This work explores the possibilities of robust, noise adaptive and automatic segmentation of driver eye movements into comparable quantities as defined in the ISO 15007 and SAE J2396 standards for in-vehicle visual demand measurements. Driver eye movements have many potential applications, from the detection of driver distraction, drowsiness and mental workload, to the optimization of in-vehicle HMIs. This work focuses on SeeingMachines head and eye-tracking system SleepyHead (or FaceLAB), but is applicable to data from other similar eye-tracking systems. A robust and noise adaptive hybrid algorithm, based on two different change detection protocols and facts about eye-physiology, has been developed. The algorithm has been validated against data, video transcribed according to the ISO/SAE standards. This approach was highly successful, revealing correlations in the region of 0.999 between analysis types i.e. video transcription and the analysis developed in this work. Also, a real-time segmentation algorithm, with a unique initialization fefature, has been developed and validated based on the same approach. This work enables real-time in-vehicle systems, based on driver eye-movements, to be developed and tested in real driving conditions. Furthermore, it has augmented FaceLAB by providing a tool that can easily be used when analysis of eye movements are of interest e.g. HMI and ergonomics studies, analysis of warnings, driver workload estimation etc.

<p>Methylglyoxal (MG) is a reactive glucose metabolite and a known causative factor for hypertension and diabetes. Hydrogen sulfide (H₂S), on the other hand, is a gasotransmitter with multifaceted physiological functions, including anti-oxidant and vasodilatory properties. The present study demonstrates that MG and H₂S can interact with and modulate each other's functions. Upon <i>in vitro</i> incubations, we found that MG and H₂S can directly interact to form three possible MG-H₂S adducts. Furthermore, the endogenous production level of MG or H₂S was significantly reduced in a concentration-dependent manner in rat vascular smooth muscle cells (A-10 cells) treated with NaHS, a H₂S donor, or MG, respectively. Indeed, MG-treated A-10 cells exhibited a concentration-dependent down-regulation of the protein and activity level of cystathionine &gamma;-lyase (CSE), the main H₂S-generating enzyme in the vasculature. Moreover, H₂S can induce the inhibition of MG-generated ROS production in a concentration-dependent manner in A-10 cells. In 6-22 week-old CSE knockout male mice (CSE^-/-), mice with lower levels of vascular H₂S, we observed a significant elevation in MG levels in both plasma and renal extracts. Renal triosephosphates were also significantly increased in the 6-22 week-old CSE^-/- mice. To identify the source of the elevated renal MG levels, we found that the activity of fructose-1,6-bisphosphatase (FBPase), the rate-limiting enzyme in gluconeogenesis, was significantly down-regulated, along with lower levels of its product (fructose-6-phosphate) and higher levels of its substrate (fructose-1,6-bisphosphate) in the kidney of 6-22 week-old CSE^-/- mice. We have also observed lower levels of the gluconeogenic regulator, peroxisome proliferator-activated receptor-&gamma; coactivator (PGC)-1&alpha;, and its down-stream targets, FBPase-1 and -2, phosphoenolpyruvate carboxykinase (PEPCK), and estrogen-related receptor (ERR)&alpha; mRNA expression levels in renal extracts from 6-22 week-old CSE^-/- mice. Likewise, FBPase-1 and -2 mRNA levels were also significantly down-regulated in aorta tissues from 14-16 week-old CSE^-/- mice. Administration of 30 and 50 &#x00B5;M NaHS induced a significant increase in FBPase-1 and PGC-1&alpha; in rat A-10 cells. We have also observed a significant up-regulation of PEPCK and ERR&alpha; mRNA expression levels in 50 &#x00B5;M NaHS-treated A-10 cells, further confirming the involvement of H₂S in regulating the rate of gluconeogenesis and MG formation. Overall, this unique study demonstrates the existence of a negative correlation between MG and H₂S in the vasculature. Further elucidation of this cross-talk phenomenon between MG and H₂S could lead to more elaborate and effective therapeutic regimens to combat metabolic syndrome and its related health complications.</p>

Coronary artery stent placement has been a significant advance in the percutaneous treatment of atherosclerotic disease, and tissue engineered vascular grafts may provide a viable alternative to autologous segments for small diameter vessels. However, in-stent restenosis remains an important limitation, and tissue engineered grafts have poor patency and high risk of thrombus formation due to their inability to maintain a confluent, adherent, and quiescent endothelium. While animal models provide insight into the pathophysiology of these situations, elucidation of the relative importance of stent or graft components, hemodynamic factors, and molecular factors is difficult. Very little research has focused on bridging gaps in knowledge concerning blood/biomaterial interactions, blood/endothelial cell interactions, and endothelial cell/smooth muscle cell cross-talk. The work presented within this thesis will do just that. The objective of this thesis research was to elucidate the influence of biomaterial-induced activation of leukocytes on endothelial cell or smooth muscle cell phenotype, as well as endothelial cell/smooth muscle cell cross-talk in co-culture systems. Towards this goal, two complimentary in vitro endothelial cell/smooth muscle cell co-culture models with divergent smooth muscle cell phenotype were developed and characterized. Using these systems, it was found that the presence of more secretory smooth muscle cells (as would be seen in wound healing or disease) in general enhanced endothelial cell activation in response to biomaterial-pretreated monocytes, while the presence of less secretory smooth muscle cells (to model more quiescent smooth muscle cells found in uninjured healthy vessels) suppressed endothelial cell activation in response to biomaterial-pretreated monocytes (and neutrophils to a small degree). Additionally, biomaterial-pretreated monocytes and neutrophils amplified a smooth muscle cell phenotypic shift away from a more quiescent state. It is likely that the compounding effect of secretory smooth muscle cells and biomaterial-activated leukocytes are responsible for altered vascular wound healing upon implantation of stents or vascular grafts. Understanding the specific signals causing these effects, or signals delivered by contractile smooth muscle cells that limit these effects help to provide design criteria for development of devices or grafts capable of long term patency.

One of the major causes of death in developed countries is cardiovascular disease that affects small and medium sized blood vessels. In most cases autologous grafts have to be used which have limited availability. A functional tissue engineered vessel can be the ultimate solution for vascular reconstruction. Tissue engineered constructs with cells growing in an organized manner have been shown to have improved mechanical properties. In the present study collagen scaffolds with 650 nm, 500 nm and 332.5 nm wide channels and ridges were seeded with human vascular smooth muscle cells (VSMC) and human endothelial cells seperately and then co-cultured on tubular scaffolds. When the films were seeded with endothelial cells it was observed that nanopatterns do not affect cell proliferation or initial cell alignment / however, they significantly influenced cell retention under shear (fluid flow). While 35 &plusmn / 10 % of the cells were retained on unpatterned films, 75 &plusmn / 4 % was retained on 332.5 nm patterned films and even higher, 91 &plusmn / 5 % was retained on 650 nm patterned films. It was shown that nanopatterns as small as 332.5 nm could align the vascular smooth muscle cells (VSMC) and that alignment significantly improved mechanical properties. Presence of nanopatterns increased the ultimate tensile strength (UTS) from 0.55 &plusmn / 0.11 on Day 0 to as much as 1.63 &plusmn / 0.46 MPa on Day 75, a value within the range of natural arteries and veins. Similarly, Young&amp / #8217 / s Modulus values were ca. 4 MPa, again in the range of the natural vessels. Since the films would be ultimately rolled into tubes of collagen, nutrient transfer through the films is quite crucial. Diffusion coefficient for 4-acetaminophenol and oxygen through the collagen films were found to be 1.86 &plusmn / 0.39 x 10-7 cm2.s-1 and 5.41 &plusmn / 2.14 x 10-7 cm2.s-1, repectively in the unseeded form, and increased by 4 fold after cell seeding, which is comparable to that in natural tissues. When both cell types were co-cultured on the nanopatterned tubes (a both-side nanopatterned collagen tube), it was shown that on the outside of the tube VSMCs proliferated in an oriented manner and on the inside endothelial cells proliferated as a monolayer. Therefore, this study showed that cell guidance enhances the mechanical properties of engineered vessels, and help overcome the two most important challenges in vascular tissue engineering / the need for adequate mechanical properties and continuous lining of endothelial cells even under physiological shear stress.

Understanding the mechanisms of cardiovascular disease progression is essential in developing novel therapies to combat this disease that contributes to 1 in 3 deaths in the United States every year. Endothelial dysfunction and its effects on vessel growth and remodeling are key factors in the progression and localization of atherosclerosis. Much of our understanding in this area has come from in-vivo and in-vitro experiments however perfused organ culture systems provide an alternative approach. Organ culture systems can provide a more controlled mechanical and biochemical environment compared to in-vivo models. This study focused on furthering development of this organ culture model by introducing a novel device to produce flow waveforms at the high frequencies and low mean flows seen in the mouse model. The device is capable of monitoring pressure, flow, diameter, and nitric oxide release. Each individual mechanism in the system was integrated via a computer using a custom Labview interface. The performance of the device was characterized by developing physiologic, physiologic-oscillatory, low, low-oscillatory waveforms and sinusoidal waveforms at frequencies ranging from 1-10 Hz. Overall this system provides a robust model to test the effects of flow on various biological markers both in real-time and after culture.

Thesis (Ph. D.)--University of Oklahoma. / Bibliography: leaves 147-164.

Thesis (Ph. D.)--University of Missouri--Columbia, 2001. / "May 2001." Typescript. Vita. Includes bibliographical references (leaves 176-195). Also available on the Internet.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (leaves 118-135).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 106-135).

Airway remodeling in asthma includes alterations in extracellular matrix and airway smooth muscle (ASM) mass. For this study, ASM cells were obtained from rats that were challenged with ovalbumin (OVA) or saline (SAL) as control. OVA and SAL cells were seeded on plastic control (PC) or on plates coated with decorin or biglycan. OVA cell number was significantly increased versus SAL cells, for cells seeded on PC (48 h). A significant decrease in cell number was observed for both OVA and SAL cells seeded on decorin compared to PC cells (48 h). OVA cells, however, showed a more modest reduction in cell number. Furthermore, biglycan decreased SAL cell number only. Compared to no strain (NS), mechanical strain (S) reduced cell number for OVA and SAL cells on all matrices. In addition, S up-regulated expression of beta 1-integrin relative to NS controls. Results suggest an ability of ASM cells to be modulated by matrix and mechanical stimulation.