In the US alone, more than 500,000 coronary artery bypass procedures are performed annually. Tissue engineering shows the potential to construct functional grafts to overcome the limited availability of autologous saphenous veins, relatively poor elasticity and low compliance of synthetic materials (mainly Dacron and polytetrafluoroethylene). In order to meet the low modulus associate with myocyte differentiation, the high suture retention and an ultimate tensile strength (UTS) sufficient to withstand implantation and peak physiological stresses, we designed and characterized a multi-component scaffold comprised of polyurethane electrospun mesh layers bonded together by a fibrin hydrogel matrix. We have demonstrated this composite construct retains the high tensile strength and suture retention strength but displays a "J-shaped" mechanical response similar to that of native coronary artery. To improve our design, poly(ethylene glycol) diacrylate based hydrogel system was utilized as a blank slate to study the phenotypic regulation by cell material interactions. Fibrinogen, fibronectin, laminin and collagen type IV were incorporated into the hydrogel to mimic the stimuli from extracellular matrix (ECM) proteins. Surprisingly, no significant effect was detected on induction of smooth muscle cell (SMC) differentiation marker expression, activation of mitogen-activated protein (MAP) kinases pathway, or alteration of surface integrin expression profile. However, fibronectin showed repression of undesired phenotypes in SMC differentiation. In contrast to ECM proteins, glycosaminoglycans (GAGs) showed more influence on regulating SMC phenotype. By using a scaffold environment intended to be mimetic of early atherosclerosis, the impact of GAG identity on SMC foam cell formation was explored. We focused on chondroitin sulfate C (CSC), dermatan sulfate (DS), and an intermediate molecular weight hyaluronan (HA_IMW, ~400 kDa), the levels and/or distribution of which are significantly altered in atherosclerosis. CSC and DS hydrogels were associated with greater SMC phagocytosis of apolipoprotein B than HA_IMW gels. However, only SMCs in DS constructs maintained increased expression of adipocyte marker A-FABP relative to HA_IMW gels over 35 days of culture. Combined, our results suggested interesting roles for fibronectin and HA_IMW in repression of undesired phenotypes in SMC differentiation, which could give insights into rational design of novel biomaterials for vascular tissue engineering applications.

Thesis (M.S.) in Forest Resources--University of Maine, 2009. / Includes vita. Includes bibliographical references (leaves 143-148).

No description available.

Theoretical and experimental results show that the performance of a load-bearing surface in hydrodynamic lubrication may be enhanced by engineering a definable surface texture onto the surface. These surface textures are in the form of protrusions (positive asperities) or cavities (negative asperities) of known size and geometry. The benefits of such surface textures include lower friction torque, higher load capacity and lower operating temperatures. This Thesis details a fabrication process to manufacture such surface textures/asperities on flat surfaces. The asperities are fabricated using a UV photolithography process followed by electroplating. A complete surface characterization is done to evaluate the effectiveness of the manufacturing process. From the characterization results, some errors in asperity geometry are identified and statistically quantified. These errors are found to be normally distributed and the random surface roughness is 1 to 3 orders of magnitude less than the deterministic feature size. The accuracy of the manufacturing process for fabricating the asperities was found to lie within 6.5 % of the desired value over all the errors studied. Finally, a sensitivity analysis is done to theoretically evaluate the effect of some of these errors in the hydrodynamic lubrication regime.

No description available.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 72-74). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [208]-237).

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 112-123). Also available on the World Wide Web.

The goal of Synthetic Biology is to engineer systems from biological parts. One class of systems are those whose purpose is to process information. My work seeks to build transcription-based devices for use in combinational digital logic. Preliminary characterization experiments show that existing devices fall short of desired device behavior. I propose to develop a novel implementation of transcription-based logic by designing synthetic transcription factors from well-characterized DNA binding and dimerization domains. Initial modeling work serves to inform design of these devices. / Poster presented at the 2005 ICSB meeting, held at Harvard Medical School in Boston, MA.

The goal of Synthetic Biology is to engineer systems from biological parts. One class of systems are those whose purpose is to process information. My work seeks to build transcription-based devices for use in combinational digital logic. Preliminary characterization experiments show that existing devices fall short of desired device behavior. I propose to develop a novel implementation of transcription-based logic by designing synthetic transcription factors from well-characterized DNA binding and dimerization domains. Initial modeling work serves to inform design of these devices. / Poster presented at the 2005 ICSB meeting, held at Harvard Medical School in Boston, MA.