Neural electrodes are an important part of brain-machine interface devices that can restore functionality to patients with sensory and movement impairments including spinal cord injury and limb loss. Currently, chronically implanted neural electrodes induce an unfavorable tissue response which includes inflammation, scar formation, and neuronal cell death, eventually causing loss of electrode functionality in the long term. The objective of this research was to develop a coating to improve the tissue response to implanted neural electrodes. The hypothesis was that coating the surface of neural electrodes with a non-fouling, anti-inflammatory coating would cause reduced inflammation and a better tissue response to the implanted electrode. We developed a polymer coating with non-fouling characteristics, incorporated an anti-inflammatory agent, and engineered a stimulus-responsive degradable portion for on-demand release of the anti-inflammatory agent in response to inflammatory stimuli. We characterized the coating using XPS and ellipsometry, and analyzed cell adhesion, cell spreading, and cytokine release in vitro. We analyzed the in vivo tissue response using immunohistochemistry and microarray qRT-PCR. Although no differences were observed among the samples for inflammatory cell markers, lower IgG penetration into the tissue around PEG + IL-1Ra coated electrodes suggests an improvement in BBB integrity. Gene expression analysis showed higher expression of IL-6 and MMP-2 around PEG + IL-1Ra samples, as well as an increase in CNTF expression, an important marker for neuronal survival. An important finding from this research is the increased neuronal survival around coated electrodes compared to uncoated controls, which is a significant finding as neuronal survival near the implant interface is an essential part of maintaining electrode functionality.

The purpose of this paper is to understand why a host country (HC) shows ex post opportunistic behaviors in E&P projects and frequently forces international oil companies (IOCs) to renegotiate previously signed contracts. This research employs the concept of asset specificity and hold-up problem in transaction cost economics (TCE). It then examines the unique characteristics of E&P projects, HC’s opportunistic behaviors, and IOCs’ safeguards. For a case study analyzing the implications between the economic theory and HC’s ex post opportunism in oil E&P project, I have selected Kazakhstan. The result is that HC’s ex post opportunism can be explained by a hold-up problem resulting from IOCs’ sunk investments and the unique characteristics of the oil E&P industry. When IOCs’ important capital assets become sunk investments and the price of oil increases rapidly, HC has a strong incentive to appropriate IOCs’ profits through ex post opportunism. Yet at the same time, HC must consider the damage to its reputation when deciding the extent and ways of its ex post opportunistic behaviors in oil E&P projects. / text

published_or_final_version / Medicine / Master / Master of Philosophy

published_or_final_version / Medicine / Master / Master of Philosophy

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