Transposons are DNA segments that can move or transpose themselves to new positions within the genome of an organism. Biologists need to predict preferred insertion sites of transposons to devise strategies in functional genomics and gene therapy studies. It has been found that the deformability property of the local DNA structure of the integration sites, called Vstep, is of significant importance in the target-site selection process. We considered the Vstep profiles of insertion sites and developed predictors based on Artificial Neural Networks (ANN) and Support Vector Machines (SVM). We trained our ANN and SVM predictors with the Sleeping Beauty transposonal data, and used them for identifying preferred individual insertion sites (each 12bp in length) and regions (each 100bp in length). Running a five-fold cross-validation showed that (1) Both ANN and SVM predictors are more successful in recognizing preferred regions than preferred individual sites; (2) Both ANN and SVM predictors have excellent performance in finding the most preferred regions (more than 90% sensitivity and specificity); and (3) The SVM predictor outperforms the ANN predictor in recognizing preferred individual sites and regions. The SVM has 83% sensitivity and 72% specificity in identifying preferred individual insertion sites, and 85% sensitivity and 90% specificity in recognizing preferred insertion regions.

This thesis presents the design and development of a novel two-axis micromirror utilizing electrostatic, repulsive-force rotational actuators for laser scanned vector display systems. The micromirror consists of a 1.0 mm reflective mirror plate that can be rotated at high speeds to steer a laser beam to generate images. Fabricated using PolyMUMPs, the micromirror is operated in a non-resonant mode between 0 V and 200 V and can achieve a maximum optical scanning angle of ±2.6° in each axis with a settling time as fast as 2.75 ms and a first resonant frequency of 1400 Hz. Open-loop control methods were developed for image correcting and improving image quality. The micromirror was integrated into a portable, handheld vector display device which included designing and developing driving circuits, device firmware, mechanical components and optical components.

This thesis presents the design and development of a novel two-axis micromirror utilizing electrostatic, repulsive-force rotational actuators for laser scanned vector display systems. The micromirror consists of a 1.0 mm reflective mirror plate that can be rotated at high speeds to steer a laser beam to generate images. Fabricated using PolyMUMPs, the micromirror is operated in a non-resonant mode between 0 V and 200 V and can achieve a maximum optical scanning angle of ±2.6° in each axis with a settling time as fast as 2.75 ms and a first resonant frequency of 1400 Hz. Open-loop control methods were developed for image correcting and improving image quality. The micromirror was integrated into a portable, handheld vector display device which included designing and developing driving circuits, device firmware, mechanical components and optical components.

No description available.

No description available.

No description available.

Lentiviral gene therapy has held great promise for treating a wide range of neurological disorders due to its ability to stably integrate into the genome of nondividing cells like neurons, in addition to dividing cells. The nervous system is a complex and highly heterogeneous system, and while a therapeutic intervention may have beneficial effects in one population of cells it may have severe side effects in another. For this reason, specific targeting of lentiviral vectors is crucial for their ultimate utility for research and clinical research use. Two different approaches for focusing the targeting of lentiviral vectors were employed in these studies. The first method involved assessing the effects of vector production strategies on the resulting virus’s tropism both in vivo and in vitro. The changes in vector transduction were determined via flow cytometry on cells in culture and immunohistochemistry following brain injections. Results from these experiments suggest that while the production conditions do impact the vectors efficacy, there is not a distinct effect on their tropism. A unique characteristic of retroviral and lentiviral vectors is their capacity for being pseudotyped, conferring a new tropism on the vector. Native tropisms are generally not specific beyond very broad cell types, which may not be sufficient for all applications. In this case, chimeric targeting molecules can provide an even more refined targeting profile compared to native pseudotypes. The second approach utilizes novel chimeric glycoproteins made from nerve growth factor and the vesicular stomatitis virus glycoprotein. These chimeras are designed to pseudotype lentiviral vectors to target nociceptive sensory neurons for a variety of disorders. While these chimeras were successfully produced as protein, they were misfolded and sequestered in the endoplasmic reticulum and therefore unavailable to produce lentivirus. While neither strategy was completely successful, they do provide interesting information for the design and creation of lentiviral vectors. This research shows that small differences in the steps followed as part of a lentivirus production protocol can greatly impact the resulting vectors efficacy. It also shows that while VSV has been used to create chimeric glycoproteins, not all targeting molecules are suitable for this purpose.

Uninfected larvae of Ixodes dammini, lxodes cookei, and Amblyomma americanum were fed on hamsters that had been injected intraperitoneally with a 0.5.ml sample of Borrelia burgdorferl (2.5 X 107 spirochetes per ml) 21 days earlier. A total of 108 of these larvae comprised of 36 1. dammini, 36 i. cookei, and 36 A. americanum were aseptically dissected and examined by darkfield and immunofluorescent microscopy for the presence of B. burgdorferl within 48 hours of feeding on the B. burgdorferi infected hamsters. The removal and examination of the midgut diverticula revealed that 32/36 (88.9%) of the l. dammini larvae contained B. burgdorferl. Only 5/36 (13.9%) of the l. cookei larvae and 7/36 of the A. americanum larvae harbored spirochetes in their midgut diverticula.A portion of the nymphs that molted from the above larvae were also dissected and examined by darkfleld and indirect immunofluorescent techniques. Borrelia burgdorferi were observed in the midgut diverticula of 94/107 (87.8%) of the l. dammini nymphs. None of the 30 (0%) l. cookei nymphs examined were found positive for spirochetes and only 1/60 (1.7%) of the A. americanum nymphs was found positive for B. burgdorrerl.A total of 83 lL dammini, 53 A. americanum, and 161. cookei nymphs reared from larvae that fed to repletion on hamsters infected with B. burgdorrerl were allowed to feed on uninfected hamsters to assess transmission of B. burgdorrerl. Transmission was demonstrated only by the l. dammlnl nymphs. The findings of this study suggest that it is extremely unlikely that l. cookei can serve as a vector for B. burgdorrerl, but do not rule out completely the possibility that A. americanum may be able to maintain B, burgdorrerl infections transstadially and, under certain conditions, transmit the organisms to vertebrate hosts. / Department of Physiology and Health Science

Uninfected nymphs of Ixodes scapularis and Amblyomma americanum were fed on hamsters that had been injected intraperitoneally with a 0.5 ml sample of Borrelia burgdorferi (2.5 X 10' spirochetes per ml) 30 days earlier. All nymphs fed to repletion and were then housed during the molting process. In order to assess their ability to transmit the spirochetes, the resulting l. scapularis and A. americanum adults were allowed to feed on uninfected rabbits.Dissection of the adult l. scapularis ticks revealed 9/12 (75%) to harbor motile spirochetes, identified as B. burgdorferi by darkfield microscopy, isolation in BSK II medium, and indirect immunofluorescent antibody staining with the monoclonal antibody H5332. Transmission was successful to one of two New Zealand White rabbits by these infected ticks.Dissection of the adult A. americanum ticks revealed 0/150 (0%) to harbor spirochetes. Transmission to each of three rabbits was unsuccessful. However, 5/90 (5.6%) cultures of midgut material from these same ticks, harbored non-motile spirochete-like bodies. The identity of these "spirochetes" is unknown. / Department of Biology

The focus of this thesis is to investigate the implementation of Radio Frequency (RF) In-Phase and Quadrature-Phase (I/Q) vector modulation through the use of modern photonic components and sub-systems which offer extremely wide RF intrinsic bandwidths. All-electronic vector modulators suffer from frequency coverage limitations and amplitude and phase instability due to components such as phase shifters and variable gain controllers operating at or near 100\% bandwidth. In stark contrast, once an RF signal has been modulated onto an optical carrier, the percent bandwidth of the RF to carrier is typically less than 0.01\% percent. The fundamental mechanisms and basic electronic and photonic components needed to achieve vector modulation is introduced first. The primary electrical component required in most architectures is the 90° RF hybrid coupler, which is required to generate the RF I and Q terms. The two primary photonic building blocks, aside from the laser, electro-optic modulator and demodulator, are Mach-Zehnder Modulators (MZM) and Variable Optical Attenuators (VOA). Through the utilization of these components, multiple past architectures are explored and multiple new architectures are designed simulated. For each architecture, there is a discussion on the practical implementation. Considerations such as system complexity, integration, and sensitivity to unwanted environmental stimuli are taken into account with potential solutions to alleviate these risks. In closing, the noise figure and its impact on Spur-Free Dynamic Range (SFDR) for a basic RF photonic link is derived to provide a system-level figure of merit that can be used, in most RF applications, to determine the overall performance utility current and future designs.