Specimens of Citharichthys stigmaeus, the speckled sanddab, were taken from Yaquina Bay, Newport, Oregon and exposed for eight days to dissolved measured concentrations ranging from 2.9 μg/l to 190 μg/1 of the polychlorinated biphenyl, Aroclor® 1260. Oxygen consumption was measured to determine any change from routine levels of respiration. This research produced the following conclusions: 1) a relationship exists between oxygen consumption and measured concentrations of Aroclor® 1260 in the water as demonstrated by high negative partial correlations and subsequent significant water concentration terms in the regression equations for two of the four experiments: also, a relationship exists between oxygen consumption and tissue concentration of Aroclor® 1260 as demonstrated by high negative partial correlations and subsequent significant tissue concentration terms in the regression equations for three out of four experiments, (because of the inherent variability in oxygen consumption measurements and difficulties of predicting PCB concentrations in both water and tissue, the evidence is difficult to interprete); 2) acetone, used as a solvent for the toxicant, may change oxygen consumption levels and interfere with determining PCB effects; 3) after an eight day dosing period the concentration of Aroclor® 1260 in whole body tissue can be described by the equation: Y = 4.48(1 - e [superscript -.0365x]) where Y is the concentration of Aroclor® 1260 in the tissue and x is the measured Aroclor® concentration in the water; 4) after eight days a constant level of Aroclor® 1260 is present in the tissue if the animal is exposed to water levels of Aroclor® 1260 above approximately 25 μg/1. / Graduation date: 1976

A detailed study of iron concentrations measured by the reducible, reactive ferrous, and extractable methods was conducted in Auke Bay, Alaska during June 1973 and in Hood Canal, Washington during October 1973 and April 1974. The concentrations by each method were generally highest at the bottom and decreased towards the surface with occasional pockets of high iron concentration water at the surface. In Hood Canal in October the maximum reactive ferrous iron concentration was observed at the bottom of the pycnocline. Large changes in the iron concentration were observed between successive surveys. The reducible iron method (range <0.8 to 187 μg Fe/L) measures colloidal ferric hydroxide plus easily dissolvable and reducible organically and inorganically bound iron. The reactive ferrous iron method (range <0.04 to 4.2 μg Fe/L) measures loosely bound organic and inorganic ferrous iron. The extractable iron method, as finally used, (range <4 to 170 μg Fe/L) measures that iron measured by reducible iron method plus up to twice the tightly bound organic iron. We have defined "available" iron (with quotes) as that iron which appears to be taken up by phytoplankton as determined by the correlation between the in situ iron concentration and the chlorophyll a concentration. Chlorophyll a concentration maxima generally occurred at the depth of the iron concentration minima, strongly supporting the idea that each method measures "available" iron. However, significant correlation coefficients for the regression of iron concentration versus chlorophyll a only support the "availability" of reactive ferrous iron and that phytoplankton prefer ferrous iron to ferric iron. This was one of the first extensive uses of Lewin and Chen's (1973) ferrous iron method and values observed were generally 2 to 100 times less than they reported. Changes occurring during water storage appear to be a function of p0₂. Major changes took place during the first five hours of storage. Interstitial water was greatly enriched in iron compared with the overlying water. The ferrous iron concentration was particularly high due to the low Eh of the sediments. Although the net flow of "available" iron is out of the sediment, the flux is small (approximately 3 x 10⁻⁵ μg Fe/m²sec). Most of the iron that appears to be coming from the sediment is probably being produced by bacterial decomposition as in the case of subsurface sources of iron associated with ammonia or urea maxima. Fresh water is a significant source of extractable and reactive ferrous iron into the well-mixed surface layer. Fresh water is also a source of organically bound iron. Zooplankton appear to produce "available" iron by eating or excretion. Light appears to cause the production of ferrous iron through an undetermined mechanism. / Graduation date: 1976

Recombinant human calpain-5 was expressed in insect cells using a baculovirus system. The expressed calpain-5 was purified by both traditional chromatography and by affinity-column chromatography. Both methods yielded active protease. Calpain-5 displayed very limited hydrophobicity. This indicated that calpain-5 is not a membrane binding protein. Calpain-5 had pI of 8.3. The recombinant calpain-5 also exhibited calcium-dependent proteolytic activity. The calculated calcium requirement for half-maximal activity was 9.6 mM when incubated at 37��C and 26.5 mM when incubated at 30��C. Compared to traditional calpains, which require less than 1 mM calcium for half-maximal activity, calpain-5 exhibited weaker proteolytic activity. This is an unusual observation because calpain-5 lacks the typical calcium-binding domain of the calpains and implied that other calcium-binding region of the protein account for calcium-binding and sensitivity. Our results also showed that calpain-5 was different from traditional calpains because its activity was higher at 37��C compared to 30��C and remained active at 37��C for more than 2 hours. This differs from traditional calpains which display better proteolytic activity at lower temperatures and become inactive within 30 minutes of incubation in 37��C. Calpain-specific inhibitors, calpastatin and E64, did not inhibit calpain-5. Only one calcium-binding inhibitor, PD150606, inhibited calpain-5 proteolytic activity. These results confirmed that calpain's calcium-binding domain is important in calpastatin binding and calpain-5 possesses other calcium-binding regions. Calpain-5 was able to degrade spectrin, a ubiquitous cytoskeletal protein. This indicates that calpain-5 might have a role in cell remodeling. Finally, calpain-5 has the ability to degrade itself. It is not clear if this is the result of inter- or intra-molecular proteolysis and whether this leads to activation of the protein or is, instead, the first step in its degradation. Calpain-5 is expressed at highest concentrations in testis, brain, liver and gastrointestinal tract. It is not clear why these tissues require a unique calpain. Calpain-5 may provide these tissues with an additional calcium-dependent proteolytic activity which is not regulated by calpastatin and which could participate in cytoskeletal protein turnover. / Graduation date: 2004

Graduation date: 1995

Not available

Whole-body vibration (WBV) has been shown to enhance vertical jump performance. The purpose of this study was to determine which WBV intensity has the greatest effect on counter movement jump (CMJ) height and the duration of that affect. Forty-four participants, of varying training statuses, were tested. They participated in > 4 familiarization sessions, to eliminate learning effects. Participants performed a pre-test, followed randomly by one of 5 WBV intensities. Participants performed 3 maximal CMJs immediately, 5, and 10 min following treatment. The best performance was used and calculated as a percentage of the pre-treatment values. A multivariate model (treatment X time X gender) was used to analyze the data. The three-way interaction approached significance (p=0.053) and significance was found for all two way interactions. Females performed the best immediately following the 2.71g treatment (116.9 + 38.4%). Male participants did not increase their performance; however, they may require longer durations of vibration exposure to elicit effects. The differences between males and females may also indicate that the effects of WBV are dependent on strength, stiffness, and/or training levels. Future research should continue to systematically investigate the effects of vibration and participant characteristics on WBV and performance.Keywords: power, frequency, amplitude, training, potentiation, stiffness. / School of Physical Education, Sport, and Exercise Science

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / Dental Materials Science / Master / Master of Science in Dental Materials Science

published_or_final_version / abstract / toc / Clinical Psychology / Master / Master of Social Sciences

No description available.