Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

Language: English

You searched for +publisher:"Dalhousie University" +contributor:("Dr. Donald F. Weaver"). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


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

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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 August 08, 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. 08 Aug 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 Aug 08]. 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. 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

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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 August 08, 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. 08 Aug 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 Aug 08]. 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

3. Crawford, Sarah M. Dipyrrins, Pyrrolyldipyrrins, Prodigiosenes and Their Complexes.

Degree: PhD, Department of Chemistry, 2012, Dalhousie University

Dipyrrins, pyrrolyldipyrrins and prodigiosenes are a closely related series of molecules: pyrrolyldipyrrins are dipyrrins with a pyrrolic substituent and prodigiosenes are a special class of pyrrolyldipyrrins with a methoxy substituent. Prodigiosenes are known for their anticancer activity, but although there have been a number of developments in their synthesis, chemical manipulation of prodigiosenes is rare. Development of a methodology for the chemical manipulation of prodigiosenes would allow a convergent synthesis of a closely related series of prodigiosenes ideal for investigations into structure activity relationships. Chemical manipulation of dipyrrins is also rare, but this is largely overcome by first converting dipyrrins to dipyrrinato complexes. The same strategy could potentially apply to pyrrolyldipyrrins and prodigiosenes, but there are very few known pyrrolyldipyrrinato complexes. Three projects were undertaken in order to investigate the chemical manipulation of dipyrrins and pyrrolyldipyrrins. The first project was to investigate the synthesis of a library of prodigiosenes by way of a convergent approach. The synthesis of a functionalized prodigiosene, with demonstrated anticancer activity, was optimized and many methods for functional group interconversion of an ester attached to the prodigiosene core were investigated. Ultimately, this method was unsuccessful in the synthesis of a library of prodigiosenes due to instability of prodigiosene intermediates. The second project was to investigate the synthesis of pyrrolyldipyrrinato complexes. A series of pyrrolyldipyrrinato tin(IV) complexes with a previously unobserved binding mode for pyrrolyldipyrrins were successfully synthesized and one complex of the series was characterized using x-ray crystallography. Although fluorescent dipyrrinato complexes, with the exception of boron difluoride complexes, are rare, all of the pyrrolydipyrrinato tin(IV) complexes were highly fluorescent with fluorescence quantum yields between 0.28 to 0.61. The third project was to develop a protection method for pyrrolyldipyrrins using dipyrrins as model compounds. A general, high yielding method was developed to remove the BF2 group from a dipyrrinato borondifluoride complex to generate a dipyrrin. Preliminary application of this deprotection methodology to prodigiosene boron difluoride complexes shows promise. This deprotection methodology allowed for the development of a new methodology for the synthesis of meso-alkyl substituted dipyrrins via meso-modification of their corresponding boron difluoride complexes. Advisors/Committee Members: Dr. Laurel Schafer (external-examiner), Dr. D. Jean Burnell (graduate-coordinator), Dr. D. Jean Burnell (thesis-reader), Dr. James A. Pincock (thesis-reader), Dr. Donald F. Weaver (thesis-reader), Dr. Alison Thompson (thesis-supervisor), Not Applicable (ethics-approval), Not Applicable (manuscripts), Not Applicable (copyright-release).

Subjects/Keywords: Dipyrrins; Pyrrolyldipyrrins; Prodigiosenes

…research was provided by the Natural Sciences and Research Council of Canada and Dalhousie… …University. In addition, I am indebted to several members of the Department of Chemistry and would… 

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Crawford, S. M. (2012). Dipyrrins, Pyrrolyldipyrrins, Prodigiosenes and Their Complexes. (Doctoral Dissertation). Dalhousie University. Retrieved from http://hdl.handle.net/10222/15864

Chicago Manual of Style (16th Edition):

Crawford, Sarah M. “Dipyrrins, Pyrrolyldipyrrins, Prodigiosenes and Their Complexes.” 2012. Doctoral Dissertation, Dalhousie University. Accessed August 08, 2020. http://hdl.handle.net/10222/15864.

MLA Handbook (7th Edition):

Crawford, Sarah M. “Dipyrrins, Pyrrolyldipyrrins, Prodigiosenes and Their Complexes.” 2012. Web. 08 Aug 2020.

Vancouver:

Crawford SM. Dipyrrins, Pyrrolyldipyrrins, Prodigiosenes and Their Complexes. [Internet] [Doctoral dissertation]. Dalhousie University; 2012. [cited 2020 Aug 08]. Available from: http://hdl.handle.net/10222/15864.

Council of Science Editors:

Crawford SM. Dipyrrins, Pyrrolyldipyrrins, Prodigiosenes and Their Complexes. [Doctoral Dissertation]. Dalhousie University; 2012. Available from: http://hdl.handle.net/10222/15864

.