Scientific Publications 2005
2005. "Development of Highly Active Pd-ZnO/Al2O3 Catalysts for Microscale Fuel Processor Applications." Chemical Engineering and Technology 28(4):515-519. Abstract A series of alumina supported Pd-ZnO catalysts were sythesized and studied for mthanol steam reforming. Pd loading and Pd/Zn ratio were optimized to improve catalyst activies. Among all the catalysts studied, the catalyst with a Pd loading of 8.9wt% and a Pd/Zn molar ratio of 0.38 exhibited highest methanol conversion lowest CO selectivity. The significantly improved Pd-ZnO/AI2O3 catalyst activity was one of the main factors that the efficiency of a micro-scaled fuel processor was improved from 9% to 15%.
2005. "A Complete Backbone Assignment of the Apolipoprotein E LDL Receptor Binding Domain [Letter to the Editor]." Journal of Biomolecular NMR 32(2):177. doi:10.1007/s10858-005-6729-2 Abstract Human apolipoprotein E (apoE) is a 299-residue exchangeable apolipoprotein that was initially recognized as a major determinant in lipoprotein metabolism and cardiovascular diseases. Recent evidence has indicated that apoE also plays critical roles in several other important biological processes not directly related to its lipid transport function, including Alzheimer’s disease, cognitive function, immunoregulation, cell signaling, and possibly even infectious diseases. ApoE contains two structural/functional domains: A N-terminal domain spanning residues 1-191 that is responsible for apoE’s LDL receptor binding activity and a C-terminal domain (residues 216-199) that is responsible for lipoprotein-binding (1). The x-ray crystal structure of the lipid-free apoE N-terminal domain was solved by Wilson et al in 1991 which represented the only high-resolution structure of this protein. This structure showed an unusually elongated (65 Å) four-helix bundle (2) that was organized in such 2 a way that its hydrophobic faces were directed towards the protein interior, whereas the hydrophilic faces were oriented towards the solvent. The major receptor-binding region, residues 130-150, was located on the fourth helix. The amphipathic a-helices were connected by short loops, giving rise to a compact, globular structure. However, this structure only contained residues 23-165. Recent studies have shown that residues beyond residues 23-165 are also very important to the apoE LDL receptorbinding activity. For example, a mutation at position R172 reduces the receptor binding activity of apoE to only ~2% (3). In addition, an E3K mutant significantly increased the apoE receptor binding activity as well (4). While the x-ray crystal structure of the apoE N-terminal domain provided detailed structural information for most region of this domain, this structure does not provide an explanation of the above experimental results regarding the structural contribution to apoE’s LDL receptor binding activity by these residues that are located in the region which is not seen in the x-ray crystal structure.
2005. "Small Pd Clusters, up to the Tetramer At Least, Are Highly Mobile on the MgO(100) Surface." Physical Review Letters 95(14):146103, 1-4. Abstract The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. Density functional theory calculations predict that small clusters of Pd atoms, containing up to at least four atoms, are highly mobile on the MgO(100) surface with the tetramer having the largest diffusion rate at room temperature—larger than the monomer. Surface vacancies are found, however, to bind the larger clusters strongly enough to trap them. These are important considerations when analyzing the growth and sintering of metal islands on oxide surfaces, in particular, the role of point defects.