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You searched for +publisher:"Dalhousie University" +contributor:("Dr. Axel D. Becke"). Showing records 1 – 3 of 3 total matches.

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Dalhousie University

1. Taylor, Alexis. Theoretical Investigations of Non-Covalent Interactions: From Small Water Clusters to Large DNA Quadruplexes.

Degree: PhD, Department of Chemistry, 2010, Dalhousie University

The chemical bonds that hold molecules together are composed of electrons, and in order to study these microscopic systems, electronic structure calculations are often employed. This thesis describes the results from several studies that use computational techniques to investigate a variety of bonding interactions. The systems presented range from small water clusters to large DNA quadruplexes. High-level computational techniques, such as ab initio and density functional theory methods, were applied as well as the quantum theory of atoms in molecules (AIM). AIM uses the gradient to analyze the electron density, partitioning the molecule into atomic fragments. Once the system is partitioned, individual atomic contributions to molecular properties can be determined. Furthermore, bonding interactions can be identified by the presence of a specific type of critical point within the topology. These two facets of AIM are exploited throughout this thesis. The first project presented is a theoretical investigation of the exact electronic structure of hydrated electrons. Whether the excess electron resides within a central cavity or is smeared out over the surface of the cluster remains a contentious issue. In an attempt to investigate this dilemma from a novel viewpoint, AIM was used to analyze the electron density of small anionic water clusters up to ten water molecules. The results suggest that the preferred site of binding is dictated by the relative orientation of the non-hydrogen-bonded hydrogen atoms. At the other end of the spectrum, the largest systems investigated were several guanine quadruplexes that can form in telomeric regions of DNA. In light of the attention these structures have received as potential therapeutic agents, a clear understanding of their formation is mandatory. The study presented here is a detailed investigation of the electronic energy changes associated with the folding of the quadruplex from the single-stranded telomere. After devising a novel method to display the atomic energy data, several interesting trends in the energy changes were identified. Ultimately, the data presented could help to guide future drug development endeavours, highlighting one of the many practical applications of computational methods. Advisors/Committee Members: Dr. Stacey D. Wetmore (external-examiner), Dr. Mark Stradiotto (graduate-coordinator), Dr. Axel D. Becke (thesis-reader), Dr. T. Bruce Grindley (thesis-reader), Dr. Donald F. Weaver (thesis-reader), Dr. Russell J. Boyd (thesis-supervisor), Not Applicable (ethics-approval), Yes (manuscripts), Yes (copyright-release).

Subjects/Keywords: Computational chemistry; ab initio; DFT; solvated electron; guanine quadruplexes

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

APA (6th Edition):

Taylor, A. (2010). Theoretical Investigations of Non-Covalent Interactions: From Small Water Clusters to Large DNA Quadruplexes. (Doctoral Dissertation). Dalhousie University. Retrieved from http://hdl.handle.net/10222/12736

Chicago Manual of Style (16th Edition):

Taylor, Alexis. “Theoretical Investigations of Non-Covalent Interactions: From Small Water Clusters to Large DNA Quadruplexes.” 2010. Doctoral Dissertation, Dalhousie University. Accessed July 15, 2020. http://hdl.handle.net/10222/12736.

MLA Handbook (7th Edition):

Taylor, Alexis. “Theoretical Investigations of Non-Covalent Interactions: From Small Water Clusters to Large DNA Quadruplexes.” 2010. Web. 15 Jul 2020.

Vancouver:

Taylor A. Theoretical Investigations of Non-Covalent Interactions: From Small Water Clusters to Large DNA Quadruplexes. [Internet] [Doctoral dissertation]. Dalhousie University; 2010. [cited 2020 Jul 15]. Available from: http://hdl.handle.net/10222/12736.

Council of Science Editors:

Taylor A. Theoretical Investigations of Non-Covalent Interactions: From Small Water Clusters to Large DNA Quadruplexes. [Doctoral Dissertation]. Dalhousie University; 2010. Available from: http://hdl.handle.net/10222/12736


Dalhousie University

2. Knackstedt, Dane. Investigations of Phosphenium Insertion into Phosphorus-Phosphorus Bonds.

Degree: MS, Department of Chemistry, 2011, Dalhousie University

Despite many drawn parallels between carbon and phosphorus, the development of catena-phosphorus chemistry is superficially explored when compared to carbon. This lack of progression is especially highlighted for cationic phosphorus frameworks, as neutral and anionic phosphorus frameworks have been studied to a much greater extent. This stresses cationic catena-phosphorus frameworks as important molecules for an improved understanding of fundamental phosphorus chemistry. Recent advancements in synthetic methods demonstrate that phosphorus frameworks of this type are viable target molecules. Furthermore, the precedence of a variety of new cationic catena-phosphorus frameworks by such methods exemplify their versatility. Here, novel 1,3-diphosphino-2-phosphonium [R2P-PR2-PR2]+, 2-phosphino-1,3-diphosphonium [R3P-PR-PR3]+ and cyclo-triphosphinophosphonium [R2P(RP)3]+ cations have been isolated and characterized in order to study the insertion of phosphenium cations into the phosphorus-phosphorus bonds of catena-phosphines. Advisors/Committee Members: Dr. Axel D. Becke (external-examiner), Dr. Mark Stradiotto (graduate-coordinator), Dr. Russell J. Boyd (thesis-reader), Dr. Kevin R. Grundy (thesis-reader), Dr. James A. Pincock (thesis-reader), Dr. Neil Burford (thesis-supervisor), Not Applicable (ethics-approval), Not Applicable (manuscripts), Not Applicable (copyright-release).

Subjects/Keywords: Inorganic; Synthetic; Cations; Main Group; Phosphorus

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

APA (6th Edition):

Knackstedt, D. (2011). Investigations of Phosphenium Insertion into Phosphorus-Phosphorus Bonds. (Masters Thesis). Dalhousie University. Retrieved from http://hdl.handle.net/10222/13503

Chicago Manual of Style (16th Edition):

Knackstedt, Dane. “Investigations of Phosphenium Insertion into Phosphorus-Phosphorus Bonds.” 2011. Masters Thesis, Dalhousie University. Accessed July 15, 2020. http://hdl.handle.net/10222/13503.

MLA Handbook (7th Edition):

Knackstedt, Dane. “Investigations of Phosphenium Insertion into Phosphorus-Phosphorus Bonds.” 2011. Web. 15 Jul 2020.

Vancouver:

Knackstedt D. Investigations of Phosphenium Insertion into Phosphorus-Phosphorus Bonds. [Internet] [Masters thesis]. Dalhousie University; 2011. [cited 2020 Jul 15]. Available from: http://hdl.handle.net/10222/13503.

Council of Science Editors:

Knackstedt D. Investigations of Phosphenium Insertion into Phosphorus-Phosphorus Bonds. [Masters Thesis]. Dalhousie University; 2011. Available from: http://hdl.handle.net/10222/13503


Dalhousie University

3. Martin, Erin. The behaviour of neurologic water during axonal and synaptic neurotransmission: An in silico study.

Degree: MS, Department of Chemistry, 2011, Dalhousie University

Water is known to take on highly organized structures to influence the reactivity of chemical and biological systems; despite this, water is often only implicitly or approximately included in theoretical studies of biochemical systems, if not omitted entirely. Many of the current models for biological processes predate an understanding of the complex behaviour of water, yet these models have not been updated. This thesis presents an exploration of how a better of water might affect the models used to describe neurotransmission. Two classes of systems are investigated, representing the two main categories of neurotransmission: that which occurs along the length of a neuron, and that which occurs between one neuron and another cell. Lipid bilayers are studied using molecular dynamics, and neurotransmitters are studied using Car-Parrinello molecular dynamics. The results indicate that water structures may play a more specific role in neurotransmission than was previously thought. Advisors/Committee Members: n/a (external-examiner), Dr. Mark Stradiotto (graduate-coordinator), Dr. Axel D. Becke (thesis-reader), Dr. Russell J. Boyd (thesis-reader), Dr. D. Jean Burnell (thesis-reader), Dr. Donald F. Weaver (thesis-supervisor), Not Applicable (ethics-approval), Not Applicable (manuscripts), Not Applicable (copyright-release).

Subjects/Keywords: Molecular dynamics; Car-Parrinello Molecular Dynamics; Myelin sheath; Gamma-aminobutyric acid; Acetylcholine; Water

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

APA (6th Edition):

Martin, E. (2011). The behaviour of neurologic water during axonal and synaptic neurotransmission: An in silico study. (Masters Thesis). Dalhousie University. Retrieved from http://hdl.handle.net/10222/14091

Chicago Manual of Style (16th Edition):

Martin, Erin. “The behaviour of neurologic water during axonal and synaptic neurotransmission: An in silico study.” 2011. Masters Thesis, Dalhousie University. Accessed July 15, 2020. http://hdl.handle.net/10222/14091.

MLA Handbook (7th Edition):

Martin, Erin. “The behaviour of neurologic water during axonal and synaptic neurotransmission: An in silico study.” 2011. Web. 15 Jul 2020.

Vancouver:

Martin E. The behaviour of neurologic water during axonal and synaptic neurotransmission: An in silico study. [Internet] [Masters thesis]. Dalhousie University; 2011. [cited 2020 Jul 15]. Available from: http://hdl.handle.net/10222/14091.

Council of Science Editors:

Martin E. The behaviour of neurologic water during axonal and synaptic neurotransmission: An in silico study. [Masters Thesis]. Dalhousie University; 2011. Available from: http://hdl.handle.net/10222/14091

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