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Chemistry Seminars

Chemistry Seminar
March 22, 2012
Room 113, Lathrop Hall 11:00 a.m.

Ms. Jenifer Shattuck

Insight into the Interactions that Play a Role in Amyloid Fibril Formation and Stability

Abstract: Amyloid fibrils are filamentous structures formed by many peptides or proteins with differing sequences but similar morphologies. These fibrils have sparked interest in the biomedical research field in the recent years because they have been found to arise in many diseases such as Type II diabetes, Huntington's disease, and Prion diseases. This seminar focuses on amyloid-ß peptide that is associated with Alzheimer's disease. The Ishii group in 2001 developed a new NMR technique, constant-time finite-pulse radiofrequency-driven recoupling (fpRFDR-CT) that is carried out under magic-angle spinning conditions. This new technique allows for characterization of the amyloid fibril structural order of certain segments of the peptide. The results obtained provide information about the structural constraints of the full length peptide that is used in molecular modeling programs to develop a structure of the amyloid-ß peptide. Thus the results reveal parallel ß-sheet alignment of neighboring peptide chains and this structural conformation has been named "cross-ß motif". In the application of these results, hydrophobic and electrostatic interactions between amino acid side chains will be discussed because they are crucial in the stabilization of the amyloid fibril that led to the senile plaques associated with Alzheimer's disease.

Mr. Patrick Cost

Design of High Efficiency Organic Solar Cells

Abstract: The world is currently in an energy crisis with depleting resources and rising costs of living. While looking for a change of energy source, in a green direction, solar cells were a topic of much interest. Solar cells are expensive to produce; however, a topic that is not as commonly known is organic solar cells (OSCs). Research has been completed in attempt to synthesize the most effective OSCs to aid in the current energy crisis. The topic being talked about is a specific set of dye sensitized solar cells, OSCs, which use a cobalt polypyridine mass transport systems consisting of Co[dmb]3+, Co[dpy]3+ and Co[dtb]3+, organic dyes with a great amount of steric bulk, and mesoporous TiO2 conduction bands. Generic dye sensitized cells include a ruthenium dye with the use of an iodine/triiondine redox pair but progress has been made to synthesize more efficient, and more eco-friendly complexes. The I/I3 redox couple with ruthenium dyes provide just under 11% efficiency, however, these numbers can potentially be surpassed with the use of cheaper, and greener materials. The main findings of this experiment was that organic dyes with a nitrogen center are sufficient electron donators which can opporate at an equivalent level as the ruthenium dyes; and cobalt mass transport systems are a legitimate redox mediators, which with proper modifications can far surpabbss traditional iodine mediators.