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Ion transport of electrolytes determines the performance of many electroactive devices, from fuel cells to batteries to soft mechanical actuators. This dissertation aims to address some fundamental issues regarding ion transport of ion dense electrolytes using electrophoretic NMR and NMR diffusometry. I first describe the design and fabrication of the first instrumentation capable of reliable ENMR on highly ion-dense electrolytes such as ionic liquids and electrolytes for zinc-air batteries. I design a new electrophoretic NMR sample cell using parallel capillaries to investigate the electrophoretic mobilities of pure ionic liquids. It shows the first study of a highly ion-dense electrolyte with electrophoretic NMR. Then I employ NMR diffusometry and electrophoretic NMR to investigate ion association of pure ionic liquids. Then I use electrophoretic NMR technique to investigate the electrophoretic mobilities of electrolytes for zinc-air batteries. For Zn2+ salt added dicyanamide (dca) based ionic liquids, I investigate the effects of Zn2+ salt on chemical shift of dca and ion motion. The combination of mobilities measurements and diffusion measurements provides some new insight of ion aggregation. We explore ion transport of ionic liquids inside the ionic polymer Nafion as a function of hydration level. When ionic liquids diffuse inside ionic polymers, isolated anions diffuse faster (e 4X) than cations at high hydration whereas ion associations result in substantially faster cation diffusion (d 3X) at low hydration inside membranes, revealing prevalent anionic aggregates. Finally, we compare diffusion activation energy measurements in a hydrated perfluorosulfonate ionomer and aqueous solutions of triflic acid, which provides insight into water transport dynamics on sub-nm lengthscales. And we explore the physical meaning of activation energy, characterizing local intermolecular interactions that occur on the pre-diffusional (~ 1 ps) timescale. / Ph. D.

Within this study, the focus will be on oligoglycines. Numerous studies pertaining to the mobility and conformations of oligoglycines have been completed, as this is a driving force for the study. The oligopeptide is modeled using a “coarse-grained” model created in the Allison lab at Georgia State University [Xin,Y.,et. al, J. Phys. Chem. B 2006, 110, 1038-1045], which will be briefly explained within this paper. Oligoglycines will be studied in a few different systems, as the overall charge on the peptide and system will affect its mobility. The conclusion drawn is that the peptide adopts three different conformations based on the temperature of the system and length of the peptide; random conformation at high temperatures, and compact conformations at low temperature. Oligoglycines of length three to five amino acids adopts a cyclic conformation at low temperatures. [Allison, S., et al., J. Sep. Sci. 2010, 33, 2430- 2438.]

O estudo da dispersão e estabilização de barbotinas de porcelana de cinza de ossos é uma etapa muito importante no processo de conformação de peças cerâmicas, assim como também a etapa de obtenção da sua principal matéria-prima que é a cinza de ossos, devido a que constitui 50% em peso da porcelana e por ser uma matéria-prima renovável, reciclável e com alto valor agregado na fabricação de porcelana. Neste trabalho se investigou a influência das temperaturas de calcinação dos ossos (700, 800, 900 e 1000 °C) moídos e lavados, no seu tamanho, forma das partículas, composição química, comportamento elétrico superficial das partículas com o meio líquido, grupos funcionais e possíveis contaminantes nas superfícies das partículas dos ossos calcinados, que poderiam prejudicar a preparação de barbotinas de porcelana de ossos. Mostra-se também a dispersão, preparação e a estabilização da mistura de porcelana de ossos (50% cinza de ossos, 25% de caulim, 25% de feldspato) por meio dos ensaios de viscosidade e mobilidade eletroforética, conseguindo dispersar, homogeneizar e estabilizar as suspensões de porcelana de ossos aplicando tempos de envelhecimentos apropriados. / The study of the dispersion and stabilization of slip casting of bone porcelain is a very important stage in the process of preparation of suspensions ceramic, as well as the obtaining of its main material, that it is the bone ash, so that it constitutes 50% in weight of dry mass, and also that is one raw material renewable, recyclable and with high value added in the porcelain production. In the present research, the influence from the calcination of bovine bones to different temperatures (700, 800, 900 and 1000 °C) was investigated besides the size and form of the particles, variation in its chemical compositions, variations in its electric superficial behavior of the particles in contact with the liquid medium and also the groups present functional in the particles of ash of bones, kaolin and feldspar. Reveals the behavior of the particles during the dispersion and stabilization of the bone porcelain (50% ash of bones, 25% kaolin, 25 % feldspar) by means of the tests of viscosity and electrophoretic mobility, being able to disperse, to homogenize and to stabilize the suspensions of bone china with appropriate ageing time.

O estudo da dispersão e estabilização de barbotinas de porcelana de cinza de ossos é uma etapa muito importante no processo de conformação de peças cerâmicas, assim como também a etapa de obtenção da sua principal matéria-prima que é a cinza de ossos, devido a que constitui 50% em peso da porcelana e por ser uma matéria-prima renovável, reciclável e com alto valor agregado na fabricação de porcelana. Neste trabalho se investigou a influência das temperaturas de calcinação dos ossos (700, 800, 900 e 1000 °C) moídos e lavados, no seu tamanho, forma das partículas, composição química, comportamento elétrico superficial das partículas com o meio líquido, grupos funcionais e possíveis contaminantes nas superfícies das partículas dos ossos calcinados, que poderiam prejudicar a preparação de barbotinas de porcelana de ossos. Mostra-se também a dispersão, preparação e a estabilização da mistura de porcelana de ossos (50% cinza de ossos, 25% de caulim, 25% de feldspato) por meio dos ensaios de viscosidade e mobilidade eletroforética, conseguindo dispersar, homogeneizar e estabilizar as suspensões de porcelana de ossos aplicando tempos de envelhecimentos apropriados. / The study of the dispersion and stabilization of slip casting of bone porcelain is a very important stage in the process of preparation of suspensions ceramic, as well as the obtaining of its main material, that it is the bone ash, so that it constitutes 50% in weight of dry mass, and also that is one raw material renewable, recyclable and with high value added in the porcelain production. In the present research, the influence from the calcination of bovine bones to different temperatures (700, 800, 900 and 1000 °C) was investigated besides the size and form of the particles, variation in its chemical compositions, variations in its electric superficial behavior of the particles in contact with the liquid medium and also the groups present functional in the particles of ash of bones, kaolin and feldspar. Reveals the behavior of the particles during the dispersion and stabilization of the bone porcelain (50% ash of bones, 25% kaolin, 25 % feldspar) by means of the tests of viscosity and electrophoretic mobility, being able to disperse, to homogenize and to stabilize the suspensions of bone china with appropriate ageing time.

The U.S. Environmental Protection Agency is in the process of developing a nationwide standard for turbidity in construction site runoff. It is widely expected that this standard cannot be met with conventional erosion and sediment control measures; consequently, innovative practices for managing sediment on construction sites must be developed. The objective of this research was to develop an understanding of how soil characteristics and polymer properties affect the amount of turbidity reduction that can be achieved through flocculation. The polymers used were PAMs, a proprietary product, and chitosan. The charge density of the PAMs ranged from 0% to 50% and the molecular weights ranged from 0.2 to 14 Mg/mol. A protocol for creating modified synthetic stormwater runoff for soil samples was developed and used on soils from seven construction sites. Particle size distributions were used to compare the modified synthetic stormwater runoff with grab samples of stormwater from one site and showed the synthetic runoff was representative of the actual runoff. Flocculation tests were performed on the synthetic runoffs with PAM and chitosan doses from 0.03 to 10 mg/L. The non-ionic PAM, proprietary product, and chitosan were found to be the most effective at reducing the turbidity of all the synthetic runoff below 200 NTU. The high molecular weight anionic PAMs were effective on only two of the seven synthetic runoff samples. Hardness tests were performed indicating interparticle bridging to be the bonding mechanism of the PAM. Electrophoretic mobility tests were performed on two of the soil suspensions and indicated the bonding mechanism of PAM to be interparticle bridging, and the bonding mechanism of chitosan to be a combination of charge neutralization and interparticle bridging. Tests showed as the charge density of the PAM increased, their effectiveness decreased. / text

Chlamydia is a clinically significant organism that exhibits a unique stage-specific developmental cycle, involving the interconversion between two metabolically distinct forms. The completion of eight chlamydial genome sequences identified three different RNA polymerase sigma factor (ó) genes. Temporal gene expression analysis has predicted that each ó may play an integral role in controlling the development cycle. This thesis examines the role of the chlamydial alternate sigma factor, ó54 (rpoN) and the potential mechanism for the control the developmental cycle and disease pathogenesis. To achieve this, we searched the genome for putative ó54 promoters, validated the findings by DNA-binding assays, and examined the roles of the genes predicted to be regulated by ó54. This study applied a bioinformatics approach to search for additional ó54 regulated genes in C. trachomatis L2. A reduced consensus sequence (TGGCACnnnnnTTGC) identified two previously published ó54 promoter sequences upstream of CT652.1 and CT683. A modified consensus sequence (TGG-N9-TGC) was applied to the C. trachomatis D genome in Findpatterns yielded 512 potential targets of which 20 by virtue of sequence orientation and distance upstream of the predicted ORF start codon Primer extension analysis of total RNA isolated at 24 hours post-infection mapped the 5' RNA end upstream for acpS (CT100), yhf0_1 (CT258), SAM (CT404), lpxA (CT531), hypothetical proteins CT652.1 and CT683, and htrA (CT823) to the predicted ó54 promoters. Three candidates (CT291, CT404, and CT847) were mapped to putative ó70-like ó66 promoters. No transcript start sites were detected for the remaining ó54 promoter candidates. Two transcripts were detected from predicted ó66 and ó54 tandem promoters upstream of CT404. Primer extension analysis of the CT404 transcripts from RNA isolated at 4, 8, 12, 24 and 32 hours post-infection showed a decrease between 12 hours and 24 hours post-infection in transcripts thought to be generated from the predicted ó66 promoter. Transcripts from the predicted ó54 promoter were identified throughout development. Temporal gene expression profiles of the candidate genes with predicted ó54 promoters (CT652.1, CT683, CT100, CT258, CT531 and CT823) were resolved throughout the C. trachomatis L2 developmental cycle using real-time PCR. Transcripts for CT608 and CT609 were detected early in the cycle, while strong transcript levels were detected for CT258, CT531 and CT823 after the appearance of CT609 (rpoN). Low levels of CT652.1 and CT683 were measured, in the mid to late phase of the cycle, and transcripts for CT100 appeared at lower levels during the middle phase of the cycle. The functional assay of the predicted ó54 promoters required the generation of recombinant C. trachomatis L2 ó54 (rRpoN). The C. trachomatis rpoN was cloned into a bacterial expression system (pQE70) and the recombinant proteins purified for subsequent DNA mobility shift assays. Expression of rRpoN was hampered by low copy numbers, and unusual physical characteristics. DNA binding and mobility shift assays using rRpoN extracts against the chlamydial CT652.1 ó54 promoter, plus two characterised E. coli ó54 promoters (hypA and hycA), were successful if E. coli core RNA polymerase was added to the assay. All 20 candidates with predicted ó54 promoters were analysed with EMSA using rRpoN extract. The promoters upstream of CT100, CT223, CT258, CT322, CT652.1 and CT683 showed affinity towards the recombinant rRpoN-E. coli core RNA polymerase holoenzyme complex. Searches for potential chlamydial ó54 transcription initiation activators were made using the Multiple Em for Motif Elucidation (MEME) software, looking to identify the DNA binding motifs. The upstream promoter regions of CT100, CT223, CT258, CT322, CT531, CT652.1, CT683 and CT823 in C. trachomatis L2 and orthologs found in other species of Chlamydia were analysed. The software identified a near palindromic sequence upstream of CT100 orthologs in C. trachomatis D and C. trachomatis MoPn (CAACCCAAC and CACCACAAC) where as a CT531- and CT823-specific motif was also discovered (CCGTTGTAGAATCTC). It is beginning to emerge that ó54 may regulate the expression of proteins required for the formation of the cell wall. Since the expression of the ó54 transcript, rpoN, coincides with the morphological change from the non-infectious RB to the infectious EB, predictions could be made concerning which genes are potentially regulated by ó54.

The discovery that negatively charged aggregates of C60 fullerene are stable in aqueous environments has elicited concerns regarding the potential environmental and health effects of these aggregates. Although many previous studies have used aggregates synthesized using intermediate organic solvents, this work primarily employed an aggregate production method that more closely emulates the fate of C60 upon accidental release into the environment — extended mixing in water. The aggregates formed via this method (aqu/nC60) differ from those produced using the more common solvent exchange methods. The aqu/nC60 aggregates are heterogeneous in size (20 nm and larger) and shape (angular to round), negatively charged, and crystalline in structure — exhibiting a face centered cubic (fcc) system. Solution characteristics such as aqu/nC60 aggregate size and concentration were found to be dependant upon preparation variables such as stirring time, initial C60 concentration, and initial particle size. Additional experiments indicate that aggregate charge, structure, and stability are highly dependant upon the identity of co-solutes (NaCl, CaCl2, sodium citrate) and their concentrations. Citrate concentrations greater than 0.5 mM resulted in the formation of very small (< 20 nm) spherical aqu/nC60 particles. At moderate citrate concentrations (~ 1 mM) a more negative surface charge was observed, which may be an indication of increased nC60 stability. In contrast, high concentrations of monovalent and divalent electrolytes result in aggregation and sedimentation of nC60 out of solution. Our research describes the effect that solution composition has on aggregate formation and stability, and suggests that C60 fate and transport will be a function of solution composition. / Master of Science

>Magister Scientiae - MSc / Tuberculosis (TB) is a global health problem and rated as the second leading cause of death after HIV/AIDS. Transmission of TB from one person to the next is very rapid in crowded communities. Therefore, it is crucial to identify people who are infected as quickly as possible not only to provide treatment but also to prevent the spread of the disease. Current TB diagnostic tests such as the culture and sputum smear tests are time-consuming, while rapid tests make use of antibodies that are costly and have low sensitivity and stability. Great improvement has been observed when aptamers are used in place of antibodies in rapid diagnostic tests such as lateral flow devices (LFDs). Therefore, the current study aims to synthesize and identify aptamers against serum biomarkers for development of rapid TB diagnostic tests such as a lateral flow assay. Several TB serum biomarkers have been identified and can be used for the diagnosis of TB. TB biomarkers expressed in serum samples were identified through in silico approach. The biomarkers were expressed in bacterial systems using recombinant DNA technology. The recombinant proteins were purified by affinity chromatography and further used as targets for the selection of aptamers using Systemic Evolution of Ligands by EXponential enrichment (SELEX). Aptamers for the selected biomarkers were synthesized based on magnetic-bead based SELEX and characterized by electrophoretic mobility shift assay (EMSA), Surface Plasmon resonance (SPR) and MicroScale Thermophoresis (MST). Six putative TB serum biomarker proteins were selected from literature, namely, Insulin-like Growth Factor Binding Protein 6 (IGFBP6), Interferon-stimulated Gene 15 (ISG15), Calcium Binding Protein (S100A9), Retinol Binding Protein 4 (RBP4), Granzyme A (GrA), and Transgelin-2 (TAGLN2). The biomarkers were recombinantly expressed and purified after which they were used as targets in SELEX for aptamers synthesis. Aptamers were analysed by in silico method and the ones with highly conserved motifs were selected. The selected aptamers were synthesized and later characterized. The aptamers that show high affinity and specificity for the biomarkers will be used for the fabrication of a rapid lateral flow device for TB screening. Such a test would allow for a short diagnostic turnaround time, and hence expedite treatment.

Sodium saturated Utah bentonite was equilibrated in several concentrations of various sodium salt solutions. The effect of anions on the amount of sodium adsorbed was determined. The effect of anions on the electrophoretic mobility of the clay Has also studied. The results are reported herein.