ATRC PROCESSES AND ARCHITECTURES AS TOOLS FOR ADVANCING THE COMPLEXITY OF SINGLE-CHAIN POLYMERIC NANOPARTICLES

Atom transfer radical coupling (ATRC) is gaining recognition for its utility in building complex polymeric architectures because it features efficiency, a wide range of compatible substrates, and a lack of byproducts. These qualities are especially desirable in applications requiring intramolecular cross-linking as in the synthesis single-chain nanoparticles (SCNP). This dissertation aims to (I) provide motivation and context for developing ATRC technology for intramolecular cross-linking, (II) provide guidance into the impact of catalyst selection and substrate on reaction efficiency and morphology, and (III) demonstrate the possibility to sequence intrachain ATRC with ATRP to create advanced SCNP architectures. Chapter II describes the preparation of SCNP from parent polymers containing alkyl or benzyl bromide ester pendants using ATRC catalyzed by copper halides complexes. Tri- or tetradentate alkyl or pyridyl amines (PMDETA, TPEN, and TPMA), which tune the redox potential of the Cu(I)/Cu(II) system, were directly compared. Coupling efficiency was positively correlated with the kATRP of the respective catalyst systems. However, PMDETA complexes afforded greater control as evidenced by lower polydispersity. In the case of alkyl halide pendants, selectivity for coupling over disproportionation systematically decreased under conditions designed to increase the concentration of CuI/L. Polymers with benzyl bromide pendants, which cannot disproportionate, tended to produce high molecular weight products, even in ultradilute solutions (0.25 –1.0 mg/mL). Chapter III describes the preparation of SCNP from parent polymers capable of initiating intra-chain polymerization by ATRP under conditions favoring termination by coupling. Because of the wide variety of compatible monomers that have been well-established for ATRP systems, the ATRP/C framework both simplifies reaction procedures (one pot polymerization and coupling strategies are feasible) and imparts handles with which to control both architecture and functionality. To demonstrate this potential, model simple brushes and hyperbranched examples were prepared. SCNP with the hyperbranched motif were remarkably dense, a result which demonstrates the potential to facilitate more globular SCNP structures using modifications of intrachain polymerizations. Methacrylic brush arms, which are not non-ATRC active, could be induced to couple by adding 5 equivalents of styrene under the shared ATRP/C conditions. In addition, it was determined that hyperbranched SCNP retain “living” ω-ends which may be initiated to perform post-collapse polymerizations. A model styrene example is presented; despite occurring in an ultradilute solution, the polymerization maintains fidelity to pseudo-first order kinetics. In sum, there is currently a great impetus for pushing the boundaries of structural and functional complexity that can be designed using the single-chain nanoparticle motif. Atom transfer radical chemistry is a particularly versatile example and it is my hope that this work facilitates the creation of new creative and functional designs

Adsorptive Removal of Iron and Manganese from Groundwater Samples in Ghana by Zeolite Y Synthesized from Bauxite and Kaolin

Ground water samples from residential homes in three Regions of Ghana: Central, Greater Accra and Ashanti, were analyzed for iron and manganese contamination. The samples were exposed to characterized zeolite Y by X-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transformed-infrared spectroscopy and thermos gravimetric-differential thermal analysis. Zeolite Y is able to remove 98% of iron and 97% of manganese within an hour. The adsorption of both iron and manganese follows the Freundlich model, whilst the kinetic studies show that pseudo-first order and intra particle and film diffusion models provided the best fit, suggesting the transport of the ions onto the zeolite Y surface and the subsequent diffusion into the zeolite Y framework. The adsorption at 0.2 mg L−1 Fe (0.2) is calculated to be 0.023 mg g−1 for the Freundlich adsorption model, whilst that of manganese at 0.05 mg L−1 Mn (0.05) is evaluated to be 0.015 mg g−1. The zeolite retains its adsorption properties when retrieved from the first exposure water sample, washed copiously with distilled water and added to fresh water samples. The results suggest that zeolite Y can be used as a potential adsorbent for the removal of iron and manganese from groundwater.Third World Academy of Sciences (TWAS) (Grant # 16-471 RG/PHYS/AF/AC_G), Grand Challenges Canada (Grant # RS-0148 -01) and National Environment Research Council (NERC) (Grant # NE/R009376/1). The authors are grateful to Royal Society, UK and Grand Challenges Canada for their financial support

Identification of pathogen genomic variants through an integrated pipeline

Background: Whole-genome sequencing represents a powerful experimental tool for pathogen research. We present methods for the analysis of small eukaryotic genomes, including a streamlined system (called Platypus) for finding single nucleotide and copy number variants as well as recombination events. Results: We have validated our pipeline using four sets of Plasmodium falciparum drug resistant data containing 26 clones from 3D7 and Dd2 background strains, identifying an average of 11 single nucleotide variants per clone. We also identify 8 copy number variants with contributions to resistance, and report for the first time that all analyzed amplification events are in tandem. Conclusions: The Platypus pipeline provides malaria researchers with a powerful tool to analyze short read sequencing data. It provides an accurate way to detect SNVs using known software packages, and a novel methodology for detection of CNVs, though it does not currently support detection of small indels. We have validated that the pipeline detects known SNVs in a variety of samples while filtering out spurious data. We bundle the methods into a freely available package

An analysis of the methods used by John William De Forest in translating his personal war experiences into realistic fiction as shown in Miss Ravenel\u27s conversion.

During the last half of the nineteenth century, novels, short stories, articles and poems written by John William De Forest appeared in the pages of such popular magazines as Harper\u27s, The Atlantic Monthly, and The Galaxy, along with literary contributions from Mark Twain, Whittier, Longfellow. Henry James. and William Dean Howells. De Forest, however, has been forgotten by both the reading public and the literary historians since that time, while the literary reputations of the other men have increased; yet it is to this obscure writer that modern critics such as Carl Van Doren, Alexander Cowie, Arthur Quinn. and Van Wyck Brooks have turned in attempting to trace the growth of realism in the American novel. De Forest, born in 1826 and privately educated, travelled widely throughout Europe and the Near East, returning to his native Connecticut to record his experiences in two travel books. Besides these two books he had written prior to the Civil War two novels and a history of the Indians of his state. Unlike the other writers of this period, De Forest took an active part in the war. serving as a captain in the Union army for three years and an officer of the Freedmen\u27s Bureau in South Carolina for three more. He recorded his military experiences and impressions in the letters which he wrote to his wife and to other members of his family with the intention of collecting these letters and papers later and publishing them. He also found time to write articles describing his experiences which were published in the various literary magazines of the day

Narrative Analysis: Demonstrating the Iterative Process for New Researchers

This article demonstrates and describes an iterative process of narrative analysis for researchers who want to familiarise themselves with this methodology. The method draws on the six-step process of how to analyse a narrative, the four modes of reading a narrative and the three-sphere model of external context. The application of the method is demonstrated through describing the process of analysis of New Zealand school counsellors’ narratives of strengths-based counselling. Furthermore, this article posits that committing to a narrative analysis process of repeated and in-depth engagement with participants’ narrative data may facilitate a more robust and engaging research outcome than may otherwise have been achieved through more prescriptive methods of narrative analysis. Finally, this article highlights the use of story-map grids (tables) and models as visual aids to assist in the process of narrative analysis

Why the NHS needs adult generalists: A call for single certification in general internal medicine

As the UK NHS faces growing challenges of the ageing population and escalating healthcare costs, we examine the role of the general internal medicine (GIM) consultant in inpatient medicine. We argue that the reintroduction of GIM could provide a sustainable and valuable contribution to high-quality, cost-effective inpatient care drawing on parallels from the GIM hospitalist model in the USA. Additionally, GIM expansion could contribute to improved outcomes for complex medical patients and surgical patients, as well as safety and quality initiatives