Andrea Baumer

Thesis Title: The Evaluation of a Metabolic Viability Scaling Factor (MVSF) for Clearance Projections in Cryopreserved Heptocytes.

Thesis Abstract: The application of a metabolic viability scaling factor (MVSF) to drug clearance predictions was evaluated with the use of cryopreserved hepatocytes. This scaling factor incorporates the loss of metabolic capacity of the cells over the duration of the experimental determination of intrinsic clearance. Flow cytometry was used to measure the metabolic viability of the cryopreserved hepatocytes throughout the incubation period, and the decrease in percentage of viable cells was used to generate the scaling factor. This method was successfully applied at Pfizer Global Research and Development (PGRD) Ann Arbor, and demonstrated an improvement in drug clearance predictions. The parameters generated by the instrument were then further assessed in their ability to identify metabolically active, viable hepatocyte preparations from inadequate hepatocyte preparations with viabilities under 80%. This was done using two fluorescent probes: propidium iodide (PI) and 5-(and-6)-chloromethylfluorescein diethyl ether (CMFDE). The effects of conditions historically shown to decrease the metabolic capacity of hepatocytes--high organic solvent content and mechanical disruption--were readily detected using these probes.

Future Plans: Andrea is currently in the Pharmacy School at the University of Michigan.

Kari Brewer

Thesis Title: Synthesis and Analysis of Copper Derivatives and Their Electrochemical Properties.

Thesis Abstract: Three copper complexes were synthesized, characterized by UV-visible as well as infrared spectroscopy, and electrochemically analyzed using Cyclic Voltammetry (CV) and Osteryoung Square Wave Voltammetry (OSWV). The first complex, [Cu(II)tacn]Cl₂, was synthesized with a 46.38% yield (0.3993mmol) and successful synthesis was confirmed by UV-visible and infrared spectroscopy. Electrochemistry confirmed E_1/2 values of 524 mV and -316 mV for OSWV with values of 349 mV and -304.5 mV given by CV data. [Cu(II)tacn]Cl₂ was found to be both electrochemically and chemically irreversible. 3.4953 mmol of the second complex, [Cu(II)(PY2)N₃]Cl, was synthesized with a percent yield of 54.16%. The compound was also confirmed by UV-visible and infrared spectroscopy. Two peaks were visible in OSWV and CV voltammograms which gave E_1/2 values of 176 mV and -322 mV for OSWV and 106.5 mV and -219 mV for cyclic voltammetry. The peak with the more positive E_1/2 value displayed properties with electrochemical irreversibility and chemical reversibility while the peak representing the more negative E_1/2 value showed quasi-reversible electrochemical properties with irreversible chemical properties. In addition, [Cu(II)PY2](PF₆)₂ was synthesized at a percent yield of 99.76% and yielded 28.6170 mmol of product. One peak was present with an E_1/2 value of 32 mV for OSWV data and 8.5 mV for CV experimentation. It showed irreversible properties for both electrochemical and chemical activity.

Future Plans: Kari is currently in the Ph.D. Program for Cancer Biology at the University of Texas at Houston-MD Anderson Cancer Center.

Jonathan Dumke

Thesis Title: Development of a Chemiluminescence Detector for Enhanced Sensitivity in Capillary Electrophoresis.

Thesis Abstract: A chemiluminescent detector was built for enhanced sensitivity in capillary electrophoresis. The standard photodiode array detector in the capillary electrophoresis (CE) instrument was not sensitive enough to detect chemiluminescent reactions. A flow injection analysis instrument was used to help with the understanding of chemiluminescent detection. To enhance the detection sensitivity, a side-arm photomultiplier tube was installed to detect the luminescence from 5-amino-2,3-dihydro-1,4-phthalazinedione (luminol), hydrogen peroxide, and horseradish peroxidase. The photomultiplier tube was installed in the place of the CE instrument’s UV lamp, since no lamp is required for chemiluminescence detection. A power supply and amplifier circuit for the photomultiplier tube was constructed and used to power the photomultiplier tube and connect the photomultiplier tube’s output to a chart recorder/integrator. A horseradish peroxidase catalyst was immobilized by a polyacrylamide gel at the capillary window in order to detect the chemiluminescence intensity detection of 1mM luminol in a 0.1M borate buffer (pH 9) with H₂O₂.

Future Plans: Jon is currently working as a Quality Control Technician at ND Industries in Troy, MI.

Jennifer Hawk

Thesis Title: The Adsorption of Sulfur Containing Compounds by Transition Metal Oxides.

Thesis Abstract: The main goals of this project were two fold. The first area of investigation included the creation of a mixed metal oxide from ZnO and CaO of the form Zn_xCa_1-xO. Samples of ZnO and CaO were combined in desired ratios and baked. The resulting solid was then analyzed using XRD to determine if the mixed metal oxide had been successfully formed. Unfortunately the mixed metal oxide was not successfully created. It is thought that the different structures of ZnO and CaO (wurtzite and rock salt) were just not compatible. The second area of investigation was a specific reaction of a transition metal oxide (TMO) and a sulfur-containing compound. For this study, the reaction of CuO and H2SO4 was studied specifically. Variables that were studied included the either soaking or drying the CuO before the reaction was carried out, adding the H₂SO₄ by different means and by varying the soaking time of the CuO in the H2SO4 before filtering it. It was observed that the reaction is not just a simple acid base reaction but does depend somewhat on surface interactions and surface phenomena.

Future Plans: Jennifer is currently in the Ph.D. program in the Chemistry department at Duke University.

Zachary Kohley

Thesis Title: Experimental and Ab initio Study of the Adsorption of Liquid H₂O onto the ZnO, CuO, and FeO Surfaces.

Thesis Abstract: The adsorption reaction of H₂O onto the surfaces of ZnO, CuO, and a FeO/Fe₂O₃/Fe₃O₄ mix (Fe-mix) was examined using experimental and ab initio techniques. Gravimetric measurements and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) were used to study the interaction between liquid H₂O and the metal oxides. The filtering techniques allowed for comparative adsorption reactivities and desorption rates to be determined for the interaction between the metal oxides and deionized (DI) water. The results showed the adsorption reactivity trend to be Fe-mix ZnO CuO and the desorption rate trend to be ZnO Fe-mix = CuO. The DRIFT spectra of the adsorption of DI water onto dried CuO and ZnO surfaces provided information on the bonding structure of the systems. The results demonstrated that the ZnO dissociatively adsorbed the first aliquot of water and then molecularly adsorbed the following doses to the point of saturation. The CuO spectra showed that the adsorption of water onto the CuO surface was molecular and was dose independent. The ZnO, CuO, and FeO surfaces were all modeled using two atom clusters and larger extended clusters. The two atom cluster calculations showed the most favorable adsorption mechanism for all three metal oxide surfaces to be the dissociative adsorption of H⁺ and OH^- onto the oxygen and metal atoms, respectively. The adsorption energies of the two-atom systems were calculated and provided the following trend: ZnO FeO CuO. The larger clusters provided a better surface representation, which therefore provided insight into the most favorable surface sites for both molecular and dissociative adsorptions. Together, the experimental and ab initio results provide insight into the complex interaction between water and metal oxides.

Future Plans: Zach is currently in the Ph.D. program at the University of Texas A&M Cyclotron Institute.

Emily Miller

Thesis Title: Effect of Sample Load and Cyclodextrin Concentration on Enantiomeric Separations Using Capillary Electrophoresis.

Thesis Abstract: Enantiomeric separations of chlorpheniramine, warfarin, verapamil, ketoprofen, pindolol, and 5-(4-methylphenyl)-5-phenylhydantoin were performed using capillary electrophoresis with sulfated-â-cyclodextrin as a chiral additive. It was found that the greatest resolution and efficiency values are obtained when using a high concentration of cyclodextrin (30-60 mM cyclodextrin), a 25 ìm capillary over a 50 ìm capillary, and a low sample load of analyte (~0.1 mg/mL). When a high sample load is necessary for detecting enantiomeric impurity, better separation occurs with an increased injection time (i.e., 75 seconds compared to 10 seconds).

Future Plans: Emily is currently working at the Environmental Testing at Enviro Compliance in Portsmouth, VA.

Lauren Tignanelli

Thesis Title: Separation of Amino Acids Using High Performance Liquid Chromatography with Chemiluminescent Nitrogen-Specific Detection.

Thesis Abstract: The separation of 20 physiological amino acids using high performance liquid chromatography coupled with chemiluminescent nitrogen detection was studied in order to improve upon previously determined separation conditions. Through the adjustment of various parameters including mobile phase, stationary phase, ion-pairing agents, and others, the number of amino acids separated and overall separations were increased. At the end of the six weeks of research, 18 of the 20 amino acids had been separated. Further exploration into this can be done in order to further the separations and extend this research into other fields.

Future Plans: Lauren is currently in the Teacher Certification Program at Saginaw Valley State University.