Thesis (M.S.)--University of Michigan, 1978.

Thesis (M.S.)--University of Michigan, 1959. / Project completed in 1958. Degree awarded in 1959.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 159-164). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 159-164). Also available on the Internet.

Thesis (Ph. D.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 129-135).

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The applicability of an isotopically labelled assay system to determine the lipase production in Pseudomonas aeruginosa was evaluated. Supernatant from cultures of Pseudomonas aeruginosa grown in a medium containing olive oil was incubated with a substrate containing labelled trioleate. Fatty acids were isolated by means of a liquid-liquid partition system. Enzyme activity was determined by measuring the amounts of free fatty acid by liquid scintillation counting. Findings indicate that the isotopicallylabelled, liquid-liquid partitioning assay is reliable, sensitive and adaptable to rapid assay conditions. It was also determined that different strains of Pseudomonas aeruginosa produce varying amounts of lipase. Partial purification of supernatant by gel filtration produced two protein peaks showing enzymatic activity.

In this thesis, manufacturing of microirradiators, electrodeposition of radioactive elements such as Ni-63, and applications of these radioactive sources are discussed. Ni-63 has a half life of 100 years and a low energy beta electron of 67 keV, ideal for low dose low linear energy transfer (LET) research. The main focus of the research is on the novel Ni-63 microirradiator. It contains a small amount of total activity of radiation but a large flux, allowing the user to safely handle the microirradiator without extensive shielding. This thesis is divided into nine chapters. Properties of microirradiators and various competing radioactive sources are compared in the introduction (chapter 1). Detailed description of manufacturing Ni-63 microirradiator using the microelectrode as the starting point is outlined in chapter 2. The microelectrode is a 25 µm in diameter Pt disk sealed in a pulled 1 mm diameter borosilicate capillary tube, as a protruding wire or recessed disk microelectrode. The electrochemically active surface area of each is verified by cyclic voltammetry. Electrodeposition of nickel with a detailed description of formulation of the electrochemical bath in a cold "non-radioactive setting" was optimized by using parameters as defined by pourbaix diagrams, radioactive electroplating of Ni-63, and incorporation of safety regulations into electrodeposition. Calibration and characterization of the Ni-63 microirradiators as protruding wire and recessed disk microirradiators is presented in chapter 3. In chapters 4 through 6, applications of the Ni-63 microirradiators and wire sources are presented. Chapter 4 provides a radiobiological application of the recessed disk microirradiator and a modified flush microirradiator with osteosarcoma cancer cells. Cells were irradiated with 2000 to 1 Bq, and real time observations of DNA double strand breaks were observed. A novel benchtop detection system for the microirradiators is presented in chapter 5. Ni-63 is most commonly measured by liquid scintillation counters, which are expensive and not easily accessible within a benchtop setting. Results show liquid scintillation measurements overestimates the amount of radiation coming from the recessed disk. A novel 10 µCi Ni-63 electrochemically deposited wire acting as an ambient chemical ionization source for pharmaceutical tablets in mass spectrometry is in chapter 6. Typically, larger radioactive sources (15 mCi) of Ni-63 have been used in an ambient ionization scenario. Additionally, this is the first application of using Ni-63 to ionize in atmosphere pharmaceutical tablets, leading to a possible field portable device. In the last chapters, chapters 7 through 8, previous microirradiator experiments and future work are summarized. Chapter 7 illustrates the prototype of the electrochemically deposited microirradiator, the Te-125 microirradiator. In conjunction with Oak Ridge National Laboratory, Te-125m is a low dose x-ray emitting element determined to be the best first prototype of an electrochemically deposited microirradiator. Manufacturing, characterization, and experiments that were not successful leading to the development of the Ni-63 microirradiator are discussed. In chapter 8, future work is entailed in continuing on with this thesis project. The work presented in the thesis is concluded in chapter 9.

The design of biomaterials, historically initiated and developed by physicians and engineers, in the last decades has slowly shifted toward a more biochemical based approach. For the replacement, repair and regeneration of tissues scientists are now focusing on materials that stimulate specific biological response at the molecular level. These biomaterials have already shown interesting applications in cell proliferation, differentiation, and extracellular matrix production and organization when the material modifications are designed to elicit specific interactions with cell integrins. In the present work we propose the application of this strategy for the development of blood-compatible materials. We first identified, in the coagulation cascade a key enzyme that constitute a valuable biological target for the development of anti-thrombogenic compounds. Piperazinyl-amide derivatives of N-alfa-(3-trifluoromethyl-benzenesulfonyl)-L-arginine were synthesized as graftable thrombin inhibitors. These inhibitors provided a spacer arm for surface grafting and a fluorine tag for XPS (X-ray photoelectron spectroscopy) detection. The possible disturbance of biological activity due to a variable spacer-arm fixed on the N-4 piperazinyl position was evaluated in vitro against human alfa-thrombin, in silico by molecular modelling and via X-ray diffraction study. Selected inhibitors, having inhibition potency in the mM range, were grafted on polyesters surface via wet chemistry and photochemical activation treatments. Wet chemistry surface grafting was performed by specific hydroxyl chain-ends activation and resulted in bioactive molecules fixation of 20-300pmol/cm2. The photochemical grafting was performed using a molecular clip providing an aromatic azide, for nitrene insertion into a polymer, and an activated ester for grafting of tag compounds. This grafting technique resulted in a dramatic increase in fixed bioactive signals (up to nmol/cm2). The material blood-compatibilization induced by the surface fixation of the inhibitors, was measured by a static blood clot weight measurement test. The wet chemistry grafting technique resulted in moderate blood-compatibilization while by the photochemical grafting method important decrease in surface blood clot formation was observed. In the latter case, the blood response to material contact was found to be strongly affected by the polyester surface photo-degradation induced by the activation treatment.