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Effects Of Diabetes And Aging On Posture And Acceleration Thresholds During Lateral Translations, Samantha Jean Richerson

Doctoral Dissertations

Research objectives. One source of falls in the elderly may be an inability to sufficiently adjust to transient postural perturbations or slips. Identifying useful predictors of fall potential, as well as factors that affect the ability of an individual to detect a movement of the standing support surface may provide insight into postural stability and methods to increase stability in elders. To do this, acceleration thresholds to short, precise, lateral platform translations and the resultant psychophysical responses of adults with early Type 2 diabetes to age-matched controls and young adults were measured.

Methods. Using an innovative SLIP-FALLS platform, …

Free Solution Electrophoresis Measurements And Their Theoretical Relationships To Net Protein Valence, Jennifer A. Durant

Doctoral Dissertations

Biochemical solutions are composed to a large degree of charged molecules (proteins, DNA, dissolved salts, etc) which can interact and therefore exert a force on each other. Analytical determination of the valence of biological macro-ions contributes to our understanding of the forces involved in both intra- and inter-molecular interactions. This dissertation uses two free solution techniques, membrane confined electrophoresis (MCE) and capillary electrophoresis (CE), to study valence in the context of a series of charge mutants of T4 lysozyme and RNase Sa. The use of these mutants allows attribution of the changes in electrophoretic behavior entirely to changes in charge. …

Hydrodynamic Behavior And Thermal Stability Of A Pegylated Protein: Studies With Hen Egg Lysozyme, Yatin R. Gokarn

Doctoral Dissertations

We studied the effect of covalent attachment of polyethylene glycol (PEGylation) on the hydrodynamic behavior and thermal stability of a model protein---Hen Egg Lysozyme (HEL). HEL was modified with a linear, 20-kD, PEG to produce mono (PEG1-HEL), di (PEG2-HEL), and triPEGylated (PEG3-HEL) species.

The hydrodynamic properties of HEL were altered upon PEGylation. A decrease in sedimentation (s) and diffusion (D) coefficients was observed for all three PEG-HEL molecules in comparison to HEL (1.81 s). Despite differences in molecular weights of the PEG-HEL molecules (∼34, 55 and 80 kD), their s values were very close (1.0--1.1 s). Significant hydrodynamic non-ideality was …