OPUS: Open Ulethbridge Scholarship

Open ULeth Scholarship (OPUS) is the University of Lethbridge's open access research repository. It contains a collection of materials related to research and teaching produced by the academic community.

Self-archiving your research in OPUS is one way to meet Open Access policies of granting agencies. It is important to retain your final, post-peer-reviewed drafts for submission to OPUS, as this is often the only version publishers will allow to be archived. Click here for information on the U of L Open Access Policy.

Check here for more information about OPUS.

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Recent Submissions

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Are monophospha(III)amidines and -guanidines with ionizable hydrogens tautomeric? Towards a deeper understanding of two related hetero-element functional groups
(Wiley, 2023) Masuda, Jason D.; Amrei, Leila M.; Boeré, René T.
This paper presents definitive structural evidence for N,P(III)-monophosphaamidines in P=C and N=C isomeric forms from a combination of new syntheses, single-crystal X-ray diffraction (SC-XRD), solid-state NMR and FTIR. Evidence is also provided for C-amino-(σ2,λ3)-phosphaalkene and C-(σ3,λ3)-phosphinoimine tautomerism in solution using multi-nuclear NMR methods. Synthesis and SC-XRD structure determination of a trisubstituted N,N’,P(III)-monophosphaguanidine is presented, the first structure of a phospha(III)guanidine with two ionizable H atoms. The structural evidence is convincing for an N=C geometry, resulting in both N−H and P−H in the molecule. A detailed computational investigation using DFT methods is presented, with the goal of understanding the tautomeric structure preferences both at the fundamental level (parent molecules with all substituents on the heteroatoms being hydrogen) and using the full structures containing the very bulky 2,6-diisopropylphenyl (Dipp) substituents employed in this study. Arguments are espoused for treating phospha(III)amidines and -guanidines as new types of functional groups, similar to but distinct from the familiar organic analogues. Limited reactivity studies and a voltammetry study of one phospha(III)amidine are included with the supporting information.
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Challenging an old paradigm by demonstrating transition metal-like chemistry at a neutral nonmetal center
(Nature Portfolio, 2023) Biskup, David; Schnakenburg, Gregor; Boeré, René T.; Ferao, Arturo E.; Streubel, Rainer K.
We describe nonmetal adducts of the phosphorus center of terminal phosphinidene complexes using classical C- and N-ligands from metal coordination chemistry. The nature of the L-P bond has been analyzed by various theoretical methods including a refined method on the variation of the Laplacian of electron density ∇2ρ along the L-P bond path. Studies on thermal stability reveal stark differences between N-ligands such as N-methyl imidazole and C-ligands such as tert-butyl isocyanide, including ligand exchange reactions and a surprising formation of white phosphorus. A milestone is the transformation of a nonmetal-bound isocyanide into phosphaguanidine or an acyclic bisaminocarbene bound to phosphorus; the latter is analogous to the chemistry of transition metal-bound isocyanides, and the former reveals the differences. This example has been studied via cutting-edge DFT calculations leading to two pathways differently favored depending on variations in steric demand. This study reveals the emergence of organometallic from coordination chemistry of a neutral nonmetal center.
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Genetic-environment associations explain genetic differentiation and variation between western and eastern North Pacific Rhinoceros Auklet (Cerorhinca monocerata) breeding colonies
(Wiley, 2024) Graham, Brendan A.; Hipfner, J. Mark; Wellband, Kyle W.; Ito, Motohiro; Burg, Theresa M.
Animals are strongly connected to the environments they live in and may become adapted to local environments. Examining genetic-environment associations of key indicator species, like seabirds, provide greater insights into the forces that drive evolution in marine systems. Here we examined a RADseq dataset of 19,213 SNPs for 99 Rhinoceros Auklets (Cerorhinca monocerata) from five western Pacific and ten eastern Pacific breeding colonies. We used partial-redundancy analyses to identify candidate adaptive loci and to quantify the effects of environmental variation on population genetic structure. We identified 262 candidate adaptive loci, which accounted for 3.0% of the observed genetic variation among western Pacific and eastern Pacific breeding colonies. Genetic variation was more strongly associated with pH and maximum current velocity, than maximum sea surface temperature. Genetic-environment associations explain genetic differences between western and eastern Pacific populations, however, genetic variation within the western and eastern Pacific Ocean populations appears to follow a pattern of isolation-by-distance. This study represents a first to quantify the relationship between environmental and genetic variation for this widely distributed marine species and provides greater insights into the evolutionary forces that act on marine species.
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Structural studies of RNA-protein complexes: a hybrid approach involving hydrodynamics, scattering, and computational methods
(Elsevier, 2017) Patel, Trushar R.; Chojnowski, Grzegorz; Astha; Koul, Amit; McKenna, Sean A.; Bujnicki, Janusz M.
The diverse functional cellular roles played by ribonucleic acids (RNA) have emphasized the need to develop rapid and accurate methodologies to elucidate the relationship between the structure and function of RNA. Structural biology tools such as X-ray crystallography and Nuclear Magnetic Resonance are highly useful methods to obtain atomic-level resolution models of macromolecules. However, both methods have sample, time, and technical limitations that prevent their application to a number of macromolecules of interest. An emerging alternative to high-resolution structural techniques is to employ a hybrid approach that combines low-resolution shape information about macromolecules and their complexes from experimental hydrodynamic (e.g. analytical ultracentrifugation) and solution scattering measurements (e.g., solution X-ray or neutron scattering), with computational modeling to obtain atomic-level models. While promising, scattering methods rely on aggregation-free, monodispersed preparations and therefore the careful development of a quality control pipeline is fundamental to an unbiased and reliable structural determination. This review article describes hydrodynamic techniques that are highly valuable for homogeneity studies, scattering techniques useful to study the low-resolution shape, and strategies for computational modeling to obtain high-resolution 3D structural models of RNAs, proteins, and RNA-protein complexes.
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Examining teacher candidates' self-determined motivation to develop self-regulated learning promoting practices
(Elsevier, 2024) Brenner, Charlotte
The development of self-regulated learning leads to positive academic, social, and emotional outcomes for learners. For many educators, teaching towards self-regulated learning is challenging. This study investigated contextual and motivational features within teacher education programs that support or hinder teacher candidates’ motivation to development self-regulated learning practices. Zimmerman’s model of self-regulated learning (2008), along with Perry, Hutchinson, and Thauberger’s (2008) descriptions of self-regulated learning practices and Ryan and Deci’s (2017) self-determination theory informed this process. Codes and categories drawn from interviews, documents, and in-class observations and reported upon in previously published work was analyzed to identify themes that are supportive or constraining of teacher candidates’ motivation to develop practices that foster self-regulated learning in the classroom. Results reveal five themes: (a) opportunities for teacher candidates to see their school mentors’ formation of classroom participation structures, (b) the provision of freedom for teacher candidates to experiment with practices along with in-situ scaffold support, (c) adequate support for teacher candidates to integrate self-regulated learning content into their practice, (d) teacher candidates’ perceptions of alignment across their learning experiences, and (e) adequate time and support for teacher candidates to establish relationships in their practicum settings.