The consequences of ingesting different carbohydrate solutions on fluid movement and availability have not been systematically examined. In addition, the role of carbohydrate in the post-exercise rehydration period has received little attention despite the need for substrate replenishment following exercise and the role of carbohydrates in stimulating water absorption in the intestine. The aims of this thesis were to assess fluid absorption characteristics and availability of solutions containing increasing concentrations of glucose and to evaluate their role in the restoration and maintenance of fluid balance following a period of exercise-induced dehydration. The ingestion of a single bolus of a commercially available hypertonic 18% carbohydrate solution (chapter 3) and a hypertonic 10% glucose solution (chapter 4) resulted in reductions in plasma volume that are most likely due to acute net secretion of water into the intestinal lumen. When investigating recovery of whole body hydration status after sweat loss, a hypertonic 10% glucose-electrolyte solution maintained whole body fluid balance for a longer period than a hypotonic 2% glucose-electrolyte solution and an electrolyte only solution when a fixed volume of fluid was consumed during a rehydration period of one hour following cycle exercise in the heat (chapter 5). When fluid was consumed ad libitum over a two hour period following similar cycle exercise in the heat, a hypertonic 10% glucose-electrolyte solution was as effective in restoring and maintaining fluid balance as a 2% hypotonic glucose-electrolyte solution and an electrolyte only solution (chapter 6). The reduced rate of gastric emptying that accompanies the ingestion of high carbohydrate solutions was likely to be the primary cause for the difference in urine production reported between thetrials during this study (chapter 7). In conclusion, ingestion of hypertonic carbohydrate solutions results in a reduction in extracellular fluid volume that is most likely due to secretion of water into the intestinal lumen and the carbohydrate content of an ingested solution is of importance in the post-exercise rehydration period.

Aquaporin proteins significantly increase water permeability across tissues and cell membranes. Ocular tissues, including the trabecular meshwork (TM) and retinal pigment epithelium (RPE), are especially reliant on aquaporin mediated water movement for ocular homeostasis. Even though bulk fluid movement is paracellular through the TM and transcellular through the RPE, both express aquaporin-1 (AQP1). The role and regulation of AQP1 as it relates to homeostasis in different ocular tissues is not well understood. I hypothesized that ocular tissues respond to external mechanical and molecular cues by altering AQP1 expression and function in order to regulate ocular fluid movement and maintain homeostasis.To test how AQP1 function is altered in response to external cues in order to maintain tissue-specific homeostasis, I addressed the following two aims. The first aim was directed at determining how mechanical strain, an external stimulus that routinely affects TM function, influences AQP1 expression and TM homeostasis. Primary cultures of human TM were subjected to static and cyclic stretch and then analyzed for changes in AQP1 expression by western blot and cell damage by activity of lactate dehydrogense (LDH) in conditioned media. The results show AQP1 expression and LDH release significantly increased with static stretch. Analysis of LDH release with respect to AQP1 expression revealed an inverse linear relationship (r² = 0.7780).The second aim was directed at characterizing signaling mechanisms responsible for regulating fluid transport in RPE, previously shown to be dependent upon AQP1. I treated primary cultures of human RPE with either atrial natriuretic peptide (ANP) or 8-bromo-cyclic guanosine monophosphate (8-Br-cGMP) in the presence or absence of Anantin (ANP-receptor inhibitor) or H-8 (Protein Kinase G inhibitor). The results show that ANP and 8-Br-cGMP significantly increased apical to basal net fluid movement (p < 0.05, n = 3). Inhibition of these effects was successful with Anantin treatment but not with application of H-8.The data presented demonstrate a novel role of protection for AQP1 in TM, and also expand upon cGMP dependent regulation of RPE fluid transport. The combined studies indicate tissue specific AQP1 regulation may offer new avenues to target water movement in treatment of ocular pathologies.

In recent years, repetitive traumatic brain injuries have been linked to the progressive neurodegenerative disorder termed chronic traumatic encephalopathy. However, the mechanical characteristics of brain tissue exposed to repetitive loading still lack understanding. This research evaluated the response of porcine brain tissue undergoing cyclic, compressive loading in reference to three impact parameters: cycle number (N25, N50, N100, N150, and N200), strain level (15, 30, and 40%), and strain rate (0.00625, 0.025, 0.10, and 1.0/s). Following mechanical testing, tissue samples were processed for hematoxylin and eosin (H&E) staining. Stress values, hysteresis energy, and decreases in hysteresis energy for all parameters were compared. The data suggest that microstructural brain tissue damage is highly dependent on strain level and cycle number, whereas strain rate did not appear to cause permanent damage in the quasi-static range applied. The onset of permanent microstructural tissue damage may relate to movement of fluid molecules within the tissue.

The purpose of this research was to investigate the effects of movement instruction on children's singing achievement scores. When controlling for age, four overarching questions and nine sub-questions were asked. First, when controlling for age, how do pitch achievement scores at the outset compare to pitch achievement scores after movement instruction? 1) Is there a significant main effect of type of instruction on children's pitch achievement scores (between subjects)? 2) Is there a significant main effect of time on children's pitch achievement scores (within subjects)? 3) Is there a significant instruction and time interaction? Second, when controlling for age, how do rhythm achievement scores at the outset compare to rhythm achievement scores after movement instruction? 4) Is there a significant main effect of type of instruction on children's rhythmic achievement scores? 5) Is there a significant main effect of time on children's rhythmic achievement scores? 6) Is there a significant instruction and time interaction? Third, when controlling for age, how do singing voice development scores at the outset compare to scores after movement instruction? 7) Is there a significant main effect of type of instruction on children's singing voice development scores? 8) Is there a significant main effect of time on children's singing voice development scores? 9) Is there a significant instruction and time interaction? Fourth, descriptively, what is the effect of gender on students' pretest and posttest pitch achievement scores, rhythm achievement scores, and singing voice development measure scores? Second, third, and fourth grade students (N = 143) participated in the study. Subjects were randomly assigned to one of three treatment groups receiving different instruction: steady beat movement, continuous fluid movement, or a control group receiving no movement instruction. A researcher-designed criterion song was used as a pretest and posttest measure. Pitch and rhythm achievement scores were assessed using Praat Software. Three raters assessed singing performances using Rutkowski's Singing Voice Development Measure. Three split-plot Analyses of Covariance were run on the data. Results indicated that there was a significant interaction between treatment and time on pitch achievement scores. Post hoc analyses revealed no significant differences among treatment groups for pitch achievement scores. Results indicated that there was a significant interaction between treatment and time for Singing Voice Development Measure scores. Post hoc analyses revealed that the treatment group receiving continuous fluid movement significantly outscored the treatment group receiving steady beat movement. No significant differences were found on rhythm achievement scores. Descriptively, females outscored males on pitch, rhythm, and singing voice development measure scores for both pretest and posttest measures. / Music Education