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<p> Studies examining the characteristics of membranes that facilitate and affect fusion are central to understanding the intricacies of inter- and intra-cellular fusion processes and expanding the existing knowledge of other roles membranes may have. In this thesis a model membrane system, using Sendai Virus and Egg phosphatidylcholine (EggPC) liposomes containing the receptor glycophorin A (proteoliposomes), was used in examining different fusion with proteoliposomes prepared by different methods. For the first time glycophorin A was incorporated into EggPC liposomes vectorially. This was accomplished separately with two detergents: octylglucoside and CHAPS. Fusion of Sendai Virus with the reconstituted proteoliposomes revealed that octylglucoside reconstituted proteoliposomes exhibited lower fusion compared with CHAPS reconstituted proteoliposomes. Efforts to determine the basis for this difference, using either proteinase K or O-glycosidase digestion and subsequent fragment analysis using SDS-PAGE and silver-staining, were inconclusive. A separate study examined the ability of large membrane-anchored biopolymers (chosen in virtue of their large hydrophilic domains) to sterically stabilize Egg PC liposomes. Glycophorin A, the lipophosphoglycan (LPG) from Leishmania donovani, and a polyethyleneglycol-conjugated phospholipid (PEG5000-PE) were incorporated into Egg PC liposomes. In each case, binding of a soluble fluorescent probe, NeutrAvidin Oregon Green, to liposomes containing biotin-conjugated lipid was restricted. This supports the idea that large membrane-anchored biopolymers are able to sterically stabilize liposomes.</p> / Thesis / Master of Science (MSc)

Poly(dimethylsiloxane) (PDMS) fluids containing magnetite nanoparticles stabilized with carboxylic acid-functionalized PDMS were prepared. PDMS-magnetite complexes were characterized using transmission electron microscopy, elemental analysis, and vibrating sample magnetometry. PDMS-magnetite complexes containing up to 67 wt% magnetite with magnetizations of ~52 emu gram-1 were prepared. The magnetite particles were 7.4 ± 1.7 nm in diameter. Calculations suggested that the complexes prepared using mercaptosuccinic acid-functionalized PDMS (PDMS-6COOH) complexes contained unbound acid groups whereas the mercaptoacetic acid-functionalized PDMS (PDMS-3COOH) complexes did not. Calculations showed that the PDMS-3COOH and PDMS-6COOH covered the same surface area on magnetite. Calculations were supported by molecular models and FTIR analyses. The complexes were dispersed into PDMS carrier fluids by ultrasonication, resulting in magnetic PDMS fluids with potential biomedical applications. Magnetite particles (100 nm to 1 mm in diameter) were prepared by crystallization from goethite/glycol/water solutions under pressure. Two methods for particle growth were investigated in which the crystallization medium was varied by adjusting the amount of water or by adding itaconic acid. Particle surfaces were analyzed by x-ray photoelectron spectroscopy (XPS). Particles with clean surfaces were coated with carboxylic acid-functionalized poly(e-caprolactone) stabilizers. Adding itaconic acid to the reactions afforded particles ~100 nm in diameter. The magnetite particles displayed magnetic hysteresis. The particles were dispersed into vinyl ester resins by ultrasonication and it was demonstrated that the ~100 nm particles remained dispersed for three days without agitation. These dispersions have applications in magnetic induction heating for composite repair. Living polymerizations of hexamethylcyclotrisiloxane were terminated with dimethylchlorosilane, phenylmethylchlorosilane, or diisopropylchlorosilane (DIPCS). Platinum-catalyzed hydrosilation of the hydrosilane-terminated PDMS with allyloxyethanol afforded a systematic series of hydroxyalkyl-terminated PDMS. The reactions were successful except for the hydrosilation of the sterically-hindered DIPCS-functionalized PDMS where no reaction was observed. Hydroxyalkyl-terminated PDMS oligomers were successful in initiating the stannous octoate-catalyzed copolymerization of e-caprolactone, which afforded PDMS-b-PCL diblock copolymers of controlled composition. / Ph. D.

The work presented in this thesis focuses on the design and testing of a casualty extraction robot intended to stabilize the head and neck of an unresponsive person. The employment of robots in dangerous locales such as combat zones or the site of a natural disaster has the potential to help keep first responders out of harm's way as well as to improve the efficiency of search and rescue teams. After a review of robotic search and rescue platforms the Semi-Autonomous Victim Extraction Robot(SAVER) is introduced. The necessity of a device intended to support the head and cervical spine during transport on a rescue robot is then discussed. The kinematic and dynamic analyses of various candidate differential mechanisms intended for the head stabilization device are described, and the chosen mechanism is demonstrated in a proof-of-concept device. Following testing with a simple PID controller, it was determined an advanced feedback controller with disturbance rejection capabilities was required. Linear Active Disturbance Rejection Control (LADRC) was chosen for its effectiveness in rejecting perturbations and handling modeling uncertainties. The performance the proposed LADRC control scheme was compared with PID in simulation and the results are presented. Finally, a prototype of the device was designed and built to validate the functionality of the subsystem, and the results of the corresponding experimentation are discussed. / M. S. / Robots can help to keep first responders and medics out of dangerous situations by performing the rescue operation themselves or by collaborating with the field medic to make the process quicker and more efficient. The work presented in this thesis begins with a review of state-of-the-art rescue robots followed by the a brief description of the design of a Semi-Autonomous Victim Extraction Robot (SAVER) intended to rescue injured and incapacitated people. After the SAVER system is briefly described, the necessity of a device intended to support the head and cervical spine during transport is discussed. The head stabilization subsystem could also be implemented as a standalone device for use by paramedics to help free up valuable time that would otherwise be spent in manually stabilizing the head and neck of the injured person

Since World War II, the military has sought methods for rapid stabilization of weak soils for support of its missions worldwide. Over the past 60 years, cement and lime have consistently been found to be among the most effective stabilizers for road and airfield applications, although recent developments show promise using nontraditional stabilizers. The purpose of this research is to determine the most effective stabilizers and dosage rates of stabilizers to increase the strength of soft clay soils (initial CBR = 2) within 72 hours for contingency airfields to support C-17 and C-130 aircraft traffic. Pavement design charts for various aircraft loading conditions were generated using the Pavement-Transportation Computer Assisted Structural Engineering Program, which was developed by the Engineering Research and Development Center to determine ranges of required strength and thickness for an underlying subbase layer and a top base layer, such as stabilized soil, crushed-aggregate, or aluminum matting. From laboratory studies, the required design strengths for many loading conditions were achieved by treating clay with 2%-4% pelletized quicklime for the underlying subbase layer, and treating clay with 2%-4% pelletized quicklime, 1% RSC15 fibers, and 11% Type III cement for the top base layer. While the base layer requires a minimum thickness of six inches, the required subbase layer thickness is often quite large and may be difficult to construct. However, newly developed construction equipment currently used for subgrade stabilization on civilian projects should be able to stabilize the soil down to these large required depths and make construction possible. / Master of Science

This study tests the relationship between certain economic scenarios and the state of the economy in regard to inflation and recession. Using data gathered from government publications, the economy was divided into periods of inflation, recession, and recession recovery. These periods were regressed against variables representing four schools of economic thought: monetarist scenario, structural scenario, power scenario, and micro, or supply side scenario. This study concludes that because of the complex nature of the economy, all representative variables have both positive and negative effects on the economy and no one scenario holds the key to economic stability.

Title: The use of the screening test with the neuro-orthopedic equipment Propriomed in diagnostics of postural stabilization and postural dysfunction. Aim of the work: The aim of this work was to find out whether it is possible to use the provocation test with the neuro-orthopedic equipment Propriomed in the diagnostics of dysfunction of postural stabilization. Methods: With each proband, after briefing, the provocation test on Posturomed, measured in the program Microswing 6 in mode "Stand - Schritt - Messung," was performed three times. The obtained data were evaluated by the program Posturomed Commander by means of eight parameters. The median of the eighth parameter evaluating the resultant total postural stabilization (calculated from three measurements in the program Microsoft Office Excel 2007) was used to divide probands into a group of those posturally stable (n=19) and a group of those with mild postural dysfunction (n=30). With each proband, the provocation test with Propriomed, measured in the program Microswing 5 in mode "Propriomed Körper 4 - fach," was also performed three times after briefing. The obtained data were evaluated by the program Microswing 5 and the median of the resultant total postural stabilization was also calculated from them. In two research groups, we compared the...

Woodlot and natural woodland systems in the semi-arid regions in Tanzania are believed to have a high potential to sequester carbon (C) in their biomass and the soil which may qualify for C credits under the current voluntary C market schemes like, the REDD program. However, our understanding of the processes influencing storage and dynamics of C in soils under semi-arid agroforestry systems such as these woodlot systems is limited. This study evaluated C pools in soil and tree biomass in woodlot species of Albizia lebbeck, Leucaena leucocephala, Melia azedarach, and Gmelina arborea; and in farmland and ngitili systems. Synchrotron-based C K-edge x-ray absorption near-edge structure (XANES) spectroscopy was also used to study the influence of these land use systems on the soil organic matter (SOM) chemistry to understand the mechanisms of soil C changes. Soil samples were collected to 1 m depth and subsamples for each land use system to 0.4 m depth were fractionated into macroaggregates (2000-250 μm), microaggregates (250-53 μm), and silt and clay-sized aggregates (<53 μm) to provide information of C dynamics and stabilization in various land uses. SOC was analyzed in whole and soil aggregates and biomass C was estimated using developed biomass models from the literatures. Aboveground biomass carbon in the woodlots from the Kahama district ranged from 11.76 Mg C ha-1 to 24.40 Mg C ha-1. Based on the age of woodlots and the rate of carbon sequestration potential (CSP), Gmelina arborea had the highest rate of aboveground C sequestration (3.59 Mg C ha-1 year-1). The SOC stocks in whole soil for the land use systems from the two districts ranged from 43-67 Mg C ha-1. The degraded ngitili did not show a reduction in SOC stocks despite reducing aboveground biomass C stocks by 15.11 Mg C ha-1. SOC in the woodlots were found to be associated more with the micro and silt-and clay-sized aggregates than the macroaggregates, reflecting high stability of SOC in the woodlot systems. The XANES C K-edge spectra revealed the stabilization of recalcitrant aromatic C compounds in the silt and clay-sized aggregates. This study demonstrates the significant contributions of woodlots in biomass C accumulation as well as long-term SOC stabilization in soil fractions. Thus, these agroforestry practices hold promise to meet household energy needs while contributing to climate change mitigation and adaption.

This thesis addresses the problem of designing and evaluating passive satellite attitude control systems for small satellites. Passive stabilization techniques such as Gravity Gradient stabilization, Passive Magnetic Stabilization, and Aerodynamic stabilization in Low Earth Orbit utilize the geometric and magnetic design of a satellite and the orbit properties to passively provide attitude stabilization and basic pointing. The design of such stabilization systems can be done using a high fidelity simulation of the satellite and the environmental effects in the orbit under consideration to study the on-orbit behavior and the effectiveness of the stability system in overcoming the disturbance torques. The Orbit Propagator described in this thesis is developed to include models for orbit parameters, Gravity Gradient torque, Aerodynamic Torque, Magnetic Torque, and Magnetic Hysteresis Material for angular rate damping. Aerodynamic stabilization of a three-unit CubeSat with deployable side panels in a “shuttlecock” design is studied in detail. Finally, the Passive Magnetic Stabilization system of KySat-1, a one-unit CubeSat, is also described in detail and the simulation results are shown.