Publications by authors named "G Allen Bridges"

This paper presents a lens-free imaging approach utilizing an array of light sources, capable of measuring the dielectric properties of many particles simultaneously. This method employs coplanar electrodes to induce velocity changes in flowing particles through dielectrophoretic forces, allowing the inference of individual particle properties from differential velocity changes. Both positive and negative forces are detectable.

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In this paper, we present a microfluidic flow cytometer for simultaneous imaging and dielectric characterization of individual biological cells within a flow. Utilizing a combination of dielectrophoresis (DEP) and high-speed imaging, this system offers a dual-modality approach to analyze both cell morphology and dielectric properties, enhancing the ability to analyze, characterize, and discriminate cells in a heterogeneous population. A high-speed camera is used to capture images of and track multiple cells in real-time as they flow through a microfluidic channel.

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Bulk electrical impedance spectroscopy (bio-capacitance) probes, hold significant promise for real-time cell monitoring in bioprocesses. Focusing on Chinese hamster ovary (CHO) cells, we present a sensitivity analysis framework to assess the impact of cell and culture properties on the complex permittivity spectrum, ε, and its associated parameters, permittivity increment, Δε, critical frequency, f, and Cole-Cole parameter, α, measured by bio-capacitance probes. Our sensitivity analysis showed that Δε is highly sensitive to cell size and concentration, making it suitable for estimating biovolume during the exponential growth phase, whereas f provides information about cumulative changes in cell size, membrane permittivity, and cytoplasm conductivity during the transition to death phase.

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This paper presents a wireless chipless resonator-based sensor for measuring the absolute value of an external time-varying electric field. The sensor is developed using contactless air-filled substrate-integrated waveguide (CLAF-SIW) technology. The sensor employs a low-impedance electromagnetic band gap structure to confine the electric field within the sensor's air cavity.

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Resident-as-teacher initiatives are traditionally specialty-specific and performed in-person, limiting ability to disseminate essential teaching skills to all residents. The aim of this study was to develop, implement, and evaluate a resident-as-teacher interactive e-learning module on growth mindset and coaching. The module was designed and implemented between August 2022 and March 2023.

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