Low-strength Electric Field Research Articles

Electrochemical remediation of phenol contaminated kaolin under low-strength electric fields

Soil degradation is a global concern. Electrochemical remediation (ER) technology is considered an appealing strategy for soil remediation because it is a low-cost, adaptable, and effective noninvasive in situ technology. Currently, the remediation of soil characterized by fine grains, low-hydraulic permeability, heterogeneous conditions, and mixtures of contaminants is still challenging since other conventional technologies are poorly effective. ER of soil is based on the application of low potentials between a couple of electrodes which induces an electric field (E) in the contaminated field. In this work, very low values of electric field (E≤ 0.25 V cm−1) were used for the ER of contaminated kaolin. Phenol was selected as model hazardous organic compound and kaolin as model, reproducible and low buffering and low permeability clay. The effect of several factors, including the nature of the electrodes, treatment time, kind of current, the strength of the E and the nature of supporting electrolyte, on the performance of the process was investigated in detail and discussed in terms of the normalized phenol concentration and its total removal from the kaolin. Overall, the main finding is that the use of very low value of E (0.15 V cm−1) can allow to simultaneously desorb, mobilize and also in-situ degrade phenol. The highest removals of phenol up to approximately 80% and 90% from the kaolin under both direct and sinusoidal E, respectively, were reached using compact graphite as electrodes in presence of Na2SO4 into the kaolin.

The electric field changes the anomalous properties of the Mercedes Benz water model.

The influence of a homogeneous constant electric field on water properties was assessed. We used a simple two-dimensional statistical mechanical model called the Mercedes-Benz (MB) model of water in the study. The MB water molecules are two-dimensional disks with Gaussian arms that mimic the formation of hydrogen bonds. The model is modified with added charges for interaction with the electric field. The influence of the strength of the electric field on the water's properties was studied using Monte Carlo simulations. The structure and thermodynamics of the water were determined as a function of the strength of the electric field. We observed that the properties and phase transitions of the water in the low strength electric field does not change. In contrast, the high strength electric field shifts boiling and melting points as well as the position of the density maxima. After further increasing the strength of the electric field the density anomaly disappears.

The morphology and the electro-optical properties of PDLCs cured in the presence of electric fields

ABSTRACT Polymer dispersed liquid crystals, PDLCs, are composite materials generally formed by spherical liquid crystal droplets embedded in a polymer matrix. Reports of PDLCs with different droplet shape are not widespread. In this work, epoxy/LC mixtures in different weight ratios were polymerised in the presence of an external AC electric field with increasing strengths. The morphology and the electro-optical properties of the obtained PDLCs were found to be dependent from the strength of the electric field applied during the curing process. Common PDLCs with spherical droplets were obtained from samples polymerised under the action of low strength electric fields, but PDLCs with elongated droplets and memory states were found for polymerisation performed in the presence of intermediate electric fields. For larger electric fields, PDLCs were characterised by a morphology with long cylindrical channels and large memory states.

Stimulation of polymorphonuclear leukocyte activity under the influence of low strength electric field

It is assumed that electrical stimulation can be the most important physical effect providing regulation of the activity of immune cells such as polymorphonuclear leukocytes (PMNL). To study the effect of electrical stimulation on PMNL activity, the experimental setup based on electric signal generator and biochemiluminometer was developed, which allows performing electrostimulation of cells and studying the generation of reactive oxygen species (ROS) in PMNL simultaneously. Impact on the cells was carried out using electrodes immersed in incubation medium connected to electric signal generator. Non-uniform electric field was established, the intensity of which decreased with distance and time that imitated the characteristics of endogenous electric fields in places of inflammation in organism. During stimulation, the field strength was low, up to 1 V/cm. It was found that as a result of electrical stimulation, a change in the functional capabilities of human blood PMNL is observed. The severity of effects depends on the voltage applied to the electrodes and the duration of the observation. The key functional processes in PMNL such as ROS generation and myeloperoxidase enzyme secretion are enhanced in the initial period of electric field influence. A few hours after electrical stimulation, inhibition of PMNL activity and the gradual destruction of cells are observed. The obtained data testify the regulatory role of electrical stimulation in relation to PMNL activity which necessary for the implementation of the bodyʼs immune defense.

Enhancement of single-walled carbon nanotube accumulation in glioma cells exposed to low-strength electric field: Promising approach in cancer nanotherapy

The objective of the study is to determine the patterns of regulation of single-walled carbon nanotube accumulation, distribution, and agglomeration in glioma cells exposed to an external electric field. C6 glioma cells were treated with 5 μg/ml DNA wrapped single-walled carbon nanotubes and exposed to bi-phasic electric pulses (6.6 V/m, 200 Hz, pulse duration 1 ms). Nanotube accumulation was determined by Raman microspectroscopy and their intracellular local concentration was evaluated using the G-band intensity in Raman spectra of single-walled carbon nanotubes. It was revealed that the low-frequency and low-strength electric field stimulation of glioma cells exposed to single-walled carbon nanotubes led to facilitation and, thus, to amplification of nanotube accumulation inside the cells. The number of nanotubes in intracellular agglomerates increased from (28.8 ± 13.1) un./agglom. and (84.0 ± 28.7) un./agglom. in control samples to (60.6 ± 21.4) un./agglom. and (184.2 ± 53.4) un./agglom. for 1 h and 2 h stimulation, respectively. Thus, the tumor exposure to an external electric field makes it possible to more effectively regulate the accumulation and distribution of carbon nanotubes inside glioma cells allowing to reduce the applied therapeutic doses of carbon nanomaterial delivered anticancer drugs.

Electric field measurement of two commercial active/sham coils for transcranial magnetic stimulation

Objective. Sham TMS coils isolate the ancillary effects of their active counterparts but typically induce low-strength electric fields (E-fields) in the brain, which could be biologically active. We measured the E-fields induced by two pairs of commonly-used commercial active/sham coils. Approach. E-field distributions of the active and sham configurations of the Magstim 70 mm AFC and MagVenture Cool-B65 A/P coils were measured over a 7 cm-radius, hemispherical grid approximating the cortical surface. Peak E-field strength was recorded over a range of pulse amplitudes. Main results. The Magstim and MagVenture shams induce peak E-fields corresponding to 25.3% and 7.72% of their respective active values. The MagVenture sham has an E-field distribution shaped like its active counterpart. The Magstim sham induces nearly zero E-field under the coil’s center, and its peak E-field forms a diffuse oval 3–7 cm from the center. Electrical scalp stimulation paired with the MagVenture sham is estimated to increase the sham E-field in the brain up to 10%. Significance. Different commercial shams induce different E-field strengths and distributions in the brain, which should be considered in interpreting outcomes of sham stimulation.

Measuring ultrafine aerosols by direct photoionization and charge capture in continuous flow

Direct ultraviolet (UV) photoionization enables electrical charging of aerosol nanoparticles without relying on the collision of particles and ions. In this work, a low-strength electric field is a...

Hydrophilic quantum dots stability against an external low-strength electric field

Since the stability of nanobiolabels plays a key role in their application, we thoroughly investigated how an external, low-strength electric field impacts on the fluorescent properties of hydrophilic quantum dots (QDs). Two fundamentally different approaches were applied to make the QDs water-soluble, i.e. ligand exchange (namely silica covering) and encapsulation with an amphiphilic polymer. It is shown that, even under a low-strength electric field, the polymer-coated QDs could lose 90% of their brightness because of the weak interaction between the QD's surface and the polymeric molecule. Silica-covered QDs, on the contrary, stay bright and stable owing to the covalently attached dense silica shell. These findings, which are clearly explained and illustrated in the present paper, are of critical importance in the context of hydrophilic QDs’ bioapplication.

Electric field induced ultra-high actuation in a bulk carbon nanotube structure

Electric-field induced nonlinear actuation behavior is demonstrated in a bulk nanotube (CNT) structure under ambient conditions. Completely recoverable and non-degradable actuation over several cycles of electric-field is measured in these structures. A symmetric and polarity independent displacement corresponding up to an axial strain of 14% is measured upon application of a low strength electric field of 4.2kV/m in the axial direction. However, a much lower strain of ∼1% is measured in the radial (or, transverse) direction. Furthermore, the electric field induced actuation increases by more than a factor of 2 upon impregnating the CNT cellular structure with copper oxide nano-particles. An electrostriction mechanism, based on the electric-field induced polarization of CNT strands, is proposed to account for the reported actuation behavior.

Electrokinetic transport of aerobic microorganisms under low-strength electric fields

To investigate the feasibility of utilizing low strength electric fields to transport commonly available mixed cultures such as those from an activated sludge process, bench scale batch reactor studies were conducted in sand and sandy loam soils. A readily biodegradable substrate, dextrose, was used to test the activity of the transported microorganisms. Electric field strengths of 7V, 10.5V, and 14V were used. Results from this investigation showed that an electric field strength of 0.46 Volts per cm was sufficient to transport activated sludge microorganisms across a sandy loam soil across a distance of about 8 cm in 72 h. More importantly, the electrokinetically transported microbial culture remained active and viable after the transport process and was biodegrade 44% of the dextrose in the soil medium. Electrokinetic treatment without microorganisms resulted in removal of 37% and the absence of any treatment yielded a removal of about 15%.

Noncooled Capillary Inlet: A Source of Systematic Errors in Capillary-Electrophoresis-Based Affinity Analyses

Capillary electrophoresis (CE) serves as a platform for a large family of temperature-sensitive affinity methods. To control the electrolyte temperature, the heat generated during electrophoresis is removed by actively cooling the capillary. Short parts of the capillary, particularly at its inlet, are not actively cooled, however, and the electrolyte in this part is likely to be at an elevated temperature. Owing to their relatively short lengths, the noncooled parts have never been considered as a potential source of artifacts. Here we report for the first time that electrophoresis of the sample through the short noncooled capillary inlet can lead to large systematic errors in quantitative CE-based affinity analyses. Our findings suggest that the noncooled capillary inlet region, in spite of being short, is a source of significant artifacts that must be taken into consideration by developers and users of CE-based affinity methods. We propose a simple solution for this problem: moving the sample through the noncooled inlet into the cooled region by pressure or by a low-strength electric field to save it from exposure to the elevated temperature.

106: Low Strength Electric Field Network-Mediated Ex Vivo IL-4 and IL-10 Combined Gene Therapy Induced Rabbit Cardiac Allograft Tolerance

106: Low Strength Electric Field Network-Mediated Ex Vivo IL-4 and IL-10 Combined Gene Therapy Induced Rabbit Cardiac Allograft Tolerance

Electric-Field-Induced Orientation of Surfactant-Templated Nanoscopic Silica

While exhibiting a well-defined nanometer-level structure, surfactant-templated nanoscopic silicas produced via self-assembly do not always possess long-range order. We demonstrate that long-range order can be controlled by guiding the self-assembly of nanostructured silica-surfactant hybrids with low-strength electric fields (E approximately 200 V/m) to produce nanoscopic silica with both the micrometer- and nanometer-level structures oriented parallel to the applied field. Under the influence of the electric field, nanoscopic silica particles migrate, elongate, and merge into fibers with a rate of migration proportional to the applied field strength. The linear dependence with the field strength indicates that the process is governed by electroosmotic flow but not by polarization effects. Realignment of the short-range ordered surfactant nanochannels along the fiber axis accompanies the migration.

Electrical enhancement of biocide efficacy against Pseudomonas aeruginosa biofilms

When applied within a low-strength electric field (+/- 12 V/cm) with a low current density (+/- 2.1 mA/cm2), several industrial biocides exhibited enhanced killing action against Pseudomonas aeruginosa biofilms grown on stainless steel studs. Biocide concentrations lower than those necessary to kill planktonic cells of P. aeruginosa (1, 5, and 10 ppm of the active ingredients of kathon, glutaraldehyde, and quaternary ammonium compound, respectively) were bactericidal within 24 h when applied within our electrified device.

Electric orientation of liquid crystals of poly-γ-benzyl- l-glutamate

The orientation of liquid crystals of poly-γ-benzyl- l-glutamate in low-strength electric fields was studied mainly by the infrared dichroic ratio. 1. 1. A high degree of orientation of liquid crystals of poly-γ-benzyl- l-glutamate in electric fields resulted from the cooperative but very complicated behavior of the polypeptide molecules. 2. 2. In dilute liquid-crystalline solutions, the polypeptide molecules behaved as if independent molecular clusters having a dipole moment some 730 times as large as that of the single polypeptide molecule (of degree of polymerization 650) were present in solution. 3. 3. The polypeptide molecules in liquid-crystalline solution could not achieve perfect orientation owing to the nature of the liquid crystals even if only the birefringent phase existed in solution. 4. 4. Electric current through liquid-crystalline solution was slight, and did not seem to have much effect on the electric orientation.