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 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...
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...
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...
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...
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...
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 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...
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...
Using a novel DNA-microarray hybridization protocol, the diffusion distance during static microarray hybridization was estimated for Cy3- and Cy5-labeled cDNA probes as 3.8 and 2.6 mm, respectively, despite having almost identical molecular masses. Continuous mixing during microarray hybridization resulted in a 15-20% increase in signal intensity over arrays hybridized statically....
The hematopoietic stem cell (HSC) niche is the site where HSCs reside in vivo. The HSC niche is formed by supporting cells that provide structure and appropriate environmental cues for HSCs. In this study, three components of the HSC niche were evaluated for their influence on HSC expansion ex vivo:...
The physics of granular materials is one of the big questions in science. Granular materials serve as a prototype of collective systems far from equilibrium and fundamental questions remain. At the same time, an understanding of granular materials has tremendous practical importance. Among practical problems, granular mixing and its interplay...
Megakaryocytic cells (Mks) are derived from hematopoietic stem cells (HSCs) and give rise to platelets. Ex vivo culture of HSCs under conditions that promote Mk differentiation has been proposed as a method for producing Mks and platelets for cell therapies. Mk maturation involves the development of polyploid cells via endomitosis,...
Little is known about the transcriptional events underlying megakaryocytic (Mk) differentiation from hematopoietic stem cells. We sought to identify genes and pathways not previously associated with megakaryopoiesis and to evaluate the CHRF-288-11 (CHRF) megakaryoblastic cell line as a model system for investigating megakaryopoiesis.
Using DNA microarrays, Q-RT-PCR, and protein-level assays,...
Structural dynamics in three polymer blend systems, differing largely with respect to morphology, have been investigated. The first system, composed of two immiscible homopolymers, exhibits a microstructure of micron-sized droplets dispersed in a matrix phase. We have examined small-angle x-ray scattering (SAXS) as a new approach for conducting in situ...
Nature often uses reaction-diffusion(RD) as a means of making structures and materials of unique properties or morphologies on scales from macro- (e.g., stripes in zebras, tigers, and seashells, and formations in trees, agates, and rocks) to microscopic (e.g., cellular growth, chemotaxis and biological waves). However, reaction-diffusion phenomena have not yet...
The emergence of antimicrobial resistance and the growing concern to produce new drugs have influenced an increase in the amount of research directed towards the engineering of novel polyketides. The polyketide carbon backbone is synthesized by a set of enzymes known as polyketide synthases (PKSs). These catalyze the formation of...
The study of granular matter is both scientifically intriguing and industrially important, yet it presents several unique characteristics and challenges. The discrete nature of granular materials often precludes the use of the continuum descriptions that are so commonly used for fluids, so alternative methods must be developed. Particles interact via...
Spontaneous regeneration in the adult mammalian central nervous system is rare, minimal, and generally does not lead to substantial functional recovery. Tissue engineering strategies to promote nerve regeneration aim to provide an environment that is physically and chemically engineered to enhance tissue formation. Strategic design of this environment is crucial...
The use of processes based on microorganisms to produce fuels, monomers, and pharmaceuticals from renewable feedstocks is increasing today due to their environmental and economic advantages over petrochemical-based processes. In order to unlock the full potential of microorganisms to produce a sustainable industry centered on biosynthesis, an improved understanding of...