Two subjects are the focus of this dissertation: Au/TiO2 catalyst used for oxidation of CO at low temperature and siloxane nanocages, a novel material (~2nm) recently developed in our group
While bulk gold is chemically inert, gold supported as nanoparticles is remarkably active for the oxidation of carbon monoxide at...
The task of designing porous materials for use in specific applications requires a detailed understanding of the adsorption process and how adsorption is affected by material properties. Applications of interest include maximizing gravimetric or volumetric adsorption capacity for hydrogen and carbon dioxide and increasing the selectivity for carbon dioxide in...
The recent tightening of permissible NOx release from diesel-powered engines has intensified the search for a catalytic system that can effectively remove NOx under challenging diesel exhaust conditions. Hydrogen-assisted selective catalytic reduction (H2-SCR) using supported palladium catalysts offers significant promise for lean NOx treatment due to its high activity at...
The prediction of multicomponent adsorption equilibria from pure component data alone has been an active research area for over forty years. The Ideal Adsorbed Solution theory (IAS) has been the standard method of doing so, but contains an embedded assumption of Langmuir mixing. This assumption causes its predictions to be...
Granular matter and living cells represent two extremes of what have come to be regarded as complex systems - systems characterized by a richness in global behavior that is not easily deduced from the interactions of their individual parts, even when those interactions are simple and well understood. On the...
Time-resolved in situ synchrotron x-ray scattering studies of particle orientation in polymer-clay nanocomposites under simple shear and complex flow were performed. Shear flow experiments used an annular cone and plate x-ray shear cell to allow measurement of platelet orientation within the flow-gradient plane.
Intercalated nanocomposites were made by dispersing organically...
Separation of DNA molecules by electrophoresis through entangled polymer solutions continues to be an important tool for genetic analysis, especially Sanger-based DNA sequencing. Separations of DNA on microfluidic devices are much more efficient than in capillary electrophoresis (CE) systems, such that the implementation of DNA sequencing onto microchips promises to...
The proper distribution of cellular organelles and protein complexes is important for maintaining cellular organization and function. Transport in eukaryotic cells requires three motor proteins, kinesin, dynein, and myosin, attached to specific cargoes mostly by adaptor proteins. This work focuses on the mechanism of microtubule-dependent organelle transport in vivo.
This...
The automobile coating industry is undergoing reformation driven by environmental regulations that demand low content of volatile organic compounds. Traditional solvent-borne acrylic resins
consisting of high molecular weight polymers that are produced at low temperatures (< 80 C) need high levels of organic solvent (70%) to be processed as coatings....
The average and local glass transition temperatures (Tgs) and physical aging behavior of various confined polymers were studied in order to gain an understanding of these surface/interface effects and their propagation into the polymer. Using a novel multilayer/fluorescence method, the Tgs of layers at the free surface, substrate-polymer interface, and...
The world's aquatic food webs are currently in crisis due to the cumulative, interacting effects of anthropogenic pressures including non-indigenous species invasions, chemical contamination, overfishing, habitat disruption and global climate change. Efforts to restore or protect the integrity and sustainability of these systems are limited by a lack of knowledge...
Natural tissues can have complex architectures characterized by the organization of multiple cells into structures, such as branching networks of the vascular or nervous systems. This cellular organization arises, in part, from spatial patterns in the expression of soluble factors, which create concentration gradients that direct cellular processes during morphogenesis....
Over the past decade and a half, there has been considerable interest in the effect confinement and interfaces have on the properties of glass forming materials. With the emergence of nanotechnology, some glass formers, in particular polymeric glass formers, will be used at increasingly smaller length scales. An understanding of...
The growing worldwide threat of antibiotic-resistant pathogens has necessitated a constant search for new classes of antibiotics. Antimicrobial peptides (AMPs) are integral components of innate immunity in virtually every living organism, and, due to their proven efficacy over millions of years of evolution, are considered promising leads for new antibiotic...
The de novo design of bio-inspired materials with precisely controlled properties is challenging, but has potential applications in nano-biotechnology. Applications range from nanometer scaled assemblies to three-dimensional scaffolds for tissue engineering. Genetic engineering of protein-based polymers offers distinct advantages over traditionally synthesized polymers, de novo proteins can be produced with...
Cells are regulated by a combination of soluble stimuli and adhesive interactions with other cells and the extracellular matrix (ECM). We are developing systems to present ECM and cytokine receptor ligands in a defined manner for applications in hematopoietic stem and progenitor cell (HSPC) culture. We hypothesize that the controlled,...
End-Labeled Free-Solution Electrophoresis, or ELFSE, is an alternative strategy for DNA sequencing that proposes to eliminate the need for a viscous sieving matrix for size-based DNA separation. In this bioconjugate method, a perturbing entity or "drag-tag" is attached to differently sized DNA fragments produced by the Sanger reaction. This drag-tag...
Resource recovery is a promising category of polymer recycling where polymeric waste is converted via thermal or chemical means to monomer and chemical feedstocks. Specifically, pyrolysis is an attractive method because of its simplicity and ability to handle a heterogeneous feedstock. Polymer pyrolysis is characterized by a complex free radical...
Tissue engineering offers a promising approach for the replacement of diseased or injured tissues, and is based upon the premise that cells can be induced to form new tissues when presented with the appropriate set of environmental cues. Polymer scaffolds play a central role in most tissue engineering strategies by...
The genetic information in DNA is transcribed to mRNA and then translated to proteins, which form the building blocks of life. Translation, or protein synthesis, is hence a central cellular process. Decades of experimentation have elucidated a vast wealth of molecular information about discrete translation steps, but the sheer complexity...