Granular solids consisting of various particle sizes exhibit the tendency to de-mix, or segregate, when caused to shear by external forces such as gravity. This well-known phenomenon is of special practical interest to many industries involved in the handling and transportation of bulk solids, where segregation can lead to adverse...
MoS2 is a ubiquitous catalyst for hydrogenation and hydrogenolysis reactions for hydrotreating of petroleum sources for the removal of sulfur and nitrogen containing compounds. Through exploration of this activity, structural models for MoS2 as a series of stacked S-Mo-S platelets held together by Van der Waals forces has been developed....
Growing concerns associated with global warming and the depletion of oil reserves have motivated significant research in support of sustainable polymers systems. In this thesis, biobased and biodegradable polymer blends and nanocomposites were created using a novel processing method, solid-state shear pulverization (SSSP). This process utilizes a modified twin-screw extruder...
The adoption of surfactant replacement therapy (SRT) for the treatment of neonatal respiratory distress syndrome (nRDS) is one of the main contributors to the dramatic decline in infant mortality rates observed in the 1980s. Despite the significant efficacy of animal-derived surfactant preparations, there are still some concerns associated with their...
To increase the butanol titers and selectivity in <em>Clostridium acetobutylicum</em> we replaced the promoter of the alcohol/aldehyde dehydrogenase (<em>aad</em>) gene with the phosphotranbutyrylase (<em>ptb</em>) promoter and combined this with CoAT downregulation to minimize acetone production. This led to early production of high alcohol (butanol plus ethanol) titers and overall solvent...
Granular materials exhibit a wide variety of fascinating physical properties that can be observed both in nature and industry. The goal of this work is to better understand the flow, mixing, and segregation of granular materials in a prototypical system, the rotating tumbler, using numerical modeling, specifically, the Discrete Element...
Nature has been evolving innovative solutions to complex design challenges for billions of years, the success of which is evidenced by the myriad of life-sustaining systems that operate with unparalleled simplicity, efficiency, and durability. Biomimetic researchers derive inspiration from principles underlying natural phenomena to solve design challenges. This work is...
T-cell activation is an essential step of the immune response, yet the cellular and molecular events underlying this complex process are not fully understood. Significantly, a comparative genome-scale transcriptional analysis of two T-cell subsets and the natural-mixed CD3+ population remains unexplored. Using microarrays, we investigated the temporal global transcriptional profile...
Improving cancer treatments are saving the lives of many young women, however these treatments often lead to premature infertility. The in vitro development of ovarian follicles would provide reproductive options to these women by supporting immature follicle growth following ovarian tissue cryobanking. In addition, the system provides a platform to...
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...
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...
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...
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...
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,...
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...
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...
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...
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....
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...
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...