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Full-Text Articles in Engineering
Structural Dynamics And Encapsulation Properties Of Polyelectrolyte Complex Micelles, Sachit Shah
Structural Dynamics And Encapsulation Properties Of Polyelectrolyte Complex Micelles, Sachit Shah
Electronic Theses and Dissertations, 2020-
Charged therapeutics such as nucleic acids and proteins can treat a vast range of human diseases that are traditionally undruggable. Their broadness in treating disease is due to their ability to influence cellular function. However, their high charge density and physiological barriers such as enzymatic degradation, hinder the deliverability of these molecules to the sites of disease. Polyelectrolyte complex (PEC) micelles are core-corona nanostructures that can encapsulate charged molecules and offer a platform for delivery. PECs form the core, when two oppositely charged polyelectrolytes are mixed in an aqueous solution, and the micelle corona is a neutral hydrophilic polymer that …
Using Peptide Design To Engineer Polyelectrolyte Complex Biomaterials, Sara Tabandeh
Using Peptide Design To Engineer Polyelectrolyte Complex Biomaterials, Sara Tabandeh
Electronic Theses and Dissertations, 2020-
The self-assembly of oppositely charged polymers provides a versatile platform to design materials for diverse applications in biology and medicine. Electrostatically-driven phase separation of oppositely charged polymers in aqueous solution gives rise to the formation of a polymer-rich phase called a polyelectrolyte complex (PEC). PECs can be in the form of liquid droplets (complex coacervates) or amorphous solid precipitates. Unlike synthetic polymers, peptides are good candidates for developing tailor-made formulations and structure-property relationships due to their biocompatibility, precise control over sequences, and ability to program hydrogen bonding interactions. However, little is known about the effect of combining additional molecular interactions …
Surface Engineering Of Cerium Oxide Nanocyrstal Dispersions: Colloidal Properties, Ageing Effects, & Electroanalysis, Craig Neal
Electronic Theses and Dissertations, 2020-
Colloidal materials are highly diverse and present complex physicochemical properties which define their utilities in applications spanning diverse industries. In particular, nano-scale colloids have received tremendous attention due to their unique, specific activities as compared to larger-sized preparations. Within the biomedical sciences, nano-colloids are routinely used as inert carriers of therapeutics and/or diagnostic agents. Beyond this, researchers have developed functional colloids which demonstrate bio-active or diagnostic properties themselves: often related to an optimized, or tuned, surface character. Among these, nanoscale cerium oxide (nanoceria) has shown great promise as a bi-functional, therapeutic material: producing pro- or anti- oxidative chemical response in …
Processing Of 3d Porous Biomaterial Scaffolds To Enhance The In Vitro Breast Cancer Tumor Microenvironment, Zi Wang
Electronic Theses and Dissertations, 2020-
Tumors contain heterogeneous cell populations within the tumor microenvironment (TME). TME supports tumor progression and development via the function of multiple cell types and cell-extracellular matrix (ECM) interactions. 3D porous biomaterial scaffolds can be a type of in vitro tumor models to mimic TME ECM. Current tumor models lack structural complexity replicating tumor ECM, tunable mechanical properties, and have limited mass exchange between cells and their microenvironment. In this work, we firstly developed scaffolds with a hierarchical pore structure via the Freeze-FRESH(FF) fabrication technique that combines 3D printing and freeze-casting. Later, we studied the effect of varying processing parameters and …
Actin Cytoskeleton Dynamics And Organization Modulated By Macromolecular Crowding, Cation Interaction, And Nanomaterials, Jinho Park
Electronic Theses and Dissertations, 2020-
The assembly of actin, the essential cytoskeleton protein, into filaments and bundles/networks is important in various cellular processes including cell movement and morphogenesis. Actin bundle formation occurs in crowded intracellular environments with the aid of actin-crosslinking proteins. The role of actin-crosslinking proteins such as fascin and a-actinin in bundle formation has been investigated, however, how intracellular environments affect actin crosslinker-induced bundle formation is unknown. In the first two parts of this dissertation, we explore the effects of macromolecular crowding and cation interactions on the organization and mechanics of actin crosslinker-induced bundles. To determine how changing environmental conditions modulate actin bundling, …
Uv-Ozone Oxide Treatments For High-Efficiency Silicon Photovoltaic Devices, Munan Gao
Uv-Ozone Oxide Treatments For High-Efficiency Silicon Photovoltaic Devices, Munan Gao
Electronic Theses and Dissertations, 2020-
Fabrication of solar cells with higher efficiency, simpler processes and lower cost is largely perceived as the ultimate goal for photovoltaic research. To reach such a goal each step needs to be refined and optimized. In this dissertation, a UV-ozone treatment is proposed as a simple and versatile process that can be applied to multiple fabrication steps for improvement. The UV-ozone cleaning method provides comparable surface cleaning quality to more expensive and hazardous industrial standard RCA clean with less chemical used. A good passivation quality was achieved on both n-type and p-type silicon wafer by a silicon oxide/aluminum oxide passivation …
Microstructural Development Of Inconel 625 Nickel-Based Superalloy As Function Of Laser Powder Bed Fusion Parameters, Sofia Nucci
Microstructural Development Of Inconel 625 Nickel-Based Superalloy As Function Of Laser Powder Bed Fusion Parameters, Sofia Nucci
Electronic Theses and Dissertations, 2020-
Additive manufacturing (AM) allows fabrication of complex components with features that are impractical or impossible to achieve through conventional methods. Selective laser melting (SLM) powder bed fusion AM technology was selected for this study on Inconel 625, a widely utilized high-temperature alloy that is hard to machine. The present work investigates impact of laser power and scanning speed variations on the resulting characteristics of fabricated IN625 samples. Gas atomized metallic alloy powders were acquired and analyzed through laser diffraction to verify acceptable size distribution. Cubic samples were built with a range of laser scan speeds in 200 mm/s intervals for …
Solidification Cracking In Binary Al-Cu Alloys Additively Manufactured Through Laser Powder Bed Fusion, Keegan Muller
Solidification Cracking In Binary Al-Cu Alloys Additively Manufactured Through Laser Powder Bed Fusion, Keegan Muller
Electronic Theses and Dissertations, 2020-
Laser Powder Bed Fusion (LPBF) is an additive manufacturing technique with growing relevance in industry. However, alloys with a high susceptibility to micro-cracking during solidification cannot be feasibly manufactured through LPBF, such as in selected high-strength Al-alloys. The cracking susceptibility (CS) of Al-alloys varies with composition, so modeling CS with respect to composition is crucial in designing compatible alloys for LPBF. In a theoretical modeling of solidification cracking based on the Scheil equation, the relative CS is taken as the maximum value of |dT/d(fs^1/2)| when solidification is near completion. However, experimental observations of the crack density in Al-alloys suggest that …
Atomic-Scale Simulation Of Dissipation And Adhesion During Interactions Between Mineral Surfaces, Baochi Doan
Atomic-Scale Simulation Of Dissipation And Adhesion During Interactions Between Mineral Surfaces, Baochi Doan
Electronic Theses and Dissertations, 2020-
Adhesion and dissipation during surface interactions are important phenomena with wide applications in materials science, including cold-spray technology for additive manufacturing and stiction in MEMS (Mircro ElectroMechanical Systems). In planet formation theories, energy dissipation in collisions between mineral grains is important to the formation of dust-grain aggregates and planetesimals. Early contact mechanics theories such as Hertz and Johnson-Kendall-Roberts have laid theoretical foundations for understanding these phenomena. Recently, there are breakthroughs in using non-equilibrium thermodynamics methods to elucidate dissipation. For example, the Green-Kubo method can calculate transport coefficients based on the Fluctuation-Dissipation theorem, and Jarzynski equality can be used to determine …