelf-life of liquid products without the quality damage caused by heat treatments. However, less attention has been paid to the effects of HIPEF on minor constituents of these products, namely bioactive compounds. This review is a state-of-the-art update on the effects of HIPEF treatments on health-related compounds in plants of the Mediterranean diet such as fruit juices, and Spanish gazpacho. The relevance of HIPEF-processing parameters on retaining plant-based bioactive compounds will be discussed.

  14. Optimization of Combined Pulsed Electric Fields and Mild Temperature Processing Conditions for Red Apple Juice Polyphenol Oxidase and Peroxidase Inactivation

    Directory of Open Access Journals (Sweden)

    Wendy Katiyo

    2014-05-01

    Full Text Available The effect on Polyphenol Oxidase (PPO and Peroxidase (POD enzyme activity in red apple juice was evaluated after combined Pulsed Electric Fields (PEF and mild temperature processing using a response surface methodology. Changes in color were also analyzed and compared with thermally treated and unpasteurized juices. The studied factors were electric field strength (10-30 kV/cm, treatment time (200-1000 µs and temperature (20-60°C. A significant second-order response function covering the whole range of experimental conditions was obtained for each enzyme. Treatments conducted at 30 kV/cm, 1000 µs and 60°C led to red apple juice with the lowest residual enzyme activity (0.04 and 0.16 for PPO and POD, respectively. Overall change in color was significantly lower (p<0.05, in comparison with severe thermal treatments. It was feasible to achieve comparable enzyme inactivation and better preserve natural juice color by this hurdle technique.

  15. Synergistic effect of nanosecond pulsed electric field combined with low-dose of pingyangmycin on salivary adenoid cystic carcinoma.

    Science.gov (United States)

    Qi, Wei; Guo, Jinsong; Wu, Shan; Su, Bo; Zhang, Lei; Pan, Jie; Zhang, Jue

    2014-05-01

    Adenoid cystic carcinoma (ACC) is one of the most common malignant neoplasms in salivary glands. To evaluate the therapeutic effects of nanosecond pulsed electric field (nsPEF) combined with pingyangmycin (PYM) on salivary gland adenoid cystic carcinoma (SACC), ACC high metastatic cell line (SACC-LM) and low metastatic cell line (SACC‑83) were tested by CCK-8 assay, cell clonogenic assay, flow cytometry and Transwell assay. Extracellular matrix metalloproteinase inducer (EMMPRIN) expression was tested by western blotting to verify the synergistic mechanism of nsPEF and PYM. The results showed that nsPEF inhibited the cell proliferation of both cell lines, and the inhibitory effect was strongly associated with time and electrical field strength. Moreover, PYM combined with nsPEF may enhance the suppression effect significantly, even at a very low dose (0.01 µg/ml). The synergistic effects may contribute to the downregulation of EMMPRIN expression resulting from the application of nsPEF. For SACC, nsPEF combined with chemotherapy agents may be a valuable strategy not only to improve the treatment effect and prognosis, but also to reduce the side-effects of chemotherapy.

  16. Temperature-mediated variations in cellular membrane fatty acid composition of Staphylococcus aureus in resistance to pulsed electric fields.

    Science.gov (United States)

    Wang, Lang-Hong; Wang, Man-Sheng; Zeng, Xin-An; Liu, Zhi-Wei

    2016-08-01

    Effects of growth temperature on cell membrane fatty acid composition, fluidity and lethal and sublethal injury by pulsed electric fields (PEF) in Staphylococcus aureus ATCC 43300 (S. aureus) in the stationary phase were investigated. Analysis of the membrane fatty acids by gas chromatography-mass spectrometry (GC-MS) revealed that branched chain fatty acids (iso C14:0, iso C15:0, anteiso C15:0 and anteiso C17:0) and straight chain fatty acids (C12:0, C14:0, C16:0, C17:0 and C18:0) were primary constituents in the membrane. The S. aureus changed its membrane fatty acid composition and its overall fluidity when exposed to different temperatures. The PEF lethal and sublethal effects were assessed, and results suggested that the degree of inactivation depended on the cell membrane structure, electric field strength and treatment time. The PEF inactivation kinetics including lethal and sublethal injury fractions were fitted with non-linear Weibull distribution, suggesting that inactivation of the first log cycle of S. aureus population was significantly affected by growth temperature, and the membrane of cells became more fluid, and easier to induce electroportion in low temperatures. Moreover, the morphology of S. aureus cells were investigated by electron microscopy, showing that various temperature-modified cells were distorted to differing extents and some even collapsed due to deep irreversible electroporation after PEF treatment.

  17. Consumer acceptance of high-pressure processing and pulsed-electric-field

    DEFF Research Database (Denmark)

    Olsen, Nina Veflen; Grunert, Klaus G.; Sonne, Anne-Mette

    2010-01-01

    has to offer, do not necessarily guarantee the success of a product in the market place. Consumer acceptance depends on whether consumers perceive that there are specific benefits associated with the product. This review focuses specifically on how high-pressure processing (HPP) and pulsed...

  18. Uniform and non-uniform modes of nanosecond-pulsed dielectric barrier discharge in atmospheric air: fast imaging and spectroscopic measurements of electric field.

    Science.gov (United States)

    Liu, Chong; Dobrynin, Danil; Fridman, Alexander

    2014-06-25

    In this study, we report experimental results on fast ICCD imaging of development of nanosecond-pulsed dielectric barrier discharge (DBD) in atmospheric air and spectroscopic measurements of electric field in the discharge. Uniformity of the discharge images obtained with nanosecond exposure times were analyzed using chi-square test. The results indicate that DBD uniformity strongly depends on applied (global) electric field in the discharge gap, and is a threshold phenomenon. We show that in the case of strong overvoltage on the discharge gap (provided by fast rise times), there is transition from filamentary to uniform DBD mode which correlates to the corresponding decrease of maximum local electric field in the discharge.

  19. Thermal properties of milk fat, xanthine oxidase, caseins and whey proteins in pulsed electric field-treated bovine whole milk.

    Science.gov (United States)

    Sharma, Pankaj; Oey, Indrawati; Everett, David W

    2016-09-15

    Thermodynamics of milk components (milk fat, xanthine oxidase, caseins and whey proteins) in pulsed electric field (PEF)-treated milk were compared with thermally treated milk (63 °C for 30 min and 73 °C for 15s). PEF treatments were applied at 20 or 26 kV cm(-1) for 34 μs with or without pre-heating of milk (55 °C for 24s), using bipolar square wave pulses in a continuous mode of operation. PEF treatments did not affect the final temperatures of fat melting (Tmelting) or xanthine oxidase denaturation (Tdenaturation), whereas thermal treatments increased both the Tmelting of milk fat and the Tdenaturation for xanthine oxidase by 2-3 °C. Xanthine oxidase denaturation was ∼13% less after PEF treatments compared with the thermal treatments. The enthalpy change (ΔH of denaturation) of whey proteins decreased in the treated-milk, and denaturation increased with the treatment intensity. New endothermic peaks in the calorimetric thermograms of treated milk revealed the formation of complexes due to interactions between MFGM (milk fat globule membrane) proteins and skim milk proteins. Evidence for the adsorption of complexes onto the MFGM surface was obtained from the increase in surface hydrophobicity of proteins, revealing the presence of unfolded hydrophobic regions.

  20. Exploring the use of natural antimicrobial agents and pulsed electric fields to control spoilage bacteria during a beer production process.

    Science.gov (United States)

    Galvagno, M A; Gil, G R; Iannone, L J; Cerrutti, P

    2007-01-01

    Different natural antimicrobials affected viability of bacterial contaminants isolated at critical steps during a beer production process. In the presence of 1 mg/ml chitosan and 0.3 mg/ml hops, the viability of Escherichia coli in an all malt barley extract wort could be reduced to 0.7 and 0.1% respectively after 2 hour- incubation at 4 degrees C. The addition of 0.0002 mg/ml nisin, 0.1 mg/ml chitosan or 0.3 mg/ml hops, selectively inhibited growth of Pediococcus sp. in more than 10,000 times with respect to brewing yeast in a mixed culture. In the presence of 0.1 mg ml chitosan in beer, no viable cells of the thermoresistant strain Bacillus megaterium were detected. Nisin, chitosan and hops increased microbiological stability during storage of a local commercial beer inoculated with Lactobacillus plantarum or Pediococcus sp. isolated from wort. Pulsed Electric Field (PEF) (8 kV/cm, 3 pulses) application enhanced antibacterial activity of nisin and hops but not that of chitosan. The results herein obtained suggest that the use of these antimicrobial compounds in isolation or in combination with PEF would be effective to control bacterial contamination during beer production and storage.

  1. Disintegration efficiency of pulsed electric field induced effects on onion (Allium cepa L.) tissues as a function of pulse protocol and determination of cell integrity by ¹H-NMR relaxometry.

    Science.gov (United States)

    Ersus, Seda; Oztop, Mecit Halil; McCarthy, Michael J; Barrett, Diane M

    2010-09-01

    The influence of electrical pulse protocol parameters on cell rupture of onion tissues was investigated in order to improve fundamental understanding and to enhance the processing of plant tissues with pulsed electric fields (PEFs). The impact of PEF parameters on cell integrity of 20 mm dia, 4-mm thick disks of Don Victor onions (Allium cepa L.) was determined by ion leakage measurements. Electric field strength, pulse width, total pulse duration, and frequency effects were determined in relation to their effects on cell damage as a function of pulse protocol. Electric field strengths up to 500 V/cm increased the damage efficiency but there was no significant difference in efficiency beyond this field strength. Larger pulse widths increased the degree of tissue disintegration at a constant pulse number. Higher PEF efficiency was achieved with shorter pulse widths and a larger number of pulses at a constant total treatment time. Lower frequencies caused a greater degree of disintegration at constant number of pulses. ¹H-NMR experiments were performed to determine the proton relaxation components of the PEF-treated onion samples and to obtain cell damage information nondestructively. Paramagnetic ion uptake by the onion sample was used to identify different proton relaxation components. Five different proton relaxation components were observed and changes in the 2 components representing different proton environments showed high correlations with ion leakage results (R²= 0.99), indicating that T(2) distributions can be used to obtain information about cell membrane integrity in PEF-treated samples. 1H-NMR proved to be an effective method for nondestructive quantification of cell membrane rupture in onions.

  2. Inactivation of Escherichia coli, Saccharomyces cerevisiae, and Lactobacillus brevis in Low-fat Milk by Pulsed Electric Field Treatment: A Pilot-scale Study.

    Science.gov (United States)

    Lee, Gun Joon; Han, Bok Kung; Choi, Hyuk Joon; Kang, Shin Ho; Baick, Seung Chun; Lee, Dong-Un

    2015-01-01

    We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 μs were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The inactivation curves of the test microorganisms were biphasic with an initial lag phase (or shoulder) followed by a phase of rapid inactivation. PEF treatments with a total pulse energy of 200 kJ/L resulted in a 4.5-log reduction in E. coli, a 4.4-log reduction in L. brevis, and a 6.0-log reduction in S. cerevisiae. Total pulse energies of 200 and 250 kJ/L resulted in greater than 5-log reductions in microbial counts in stored PEF-treated milk, and the growth of surviving microorganisms was slow during storage for 15 d at 4℃. PEF treatment did not change milk physical properties such as pH, color, or particle-size distribution (pelectric-field strength of 10 kV/cm can be used to pasteurize low-fat milk.

  3. Pulsed electric field processing of different fruit juices: impac of pH and temperature on inactivation of spoilage and pathogenic micro-organisms

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Nierop Groot, M.N.; Nederhoff, A.L.; Boekel, van M.A.J.S.; Matser, A.M.; Mastwijk, H.C.

    2014-01-01

    Pulsed electrical field (PEF) technology can be used for the inactivation of micro-organisms and therefore for preservation of food products. It is a mild technology compared to thermal pasteurization because a lower temperature is used during processing, leading to a better retention of the quality

  4. Evaluation of microbial stability, bioactive compounds, physicochemical properties, and consumer acceptance of pomegranate juice processed in a commercial scale pulsed electric field system

    Science.gov (United States)

    This paper investigated the feasibility for pasteurizing raw pomegranate juice in a commercial scale pulsed electric field (PEF) system. The juice was processed in a commercial scale PEF processing system at 35 and 38 kV/cm for 281 µs at 55 degree C with a flow rate of 100 L/h. Effect of PEF process...

  5. Inactivation of E. coli O157:H7 and nonpathogenic E. coli in strawberry juice by pulsed electric field, sodium benzoate, potassium sorbate, and citric acid

    Science.gov (United States)

    Introduction: Current regulations require that juice processors effect a 5 log CFU/ml reduction of a target pathogen prior to distributing products. Whereas thermal pasteurization reduces the sensory characteristics of juice by altering flavor components, pulsed electric field (PEF) treatment may ...

  6. Behavior of pulsed electric field injured Escherichia coli O157:H7 cells in apple juice amended with pyruvate and catalase

    Science.gov (United States)

    Pulse Electric Field (PEF) treatment has been used to inactivate bacteria in liquid foods. However, information on the behavior of PEF injured Escherichia coli bacteria in media during storage at 5 and 23C are limited. In this study, we investigated the fate of E. coli O157:H7 cells at 6.8 log CFU/m...

  7. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice. Part I: Impact on overall quality attributes

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Mastwijk, H.C.; Knol, J.J.; Quataert, M.C.J.; Vervoort, L.; Plancken, van der I.; Hendrickx, M.E.; Matser, A.M.

    2011-01-01

    Mild heat pasteurization, high pressure processing (HP) and pulsed electric field (PEF) processing of freshly squeezed orange juice were comparatively evaluated examining their impact on microbial load and quality parameters immediately after processing and during two months of storage. Microbial co

  8. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice: Part II: Impact on specific chemical and biochemical quality parameters

    NARCIS (Netherlands)

    Vervoort, L.; Plancken, van der I.; Grauwet, T.; Timmermans, R.A.H.; Mastwijk, H.C.; Matser, A.M.; Hendrickx, M.E.; Loey, van A.

    2011-01-01

    The impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurization of orange juice was compared on a fair basis, using processing conditions leading to an equivalent degree of microbial inactivation. Examining the effect on specific chemical and biochemical

  9. Effects of pulsed electric field treatment on enhancing lipid recovery from the microalga, Scenedesmus.

    Science.gov (United States)

    Lai, YenJung Sean; Parameswaran, Prathap; Li, Ang; Baez, Maria; Rittmann, Bruce E

    2014-12-01

    Chloroform and methanol are superior solvents for lipid extraction from photosynthetic microorganisms, because they can overcome the resistance offered by the cell walls and membranes, but they are too toxic and expensive to use for large-scale fuel production. Biomass from the photosynthetic microalga Scenedesmus, subjected to a commercially available pre-treatment technology called Focused-Pulsed® (FP), yielded 3.1-fold more crude lipid and fatty acid methyl ester (FAME) after extraction with a range of solvents. FP treatment increased the FAME-to-crude-lipid ratio for all solvents, which means that the extraction of non-lipid materials was minimized, while the FAME profile itself was unchanged compared to the control. FP treatment also made it possible to use only a small proportion of chloroform and methanol, along with isopropanol, to obtain equivalent yields of lipid and FAME as with 100% chloroform plus methanol.

  10. Pulsed electric field processing preserves the antiproliferative activity of the milk fat globule membrane on colon carcinoma cells.

    Science.gov (United States)

    Xu, S; Walkling-Ribeiro, M; Griffiths, M W; Corredig, M

    2015-05-01

    The present work evaluated the effect of processing on the antiproliferative activities of milk fat globule membrane (MFGM) extracts. The antiproliferative activity on human adenocarcinoma HT-29 cells of untreated MFGM extracts were compared with those extracted from pasteurized cream, thermally treated cream, or cream subjected to pulsed electrical field (PEF) processing. The PEF with a 37 kV/cm field strength applied for 1,705μs at 50 and 65°C was applied to untreated cream collected from a local dairy. Heating at 50 or 65°C for 3min (the passage time in the PEF chamber) was also tested to evaluate the heating effect during PEF treatments. The MFGM extracted from pasteurized cream did not show an antiproliferative activity. On the other hand, isolates from PEF-treated cream showed activity similar to that of untreated samples. It was also shown that PEF induced interactions between β-lactoglobulin and MFGM proteins at 65°C, whereas the phospholipid composition remained unaltered. This work demonstrates the potential of PEF not only a means to produce a microbiologically safe product, but also as a process preserving the biofunctionality of the MFGM.

  11. Study and Identification of Microflora for the Preservation of Orange Juice using Pulsed Electric Field (PEF) Processing

    Science.gov (United States)

    Ghanshyam, C.; Kaur, Manpreet; Singh, Harjodh; Kapur, Pawan

    2011-12-01

    Pulsed Electric Field (PEF) is an emerging nonthermal food processing technology being effective in microbial inactivation without impairing the food quality. This paper demonstrates characterization of microbiota present in liquid food so that effective range of PEF can be set accordingly thus depicting the type of microorganism present, its morphology and its cell wall chemistry. The investigated microorganisms included E.coli, Staphylococcus aureus and Listeria monocytogenes, isolated from spoiled orange juice samples. These were characterized through a series of biochemical tests following microscopic (SEM) & spectroscopic (FTIR) characterization. The results were confirmed with respect to Standard MTCC (Microbial Type Culture Collection) strains (MTCC 614, MTCC 96, and MTCC 657). In comparison to Gram negative bacteria, the Gram positive bacteria are more resistant towards PEF. Larger microbial cells require less intense field strength to undergo an equivalent inactivation as compared to smaller cells. Cells in the exponential growth phase are more sensitive than the cells in lag or stationary phase, so it is necessary to identify the predominant bacteria in particular liquid foods.

  12. Effect of pulsed electric field treatment on enzyme kinetics and thermostability of endogenous ascorbic acid oxidase in carrots (Daucus carota cv. Nantes).

    Science.gov (United States)

    Leong, Sze Ying; Oey, Indrawati

    2014-03-01

    The objective of this research was to study the enzyme kinetics and thermostability of endogenous ascorbic acid oxidase (AAO) in carrot purée (Daucus carota cv. Nantes) after being treated with pulsed electric field (PEF) processing. Various PEF treatments using electric field strength between 0.2 and 1.2kV/cm and pulsed electrical energy between 1 and 520kJ/kg were conducted. The enzyme kinetics and the kinetics of AAO thermal inactivation (55-70°C) were described using Michaelis-Menten model and first order reaction model, respectively. Overall, the estimated Vmax and KM values were situated in the same order of magnitude as the untreated carrot purée after being exposed to pulsed electrical energy between 1 and 400kJ/kg, but slightly changed at pulsed electrical energy above 500kJ/kg. However, AAO presented different thermostability depending on the electric field strength applied. After PEF treatment at the electric field strength between 0.2 and 0.5kV/cm, AAO became thermolabile (i.e. increase in inactivation rate (k value) at reference temperature) but the temperature dependence of k value (Ea value) for AAO inactivation in carrot purée decreased, indicating that the changes in k values were less temperature dependent. It is obvious that PEF treatment affects the temperature stability of endogenous AAO. The changes in enzyme kinetics and thermostability of AAO in carrot purée could be related to the resulting carrot purée composition, alteration in intracellular environment and the effective concentration of AAO released after being subjected to PEF treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Characteristics of colloidal aluminum nanoparticles prepared by nanosecond pulsed laser ablation in deionized water in presence of parallel external electric field

    Science.gov (United States)

    Mahdieh, Mohammad Hossein; Mozaffari, Hossein

    2017-10-01

    In this paper, we investigate experimentally the effect of electric field on the size, optical properties and crystal structure of colloidal nanoparticles (NPs) of aluminum prepared by nanosecond Pulsed Laser Ablation (PLA) in deionized water. The experiments were conducted for two different conditions, with and without the electric field parallel to the laser beam path and the results were compared. To study the influence of electric field, two polished parallel aluminum metals plates perpendicular to laser beam path were used as the electrodes. The NPs were synthesized for target in negative, positive and neutral polarities. The colloidal nanoparticles were characterized using the scanning electron microscopy (SEM), UV-vis absorption spectroscopy and X-ray Diffraction (XRD). The results indicate that initial charge on the target has strong effect on the size properties and concentration of the synthesized nanoparticles. The XRD patterns show that the structure of produced NPs with and without presence of electric field is Boehmite (AlOOH).

  14. Nanosecond pulsed electric fields (nsPEFs) low cost generator design using power MOSFET and Cockcroft-Walton multiplier circuit as high voltage DC source

    Science.gov (United States)

    Sulaeman, M. Y.; Widita, R.

    2014-09-01

    Purpose: Non-ionizing radiation therapy for cancer using pulsed electric field with high intensity field has become an interesting field new research topic. A new method using nanosecond pulsed electric fields (nsPEFs) offers a novel means to treat cancer. Not like the conventional electroporation, nsPEFs able to create nanopores in all membranes of the cell, including membrane in cell organelles, like mitochondria and nucleus. NsPEFs will promote cell death in several cell types, including cancer cell by apoptosis mechanism. NsPEFs will use pulse with intensity of electric field higher than conventional electroporation, between 20-100 kV/cm and with shorter duration of pulse than conventional electroporation. NsPEFs requires a generator to produce high voltage pulse and to achieve high intensity electric field with proper pulse width. However, manufacturing cost for creating generator that generates a high voltage with short duration for nsPEFs purposes is highly expensive. Hence, the aim of this research is to obtain the low cost generator design that is able to produce a high voltage pulse with nanosecond width and will be used for nsPEFs purposes. Method: Cockcroft-Walton multiplier circuit will boost the input of 220 volt AC into high voltage DC around 1500 volt and it will be combined by a series of power MOSFET as a fast switch to obtain a high voltage with nanosecond pulse width. The motivation using Cockcroft-Walton multiplier is to acquire a low-cost high voltage DC generator; it will use capacitors and diodes arranged like a step. Power MOSFET connected in series is used as voltage divider to share the high voltage in order not to damage them. Results: This design is expected to acquire a low-cost generator that can achieve the high voltage pulse in amount of -1.5 kV with falltime 3 ns and risetime 15 ns into a 50Ω load that will be used for nsPEFs purposes. Further detailed on the circuit design will be explained at presentation.

  15. Nanosecond pulsed electric fields (nsPEFs) low cost generator design using power MOSFET and Cockcroft-Walton multiplier circuit as high voltage DC source

    Energy Technology Data Exchange (ETDEWEB)

    Sulaeman, M. Y.; Widita, R. [Department of Physics, Nuclear Physics and Biophysics Research Division, Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Bandung (Indonesia)

    2014-09-30

    Purpose: Non-ionizing radiation therapy for cancer using pulsed electric field with high intensity field has become an interesting field new research topic. A new method using nanosecond pulsed electric fields (nsPEFs) offers a novel means to treat cancer. Not like the conventional electroporation, nsPEFs able to create nanopores in all membranes of the cell, including membrane in cell organelles, like mitochondria and nucleus. NsPEFs will promote cell death in several cell types, including cancer cell by apoptosis mechanism. NsPEFs will use pulse with intensity of electric field higher than conventional electroporation, between 20–100 kV/cm and with shorter duration of pulse than conventional electroporation. NsPEFs requires a generator to produce high voltage pulse and to achieve high intensity electric field with proper pulse width. However, manufacturing cost for creating generator that generates a high voltage with short duration for nsPEFs purposes is highly expensive. Hence, the aim of this research is to obtain the low cost generator design that is able to produce a high voltage pulse with nanosecond width and will be used for nsPEFs purposes. Method: Cockcroft-Walton multiplier circuit will boost the input of 220 volt AC into high voltage DC around 1500 volt and it will be combined by a series of power MOSFET as a fast switch to obtain a high voltage with nanosecond pulse width. The motivation using Cockcroft-Walton multiplier is to acquire a low-cost high voltage DC generator; it will use capacitors and diodes arranged like a step. Power MOSFET connected in series is used as voltage divider to share the high voltage in order not to damage them. Results: This design is expected to acquire a low-cost generator that can achieve the high voltage pulse in amount of −1.5 kV with falltime 3 ns and risetime 15 ns into a 50Ω load that will be used for nsPEFs purposes. Further detailed on the circuit design will be explained at presentation.

  16. Nanosecond Pulsed Electric Fields Enhance the Anti-tumour Effects of the mTOR Inhibitor Everolimus against Melanoma

    Science.gov (United States)

    Dai, Jie; Wu, Shan; Kong, Yan; Chi, Zhihong; Si, Lu; Sheng, Xinan; Cui, Chuanliang; Fang, Jing; Zhang, Jue; Guo, Jun

    2017-01-01

    The PI3K/mTOR/AKT pathway is activated in most melanomas, but mTOR inhibitors used singly have limited activity against advanced melanomas. The application of nanosecond pulsed electric fields (nsPEFs) is a promising cancer therapy approach. In this study, we evaluated the synergistic anti-tumour efficacy of the mTOR inhibitor everolimus in conjunction with nsPEFs against melanoma. The combined treatment of nsPEFs and everolimus gradually decreased cell growth concurrent with nsPEF intensity. nsPEFs alone or combined with everolimus could promote melanoma cell apoptosis, accompanied with a loss in cellular mitochondrial membrane potential and an increase in Ca2+ levels. In vivo experiments showed that a combination of the mTOR inhibitor everolimus and nsPEFs improved the inhibitory effect, and all skin lesions caused by nsPEFs healed in 1 week without any observed adverse effect. Combination treatment induced caspase-dependent apoptosis through the upregulation of the pro-apoptotic factor Bax and downregulation of the anti-apoptotic factor Bcl-2. Everolimus and nsPEFs synergistically inhibited angiogenesis by decreasing the expression of vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR), and CD34. Our findings indicate that nsPEFs in combination with an mTOR inhibitor can be used as a potential treatment approach for advanced melanoma. PMID:28054548

  17. Effect of repeated pulsed electric field treatment on the quality of hot-boned beef loins and topsides.

    Science.gov (United States)

    Bekhit, Alaa El-Din A; Suwandy, Via; Carne, Alan; van de Ven, Remy; Hopkins, David L

    2016-01-01

    The effects of repeated (1×, 2×, 3×) pulsed electric field (PEF) treatment (10 kV, 90 Hz, 20 μs) on the quality of beef loins and topsides were evaluated, including the tenderness, purge loss, cooking loss, myofibrillar protein profile and post-mortem proteolysis. Both muscle types were obtained from each of 12 steers and were processed within 6h. After PEF treatment samples of both muscle types were subjected to 3, 7, 14 and 21 days ageing. The 1× and 2× PEF treatments had no effect on the tenderisation of hot-boned beef Musculus longissimus lumborum muscle for all ageing treatment times, while the 3× treatment reduced the tenderness. The opposite effect was observed in hot-boned beef Musculus semimembranosus muscles where the 3× treatment produced meat with lowest shear force at 3 days post-treatment time, but this beneficial effect disappeared with longer ageing times. An increase in proteolysis of troponin T was seen to the largest extent with 1× PEF treatment and decreased with every extra application of treatment.

  18. Investigation of the metabolic consequences of impregnating spinach leaves with trehalose and applying a pulsed electric field.

    Science.gov (United States)

    Dymek, Katarzyna; Panarese, Valentina; Herremans, Els; Cantre, Dennis; Schoo, Rick; Toraño, Javier Sastre; Schluepmann, Henriette; Wadso, Lars; Verboven, Pieter; Nicolai, Bart M; Dejmek, Petr; Gómez Galindo, Federico

    2016-12-01

    The impregnation of leafy vegetables with cryoprotectants using a combination of vacuum impregnation (VI) and pulsed electric fields (PEF) has been proposed by our research group as a method of improving their freezing tolerance and consequently their general quality after thawing. In this study, we have investigated the metabolic consequences of the combination of these unit operations on spinach. The vacuum impregnated spinach leaves showed a drastic decrease in the porosity of the extracellular space. However, at maximum weight gain, randomly located air pockets remained, which may account for oxygen-consuming pathways in the cells being active after VI. The metabolic activity of the impregnated leaves showed a drastic increase that was further enhanced by the application of PEF to the impregnated tissue. Impregnating the leaves with trehalose by VI led to a significant accumulation of trehalose-6-phosphate (T6P), however, this was not further enhanced by PEF. It is suggested that the accumulation of T6P in the leaves may increase metabolic activity, and increase tissue resistance to abiotic stress.

  19. Electron-ion-ion coincidence experiments for photofragmentation of polyatomic molecules using pulsed electric fields: Treatment of random coincidences

    Energy Technology Data Exchange (ETDEWEB)

    Pruemper, G. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980 8577 (Japan)]. E-mail: pruemper@tagen.tohoku.ac.jp; Ueda, K. [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980 8577 (Japan)

    2007-05-01

    In molecular photofragmentation processes by soft X-rays, a number of ionic fragments can be produced, each having a different abundance and correlation with the kinetic energy of the emitted electron. For investigating these fragmentation processes, electron-ion and electron-ion-ion coincidence experiments, in which the kinetic energy of electrons are analyzed using an electrostatic analyzer while the mass of the ions is analyzed using a pulsed electric field, are very powerful. For such measurements, however, the contribution of random coincidences is substantial and affects the data in a non-trivial way. Simple intuitive subtraction methods cannot be applied. In the present paper, we describe these electron-ion and electron-ion-ion coincidence experiments together with a subtraction method for the contribution from random coincidences. We provide a comprehensive set of equations for the data treatment, including equations for the calculation of error-bars. We demonstrate the method by applying it to the fragmentation of free CF{sub 3}SF{sub 5} molecules.

  20. Electropriming of wheatgrass seeds using pulsed electric fields enhances antioxidant metabolism and the bioprotective capacity of wheatgrass shoots

    Science.gov (United States)

    Leong, Sze Ying; Burritt, David John; Oey, Indrawati

    2016-01-01

    The influence of pulsed electric field (PEF) (0.5–2 kV/cm) treatment of wheatgrass (Triticum aestivum L.) seeds, with different water contents, on antioxidant metabolism in the resultant seedlings was investigated. Imbibing seeds to a water content of 45% or greater prior to PEF treatment increased the glutathione level and activities of superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and ascorbate peroxidase in the resultant seedlings, compared to untreated controls. Pre-culture of human intestinal Caco-2 cells with simulated gastrointestinal digests of electrostimulated seedlings enhanced the ability of Caco-2 cells to cope with H2O2-induced oxidative damage, determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release assays. The Caco-2 cell MTT and LDH assays correlated better with the increases in seedling glutathione content and antioxidant enzyme activities compared to the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) total antioxidant capacity assay, an assay commonly used to determine the ability of plant extracts to protect cells from oxidative damage. These results demonstrate for the first time that PEF treatment of imbibed seeds can stimulate changes in metabolism in the resultant seedlings, increasing the bioprotective potential of their shoots/sprouts and hence value as functional foods. PMID:27147445

  1. Effects of ultraviolet irradiation, pulsed electric field, hot water and ethanol vapours treatment on functional properties of mung bean sprouts.

    Science.gov (United States)

    Goyal, Ankit; Siddiqui, Saleem; Upadhyay, Neelam; Soni, Jyoti

    2014-04-01

    The present investigation was conducted with the objective to study the effects of various treatments and storage conditions on ascorbic acid, total phenols, antioxidant activity and polyphenol oxidase activity of mung bean sprouts. The sprouts subjected to various treatments viz., pulsed electric field (PEF) (10,000 V for 10 s), hot water dip (HWD) (50 °C for 2 min), ethanol vapours (1 h) and UV-Irradiation (10 kJm(-2) in laminar flow chamber for 1 h); and then stored at room (25 ± 1 °C) and low (7 ± 1 °C) temperature conditions. The sprouts were analyzed regularly at 24 h interval till end of shelf life. Different treatments given to sprouts resulted in differential effect on various parameters. The ascorbic acid, total phenols and antioxidant activity were highest in ethanol vapours treated sprouts. There was a general decrease in polyphenol oxidase activity by various treatments. During storage ascorbic acid, total phenols and antioxidant activity of sprouts first increased and then decreased significantly, however, for polyphenol oxidase activity a progressive increase with increase in storage period was observed. The trends were similar at room and low temperature storage conditions. Thus, it can be concluded that the ethanol vapours significantly improved the ascorbic acid content, total phenols and antioxidant activity of mung bean sprouts, both at room as well as low temperature conditions of storage.

  2. Research on the preparation of antioxidant peptides derived from egg white with assisting of high-intensity pulsed electric field.

    Science.gov (United States)

    Lin, Songyi; Jin, Yan; Liu, Mingyuan; Yang, Yi; Zhang, Meishuo; Guo, Yang; Jones, Gregory; Liu, Jingbo; Yin, Yongguang

    2013-08-15

    Egg white protein powder, one of the main egg products, was hydrolysed by Alcalase, Trypsin, and Pepsin respectively to prepare antioxidant peptides. All hydrolysates were assayed by determination of reducing power (RP) ability. Three kinds of hydrolysates were prepared under optimal enzymatic parameters that were obtained from the preliminary one-factor-at-a-time (OFAT) and response surface methodology (RSM) experiments. The results showed that the Alcalase hydrolysates exerted the best RP ability. Thereafter, the Alcalase hydrolysates were sequentially fractionated by ultra filtration membranes in cut-off molecular weight (MW) of 30, 10, and 1 kDa, and tested their antioxidant activities in terms of RP ability, DPPH radical scavenging ability, ABTS radical scavenging ability, and FRAP assay. Effects of high intensity pulsed electric field treatment were further investigated on antioxidant peptides to improve their activities. The results showed that Alcalase hydrolysates possessed the strongest antioxidant ability compared with the other two hydrolysates, particularly for the Fraction-3 with MW <1 kDa. After PEF treatment, this fraction showed a significant improvement of RP ability within 5 h (P<0.05).

  3. Consumer perception of the use of high-pressure processing and pulsed electric field technologies in food production.

    Science.gov (United States)

    Nielsen, Henriette Boel; Sonne, Anne-Mette; Grunert, Klaus G; Banati, Diana; Pollák-Tóth, Annamária; Lakner, Zoltán; Olsen, Nina Veflen; Zontar, Tanja Pajk; Peterman, Marjana

    2009-02-01

    The success of new food processing technologies is highly dependent on consumers' acceptance. The purpose of this paper is to study consumers' perceptions of two new processing technologies and food products produced by means of these novel technologies. To accomplish this, a qualitative study on consumer attitudes towards high-pressure processing (HPP) and pulsed electric field (PEF) processing of food was carried out. In all 97 adults between 20 and 71 years of age participated in 12 focus groups conducted in Slovenia, Hungary, Serbia, Slovakia, Norway and Denmark using a common guideline. Participants were introduced to the HPP and PEF technologies and then to the effect of the two new technologies on two specific product categories: juice and baby food. The transcribed data was content analysed and the coded data was transformed into diagrams using UCINET 5 and NETDRAW. The results show that consumers perceived the main advantages of HPP and PEF products to be the products' naturalness, improved taste and their high nutritional value, whereas the main disadvantage was the lack of information about the PEF and HPP products. The results of the participants' evaluation of the PEF and HPP processes showed that environmental friendliness and the more natural products were seen as the main advantages, while they were concerned about body and health, the higher price of the products, the lack of information about the technologies and a general scepticism. The study also shows that North European participants were a bit more sceptical towards PEF and HPP products than the East European participants.

  4. Olive oil pilot-production assisted by pulsed electric field: impact on extraction yield, chemical parameters and sensory properties.

    Science.gov (United States)

    Puértolas, Eduardo; Martínez de Marañón, Iñigo

    2015-01-15

    The impact of the use of pulsed electric field (PEF) technology on Arroniz olive oil production in terms of extraction yield and chemical and sensory quality has been studied at pilot scale in an industrial oil mill. The application of a PEF treatment (2 kV/cm; 11.25 kJ/kg) to the olive paste significantly increased the extraction yield by 13.3%, with respect to a control. Furthermore, olive oil obtained by PEF showed total phenolic content, total phytosterols and total tocopherols significantly higher than control (11.5%, 9.9% and 15.0%, respectively). The use of PEF had no negative effects on general chemical and sensory characteristics of the olive oil, maintaining the highest quality according to EU legal standards (EVOO; extra virgin olive oil). Therefore, PEF could be an appropriate technology to improve olive oil yield and produce EVOO enriched in human-health-related compounds, such as polyphenols, phytosterols and tocopherols. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Nanosecond Pulsed Electric Fields Enhance the Anti-tumour Effects of the mTOR Inhibitor Everolimus against Melanoma

    Science.gov (United States)

    Dai, Jie; Wu, Shan; Kong, Yan; Chi, Zhihong; Si, Lu; Sheng, Xinan; Cui, Chuanliang; Fang, Jing; Zhang, Jue; Guo, Jun

    2017-01-01

    The PI3K/mTOR/AKT pathway is activated in most melanomas, but mTOR inhibitors used singly have limited activity against advanced melanomas. The application of nanosecond pulsed electric fields (nsPEFs) is a promising cancer therapy approach. In this study, we evaluated the synergistic anti-tumour efficacy of the mTOR inhibitor everolimus in conjunction with nsPEFs against melanoma. The combined treatment of nsPEFs and everolimus gradually decreased cell growth concurrent with nsPEF intensity. nsPEFs alone or combined with everolimus could promote melanoma cell apoptosis, accompanied with a loss in cellular mitochondrial membrane potential and an increase in Ca2+ levels. In vivo experiments showed that a combination of the mTOR inhibitor everolimus and nsPEFs improved the inhibitory effect, and all skin lesions caused by nsPEFs healed in 1 week without any observed adverse effect. Combination treatment induced caspase-dependent apoptosis through the upregulation of the pro-apoptotic factor Bax and downregulation of the anti-apoptotic factor Bcl-2. Everolimus and nsPEFs synergistically inhibited angiogenesis by decreasing the expression of vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR), and CD34. Our findings indicate that nsPEFs in combination with an mTOR inhibitor can be used as a potential treatment approach for advanced melanoma.

  6. Effects of nanosecond pulsed electrical fields (nsPEFs) on the cell cycle of CHO and Jurkat cells

    Science.gov (United States)

    Mahlke, Megan A.; Navara, Christopher; Ibey, Bennett L.

    2014-03-01

    Exposure to nano-second pulsed electrical fields (nsPEFs) can cause poration of external and internal cell membranes, DNA damage, and disassociation of cytoskeletal components, all of which are capable of disrupting a cell's ability to replicate. Variations between cell lines in membrane and cytoskeletal structure as well as in survival of nsPEF exposure should correspond to unique line-dependent cell cycle effects. Additionally, phase of cell cycle during exposure may be linked to differential sensitivities to nsPEFs across cell lines, as DNA structure, membrane elasticity, and cytoskeletal structure change dramatically during the cell cycle. Populations of Jurkat and Chinese Hamster Ovary (CHO) cells were examined post-exposure (10 ns pulse trains at 150kV/cm) by analysis of DNA content via propidium iodide staining and flow cytometric analysis at various time points (1, 6, and 12h post-exposure) to determine population distribution in cell cycle phases. Additionally, CHO and Jurkat cells were synchronized in G1/S and G2/M phases, pulsed, and analyzed to evaluate role of cell cycle phase in survival of nsPEFs. CHO populations recovered similarly to sham populations postnsPEF exposure and did not exhibit a phase-specific change in response. Jurkat cells exhibited considerable apoptosis/necrosis in response to nsPEF exposure and were unable to recover and proliferate in a manner similar to sham exposed cells. Additionally, Jurkat cells appear to be more sensitive to nsPEFs in G2/M phases than in G1/S phases. Recovery of CHO populations suggests that nsPEFs do not inhibit proliferation in CHO cells; however, inhibition of Jurkat cells post-nsPEF exposure coupled with preferential cell death in G2/M phases suggest that cell cycle phase during exposure may be an important factor in determining nsPEF toxicity in certain cell lines. Interestingly, CHO cells have a more robust and rigid cytoskeleton than Jurkat cells which is thought to contribute to their ability to

  7. A Comparative Study on the Effects of Millisecond- and Microsecond-Pulsed Electric Field Treatments on the Permeabilization and Extraction of Pigments from Chlorella vulgaris.

    Science.gov (United States)

    Luengo, Elisa; Martínez, Juan Manuel; Coustets, Mathilde; Álvarez, Ignacio; Teissié, Justin; Rols, Marie-Pierre; Raso, Javier

    2015-10-01

    The interdependencies of the two main processing parameters affecting "electroporation" (electric field strength and pulse duration) while using pulse duration in the range of milliseconds and microseconds on the permeabilization, inactivation, and extraction of pigments from Chlorella vulgaris was compared. While irreversible "electroporation" was observed above 4 kV/cm in the millisecond range, electric field strengths of ≥10 kV/cm were required in the microseconds range. However, to cause the electroporation of most of the 90 % of the population of C. vulgaris in the millisecond (5 kV/cm, 20 pulses) or microsecond (15 kV/cm, 25 pulses) range, the specific energy that was delivered was lower for microsecond treatments (16.87 kJ/L) than in millisecond treatments (150 kJ/L). In terms of the specific energy required to cause microalgae inactivation, treatments in the microsecond range also resulted in greater energy efficiency. The comparison of extraction yields in the range of milliseconds (5 kV, 20 ms) and microseconds (20, 25 pulses) under the conditions in which the maximum extraction was observed revealed that the improvement in the carotenoid extraction was similar and chlorophyll a and b extraction was slightly higher for treatments in the microsecond range. The specific energy that was required for the treatment in the millisecond range (150 kJ/L) was much higher than those required in the microsecond range (30 kJ/L). The comparison of the efficacy of both types of pulses on the extraction enhancement just after the treatment and after a post-pulse incubation period seemed to indicate that PEF in the millisecond range created irreversible alterations while, in the microsecond range, the defects were a dynamic structure along the post-pulse time that caused a subsequent increment in the extraction yield.

  8. Electric fields and electrical insulation

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    2002-01-01

    The adoption of a field-theoretical approach to problems arising in the framework of electrical insulation is discussed with reference to six main topics, which have been addressed over the last 30 years. These include uniform field electrodes, Green's differential equation, electrode surface......, it is amply demonstrated that such an approach can lead to significant progress in many areas of electrical insulation....

  9. Change in Color and Volatile Composition of Skim Milk Processed with Pulsed Electric Field and Microfiltration Treatments or Heat Pasteurization

    Directory of Open Access Journals (Sweden)

    Anupam Chugh

    2014-04-01

    Full Text Available Non-thermal processing methods, such as pulsed electric field (PEF and tangential-flow microfiltration (TFMF, are emerging processing technologies that can minimize the deleterious effects of high temperature short time (HTST pasteurization on quality attributes of skim milk. The present study investigates the impact of PEF and TFMF, alone or in combination, on color and volatile compounds in skim milk. PEF was applied at 28 or 40 kV/cm for 1122 to 2805 µs, while microfiltration (MF was conducted using membranes with three pore sizes (lab-scale 0.65 and 1.2 µm TFMF, and pilot-scale 1.4 µm MF. HTST control treatments were applied at 75 or 95 °C for 20 and 45 s, respectively. Noticeable color changes were observed with the 0.65 µm TFMF treatment. No significant color changes were observed in PEF-treated, 1.2 µm TFMF-treated, HTST-treated, and 1.4 µm MF-treated skim milk (p ≥ 0.05 but the total color difference indicated better color retention with non-thermal preservation. The latter did not affect raw skim milk volatiles significantly after single or combined processing (p ≥ 0.05, but HTST caused considerable changes in their composition, including ketones, free fatty acids, hydrocarbons, and sulfur compounds (p < 0.05. The findings indicate that for the particular thermal and non-thermal treatments selected for this study, better retention of skim milk color and flavor components were obtained for the non-thermal treatments.

  10. Cellular regulation of extension and retraction of pseudopod-like blebs produced by nanosecond pulsed electric field (nsPEF).

    Science.gov (United States)

    Rassokhin, Mikhail A; Pakhomov, Andrei G

    2014-07-01

    Recently we described a new phenomenon of anodotropic pseudopod-like blebbing in U937 cells exposed to nanosecond pulsed electric field (nsPEF). In Ca(2+)-free buffer such exposure initiates formation of pseudopod-like blebs (PLBs), protrusive cylindrical cell extensions that are distinct from apoptotic and necrotic blebs. PLBs nucleate predominantly on anode-facing cell pole and extend toward anode during nsPEF exposure. Bleb extension depends on actin polymerization and availability of actin monomers. Inhibition of intracellular Ca(2+), cell contractility, and RhoA produced no effect on PLB initiation. Meanwhile, inhibition of WASP by wiskostatin causes dose-dependent suppression of PLB growth. Soon after the end of nsPEF exposure PLBs lose directionality of growth and then retract. Microtubule toxins nocodazole and paclitaxel did not show immediate effect on PLBs; however, nocodazole increased mobility of intracellular components during PLB extension and retraction. Retraction of PLBs is produced by myosin activation and the corresponding increase in PLB cortex contractility. Inhibition of myosin by blebbistatin reduces retraction while inhibition of RhoA-ROCK pathway by Y-27632 completely prevents retraction. Contraction of PLBs can produce cell translocation resembling active cell movement. Overall, the formation, properties, and life cycle of PLBs share common features with protrusions associated with ameboid cell migration. PLB life cycle may be controlled through activation of WASP by its upstream effectors such as Cdc42 and PIP2, and main ROCK activator-RhoA. Parallels between pseudopod-like blebbing and motility blebbing may provide new insights into their underlying mechanisms.

  11. Platelet-rich plasma stimulated by pulse electric fields: Platelet activation, procoagulant markers, growth factor release and cell proliferation.

    Science.gov (United States)

    Frelinger, A L; Torres, A S; Caiafa, A; Morton, C A; Berny-Lang, M A; Gerrits, A J; Carmichael, S L; Neculaes, V B; Michelson, A D

    2016-01-01

    Therapeutic use of activated platelet-rich plasma (PRP) has been explored for wound healing, hemostasis and antimicrobial wound applications. Pulse electric field (PEF) stimulation may provide more consistent platelet activation and avoid complications associated with the addition of bovine thrombin, the current state of the art ex vivo activator of therapeutic PRP. The aim of this study was to compare the ability of PEF, bovine thrombin and thrombin receptor activating peptide (TRAP) to activate human PRP, release growth factors and induce cell proliferation in vitro. Human PRP was prepared in the Harvest SmartPreP2 System and treated with vehicle, PEF, bovine thrombin, TRAP or Triton X-100. Platelet activation and procoagulant markers and microparticle generation were measured by flow cytometry. Released growth factors were measured by ELISA. The releasates were tested for their ability to stimulate proliferation of human epithelial cells in culture. PEF produced more platelet-derived microparticles, P-selectin-positive particles and procoagulant annexin V-positive particles than bovine thrombin or TRAP. These differences were associated with higher levels of released epidermal growth factor after PEF than after bovine thrombin or TRAP but similar levels of platelet-derived, vascular-endothelial, and basic fibroblast growth factors, and platelet factor 4. Supernatant from PEF-treated platelets significantly increased cell proliferation compared to plasma. In conclusion, PEF treatment of fresh PRP results in generation of microparticles, exposure of prothrombotic platelet surfaces, differential release of growth factors compared to bovine thrombin and TRAP and significant cell proliferation. These results, together with PEF's inherent advantages, suggest that PEF may be a superior alternative to bovine thrombin activation of PRP for therapeutic applications.

  12. 高强脉冲电场与臭氧联用降解壳聚糖%Degradation of chitosan by high voltage pulsed electric field and ozone

    Institute of Scientific and Technical Information of China (English)

    罗文波; 唐超; 曾新安; 于淑娟

    2013-01-01

    The vigorous oxidation ability of ozone and the high energy input of pulsed electric field were utilized to degrade the macromolecular chitosan to oligochitosan. The degradation rate was up to 98. 5% after the combined treatment of high voltage pulsed electric field and ozone for 30 minutes in acetic acid homogeneous phase. Three experiment schemes of individual and combined treatments of high voltage pulsed electric field and ozone were designed the results showed that the efficiency of combined treatment was higher than that of single treatments, so the combination of high voltage pulsed electric field and ozone had high synergistic effect. By infrared spectrum analysis, the structure of degraded chitosan was not changed compared to the initial chitosan.%利用臭氧的强氧化性和电场的高能量降解大分子壳聚糖为壳寡糖.在乙酸均相体系中,高强脉冲电场与臭氧联用处理壳聚糖30min时,壳聚糖的降解率达到98.5%.设计了脉冲电场、臭氧单独处理和电场与臭氧联用处理3种实验方案,结果表明:电场与臭氧联用的处理效率要高于分别处理效率,电场与臭氧联用具有协同作用.经红外光谱分析,降解产物与原料壳聚糖结构基本一致.

  13. The effect of pulsed electric fields on the electrotactic migration of human neural progenitor cells through the involvement of intracellular calcium signaling.

    Science.gov (United States)

    Hayashi, Hisamitsu; Edin, Fredrik; Li, Hao; Liu, Wei; Rask-Andersen, Helge

    2016-12-01

    Endogenous electric fields (EFs) are required for the physiological control of the central nervous system development. Application of the direct current EFs to neural stem cells has been studied for the possibility of stem cell transplantation as one of the therapies for brain injury. EFs generated within the nervous system are often associated with action potentials and synaptic activity, apparently resulting in a pulsed current in nature. The aim of this study is to investigate the effect of pulsed EF, which can reduce the cytotoxicity, on the migration of human neural progenitor cells (hNPCs). We applied the mono-directional pulsed EF with a strength of 250mV/mm to hNPCs for 6h. The migration distance of the hNPCs exposed to pulsed EF was significantly greater compared with the control not exposed to the EF. Pulsed EFs, however, had less of an effect on the migration of the differentiated hNPCs. There was no significant change in the survival of hNPCs after exposure to the pulsed EF. To investigate the role of Ca(2+) signaling in electrotactic migration of hNPCs, pharmacological inhibition of Ca(2+) channels in the EF-exposed cells revealed that the electrotactic migration of hNPCs exposed to Ca(2+) channel blockers was significantly lower compared to the control group. The findings suggest that the pulsed EF induced migration of hNPCs is partly influenced by intracellular Ca(2+) signaling.

  14. Influence of a Weak Field of Pulsed DC Electricity on the Behavior and Incidence of Injury in Adult Steelhead and Pacific Lamprey, Final Report.

    Energy Technology Data Exchange (ETDEWEB)

    Mesa, Matthew

    2009-02-13

    electrofishing operations typically use high voltage and amperage settings and a variety of waveforms, pulse widths (PW), and pulse frequencies (PF), depending on conditions and target species. For example, when backpack electrofishing for trout in a small stream, one might use settings such as 500 V pulsed DC, a PW of 1 ms, and a PF of 60 Hz. In contrast, the electrical barrier proposed by SRI will produce electrical conditions significantly lower than those used in electrofishing, particularly for PW and PF (e.g., PW ranging from 300-1,000 {micro}s and PF from 2-3 Hz). Further, voltage gradients (in V/cm) are predicted to be lower in the electric barrier than those produced during typical electrofishing. Although the relatively weak, pulsed DC electric fields to be produced by the barrier may be effective at deterring pinnipeds, little, if anything, is known about the effects of such low intensity electrical fields on fish behavior. For this research, we evaluated the effects of weak, pulsed DC electric currents on the behavior of adult steelhead and Pacific lamprey and the incidence of injury in steelhead only. In a series of laboratory experiments, we: (1) documented the rate of passage of fish over miniature, prototype electric barriers when they were on and off; (2) determined some electric thresholds beyond which fish would not pass over the barrier; and (3) assessed the incidence and severity of injury in steelhead exposed to relatively severe electrical conditions. The results of this study should be useful for making decisions about whether to install electrical barriers in the lower Columbia River, or elsewhere, to reduce predation on upstream migrating salmonids and other fishes by marine pinnipeds.

  15. Heredity of Aluminum Melt by Electric Pulse Modification (Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    QI Jin-gang; WANG Jian-zhong; DU Hui-ling; CAO Li-yun

    2007-01-01

    Heredity of high pure aluminum melts under different pulse electric field was investigated by means of repetitious remelt experiment. The results indicate that the genetic coefficient by measurement of grain size of cast structure has a close relation with pulse voltage. Moreover, the hereditary law accords with the function of In=1+e-αn+β. The stability of genetic carrier (cluster) comprises in the competition between repetitious cooling and heating impulse and the effect of electric pulse modification.

  16. Electric Field Imaging Project

    Science.gov (United States)

    Wilcutt, Terrence; Hughitt, Brian; Burke, Eric; Generazio, Edward

    2016-01-01

    NDE historically has focused technology development in propagating wave phenomena with little attention to the field of electrostatics and emanating electric fields. This work is intended to bring electrostatic imaging to the forefront of new inspection technologies, and new technologies in general. The specific goals are to specify the electric potential and electric field including the electric field spatial components emanating from, to, and throughout volumes containing objects or in free space.

  17. Electric field control of Skyrmions in magnetic nanodisks

    Science.gov (United States)

    Nakatani, Y.; Hayashi, M.; Kanai, S.; Fukami, S.; Ohno, H.

    2016-04-01

    The control of magnetic Skyrmions confined in a nanometer scale disk using electric field pulses is studied by micromagnetic simulation. A stable Skyrmion can be created and annihilated by an electric field pulse depending on the polarity of the electric field. Moreover, the core direction of the Skyrmion can be switched using the same electric field pulses. Such creation and annihilation of Skyrmions, and its core switching do not require any magnetic field and precise control of the pulse length. This unconventional manipulation of magnetic texture using electric field pulses allows a robust way of controlling magnetic Skyrmions in nanodiscs, a path toward building ultralow power memory devices.

  18. 高压脉冲电场杀菌系统的研究进展%Development of pulsed electric field sterilization system

    Institute of Scientific and Technical Information of China (English)

    金伟; 平雪良; 吉祥; 许卫斌

    2012-01-01

    杀菌是食品加工处理过程中的一个重要工序.杀菌效果的好坏直接影响食品的安全与卫生,传统的杀菌技术会对食品的营养价值和风味产生一定的副作用.高压脉冲电场(PEF)杀菌技术因其杀菌效果好、快速、低耗、安全等优点而被广泛地用于食品杀菌中.文章介绍国内外高压脉冲电场杀菌技术对高压脉冲发生器、处理室、杀菌系统的影响,并综述对其应用的研究.%Sterilization is an important procedure in food processing. The effect of sterilization has a direct influence on food safety and healthy,The traditional sterilization technology will have a side effect on the value and flavor of food. Pulsed electric field(PEF) sterilization technology is widely used in food processing for affectivity, rap-idness, safety and low consumption. This paper summarizes the development of high voltage pulsed electric field sterilization technology both at home and aboard, including high voltage pulse generator, treatment chamber, influence of sterilization system and its application.

  19. Technological characteristics and selected bioactive compounds of Opuntia dillenii cactus fruit juice following the impact of pulsed electric field pre-treatment.

    Science.gov (United States)

    Moussa-Ayoub, Tamer E; Jaeger, Henry; Youssef, Khaled; Knorr, Dietrich; El-Samahy, Salah; Kroh, Lothar W; Rohn, Sascha

    2016-11-01

    Selected technological characteristics and bioactive compounds of juice pressed directly from the mash of whole Opuntia dillenii cactus fruits have been investigated. The impact of pulsed electric fields (PEF) for a non-thermal disintegration on the important juice characteristics has been evaluated in comparison to microwave heating and use of pectinases. Results showed that the cactus juice exhibited desirable technological characteristics. Besides, it also contained a high amount of phenolic compounds being the major contributors to the overall antioxidant activity of juice. HPLC-DAD/ESI-MS(n) measurements in the fruits' peel and pulp showed that isorhamnetin 3-O-rutinoside was determined as the single flavonol found only in the fruit's peel. Treating fruit mash with a moderate electric field strength increased juice yield and improved juice characteristics. Promisingly, the highest release of isorhamnetin 3-O-rutinoside from fruit's peel into juice was maximally achieved by PEF. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Pulsed electric field processing of different fruit juices: impact of pH and temperature on inactivation of spoilage and pathogenic micro-organisms.

    Science.gov (United States)

    Timmermans, R A H; Nierop Groot, M N; Nederhoff, A L; van Boekel, M A J S; Matser, A M; Mastwijk, H C

    2014-03-03

    Pulsed electrical field (PEF) technology can be used for the inactivation of micro-organisms and therefore for preservation of food products. It is a mild technology compared to thermal pasteurization because a lower temperature is used during processing, leading to a better retention of the quality. In this study, pathogenic and spoilage micro-organisms relevant in refrigerated fruit juices were studied to determine the impact of process parameters and juice composition on the effectiveness of the PEF process to inactivate the micro-organisms. Experiments were performed using a continuous-flow PEF system at an electrical field strength of 20 kV/cm with variable frequencies to evaluate the inactivation of Salmonella Panama, Escherichia coli, Listeria monocytogenes and Saccharomyces cerevisiae in apple, orange and watermelon juices. Kinetic data showed that under the same conditions, S. cerevisiae was the most sensitive micro-organism, followed by S. Panama and E. coli, which displayed comparable inactivation kinetics. L. monocytogenes was the most resistant micro-organism towards the treatment conditions tested. A synergistic effect between temperature and electric pulses was observed at inlet temperatures above 35 °C, hence less energy for inactivation was required at higher temperatures. Different juice matrices resulted in a different degree of inactivation, predominantly determined by pH. The survival curves were nonlinear and could satisfactorily be modeled with the Weibull model.

  1. Electric field analysis

    CERN Document Server

    Chakravorti, Sivaji

    2015-01-01

    This book prepares newcomers to dive into the realm of electric field analysis. The book details why one should perform electric field analysis and what are its practical implications. It emphasizes both the fundamentals and modern computational methods of electric machines. The book covers practical applications of the numerical methods in high voltage equipment, including transmission lines, power transformers, cables, and gas insulated systems.

  2. Development of the experimental procedure to examine the response of carbon fiber-reinforced polymer composites subjected to a high-intensity pulsed electric field and low-velocity impact.

    Science.gov (United States)

    Hart, Robert J; Zhupanska, Olesya I

    2016-01-01

    A new fully automated experimental setup has been developed to study the response of carbon fiber reinforced polymer (CFRP) composites subjected to a high-intensity pulsed electric field and low-velocity impact. The experimental setup allows for real-time measurements of the pulsed electric current, voltage, impact load, and displacements on the CFRP composite specimens. The setup includes a new custom-built current pulse generator that utilizes a bank of capacitor modules capable of producing a 20 ms current pulse with an amplitude of up to 2500 A. The setup enabled application of the pulsed current and impact load and successfully achieved coordination between the peak of the current pulse and the peak of the impact load. A series of electrical, impact, and coordinated electrical-impact characterization tests were performed on 32-ply IM7/977-3 unidirectional CFRP composites to assess their ability to withstand application of a pulsed electric current and determine the effects of the pulsed current on the impact response. Experimental results revealed that the electrical resistance of CFRP composites decreased with an increase in the electric current magnitude. It was also found that the electrified CFRP specimens withstood higher average impact loads compared to the non-electrified specimens.

  3. Development of the experimental procedure to examine the response of carbon fiber-reinforced polymer composites subjected to a high-intensity pulsed electric field and low-velocity impact

    Science.gov (United States)

    Hart, Robert J.; Zhupanska, Olesya I.

    2016-01-01

    A new fully automated experimental setup has been developed to study the response of carbon fiber reinforced polymer (CFRP) composites subjected to a high-intensity pulsed electric field and low-velocity impact. The experimental setup allows for real-time measurements of the pulsed electric current, voltage, impact load, and displacements on the CFRP composite specimens. The setup includes a new custom-built current pulse generator that utilizes a bank of capacitor modules capable of producing a 20 ms current pulse with an amplitude of up to 2500 A. The setup enabled application of the pulsed current and impact load and successfully achieved coordination between the peak of the current pulse and the peak of the impact load. A series of electrical, impact, and coordinated electrical-impact characterization tests were performed on 32-ply IM7/977-3 unidirectional CFRP composites to assess their ability to withstand application of a pulsed electric current and determine the effects of the pulsed current on the impact response. Experimental results revealed that the electrical resistance of CFRP composites decreased with an increase in the electric current magnitude. It was also found that the electrified CFRP specimens withstood higher average impact loads compared to the non-electrified specimens.

  4. 基于三场耦合的脉冲电场杀菌系统的工作过程仿真%Simulation of Pulsed Electric Field Sterilization System Working Process Based on Three Coupled Fields

    Institute of Scientific and Technical Information of China (English)

    吉祥; 平雪良; 金伟; 赵伟

    2012-01-01

    Pulsed electric field (PEF) for food sterilization is a process that pulsed voltage is applied to the food product,which is placed between or passed through two electrodes of the treatment chamber. During the process,the electric field strength and the temperature distribution in the treatment chamber are the two key factors affecting the system efficacy and food quality. This paper first developed a 3D model of the co-field treatment chamber,based on which developed a mathematical model of the three coupled fields according to the theory of the electric field,flow field and temperature field,and simulated the flow properties,temperature distribution of the liquid (Nacl solution) and electric field distribution in the treatment chamber under the conditions of pulse voltage V,pulse length r,frequency /,flow rate v and temperature T. The simulation obtained the relationship between the geometry of the co -field treatment chamber and the temperature,electric field distribution. It also provides an important basis for optimizing the treatment structure and improving the sterilization effect.%脉冲电场(Pulsed Electric Field,PEF)杀菌是将脉冲电压施加到处理室的两极,产生电场对食品物料进行杀菌的过程,在整个过程中,处理室中的电场强度与温度分布是影响系统杀菌效果以及食品质量的两个关键因素.作者在建立同场处理室的三维模型的基础上,根据电场、流场、温度场理论,建立了脉冲电场杀菌系统三场耦合的数学模型,模拟在脉冲电压V、脉宽τ、频率f流速v和温度T等条件下,NaCl溶液的流体特性、温度分布以及处理室中的电场分布,得出了同场处理室几何尺寸与温度和电场分布的关系,为优化处理室结构,改善杀菌效果提供重要依据.

  5. A mild pulsed electric field condition that improves acid tolerance, growth, and protease activity of Lactobacillus acidophilus LA-K and Lactobacillus delbrueckii subspecies bulgaricus LB-12.

    Science.gov (United States)

    Najim, N; Aryana, Kayanush J

    2013-06-01

    Pulsed electric field (PEF) processing involves the application of pulses of voltage for less than 1 s to fluid products placed between 2 electrodes. The effect of mild PEF on beneficial characteristics of probiotic bacteria Lactobacillus acidophilus and Lactobacillus delbrueckii ssp. bulgaricus is not clearly understood. The objective of this study was to determine the influence of mild PEF conditions on acid tolerance, growth, and protease activity of Lb. acidophilus LA-K and Lactobacillus delbrueckii ssp. bulgaricus LB-12. A pilot plant PEF system (OSU-4M; The Ohio State University, Columbus) was used. The PEF treatments were positive square unipolar pulse width of 3 µs, pulse period of 0.5s, electric field strength of 1 kV/cm, delay time of 20 µs, flow rate of 60 mL/min, and 40.5°C PEF treatment temperature. Both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 subjected to mild PEF conditions were acid tolerant until the end of the 120 min of incubation, unlike the Lb. bulgaricus control, which was not acid tolerant after 30 min. The mild PEF-treated Lb. acidophilus LA-K and Lb. bulgaricus LB-12 reached the logarithmic phase of growth an hour earlier than the control. Mild PEF conditions studied significantly improved acid tolerance, exponential growth, and protease activity of both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 compared with the control. The mild PEF conditions studied can be recommended for pretreating cultures to enhance these desirable attributes.

  6. Picosecond pulsed electric fields induce apoptosis in HeLa cells via the endoplasmic reticulum stress and caspase-dependent signaling pathways.

    Science.gov (United States)

    Chen, Wen-Juan; Xiong, Zheng-Ai; Zhang, Min; Yao, Chen-Guo; Zhao, Zhong-Yong; Hua, Yuan-Yuan; Zhou, Wei

    2013-03-01

    The non-invasive treatment of tumors with preserved fertility holds great promise. The application of pulsed electric field (PEF) is a new biomedical engineering technique for tumor therapy. Picosecond pulsed electric fields (psPEF) can be transferred to target deep tissue non-invasively and precisely; however, research of the biological effects of psPEF on cells is limited. Electric theory predicts that when the pulse duration decreases to nanoseconds and picoseconds, it will mainly affect organelles and lead to intracellular electromanipulations. Previous studies have shown that psPEF targets the mitochondria and induces apoptosis through a mitochondrial-mediated pathway in HeLa cells. The endoplasmic reticulum is also involved in the intrinsic pathways of apoptosis. In the present study, HeLa cells were exposed to psPEF to investigate the underlying mechanisms of apoptosis. MTT assay demonstrated that psPEF displayed strong growth inhibitory effects on HeLa cells. Treatment with psPEF led to marked cell apoptosis and cell cycle arrest at the G2/M phase. In addition, psPEF affected the phosphorylation levels of endoplasmic reticulum sensors and upregulated the expression of glucose-regulated protein 78 (GRP78), glucose-regulated protein 94 (GRP94) and CCAAT enhancer-binding protein (C/EBP) homologous protein (CHOP). These changes were accompanied by the elevation of intracellular Ca2+ concentrations. Furthermore, the activation of caspase-12, -9 and -3, led to the release of cytochrome c, as well as the upregulation of Bax and the downregulation of Bcl-2, as observed in the HeLa cells. Taken together, these data suggest that psPEF is an efficient apoptosis-inducing agent for HeLa cells, which exerts its effects, at least partially, via the endoplasmic reticulum stress and caspase-dependent signaling pathways.

  7. ANALYTICAL EXPRESSION FOR THE ELECTRIC FIELD OF THE SINGLE MODE LASER HOMOGENEOUS BROADENING IN THE PULSE REGIME

    Directory of Open Access Journals (Sweden)

    S. Ayadi

    2015-07-01

    Full Text Available The simplest model of the laser is that of a single mode system homogenously broadened. The dynamical behavior of this laser is described by three differential equations, called Haken-Lorenz equations[1],  similar to the Lorenz model [1] already known to predict deterministic chaos. In previous recent work [5-7] we have proposed a simple harmonic expansion method to obtain a series of harmonics terms that yield analytical solutions to the laser equations. ¶This method allows us to derive an analytical expression of the laser field amplitude  when this last  undergoes a  periodic oscillations around zero mean value. We also obtain an analytical expression of the pulsing frequency.

  8. NMR in pulsed magnetic field

    KAUST Repository

    Abou-Hamad, Edy

    2011-09-01

    Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

  9. Pulsed electric field mediated in vitro cellular response of fibroblast and osteoblast-like cells on conducting austenitic stainless steel substrate.

    Science.gov (United States)

    Dubey, Ashutosh Kumar; Agrawal, Parnika; Misra, R Devesh Kumar; Basu, Bikramjit

    2013-07-01

    This article reports the intermittent pulse electric field stimulus mediated in vitro cellular response of L929 mouse fibroblast/SaOS2 osteoblast-like cells on austenitic steel substrates in reference to the field strength dependent behavior. The cellular density and morphometric analyses revealed that the optimal electric (E) fields for the maximum cell density of adhered L929 (~270 % to that of untreated sample) and SaOS2 (~280 % to that of untreated sample) cells are 1 V (0.33 V/cm) and 2 V (0.67 V/cm), respectively. The trend in aspect ratio of elongated SaOS2 cells did not indicate any significant difference among the untreated and treated (up to 3.33 V/cm) cells. The average cell and nucleus areas (for SaOS2 cells) were increased with an increase in the applied voltage up to 8 V (2.67 V/cm) and reduced thereafter. However, the ratio of nucleus to total cell area was increased significantly on the application of higher voltages (2-10 V), indicating the possible influence of E-field on cell growth. Further, the cell density results were compared with earlier results obtained with sintered Hydroxyapatite (HA) and HA-BaTiO3 composites and such comparison revealed that the enhanced cell density on steel sample occurs upon application of much lower field strength and stimulation time. This indicates the possible role of substrate conductivity towards cell growth in pulsed E-field mediated culture conditions.

  10. SACCHARAOMYCES CEREVISIAE CELLS MEMBRANE DAMAGE BY PULSED ELECTRIC FIELD%脉冲电场处理对酿酒酵母细胞膜的影响

    Institute of Scientific and Technical Information of China (English)

    张鹰; 曾新安; 温其标

    2006-01-01

    应用脉冲电场(pulsed electric field,简称PEF)连续式处理系统对酿酒酵母进行了灭菌实验,并推测了PEF对酵母细胞致死作用与细胞膜结构改变之间的关系.结果显示,电场强度达到10 kV·cm-1时,电场能使酵母细胞显著失活(P<0.05),并随电场强度的增大和作用时间的延长灭菌效果越好.采用紫外分光光度计法和荧光偏振法分别检测了PEF处理对酿酒酵母细胞膜通透性和细胞膜流动性的影响.结果显示,电场强度仅达到5 kV·cm-1时,细胞膜的通透性和荧光各项异性值已显著增加(P<0.05),膜通透性随电场强度增大而增大,膜流动性随电场强度的增大和作用时间的延长而减小.这些现象表明,PEF对酿酒酵母作用时细胞膜是一个关键位点,细胞膜通透性增加和细胞膜流动性减小导致的细胞膜破坏是PEF致死酿酒酵母的主要原因.%The effect of pulsed electric field (PEF) treatment, applied in a continuous system, on Saccharomyces cerevisiae cells was investigated. Ultraviolet spectrophotometer and fluorescence polarization methods were used to investigate the cell membrane permeability and membrane fluidity respectively. The plate counting method was used to determine the viability of the cells. Results showed that S.cerevisiae cells were significantly inactivated when electric field strength was up to 10 kV·cm-1 (P<0.05), but the cells membrane permeability and fluorescence anisotropy increased remarkably when the electric field strength was only up to 5 kV·cm-1 (P<0.05), indicating the membrane of S. cerevisiae cells were damaged by PEF treatment. The cell membrane fluidity decreased with the increasing electric field strength and treatment time, and the membrane permeability increased with the increasing electric field strength. Results in this paper suggest that cell membrane is one of the most key site during the pulsed electric field treatment, and the increased membrane

  11. Pulsed electrical discharge in conductive solution

    Science.gov (United States)

    Panov, V. A.; Vasilyak, L. M.; Vetchinin, S. P.; Pecherkin, V. Ya; Son, E. E.

    2016-09-01

    Electrical discharge in a conductive solution of isopropyl alcohol in tap water (330 μ S cm-1) has been studied experimentally applying high voltage millisecond pulses (rise time  ˜0.4 μ \\text{s} , amplitude up to 15 kV, positive polarity) to a pin anode electrode. Dynamic current-voltage characteristics synchronized with high-speed images of the discharge were studied. The discharge was found to develop from high electric field region in the anode vicinity where initial conductive current with density  ˜100 A cm-2 results in fast heating and massive nucleation of vapor bubbles. Discharges in nucleated bubbles then produce a highly conductive plasma region and facilitate overheating instability development with subsequent formation of a thermally ionized plasma channel. The measured plasma channel propagation speed was 3-15 m s-1. A proposed thermal model of plasma channel development explains the low observed plasma channel propagation speed.

  12. Synergistic effects of nanosecond pulsed electric fields combined with low concentration of gemcitabine on human oral squamous cell carcinoma in vitro.

    Directory of Open Access Journals (Sweden)

    Jing Wang

    Full Text Available Treatment of cancer often involves uses of multiple therapeutic strategies with different mechanisms of action. In this study we investigated combinations of nanosecond pulsed electric fields (nsPEF with low concentrations of gemcitabine on human oral cancer cells. Cells (Cal-27 were treated with pulse parameters (20 pulses, 100 ns in duration, intensities of 10, 30 and 60 kV/cm and then cultured in medium with 0.01 µg/ml gemcitabine. Proliferation, apoptosis/necrosis, invasion and morphology of those cells were examined using MTT, flow cytometry, clonogenics, transwell migration and TEM assay. Results show that combination treatments of gemcitabine and nsPEFs exhibited significant synergistic activities versus individual treatments for inhibiting oral cancer cell proliferation and inducing apoptosis and necrosis. However, there was no apparent synergism for cell invasion. By this we demonstrated synergistic inhibition of Cal-27 cells in vitro by nsPEFs and gemcitabine. Synergistic behavior indicates that these two treatments have different sites of action and combination treatment allows reduced doses of gemcitabine and lower nsPEF conditions, which may provide better treatment for patients than either treatment alone while reducing systemic toxicities.

  13. Entanglement Generation by Electric Field Background

    OpenAIRE

    Ebadi, Zahra; Mirza, Behrouz

    2014-01-01

    The quantum vacuum is unstable under the influence of an external electric field and decays into pairs of charged particles, a process which is known as the Schwinger pair production. We propose and demonstrate that this electric field can generate entanglement. Using the Schwinger pair production for constant and pulsed electric fields, we study entanglement for scalar particles with zero spins and Dirac fermions. One can observe the variation of the entanglement produced for bosonic and fer...

  14. Entanglement Generation by Electric Field Background

    CERN Document Server

    Ebadi, Zahra

    2014-01-01

    The quantum vacuum is unstable under the influence of an external electric field and decays into pairs of charged particles, a process which is known as the Schwinger pair production. We propose and demonstrate that this electric field can generate entanglement. Using the Schwinger pair production for constant and pulsed electric fields, we study entanglement for scalar particles with zero spins and Dirac fermions. One can observe the variation of the entanglement produced for bosonic and fermionic modes with respect to different parameters.

  15. Dielectrics in electric fields

    CERN Document Server

    Raju, Gorur G

    2003-01-01

    Discover nontraditional applications of dielectric studies in this exceptionally crafted field reference or text for seniors and graduate students in power engineering tracks. This text contains more than 800 display equations and discusses polarization phenomena in dielectrics, the complex dielectric constant in an alternating electric field, dielectric relaxation and interfacial polarization, the measurement of absorption and desorption currents in time domains, and high field conduction phenomena. Dielectrics in Electric Fields is an interdisciplinary reference and text for professionals and students in electrical and electronics, chemical, biochemical, and environmental engineering; physical, surface, and colloid chemistry; materials science; and chemical physics.

  16. In vivo evidences of nanosecond pulsed electric fields for melanoma malignancy treatment on tumor-bearing BALB/c nude mice.

    Science.gov (United States)

    Guo, F; Yao, C; Li, C; Mi, Y; Peng, Q; Tang, J

    2014-08-01

    In order to get in vivo evidences of nanosecond pulsed electric fields (nsPEF) for skin tumor treatment, tumor models in 10 female BALB/c nude mice were established by inoculating them with human melanoma cells A375. These mice were randomly divided into treated group (exposed to nsPEF with intensity of 20 kV/cm and duration of 300 ns) and control group equally. Five days post-nsPEF treatment, tumor growth in the treated group was effectively inhibited (P growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) were observed by immunohistochemistry (P growth can be effectively inhibited by nsPEF, which activate two targets, apoptosis initiation and angiogenesis inhibition.

  17. Effect of pulsed electric field on Rhizoctorzia solani%脉冲电场对水稻纹枯菌的杀灭效果

    Institute of Scientific and Technical Information of China (English)

    冯学斌; 尹文庆; 王迎迎; 张美娜

    2013-01-01

    探讨了脉冲电场杀菌的机理,仿真分析了培养液中脉冲电场的分布情况,仿真结果表明:进入培养液内脉冲电场时域波形的脉宽都有不同程度的变窄;脉冲上升沿越陡峭,进入培养液内部的脉冲电场峰值越高,穿透性越好.对脉冲电场水稻纹枯菌杀灭效果进行了试验研究,在同轴型处理室中分别以不同幅值的电磁脉冲(频率为2.5 Hz)和不同的作用时间对10-4稀释的水稻纹枯菌菌液进行处理,试验结果表明:当电磁脉冲的幅值较低时,可以通过延长灭菌的时间来提高灭菌效果;而幅值较高时,则脉冲幅值为灭菌效果的主要影响因素,延长灭菌时间的意义不大.%Principle of pulse electric field (PEF) pasteurization was discussed and the distribution of the PEF in culture fluid was analyzed through simulation, the simulation results showed that pulse widths of the PEF time domain waveform in culture fluid were narrowed at different degrees. Peak of the PEF was higher and penetrating was better when the input pulse rising edge was steeper. Effects of PEF sterilization on Rhizoctorzia solani were studied, liquid of Rhizoctorzia solani diluted to 10-4 were processed in the coaxial treatment chamber with different amplitudes of the electromagnetic pulse (EMP, a frequency of 2. 5 Hz) and different action duration. The experiments showed that PEF pasteurization effect could be enhanced by extending the work time when the pulse amplitude was lower; when the amplitude was higher, the main influence factor of PEF pasteurization was the pulse amplitude while it was not very meaningful to extend the work time.

  18. An assessment of the impact of pulsed electric fields processing factors on oxidation, color, texture, and sensory attributes of turkey breast meat.

    Science.gov (United States)

    Arroyo, Cristina; Eslami, Sara; Brunton, Nigel P; Arimi, Joshua M; Noci, Francesco; Lyng, James G

    2015-05-01

    Pulsed electric fields (PEF) is a novel nonthermal technology that has the potential to cause physical disruption to muscle tissue which in turn could alter the sensorial aspects of meat in both a positive (e.g., enhanced tenderization) and a negative way (e.g., off-flavor development). If there is a risk of off-flavor development it should be identified prior to embarking on an extensive investigation on PEF in meat tenderization and turkey meat was chosen for this purpose as it is particularly prone to oxidation. The objective of this study was to investigate the effect of various PEF treatments on the quality attributes of turkey breast meat. Turkey breast meat obtained 1 d postslaughter was treated in a batch PEF chamber with increasing electric field strength up to 3 kV/cm and analyzed for lipid oxidation by thiobarbituric acid reactive substances assay (TBARS) with up to 5 d storage at 4°C in aerobic conditions. In a separate experiment, turkey breast meat samples were exposed to PEF under various combinations of pulse number, frequency, and voltage. Following PEF treatments weight loss, cook loss, lipid oxidation, texture, and color were assessed by instrumental methods. A sensory analysis was also performed to determine consumer acceptability for color, texture, and odor of the samples. Lipid oxidation in all PEF-treated samples progressed at the same rate with storage as the untreated samples and was not found to be significantly different to the control. Under the conditions examined PEF treatments did not induce differences in instrumentally measured weight loss, cook loss, lipid oxidation, texture, and color (raw and cooked) either on fresh or frozen samples. However, the sensory evaluation suggested that panelists could detect slight differences between the PEF-treated samples and the controls in terms of texture and odor.

  19. Heat and pulsed electric field resistance of pigmented and non-pigmented enterotoxigenic strains of Staphylococcus aureus in exponential and stationary phase of growth.

    Science.gov (United States)

    Cebrián, G; Sagarzazu, N; Pagán, R; Condón, S; Mañas, P

    2007-09-30

    The survival of four enterotoxigenic strains of Staphylococcus aureus (with different pigment content) to heat and to pulsed electric fields (PEF) treatments, and the increase in resistance to both processing stresses associated with entrance into stationary phase was examined. Survival curves to heat (58 degrees C) and to PEF (26 kV/cm) of cells in the stationary and in the exponential phase of growth were obtained. Whereas a wide variation in resistance to heat treatments was detected amongst the four strains, with decimal reduction time values at 58 degrees C (D(58 degrees C)) ranging from 0.93 to 0.20 min, the resistance to PEF was very similar. The occurrence of a higher tolerance to heat in stationary phase was coincident with a higher content in carotenoid pigmentation in S. aureus colonies. However, cells of the most heat resistant (pigmented) and the most heat sensitive (non-pigmented) strains in the mid-exponential phase of growth showed similar resistance to heat and to PEF. Therefore the increase in thermotolerance upon entrance into stationary phase of growth was more marked for the pigmented strains. Recovery in anaerobic conditions particularly enhanced survival to heat treatments in a non-pigmented strain. Strain CECT 4630, which possess a deficient sigma B activity, showed low heat resistance, low pigmentation, and reduced increase in thermotolerance in stationary phase. These results indicate that the magnitude of the development of a higher heat resistance in S. aureus in stationary phase is positively related to the carotenoid content of the strain. The development of tolerance to pulsed electric field was less relevant and not linked to the carotenoid content.

  20. 高压脉冲电场对微生物的灭活作用研究进展%Research Progress in the Effect of High-voltage Pulsed Electric Field on Microorganism Inactivation

    Institute of Scientific and Technical Information of China (English)

    陈新梅; 薛文静; 赵元

    2016-01-01

    Objective:To review the inactivation effect of high-voltage pulsed electric field on microorganism to provid theoretical basis for the further research and sterilization application of high-voltage pulsed electric field. Methods:The combination of high-volt-age pulse electric field, microbiology and pulse electric field as the keywords, the research results of high-voltage pulsed electric field on microbial inactivation in PubMed, CNKI, VIP Chinese journal full text database and Wanfang database during 2010 and 2015 were retrieved, summarized and reviewed. Results:As a non-thermal sterilization technology, high-voltage pulsed electric field not only had the characteristics of short sterilization time, narrow increasing extent of temperature and low energy consumption, but also could keep the original flavor of food. Conclusion:With the development of related technology, high-voltage pulsed electric field is expected to re-alize industrialization.%目的::综述高压脉冲电场对微生物的灭活作用,为进一步研究和应用高压脉冲电场灭菌提供理论基础。方法:以“高压脉冲电场”、“微生物”、“Pulse Electric Field”等组合为关键词,检索2010~2015年PubMed、中国知网、维普中文期刊全文数据库、万方数据库中有关高压脉冲电场对微生物的灭活作用的研究成果,进行总结和综述。结果:高压脉冲电场作为一种非热灭菌技术,不仅具有灭菌时间短、升温幅度小、耗能少的特点,还能保持食品原有风味不变。结论:随着相关技术的发展,高压脉冲电场有望实现产业化。

  1. Pulsed Electromagnetic Field Assisted in vitro Electroporation: A Pilot Study

    Science.gov (United States)

    Novickij, Vitalij; Grainys, Audrius; Lastauskienė, Eglė; Kananavičiūtė, Rūta; Pamedytytė, Dovilė; Kalėdienė, Lilija; Novickij, Jurij; Miklavčič, Damijan

    2016-09-01

    Electroporation is a phenomenon occurring due to exposure of cells to Pulsed Electric Fields (PEF) which leads to increase of membrane permeability. Electroporation is used in medicine, biotechnology, and food processing. Recently, as an alternative to electroporation by PEF, Pulsed ElectroMagnetic Fields (PEMF) application causing similar biological effects was suggested. Since induced electric field in PEMF however is 2–3 magnitudes lower than in PEF electroporation, the membrane permeabilization mechanism remains hypothetical. We have designed pilot experiments where Saccharomyces cerevisiae and Candida lusitaniae cells were subjected to single 100–250 μs electrical pulse of 800 V with and without concomitant delivery of magnetic pulse (3, 6 and 9 T). As expected, after the PEF pulses only the number of Propidium Iodide (PI) fluorescent cells has increased, indicative of membrane permeabilization. We further show that single sub-millisecond magnetic field pulse did not cause detectable poration of yeast. Concomitant exposure of cells to pulsed electric (PEF) and magnetic field (PMF) however resulted in the increased number PI fluorescent cells and reduced viability. Our results show increased membrane permeability by PEF when combined with magnetic field pulse, which can explain electroporation at considerably lower electric field strengths induced by PEMF compared to classical electroporation.

  2. Comparative Study on the Grain Refinement of Al-Si Alloy Solidified under the Impact of Pulsed Electric Current and Travelling Magnetic Field

    Directory of Open Access Journals (Sweden)

    Yunhu Zhang

    2016-07-01

    Full Text Available It is high of commercial importance to generate the grain refinement in alloys during solidification by means of electromagnetic fields. Two typical patterns of electromagnetic fields, pulsed electric currents (ECP and traveling magnetic field (TMF, are frequently employed to produce the finer equiaxed grains in solidifying alloys. Various mechanisms were proposed to understand the grain refinement in alloys caused by ECP and TMF. In this paper, a comparative study is carried out in the same solidification regime to investigate the grain refinement of Al-7 wt. %Si alloy driven by ECP and TMF. Experimental results show that the application of ECP or TMF can cause the same grain refinement occurrence period, during which the refinement of primary Al continuously occurs. In addition, the related grain refinement mechanisms are reviewed and discussed, which shows the most likely one caused by ECP and TMF is the promoted dendrite fragmentation as the result of the ECP-induced or TMF-induced forced flow. It suggests that the same grain refinement process in alloys is provoked when ECP and TMF are applied in the same solidification regime, respectively.

  3. Propagation of electric field of the few-cycle femtosecond pulse in nonlinear Kerr medium%周期量级飞秒脉冲电场在非线性克尔介质中的传输∗

    Institute of Scientific and Technical Information of China (English)

    刘丹; 洪伟毅; 郭旗

    2016-01-01

    In this paper, the propagation of a few-cycle femtosecond pulse in a nonlinear Kerr medium is studied by the method of time-transformation. The time-transformation approach can greatly improve the computational efficiency. Because the width of electric field of the few-cycle femtosecond pulse is less than the characteristic time of Raman response in a nonlinear medium, it is observed that the electric field of the pulse experiences a significant deformation and breaks into a Raman soliton and the dispersion waves during the propagation, which can be attributed to strongly nonlocal nonlinearity. A deeper investigation of the time-frequency distributions for both the Raman soliton and the dispersion waves is also included. Since the pulse contains only few cycles, the carrier-envelope phase (CEP) of the pulse plays an important role in the process of nonlinear propagation. The numerical results show the CEP-dependence in the process of nonlinear propagation: the phase changes for both the Raman soliton and the dispersive waves are just equal to the CEP change of the initial pulse, which indicates that the CEP of the pulse is linearly transmitted in the process of nonlinear propagation. This phenomenon can be attributed to the fact that the phase change due to the nonlinearity is only dependent on the intensities of the fields of both the Raman soliton and the dispersion wave, which are unchanged for all the CEPs.

  4. Pulsed photoelectric field emission from needle cathodes

    CERN Document Server

    Hernandez-Garcia, C

    2002-01-01

    Experiments have been carried out to measure the current emitted by tungsten needles with 1-mu m tip radius operated up to 50 kV. This corresponds to electric fields in the order of 10 sup 9 to 10 sup 1 sup 0 V/m. The needles were illuminated with 10-ns laser pulses at 532, 355 and 266 nm. The laser intensity was varied from 10 sup 1 sup 0 to 10 sup 1 sup 2 W/m sup 2 , limited by damage to the needle tip. The observed quantum efficiency depends on the wavelength and the electric field, approaching unity at the highest electric fields when illuminated at 266 nm. Peak currents up to 100 mA were observed in nanosecond pulses, corresponding to an estimated brightness of 10 sup 1 sup 6 A/m sup 2 sr. Since the current is controlled by the laser intensity, with only a weak voltage dependence, these cathodes can be used for infrared and ultraviolet tabletop free-electron lasers and other applications that demand short electron-beam pulses with high brightness.

  5. Application of Pulsed Electrical Fields for Advanced Cooling and Water Recovery in Coal-Fired Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Young Cho; Alexander Fridman

    2009-04-02

    The overall objective of the present work was to develop technologies to reduce freshwater consumption in a cooling tower of coal-based power plant so that one could significantly reduce the need of make-up water. The specific goal was to develop a scale prevention technology based an integrated system of physical water treatment (PWT) and a novel filtration method so that one could reduce the need for the water blowdown, which accounts approximately 30% of water loss in a cooling tower. The present study investigated if a pulsed spark discharge in water could be used to remove deposits from the filter membrane. The test setup included a circulating water loop and a pulsed power system. The present experiments used artificially hardened water with hardness of 1,000 mg/L of CaCO{sub 3} made from a mixture of calcium chloride (CaCl{sub 2}) and sodium carbonate (Na{sub 2}CO{sub 3}) in order to produce calcium carbonate deposits on the filter membrane. Spark discharge in water was found to produce strong shockwaves in water, and the efficiency of the spark discharge in cleaning filter surface was evaluated by measuring the pressure drop across the filter over time. Results showed that the pressure drop could be reduced to the value corresponding to the initial clean state and after that the filter could be maintained at the initial state almost indefinitely, confirming the validity of the present concept of pulsed spark discharge in water to clean dirty filter. The present study also investigated the effect of a plasma-assisted self-cleaning filter on the performance of physical water treatment (PWT) solenoid coil for the mitigation of mineral fouling in a concentric counterflow heat exchanger. The self-cleaning filter utilized shockwaves produced by pulse-spark discharges in water to continuously remove scale deposits from the surface of the filter, thus keeping the pressure drop across the filter at a relatively low value. Artificial hard water was used in the

  6. Bag model for DNA migration during pulsed-field electrophoresis.

    OpenAIRE

    Chu, G

    1991-01-01

    A model for pulsed-field electrophoresis was developed by picturing large DNA as a deformable "bag" that (i) moves with limiting mobility in a continuous electric field, (ii) adopts an orientation aligned with the field direction, and (iii) reorients after a change in field direction in a size-dependent manner. The model correctly predicted the resolution of large DNA in a pulsed field including the surprising phenomena of mobility inversion, lateral band spreading, and improved resolution fo...

  7. Sodium benzoate, potassium sorbate, and citric acid induce sublethal injury and enhance pulsed electric field inactivation of E. coli O157:H7 and nonpathogenic surrogate E. coli in strawberry juice

    Science.gov (United States)

    Current FDA regulations require that juice processors effect a 5 log CFU/ml reduction of a target pathogen prior to distributing products. Whereas thermal pasteurization reduces the sensory characteristics of juice by altering flavor components, pulsed electric field (PEF) treatment can be conducte...

  8. 高压脉冲电场灭菌方法研究概况%Research on the High-voltage Pulsed Electric Field Sterilization Method

    Institute of Scientific and Technical Information of China (English)

    陈新梅; 李莹; 陈新华

    2014-01-01

    The high-voltage pulsed electric field (PEF) sterilization has significant advantages such as a short process-ing time,low energy consumption,small temperature rise,high sterilization rate and not affecting the effective components of drugs,and so on. Based on the review of the mechanism of PEF sterilization,sterilization devices and the possible influ-encing factors,and the comparison of other sterilization methods,the evaluation of the PEF sterilization method was made and the existing problems and commercial prospects in the fields of food and pharmaceuticals were discussed.%高压脉冲电场灭菌具有处理时间短、耗能低、升温小、灭菌率高、不影响药物的有效成分等显著优点,本文通过对高压脉冲电场灭菌作用机理、灭菌装置、可能的影响因素总结及与其他灭菌方式的比较,对高压脉冲电场灭菌方式进行评价,并探讨其现存问题及在食品、药品领域的应用前景。

  9. Nanosecond pulsed electric field suppresses development of eyes and germ cells through blocking synthesis of retinoic acid in Medaka (Oryzias latipes.

    Directory of Open Access Journals (Sweden)

    Eri Shiraishi

    Full Text Available Application of nanosecond pulsed electric fields (nsPEFs has attracted rising attention in various scientific fields including medical, pharmacological, and biological sciences, although its effects and molecular mechanisms leading to the effects remain poorly understood. Here, we show that a single, high-intensity (10-30 kV/cm, 60-ns PEF exposure affects gene expression and impairs development of eyes and germ cells in medaka (Oryzias latipes. Exposure of early blastula stage embryos to nsPEF down-regulated the expression of several transcription factors which are essential for eye development, causing abnormal eye formation. Moreover, the majority of the exposed genetic female embryos showed a fewer number of germ cells similar to that of the control (unexposed genetic male at 9 days post-fertilization (dpf. However, all-trans retinoic acid (atRA treatment following the exposure rescued proliferation of germ cells and resumption of normal eye development, suggesting that the phenotypes induced by nsPEF are caused by a decrease of retinoic acid levels. These results confirm that nsPEFs induce novel effects during embryogenesis in medaka.

  10. Safety of pulsed electric devices.

    Science.gov (United States)

    Nimunkar, Amit J; Webster, John G

    2009-01-01

    The strength-duration curve for tissue excitation can be modeled by a parallel resistor-capacitor circuit that has a time constant. We tested several short-duration electric generators: five electric fence energizers, the Taser X26 and a high-frequency generator to determine their current-versus-time waveforms. We estimated their safety characteristics using existing IEC and UL standards for electric fence energizers. The current standards are difficult to follow, with cumbersome calculations, and do not explicitly explain the physiological relevance of the calculated parameters. Hence we propose a new standard. The proposed new standard would consist of a physical RC circuit with a certain time constant. The investigator would discharge the device into a passive resistor-capacitor circuit and measure the resulting maximum voltage. If the maximum voltage does not exceed a limit, the device passes the test.

  11. Nanosecond pulsed electric fields induce poly(ADP-ribose) formation and non-apoptotic cell death in HeLa S3 cells

    Energy Technology Data Exchange (ETDEWEB)

    Morotomi-Yano, Keiko; Akiyama, Hidenori [Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan); Yano, Ken-ichi, E-mail: yanoken@kumamoto-u.ac.jp [Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-8555 (Japan)

    2013-08-30

    Highlights: •Nanosecond pulsed electric field (nsPEF) is a new and unique means for life sciences. •Apoptosis was induced by nsPEF exposure in Jurkat cells. •No signs of apoptosis were detected in HeLa S3 cells exposed to nsPEFs. •Formation of poly(ADP-ribose) was induced in nsPEF-exposed HeLa S3 cells. •Two distinct modes of cell death were activated by nsPEF in a cell-dependent manner. -- Abstract: Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs.

  12. High- voltage Pulsed Electric Field Sterilization Equipment and Flow Control%高压脉冲电场灭菌设备及其流量控制

    Institute of Scientific and Technical Information of China (English)

    林荣华; 李伟光

    2012-01-01

    In order to optimize the sterilization effect of high-voltage pulsed electric field sterilization equipment, this paper analyzes its function according the tactors of the enfluence on the system, designs the overall structure and PLC-based flow control system by the way of frequency control of motor speed, describes the structure and principle of high-voltage pulse generator and the theory and realization of the flow control based on frequency control as well as the realization of communication between inverters and PLC with RS-485. The result shows that the equipment is able to control and adjust key process parameters well, comtro the flow by a simple and reliable way, and achieve high effective and fast sterilization.%为优化高压脉冲电场灭菌设备的灭菌效果,根据其影响因素进行了系统功能需求分析,设计了设备的总体架构,采用变频调速的方法,设计了基于PLC的流量控制系统.简述了高压脉冲发生器的结构及原理,重点介绍了基于变频调速的流量控制原理与实现,变频器与PLC的RS - 485通信的实现.实验表明,设备实现了关键工艺参数可调可控,运行效果良好,简单可靠地实现了流量的控制,实现了快速高效灭菌.

  13. Electric breakdown during the pulsed current spreading in the sand

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyak, L. M., E-mail: vasilyak@ihed.ras.ru; Vetchinin, S. P.; Panov, V. A.; Pecherkin, V. Ya.; Son, E. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2016-03-15

    Processes of spreading of the pulsed current from spherical electrodes and an electric breakdown in the quartz sand are studied experimentally. When the current density on the electrode exceeds the critical value, a nonlinear reduction occurs in the grounding resistance as a result of sparking in the soil. The critical electric field strengths for ionization and breakdown are determined. The ionization-overheating instability is shown to develop on the electrode, which leads to the current contraction and formation of plasma channels.

  14. Heredity of Aluminum Melt Caused by Electric Pulse Modification (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-zhong; QI Jin-gang; DU Hui-ling; ZHANG Zhen-bin

    2007-01-01

    The heredity of aluminum melt under the action of pulse electric field was investigated by means of the remelt experiment. A new hereditary criterion under this condition was proposed; in the meantime, the differential transferability of genetic carrier in activated melt among filial generations was validated with the aid of DSC.

  15. Second harmonic generation in NLO polymers excited by Surface Plasmon enhanced electric field induced by femtosecond optical pulses

    Directory of Open Access Journals (Sweden)

    Kawata Y.

    2013-03-01

    Full Text Available We will report second harmonic generation (SHG in nonlinear optical (NLO polymers excited by surface plasmon enhanced optical fields. The surface plasmon (SP polariton was excited in an attenuated total reflection geometry having the Kretchmann configuration. The NLO polymers, consisting of Disperse Red1 as guest chromophores and poly (methyl methacrylate as host materials, were coated upon the Ag layers. Our experimental results indicated that the SHG signal intensity from the polymer coated Ag films was more than 10 times higher than that from the non-coated Ag films. The SHG autocorrelation traces excited by SP-enhanced fields were also studied and the correlation time was shorter than 150 fs, the temporal resolutions of the present spectrometer.

  16. Nanosecond pulsed electric fields induce poly(ADP-ribose) formation and non-apoptotic cell death in HeLa S3 cells.

    Science.gov (United States)

    Morotomi-Yano, Keiko; Akiyama, Hidenori; Yano, Ken-ichi

    2013-08-30

    Nanosecond pulsed electric fields (nsPEFs) have recently gained attention as effective cancer therapy owing to their potency for cell death induction. Previous studies have shown that apoptosis is a predominant mode of nsPEF-induced cell death in several cell lines, such as Jurkat cells. In this study, we analyzed molecular mechanisms for cell death induced by nsPEFs. When nsPEFs were applied to Jurkat cells, apoptosis was readily induced. Next, we used HeLa S3 cells and analyzed apoptotic events. Contrary to our expectation, nsPEF-exposed HeLa S3 cells exhibited no molecular signs of apoptosis execution. Instead, nsPEFs induced the formation of poly(ADP-ribose) (PAR), a hallmark of necrosis. PAR formation occurred concurrently with a decrease in cell viability, supporting implications of nsPEF-induced PAR formation for cell death. Necrotic PAR formation is known to be catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1), and PARP-1 in apoptotic cells is inactivated by caspase-mediated proteolysis. Consistently, we observed intact and cleaved forms of PARP-1 in nsPEF-exposed and UV-irradiated cells, respectively. Taken together, nsPEFs induce two distinct modes of cell death in a cell type-specific manner, and HeLa S3 cells show PAR-associated non-apoptotic cell death in response to nsPEFs.

  17. Quality-related enzymes in plant-based products: effects of novel food processing technologies part 2: pulsed electric field processing.

    Science.gov (United States)

    Terefe, Netsanet Shiferaw; Buckow, Roman; Versteeg, Cornelis

    2015-01-01

    Pulsed electric field (PEF) processing is an effective technique for the preservation of pumpable food products as it inactivates vegetative microbial cells at ambient to moderate temperature without significantly affecting the nutritional and sensorial quality of the product. However, conflicting views are expressed about the effect of PEF on enzymes. In this review, which is part 2 of a series of reviews dealing with the effectiveness of novel food preservation technologies for controlling enzymes, the scientific literature over the last decade on the effect of PEF on plant enzymes is critically reviewed to shed more light on the issue. The existing evidence indicates that PEF can result in substantial inactivation of most enzymes, although a much more intense process is required compared to microbial inactivation. Depending on the processing condition and the origin of the enzyme, up to 97% inactivation of pectin methylesterase, polyphenol oxidase, and peroxidase as well as no inactivation have been reported following PEF treatment. Both electrochemical effects and Ohmic heating appear to contribute to the observed inactivation, although the relative contribution depends on a number of factors including the origin of the enzyme, the design of the PEF treatment chamber, the processing condition, and the composition of the medium.

  18. Impact of pulsed electric field on electrodialysis process performance and membrane fouling during consecutive demineralization of a model salt solution containing a high magnesium/calcium ratio.

    Science.gov (United States)

    Cifuentes-Araya, Nicolás; Pourcelly, Gérald; Bazinet, Laurent

    2011-09-01

    Pulsed electric fields (PEFs), hashed modes of current consisting in the application of a constant current density during a fixed time (Ton) followed by a pause lapse (Toff), were recently demonstrated as an effective alternative for mineral fouling mitigation and process intensification during electrodialysis (ED) treatments. Recent ED studies have continuously reported a considerable mineral fouling formation on ion-exchange membranes, especially during the demineralization of solutions containing a high Mg/Ca ratio and a basified concentrate solution. The aim of this study was to evaluate the process performance under two different PEF conditions on a mineral solution containing a mineral mixture giving a high Mg(2+)/Ca(2+) ratio of 2/5. Two different pause-lapse durations (PEF ratio 1 (Ton/Toff 10s/10s); PEF ratio 0.3 (Ton/Toff 10s/33.3 s)) during consecutive ED treatments and their comparison with dc current were evaluated at a current density of 40 mA/cm(2). Our results showed that PEFs resulted in an intensification of ED process, enhancing the demineralization rates (DRs), reducing the system resistance (SR), and reducing the fouling and energy consumption (EC). PEF ratio 1 was the most optimal condition among the current regimes applied, leading to faster and higher demineralization rates due to a lower fouling and with low energy consumption during all consecutive runs.

  19. Nanosecond pulsed electric field inhibits cancer growth followed by alteration in expressions of NF-κB and Wnt/β-catenin signaling molecules.

    Directory of Open Access Journals (Sweden)

    Zhigang Ren

    Full Text Available Cancer remains a leading cause of death worldwide and total number of cases globally is increasing. Novel treatment strategies are therefore desperately required for radical treatment of cancers and long survival of patients. A new technology using high pulsed electric field has emerged from military application into biology and medicine by applying nsPEF as a means to inhibit cancer. However, molecular mechanisms of nsPEF on tumors or cancers are still unclear. In this paper, we found that nsPEF had extensive biological effects in cancers, and clarified its possible molecular mechanisms in vitro and in vivo. It could not only induce cell apoptosis via dependent-mitochondria intrinsic apoptosis pathway that was triggered by imbalance of anti- or pro-apoptosis Bcl-2 family proteins, but also inhibit cell proliferation through repressing NF-κB signaling pathway to reduce expressions of cyclin proteins. Moreover, nsPEF could also inactivate metastasis and invasion in cancer cells by suppressing Wnt/β-Catenin signaling pathway to down-regulating expressions of VEGF and MMPs family proteins. More importantly, nsPEF could function safely and effectively as an anti-cancer therapy through inducing tumor cell apoptosis, destroying tumor microenvironment, and depressing angiogenesis in tumor tissue in vivo. These findings may provide a creative and effective therapeutic strategy for cancers.

  20. Pulsed electric field improves the bioprotective capacity of purées for different coloured carrot cultivars against H2O2-induced oxidative damage.

    Science.gov (United States)

    Leong, Sze Ying; Oey, Indrawati; Burritt, David John

    2016-04-01

    This research aimed to study the effect of pulsed electric field (PEF) processing on the bioprotective capacity of carrot purée for White Belgian, Yellow Solar, Nantes, Nutri Red and Purple Haze cultivars against H2O2-induced oxidative damage. The bioprotective capacity was determined using cell viability, membrane integrity and nitric oxide (NO) production in a human Caco-2 cell culture assay. Total carotenoids, total anthocyanins, total vitamin C and total phenolics were also evaluated. Compared to the untreated purée, Purple Haze and Nutri Red processed at 303 kJ/kg completely increased Caco-2 cells resistance towards oxidative damage by recovering the cell viability and inhibiting NO production. For cultivar with low carotenoid levels, i.e. Yellow Solar, the application of 0.8 kV/cm resulted in a higher total carotenoid content in the purée than its untreated counterpart, leading to an improved bioprotective effect. This study clearly shows that PEF could add value to carrots by maximising bioprotective effects.

  1. Nanosecond pulsed electric field inhibits cancer growth followed by alteration in expressions of NF-κB and Wnt/β-catenin signaling molecules.

    Science.gov (United States)

    Ren, Zhigang; Chen, Xinhua; Cui, Guangying; Yin, Shengyong; Chen, Luyan; Jiang, Jianwen; Hu, Zhenhua; Xie, Haiyang; Zheng, Shusen; Zhou, Lin

    2013-01-01

    Cancer remains a leading cause of death worldwide and total number of cases globally is increasing. Novel treatment strategies are therefore desperately required for radical treatment of cancers and long survival of patients. A new technology using high pulsed electric field has emerged from military application into biology and medicine by applying nsPEF as a means to inhibit cancer. However, molecular mechanisms of nsPEF on tumors or cancers are still unclear. In this paper, we found that nsPEF had extensive biological effects in cancers, and clarified its possible molecular mechanisms in vitro and in vivo. It could not only induce cell apoptosis via dependent-mitochondria intrinsic apoptosis pathway that was triggered by imbalance of anti- or pro-apoptosis Bcl-2 family proteins, but also inhibit cell proliferation through repressing NF-κB signaling pathway to reduce expressions of cyclin proteins. Moreover, nsPEF could also inactivate metastasis and invasion in cancer cells by suppressing Wnt/β-Catenin signaling pathway to down-regulating expressions of VEGF and MMPs family proteins. More importantly, nsPEF could function safely and effectively as an anti-cancer therapy through inducing tumor cell apoptosis, destroying tumor microenvironment, and depressing angiogenesis in tumor tissue in vivo. These findings may provide a creative and effective therapeutic strategy for cancers.

  2. 高压脉冲电场静态处理室的研制%Developing on the Static Chamber of High-Voltage Pulsed Electric Field

    Institute of Scientific and Technical Information of China (English)

    平雪良; 刘翠; 杨瑞金; 赵伟

    2010-01-01

    高压脉冲电场(Pulsed Electric Field, PEF)是一项极具前景的食品非热杀菌技术,其处理关键部件--处理室直接影响杀菌效果.作者设计了电场分布均匀、处理物料容量可调、安全可靠的PEF处理室,应用该PEF处理室对接种大肠杆菌的液蛋进行杀菌,当电场强度为34.2 kV/cm处理时间为400 μs时,原样品菌体浓度为106~107 cfu/mL,大肠杆菌细菌数量降低了约5.05个对数,从而说明作者设计的静态处理室是可行的,可以进行杀菌钝酶等相关机理研究.

  3. Osmotic dehydration of some agro-food tissue pre-treated by pulsed electric field: Impact of impeller’s Reynolds number on mass transfer and color

    Directory of Open Access Journals (Sweden)

    E. Amami

    2014-01-01

    Full Text Available Tissues of apple, carrot and banana were pre-treated by pulsed electric field (PEF and subsequently osmotically dehydrated in an agitated flask at ambient temperature using a 65% sucrose solution as osmotic medium. The effect of stirring intensity was investigated through water loss (WL and solid gain (SG. Changes in product color were also considered to analyze the impact of the treatment. The impeller’s Reynolds number was used to quantify the agitation. The Reynolds number remained inferior to 300 thus displaying laminar flow regime. Water loss (WL and solid gain (SG increase with the increase of Reynolds number. Mass transfer in osmotic dehydration of all three test particles has been studied on the basis of a two-exponential kinetic model. Then, mass transfer coefficients were related to the agitation intensity. This paper shows that the proposed empirical model is able to describe mass transfer phenomena in osmotic dehydration of these tissues. It is also shown that a higher agitation intensity improves both the kinetics of water loss and solid gain.

  4. Structural and biochemical changes induced by pulsed electric field treatments on Cabernet Sauvignon grape berry skins: impact on cell wall total tannins and polysaccharides.

    Science.gov (United States)

    Cholet, Céline; Delsart, Cristèle; Petrel, Mélina; Gontier, Etienne; Grimi, Nabil; L'hyvernay, Annie; Ghidossi, Remy; Vorobiev, Eugène; Mietton-Peuchot, Martine; Gény, Laurence

    2014-04-02

    Pulsed electric field (PEF) treatment is an emerging technology that is arousing increasing interest in vinification processes for its ability to enhance polyphenol extraction performance. The aim of this study was to investigate the effects of PEF treatment on grape skin histocytological structures and on the organization of skin cell wall polysaccharides and tannins, which, until now, have been little investigated. This study relates to the effects of two PEF treatments on harvested Cabernet Sauvignon berries: PEF1 (medium strength (4 kV/cm); short duration (1 ms)) and PEF2 (low intensity (0.7 kV/cm); longer duration (200 ms)). Histocytological observations and the study of levels of polysaccharidic fractions and total amounts of tannins allowed differentiation between the two treatments. Whereas PEF1 had little effect on the polyphenol structure and pectic fraction, PEF2 profoundly modified the organization of skin cell walls. Depending on the PEF parameters, cell wall structure was differently affected, providing variable performance in terms of polyphenol extraction and wine quality.

  5. Membrane Destruction and DNA Binding of Staphylococcus aureus Cells Induced by Carvacrol and Its Combined Effect with a Pulsed Electric Field.

    Science.gov (United States)

    Wang, Lang-Hong; Wang, Man-Sheng; Zeng, Xin-An; Zhang, Zhi-Hong; Gong, De-Ming; Huang, Yan-Bo

    2016-08-17

    Carvacrol (5-isopropyl-2-methylphenol, CAR) is an antibacterial ingredient that occurs naturally in the leaves of the plant Origanum vulgare. The antimicrobial mechanism of CAR against Staphylococcus aureus ATCC 43300 was investigated in the study. Analysis of the membrane fatty acids by gas chromatography-mass spectrometry (GC-MS) showed that exposure to CAR at low concentrations induced a marked increase in the level of unbranched fatty acids (from 34.90 ± 1.77% to 62.37 ± 4.26%). Moreover, CAR at higher levels severely damaged the integrity and morphologies of the S. aureus cell membrane. The DNA-binding properties of CAR were also investigated using fluorescence, circular dichroism, molecular modeling, and atomic-force microscopy. The results showed that CAR bound to DNA via the minor-groove mode, mildly perturbed the DNA secondary structure, and induced DNA molecules to be aggregated. Furthermore, a combination of CAR with a pulsed-electric field was found to exhibit strong synergistic effects on S. aureus.

  6. Comparative study of pulsed electric field and thermal processing of apple juice with particular consideration of juice quality and enzyme deactivation.

    Science.gov (United States)

    Schilling, Susanne; Schmid, Sandra; Jäger, Henry; Ludwig, Michael; Dietrich, Helmut; Toepfl, Stefan; Knorr, Dietrich; Neidhart, Sybille; Schieber, Andreas; Carle, Reinhold

    2008-06-25

    As an alternative to thermal pasteurization, pulsed electric fields (PEF) were applied to apple juices on laboratory and pilot plant scale, investigating the effects on juice quality. PEF application still falls under the EU Novel Food Regulation. Consequently, extensive investigation of quality parameters is a prerequisite to prove substantial equivalence of juices resulting from the novel process and conventional production, respectively. Juice composition was not affected by PEF treatment. However, browning of the juices provided evidence of residual enzyme activities. On laboratory scale, complete deactivation of peroxidase (POD) and polyphenoloxidase (PPO) was achieved when PEF treatment and preheating of the juices to 60 degrees C were combined. Under these conditions, a synergistic effect of heat and PEF was observed. On pilot plant scale, maximum PPO deactivation of 48% was achieved when the juices were preheated to 40 degrees C and PEF-treated at 30 kV/cm (100 kJ/kg). Thus, minimally processed juices resulted from PEF processing, when applied without additional conventional thermal preservation. Since this product type was characterized by residual native enzyme activities and nondetectable levels of 5-hydroxymethylfurfural, also when preheating up to 40 degrees C was included, it ranged between fresh and pasteurized juices regarding consumers' expectation of freshness and shelf life. Consistent with comparable iron contents among all juice samples, no electrode corrosion was observed under the PEF conditions applied.

  7. Effects of pulsed electric field on secondary metabolism of Vitis vinifera L. cv. Gamay Fréaux suspension culture and exudates.

    Science.gov (United States)

    Cai, Zhenzhen; Riedel, Heidi; Thaw Saw, Nay Min Min; Kütük, Onur; Mewis, Inga; Jäger, Henry; Knorr, Dietrich; Smetanska, Iryna

    2011-06-01

    Plant cell cultures provide a large potential for the production of secondary metabolites. Through the application of different physical and chemical cell stress factors, we investigated the production of the secondary metabolites in plant cell cultures. The effects of pulsed electric field (PEF) and ethephon on growth and secondary metabolism, particularly anthocyanins and phenolic acids synthesis, were investigated by using suspension culture of Vitis vinifera L. cv. Gamay Fréaux as a model system. Anthocyanins were measured by spectrophotometer and extracellular phenolic acids were determined by high-performance liquid chromatography. The compounds were identified by liquid chromatography-mass spectrometry and nuclear magnetic resonance. After the treatments with PEF and ethephon, the concentrations of anthocyanins and phenolic acids in cell culture were higher than in the control, without loss of biomass. The combination of PEF treatment and ethephon improved secondary metabolites formation. Production levels of extracellular phenolic acids, 3-O-glucosyl-resveratrol were increased by PEF and ethephon treatments. The results show that PEF induced a defense response of plant cells and may have altered the cell/membrane's dielectric properties. PEF, an external stimulus or stress, is proposed as a promising new abiotic elicitor for stimulating secondary metabolites biosynthesis in plant cell cultures.

  8. Electrophoresis in strong electric fields.

    Science.gov (United States)

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  9. Electrochemotherapy by pulsed electromagnetic field treatment (PEMF in mouse melanoma B16F10 in vivo

    Directory of Open Access Journals (Sweden)

    Kranjc Simona

    2016-03-01

    Full Text Available Pulsed electromagnetic field (PEMF induces pulsed electric field, which presumably increases membrane permeabilization of the exposed cells, similar to the conventional electroporation. Thus, contactless PEMF could represent a promising approach for drug delivery.

  10. Development of a linear piston-type pulse power electric generator for powering electric guns

    Science.gov (United States)

    Summerfield, Martin

    1993-01-01

    The development of a linear piston-type electric pulse-power generator capable of powering electric guns and EM (rail and coil) guns and ET guns, presently under development, is discussed. The pulse-power generator consists of a cylindrical armature pushed by gases from the combustion of fuel or propellant through an externally produced magnetic field. An arrangement of electrodes and connecting straps serves to extract current from the moving armature and to send it to an external load (the electric gun).

  11. Selection of surrogate bacteria in place of E. coli O157:H7 and Salmonella Typhimurium for pulsed electric field treatment of orange juice.

    Science.gov (United States)

    Gurtler, Joshua B; Rivera, Rebecca B; Zhang, Howard Q; Geveke, David J

    2010-04-30

    Pulsed electric field (PEF) technology has been used for the inactivation of microorganisms and to prevent flavor loss in liquid foods and beverages in place of thermal pasteurization. When used to pasteurize orange juice, PEF may prevent loss of volatile sensory attributes. Enterohemorrhagic E. coli O157:H7 (EHEC), two strains of Salmonella Typhimurium, and twenty strains of non-pathogenic bacteria were screened for inactivation in orange juice by PEF at 22 and 20kV/cm at 45 and 55 degrees C, respectively. Higher populations of both salmonellae were inactivated (2.81 and 3.54 log CFU/ml) at 55 degrees C, in comparison with the reduction of EHEC (2.22 log). When tested under the same conditions, inactivation of EHEC was slightly greater than that of a non-pathogenic E. coli (NPEC) ATCC 35218 (2.02 log). NPEC was further tested as a surrogate for EHEC by comparing inactivation kinetics at 45, 50 and 55 degrees C at field strengths of between 7.86 and 32.55kV/cm. Statistical comparison of revealed that EHEC and NPEC inactivation curves were homogeneous at outlet temperatures of 45 and 50 degrees C; however, EHEC was slightly more sensitive to PEF than the surrogate NPEC at 55 degrees C. The higher PEF resistance of non-pathogenic E. coli 35218 at 55 degrees C may provide a desirable margin of safety when used in pilot plant challenge studies in place of E. coli O157:H7.

  12. Application of pulsed electric field in the production of juice and extraction of bioactive compounds from blueberry fruits and their by-products.

    Science.gov (United States)

    Bobinaitė, Ramunė; Pataro, Gianpiero; Lamanauskas, Nerijus; Šatkauskas, Saulius; Viškelis, Pranas; Ferrari, Giovanna

    2015-09-01

    The influence of Pulsed Electric Field (PEF) pre-treatment of blueberry fruits (Vaccinium myrtillus L.), both on the extraction yield and antioxidant properties of juice obtained by pressing and on the on the recovery of bioactive compounds from berry by-products (press cake) by extraction with solvent, was investigated. PEF treatments carried out at field strengths of 1, 3, and 5 kV/cm and an energy input of 10 kJ/kg achieved a cell disintegration index (Z p ) of 0.70, 0.80, and 0.87, respectively. Mechanical pressing (1.32 bar for 8 min) of PEF-treated berries (1, 3, and 5 kV/cm at 10 kJ/kg) significantly increased the juice yield (+28 %) compared with the untreated sample. The juice obtained from PEF pre-treated berries also had a significantly higher total phenolic content (+43 %), total anthocyanin content (+60 %) and antioxidant activity (+31 %). However, PEF treatment intensity higher than 1 kV/cm did not significantly improve the quantitative or qualitative characteristics of the juice. Compared to the untreated sample, higher amounts of total phenolics (+63 %), total athocyanins (+78 %) and antioxidant activity (+65 %) were detected in the press cake extracts. PEF treatment of higher intensity resulted in better extractability of bioactive compounds from blueberry press cake. The results obtained from this study demonstrate the potential of PEF as a mild pre-treatment method to improve the efficiency of the industrial processing of berry fruits.

  13. Electron emission from La-doped Pb(Zr,Sn,Ti)O_3 anti-ferroelectrics by pulse electric field and the relevant physical mechanism

    Institute of Scientific and Technical Information of China (English)

    ZHANG LinLi; FENG YuJun; XU Zhuo; SHENG ZhaoXuan

    2009-01-01

    We investigate the characteristics of emission current waves of antiferroelectric cathode material lanthanum-doped lead zirconate stannate titanate (PLZST) triggered by pulse field, and analyze the relationship of the emission current waveforms with the extraction voltage. The close correlation between the triggering pulse polarity and emission current waveform observed evidences the relevant physical process of electron emission. We speculate that the primary emission may result from local phase transition and field emission in the vicinity of triple junctions, and the plasma formation may enhance the electron emission.

  14. The Effect of an Electric Field on Sensitivity of Primary Explosives

    Science.gov (United States)

    1977-06-01

    Pulsed electric field RD1333...EXPERIMENTAL Apparatus The parallel-plate, fixed-gap apparatus (Ref 6) was used for the electrostatic sensitivity measurements and the pulsed electric field experiments...through the chamber. Procedures 1. Pulsed Electric Field The parallel-plate geometry (Fig 2b) with an interelectrode gap of 0.19 mm was used for

  15. Isolated Attosecond Pulses using a Detuned Second-harmonic Field

    Energy Technology Data Exchange (ETDEWEB)

    Merdji, Hamed; /Saclay /SLAC, PULSE; Auguste, Thierry; Boutu, Willem; Caumes, J.-Pascal; Carre, Bertrand; /Saclay; Pfeifer, Thomas; Jullien, Aurelie; Neumark, Daniel M.; Leone, Stephen R.; /UC, Berkeley /LBL, Berkeley

    2007-11-07

    Calculations are presented for the generation of an isolated attosecond pulse in a multicycle two-color strong-field regime. We show that the recollision of the electron wave packet can be confined to half an optical cycle using pulses of up to 40 fs in duration. The scheme is proven to be efficient using two intense beams, one producing a strong field at {omega} and the other a strong field detuned from 2{omega}. The slight detuning {delta}{omega} of the second harmonic is used to break the symmetry of the electric field over many optical cycles and provides a coherent control for the formation of an isolated attosecond pulse.

  16. Design of Pulsed Strong Magnetic Fields Generator and Preliminary Application

    Institute of Scientific and Technical Information of China (English)

    WEN Jun; QU Xue-min; WANG Xi-gang; LONG Kai-ping

    2015-01-01

    Objective: This paper aims to designing a pulsed strong magnetic fields generator. Methods: A large value capacitor was used to store electric energy, coil was used for producing magnetic fields, main control, circuit control charge, sampling, discharge, etc. Results: The generator provided a pulsed magnetic field with the ampli-tude of intensity from 0.1-2 T and variable time interval of pulse from 4 s-1 min. It was not only to be operated easily but also performed reliably. Conclusion:The generator will be applied in special clinical diagnosis, therapy and other fields.

  17. Effect of environmental factors and cell physiological state on Pulsed Electric Fields resistance and repair capacity of various strains of Escherichia coli.

    Science.gov (United States)

    Somolinos, M; García, D; Mañas, P; Condón, S; Pagán, R

    2008-06-10

    The aim was to determine the resistance variation of four strains of Escherichia coli to Pulsed Electric Fields (PEF), the role of the sigma factor RpoS in PEF resistance, as well as the influence of several environmental factors and the cell physiological state on the PEF resistance and repair capacity. The rpoS null mutant, E. coli BJ4L1, exhibited decreased PEF resistance as compared with its wild-type parent, BJ4. W3110 and O157:H7 were the most PEF-resistant strains: whereas 2 and more than 3 Log10 cycles of BJ4 and BJ4L1 cells, respectively, were inactivated after 50 pulses at 35 kV/cm, only 0.5 Log10 cycle of inactivation of W3110 and O157:H7 was attained. A different pattern was observed and the resistance variation among strains was largely reduced, when selective recovery media were used. At exponential growth phase, the resistance of the four strains was lower, and more than 4 Log10 cycles of inactivation of all strains tested were attained at 30 kV/cm. Previous heat and cold shock treatments scarcely influenced cell PEF resistance. PEF survival increased with the reduction in water activity of the treatment medium to 0.94: the occurrence of sublethally injured cells was negligible, and less than 1 Log10 cycle of inactivation was attained at 35 kV/cm. PEF-treated cells were sensitive to a subsequent storage at pH 4.0 or in the presence of sorbic acid, attaining a final inactivation of 4-5 Log10 cycles after 24 hour-incubation. In conclusion, the work confirms the role of rpoS in PEF resistance. E. coli strains exhibit large differences in PEF resistance. These differences were less important when cells were recovered under selective conditions. Both resistance variation among strains and occurrence of sublethal damage were noticeably influenced by the environmental factors tested.

  18. Effects of ultraviolet irradiation, pulsed electric field, hot water dip and ethanol vapours treatment on keeping and sensory quality of mung bean (Vigna radiata L. Wilczek) sprouts.

    Science.gov (United States)

    Goyal, Ankit; Siddiqui, Saleem

    2014-10-01

    The objective of this research work was to evaluate the effects of UV- irradiation, pulsed electric field (PEF), hot water dip (HWD) and ethanol vapours on the quality and storage life of mung bean sprouts (Vigna radiata L. Wilczek). The sprouts were subjected to various treatments viz., UV-Irradiation (10 kJm(-2) in laminar flow chamber for 1 h), PEF (10,000 V for 10s), HWD (50 °C for 2 min) and ethanol vapours (1 h); and then stored in thermocol cups wrapped with perforated cling films at room (25 ± 1 °C) and low (7 ± 1 °C) temperature conditions. The sprouts were analyzed regularly at 24 h interval for sprout length, sprout weight, total soluble solids (TSS), titratable acidity, non-enzymatic browning, total plate count and overall acceptability. Sprout length and weight increased during storage. There was no significant effect of various treatments on sprout length and weight, except in ethanol treatment, where suppression was observed. HWD showed higher TSS and acidity than that of control. The least browning was observed in ethanol treatment. The total plate count was not significantly affected by various treatments. Overall acceptability under various treatments decreased during storage period both at room and low temperature. Hot water and ethanol vapour treated sprouts showed higher acceptability than other treatments. However, the acceptability scores for sprouts remained within the acceptable range (≥6) up to 72 h at room temperature and 120 h at low temperature conditions.

  19. 脉冲电场对丙酸乙醇酯化反应影响%Effect of pulse electric field on esterification of propionic acid and ethanol

    Institute of Scientific and Technical Information of China (English)

    林志荣; 曾新安; 于淑娟

    2013-01-01

    通过脉冲电场(PEF)对丙酸乙醇酯化反应的强化,研究了脉冲电场对丙酸乙酯含量、反应速率常数、活化能的影响采用气相色谱分析丙酸乙酯含量,结果表明,脉冲电场促进了酯化反应丙酸乙酯的含量和反应速率常数随着PEF场强的增加而增大;实验条件下的丙酸乙醇酯化反应为二级反应,当PEF场强为0、6.6、13.3、20.0kV/cm时,活化能分别为77.05、72.60、62.85、62.49k J/mol.%The effects of pulse electric field(PEF) on ethyl propionate concention,rate constant and activation energy were studied in this paper. The ethyl propionate concention was analyzed using a gas chromatography system. The results indicate that esterification could be promoted by PEF treatment under appropriate condition. The higher the PEF intensity applied,the higher the ethyl propionate concention and rate constant were. The reaction order was 2. When PEF intensity were 0,6.6,13.3,20.0 kV/cm,it was calculated that the activation energy for the esterification was 77.05,72.60,62.85,62.49 kJ/mol,respectively.

  20. Changes in polyphenol profiles and color composition of freshly fermented model wine due to pulsed electric field, enzymes and thermovinification pretreatments.

    Science.gov (United States)

    El Darra, Nada; Turk, Mohammad F; Ducasse, Marie-Agnès; Grimi, Nabil; Maroun, Richard G; Louka, Nicolas; Vorobiev, Eugène

    2016-03-01

    This work compares the effects of three pretreatments techniques: pulsed electric fields (PEFs), enzymes treatment (ET) and thermovinification (TV) on the improving of extraction of main phenolic compounds, color characteristics (L(∗)a(∗)b(∗)), and composition (copigmentation, non-discolored pigments) of freshly fermented model wine from Cabernet Sauvignon variety. The pretreatments produced differences in the wines, with the color of the freshly fermented model wine obtained from PEF and TV pretreated musts being the most different with an increase of 56% and 62%, respectively, compared to the control, while the color only increased by 22% for ET. At the end of the alcoholic fermentation, the contents of anthocyanins for all the pretreatments were not statistically different. However, for the content of total phenolics and total flavonols, PEF and TV were statistically different, but ET was not statistically different. The contents of flavonols in musts pretreated by PEF and TV were significantly higher comparing to the control. An increase of 48% and 97% was noted respectively, and only 4% for ET. A similar result was observed for the total phenolics with an increase by 18% and 32% respectively for PEF and TV, and only 3% for ET comparing to the control. The results suggest that the higher intensity and the difference of color composition between the control and pretreated freshly fermented model wines were not related only to a higher content of residual native polyphenols in these freshly fermented model wines. Other phenomena such as copigmentation and formation of derived pigments may be favored by these pretreatments.

  1. Nanosecond pulse electric field activation of platelet-rich plasma reduces myocardial infarct size and improves left ventricular mechanical function in the rabbit heart.

    Science.gov (United States)

    Hargrave, Barbara; Li, Francis

    2012-12-01

    In the current study, we used the novel, nonchemical method of nanosecond pulsed electric fields (nsPEF) to investigate the efficiency of a protocol involving the in vivo treatment of the ischemic and reperfused heart and heart cells in culture with platelet-rich plasma (PRP). Associated with the restoration of blood flow to the ischemic tissue is a phenomenon referred to as "ischemic reperfusion injury." Clinically a type of reperfusion injury occurs during coronary bypass surgery once blood perfusion to the heart is restarted. Although the restoration of oxygen to ischemic myocardial cells is critical for tissue survival, reperfusion causes myocardial oxidative stress, attributable in part to the increased production of reactive oxygen species (ROS). Enhanced ROS production is associated with mitochondrial damage. Adult female New Zealand white rabbits were anesthetized and a left thoracotomy performed to expose the heart. The distal segment of the left anterior descending coronary artery was occluded for 15 minutes and then released so reperfusion of the tissue could occur. PRP (.21 mg/heart) or saline was injected into the ischemic area of the myocardium. Mechanical function of the left ventricle was analyzed using a Millar catheter attached to a Micro-Med Analysis System. H9c2 cells in culture were treated with 1 mL of nsPEF activated PRP (1.05 mg/flask) for 24 hours before analysis for ROS production or mitochondrial depolarization damage). The left ventricle contracted and relaxed faster and infarct size was reduced in hearts treated with PRP compared with saline. ROS production and mitochondrial depolarization were reduced in H9c2 cells treated with PRP and stimulated with hydrogen peroxide. These results provide evidence that nsPEFs can successfully be used to prepare PRP and that the PRP is functional in heart protection possibly by reducing ROS generation and stabilizing the mitochondria of the ischemic/reperfused heart.

  2. Electric field controlled emulsion phase contactor

    Science.gov (United States)

    Scott, Timothy C.

    1995-01-01

    A system for contacting liquid phases comprising a column for transporting a liquid phase contacting system, the column having upper and lower regions. The upper region has a nozzle for introducing a dispersed phase and means for applying thereto a vertically oriented high intensity pulsed electric field. This electric field allows improved flow rates while shattering the dispersed phase into many micro-droplets upon exiting the nozzle to form a dispersion within a continuous phase. The lower region employs means for applying to the dispersed phase a horizontally oriented high intensity pulsed electric field so that the dispersed phase undergoes continuous coalescence and redispersion while being urged from side to side as it progresses through the system, increasing greatly the mass transfer opportunity.

  3. Electric-field-stimulated protein mechanics.

    Science.gov (United States)

    Hekstra, Doeke R; White, K Ian; Socolich, Michael A; Henning, Robert W; Šrajer, Vukica; Ranganathan, Rama

    2016-12-15

    The internal mechanics of proteins-the coordinated motions of amino acids and the pattern of forces constraining these motions-connects protein structure to function. Here we describe a new method combining the application of strong electric field pulses to protein crystals with time-resolved X-ray crystallography to observe conformational changes in spatial and temporal detail. Using a human PDZ domain (LNX2(PDZ2)) as a model system, we show that protein crystals tolerate electric field pulses strong enough to drive concerted motions on the sub-microsecond timescale. The induced motions are subtle, involve diverse physical mechanisms, and occur throughout the protein structure. The global pattern of electric-field-induced motions is consistent with both local and allosteric conformational changes naturally induced by ligand binding, including at conserved functional sites in the PDZ domain family. This work lays the foundation for comprehensive experimental study of the mechanical basis of protein function.

  4. Comparative studies on extraction of laminarin by high voltage pulsed electric fields and traditional method%高压脉冲电场和传统热水法提取海带多糖的比较研究

    Institute of Scientific and Technical Information of China (English)

    刘航; 冯立强; 刘兴江

    2016-01-01

    Orthogonal tests are carried out to determine optimal laminarin extraction technologies by the high voltage pulsed electric fields and the traditional hot water method.The mechanism of the high voltage pulsed electric fields is preliminarily discussed.The optimal conditions of traditional method are:1∶50 of material-liquid ratio,60 ℃ of extraction temperature and 40 minutes of extraction time.The optimal conditions of high voltage pulsed electric fields are:1 ∶ 30 of material-liquid ratio,20 minutes of pulse time,10 kV of electric field intensity and 50 Hz of pulse frequency.Compared with traditional hot water extraction method,the extraction time is shortened by 50% and the extraction ratio is increased by 45% for high voltage pulsed electric field method.%利用正交试验确定了高压电脉冲电场和传统热水法提取海带多糖的方法的最佳工艺,并对2种工艺进行了比较,初步探讨高压脉冲的作用机理.结果表明,传统热水法提取海带多糖的最佳工艺为:海带粉与去离子水的料液比为1∶50,提取温度为60℃,提取时间为40 min.高压脉冲电场的最佳工艺为:海带粉与去离子水的料液比为1∶30,脉冲时间为20 min,脉冲电压为10 kV,脉冲频率为50 Hz.提取时间仅为传统热水法时间的1/2,海带多糖提取率比传统热水法提高45%.

  5. 纳秒脉冲电场灭菌对舒心糖浆质量影响的初步研究%The Preliminary Study of Nanosecond Pulsed Electric Field Sterilization on Quality of Shuxin Syrup

    Institute of Scientific and Technical Information of China (English)

    李玉美; 陈新梅; 徐溢明; 葛陈元; 樊梦萦; 王宇

    2015-01-01

    To discuss effect of nanosecond pulsed electric field sterilization on shuxin syrup' s quality of varia-tion. According to character, density, pH ,content of active ingredient-Astragaloside IV ,shuxin syrup sterilized by nanosecond pulsed electric field was examined quality of variation. By comparison ,shuxin syrup had little obvious var-iation on character density pH content of Astragaloside IV before and after sterilization. Nanosecond pulsed electric field sterilization has no effect on the quality of shuxin syrup,and it can be made as a new way of sterilization to be studied in further.%探讨纳秒脉冲电场灭菌对舒心糖浆质量变化的影响作用. 以性状、密度、pH值、有效成分黄芪甲苷含量为质量评价指标,考察纳秒脉冲电场灭菌对舒心糖浆的影响作用. 舒心糖浆在经纳秒脉冲电场灭菌前后在外观、密度、pH值、黄芪甲苷含量均无明显变化. 纳秒脉冲电场灭菌对舒心糖浆质量无影响,可作为一种新型灭菌方式来继续深入研究.

  6. Application of pulsed electric fields in fruit and vegetable juice processing%高压脉冲电场技术及其在果蔬汁加工过程中的应用进展

    Institute of Scientific and Technical Information of China (English)

    崔素芬; 廖芬; 张娥珍; 黄茂康; 孙健; 何全光

    2012-01-01

    高压脉冲电场技术(pulsed electric field,PEF)作为非热处理技术之一,在杀菌钝酶、活性物质提取、保持食品原汁原味等方面显示了很大的优势,近些年来成为食品科学与工程研究的热点。文章就国内外关于PEF技术及其在果蔬汁生产过程中的应用研究进行综述,以期为该技术应用于果蔬汁工业生产提供参考。%As one of the non-thermal processing technologies,the pulsed electric field(PEF) technology has been a hot research topic in the area of food science and engineering in recent years.It shows great advantages on the sterilization,enzymic inactivation,active substances extraction and keeping greenness,nutrition and sanitation of food.The pulsed electric field(PEF) technology and its latest application in fruit and vegetable juice industry were reviewed,which would be helpful to the juice industrial production of using this technology.

  7. Design of sewage treatment system based on high-voltage pulsed electric field technology%基于高压脉冲电场技术的污水处理系统研究设计

    Institute of Scientific and Technical Information of China (English)

    李唐; 王亚伟; 赵振良; 尤丽华

    2013-01-01

    针对污水处理厂剩余污泥含水率高,达到70%-80%,不利于进一步处理的问题,根据污水成分及其处理工艺特点,提出了一种基于高压脉冲电场技术的污水处理的方法.本文从理论上系统地阐述了高压脉冲电场处理装置的研制,设计了低成本高压脉冲电源,最高电压10 kV,最大电流50A,并且能方便的调节电场参数.%Contrary to the problem that the high moisture content of the excess sludge of the sewage treatment plant, up to 70% to 80% , the paper proposed a sewage treatment method based on the high-voltage pulse electric field (HPEF) technology, according to the composition of sewage and the feature of its treatment technology.The paper systematically expounded of how to design a pulsed electric field theoretically,and design a low-cost high-voltage pulse power supply with the peak impulse voltage 10 kV and impulse current to 50 A, which also can easily adjust the electric field parameters.

  8. Nanosecond electric pulses modulate skeletal muscle calcium dynamics and contraction

    Science.gov (United States)

    Valdez, Chris; Jirjis, Michael B.; Roth, Caleb C.; Barnes, Ronald A.; Ibey, Bennett L.

    2017-02-01

    Irreversible electroporation therapy is utilized to remove cancerous tissues thru the delivery of rapid (250Hz) and high voltage (V) (1,500V/cm) electric pulses across microsecond durations. Clinical research demonstrated that bipolar (BP) high voltage microsecond pulses opposed to monophasic waveforms relieve muscle contraction during electroporation treatment. Our group along with others discovered that nanosecond electric pulses (nsEP) can activate second messenger cascades, induce cytoskeletal rearrangement, and depending on the nsEP duration and frequency, initiate apoptotic pathways. Of high interest across in vivo and in vitro applications, is how nsEP affects muscle physiology, and if nuances exist in comparison to longer duration electroporation applications. To this end, we exposed mature skeletal muscle cells to monopolar (MP) and BP nsEP stimulation across a wide range of electric field amplitudes (1-20 kV/cm). From live confocal microscopy, we simultaneously monitored intracellular calcium dynamics along with nsEP-induced muscle movement on a single cell level. In addition, we also evaluated membrane permeability with Yo-PRO-1 and Propidium Iodide (PI) across various nsEP parameters. The results from our findings suggest that skeletal muscle calcium dynamics, and nsEP-induced contraction exhibit exclusive responses to both MP and BP nsEP exposure. Overall the results suggest in vivo nsEP application may elicit unique physiology and field applications compared to longer pulse duration electroporation.

  9. The Effect of Millisecond Pulsed Electric Fields (msPEF) on Intracellular Drug Transport with Negatively Charged Large Nanocarriers Made of Solid Lipid Nanoparticles (SLN): In Vitro Study.

    Science.gov (United States)

    Kulbacka, Julita; Pucek, Agata; Wilk, Kazimiera Anna; Dubińska-Magiera, Magda; Rossowska, Joanna; Kulbacki, Marek; Kotulska, Małgorzata

    2016-10-01

    Drug delivery technology is still a dynamically developing field of medicine. The main direction in nanotechnology research (nanocarriers, nanovehicles, etc.) is efficient drug delivery to target cells with simultaneous drug reduction concentration. However, nanotechnology trends in reducing the carrier sizes to several nanometers limit the volume of the loaded substance and may pose a danger of uncontrolled access into the cells. On the other hand, nanoparticles larger than 200 nm in diameter have difficulties to undergo rapid diffusional transport through cell membranes. The main advantage of large nanoparticles is higher drug encapsulation efficiency and the ability to deliver a wider array of drugs. Our present study contributes a new approach with large Tween 80 solid lipid nanoparticles SLN (i.e., hydrodynamic GM-SLN-glycerol monostearate, GM, as the lipid and ATO5-SLNs-glyceryl palmitostearate, ATO5, as the lipid) with diameters DH of 379.4 nm and 547 nm, respectively. They are used as drug carriers alone and in combination with electroporation (EP) induced by millisecond pulsed electric fields. We evaluate if EP can support the transport of large nanocarriers into cells. The study was performed with two cell lines: human colon adenocarcinoma LoVo and hamster ovarian fibroblastoid CHO-K1 with coumarin 6 (C6) as a fluorescent marker for encapsulation. The biological safety of the potential treatment procedure was evaluated with cell viability after their exposure to nanoparticles and EP. The EP efficacy was evaluated by FACS method. The impact on intracellular structure organization of cytoskeleton was visualized by CLSM method with alpha-actin and beta-tubulin. The obtained results indicate low cytotoxicity of both carrier types, free and loaded with C6. The evaluation of cytoskeleton proteins indicated no intracellular structure damage. The intracellular uptake and accumulation show that SLNs do not support transport of C6 coumarin. Only application of

  10. High Pulsed Electric Field Experimental Study on Effect of Fruits and Vegetables Dielectric Characteristics%高压脉冲电场对果蔬介电特性影响的试验研究

    Institute of Scientific and Technical Information of China (English)

    马飞宇; 郭玉明

    2013-01-01

    高压脉冲电场作为一种非热加工技术,以其特有的优点成为近年来的研究热点,用于果蔬冻干预处理可明显地提高脱水速率,但在运用果蔬介电特性表达冻干过程水分运移规律时需研究电场参数对果蔬介电特性的影响.以苹果为试材,对苹果在高压脉冲电场预频率为1000 Hz时进行预处理,测量不同脉冲电压、脉冲频率对苹果的等效电容、等效阻抗等介电特性的影响,运用SAS软件分析获得等效电容、等效阻抗的数学模型,脉冲电压、频率与介电特性的三维关系图.结果表明,三者的数学模型及三维图均显示果蔬的介电特性随脉冲电压和脉冲频率的增大而减小,且呈线性函数关系;将高压脉冲预处理后的苹果进行干燥,运用响应面设计法,获得高压脉冲电场预处理的优化工艺参数.结果表明,高压脉冲电场预处理果蔬的最优工艺参数组合是脉冲电压为1480 V,脉冲频率为88 Hz,脉冲个数为46个.%High-voltage pulsed electric field become the research hot topic due to its peculiar advantages as one of the non-thermal technologies in recent years,which could be used for the pre-treatment of the freeze drying process and could improve the dehydration rate of fruits and vegetables.During this process,the effects of electric parameters on dielectric characteristics of fruit and vegetable should be well studied.As research material,apples were pre-treated with the high-voltage pulsed electric field of the frequency at 1000 Hz and the effect of pulse voltage,pulse frequency on apple's equivalent capacitance and equivalent impedance were measured.SAS software was used to analyze the mathematical models developed from the data of the equivalent capacitance,equivalent impedance and the three-dimensional figure of pulse voltage,frequency and the dielectric properties.The results showed that dielectric characteristics of fruits and vegetables were decreased with the

  11. Nanosecond electric pulses trigger actin responses in plant cells.

    Science.gov (United States)

    Berghöfer, Thomas; Eing, Christian; Flickinger, Bianca; Hohenberger, Petra; Wegner, Lars H; Frey, Wolfgang; Nick, Peter

    2009-09-25

    We have analyzed the cellular effects of nanosecond pulsed electrical fields on plant cells using fluorescently tagged marker lines in the tobacco cell line BY-2 and confocal laser scanning microscopy. We observe a disintegration of the cytoskeleton in the cell cortex, followed by contraction of actin filaments towards the nucleus, and disintegration of the nuclear envelope. These responses are accompanied by irreversible permeabilization of the plasma membrane manifest as uptake of Trypan Blue. By pretreatment with the actin-stabilizing drug phalloidin, the detachment of transvacuolar actin from the cell periphery can be suppressed, and this treatment can also suppress the irreversible perforation of the plasma membrane. We discuss these findings in terms of a model, where nanosecond pulsed electric fields trigger actin responses that are key events in the plant-specific form of programmed cell death.

  12. Optimal Parameters of High Pulse Electric Field in Oil Demulsion%高压脉冲电场中乳化油最佳破乳电场参数

    Institute of Scientific and Technical Information of China (English)

    龚海峰; 杨智君; 彭烨; 张贤明

    2015-01-01

    Reasonable electric field parameters were the key premise to ensure the emulsion oil’s efficient demulsification and dewatering under the high voltage pulse electric field, however the study of the theory about the electric field parameters was rarely reported. By establishing the vibration kinetics model of emulsion oil droplet under the high voltage pulse electric field, the swing-frequency characteristics of droplet vibration were studied, and then the resonance frequency and resonance amplitude of droplet were obtained. On the basis of study above, by combining with the condition of droplet’s maximum stable tensile deformation and using the method of drawing, the electric field frequency and strength values of emulsion oil’s optimal demulsification were then calculated with physical parameters of the system. The experimental results show that, emulsion oil system’s optimal demulsification electric field parameters obtained from calculation can enhance the efficient coalescence of the droplets in emulsion. Therefore, the high voltage pulse electric field parameters of emulsion oil’s optimal demulsification, determined by nonlinear vibration kinetics, are reasonable and reliable.%合理的电场参数是确保高压脉冲电场实现乳化油液高效破乳脱水的重要前提,目前关于电场参数的理论研究鲜有报道。通过建立乳化油液滴在高压脉冲电场中的振动动力学模型,研究液滴振动幅频特性,得到液滴共振频率及共振振幅。在此基础上,根据乳化油系统物性参数,结合液滴最大稳态拉伸变形条件,利用作图法可计算出乳化油最佳破乳电场频率与电场强度的值。实验结果表明,计算得到的最佳破乳电场参数能够实现乳化液滴高效结聚。因此,利用非线性振动动力学确定的乳化油最佳破乳电场参数是合理可靠的。

  13. What Are Electric and Magnetic Fields? (EMF)

    Science.gov (United States)

    ... take for granted. What are electric and magnetic fields? Electric and magnetic fields (EMF) are invisible lines of ... humans. AC electric power produces electric and magnetic fields that create weak electric currents in humans. Being exposed to some kinds ...

  14. 基于PLC的脉冲电场控制系统的研制%Research on the control system of pulse electric field based on PLC

    Institute of Scientific and Technical Information of China (English)

    李伟光; 聂小军

    2012-01-01

    PLC is a control unit which is widely used in industry with the characteristics of simple pro- gramming,powerful controlling function and reliable runningWhile touching screen is a human machine interface applied commonly in industry with characteristics of visualized interface,simple operation and high working stability so that man-machine delivery is achievedAn automatic control system based on PLC for pulse electric field was discussedAt first,the machine working process was stated and the function plan was made for this controlling system based on the process.Then the hardware was designed based on the controlling function with PLC being used as the controlling kerneLMoreover ,the touching screen was used to realize the good information exchange between the machine and humanAt the end,the operation interface of touching screen and the control procedure of PLC were designedThe whole system is simple in structure,high in working stability and convenient in adjustment that can meet the operating requirement well%PLC是工业上广泛使用的控制单元,具有编程简单、功能强大、运行可靠等优点.而触摸屏是工业上常用的人机界面,具有界面直观、操作方便、工作稳定等特点,能较好地实现人机交付的功能.主要探讨了一种基于PLC的自动控制系统,用于对脉冲电场的自动控制.首先,描述了设备的工作过程,根据工作过程对设备的控制系统进行了详细的功能规划.然后,结合系统要实现的功能设计了系统的硬件结构,选择PLC作为系统的控制核心,同时选择触摸屏与PLC配合,实现良好的人机交付.最后,设计了触摸屏的操作界面和PLC的控制程序.整个系统结构简单,工作可靠,调整方便,能较好地满足使用要求.

  15. Schwinger effect in inhomogeneous electric fields

    CERN Document Server

    Hebenstreit, Florian

    2011-01-01

    The vacuum of quantum electrodynamics is unstable against the formation of many-body states in the presence of an external electric field, manifesting itself as the creation of electron-positron pairs (Schwinger effect). This effect has been a long-standing but still unobserved prediction as the generation of the required field strengths has not been feasible so far. However, due to the advent of a new generation of high-intensity laser systems such as the European XFEL or the Extreme Light Infrastructure (ELI), this effect might eventually become observable within the next decades. Based on the equal-time Wigner formalism, various aspects of the Schwinger effect in electric fields showing both temporal and spatial variations are investigated. Regarding the Schwinger effect in time-dependent electric fields, analytic expressions for the equal-time Wigner function in the presence of a static as well as a pulsed electric field are derived. Moreover, the pair creation process in the presence of a pulsed electric...

  16. 高压脉冲电场设备及其在食品非热处理中的应用%Pulsed Electric Fields System and Its Application in Non-thermal Food Processing

    Institute of Scientific and Technical Information of China (English)

    张若兵; 陈杰; 肖健夫; 廖小军; 王黎明; 关志成

    2011-01-01

    为较全面了解高压脉冲电场(PEF)食品非热加工技术,总结了清华大学在PEF上的开发和应用研究,对PEF技术的理论研究和工业化发展现状进行了综述.首先分析了清华大学4代高压脉冲电场系统的电源结构拓扑和性能以及处理室的结构特性,其次对相关系统在液态食品处理领域的应用研究进行了总结介绍.研究结果表明,经过近10 a的努力,清华大学所设计开发研制的高压脉冲电场果汁非热处理系统可满足实验室应用需求,并正向工业中试规模应用努力.%In order to comprehensively understand PEF, we reviewed the investigation of pulsed electric fields (PEF) by focusing on the development and application of pulsed electric field systems at Tsinghua University, and summa rized four generations of pulsed electric field systems developed by Graduate School at Shenzhen, Tsinghua Universi ty. Moreover, we analyzed the electrode configuration and topology of typical pulsed power generators and relevant application researches of these systems in food processing. The research results show that, after ten years develop ment, the laboratory scaled THU -PEF series PEF treatment system designed for R&-D applications has met the demands of research and the pilot plant scaled system has been studied recently.

  17. 高压脉冲电场技术在杨梅保鲜中的应用研究%Study on the application of high pulse electric field technology in preserving Myrica rubra fruits

    Institute of Scientific and Technical Information of China (English)

    张雯; 韩其国; 朱英俊; 郑兴华; 何晶; 刘珂舟; 杨勇

    2012-01-01

    高压脉冲电场灭菌技术是国际上研究较为热门的非热灭菌技术之一。实验目的是探讨高压脉冲电场技术用于杨梅保鲜的可行性。工作电压100kV的高压脉冲电场由本实验室研制,将新鲜杨梅置于高压脉冲电场产品处理室中,设置不同电场参数(脉宽、频率、电场作用时间)对杨梅进行处理,通过分析对照组和处理组杨梅的pH变化以及气味、色泽等感官指标的变化来验证高压脉冲电场对杨梅的保鲜效果。结果显示影响杨梅保鲜的最主要因素是电场脉冲宽度,最佳的参数组合是脉宽10μs,频率80Hz,作用时间10s。结论:高压脉冲电场对杨梅保鲜有一定的效果。%High pulse electric field(HPEF) is a highly developing non-thermal sterilization technique in recent years. The aim was to investigate the feasibility of HPEF technique on keeping Myrica rubra fruits fresh.Samples of Myrica rubra fruits were put in the HPEF operate chamber, and then processed by setting different electric field parameters.By analyzing the changes of pH value, and sensory indexes such as smell and colour between the control group and dealing groups,the effect of Myrica rubra preservation by high pulse electric field could be invistigated.Results showed that:there was significant difference in pH value between control group and dealing groups;among the parameters ( pulse width, frequency and effect time) ,the most influencing factor to keep Myrica rubra fruits fresh was the pulse width ;the optimal parameter combination was pulse width for 10μs with frequency for 80Hz, and effect time for 10s. The results indicated that it was feasible by using high pulse electric field technology to keep Myrica rubra fruits fresh.

  18. The effect of high frequency steep pulsed electric fields on in vitro and in vivo antitumor efficiency of ovarian cancer cell line skov3 and potential use in electrochemotherapy

    Directory of Open Access Journals (Sweden)

    Zheng Fei-Yun

    2009-04-01

    Full Text Available Abstract Background Patients received electrochemotherapy often associated with unpleasant sensations mainly result from low-frequency electric pulse induced muscle contractions. Increasing the repetition frequency of electric pulse can reduce unpleasant sensations. However, due to the specificity of SPEF, frequency related antitumor efficiency need to be further clarified. The aim of this study was to compare in vitro cytotoxic and in vivo antitumor effect on ovarian cancer cell line SKOV3 by SPEF with different repetition frequencies. Explore potential benefits of using high frequency SPEF in order to be exploitable in electrochemotherapy. Methods For in vitro experiment, SKOV3 cell suspensions were exposed to SPEF with gradient increased frequencies (1, 60, 1 000, 5 000 Hz and electric field intensity (50, 100, 150, 200, 250, 300, 350, 400 V/cm respectively. For in vivo test, SKOV3 subcutaneous implanted tumor in BALB/c nude mice (nu/nu were exposure to SPEF with gradient increased frequencies (1, 60, 1 000, 5 000 Hz and fixed electric field intensity (250 V/cm (7 mice for each frequency and 7 for control. Antitumor efficiency was performed by in vitro cytotoxic assay and in vivo tumor growth inhibition rate, supplemented by histological and TEM observations. Data were analyzed using one-way ANOVA followed by the comparisons of multiple groups. Results SPEF with a given frequency and appropriate electric field intensity could achieve similar cytotoxicity until reached a plateau of maximum cytotoxicity (approx. 100%. SPEF with different frequencies had significant antitumor efficiency in comparison to the control group (P 0.05. Histological and TEM observations demonstrated obvious cell damages in response to SPEF exposure. Furthermore, SPEF with 5 kHz could induce apoptosis under TEM observations both in vitro and in vivo. Conclusion SPEF with high frequency could also achieve similar antitumor efficiency which can be used to reduce

  19. Pulsed beams as field probes for precision measurement

    OpenAIRE

    Hudson, J. J.; Ashworth, H. T.; Kara, D. M.; Tarbutt, M. R.; Sauer, B.E.; Hinds, E. A.

    2007-01-01

    We describe a technique for mapping the spatial variation of static electric, static magnetic, and rf magnetic fields using a pulsed atomic or molecular beam. The method is demonstrated using a beam designed to measure the electric dipole moment of the electron. We present maps of the interaction region, showing sensitivity to (i) electric field variation of 1.5 V/cm at 3.3 kV/cm with a spatial resolution of 15 mm; (ii) magnetic field variation of 5 nT with 25 mm resolution; (iii) radio-frequ...

  20. Experimental Investigation of Integrated Optical Intensive Impulse Electric Field Sensors

    Institute of Scientific and Technical Information of China (English)

    SUN Bao; CHEN Fu-Shen

    2009-01-01

    We design and fabricate an integrated optical electric field sensor with segmented electrode for intensive im-pulse electric field measurement. The integrated optical sensor is based on a Mach-Zehnder interferometer with segmented electrodes. The output/input character of the sensing system is analysed and measured. The max-imal detectable electric field range (-75 kV/m to 245 kV/m) is obtained by analysing the results. As a result, the integrated optics electric field sensing system is suitable for transient intensive electric field measurement investigation.

  1. Hemorrhage control by microsecond electrical pulses

    Science.gov (United States)

    Mandel, Yossi; Manivanh, Richard; Dalal, Roopa; Huie, Phil; Wang, Jenny; Brinton, Mark; Palanker, Daniel

    2013-02-01

    Non-compressible hemorrhages are the most common preventable cause of death on battlefield or in civilian traumatic injuries. We report the use of sub-millisecond pulses of electric current to induce rapid constriction in femoral and mesenteric arteries and veins in rats. Extent of vascular constriction could be modulated by pulse duration, amplitude and repetition rate. Electrically-induced vasoconstriction could be maintained at steady level until the end of stimulation, and blood vessels dilated back to their original size within a few minutes after the end of stimulation. At higher settings, a blood clotting could be introduced, leading to complete and permanent occlusion of the vessels. The latter regime dramatically decreased the bleeding rate in the injured femoral and mesenteric arteries, with a complete hemorrhage arrest achieved within seconds. The average blood loss from the treated femoral artery was about 7 times less than that of a non-treated control. This new treatment modality offers a promising approach to non-damaging control of bleeding during surgery, and to efficient hemorrhage arrest in trauma patients.

  2. PZT95/5陶瓷电致失效机理研究%Failure mechanism of PZT 95/5 under direct current and pulsed electric field

    Institute of Scientific and Technical Information of China (English)

    张福平; 杜金梅; 刘雨生; 刘艺; 刘高旻; 贺红亮

    2011-01-01

    The failure mechanism of PZT 95/5 under direct current and pulsed electric field is studied by experiment and theoretical analysis in this paper. The electrothermal coupled failure is the key mode when the PZT 95/5 is subjected to direct current. But when the pulsed electric field is applied to the PZT 95/5, the resonance effect and the relation between energy and frequency being considered, the vibrant energy shifts to high frequency and the possibility of electromechanical-coupled failure is increased with decreasing pulse duration. When the pulse duration is increased, the failure behavior transfers gradually from mechanical coupled with electric failure to direct current failure mode.%对PZT 95/5陶瓷在直流电场、脉冲方波电场以及半正弦波电场作用下的失效机理进行了理论和实验分析.结果表明:在直流作用下,其失效机理以热-电耦合失效为主;而在脉冲电场作用下,考虑振动冲击效应以及相关的力谱分布,脉宽越短,能量向高频偏移,越可能发生力-电耦合失效;当脉宽增加,PZT 95/5陶瓷失效机理将从力-电耦合失效逐步转变成直流失效模式.

  3. Direct sampling of electric-field vacuum fluctuations

    National Research Council Canada - National Science Library

    Riek, C; Seletskiy, D V; Moskalenko, A S; Schmidt, J F; Krauspe, P; Eckart, S; Eggert, S; Burkard, G; Leitenstorfer, A

    2015-01-01

    .... The ground-state electric-field variance is inversely proportional to the four-dimensional space-time volume, which we sampled electro-optically with tightly focused laser pulses lasting a few femtoseconds...

  4. High field rf superconductivity: to pulse or not to pulse

    Energy Technology Data Exchange (ETDEWEB)

    Campisi, I.E.

    1984-10-01

    Experimental data on the behavior of superconductors under the application of rf fields of amplitude comparable to their critical fields are sporadic and not always consistent. In many cases the field level at which breakdown in superconducting rf cavities should be expected has not been clearly established. Tests conducted with very short (approx. 1 ..mu..s) rf pulses indicate that in this mode of operation fields close to the critical values can be consistently reached in superconducting cavities without breakdown. The advantages and disadvantages of the pulsed method are discussed compared to those of the more standard continuous wave (cw) systems. 60 references.

  5. Molecular orientation via a dynamically induced pulse-train: Wave packet dynamics of NaI in a static electric field

    DEFF Research Database (Denmark)

    Marquetand, P.; Materny, A.; Henriksen, Niels Engholm

    2004-01-01

    We regard the rovibrational wave packet dynamics of NaI in a static electric field after femtosecond excitation to its first electronically excited state. The following quasibound nuclear wave packet motion is accompanied by a bonding situation changing from covalent to ionic. At times when...... the charge separation is present, i.e., when the bond-length is large, a strong dipole moment exists and rotational excitation takes place. Upon bond contraction, the then covalently bound molecule does not experience the external field. This scenario repeats itself periodically. Thus, the vibrational...

  6. 脉冲电场促进宫颈癌HeLa细胞摄取光敏剂的实验研究%Pulsed Electric Fields Enhancing Uptake of Photosensitizer into HeLa Cells: An Experimental Study

    Institute of Scientific and Technical Information of China (English)

    刘世东; 郑飞云; 杨孝军; 韦伟

    2011-01-01

    目的 探讨脉冲电场对人宫颈癌HeLa细胞摄取光敏剂"二氢卟吩E6"的促进作用.方法 以人宫颈癌HeLa细胞为研究对象,通过细胞毒性实验比较单独或联合应用脉冲电场与光动力治疗时细胞的杀伤效应的差异;通过激光共聚焦显微镜半定量与流式细胞术定量观察细胞内荧光物质的强度.结果 脉冲电场联合光动力治疗提高了细胞的杀伤效率,强于单纯光动力治疗组;激光共聚焦显微镜半定量观察可见,脉冲电场联合光动力治疗组细胞内的荧光亮度明显高于单纯光动力治疗组;流式细胞术定量检测证实了脉冲电场联合光动力治疗,显著增加HeLa细胞对光敏剂的摄取(P<0.001).结论 脉冲电场显著促进宫颈癌HeLa细胞摄取光敏剂,可有效增加光动力治疗的效率,减少其副作用.%Objective To investigate the promotion of pulsed electric fields in enhancement of the uptake of photosensitizer " chlorin E6" into human cervix cancer HeLa cells. Methods HeLa cells were given with pulsed electric fields or/and photodynamic therapy to compare the difference of cell killing effects by cytotoxicity test; the intensity of fluorescent substances was observed semi - quantitatively by confocal laser scanning microscopy ( CLSM ) and quantitatively by flow cytometry. Results Pulsed electric fields with photodynamic therapy improved cell killing effects, stronger than single photodynamic therapy.CLSM semi - quantitative analysis showed that fluorescence intensity of pulsed electric field comhined with photodynamic therapy was significantly higher than that of single photodynamic therapy. Flow cytometry quantitative analysis showed that pulsed electric field with photodynamic therapy enhanced the uptake of photosensitizer into HeLa cells ( P < 0. 001 ) . Conclusion Pulsed electric field , enhancing significantly the uptake of photosensitizer into HeLa cells. can mcrease effectively the efficiency of photodynamic

  7. Pulsed electrical breakdown of a void-filled dielectric

    Science.gov (United States)

    Anderson, R. A.; Lagasse, R. R.; Schroeder, J. L.

    2002-05-01

    We report breakdown strengths in a void-filled dielectric material, epoxy containing 48 vol % hollow glass microballoon filler, which is stressed with unipolar voltage pulses of the order of 10 μs duration. The microballoon voids had mean diameters of approximately 40 μm and contained SO2 gas at roughly 30% atmospheric pressure. This void-filled material displays good dielectric strength (of the order of 100 kV mm-1) under these short-pulse test conditions. Results from a variety of electrode geometries are reported, including arrangements in which the electric stress is highly nonuniform. Conventional breakdown criteria based on mean or peak electric stress do not account for these data. A statistics-based predictive breakdown model is developed, in which the dielectric is divided into independent, microballoon-sized "discharge cells" and the spontaneous discharge of a single cell is presumed to launch full breakdown of the composite. We obtain two empirical parameters, the mean and standard deviation of the spontaneous discharge field, by fitting breakdown data from two electrode geometries having roughly uniform fields but with greatly differing volumes of electrically stressed material. This model accounts for many aspects of our data, including the inherent statistical scatter and the dependence on the stressed volume, and it provides informative predictions with electrode geometries giving highly nonuniform fields. Issues related to computational spatial resolution and cutoff distance are also discussed.

  8. Angular Spectrum Simulation of Pulsed Ultrasound Fields

    DEFF Research Database (Denmark)

    Du, Yigang; Jensen, Henrik; Jensen, Jørgen Arendt

    2009-01-01

    The optimization of non-linear ultrasound imaging should in a first step be based on simulation, as this makes parameter studies considerably easier than making transducer prototypes. Such a simulation program should be capable of simulating non-linear pulsed fields for arbitrary transducer...... geometries for any kind of focusing and apodization. The Angular Spectrum Approach (ASA) is capable of simulating monochromatic non-linear acoustic wave propagation. However, for ultrasound imaging the time response of each specific point in space is required, and a pulsed ASA simulation with multi temporal....... The RMS error of the pulses for all points in the simulated plane is 10.9%. The good agreement between ASA and Field II simulation for the pulsed ultrasound fields obtained in this paper makes it possible to expand Field II to non-linear pulsed fields....

  9. Magnetization reversal in ultrashort magnetic field pulses

    CERN Document Server

    Bauer, M; Fassbender, J; Hillebrands, B

    2000-01-01

    We report the switching properties of a thin magnetic film subject to an ultrashort, laterally localized magnetic field pulse, obtained by numerical investigations. The magnetization distribution in the film is calculated on a grid assuming Stoner-like coherent rotation within the grid square size. Perpendicularly and in-plane magnetized films exhibit a magnetization reversal due to a 4 ps magnetic field pulse. Outside the central region the pulse duration is short compared to the precession period. In this area the evolution of the magnetization during the field pulse does not depend strongly on magnetic damping and/or pulse shape. However, the final magnetization distribution is affected by the magnetic damping. Although the pulse duration is short compared to the precession period, the time needed for the relaxation of the magnetization to the equilibrium state is rather large. The influence of the different magnetic anisotropy contributions and the magnetic damping parameter enters into the magnetization ...

  10. Effect of pulsed electric field treatment on Maillard reaction of reducing sugars with glutamic acid-Na%脉冲电场对还原糖-谷氨酸钠体系美拉德反应的影响

    Institute of Scientific and Technical Information of China (English)

    陈刚; 于淑娟

    2011-01-01

    主要研究了脉冲电场对于不同还原糖-谷氨酸钠溶液的pH、中间产物、褐变、还原糖含量以及抗氧化活性的影响.结果显示:脉冲电场处理条件为场强4kV/cm,时间1.88ms,得到果糖-甘氨酸钠体系在294nm和420nm的吸光值从0分别增加到1.71和0.07,同时,抗氧化活性增加10.96%,果糖含量减少55%.气质分析表明,经脉冲电场处理可以引发葡萄糖、蔗糖、麦芽糖和乳糖分别与谷氨酸钠体系的美拉德反应,产物包括苯的衍生物、酰胺及醛,但是在果糖-谷氨酸钠反应液中发现了丙烷、醋酸和丁内酯.研究证明,脉冲电场是一种提高还原糖-谷氨酸钠体系美拉德反应的有效方法.%Effects of pulsed electric field on pH, intermediate products, browning, reducing sugar content, and antioxidant activity of different reducing sugar-glutamic acid-Na solutions were examined.Results showed that the pulsed electric field treatment at the intensity of 4kV/cm for 1.88ms resulted in the pronounced increases of the fructose- glutamic acid - Na solution' s absorbance at 294nm and 420nm and the antioxidant activity from approximately 0 to 1.71,0.07 and 10.96%,respectively.At the same time,55% reduction in fructose was observed. Gas Chromatography/Mass Spectrum analysis showed that the pulsed electric field treatment induced a Maillard reaction in the glucose-,sucrose-,maltose-and lactose-glutamic acid-Na model systems producing substances including benzene derivatives, acylamide or aldehydes, while, propane, acetic acid, butyrolactone were found in fructose-glutamic acid-Na reacted solution.This study indicated that pulsed electric field could potentially be employed as a means to promote the Maillard reaction in the reducing sugars-glutamic acid-Na solutions.

  11. Detachment of Conductive Coatings by Pulsed Electromagnetic Field

    OpenAIRE

    Mironov, V.; Tatarinov, A.; Kolbe, M; Gluschenkov, V.

    2016-01-01

    The paper presents results of studies on the detachment of conductive coatings from the metal substrate by pulsed electromagnetic field (PEMF). It is known that at the boundary of a metal substrate and an electrically conductive coating having different electrical conductivities sharp changes of PEMF strength arise. This effect has been used to remove a copper layer from a steel substrate. Experimental studies were carried out in the Riga Technical University (Latvia), West Sax...

  12. Effects of Combined Pulsed Electric Field and Heat Treatment on Texture Characteristics of Whey Protein Gels%脉冲电场协同加热对乳清蛋白凝胶质构特性的影响

    Institute of Scientific and Technical Information of China (English)

    金声琅; 殷涌光; 王莹

    2013-01-01

    By using whey protein isolate as the target, some treating conditions affecting the hardness, elasticity and water holding capacity of the whey protein gels were investigated by the single-factor experiments, among which the electric field strength, pulse numbers and heating temperature varied from 15 to 55 kV/cm, 2 to 8 and 50 to 90℃ , respectively. The research found that properties of the formed gel have shown significant change after being treated by the high intensity pulsed electric field. Compared with whey protein without effect from the high intensity pulsed electric field, the hardness, elasticity and water holding capacity of gel decreased when the electric field strength varied from 15 to 25 kV/cm, increased significantly when the electric field strength was 35 kV/cm, but decreased again when the electric field strength was 45 kV/cm. When the electric field strength was 35 kV/cm, the hardness, elasticity and water holding capacity of gel strengthened with the increase of pulse number, but the later amplification was not remarkable. When heating temperature was 80℃ , the hardness and elasticity of gel reached their best. The water holding capacity showed optimal performance when heating temperature was 70℃.%以乳清蛋白为研究对象,在电场强度15 ~ 55 kV/cm、脉冲数2~8个、水浴温度50~90℃范围内,通过单因素试验考察各因素对乳清蛋白硬度、弹性和保水性的影响.研究结果表明:乳清蛋白经高压脉冲电场作用后,所形成凝胶的性质有显著变化.与未受高压脉冲电场处理的对照样相比,凝胶硬度、弹性和保水性在电场强度15~25 kV/cm时降低,在电场强度35 kV/cm时显著提高,45 kV/cm时又降低.在电场强度35 kV/cm条件下,凝胶硬度、弹性和保水性随着脉冲数的增加而增强,但后期增幅变化不显著.凝胶硬度和弹性在水浴温度为80℃时最佳,保水性在水浴温度为70℃时最佳.

  13. Biological Effects of Pulsed Electric Field Based on Potential Fluctuations in Maize Seedlings%基于玉米幼苗电位波动的脉冲电场生物学效应

    Institute of Scientific and Technical Information of China (English)

    习岗; 刘锴; 杨运经; 高宇

    2013-01-01

    为了获取显著的电场生物学效应,通过小波降噪和功率谱分析研究了玉米幼苗本征电位波动的基本特征.研究发现,玉米幼苗本征电位波动的功率谱主要分布在1 Hz以内,重心频率为0.2 Hz.采用电场强度为100kV/m、频率为0.2 Hz的极低频脉冲电场处理萌发玉米种子,在萌发第5d时玉米种子的质量、芽长和根长分别比对照组增加17.55%、60.13%和28.50%.分析萌发种子超弱发光的变化时发现,在萌发第5d时,处理组玉米种子的自发发光和延迟发光积分强度分别比对照组增加了68.84%和33.93%,表明0.2 Hz脉冲电场加速了玉米萌发过程中DNA合成反应和细胞代谢.脉冲电场与植物电位的耦合共振可能是极低频脉冲电场具有显著生物学效应的原因.%In order to obtain remarkable electric field biological effect on crop seeds, the basic characteristics of natural potential fluctuations in maize seedlings were studied by analyzing the wavelet de-noising and power spectrum. The results showed that the power spectrum of natural potential fluctuations in maize seedlings was mainly distributed in 0~1 Hz with a gravity frequency of 0. 2 Hz. Based on the potential fluctuation characteristics, extremely low frequency pulsed electric field of 100 kV/m and 0. 2 Hz was used to treat germinating maize seeds. It was found that the seed germination process was significantly promoted: on the 5th day of germination, the fresh mass, shoot length and root length of germinating maize seed respectively increased by 17.55%, 60.13% and 28. 50% compared with those of the control group. Analysis results of ultraweak luminescence(UL) changes in the geminating seeds showed that the ultraweak luminescence was promoted by the pulsed electric field: the spontaneous luminescence and the integrated intensity of delayed luminescence of the germinating maize seed respectively increased by 68. 84% and 33. 93% compared with those of the control

  14. Inverting polar domains via electrical pulsing in metallic germanium telluride

    Science.gov (United States)

    Nukala, Pavan; Ren, Mingliang; Agarwal, Rahul; Berger, Jacob; Liu, Gerui; Johnson, A. T. Charlie; Agarwal, Ritesh

    2017-04-01

    Germanium telluride (GeTe) is both polar and metallic, an unusual combination of properties in any material system. The large concentration of free-carriers in GeTe precludes the coupling of external electric field with internal polarization, rendering it ineffective for conventional ferroelectric applications and polarization switching. Here we investigate alternate ways of coupling the polar domains in GeTe to external electrical stimuli through optical second harmonic generation polarimetry and in situ TEM electrical testing on single-crystalline GeTe nanowires. We show that anti-phase boundaries, created from current pulses (heat shocks), invert the polarization of selective domains resulting in reorganization of certain 71o domain boundaries into 109o boundaries. These boundaries subsequently interact and evolve with the partial dislocations, which migrate from domain to domain with the carrier-wind force (electrical current). This work suggests that current pulses and carrier-wind force could be external stimuli for domain engineering in ferroelectrics with significant current leakage.

  15. Inverting polar domains via electrical pulsing in metallic germanium telluride

    Science.gov (United States)

    Nukala, Pavan; Ren, Mingliang; Agarwal, Rahul; Berger, Jacob; Liu, Gerui; Johnson, A. T. Charlie; Agarwal, Ritesh

    2017-01-01

    Germanium telluride (GeTe) is both polar and metallic, an unusual combination of properties in any material system. The large concentration of free-carriers in GeTe precludes the coupling of external electric field with internal polarization, rendering it ineffective for conventional ferroelectric applications and polarization switching. Here we investigate alternate ways of coupling the polar domains in GeTe to external electrical stimuli through optical second harmonic generation polarimetry and in situ TEM electrical testing on single-crystalline GeTe nanowires. We show that anti-phase boundaries, created from current pulses (heat shocks), invert the polarization of selective domains resulting in reorganization of certain 71o domain boundaries into 109o boundaries. These boundaries subsequently interact and evolve with the partial dislocations, which migrate from domain to domain with the carrier-wind force (electrical current). This work suggests that current pulses and carrier-wind force could be external stimuli for domain engineering in ferroelectrics with significant current leakage. PMID:28401949

  16. Experimental Study of SO2 Removal by Pulsed DBD Along with the Application of Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    RONG Ming-zhe; LIU Ding-xin; WANG Xiao-hua; WANG Jun-hua

    2007-01-01

    Dielectric barrier discharge (DBD) for SO2 removal from indoor air is investigated.In order to improve the removal efficiency,two novel methods are combined in this paper,namely by applying a pulsed driving voltage with nanosecond rising time and applying a magnetic field.For SO2 removal efficiency,different matches of electric field and magnetic field are discussed.And nanosecond rising edge pulsed power supply and microsecond rising edge pulsed power supply are compared.It can be concluded that a pulsed DBD with nanosecond rising edge should be adopted,and electrical field and magnetic field should be applied in an appropriate match.

  17. Influence of a weak field of pulsed DC electricity on the behavior and incidence of injury in adult Steelhead and Pacific Lamprey

    Science.gov (United States)

    Mesa, Matthew G.; Copeland, Elizabeth S.

    2009-01-01

    Predation by pinnipeds, such as California sea lions Zalophus californianus, Pacific harbor seals Phoca vitulina, and Stellar sea lions Eumetopias jubatus on adult Pacific salmon Oncorhynchus spp in the lower Columbia River has become a serious concern for fishery managers trying to conserve and restore runs of threatened and endangered fish. As a result, Smith-Root, Incorporated (SRI; Vancouver, Washington), manufacturers of electrofishing and closely-related equipment, proposed a project to evaluate the potential of an electrical barrier to deter marine mammals and reduce the amount of predation on adult salmonids (SRI 2007). The objectives of their work were to develop, deploy, and evaluate a passive, integrated sonar and electric barrier that would selectively inhibit the upstream movements of marine mammals and reduce predation, but would not injure pinnipeds or impact anadromous fish migrations. However, before such a device could be deployed in the field, concerns by regional fishery managers about the potential effects of such a device on the migratory behavior of Pacific salmon, steelhead O. mykiss, Pacific lampreys Entoshpenus tridentata, and white sturgeon Acipenser transmontanus, needed to be addressed. In this report, we describe the results of laboratory research designed to evaluate the effects of prototype electric barriers on adult steelhead and Pacific lampreys.

  18. Strong and superstrong pulsed magnetic fields generation

    CERN Document Server

    Shneerson, German A; Krivosheev, Sergey I

    2014-01-01

    Strong pulsed magnetic fields are important for several fields in physics and engineering, such as power generation and accelerator facilities. Basic aspects of the generation of strong and superstrong pulsed magnetic fields technique are given, including the physics and hydrodynamics of the conductors interacting with the field as well as an account of the significant progress in generation of strong magnetic fields using the magnetic accumulation technique. Results of computer simulations as well as a survey of available field technology are completing the volume.

  19. Pulsed field gel electrophoresis a practical guide

    CERN Document Server

    Birren, Bruce

    1993-01-01

    Pulsed Field Gel Electrophoresis: A Practical Guide is the first laboratory manual to describe the theory and practice of this technique. Based on the authors' experience developing pulsed field gel instruments and teaching procedures, this book provides everything a researcher or student needs to know in order to understand and carry out pulsed field gel experiments. Clear, well-tested protocols assume only that users have a basic familiarity with molecular biology. Thorough coverage of useful data, theory, and applications ensures that this book is also a lasting resource for more adv

  20. Pulsed electrical discharge in gas bubbles in water

    Science.gov (United States)

    Gershman, Sophia

    A phenomenological picture of pulsed electrical discharge in gas bubbles in water is produced by combining electrical, spectroscopic, and imaging methods. The discharge is generated by applying one microsecond long 5 to 20 kilovolt pulses between the needle and disk electrodes submerged in water. A gas bubble is generated at the tip of the needle electrode. The study includes detailed experimental investigation of the discharge in argon bubbles and a brief look at the discharge in oxygen bubbles. Imaging, electrical characteristics, and time-resolved optical emission data point to a fast streamer propagation mechanism and formation of a plasma channel in the bubble. Spectroscopic methods based on line intensity ratios and Boltzmann plots of line intensities of argon, atomic hydrogen, and argon ions and the examination of molecular emission bands from molecular nitrogen and hydroxyl radicals provide evidence of both fast beam-like electrons and slow thermalized ones with temperatures of 0.6 -- 0.8 electron-volts. The collisional nature of plasma at atmospheric pressure affects the decay rates of optical emission. Spectroscopic study of rotational-vibrational bands of hydroxyl radical and molecular nitrogen gives vibrational and rotational excitation temperatures of the discharge of about 0.9 and 0.1 electron-volt, respectively. Imaging and electrical evidence show that discharge charge is deposited on the bubble wall and water serves as a dielectric barrier for the field strength and time scales of this experiment. Comparing the electrical and imaging information for consecutive pulses applied at a frequency of 1 Hz indicates that each discharge proceeds as an entirely new process with no memory of the previous discharge aside from long-lived chemical species, such as ozone and oxygen. Intermediate values for the discharge gap and pulse duration, low repetition rate, and unidirectional character of the applied voltage pulses make the discharge process here unique

  1. Microfluidic Screening of Electric Fields for Electroporation

    Science.gov (United States)

    Garcia, Paulo A.; Ge, Zhifei; Moran, Jeffrey L.; Buie, Cullen R.

    2016-02-01

    Electroporation is commonly used to deliver molecules such as drugs, proteins, and/or DNA into cells, but the mechanism remains poorly understood. In this work a rapid microfluidic assay was developed to determine the critical electric field threshold required for inducing bacterial electroporation. The microfluidic device was designed to have a bilaterally converging channel to amplify the electric field to magnitudes sufficient to induce electroporation. The bacterial cells are introduced into the channel in the presence of SYTOX®, which fluorescently labels cells with compromised membranes. Upon delivery of an electric pulse, the cells fluoresce due to transmembrane influx of SYTOX® after disruption of the cell membranes. We calculate the critical electric field by capturing the location within the channel of the increase in fluorescence intensity after electroporation. Bacterial strains with industrial and therapeutic relevance such as Escherichia coli BL21 (3.65 ± 0.09 kV/cm), Corynebacterium glutamicum (5.20 ± 0.20 kV/cm), and Mycobacterium smegmatis (5.56 ± 0.08 kV/cm) have been successfully characterized. Determining the critical electric field for electroporation facilitates the development of electroporation protocols that minimize Joule heating and maximize cell viability. This assay will ultimately enable the genetic transformation of bacteria and archaea considered intractable and difficult-to-transfect, while facilitating fundamental genetic studies on numerous diverse microbes.

  2. Electric Field Uniformity of TEPC

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Wei-hua; WANG; Zhi-qiang; LIU; Yi-na; LI; Chun-juan; LUO; Hai-long

    2012-01-01

    <正>As a proportional counter, the problem with tissue-equivalent proportional counter (TEPC) is that near the end of the anode wire the wall of detector is much closer to the anode, the electric field is stronger, and the gas gain is higher than at the center of the anode, namely end effects. In order to optimize the design of TEPC, a gas-flow TEPC (Fig. 1) is designed and constructed to take the research of electric field distribution characteristics.

  3. Dependence of electric field on STM tip preparation

    DEFF Research Database (Denmark)

    Huang, D.H.; Grey, Francois; Aono, M.

    1998-01-01

    Voltage pulses applied between an STM tip and a surface can modify the surface on the nanometer scale due to electric-field-induced evaporation. However, at present, different groups have achieved surface modification with quite different bias conditions, and it is still difficult to obtain high...... reproducibility in such experiments. In this paper, we measure the tip displacement during a pulse at constant tunnelling current, and deduce that the electric field produced by the pulse depends in a systematic way on tip preparation, The results show how differences in tip preparation can be a major source...

  4. Effective Action of Scalar QED in Electric Field Backgrounds

    CERN Document Server

    Kim, Sang Pyo; Yoon, Yongsung

    2008-01-01

    We use the evolution operator method to find the one-loop effective action of scalar QED in electric field backgrounds in terms of the Bogoliubov coefficient between the ingoing and the outgoing vacuum. The effective action shows the general relation between the vacuum persistence and the mean number of created pairs for any electric field. We obtain the exact effective action for a constant electric field and a pulsed electric field, E_0 sech^2 (t/tau), and show that the imaginary part correctly yields the vacuum persistence.

  5. Linear electric field time-of-flight ion mass spectrometer

    Science.gov (United States)

    Funsten, Herbert O.; Feldman, William C.

    2008-06-10

    A linear electric field ion mass spectrometer having an evacuated enclosure with means for generating a linear electric field located in the evacuated enclosure and means for injecting a sample material into the linear electric field. A source of pulsed ionizing radiation injects ionizing radiation into the linear electric field to ionize atoms or molecules of the sample material, and timing means determine the time elapsed between ionization of atoms or molecules and arrival of an ion out of the ionized atoms or molecules at a predetermined position.

  6. Revisiting the Corotation Electric Field

    Science.gov (United States)

    Rothwell, P. L.

    2001-05-01

    The rotation of the Earth's dipole magnetic field produces a corotation electric field in the nonrotating frame of reference. A quick calculation implies that this field might arise from the relative motion of an observer in the nonrotating frame and the motion of rotating magnetic field lines. However, upon applying Faraday's Law one finds that total time rate of change of the magnetic field as seen in the nonrotating frame is zero due to the azimuthal symmetry of the dipole. Therefore, classical EM theory(1) predicts a zero corotation electric field in the nonrotating frame for a vacuum. This conundrum has been traditionally treated in the following manner(2,3). 1) Start with a vacuum state with no conductors and plasma present. The transformation between E (the electric field in the nonrotating frame) and E' (the electric field in the rotating frame)implies that in the rotating frame E' is nonzero while E = 0. 2) In the presence of a thin conducting spherical shell (the ionosphere) polarization charges form in the shell due to the magnetic force on the electrons. A polarization electric field Ep is created such that in the idealized case the shell has a uniform electric potential. This Ep has a component along the magnetic field lines outside the shell. 3) Plasma will polarize along B, thus canceling the parallel component of Ep which allows the potential on the shell to be mapped along the magnetic field lines setting E' = 0. From the transformation equation E is now nonzero. This is the electric field required in the nonrotating frame for the plasma to corotate with the dipole. The presence of the corotation electric field is not a local result, but a nonlocal effect that requires the presence of an ionosphere and a conducting plasma. (1) W.K.H. Panofsky and M. Phillips, Classical Electricity and Magnetism, Addison-Wesley, 1956. (2) H. Alfven and C.-G. Falthammar, Cosmical Electrodynamics, 2nd ed., Oxford Press, 1963. (3) E.W.Hones and J.E.Bergeson, J. Geophys

  7. Wuhan pulsed high magnetic field center

    OpenAIRE

    Li, Liang; Peng, Tao; Ding, Honfa; Han, Xiaotao; Ding, Tonghai; Chen, Jin; Wang, Junfeng; Xie, Jianfeng; Wang, Shaoliang; Duan, Xianzhong; Wang, Cheng; Herlach, Fritz; Vanacken, Johan; Pan, Yuan

    2008-01-01

    Wuhan pulsed high magnetic field facility is under development. Magnets of bore sizes from 12 to 34 mm with the peak field in the range of 50 to 80 T have been designed. The pulsed power supplies consists of a 12 MJ, 25 kV capacitor bank and a 100 MVA/100 MJ flywheel pulse generator. A prototype 1 MJ, 25 kV capacitor bank is under construction. Five magnets wound with CuNb wire and copper wire reinforced internally with Zylon fiber composites and externally with stainless steel shells have be...

  8. Wuhan pulsed high magnetic field center

    OpenAIRE

    Li, Liang; Peng, Tao; Ding, Honfa; Han, Xiaotao; Ding, Tonghai; Chen, Jin; Wang, Junfeng; Xie, Jianfeng; Wang, Shaoliang; DUAN, Xianzhong; Wang, Cheng; Herlach, Fritz; Vanacken, Johan; Pan, Yuan

    2008-01-01

    Wuhan pulsed high magnetic field facility is under development. Magnets of bore sizes from 12 to 34 mm with the peak field in the range of 50 to 80 T have been designed. The pulsed power supplies consists of a 12 MJ, 25 kV capacitor bank and a 100 MVA/100 MJ flywheel pulse generator. A prototype 1 MJ, 25 kV capacitor bank is under construction. Five magnets wound with CuNb wire and copper wire reinforced internally with Zylon fiber composites and externally with stainless steel shells have be...

  9. Assessment of pulsed DC electric field to guide downstream migrating sea lamprey in experimental flume at USGS Conte Anadromous Fish Lab, Turners Falls, MA (December 2013)

    Science.gov (United States)

    Miehls, Scott M.; Johnson, Nicholas; Haro, Alexander J.

    2017-01-01

    This is a tabular data set that contains records of water velocity, depth, temperature and trial information such as start and stop times and date for experimental trials testing the effect of an electric field on the movement patterns and distribution of juvenile sea lamprey moving downstream in an experimental flume. Distribution is recorded for each individual lamprey as presence (1) or absence (0) in a series of downstream collection nets positions laterally across the flume. The data is formatted as comma delimited and contains no special characters. The trails were conducted during December 2 through December 15, 2013 in a 6 meter wide experimental flume at the Conte Anadromous Fish Research Lab in Turners Falls, MA.

  10. High-frequency and brief-pulse stimulation pulses terminate cortical electrical stimulation-induced afterdischarges.

    Science.gov (United States)

    Ren, Zhi-Wei; Li, Yong-Jie; Yu, Tao; Ni, Duan-Yu; Zhang, Guo-Jun; Du, Wei; Piao, Yuan-Yuan; Zhou, Xiao-Xia

    2017-06-01

    Brief-pulse stimulation at 50 Hz has been shown to terminate afterdischarges observed in epilepsy patients. However, the optimal pulse stimulation parameters for terminating cortical electrical stimulation-induced afterdischarges remain unclear. In the present study, we examined the effects of different brief-pulse stimulation frequencies (5, 50 and 100 Hz) on cortical electrical stimulation-induced afterdischarges in 10 patients with refractory epilepsy. Results demonstrated that brief-pulse stimulation could terminate cortical electrical stimulation-induced afterdischarges in refractory epilepsy patients. In conclusion, (1) a brief-pulse stimulation was more effective when the afterdischarge did not extend to the surrounding brain area. (2) A higher brief-pulse stimulation frequency (especially 100 Hz) was more likely to terminate an afterdischarge. (3) A low current intensity of brief-pulse stimulation was more likely to terminate an afterdischarge.

  11. Effect of Pulsed Electric Field on Particle Distribution Properties of Powder Phosphatides Dispersion System%脉冲电场对粉末磷脂分散体系颗粒性质的影响

    Institute of Scientific and Technical Information of China (English)

    贾晓; 曾新安

    2012-01-01

    The effect of pulsed electric field (PEF) treatment on particle properties of powder phosphatides dispersion system was studied. The results showed that the size distribution of powder phosphatides was significantly narrowed and shifted towards smaller size direction with the increase of electric field strength and number of applied pulses, The average particle size was reduced by 65.8% from 594.4 nm (contrast) to 203 nm at a filed intensity of 70 kV/cm. It was demonstrated that the particle size was decreased to 511.2 nm under lower filed intensity (20 kV/cm) with 50 pulses, and to 349.7 nm under higher filed intensity (60 kV/cm) with 25 pulses, Therefore, small particles can be easily obtained after PEF treatment with higher filed intensity and less pulse number,%研究高强脉冲电场(PEF)对磷脂水溶液分散体系颗粒性质的影响。结果表明:增大脉冲电场场强和脉冲数的输入,体系粒径分布区间明显变窄且向较小方向移动;在场强为70kV/cm条件下,卜均粒径(dM)山未施加电脉处理下的594.4nm减为203nm,相比未施加电场样品减少了65.8%;低场强(20kV/cm)处理下,50个脉冲处理下dM为511.2nm,而在高场强(60kV/cm)条件下,25个脉冲处理时,幽为349.7nm,说明在高场强处理下,能够在较少的脉冲数输入下,获得较小的颗粒粒径。

  12. THOR Electric Field Instrument - EFI

    Science.gov (United States)

    Khotyaintsev, Yuri; Bale, Stuart D.; Rothkaehl, Hanna; Bonnell, John; Åhlen, Lennart; Vaivads, Andris; Lindqvist, Per-Arne; Ivchenko, Nickolay; Soucek, Jan

    2017-04-01

    Turbulence Heating ObserveR (THOR) is the first mission ever flown in space dedicated to plasma turbulence. The Electric Field Instrument (EFI) is to measure the electric field vector in the frequency range 0-200 kHz. EFI consists of two sets of sensors: Spin-plane Double Probes (EFI-SDP) providing high sensitivity DC electric field in the spacecraft spin plane (2D), and the High-Frequency Antenna (EFI-HFA) providing 3D electric field at frequencies above 1 kHz. EFI-SDP consists of 4 biased spherical probes extended on 50 m long wire booms, 90 degrees apart in the spin plane, giving a 100 m baseline for each of the two spin-plane electric field components. EFI-HFA consists of 6 x 1.25 m long monopoles, forming 3 dipolar antennas crossed at 90 degrees to each other. In addition to the sensors, EFI contains HFA and SDP pre-amplifiers, as well as bias electronics boards (BEBs) hosted in the man electronics box of the Field and Wave processor (FWP). As THOR spacecraft has a sun-pointing spin axis, EFI-SDP measures the electric field in the plane approximately orthogonal to the sun using long wire booms. The sun-pointing attitude greatly reduces errors due to wake effects and asymmetric photoelectron clouds, enabling the highly accurate in comparison to earlier missions ±0.1 mV/m near-DC electric field measurements. Interferometry using the electric field probes can be used to infer wavelengths and scale sizes at the smallest scales in the plasma. EFI also measures the floating potential of the satellite, which can be used to estimate the plasma density at very high time resolution (up to a few hundred Hz). The sun-pointing attitude greatly reduces changes in the illuminated area, and hence the associated spin-dependent errors. In combination with densities derived from the observed plasma frequency emission line, EFI monitors the plasma density from DC to a few hundred Hz. EFI measurements characterize electric field and density variations associated with kinetic

  13. Electric fields and quantum wormholes

    CERN Document Server

    Engelhardt, Dalit; Iqbal, Nabil

    2015-01-01

    Electric fields can thread a classical Einstein-Rosen bridge. Maldacena and Susskind have recently suggested that in a theory of dynamical gravity the entanglement of ordinary perturbative quanta should be viewed as creating a quantum version of an Einstein-Rosen bridge between the particles, or a "quantum wormhole". We demonstrate within low-energy effective field theory that there is a precise sense in which electric fields can also thread such quantum wormholes. We define a non-perturbative "wormhole susceptibility" that measures the ease of passing an electric field through any sort of wormhole. The susceptibility of a quantum wormhole is suppressed by powers of the U(1) gauge coupling relative to that for a classical wormhole but can be made numerically equal with a sufficiently large amount of entangled matter.

  14. Electric fields and quantum wormholes

    Science.gov (United States)

    Engelhardt, Dalit; Freivogel, Ben; Iqbal, Nabil

    2015-09-01

    Electric fields can thread a classical Einstein-Rosen bridge. Maldacena and Susskind have recently suggested that in a theory of dynamical gravity the entanglement of ordinary perturbative quanta should be viewed as creating a quantum version of an Einstein-Rosen bridge between the particles, or a "quantum wormhole." We demonstrate within low-energy effective field theory that there is a precise sense in which electric fields can also thread such quantum wormholes. We define a nonperturbative "wormhole susceptibility" that measures the ease of passing an electric field through any sort of wormhole. The susceptibility of a quantum wormhole is suppressed by powers of the U (1 ) gauge coupling relative to that for a classical wormhole but can be made numerically equal with a sufficiently large amount of entangled matter.

  15. Pulse electric fields effect on invasion and metastasis of Hela cells in human cervical cancer%脉冲电场对人宫颈癌Hela细胞侵袭转移能力的影响

    Institute of Scientific and Technical Information of China (English)

    张琴; 熊正爱; 周玮; 李成祥; 姚陈果

    2011-01-01

    背景:脉冲电场对肿瘤细胞侵袭转移能力是否具有抑制作用尚不十分清楚.目的:探讨不同强度脉冲电场对人宫颈癌Hela细胞侵袭转移能力的影响及可能的机制.方法:以场强分别为0,500,1 000和1 500 V/cm的脉冲电场作用人宫颈癌Hela细胞后,采用平板克隆形成实验,观察脉冲电场对细胞克隆能力的影响;采用Transwell小室进行人工重组基底膜侵袭和转移实验,观察脉冲电场对细胞侵袭和转移能力的影响;采用RT-PCR法检测宫颈癌Hela细胞中基质金属蛋白酶2和RhoC基因mRNA的表达情况.结果与结论:脉冲电场作用后,宫颈癌Hela细胞的克隆能力受到抑制;细胞侵袭和转移能力明显降低;基质金属蛋白酶2和RhoC基因mRNA的表达均明显减弱,且有电场强度依赖性.结果表明,脉冲电场能抑制人宫颈癌Hela细胞的侵袭转移能力,其机制可能与降低RhoC和基质金属蛋白酶2的表达有关.%BACKGROUND: The inhibitory effect of pulse electric fields on invesion and metastasi s ability of tumor cells is unclear.OBJECTIVE: To explore the impact of different intensity pulse electric fields on the human cervical carcinoma Hela cell invasion and metastasis and its possible mechanism.METHODS: The electric fields with intensity of 0, 500, 1 000 and 1 500 V/cm were performed on the human cervical carcinoma Hela cell. The clone capacity was measured with flat clone formation experiment; the invasion and immigration capacity was evaluated with transwell cave method;the expression level of mRNA of MMP-2 and RhoC was detected by RT-PCR method.RESULTS AND CONCLUSION: After being treated with pulsed electric fields, the clone capacity of Hela cells was inhibited. The invasion and immigration capacity of Hela cells were also inhibited. The expression level of mRNA of matrix metalloproteinase 2 (MMP-2) and RhoC were decreased. The pulse electric fields could affect the invasion and metastasis capacity of the human

  16. Synaptic Effects of Electric Fields

    Science.gov (United States)

    Rahman, Asif

    Learning and sensory processing in the brain relies on the effective transmission of information across synapses. The strength and efficacy of synaptic transmission is modifiable through training and can be modulated with noninvasive electrical brain stimulation. Transcranial electrical stimulation (TES), specifically, induces weak intensity and spatially diffuse electric fields in the brain. Despite being weak, electric fields modulate spiking probability and the efficacy of synaptic transmission. These effects critically depend on the direction of the electric field relative to the orientation of the neuron and on the level of endogenous synaptic activity. TES has been used to modulate a wide range of neuropsychiatric indications, for various rehabilitation applications, and cognitive performance in diverse tasks. How can a weak and diffuse electric field, which simultaneously polarizes neurons across the brain, have precise changes in brain function? Designing therapies to maximize desired outcomes and minimize undesired effects presents a challenging problem. A series of experiments and computational models are used to define the anatomical and functional factors leading to specificity of TES. Anatomical specificity derives from guiding current to targeted brain structures and taking advantage of the direction-sensitivity of neurons with respect to the electric field. Functional specificity originates from preferential modulation of neuronal networks that are already active. Diffuse electric fields may recruit connected brain networks involved in a training task and promote plasticity along active synaptic pathways. In vitro, electric fields boost endogenous synaptic plasticity and raise the ceiling for synaptic learning with repeated stimulation sessions. Synapses undergoing strong plasticity are preferentially modulated over weak synapses. Therefore, active circuits that are involved in a task could be more susceptible to stimulation than inactive circuits

  17. Improvement of antioxidant peptides activity of Korean pine seed by pulsed electric field technology%高压脉冲电场技术提高红松籽抗氧化肽活性

    Institute of Scientific and Technical Information of China (English)

    张鸣镝; 姜源; 李雄; 李雪楠; 林松毅

    2015-01-01

    The effects of pulsed electric field (PEF) on auxiliarily improving activity of antioxidant peptides were investigated. In this study, the Korean pine seed antioxidant peptides with molecular weight ranging from 1 to 3 kDa were used as raw materials and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical inhibition was used as testing index. In order to develop and optimize the parameters of DPPH radical inhibition, we have investigated 3 variables, including electric field intensity (kV/cm), pulse frequency (Hz) and flow velocity (mL/min). By means of one-factor-at-a-time (OFAT) and response surface metrology (RSM) experiment, the technological parameters of the PEF treatment were optimized. The OFAT research showed that the DPPH radical inhibition reached the highest value 89.08%±1.08% when the residence time of the treated sample by PEF was 4 h, the DPPH radical inhibition reached the highest value 90.53%±0.85% when the electric field intensity was 12.5 kV/cm, and the DPPH radical inhibition reached the highest value 89.08 % ± 0.54 % when the ratio of electric frequency was 2000 Hz. Based on the RSM research, the results showed that, the electric field intensity of PEF was 11.5 kV/cm, the pulse frequency was 1494 Hz, the flow velocity was 4.8 mL/min, the predictive value of the DPPH radical inhibition was 83.58%. Taking into account the specific conditions of the device, the process parameters were corrected for the electric field intensity of PEF treatment to be 11.5 kV/cm, the pulse frequency to be 1500 Hz and the flow velocity to be 4.8 mL/min. And under this condition, the DPPH radical inhibition was 86.93%±0.31%. While the DPPH radical inhibition was 68.16%±0.25% when the sample Korean pine seed antioxidant peptides did not be treated by PEF. The removal rate of DPPH was increased by 18.77% compared with the untreated by PEF. The Mid-infrared spectroscopy (MIR) was used to analyze the structure of Korean pine seed antioxidant peptides under the optimal PEF

  18. Effect of Pulsed Electric Fields on Sterilization and Quality of Blueberry Juice%高压脉冲电场对蓝莓汁杀菌效果及品质的影响

    Institute of Scientific and Technical Information of China (English)

    陶晓赟; 王寅; 陈健; 李路宁; 孙爱东

    2012-01-01

    The study evaluated the sterilizing effect of pulsed electric fields (PEF) on Escherichia coli in blueberry juice and its impact on physicochemical property of blueberry juice. The results showed that the inactivation effect of Escherichia coli was enhanced when the electric field strength and total treatment time were increased. With PEF treatments at 35 kV/cm and 82 ~s, the reduction of Escherichia coli was 5. 12 logarithms. When the electric field strength was constant and the electric conductivity was increased, the inactivation effect of Escherichia coli declined slightly. PEF had no significant effect on the content of vitamin C, anthocyanin, total phenols, titratable acids, re- ducing sugar, and Brix in blueberry juice and its color.%研究了高压脉冲电场(PEF)对蓝莓汁的杀菌效果及其对蓝莓汁理化性质的影响。结果显示:随电场强度、处理时间的增大,PEF对蓝莓汁中大肠杆菌的杀灭效果增强。当电场强度为35kV/cm,处理时间为82μs时,蓝莓汁中大肠杆菌致死率为5.12个对数。电场强度一定时,电导率增大,PEF对大肠杆菌的钝化效果略微下降。PEF对蓝莓汁Vc、花青素、总酚、可滴定酸、还原糖、可溶性固形物及色泽等理化性质没有影响。

  19. Trapped magnetic field measurements on HTS bulk by peak controlled pulsed field magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Ida, Tetsuya; Watasaki, Masahiro [Department of Electronic Control Engineering, Hiroshima National College of Maritime Technology, 4272-1, Higashino, Ohsakikamijima-cho, Toyota-gun, Hiroshima 725-0231 (Japan); Kimura, Yosuke [Kawasaki Heavy Industries, Ltd. Technical Institute System Technology Development Centre 1-1, Kawasaki-cho, Akashi-shi, Hyogo 673-8666 (Japan); Miki, Motohiro; Izumi, Mitsuru, E-mail: ida@hiroshima-cmt.ac.j [Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan)

    2010-06-01

    For the past several years, we have studied the high-temperature superconducting (HTS) synchronous motor assembled with melt-textured Gd-Ba-Cu-O bulk magnets. If the single pulse field magnetizes a bulk effectively, size of electrical motor will become small for the strong magnetic field of the HTS magnets without reducing output power of motor. In the previous study, we showed that the HTS bulk was magnetized to excellent cone-shape magnetic field distribution by using the waveform control pulse magnetization (WCPM) method. The WCPM technique made possible the active control of the waveform on which magnetic flux motion depended. We generated the pulse waveform with controlled risetime for HTS bulk magnetization to suppress the magnetic flux motion which decreases magnetization efficiency. The pulsed maximum magnetic flux density with slow risetime is not beyond the maximum magnetic flux density which is trapped by the static field magnetization. But, as for applying the pulse which has fast risetime, the magnetic flux which exceed greatly the threshold penetrates the bulk and causes the disorder of the trapped magnetic distribution. This fact suggests the possibility that the threshold at pulsed magnetization influences the dynamic magnetic flux motion. In this study, Gd-Ba-Cu-O bulk is magnetized by the controlled arbitrary trapezoidal shape pulse, of which the maximum magnetic flux density is controlled not to exceed the threshold. We will present the trapped magnetic characteristics and the technique to generate the controlled pulsed field.

  20. Field mapping of ballistic pressure pulse sources

    Directory of Open Access Journals (Sweden)

    Rad Abtin Jamshidi

    2015-09-01

    Full Text Available Ballistic pressure pulse sources are used since late 1990s for the extracorporeal treatment of chronic Enthesitis. Newly indications are found in trigger-point-therapy for the treatment of musculoskeletal disorders. In both applications excellent results without relevant side effects were found in clinical trials. The technical principle of pressure pulse source is based on the same techniques used in air guns. A projectile is accelerated by pressurized air and hits the applicator with high kinetic energy. By this a compression wave travels through the material and induces a fast (4..5μs, almost singular pressure pulse of 2..10 MPa, which is followed by an equally short rarefaction phase of about the same amplitude. It is assumed that the pressure pulse accounts for the biomedical effects of the device. The slower inertial motion of the waveguide is damped by elastic stoppers, but still can be measured several micro seconds after the initial pressure pulse. In order to characterize the pressure pulse devices, field mapping is performed on several radial pressure pulse sources using the fiber optic hydrophone and a polyvinylidenfluorid (PVDF piezoelectric hydrophone. It could be shown that the current standard (IEC 61846 is not appropriate for characterization of ballistic pressure pulse sources.

  1. Magnetic Linear Birefringence Measurements Using Pulsed Fields

    CERN Document Server

    Berceau, Paul; Battesti, Remy; Rizzo, Carlo

    2011-01-01

    In this paper we present the accomplishment of the further step towards the vacuum magnetic birefringence measurement based on pulsed fields. After describing our BMV experiment, we report the calibration of our apparatus with nitrogen gas and we discuss the precision of our measurement giving a detailed error budget. Our best present vacuum sensitivity is 2.1x 10^-19 T^-2 per 5 ms magnetic pulse. We finally discuss the perspectives to reach our final goal.

  2. Permeabilization of yeast Saccharomyces cerevisiae cell walls using nanosecond high power electrical pulses

    Science.gov (United States)

    Stirke, A.; Zimkus, A.; Balevicius, S.; Stankevic, V.; Ramanaviciene, A.; Ramanavicius, A.; Zurauskiene, N.

    2014-12-01

    The electrical field-induced changes of the yeast Saccharomyces cerevisiae cells permeabilization to tetraphenylphosphonium (TPP+) ions were studied using square-shaped, nanosecond duration high power electrical pulses. It was obtained that pulses having durations ranging from 10 ns to 60 ns, and generating electric field strengths up to 190 kV/cm significantly (up to 65 times) increase the absorption rate of TPP+ ions without any detectible influence on the yeast cell viability. The modelling of the TPP+ absorption process using a second order rate equation demonstrates that depending on the duration of the pulses, yeast cell clusters of different sizes are homogeniously permeabilized. It was concluded, that nanosecond pulse-induced permeabilization can be applied to increase the operational speed of whole cell biosensors.

  3. 高压脉冲电场技术在食品加工中的应用研究新进展%Review on Novel Application of Pulsed Electric Fields in Food Processing

    Institute of Scientific and Technical Information of China (English)

    刘凤霞; 孙建霞; 李静; 廖小军

    2010-01-01

    作为一项重要的非热加工技术,高压脉冲电场(pulsed electric field,简称PEF)已成为目前食品杀菌与钝酶工艺研究中最为活跃的技术之一.随着PEF应用研究的不断深入和拓宽,PEF在物质定向改性、目标成分提取、食品干燥、食品冷冻与解冻、果蔬榨汁、酒类陈酿以及农药降解等方面的应用也越来越多,文中总结归纳了近年来PEF在这些方面的研究进展,以期为PEF技术的深入研究与广泛应用提供参考.

  4. Model of Pulsed Electrical Discharge Machining (EDM using RL Circuit

    Directory of Open Access Journals (Sweden)

    Ade Erawan Bin Minhat

    2014-10-01

    Full Text Available This article presents a model of pulsed Electrical Discharge Machining (EDM using RL circuit. There are several mathematical models have been successfully developed based on the initial, ignition and discharge phase of current and voltage gap. According to these models, the circuit schematic of transistor pulse power generator has been designed using electrical model in Matlab Simulink software to identify the profile of voltage and current during machining process. Then, the simulation results are compared with the experimental results.

  5. Research on Sulfur Migration with Pulsed Electric Field Imposed on Slag-metal Interface%渣金间外加脉冲电场对硫元素迁移研究

    Institute of Scientific and Technical Information of China (English)

    王海川; 陈克全; 葛允宗; 廖直友; 陈鹏飞

    2013-01-01

    在Fe-C-S系合金与CaO-MgO-Al2O3溶渣体系间施加电压为2V的脉冲电场,研究了改变脉冲电场的处理时间对S在渣金两相间分布和迁移特性的影响.试验结果表明,随着脉冲处理时间加长,渣中的硫含量逐渐升高,S在Fe-C-S金属基体上下表面分布趋于均匀,当电场处理时间为60 s时,渣中的硫含量为0.891%,△Ws=0.001%,并且金属表面夹杂物明显细化.%Pulsed electric field has been imposed on interface between Fe-C-S alloy and CaO-MgO-Al2O3 slag for different durations to study sulfur distribution and migration between metal and slag. The experimental result shows that with the extension of imposing time, sulfur in the slag gradually increases, and evenly distributes on the upper and lower surfaces of Fe-C-S metallic matrix; in addition, inclusions on the metal surface are obviously refined at the same time. The sulfur content in the slag is 0. 891 percent and △Ws is 0.001 percent when pulsed electric field imposing time is 60 seconds.

  6. Studies on Freeze Concentrated Loquat Juice Treated by Pulsed Electric Field%高压脉冲电场处理冷冻浓缩枇杷汁的研究

    Institute of Scientific and Technical Information of China (English)

    方婷; 钟海荣; 陈锦权

    2011-01-01

    The conductivity of liquid foods will directly influence the strength of Pulsed Electric Field (PEF). The conductivity of liquid foods treated by freeze concentration will decrease which will benefit for sterilization effect of PEF. In this article, freeze concentrated Loquat juice was treated by PEF and the effects of different conditions on liquid foods conductivity were investigated. The results showed that in pretreatments homogeneity and degassing could improve the stabilization and reliability of PEF instrument. After pre - cooling, the conductivity of different concentration Loquat juice was decreasing with the temperature fell down. The sterilization effect of PEF on freeze concentrated Loquat juice was nearly equal to original Loquat juice was only treated by PEF.%液体食品电导率的高低直接影响高压脉冲电场(Pulsed Electric Field,PEF)的电场强度,冷冻浓缩后的液体食品电导率降低,有利于高压脉冲电场的杀菌效果。本研究将冷冻浓缩后的枇杷汁通过高压脉冲电场处理,并探讨不同条件对冷冻浓缩枇杷汁电导率的影响,结果表明:在前处理时,均质、脱气可有效地提高高压脉冲杀菌过程中仪器的稳定性和可靠性;经预冷后的不同浓度枇杷汁的电导率随着温度的降低而逐渐减小,PEF处理冷冻浓缩后枇杷汁的杀菌效果与仅用PEF处理效果相当。

  7. Effect of Oil Viscidity on Optimal Demulsion Frequency in Pulse Electric Field%油液黏度对脉冲电场最佳破乳频率的影响

    Institute of Scientific and Technical Information of China (English)

    龚海峰; 彭烨

    2013-01-01

    通过建立油中乳胶粒子在脉冲电场作用下的非线性振动动力学模型,研究了粒子非线性参激共振及其条件,得出脉冲电场最佳破乳频率关系式.结果表明,油中乳胶粒子最佳破乳频率及其共振振幅随油液黏度的增大而减小.利用模型得出的乳胶粒子振动幅频特性关系在理论上解释了油液黏度对最佳破乳频率产生的影响,以及最佳破乳频率偏离粒子振动固有频率的成因.%By establishing the vibration kinetics model of latex particle in oil under pulse electric field, the characteristics and conditions of latex particle's parametrically excited nonlinear vibration were studied. And then, the optimal demulsion frequency of latex particle was obtained under pulse electric field. In experiment, results showed that the value of optimal demulsion frequency and swing of resonance particle decreased with the increase of oil viscosity. In theory, swing-frequency characteristic relationship of vibrating particle obtained by model explained that oil viscosity could have effect on the optimal demulsion frequency and the reason that optimal demulsion frequency deviated from natural frequency of particle vibration.

  8. 高压脉冲电场激励油中液滴振动计算与实验%Calculation and tests for drop vibration in emulsion oil under high pulse electric field

    Institute of Scientific and Technical Information of China (English)

    龚海峰; 杨智君; 彭烨

    2014-01-01

    以单液滴为研究对象,建立液滴动力学模型,通过求解模型获得液滴振幅一次近似解及幅频特性关系。算例及实验结果表明,液滴非线性振动计算方法合理,液滴动力学模型能对高压脉冲电场激励油中液滴振动进行有效计算,且能预测液滴“共振”频率及振幅。该研究对研制高效电场脱水装置具有指导意义。%Under excitation of high pulse electric field,a drophappens to be in vibration during electro-dehydration of emulsified oil.So far,there are few references about theoretical calculation of drop vibration.A single vibrating drop in oil was regarded as a study object under high pulse electric field,and its dynamic model was built.By solving the model, drop vibration amplitude first approximate solution and its amplitude-frequency characteristic relation were obtained. Results of example calc and tests showed that the non-linear method of vibration calculation is reasonable and it can be used to predict drop's resonance frequency and amplitude.The study results were helpful to making highly efficient electro-dehydration machines.

  9. Microstickies agglomeration by electric field.

    Science.gov (United States)

    Du, Xiaotang Tony; Hsieh, Jeffery S

    2016-01-01

    Microstickies deposits on both paper machine and paper products when it agglomerates under step change in ionic strength, pH, temperature and chemical additives. These stickies increase the down time of the paper mill and decrease the quality of paper. The key property of microstickies is its smaller size, which leads to low removal efficiency and difficulties in measurement. Thus the increase of microstickies size help improve both removal efficiency and reduce measurement difficulty. In this paper, a new agglomeration technology based on electric field was investigated. The electric treatment could also increase the size of stickies particles by around 100 times. The synergetic effect between electric field treatment and detacky chemicals/dispersants, including polyvinyl alcohol, poly(diallylmethylammonium chloride) and lignosulfonate, was also studied.

  10. Apparatuses and methods for generating electric fields

    Science.gov (United States)

    Scott, Jill R; McJunkin, Timothy R; Tremblay, Paul L

    2013-08-06

    Apparatuses and methods relating to generating an electric field are disclosed. An electric field generator may include a semiconductive material configured in a physical shape substantially different from a shape of an electric field to be generated thereby. The electric field is generated when a voltage drop exists across the semiconductive material. A method for generating an electric field may include applying a voltage to a shaped semiconductive material to generate a complex, substantially nonlinear electric field. The shape of the complex, substantially nonlinear electric field may be configured for directing charged particles to a desired location. Other apparatuses and methods are disclosed.

  11. Special Effect of Parallel Inductive Electric Field

    Institute of Scientific and Technical Information of China (English)

    陈涛; 刘振兴; W.Heikkila

    2002-01-01

    Acceleration of electrons by a field-aligned electric field during a magnetospheric substorm in the deep geomagnetic tail is studied by means of a one-dimensional electromagnetic particle code. It was found that the free acceleration of the electrons by the parallel electric field is obvious; kinetic energy variation is greater than electromagnetic energy variation in the presence of parallel electric field. Magnetic energy is greater than kinetic energy variation and electric energy variation in the absence of the parallel electric field. More wave modes in the presence of the parallel electric field are generated than those in the absence of the parallel electric field.

  12. Study of esterification mechanism between acetic acid and ethanol under pulsed electric field%脉冲电场下乙酸乙醇酯化反应机理研究

    Institute of Scientific and Technical Information of China (English)

    林志荣; 曾新安; 于淑娟

    2012-01-01

    The effect of pulsed electric field treatment on esterification between acetic acid and ethanol was investigated in this paper, and esterification mechanism under PEF condition also was discussed through the infrared spectrum method. Results indicated that the reaction was enhanced with increasing electric field strength. Comparing infrared spectrogram with PEF and without PEF, it found 0 - H or C = 0 stretching vibrational absorption center was moving to the higher frequency region. It illustrates PEF destroyed hydrogen bonding connection and C = 0 was polarized further.%主要研究不同场强下脉冲电场(PEF)对乙酸和乙醇酯化反应的影响,并通过红外光谱法探讨电场作用下酯化反应的机理.结果表明:常温无催化剂条件下PEF对乙酸和乙醇的酯化反应有一定的促进作用,且随着场强的增强而增加.比较PEF处理前后样品的红外光谱图,发现O-H、C=O伸缩振动峰均向高频移动,体系内的氢键缔合被破坏,电场下碳氧极性键被进一步极化.

  13. Linear electric field mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    McComas, D.J.; Nordholt, J.E.

    1991-03-29

    A mass spectrometer is described having a low weight and low power requirement, for use in space. It can be used to analyze the ionized particles in the region of the spacecraft on which it is mounted. High mass resolution measurements are made by timing ions moving through a gridless cylindrically sysmetric linear electric field.

  14. Electric fields and quantum wormholes

    NARCIS (Netherlands)

    Engelhardt, D.; Freivogel, B.; Iqbal, N.

    2015-01-01

    Electric fields can thread a classical Einstein-Rosen bridge. Maldacena and Susskind have recently suggested that in a theory of dynamical gravity the entanglement of ordinary perturbative quanta should be viewed as creating a quantum version of an Einstein-Rosen bridge between the particles, or a

  15. Electric fields and quantum wormholes

    NARCIS (Netherlands)

    Engelhardt, D.; Freivogel, B.; Iqbal, N.

    2015-01-01

    Electric fields can thread a classical Einstein-Rosen bridge. Maldacena and Susskind have recently suggested that in a theory of dynamical gravity the entanglement of ordinary perturbative quanta should be viewed as creating a quantum version of an Einstein-Rosen bridge between the particles, or a "

  16. Resistance switching induced by electric fields in manganite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Villafuerte, M [Facultad de Ciencias Exactas y TecnologIa, Universidad Nacional de Tucuman, S. M. de Tucuman (Argentina); Juarez, G [Facultad de Ciencias Exactas y TecnologIa, Universidad Nacional de Tucuman, S. M. de Tucuman (Argentina); Duhalde, S [Dpto de Fisica, Facultad de IngenierIa, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Golmar, F [Dpto de Fisica, Facultad de IngenierIa, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Degreef, C L [Dpto de Fisica, Facultad de IngenierIa, Universidad de Buenos Aires, Paseo Colon 850, 1063 Buenos Aires (Argentina); Heluani, S P [Facultad de Ciencias Exactas y TecnologIa, Universidad Nacional de Tucuman, S. M. de Tucuman (Argentina)

    2007-04-15

    In this work, we investigate the polarity-dependent Electric Pulses Induced Resistive (EPIR) switching phenomenon in thin films driven by electric pulses. Thin films of {sub 0.5}Ca{sub 0.5}MnO{sub 3} (manganite) were deposited by PLD on Si substrate. The transport properties at the interface between the film and metallic electrode are characterized in order to study the resistance switching. Sample thermal treatment and electrical field history are important to be considered for get reproducible EPIR effect. Carriers trapping at the interfaces are considered as a possible explanation of our results.

  17. Numerical simulation of high voltage electric pulse comminution of phosphate ore

    Institute of Scientific and Technical Information of China (English)

    Razavian Seyed Mohammad; Rezai Bahram; Irannajad Mehdi; Ravanji Mohammad Hasan

    2015-01-01

    Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phos-phate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals, the feed particle size and the location of conductive minerals in ores. The angle of material contact sur-face with the discharge electrode is also an important factor in the intensity of electrical field. Moreover, it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with shar-pening the contact angle. Besides, the electrical discharge in the samples is converted to the elec-trohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.

  18. Numerical simulation of electromagnetic and flow fields of TiAI melt under electric field

    Institute of Scientific and Technical Information of China (English)

    Zhang Yong; Ding Hongsheng; Jiang Sanyong; Chen Ruirun; Guo Jingjie

    2010-01-01

    This article aims at building an electromagnetic and fluid model, based on the Maxwell equations and Navier-Stokes equations, in TiAI melt under two electric fields. FEM (Finite Element Method) and APDL (ANSYS Parametric Design Language) were employed to perform the simulation, model setup, loading and problem solving. The melt in molds of same cross section area with different flakiness ratio (i.e. width/depth) under the load of sinusoidal current or pulse current was analyzed to obtain the distribution of electromagnetic field and flow field. The results show that the induced magnetic field occupies sufficiently the domain of the melt in the mold with a flakiness ratio of 5:1. The melt is driven bipolarly from the center in each electric field. It is also found that the pulse electric field actuates the TiAI melt to flow stronger than what the sinusoidal electric field does.

  19. Development of Long-Lifetime Pulsed Gas Valves for Pulsed Electric Thrusters

    Science.gov (United States)

    Burkhardt, Wendel M.; Crapuchettes, John M.; Addona, Brad M.; Polzin, Kurt A.

    2015-01-01

    It is advantageous for gas-fed pulsed electric thrusters to employ pulsed valves so propellant is only flowing to the device during operation. The propellant utilization of the thruster will be maximized when all the gas injected into the thruster is acted upon by the fields produced by the electrical pulse. Gas that is injected too early will diffuse away from the thruster before the electrical pulse can act to accelerate the propellant. Gas that is injected too late will miss being accelerated by the already-completed electrical pulse. As a consequence, the valve must open quickly and close equally quickly, only remaining open for a short duration. In addition, the valve must have only a small amount of volume between the sealing body and the thruster so the front and back ends of the pulse are as coincident as possible with the valve cycling, with very little latent propellant remaining in the feed lines after the valve is closed. For a real mission of interest, a pulsed thruster can be expected to pulse at least 10(exp 10) - 10(exp 11) times, setting the range for the number of times a valve must open and close. The valves described in this paper have been fabricated and tested for operation in an inductive pulsed plasma thruster (IPPT) for in-space propulsion. In general, an IPPT is an electrodeless space propulsion device where a capacitor is charged to an initial voltage and then discharged, producing a high-current pulse through a coil. The field produced by this pulse ionizes propellant, inductively driving current in a plasma located near the face of the coil. Once the plasma is formed, it can be accelerated and expelled at a high exhaust velocity by the electromagnetic Lorentz body force arising from the interaction of the induced plasma current and the magnetic field produced by the current in the coil. The valve characteristics needed for the IPPT application require a fast-acting valve capable of a minimum of 10(exp 10) valve actuation cycles. Since

  20. Dose-Dependent Thresholds of 10-ns Electric Pulse Induced Plasma Membrane Disruption and Cytotoxicity in Multiple Cell Lines

    Science.gov (United States)

    2011-01-01

    SJ, Fox PM, Rec LJ, Somers K, Stark RH, et al. (2002) Nanosecond Pulsed Electric Field (nsPEF) Effects on Cells and Tissues: Apoptosis Induction and...and a case report of intense nanosecond pulsed electric field as a local therapy for human malignancies. Int J Cancer 121: 675–682. 22. Nuccitelli R...Chen X, Pakhomov AG, Baldwin WH, Sheikh S, et al. (2009) A new pulsed electric field therapy for melanoma disrupts the tumor’s blood supply and causes

  1. Laser ablation of titanium in liquid in external electric field

    Energy Technology Data Exchange (ETDEWEB)

    Serkov, A.A. [Wave Research Center of A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation); The Federal State Educational Institution of Higher Professional Education, “Moscow Institute of Physics and Technology (State University)”, 9 Institutskiy per., 141700, Dolgoprudny, Moscow Region (Russian Federation); Barmina, E.V., E-mail: barminaev@gmail.com [Wave Research Center of A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation); Shafeev, G.A. [Wave Research Center of A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), 31, Kashirskoye Highway, 115409 Moscow (Russian Federation); Voronov, V.V. [A.M. Prokhorov General Physics Institute of the Russian Academy of Sciences, 38, Vavilov Street, 119991 Moscow (Russian Federation)

    2015-09-01

    Highlights: • Ablation of a bulk Ti target by 10 ps laser pulses in liquid is experimentally studied in external DC electric field. • Applied cathodic bias leads to increase in average size of self-organized nanostructures formed upon ablation of titanium target. • Laser ablation of Ti target in external electric field results in generation of elongated titanium oxide nanoparticles. - Abstract: Ablation of a bulk Ti target by 10 ps laser pulses in water is experimentally studied in external DC electric field. It is demonstrated that both lateral size of nanostructures (NS) on Ti surface and their density depend on the electric field applied to the target. Scanning Electron Microscopy of NS reveals the shift of their size distribution function toward larger sizes with applied field (cathodic bias, 25 V DC). Density of mushroom-like NS with applied electric field amounts to 10{sup 10} cm{sup −2}. X-ray diffraction of generated nanoparticles (NPs) shows difference in the crystallographic structure of NPs of non-stoichiometric Ti oxides generated with and without electric field. This conclusion is corroborated with the optical absorption spectroscopy of obtained colloids. Transmission Electron Microscopy of NPs also shows difference in morphology of particles produced with and without cathodic bias. The results are interpreted on the basis of instability of the melt on Ti surface in the electric field.

  2. Nanopore formation in neuroblastoma cells following ultrashort electric pulse exposure

    Science.gov (United States)

    Roth, Caleb C.; Payne, Jason A.; Wilmink, Gerald J.; Ibey, Bennett L.

    2011-03-01

    Ultrashort or nanosecond electrical pulses (USEP) cause repairable damage to the plasma membranes of cells through formation of nanopores. These nanopores are able to pass small ions such as sodium, calcium, and potassium, but remain impermeable to larger molecules like trypan blue and propidium iodide. What remains uncertain is whether generation of nanopores by ultrashort electrical pulses can inhibit action potentials in excitable cells. In this paper, we explored the sensitivity of excitable cells to USEP using Calcium Green AM 1 ester fluorescence to measure calcium uptake indicative of nanopore formation in the plasma membrane. We determined the threshold for nanopore formation in neuroblastoma cells for three pulse parameters (amplitude, pulse width, and pulse number). Measurement of such thresholds will guide future studies to determine if USEP can inhibit action potentials without causing irreversible membrane damage.

  3. Electrohydrodynamic deformation of capsules in electric field

    Science.gov (United States)

    Das, Sudip; Thaokar, Rochish

    2016-11-01

    Micron size capsules are abundant in natural, technological and biological processes but they still require extensive investigation for better understanding of their mechanical behavior. A spherical capusle containing a Newtonian fluid bounded by a viscoelastic membrane and immersed in another Newtonian fluid, and subject to electric field is considered. Discontinuity of electrical properties such as conductivity and permittivity leads to a net Maxwell stress at the capsule interface. In response the capsule undergoes elastic deformation, leading to strain fields and elastic stresses that can balance the applied forces. We investigate this problem with fully resolved hydrodynamics in the