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Experimental Investigation Of Clay Aggregate And Granular Biofilm Behavior, Tao Jiang
Experimental Investigation Of Clay Aggregate And Granular Biofilm Behavior, Tao Jiang
Doctoral Dissertations
Clay minerals are a class of phyllosilicates as the major solid constituents in cohesive fine-grained soils (e.g., clays). Owing to their tiny size (i.e., < 2 μm), high aspect ratio, and active surface properties that inherit from the geological process, clay minerals can extensively interact with other suspended matter (e.g., exoployemers, microorganisms) and dissolved ions via the process of flocculation and aggregation, resulting in the formation of larger, porous cohesive particulate aggregates or flocs. Such a complex mechanism of microscale particle interaction generates significant challenges for understanding the bulk clay behavior as a particulate system. In order to better characterize the flocculation and aggregation of clay minerals under various stimuli and to understand the underlying mechanism of particle interactions, particle/aggregate size kinetics of flocculated suspensions of illite, a representative 2:1 clay mineral abundant in marine soils, are studied with varied ionic strength induced by monovalent salt (NaCl), pH, and hydrodynamic shearing in the first phase of this research. Furthermore, a new statistical data binning method termed “bin size index” (BSI) was employed to determine the probability density function (PDF) distributions of flocculated illite suspensions. The statistical results demonstrate that the size kinetics of flocculated illite suspensions is chiefly controlled by the face-to-face and edge-to-face interparticle interactions under the mutual effects of ionic strength and pH, while the hydrodynamic shearing has minimal effects on the variation of particle size groups. In the second phase of this research, the mechanics of clay aggregates are studied using an innovative measurement technique and analytical approach. Individual clay minerals prepared with different mineralogy and salinities are tested via unconfined compression, which shows that the increasing ionic strength can improve the strength and stiffness of clay aggregates, which are further affected by the mineralogical compositions and dominant microfabric in different water chemistry. In the final phase of this research, a collaborative study with an environmental engineer on an NSF CAREER project was conducted to investigate the mechanical behavior of macroscale, light-induced oxygenic granules (biofilm aggregates) using the same technique and analytics developed for the individual clay aggregates. The findings are expected to provide reference values to subsequent studies and engineering practices associated with the water treatment process.
Small Heat Shock Protein 27 And Its Role In Human Disease, Bianka Andrea Holguin
Small Heat Shock Protein 27 And Its Role In Human Disease, Bianka Andrea Holguin
Open Access Theses & Dissertations
Small heat shock protein 27 (Hsp27) is a ubiquitously expressed molecular chaperone with roles in many physiological processes. As an ATP-independent molecular chaperone, Hsp27 protects substrates from irreversible aggregation and holds them in a folding competent state for later recycling into the proteome. Hsp27 proteins form dimers that are assembled into large oligomeric complexes. Phosphorylation of Hsp27 dissembles the oligomers into chaperone active dimers. Several missense mutations of Hsp27 are causative for the neurodegenerative disorders Charcot-Marie-Tooth disease 2F and distal Hereditary Motor Neuropathy IIB. Here I show that the oligomerization and chaperoning ability of Hsp27 are altered by the Hsp27 …
Optimizing Virus Prefiltration For Biopharmaceutical Manufacturing, Solomon Isu
Optimizing Virus Prefiltration For Biopharmaceutical Manufacturing, Solomon Isu
Graduate Theses and Dissertations
Virus filters are single-use devices that use a size-based separation process. In virus filters, contaminating virus particles are retained while the therapeutic molecules pass through the membrane pores. Virus filters are an essential component of the overall virus clearance strategy. Sections 1 and 2 of this dissertation provide an introduction and extensive review of monoclonal antibody (mAb) process development, where virus filtration is pivotal. In section 3, prefiltration studies were performed with an industrially relevant IgG1 type mAb using adsorptive and size-exclusion-based prefilters with different mechanisms of action. This mAb has an isoelectric point range of 7.1 to 8.0 and …
The Importance Of Protein Context In Spinocerebellar Ataxia Type 3, Sean Luis Johnson
The Importance Of Protein Context In Spinocerebellar Ataxia Type 3, Sean Luis Johnson
Wayne State University Dissertations
Spinocerebellar Ataxia Type 3 (SCA3) is a member of the family of polyglutamine (polyQ) neurodegenerative disorders that includes Huntington's Disease and several other SCAs. SCA3, the most common dominant ataxia in the world, is caused by polyQ tract expansion in the protein, ataxin-3. How SCA3 occurs and how to treat it remain unresolved issues. The primary culprit of toxicity in all polyQ diseases is the glutamine repeat: its abnormal expansion leads to neuronal dysfunction and death. With that said, there is indisputable evidence that the way polyQ-dependent toxicity presents—areas impacted, cellular processes perturbed—is predicated in large part on regions outside …