scholarly journals Effects of Specific Electric Field Stimulation on the Release and Activity of Secreted Acid Phosphatases from Leishmania tarentolae and Implications for Therapy

Pathogens ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 77 ◽  
Author(s):  
Benjamin Dorsey ◽  
Cynthia Cass ◽  
David Cedeño ◽  
Ricardo Vallejo ◽  
Marjorie Jones
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Field Application ◽  
Kinetic Constants ◽  
Sand Fly ◽  
Field Stimulation ◽  
Acid Phosphatases ◽  
Cell Secretion ◽  
Leishmania Tarentolae ◽  
Enzyme Isoforms

Leishmaniasis is a neglected tropical disease with 1.6 million new cases reported each year. However, there are few safe, effective, and affordable treatments provided to those affected by this disease. Still under-appreciated as potential pharmaceutical targets, especially for cutaneous leishmaniasis infections, are the two isozymes of secreted acid phosphatase (SAP). These enzymes are involved in the survival of the parasite in the sand fly vector, and in infecting host macrophages. While the application of electric or electromagnetic fields as a medicinal therapeutic is not new, the utility of electric field application for the treatment of leishmaniasis is under studied. Studies involving the effects of electric fields on the cell secretion of SAP or the activity of SAP that has been secreted prior to electrical stimulation have not yet been reported. This work is the first report on the effect of specific electric fields on the activity of Leishmania tarentolae secreted acid phosphatases and the modulation of this secretion from the cells. In addition, the kinetic constants for the enzyme isoforms were determined as a function of days in culture and removal of carbohydrate from the glycosylated enzymes, while using a glycosidase, was shown to affect these kinetic constants.

scholarly journals Effect of combining sleep-promoting food intake and electric field application on sleep in healthy participants: A pilot study

2021 ◽  
Vol 11 (12) ◽  
pp. 659
Author(s):  
Takaki Nedachi ◽  
Kaoru Haketa ◽  
Shinji Harakawa ◽  
Naoki Miura ◽  
Koji Wakame
Keyword(s):  
Food Intake ◽  
Electric Field ◽  
Sleep Quality ◽  
Electric Fields ◽  
Functional Foods ◽  
Field Application ◽  
Stress Effect ◽  
Gamma Aminobutyric Acid ◽  
Healthy Participants ◽  
Food Mixture

Background: Functional foods and electric fields (EFs) have been previously reported as interventions for insomnia other than medications. As for functional foods, gamma-aminobutyric acid (GABA) and lafma have been reported to be related to sleep. EFs have also been reported to have a sleep-related, anti-stress effect in mouse model experiments. However, the effects of combining these two methods on the human body remain poorly studied. Objective: Thus, this study aimed to investigate the cointervention effect of sleep-promoting functional food intake and EF application on sleep quality in healthy participants. Methods: Fifteen healthy participants were divided into three groups. The Food and Placebo groups were given active tablets containing food mixture of GABA and lafma, and placebo tablets, respectively, for 4 weeks. Meanwhile, the Food plus EF group used an EF therapy device during sleep in addition to the active food tablets. Sleep quality was evaluated using electroencephalography and sleep questionnaires.Results: Sleep efficiency (SE) was significantly higher in the Food group and the Food plus EF group than the Placebo group at 4 weeks. The Food plus EF group also had a significantly higher SE involving sleep latency. Conclusions: Food mixture containing known sleep-promoting ingredients such as GABA and lafma can improve sleep quality, and the improvement effect can be enhanced when administered in combination with an EF.Keywords: electric field therapy, Kumasasa (Sasa senanensis), electric fields, sleep quality, electroencephalographyClinical trial registration: Approval No.: R1812; Approval date: 21 Feb. 2019

scholarly journals Electric field stimulation for tissue engineering applications

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Christina N. M. Ryan ◽  
Meletios N. Doulgkeroglou ◽  
Dimitrios I. Zeugolis
Keyword(s):  
Tissue Engineering ◽  
Wound Healing ◽  
Electric Field ◽  
Electric Fields ◽  
Cell Types ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Physiological Processes ◽  
Different Cell Types

AbstractElectric fields are involved in numerous physiological processes, including directional embryonic development and wound healing following injury. To study these processes in vitro and/or to harness electric field stimulation as a biophysical environmental cue for organised tissue engineering strategies various electric field stimulation systems have been developed. These systems are overall similar in design and have been shown to influence morphology, orientation, migration and phenotype of several different cell types. This review discusses different electric field stimulation setups and their effect on cell response.

Confirmation of no Structural and Chemical Changes in Curie Temperature Variable Co Ultrathin Films by Electric Field

2016 ◽  
Vol 230 (4) ◽  
Author(s):  
Yusuke Wakabayashi ◽  
Hiromasa Fujii ◽  
Tsuyoshi Kimura ◽  
Osami Sakata ◽  
Hiroo Tajiri ◽  
...  
Keyword(s):  
Curie Temperature ◽  
Electric Field ◽  
Electric Fields ◽  
Ultrathin Films ◽  
Applied Voltage ◽  
Large Change ◽  
Field Application ◽  
X Ray ◽  
Reflectivity Signal ◽  
Temperature Variable

AbstractA cobalt ultrathin film, which shows a large change in Curie temperature by an electric field application, has been studied by x-ray reflectometry with applying electric fields. The cobalt film was made by the sputtering method on top of a Pt buffer layer, and capped with a MgO layer. X-ray reflectometry shows that the change in Co thickness caused by the applied voltage up to ±10 V was less than 0.06 Å. The reflectivity signal intensity shows a characteristic kink at the Co

scholarly journals Ih interacts with somato-dendritic structure to determine frequency response to weak alternating electric field stimulation

2018 ◽  
Vol 119 (3) ◽  
pp. 1029-1036 ◽  
Author(s):  
Enrique H. S. Toloza ◽  
Ehsan Negahbani ◽  
Flavio Fröhlich
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Cellular Response ◽  
Current Injection ◽  
Field Stimulation ◽  
Electric Field Stimulation ◽  
Cation Current ◽  
Network Oscillations ◽  
Alternating Electric Field

Transcranial current stimulation (tCS) modulates brain dynamics using weak electric fields. Given the pathological changes in brain network oscillations in neurological and psychiatric illnesses, using alternating electric field waveforms that engage rhythmic activity has been proposed as a targeted, network-level treatment approach. Previous studies have investigated the effects of electric fields at the neuronal level. However, the biophysical basis of the cellular response to electric fields has remained limited. Here, we characterized the frequency-dependent response of different compartments in a layer V pyramidal neuron to exogenous electric fields to dissect the relative contributions of voltage-gated ion channels and neuronal morphology. Hyperpolarization-activated cation current (Ih) in the distal dendrites was the primary ionic mechanism shaping the model’s response to electric field stimulation and caused subthreshold resonance in the tuft at 20 ± 4 Hz. In contrast, subthreshold Ih-mediated resonance in response to local sinusoidal current injection was present in all model compartments at 11 ± 2 Hz. The frequencies of both resonance responses were modulated by Ih conductance density. We found that the difference in resonance frequency between the two stimulation types can be explained by the fact that exogenous electric fields simultaneously polarize the membrane potentials at the distal ends of the neuron (relative to field direction) in opposite directions. Our results highlight the role of Ih in shaping the cellular response to electric field stimulation and suggest that the common model of tCS as a weak somatic current injection fails to capture the cellular effects of electric field stimulation. NEW & NOTEWORTHY Modulation of cortical oscillation by brain stimulation serves as a tool to understand the causal role of network oscillations in behavior and is a potential treatment modality that engages impaired network oscillations in disorders of the central nervous system. To develop targeted stimulation paradigms, cellular-level effects must be understood. We demonstrate that hyperpolarization-activated cation current (Ih) and cell morphology cooperatively shape the response to applied alternating electric fields.

scholarly journals Excitatory effect of biphasic kHz field stimulation on CA1 pyramidal neurons in slices

2021 ◽  
Author(s):  
Sergei Karnup ◽  
William C. DeGroat ◽  
Jonathan M. Beckel ◽  
Changfeng Tai
Keyword(s):  
Electric Fields ◽  
Brain Slice ◽  
Pyramidal Neurons ◽  
Field Application ◽  
Neuronal Membrane ◽  
Field Stimulation ◽  
Spontaneous Firing ◽  
Excitatory Effect ◽  
Glutamatergic Synaptic Transmission ◽  
Inhibitory Synaptic Input

Background: Electrical stimulation in the kilohertz-frequency range has been successfully used for treatment of various neurological disorders. Nevertheless, the mechanisms underlying this stimulation are poorly understood. Objective: To study the effect of kilohertz-frequency electric fields on neuronal membrane biophysics we developed a reliable experimental method to measure responses of single neurons to kilohertz field stimulation in brain slice preparations. Methods: In the submerged brain slice pyramidal neurons of the CA1 subfield were recorded in the whole-cell configuration before, during and after stimulation with an external electric field at 2kHz, 5kHz or 10 kHz. Results: Reproducible excitatory changes in rheobase and spontaneous firing were elicited during kHz-field application at all stimulating frequencies. The rheobase only decreased and spontaneous firing either was initiated in silent neurons or became more intense in previously spontaneously active neurons. Response thresholds were higher at higher frequencies. Blockade of glutamatergic synaptic transmission did not alter the magnitude of responses. Inhibitory synaptic input was not changed by kilohertz field stimulation. Conclusion: kHz-frequency current applied in brain tissue has an excitatory effect on pyramidal neurons during stimulation. This effect is more prominent and occurs at a lower stimulus intensity at a frequency of 2kHz as compared to 5kHz and 10kHz.

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

scholarly journals Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 107
Author(s):  
Haichao Yu ◽  
Feng Tang ◽  
Jingjun Wu ◽  
Zao Yi ◽  
Xin Ye ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Laser Cutting ◽  
High Complexity ◽  
Damage Potential ◽  
Optical Components ◽  
Nanohole Arrays ◽  
Intense Light ◽  
Polarization Of Light ◽  
Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

scholarly journals Integrating flexible electronics for pulsed electric field delivery in a vascularized 3D glioblastoma model

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Marie C. Lefevre ◽  
Gerwin Dijk ◽  
Attila Kaszas ◽  
Martin Baca ◽  
David Moreau ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Flexible Electronics ◽  
Soft Tissues ◽  
Multiphoton Microscopy ◽  
Membrane Integrity ◽  
Tumor Model ◽  
Pulsed Electric Fields ◽  
In Ovo ◽  
Cell Membrane Integrity

AbstractGlioblastoma is a highly aggressive brain tumor, very invasive and thus difficult to eradicate with standard oncology therapies. Bioelectric treatments based on pulsed electric fields have proven to be a successful method to treat cancerous tissues. However, they rely on stiff electrodes, which cause acute and chronic injuries, especially in soft tissues like the brain. Here we demonstrate the feasibility of delivering pulsed electric fields with flexible electronics using an in ovo vascularized tumor model. We show with fluorescence widefield and multiphoton microscopy that pulsed electric fields induce vasoconstriction of blood vessels and evoke calcium signals in vascularized glioblastoma spheroids stably expressing a genetically encoded fluorescence reporter. Simulations of the electric field delivery are compared with the measured influence of electric field effects on cell membrane integrity in exposed tumor cells. Our results confirm the feasibility of flexible electronics as a means of delivering intense pulsed electric fields to tumors in an intravital 3D vascularized model of human glioblastoma.

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