scholarly journals Investigation of the Electrical Properties of Microtubule Ensembles under Cell-Like Conditions

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 265 ◽  
Author(s):  
Aarat P. Kalra ◽  
Sahil D. Patel ◽  
Asadullah F. Bhuiyan ◽  
Jordane Preto ◽  
Kyle G. Scheuer ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Electrical Resistance ◽  
Charge Storage ◽  
Appreciable Effect ◽  
Low Frequencies ◽  
Storage Devices ◽  
Macromolecular Transport ◽  
Chromosomal Segregation ◽  
State Dependent ◽  
Β Tubulin

Microtubules are hollow cylindrical polymers composed of the highly negatively-charged (~23e), high dipole moment (1750 D) protein α, β- tubulin. While the roles of microtubules in chromosomal segregation, macromolecular transport, and cell migration are relatively well-understood, studies on the electrical properties of microtubules have only recently gained strong interest. Here, we show that while microtubules at physiological concentrations increase solution capacitance, free tubulin has no appreciable effect. Further, we observed a decrease in electrical resistance of solution, with charge transport peaking between 20–60 Hz in the presence of microtubules, consistent with recent findings that microtubules exhibit electric oscillations at such low frequencies. We were able to quantify the capacitance and resistance of the microtubules (MT) network at physiological tubulin concentrations to be 1.27 × 10−5 F and 9.74 × 104 Ω. Our results show that in addition to macromolecular transport, microtubules also act as charge storage devices through counterionic condensation across a broad frequency spectrum. We conclude with a hypothesis of an electrically tunable cytoskeleton where the dielectric properties of tubulin are polymerisation-state dependent.

STUDYING MULTILAYERED GRAPHENES BY ELECTROPHYSICAL METHODS

2021 ◽  
pp. 100-107
Author(s):  
K. L. Levine ◽  
D. V. Ryabokon ◽  
S. D. Khanin ◽  
R. V. Gelamo ◽  
N. A. Nikonorova
Keyword(s):  
Electrical Conductivity ◽  
Chemical Composition ◽  
Electrical Properties ◽  
Work Function ◽  
Electron Work Function ◽  
Charge Storage ◽  
High Electrical Conductivity ◽  
Free Standing ◽  
Storage Devices

The paper studies multilayer graphenes in the form of free-standing films. The authors provide data about the morphology and electrical properties of films treated with plasma of various chemical composition. It is shown that it is possible to control the electrical properties of the surface and electron work function without significantly affecting its morphology. The obtained samples, combining mechanical flexibility with unreactiveness and high electrical conductivity, are promising for application in flexible charge storage devices.

scholarly journals RDNA-01. TUBULIN AND MICROTUBULES AS MOLECULAR TARGETS FOR TTFIELD THERAPY

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi207-vi207
Author(s):  
Aarat Kalra ◽  
Sahil Patel ◽  
Asadullah Bhuiyan ◽  
Vahid Rezania ◽  
John Lewis ◽  
...  
Keyword(s):  
Electric Fields ◽  
Molecular Targets ◽  
Intermediate Frequency ◽  
Recurrent Glioblastoma ◽  
Charge Storage ◽  
Appreciable Effect ◽  
Recurrent Glioblastoma Multiforme ◽  
Storage Devices ◽  
Ac Electric Fields ◽  
A Cell

Abstract TTField (Tumor-treating field) therapy utilizes low intensity intermediate frequency AC electric fields to reduce the spread of cancer. While it has attained FDA approval for the treatment of recurrent glioblastoma multiforme, the exact molecular targets of TTField therapy are not well understood. Microtubules are pipe-like polymers of the highly charged (–31 e) and strongly dipolar (dipole moment 1666 D) protein, α, β- tubulin. Studies on the electrical properties of microtubules have recently gained interest, with them being modelled as molecular targets of TTFields. Here, we experimentally show that while tubulin polymerized into microtubules leads to an increase in solution capacitance, unpolymerized tubulin has no appreciable effect. To the best of our knowledge, we present the first experimental quantification of the capacitance of a 20 μm-long microtubule. Using these results, we calculate the resonant frequency of a microtubule meshwork in a cell-like environment to be in the TTField regime. Our results utilize high ionic strength solutions and cell-like concentrations of tubulin to show the potential of microtubules as the targets of TTField action and as intracellular charge-storage devices. We conclude with a hypothesis of an electrically-tunable cell, where the dielectric properties of the cytoskeleton alter local and global charge storage and transport.

scholarly journals Electrical properties of graphenes for application in electrochemical charge storage devices

2019 ◽  
Author(s):  
Kirill Lvovich Levin ◽  
Rojerio V. Jelamo ◽  
Nikolay S. Pshchelko ◽  
Samuil D. Khanin
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Energy Storage ◽  
Electrical Properties ◽  
Electric Energy ◽  
Charge Storage ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Electric Energy Storage ◽  
Different Types

Graphenes in the form of flexible thin films treated with different types of plasma were investigated by Mott-Schottky analysis. The possibility of variation of electrical conductivity in graphene prepared by plasma treatment was shown. Obtained materials are promising for electric energy storage devices.

Linear electrical properties of striated muscle fibres observed with intracellular electrodes

1964 ◽  
Vol 160 (978) ◽  
pp. 69-123 ◽  
Keyword(s):  
Electrical Properties ◽  
Striated Muscle ◽  
Surface Membrane ◽  
Fibre Surface ◽  
Step Function ◽  
Muscle Fibres ◽  
Appreciable Effect ◽  
Current Application ◽  
Current Path ◽  
Wide Range

The linear electrical properties of muscle fibres have been examined using intracellular electrodes for a. c. measurements and analyzing observations on the basis of cable theory. The measurements have covered the frequency range 1 c/s to 10 kc/s. Comparison of the theory for the circular cylindrical fibre with that for the ideal, one-dimensional cable indicates that, under the conditions of the experiments, no serious error would be introduced in the analysis by the geometrical idealization. The impedance locus for frog sartorius and crayfish limb muscle fibres deviates over a wide range of frequencies from that expected for a simple model in which the current path between the inside and the outside of the fibre consists only of a resistance and a capacitance in parallel. A good fit of the experimental results on frog fibres is obtained if the inside-outside admittance is considered to contain, in addition to the parallel elements R m = 3100 Ωcm 2 and C m = 2.6 μF/cm 2 , another path composed of a resistance R e = 330 Ωcm 2 in series with a capacitance C e = 4.1 μF/cm 2 , all referred to unit area of fibre surface. The impedance behaviour of crayfish fibres can be described by a similar model, the corresponding values being R m = 680 Ωcm 2 , C m = 3.9 μF/cm 2 , R e = 35 Ωcm 2 , C e = 17 μF/cm 2 . The response of frog fibres to a step-function current (with the points of voltage recording and current application close together) has been analyzed in terms of the above two-time constant model, and it is shown that neglecting the series resistance would have an appreciable effect on the agreement between theory and experiment only at times less than the halftime of rise of the response. The elements R m and C m are presumed to represent properties of the surface membrane of the fibre. R e and C e are thought to arise not at the surface, but to be indicative of a separate current path from the myoplasm through an intracellular system of channels to the exterior. In the case of crayfish fibres, it is possible that R e (when referred to unit volume) would be a measure of the resistivity of the interior of the channels, and C e the capacitance across the walls of the channels. In the case of frog fibres, it is suggested that the elements R e , C e arise from the properties of adjacent membranes of the triads in the sarcoplasmic reticulum . The possibility is considered that the potential difference across the capacitance C e may control the initiation of contraction.

scholarly journals Ionic Liquids in Charge Storage Devices: Effect of Purification on Performance

10.5772/23870 ◽  
2011 ◽  
Author(s):  
John D. ◽  
Andrew P. ◽  
Clare F. Kline Jr. ◽  
Gregory S. ◽  
Roxanne L.
Keyword(s):  
Ionic Liquids ◽  
Charge Storage ◽  
Storage Devices

scholarly journals Вплив параметрів адитивного формування на електричні властивості графітонаповненого композиту на основі полілактиду

2021 ◽  
Vol 150 (5) ◽  
pp. 93-102
Author(s):  
Н. В. Сова ◽  
О. О. Слепцов ◽  
Т. Р. Федорів ◽  
А. О. Мартиненко ◽  
М. Р. Кудлай ◽  
...  
Keyword(s):  
Electrical Properties ◽  
3D Printing ◽  
Electrical Resistance ◽  
Specific Resistance ◽  
Polymer Melt ◽  
Electrical Characteristics ◽  
Additive Production ◽  
Filled Composite ◽  
Printing Parameters ◽  
Bulk Electrical Resistance

Purpose. Investigate the effect of additive formation parameters on the properties of an antistatic composition based on polylactide (PLA). Methodology. Surface and bulk electrical resistance were determined by ASTM D257. Findings. The influence of additive formation parameters on the electrical properties of graphite-filled composite based on polylactide has been studied. It was found that the value of resistivity significantly depends on the printing conditions, namely the temperature, speed, thickness of the layer. Increasing the printing temperature helps to reduce the resistivity of the sample. Reducing the thickness of the polymer layer also reduces the resistivity at a print speed within 3000 mm / min It was found that the specific electrical characteristics are significantly different in the plane of the sample in contact with the printing platform. Concentric method of laying layers of polymer melt is less effective in terms of resistivity than mutually perpendicular. It was found that the electrical resistivity of samples made of material for 3D printing, which was previously subjected to drying below the resistance of the sample made of undried material. The programmed change of 3D printing parameters allows to control the specific resistance of graphite-filled composite based on polylactide in the range of three orders and to obtain products with properties from antistatic to statically dissipative materials. Additive production allows to obtain products of the desired configuration with adjustable electrical properties. Originality. The peculiarities of the change of antistatic properties of the polymer composite depending on the conditions of additive formation of experimental samples are investigated. Depending on the applied parameters of additive molding, it is possible to obtain products with properties from antistatic to statically dissipative materials. Practical value. Technological modes of additive molding of composite products based on polylactide and graphite have been developed. Energy consumption for additive formation of products of different mass is estimated.

scholarly journals The influence of multifunctional microalloyed ceramics microstructure on its capacity properties

2018 ◽  
Vol 15 (2) ◽  
pp. 187-199
Author(s):  
Jelena Purenovic ◽  
Nedeljko Ducic ◽  
Branko Matovic ◽  
Milovan Purenovic
Keyword(s):  
Crystal Structure ◽  
Dielectric Constant ◽  
Electrical Properties ◽  
Electrical Resistance ◽  
Ceramic Materials ◽  
Porous Ceramics ◽  
Electrophysical Properties ◽  
Microstructural Properties ◽  
Structure Morphology ◽  
Composition Structure

Modified porous alumo-silicate ceramics, alloyed with magnesium and microalloyed with aluminum, belongs to modern multifunctional ceramic materials. Microalloying has led to important changes in dielectric and electrical properties of ceramics, such as dielectric constant and electrical resistance. These changes are conditioned by the microstructural properties of modified porous ceramics. The obtained results have shown the unity of the influence of composition, structure, morphology and application of microalloyed multifunctional alumosilicate ceramics on electrophysical properties. Microstructural investigations have shown that this type of ceramics has an amorphous-crystal structure, which causes important changes in its electrical properties and affects its activity. Therefore the ceramics can be considered as an active dielectric. A correlation between microstructural properties and structurally sensitive, i.e. electrophysical properties of microalloyed multifunctional alumo-silicate ceramics, was confirmed.

Polyaniline Nanocomposites

2019 ◽  
pp. 220-253 ◽  
Author(s):  
Dipanwita Majumdar
Keyword(s):  
Energy Storage ◽  
Cost Effective ◽  
Future Generation ◽  
Charge Storage ◽  
Energy Storage Devices ◽  
High Quality ◽  
Storage Devices ◽  
Effective Synthesis ◽  
Nano Carbon ◽  
Hand Assistance

Polyaniline in various forms has been widely explored as an electrode material for supercapacitors due to its high theoretical charge storage capacity, facile-cost-effective synthesis, good mechanical strength and ultrafast charge transport. However, commercialization of such pristine forms is very much restricted by low solubilities, rapid agglomeration during device design accompanied by poor electrochemical life and fast environmental decomposition. The blending with nano-carbon materials, metal oxides and other competent materials, may result in high quality materials– “nanocomposites” with superior features is ideally fit for future generation energy storage devices. The present chapter deals with detailed discussions on designing, the fabrication of such binary and ternary nanocomposites, correlating their morphology with electrochemical behavior, so as to optimize their supercapacitive performances. Such an attempt would help to outline the present status and future aspects of these materials which will be of first-hand assistance especially to the beginners to this field of research.

scholarly journals Structural and Electrical Studies for Birnessite-Type Materials Synthesized by Solid-State Reactions

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1156 ◽  
Author(s):  
Nayda P. Arias ◽  
María E. Becerra ◽  
Oscar Giraldo
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Nitrogen Adsorption ◽  
Synthesis Temperature ◽  
Thermal Reduction ◽  
Solid State Reactions ◽  
Low Frequencies ◽  
Structural Formulas ◽  
Interlayer Region ◽  
Adsorption Desorption

The focus of this paper is centered on the thermal reduction of KMnO4 at controlled temperatures of 400 and 800 °C. The materials under study were characterized by atomic absorption spectroscopy, thermogravimetric analysis, average oxidation state of manganese, nitrogen adsorption–desorption, and impedance spectroscopy. The structural formulas, found as a result of these analyses, were K 0.29 + ( M n 0.84 4 + M n 0.16 3 + ) O 2.07 · 0.61 H 2 O and K 0.48 + ( M n 0.64 4 + M n 0.36 3 + ) O 2.06 · 0.50 H 2 O . The N2 adsorption–desorption isotherms show the microporous and mesoporous nature of the structure. Structural analysis showed that synthesis temperature affects the crystal size and symmetry, varying their electrical properties. Impedance spectroscopy (IS) was used to measure the electrical properties of these materials. The measurements attained, as a result of IS, show that these materials have both electronic and ionic conductivity. The conductivity values obtained at 10 Hz were 4.1250 × 10−6 and 1.6870 × 10−4 Ω−1cm−1 for Mn4 at 298 and 423 K respectively. For Mn8, the conductivity values at this frequency were 3.7074 × 10−7 (298) and 3.9866 × 10−5 Ω−1cm−1 (423 K). The electrical behavior was associated with electron hopping at high frequencies, and protonic conduction and ionic movement of the K+ species, in the interlayer region at low frequencies.

scholarly journals Stretchable batteries with gradient multilayer conductors

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw1879 ◽  
Author(s):  
Minsu Gu ◽  
Woo-Jin Song ◽  
Jaehyung Hong ◽  
Sung Youb Kim ◽  
Tae Joo Shin ◽  
...  
Keyword(s):  
Self Assembly ◽  
Multiple Scales ◽  
Discharge Rate ◽  
Rate Capability ◽  
Lithium Ion ◽  
Charge Storage ◽  
Storage Devices ◽  
Essential Components ◽  
Stretchable Conductors ◽  
A Charge

Stretchable conductors are essential components in next-generation deformable and wearable electronic devices. The ability of stretchable conductors to achieve sufficient electrical conductivity, however, remains limited under high strain, which is particularly detrimental for charge storage devices. In this study, we present stretchable conductors made from multiple layers of gradient assembled polyurethane (GAP) comprising gold nanoparticles capable of self-assembly under strain. Stratified layering affords control over the composite internal architecture at multiple scales, leading to metallic conductivity in both the lateral and transversal directions under strains of as high as 300%. The unique combination of the electrical and mechanical properties of GAP electrodes enables the development of a stretchable lithium-ion battery with a charge-discharge rate capability of 100 mAh g−1 at a current density of 0.5 A g−1 and remarkable cycle retention of 96% after 1000 cycles. The hierarchical GAP nanocomposites afford rapid fabrication of advanced charge storage devices.

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