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You searched for subject:(Sulfur intermediates). Showing records 1 – 2 of 2 total matches.

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University of Windsor

1. Simard, Daniel James. Computational Investigations on Enzymatic Catalysis and Inhibition.

Degree: MS, Chemistry and Biochemistry, 2015, University of Windsor

Enzymes are the bimolecular “workhorses” of the cell due to their range of functions and their requirement for cellular success. The atomistic details of how they function can provide key insights into the fundamentals of catalysis and in turn, provide a blueprint for biotechnological advances. A wide range of contemporary computational techniques has been applied with the aim to characterize recently discovered intermediates or to provide insights into enzymatic mechanisms and inhibition. More specifically, an assessment of methods was conducted to evaluate the presence of the growing number 3– and 4–coordinated sulfur intermediates in proteins/enzymes. Furthermore, two mechanisms have been investigated, the μ-OH mechanism of the hydrolysis of dimethylphosphate in Glycerophosphodiesterase (GpdQ) using five different homonuclear metal combinations Zn(II)/Zn(II), Co(II)/Co(II), Mn(II)/Mn(II), Cd(II)/Cd(II) and Ca(II)/Ca(II) as well as a preliminary study into the effectivness of boron as an inhibitor in the serine protease reaction of class A TEM-1 β-lactamases. Advisors/Committee Members: Gauld, James.

Subjects/Keywords: Computational enzymology; Phosphate cleavage; Quantum mechanics/molecular mechanics; Sulfur intermediates; β-lactamases

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APA (6th Edition):

Simard, D. J. (2015). Computational Investigations on Enzymatic Catalysis and Inhibition. (Masters Thesis). University of Windsor. Retrieved from https://scholar.uwindsor.ca/etd/5440

Chicago Manual of Style (16th Edition):

Simard, Daniel James. “Computational Investigations on Enzymatic Catalysis and Inhibition.” 2015. Masters Thesis, University of Windsor. Accessed December 08, 2019. https://scholar.uwindsor.ca/etd/5440.

MLA Handbook (7th Edition):

Simard, Daniel James. “Computational Investigations on Enzymatic Catalysis and Inhibition.” 2015. Web. 08 Dec 2019.

Vancouver:

Simard DJ. Computational Investigations on Enzymatic Catalysis and Inhibition. [Internet] [Masters thesis]. University of Windsor; 2015. [cited 2019 Dec 08]. Available from: https://scholar.uwindsor.ca/etd/5440.

Council of Science Editors:

Simard DJ. Computational Investigations on Enzymatic Catalysis and Inhibition. [Masters Thesis]. University of Windsor; 2015. Available from: https://scholar.uwindsor.ca/etd/5440


University of Illinois – Urbana-Champaign

2. Huff, Laura. Identification of battery products and intermediates through NMR spectroscopy.

Degree: PhD, 0335, 2014, University of Illinois – Urbana-Champaign

This dissertation focuses on identification of products and intermediates formed in the lithium-oxygen, lithium-sulfur, and lithium-ion battery systems. Interest in the species formed in cycled batteries is motivated by incomplete knowledge of the discharge mechanisms and products formed, where knowledge of these species can allow the design of more efficient batteries with greater specific energy density. The greater interest in batteries with high energy storage capabilities is motivated by the current social and economic goal of creating a sustainable energy future that is powered by renewable energy sources and energy storage devices. The first section focuses on identification of species formed in lithium-oxygen (Li-O2) batteries. Discharged lithium–O2 battery cathodes are investigated with different catalysts present including Pd, α-MnO2 and CuO, and containing two different electrolyte solvents, 1:1 ethylene carbonate/dimethyl carbonate (EC/DMC) and tetraethylene glycol dimethyl ether (TEGDME). Solid-state 6Li magic angle spinning (MAS) NMR spectroscopy is used identify lithium products that are formed in the cathodes and differences between products formed with different catalysts and solvents present. Significant differences in the products formed in Li–O2 cathodes with the two different solvents, EC/DMC and TEGDME, are described. Due to the small chemical shift range of lithium, the exact speciation is difficult to obtain from 6Li MAS NMR data alone. Fitting of the 6Li NMR peaks with tested Li-oxide powder standards indicates that Li–O2 cathodes discharged in EC/DMC produce primarily Li2CO3 as a lithium product and those discharged in TEGDME produce primarily Li2O2. Solution 2-D correlation 1H–13C NMR spectroscopy techniques allow for determination of side-products produced in Li–O2 cathodes, which are presented. The second section focuses on identification of products and intermediates formed in lithium-sulfur (Li-S) battery cathodes using solid-state 6Li and 33S MAS NMR spectroscopy. Cathodes are stopped and measured ex-situ at three different potentials during battery discharge to obtain chemical shifts and T2 relaxation times of the products formed, which are discussed. The chemical shifts in the spectra of both 6Li and 33S NMR demonstrate that long-chain, soluble lithium polysulfide species formed at the beginning of discharge are indistinguishable from each other (similar chemical shifts), while short-chain, insoluble polysulfide species that form at the end of discharge (presumably Li2S2 and Li2S) have a different chemical shift, thus distinguishing them from the soluble long-chain products. Spin-spin T2 relaxation measurements of discharged cathodes are also presented, which demonstrate that T2 relaxation rates form two groupings and support previous conclusions that long-chain polysulfide species are converted to shorter chain species during discharge. Through the complementary techniques of 1-D 6Li and 33S solid-state MAS NMR spectroscopy, solution 7Li and 1H NMR spectroscopy, and… Advisors/Committee Members: Gewirth, Andrew A. (advisor), Gewirth, Andrew A. (Committee Chair), Girolami, Gregory S. (committee member), Moore, Jeffrey S. (committee member), Bailey, Ryan C. (committee member).

Subjects/Keywords: Lithium-oxygen (Li-O2) battery; Lithium-sulfur (Li-S) battery; lithium-ion (Li-ion) battery; Nuclear magnetic resonance (NMR); Nuclear magnetic resonance (NMR) spectroscopy; solid-state Nuclear magnetic resonance (NMR); Lithium-7 (7Li); Lithium-6 (6Li); Sulfur-33 (33S); Carbon-13 (13C); products; intermediates; secondary electrolyte interphase (SEI); 2-D Nuclear magnetic resonance (NMR) spectroscopy; identification of battery products

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Huff, L. (2014). Identification of battery products and intermediates through NMR spectroscopy. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/50463

Chicago Manual of Style (16th Edition):

Huff, Laura. “Identification of battery products and intermediates through NMR spectroscopy.” 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed December 08, 2019. http://hdl.handle.net/2142/50463.

MLA Handbook (7th Edition):

Huff, Laura. “Identification of battery products and intermediates through NMR spectroscopy.” 2014. Web. 08 Dec 2019.

Vancouver:

Huff L. Identification of battery products and intermediates through NMR spectroscopy. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2019 Dec 08]. Available from: http://hdl.handle.net/2142/50463.

Council of Science Editors:

Huff L. Identification of battery products and intermediates through NMR spectroscopy. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/50463

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