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Biofiltration is a simple and low-cost method for the cleanup of contaminated water. However, the reduced availability of dissolved chemicals to surface-attached degrader bacteria may limit its efficient use at certain hydraulic loadings. When a direct current (DC) electric field is applied to an immersed packed bed, it invokes electrokinetic processes, such as electroosmotic water flow (EOF). EOF is a surface-charge-induced plug-flow-shaped movement of pore fluids. It acts at a nanometer distance above surfaces and allows the change of microscale pressure-driven flow profiles and, hence, the availability of dissolved contaminants to microbial degraders. In laboratory percolation columns, we assessed the effects of a weak DC electric field ( E = 0.5 V·cm -1 ) on the biodegradation of waterborne naphthalene (NAH) by surface-attached Pseudomonas fluorescens LP6a. To vary NAH bioavailability, we used different NAH concentrations ( C 0 = 2.7, 5.1, or 7.8 × 10 -5 mol·L -1 ) and Darcy velocities typical for biofiltration ( U ¯ = 0.2-1.2 × 10 -4 m·s -1 ). In DC-free controls, we observed higher specific degradation rates ( q c ) at higher NAH concentrations. The q c depended on U ¯ , suggesting bioavailability restrictions depending on the hydraulic residence times. DC fields consistently increased q c and resulted in linearly increasing benefits up to 55% with rising hydraulic loadings relative to controls. We explain these biodegradation benefits by EOF-altered microscale flow profiles allowing for better NAH provision to bacteria attached to the collectors even though the EOF was calculated to be 100-800 times smaller than bulk water flow. Our data suggest that electrokinetic approaches may give rise to future technical applications that allow regulating biodegradation, for example, in response to fluctuating hydraulic loadings.

Background. Stimulation of osteogenesis in the treatment of certain orthopedic and trauma pathologies is a necessary element to ensure the best clinical outcome. The purpose of the present analytical review is to analyze the literature data in respect of evaluating the approaches and possibilities to stimulate osteogenesis using direct current. Methods. The search for literature data was performed in the open electronic databases of scientific literature PubMed and eLIBRARY under the following keywords and their combinations: “osteogenesis”, “reparative osteogenesis”, “direct electric current”, “orthopaedics”, “traumatology”, “electric current” (in Russian as well as in English language ). Results. According to some fundamental research, the stimulating effect of direct current lies is both in stimulating differentiation and proliferation of osteoblasts, and in stimulating differentiation of stem cells, mainly mesenchymal stem cells of bone marrow and adipose tissue, in the process of osteogenesis. The following stimulating technologies were developed and clinically tested to date: 1 — direct exposure of bone to the direct current; 2 — capacitive coupled stimulation; and 3 — inductive coupled (electromagnetic) stimulation. Analysis of clinical practice demonstrated that the first technology is most effective in terms of osteoreparation, but less safe than technology 2 and 3. It should be noted that there are no clear indications and modes of application for the abovementioned methods. Based on the data collected in the present analysis, technology 1 is considered by authors as the most promising. Safety of technology 1 can be enhanced by application of metal implants as electrodes in case those are planned to be used for medical reasons: wires, rods, staples, fixators, etc. Conclusion. Use of electric current to stimulate bone formation is a promising method which requires clarification in respect of indications and application modes.

Restrictions imposed on the characteristics of a semiconductor by the condition that ohmic losses in it are zero are established using equations of the thermodynamics of irreversible processes. A consequence of the negative value of the static permittivity of a semiconductor consisting of nanogranules or microgranules is that the intensity Е of the external electric field in its volume is zero. Because of the action of thermodynamic forces, the ohmic losses in the semiconductor are zero (jЕ = 0, where Е = 0) or nonzero depending on the direction of the constant electric current in a closed circuit. Theoretical explanation of the experimental data for the electrical conductivity of films consisting of Al2O3 and/ or NiO nanoparticles with chemisorbed hydrogen atoms is obtained. [ABSTRACT FROM AUTHOR]

Abstract Petroleum prediction in local objects and the applicability of geologic environment parameters in this regard are considered. The proposed guidelines for petroleum potential prediction are based on the analysis of the distribution of typomorphic epigenetic multivalent elements loosely fixed in rocks before and after electric current treatment. The advantage of geoelectrochemical methods providing data on the chemical composition of above-productive deposits is demonstrated. [ABSTRACT FROM AUTHOR]

We investigated the effect of sodium alginate hydrosols (1%) with 0.2% of NaCl treated with direct electric current (DC) used as a coating on microbial (Total Viable Counts, Psychrotrophic bacteria, yeast and molds, Lactic acid bacteria, Enterobacteriaceae), physiochemical (pH, lipid oxidation, antioxidant activity, weight loss, color) and sensory properties of skinned pork sausages or with artificial casing stored at 4 °C for 28 days. Moreover, the cytotoxicity analysis of sodium alginate hydrogels was performed. The results have shown that application of experimental coatings on the sausage surface resulted in reducing all tested groups of microorganisms compared to control after a 4-week storage. The cytotoxicity analysis revealed that proliferation of RAW 264.7 and L929 is not inhibited by the samples treated with 200 mA. Ferric reducing antioxidant power (FRAP) and free radical scavenging activity (DPPH) analyses showed that there are no significant differences in antioxidant properties between control samples and those covered with sodium alginate. After 28 days of storage, the highest value of thiobarbituric acid-reactive substances (TBARS) was noticed for variants treated with 400 mA (1.07 mg malondialdehyde/kg), while it was only slightly lower for the control sample (0.95 mg MDA/kg). The obtained results suggest that sodium alginate treated with DC may be used as a coating for food preservation because of its antimicrobial activity and lack of undesirable impact on the quality factors of sausages. [ABSTRACT FROM AUTHOR]

The effect of direct electric current on redistribution and microstructure of primary silicon in Al–Si melt during the solidification refining process was studied. Electric current generates a Joule heat, which slows down the cooling rate of the furnace. The precipitated area of primary silicon decreases from 100% to 36.67% with the increase of current density from 0 A/m 2 to 1.5×10 6 A/m 2 . Furthermore, direct current causes a convection leading to the migration of primary silicon in the opposite direction of electric field, which forms the accumulation area. The morphologies of primary silicon and the redistribution of B impurity were investigated under the effect of electric current. [ABSTRACT FROM AUTHOR]

Production of indigenous African leafy vegetables such as African nightshade (Solanum scabrum Mill.), whose high nutritional and medicinal value is well documented is still limited due to insufficient preharvest techniques. Electric current is known to improve quality in food crops. Therefore, in the present study, the effects of direct-electric-current (DC) on growth and characteristic bioactive and health promoting compounds were evaluated in different morphological sections, i.e., leaves and stems of African nightshade cv. Olevolosi. Six weeks old plants were exposed to different DC applied with a voltage of 8 and 16 V, 10 h/day for 12 days. Non-treated plants served as control. Plant growth, primary and secondary plant compounds were evaluated. Applying DC increased leaf fresh (11.5-14.4%) and dry (12.1-24.2%) weight as well as marketable leaves (29.1-55.3%). Biosynthesis of chlorophylls and carotenoids was enhanced by increased DC. Furthermore, dietary fibre fractions such as hemicellulose was promoted (23.3-45.3%) by DC applications, while cellulose and lignin remained unaffected. Minerals accumulated with increasing DC. Alteration of cell membrane permeability due to DC may enhance physiological processes leading to the improved growth and acceleration of bioactive compounds in African nightshade leaves.

The aim of the study was to investigate the effect of using direct electric current (DC) of 0, 200, and 400 mA for five minutes on the physiochemical properties, cytotoxicity, antibacterial, and antioxidant activity of sodium alginate hydrosols with different sodium chloride concentrations. The pH, oxidation-reduction potential (ORP), electrical conductivity (EC), and available chlorine concentration (ACC) were measured. The effect of sodium alginate hydrosols treated with DC on Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Escherichia coli, Salmonella enteritidis, Yersinia enterocolitica, Pseudomonas fluorescence, and RAW264.7 and L929 cells was investigated. Subsequently, the antioxidant properties of hydrosols were evaluated by determining the scavenging ability of 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and ferric reducing antioxidant power (FRAP). The results have shown that after applying 400 mA in hydrosol samples with 0.1% and 0.2% NaCl all tested bacteria were inactivated. The ACC concentration of C400 samples with NaCl was equal to 13.95 and 19.71 mg/L, respectively. The cytotoxicity analysis revealed that optimized electric field conditions and the addition of sodium chloride allow for the avoidance of toxicity effects on normal cells without disturbing the antibacterial effects. Due to the presence of oxidizing substances, the DPPH of variants treated with DC was lower than the DPPH of control samples. [ABSTRACT FROM AUTHOR]

A novel surface energy-based model is developed to examine more precisely vibrations of current-carrying double-nanowire-systems immersed in a longitudinal magnetic field. Using Biot-Savart and Lorentz laws, a more refined version of interwire interactional magnetic forces is presented. By employing Rayleigh beam theory, the equations of motion are derived. In fact, these are coupled integro-differential equations which are more accurate with respect to those of the previously developed models. For simply supported and clamped nanosystems, governing equations are analyzed via assumed mode method. The effects of interwire distance, slenderness ratio, electric current, magnetic field strength, and surface effect on the fundamental frequency are addressed carefully. The obtained results display the importance of exploiting the refined model for vibration analysis of nanosystems with low interwire distance, high electric current, and high magnetic field strength. [ABSTRACT FROM AUTHOR]

Electrochemical therapy (EChT) entails treatment of solid tumors with direct electric current (DC). This work evaluated the specific effects of anodic flow generated by DC on biochemical and metabolic features of the A549 human lung cancer cell line. Apoptosis was evaluated on the basis of caspase-3 activity and mitochondrial transmembrane potential dissipation. Cell morphology was analyzed using transmission electron microscopy, and lipid droplets were studied through morphometric analysis and X-ray qualitative elemental microanalysis. High-resolution respirometry was used to assess mitochondrial respiratory parameters. Results indicated A549 viability decreased in a dose-dependent manner with a prominent drop between 18 and 24 h after treatment ( p < 0.001), together with a two-fold increase in caspase-3 activity. AF-treatment induced a significantly increase ( p < 0.01) in the cell number with disrupted mitochondrial transmembrane potential . Furthermore, treated cells demonstrated important ultrastructural mitochondria damage and a three-fold increase in the cytoplasmic lipid bodies' number, quantified by morphometrical analyses. Conversely, 24 h after treatment, the cells presented a two-fold increase of residual oxygen consumption, accounting for 45.3% of basal oxygen consumption. These results show remarkable alterations promoted by anodic flow on human lung cancer cells which are possibly involved with the antitumoral effects of EChT. [ABSTRACT FROM AUTHOR]

Free vibration of current-carrying nano-scaled beams immersed in a magnetic field is of huge interest. To bridge this scientific gap, Rayleigh, Timoshenko, and higher-order beam models accounting for the surface energy are employed and their equations of motion are established appropriately. For spatial discretization of the deformations fields, a meshless approach is exploited. The effects of surface and shear deformation, electric current, magnetic field strength, and geometric parameters of the nanobeam on the first ten natural frequencies are examined and discussed. The critical values of slenderness ratio, nanobeam's diameter, electric current, and magnetic field strength, which are corresponding to the dynamically unstable nanobeams, are graphically identified. The obtained results indicate that the discrepancies between the frequencies by considering the surface effect and those evaluated without consideration of the surface energy would increase notably at the above-mentioned critical values. [ABSTRACT FROM AUTHOR]

Evolutions of properties and morphologies of secondary phases in 7050 alloy homogenized with direct electric current were studied in detail by conductivity measurement, tensile test and energy dispersive X-ray microanalysis. With increasing temperature, the conductivity decreases, and while the ultimate tensile strength, yield strength and elongation of 7050 alloy increase in alloy homogenized with direct electric current, and reaches the saturation values at 440 °C/2 h. During homogenization, the brighter white AlZnMgCu phase having (weight ratio %) 12.1–15.2Mg, 27.2–32.1Al, 20.9–26.2Cu and 31.4–34.4Zn gradually transforms to the gray phase having (weight ratio %) 10.3–15.1Mg, 41.4–53.7Al, 22.9–35.2Cu and 5.8–13.1Zn and then to the dark gray phase having (weight ratio %) 10.6–14.2 Mg, 38.2–54.9Al, 23.3–44Cu, and 3.6–9.2Zn. With the application of direct electric current, the elemental diffusion network becomes profuse, the amount of gray phase increases, the diffusion of Zn accelerates, the apparent activation of the transformation from AlZnMgCu to Al 2 MgCu decreases from 125.52 kJ/mol for the alloy homogenized without direct electric current to 118.82 kJ/mol, and the area fraction of secondary phase decreases by 38% at 450 °C. [ABSTRACT FROM AUTHOR]

The direct current-induced suppression of the Portevin - Le Chatelier (PLC) effect has been revealed and investigated in Al-5wt% Mg and Al-6wt% Mg alloys during tensile tests at a constant strain rate. Suppression of the PLC effect by direct electric current manifests itself as an increase in the critical strain εc for the onset of serration flow with increasing current density exceeding a certain critical value jc which depends on the weight content of Mg in Al-Mg alloy. The current density range in which the transition from a jerky tensile curve to a smooth one occurs is found to depend on the type of PLC instabilities apart from the testing temperature and an imposed strain rate. The obtained results show that the observed suppression of jerky flow by electric current is not directly associated with Joule heating per se of the whole sample. Possible mechanisms of the phenomenon are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Inactivation effect of an electric current treatment combining both 188 μA/m2 DC and 251 μA/m2 AC on Gram negative, Gram positive bacteria and their mixed culture, which were isolated from hides, was separately analyzed. This electric treatment, applied for 16 min was found to be fairly effective in reducing the bacterial cell count (7.10–7.48 log10 colony forming units/mL) to a relatively low level (4.52–4.90 log10 colony forming units/mL). At this level bacterial damage to the hides is reduced in soak liquors. Cheap and efficient electric current may be applied to rapidly reduce the destructive bacterial populations in main hide-soak liquors. [Copyright &y& Elsevier]

Abstract: Low-voltage direct current was applied to beef, inoculated with Escherichia coli O157:H7 on the surface covered with a thin film of 0.15M NaCl solution. Experiments were conducted with 15, 30, and 45mA/cm2 currents; 1, 10 and 100kHz frequencies; 30, 50 and 70% duty cycles, and 2, 8 and 16min treatment durations. Increase in current intensity, frequency, duty cycle, and treatment duration increased the % reduction of E. coli. A maximum reduction of 98.9% was achieved. Sensory color analysis showed significant differences between treated and untreated beef. The maximum temperature rise of NaCl solution was 31.9°C. [Copyright &y& Elsevier]

Abstract: Inactivation of bacteria by electric currents has received much attention due to its high efficiency, low cost, and ease of application. Therefore, the antibacterial effect of passing 2A direct electric current for 50min on mesophilic bacteria in both first and main hide-soak liquors obtained from different tanneries in Tuzla-İstanbul, Türkiye was examined. The mesophilic bacterial numbers in the main hide-soak liquors were higher than that of the first hide-soak liquors. The total numbers of gram-negative bacteria (101–104 CFU/mL) and halotolerant bacteria (103–104 CFU/mL), in both first and main hide-soak liquors, were almost the same. The numbers of total of proteolytic and lipolytic mesophilic bacteria and the total of proteolytic and lipolytic halotolerant bacteria in the main hide-soak liquors were higher than that of the first hide-soak liquors. Mesophilic bacteria in the first (seven samples) and main (three samples) hide-soak liquors were inactivated after 20–30min of electrical treatment. In the other four main hide-soak liquors, the inactivation occurred after 50min of treatment. The most important result of this experiment is that there was a correlation between the voltage level and the numbers of bacteria in the electrolysis cell. The bacterial populations in the hide-soak liquors decreased proportionally to the voltage level until all of the bacterial population was inactivated. After the bacteria in the hide-soak liquors were completely destroyed by direct electric current, the voltage level started to increase. This important clue might be used to predict the inactivation time of all of the bacterial population in hide-soak liquors in the hide industry. It is suggested that the bacterial inactivation in hide-soak liquors by electrical treatment might be used in tanneries, which do not have a waste treatment system and discharge their effluents directly into environment. [Copyright &y& Elsevier]

White croaker (Micropogonias furnieri) were submitted to a direct electric current post-mortem and stored refrigerated at 4°C for 16 days. Flesh and surface of electrically treated fish exhibited higher mesophilic bacteria counts than controls on the 3rd and on the 6th day of storage, respectively. Conversely, electrical treatment reduced flesh and surface psychrotrophic bacteria counts on the 12th and on the 16th day of storage, respectively. These changes had no influence on fish shelf life since they occurred when microbial counts were higher than the recommended limit for human consumption. Electrical treatment significantly reduced total count of mesophilic but did not affect psychrotrophic bacteria in the water used in fish treatment. These results suggest that although post-mortem application of electric current does not increase fish shelf life, it may reduce microbial counts in the water used in fish processing. [Copyright &y& Elsevier]

Treatment with direct electric current (DC) influences the growth of several cancer cells. In this work, we evaluated the effects of DC treatment on the human leukemic cell line HL60. Human cells were separately treated in the presence of the cathode or the anode or without contact with the electrodes. In all systems, DC-treated cells presented an impaired ability to proliferate. Growth inhibition was dependent on the generation of soluble products of electrolysis. Cathodic treatment of HL60 cells predominantly induced lysis, whereas treatment without contact with electrodes did not induce alterations in cell viability. In contrast, cell stimulation by the anode resulted in irreversible membrane damage, as demonstrated by trypan blue and 7-aminoactinomycin staining. Analysis of these cells by transmission electron microscopy indicated that necrosis is a major mechanism inducing cell death. In addition, apoptotic-like cells were observed under light microscopy after anodic treatment. Accordingly, DNA from anodic-treated cells presented a typical pattern of apoptosis. Apoptotic cell death was only generated after the treatment of HL60 cells in conditions in which the generation of chloride-derived compounds was favored. These results indicate that the nature of the products from cathodic or anodic reactions differently influences the mechanisms of cell death induced by DC-derived toxic compounds. [ABSTRACT FROM AUTHOR]

A steady-state model was developed to predict the biofilm thickness, microbial distribution and substrate fluxes based on the microbial interactions in multispecies biofilms under the action of an electric field. The experimental evaluations were carried out in completely mixed biofilm reactors where nitrifying bacteria compete with glucose-utilizing heterotrophs. The experimental results showed that the model successfully describe the competition of the two types of bacteria. The biofilm thickness and flux of NH4+ increases with increasing electric field strength, whilst the flux of glucose slightly decreases. In addition, increasing the current density not only forces autotrophs and heterotrophs to move into the deeper biofilm but also decreases the biofilm thickness and substrate fluxes. [Copyright &y& Elsevier]

The nitrifying bacteria in activated sludge and biofilms consisting of the bacteria immobilized on polypropylene packing were subjected to an electric current via two electrodes. In activated sludge, the metabolism of nitrifying bacteria was inhibited when the applied current was over 2.5 A m-2, whilst in biofilms, inhibition began when the current reached 5 A m-2. At 15 A m-2, the nitrification rate of NH4+-N in a biofilm with a bacterial density of 1.62 g total solids, dry wt m-2 decreased to about 80% of its initial value. Ninety-two % of the initial biomass on the packing was retained after 36 h. [ABSTRACT FROM AUTHOR]

Electrochemical treatment is an alternative modality for tumor treatment based on the application of a low intensity direct electric current to the tumor tissue through two or more platinum electrodes placed within the tumor zone or in the surrounding areas. This treatment is noted for its great effectiveness, minimal invasiveness and local effect. Several studies have been conducted worldwide to evaluate the antitumoral effect of this therapy. In all these studies a variety of biochemical and physiological responses of tumors to the applied treatment have been obtained. By this reason, researchers have suggested various mechanisms to explain how direct electric current destroys tumor cells. Although, it is generally accepted this treatment induces electrolysis, electroosmosis and electroporation in tumoral tissues. However, action mechanism of this alternative modality on the tumor tissue is not well understood. Although the principle of Electrochemical treatment is simple, a standardized method is not yet available. The mechanism by which Electrochemical treatment affects tumor growth and survival may represent more complex process. The present work analyzes the latest and most important research done on the electrochemical treatment of tumors. We conclude with our point of view about the destruction mechanism features of this alternative therapy. Also, we suggest some mechanisms and strategies from the thermodynamic point of view for this therapy. In the area of Electrochemical treatment of cancer this tool has been exploited very little and much work remains to be done. Electrochemical treatment constitutes a good therapeutic option for patients that have failed the conventional oncology methods.

The literature shows that the effects of direct electric currents on biological material are numerous, including bactericidal, fungicidal, parasiticidal, and anti-tumoral, among others. Non-pathogenic trypanosomatids, such as Herpetomonas samuelpessoai, have emerged as important models for the study of basic biological processes performed by a eukaryotic cell. The present study reports a dose-dependent anti-protozoan effect of direct electric treatment with both cathodic and anodic current flows on H. samuelpessoai cells. The damaging effects can be attributable to the electrolysis products generated during electric stimulation. The pH of the cell suspension was progressively augmented from 7.4 to 10.5 after the cathodic treatment. In contrast, the anodic treatment caused a pH decrease varying from 7.4 to 6.5. Transmission electron microscopy analyses revealed profound alterations in vital cellular structures (e.g., mitochondrion, kinetoplast, flagellum, flagellar pocket, nucleus, and plasma membrane) after exposure to both cathodic and anodic current flows. Specifically, cathodic current flow treatment induced the appearance of autophagic-like structures on parasite cells, while those submitted to an anodic current flow presented marked disorganization of plasma membrane and necrotic appearance. However, parasites treated in the intermediary chamber (without contact with the electrodes) did not present significant changes in viability or morphology, and no pH variation was detected in this system. The use of H. samuelpessoai as a biological model and the direct electric current experimental approach used in our study provide important information for understanding the mechanisms involved in the cytotoxic effects of this physical agent., (Copyright © 2011 Wiley Periodicals, Inc.)

Inhibition of tumor growth induced by treatment with direct electric current (DC) has been reported in several models. One of the mechanisms responsible for the antitumoral activity of DC is the generation of oxidative species, known as chloramines. With the aim of increasing chloramine production in the electrolytic medium and optimizing the antitumoral effects of DC, poly(ɛ-caprolactone) (PCL) nanoparticles (NPs) loaded with the amino acid tyrosine were obtained. The physical-chemical characterization showed that the NPs presented size in nanometric range and monomodal distribution. A slightly negative electrokinetic potential was also found in both blank NPs and L-tyrosine-loaded PCL NPs. The yield of the loading process was approximately 50%. Within 3 h of dissolution assay, a burst release of about 80% L-tyrosine was obtained. The in vitro cytotoxicity of DC was significantly increased when associated with L-tyrosine-loaded NPs, using a murine multidrug-resistant melanoma cell line model. This study showed that the use of the combination of nanotechnology and DC has a promising antineoplastic potential and opens a new perspective in cancer therapy.

Snake venoms are complex toxin mixtures. Viperidae and Crotalidae venoms, which are hemotoxic, are responsible for most of the envenomations around the world. Administration of antivenins aimed at the neutralization of toxins in humans is prone to potential risks. Neutralization of snake venom toxins has been achieved through different approaches: plant extracts have been utilized in etnomedicine. Direct electric current from low voltage showed neutralizing properties against venom phospholipase A2 and metalloproteases. This mini-review summarizes new achievements in venom key component inhibition. A deeper knowledge of alternative ways to inhibit venom toxins may provide supplemental treatments to serum therapy.