Joseph West

Bio: Joseph West is an academic researcher from Ohio State University. The author has contributed to research in topics: Electromagnetic coil & Eddy current. The author has an hindex of 4, co-authored 16 publications receiving 93 citations.

Ex vivo electrical impedance measurements on excised hepatic tissue from human patients with metastatic colorectal cancer.

Abstract: Point-wise ex vivo electrical impedance spectroscopy measurements were conducted on excised hepatic tissue from human patients with metastatic colorectal cancer using a linear four-electrode impedance probe. This study of 132 measurements from 10 colorectal cancer patients, the largest to date, reports that the equivalent electrical conductivity for tumor tissue is significantly higher than normal tissue (p < 0.01), ranging from 2–5 times greater over the measured frequency range of 100 Hz–1 MHz. Difference in tissue electrical permittivity is also found to be statistically significant across most frequencies. Furthermore, the complex impedance is also reported for both normal and tumor tissue. Consistent with trends for tissue electrical conductivity, normal tissue has a significantly higher impedance than tumor tissue (p < 0.01), as well as a higher net capacitive phase shift (33° for normal liver tissue in contrast to 10° for tumor tissue).

Electrophoretic drawing of continuous fibers of single-walled carbon nanotubes

Abstract: Control over the current during electrophoretic drawing of continuous fibers of single-walled carbon nanotubes (SWCNTs) is shown to be critical in producing long fibers with specific diameters. In the process, as-produced SWCNTs are first dispersed in N,N-dimethylformamide (DMF) by sonication. A tungsten probe tip is then immersed in the SWCNT∕DMF solution, and a dc bias is applied between the tip and another electrode at the bottom of the beaker containing the solution. After a dark cloud several millimeters in diameter develops around the tip, the electrode is withdrawn to form continuous macroscopic fibers of SWCNTs. The resulting fiber length and diameter are found to be principally determined by the magnitude of the current. Under constant voltage conditions where the current is allowed to vary, the fibers are short (several millimeters long) and their diameters vary drastically along their lengths. Of significance is the fact that when the current is maintained at constant values, fibers several cen...

Non-contact method for directing electrotaxis

Abstract: We present a method to induce electric fields and drive electrotaxis (galvanotaxis) without the need for electrodes to be in contact with the media containing the cell cultures. We report experimental results using a modification of the transmembrane assay, demonstrating the hindrance of migration of breast cancer cells (SCP2) when an induced a.c. electric field is present in the appropriate direction (i.e. in the direction of migration). Of significance is that migration of these cells is hindered at electric field strengths many orders of magnitude (5 to 6) below those previously reported for d.c. electrotaxis and even in the presence of a chemokine (SDF-1α) or a growth factor (EGF). Induced a.c. electric fields applied in the direction of migration are also shown to hinder motility of non-transformed human mammary epithelial cells (MCF10A) in the presence of the growth factor EGF. In addition, we also show how our method can be applied to other cell migration assays (scratch assay) and by changing the coil design and holder, that it is also compatible with commercially available multi-well culture plates.

Electromagnetic system and method

Abstract: Differences of electromagnetic (EM) properties between healthy and cancerous tissues allow detection of abnormal conditions occurring in a tissue of an animal, for example, intra-operative cancer detection. By using a time-varying EM field, electrical eddy currents are generated in the tissue sample, and assessed using phase-sensitive detection. In some aspects, a change in phase shift between the voltage in a receiver coil and the voltage in a driver coil provide a direct and immediate indication of differences in EM properties of specimens.

Printed Electroceutical Dressings for the Inhibition of Biofilms and Treatment of Chronic Wounds

Abstract: We report on an innovative, fabric-based conformable, and easily fabricated electroceutical wound dressing that inhibits bacterial biofilm infections and shows significant promise for healing chronic wounds. Cyclic voltammetry demonstrates the ability of the electroceutical to produce reactive oxygen species, primarily HOCl that is responsible for bacterial inhibition. In vitro investigation with the lawn biofilm grown on a soft tissue mimic assay shows the efficacy of the dressing against both Gram-positive and Gram-negative bacteria in the biofilm form. In vivo, the printed electroceutical dressing was utilized as an intervention treatment for a canine subject with a non-healing wound due to a year-long persistent polymicrobial infection. The clinical case study with the canine subject exhibited the applicability in a clinical setting with the results showing infection inhibition within 11 days of initial treatment. This printed electroceutical dressing was integrated with a Bluetooth® enabled circuit allowing remote monitoring of the current flow within the wound bed. The potential to monitor wounds remotely in real-time with a Bluetooth® enabled circuit proposes a new physical biomarker for management of infected, chronic wounds. [2020-0129]

Iodine doped carbon nanotube cables exceeding specific electrical conductivity of metals

Abstract: Creating highly electrically conducting cables from macroscopic aggregates of carbon nanotubes, to replace metallic wires, is still a dream. Here we report the fabrication of iodine-doped, double-walled nanotube cables having electrical resistivity reaching ∼10−7 Ω.m. Due to the low density, their specific conductivity (conductivity/weight) is higher than copper and aluminum and is only just below that of the highest specific conductivity metal, sodium. The cables exhibit high current-carrying capacity of 104∼105 A/cm2 and can be joined together into arbitrary length and diameter, without degradation of their electrical properties. The application of such nanotube cables is demonstrated by partly replacing metal wires in a household light bulb circuit. The conductivity variation as a function of temperature for the cables is five times smaller than that for copper. The high conductivity nanotube cables could find a range of applications, from low dimensional interconnects to transmission lines.

Mechanisms of invasion and motility of high-grade gliomas in the brain.

Abstract: High-grade gliomas are especially difficult tumors to treat due to their invasive behavior. This has led to extensive research focusing on arresting glioma cell migration. Cell migration involves the sensing of a migratory cue, followed by polarization in the direction of the cue, and reorganization of the actin cytoskeleton to allow for a protrusive leading edge and a contractile trailing edge. Transmission of these forces to produce motility also requires adhesive interactions of the cell with the extracellular microenvironment. In glioma cells, transmembrane receptors such as CD44 and integrins bind the cell to the surrounding extracellular matrix that provides a substrate on which the cell can exert the requisite forces for cell motility. These various essential parts of the migratory machinery are potential targets to halt glioma cell invasion. In this review, we discuss the mechanisms of glioma cell migration and how they may be targeted in anti-invasion therapies.

Electrokinetic assembly of selenium and silver nanowires into macroscopic fibers.

Abstract: Solution-phase synthesized nanowires with high aspect ratios can be a challenge to assemble into desired structures. As synthesized, these nanostructures readily bend and entangle with each other t...