By physically modelling the scattering of a broadband Gaussian beam projected from an azimuthally scanned catheter, we formulate an inverse scattering solution for optical coherence tomography for intravascular or gas...
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A polymer gel is a cross-linked polymer which undergoes a reversible volume and/or sol-gel phase transition in response to physiological (temperature, pH and presence of ion in organism fluids) or other external (elec...
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A polymer gel is a cross-linked polymer which undergoes a reversible volume and/or sol-gel phase transition in response to physiological (temperature, pH and presence of ion in organism fluids) or other external (electric field, light) stimuli. In structurally soft gels, the motion of polymer network and the diffusion of ions easily take place by an external stimulus. A typical function of gel containing ionic groups is to swell under the influence of an electric field, making it useful for wide biomedical applications. In this study, poly(acrylic acid) (PAA) hydrogel network was prepared by free radical polymerization whose average molecular weight between crosslinkes was calculated as 18500 g/mol and its homogeneity assessment evaluated by comparing 30 samples swelling ratios after 48 h soaking in distilled deionized water. The swelling behaviour of PAA under an electric field application was also investigated as a function of cross-linking agent and electric field intensity variation. It is seen that equilibrium swelling ratio of PAA gel increases from 16 (no electric field) to 30 (by application of 300 V/m electric field), however this variation is dependent on the sample location relative to electrodes. The normalized swelling ratio of sample changes by 4.8 to 0.9 relative to its distance from positive electrode. Increasing the concentration of cross-linking agent (EGDMA) from 0.14 to 0.71 molar percent of monomer resulted in 45% decrease of gel volume fraction. It is proven that applying an external electric field can make an improvement in the time-response of the hydrogel expansion phase and swelling behaviour.
We present the use of the polysaccharide chitosan for immobilizing biomolecules on microfabricated device surfaces. The main advantages of chitosan are its abundance of primary amine groups and its ability to be elect...
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Breast optical property studies have been conducted, yielding data for macroscopic and microscopic optical imaging. Absent, however, are investigations of breast tissue refractive indices. We present measurements of r...
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Humans have exceptional abilities to learn new skills, manipulate tools and objects, and interact with our environment. In order to be successful at these tasks, our brain has become exceptionally well adapted to lear...
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Tomographic coherent imaging of mammary lesions has been demonstrated as an effective means by which to identify boundaries between healthy and diseased tissue. While these results are encouraging, recent efforts towa...
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An acousto-optical microfluidic flow cytometer featuring femtoliter fluid-displacement was demonstrated with cellular sorting efficiencies at upwards of 99% at 5kHz frequency actuation. Simulation and validation was p...
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Neural prostheses have received considerable attention due to their potential to dramatically improve the quality of life of severely disabled patients. Cortically-controlled prostheses are able to translate neural ac...
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Neural prostheses have received considerable attention due to their potential to dramatically improve the quality of life of severely disabled patients. Cortically-controlled prostheses are able to translate neural activity from cerebral cortex into control signals for guiding computer cursors or prosthetic limbs. Non-invasive and invasive electrode techniques can be used to measure neural activity, with the latter promising considerably higher levels of performance and therefore functionality to patients. We review here some of our recent experimental and computational work aimed at establishing a principled design methodology to increase electrodebased cortical prosthesis performance to near theoretical limits. Studies discussed include translating unprecedentedly brief periods of “plan” activity into high information rate (6.5 bits/s) control signals, improving decode algorithms and optimizing visual target locations for further performance increases, and recording from chronically implanted arrays in freely behaving monkeys to characterize neuron stability. Taken together, these results should substantially increase the clinical viability of cortical prostheses.
The Wireless Integrated MicroSystems (WIMS) engineering Research Center (ERC) has developed a broad comprehensive MEMS and microsystem curriculum suitable for upper-level undergraduate students, graduate students, and...
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