Analysis of the Differential Gene and Protein Expression Profiles of Corneal Epithelial Cells Stimulated with Alternating Current Electric Fields

In cells, intrinsic endogenous direct current (DC) electric fields (EFs) serve as morphogenetic cues and are necessary for several important cellular responses including activation of multiple signaling pathways, cell migration, tissue regeneration and wound healing. Endogenous DC EFs, generated spontaneously following injury in physiological conditions, directly correlate with wound healing rate, and different cell types respond to these EFs via directional orientation and migration. Application of external DC EFs results in electrode polarity and is known to activate intracellular signaling events in specific direction. In contrast, alternating current (AC) EFs are known to induce continuous bidirectional flow of charged particles without electrode polarity and also minimize electrode corrosion. In this context, the present study is designed to study effects of AC EFs on corneal epithelial cell gene and protein expression profiles in vitro. We performed gene and antibody arrays, analyzed the data to study specific influence of AC EFs, and report that AC EFs has no deleterious effect on epithelial cell function. Gene Ontology results, following gene and protein array data analysis, showed that AC EFs influence similar biological processes that are predominantly responsive to organic substance, chemical, or external stimuli. Both arrays activate cytokine–cytokine receptor interaction, MAPK and IL-17 signaling pathways. Further, in comparison to the gene array data, the protein array data show enrichment of diverse activated signaling pathways through several interconnecting networks.

Performance Study of Biocompatible Recast Layer Formation on Ti6Al4V by using Electrical Discharge Coatings

Long-term implantation of titanium-based alloy, Ti6Al4V can be harmful in human bodies due to the release of aluminium and vanadium elements. Thus, a biocompatible barrier coating can be applied towards corrosion and wear resistance of the implant. In this research, the surface of a biomedical grade of Ti6Al4V was coated with a thin film of biomaterial ceramic by the electrical discharge coatings (EDC) using a pure graphite electrode. Polarity, discharge duration and pulse interval were varied to investigate the formation of recast layer thickness (RLT) on the surface of titanium alloys. RLT was measured from cross-sectioned samples using a high magnification optical microscopy. From the statistical analyses of variance, the response was significantly influenced by the pulse interval, followed with electrode polarity. Additionally, the interaction of polarity to discharge duration and pulse interval also significantly affect the RLT. In order to obtain a more uniform recast layer formation, the process condition should be in reverse polarity with a low setting of pulse interval

Electrical Properties of Reversed-Polarity Ball Plasmoid Discharges

Ball plasmoid discharges are a unique type of atmospheric-pressure plasma discharge with a lifetime on the order of a hundred milliseconds without attachment to a power source. These discharges are generated by a moderate current pulse over the surface of an aqueous electrolyte, and some consider the spherical plasmoid that results to bear some resemblance to ball lightning. This article presents the first analysis of the electrical properties of ball plasmoid discharges in a reversed-polarity configuration, i.e., with the central electrode serving as the anode rather than as the cathode. These experiments demonstrate that ball plasmoids can indeed be generated with either electrode polarity with similar observable properties. These results are contrary to what has previously been discussed in the literature and raise additional questions regarding formation mechanisms of ball plasmoids. Analysis of images and electrical measurements collected at various discharge energies show that two distinct processes occur during discharges with our circuitry and in this reversed-polarity configuration: the formation of spark channels between the anode and electrolyte, and the generation of streamers and a jet from the surface of the anode.

Research on Shape Changes in Cylinder Electrodes Incident to Micro-EDM

This paper discusses electrode wear changes under different operating conditions. A series of experiments were designed and conducted using an EDM machine tool with a rectangular pulse power supply. The phenomena of the cylinder electrode shape changes were abstracted from the experiments; the change mechanisms of the end face are discussed and verified by experimental data and interrelated theory. The results disclose that the shape of an electrode is subject to pulse-on time, discharge current density, and electrode polarity.