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Understanding the global and local evidence on the process of student engagement in Health Promoting Schools
(2025-06-23) Kontak, Julia; Yes; Doctor of Philosophy; Faculty of Health; Received; Dr. Antony Card; Yes; Dr. Camille Hancock-Friesen; Dr. Becky Feicht; Dr. Sara Kirk
Health Promoting Schools (HPS) is a whole-school approach that facilitates environments for student health and learning. Despite evidence supporting outcomes of student engagement, a key component of HPS, little is known regarding process factors that lead to these benefits. In Nova Scotia, Canada, UpLift (2019 – 2024), a school-community-university partnership was formed to catalyze HPS, with a focus on student engagement. To amplify student engagement, Youth Engagement Coordinators (YECs) were hired, and Student Action Grants were established. The aim of this dissertation was to understand the process of student engagement in HPS at the global and local level. First, a scoping review was conducted to globally map and characterize the process of student engagement in HPS. Of the 50 sources analyzed, process factors related to participatory mechanisms for engagement included reflection and visioning, co-determining priorities and action-oriented learning. Second, a co-design approach using a transformative lens was employed to understand perspectives from students (n = 9, grades 7 - 11) and YECs (n = 6) involved in UpLift. This involved two co-design workshops where participants worked with the research team to gather, analyze, and interpret the data. Methods with students involved the draw, write and tell method, and a participatory focus group. Methods with YECs included a focus group, participatory mapping and a theming exercise. Following the workshops, reflexive thematic analysis was employed, and member reflection was conducted. Findings from the student group outlined the significance of strategies to build motivation for action, a collaborative space for youth, and adult facilitation practices. Findings from the YECs emphasized the importance of reflexivity, school culture, connections with school members, expansion on the concept of health and equitable environments for youth voice.
This dissertation provides global and contextual considerations specific to Nova Scotia on the process for student engagement in HPS. Findings highlight factors across the process spectrum, from foundational considerations including adult positioning and school culture, to more specific implementation strategies related to collaborative decision-making. Findings highlight the relationship between student health promotion competencies and youth agency. These findings will directly build the knowledge base and contribute to local student engagement efforts in HPS.
Bathymetric Anomaly Detection Towards Simultaneous Localization and Mapping on Autonomous Underwater Vehicles
(2025-06-23) Cain, Nolan; Not Applicable; Master of Applied Science; Department of Mechanical Engineering; Not Applicable; na; Not Applicable; Dr. Ted Hubbard; Dr. Guy Kember; Dr. Mae Seto; Dr. Robert Bauer
Autonomous underwater vehicles (AUVs) are uncrewed vehicles that can dive to deep depths or under ice to map the seafloor in the Arctic. Due to the lack of global navigation satellite systems (GNSS) underwater, AUV's rely on inertial navigation to estimate their position. Inertial navigation suffers from unbounded error drift. Simultaneous localization and mapping (SLAM) can be used to correct the AUV's positional estimate by repeatedly observing landmarks in its surrounding terrain. Bathymetry has been used to define landmarks for underwater navigation using feature extraction techniques designed for optical imagery. This thesis describes the development of a novel anomaly detector, `Bathymetric Anomalies from Anti-Motifs' (BAAM), that is purpose-built to detect unique bathymetric landmarks. BAAM exploits known bathymetric motifs (commonly repeated patterns) to detect bathymetric anomalies which can be used as landmarks for SLAM. Bathymetric motifs were extracted from a region of Delaware Bay bathymetry using a 2-D adapted matrix profile algorithm, geometric transformation- and scale-invariant image matrix profile (GTSI-IMP), that was developed in this thesis. The ability to associate landmarks, of BAAM and existing optical feature extraction algorithms, was evaluated using semi-synthetic sonar images of a separate region of Delaware Bay bathymetry. For the conditions used in this research, the BAAM detector combined with the binary robust invariant scalable keypoints (BRISK) descriptor produced more correct matches than many of the optical feature extraction methods. However, the scale-invariant feature transform (SIFT) detector combined with the BRISK descriptor was found to produce the most correct matches in both the noise-free and noisy semi-synthetic sonar images. Despite SIFT-BRISK's ability to produce more correct matches than BAAM-BRISK on these semi-synthetic sonar images, the landmarks identified in the Delaware Bay bathymetry using BAAM were found to be more unique (anomalous) than those identified using SIFT.
Synthesis of Phosphino(Silyl) Ligated Nickel and Manganese Complexes for the Catalytic Hydrofunctionalization of Alkenes
(2025-06-17) Saunders, Tyler; Not Applicable; Doctor of Philosophy; Department of Chemistry; Not Applicable; Johanna Blacquiere; Yes; Mark Stradiotto; Saurabh Chitnis; Norman Schepp; Laura Turculet
Transition metal catalysts play a key role in the synthesis of value-added products from abundant raw materials. While homogeneous catalysts that feature scarce metals such as Pd, Pt, Rh, and Ru have proven effective, recent focus on sustainability has led to interest in utilizing Earth-abundant 3d-metals such as Mn, Fe, Co, and Ni. Multidentate phosphino(silyl) ligands under investigation in the Turculet group have proven useful in 3d-metal mediated catalysis. This document details the development of new tridentate PSiN and bidentate PSi supported Ni and Mn complexes for application in hydrofunctionalization catalysis.
Nickel complexes supported by a new PSiN ligand that features a quinolyl donor, as well as complexes supported by the bidentate CyPSi (CyPSi = κ2-(2-Cy2PC6H4)SiiPr2) ligand were shown to be effective pre-catalysts for alkene tandem isomerization-hydroboration. Deuterium labeling experiments support a Ni-mediated alkene chain-walking mechanism involving reversible alkene insertion/β-hydride elimination. Borylation occurs exclusively at a terminal position, affording high selectivity. Nickel complexes supported by a new PSiInd ligand featuring an indolyl backbone were also pursued, and these complexes along with (CyPSi)Ni species were screened in alkene hydrogenation catalysis. A variety of sterically hindered, unfunctionalized alkenes were readily hydrogenated under mild conditions. Deuteration experiments highlight the occurrence of background chain-walking, similar to that observed in the previous hydroboration studies.
The synthesis of chiral phosphino(silyl) Ni complexes for application in asymmetric catalysis was also targeted. In this regard, a new (BIPHEN-SilaPhos)Ni(η3-C8H13) complex is described. This complex and the previously synthesized ((S,S)-TADDOL-SilaPhos)Ni(η3-C8H13) were applied in the asymmetric hydrogenation of (Z)-2-acetamido-3-arylacrylates to access chiral α-amino acid esters. SilaPhos ligation represents a new approach to chiral ligands featuring chirality at a Si donor. The (S,S)-TADDOL-SilaPhos ligated Ni complex afforded the desired products in near quantitative yields with excellent enantioselectivity (up to 98:2 er). Both direct and transfer hydrogenation with iPrOH as the hydrogen source are shown to be viable pathways for this reactivity.
Progress towards the synthesis of Mn complexes supported by multidentate phosphino(silyl) ligation is also described. Mn(I) tricarbonyl complexes supported by CyPSiP (CyPSiP = κ3-(2-Cy2PC6H4)2SiMe) and PSiN ligation were synthesized and structurally characterized. The utility of Mn pre-catalysts in alkyne semi-hydrogenation and alkene hydrogenation was investigated. In situ generated Mn(II) dialkyl complexes featuring CyPSiP and PSiN ligation are shown to be active in the catalytic hydrogenation of a range of terminal alkenes.
Optogenetic-Based Models of Arrhythmia-Induced Cardiomyopathy in Larval Zebrafish
(2025-06-19) Savoie, Emma; Not Applicable; Master of Science; Department of Physiology & Biophysics; Not Applicable; Keith Brunt; Not Applicable; Thomas Pulinilkunnil; Ketul Chaudhary; Alexander Quinn
Arrhythmia-induced cardiomyopathy (AiCM) has recently emerged as a distinct subset of cardiomyopathy, resulting from chronic tachycardia or high ectopic burden, which leads to structural and functional changes in the heart. Traditional experimental models of AiCM rely on invasive techniques, such as implantable pacemakers, which are low-throughput and technically challenging. In contrast, optogenetics allows for light-based cardiac pacing, which, in transparent zebrafish larvae, offers a non-invasive, high-throughput platform for studying AiCM and identifying novel pharmacological treatments. In this study, we aimed to develop in vivo optogenetic models of AiCM using larval zebrafish to investigate the effects of arrhythmias on cardiac function, structure, and gene expression. We utilized zebrafish with cardiac-specific expression of cation-nonspecific channelrhodopsin-2 (ChR2) or chloride-specific anion channelrhodopsin-1 (ACR1) and exposed them to three arrhythmia protocols: intermittent tachypacing, a 33% ectopic burden, or a 50% ectopic burden through programmed light pulses at 2-7 days post-fertilization. GFP-expressing zebrafish exposed to the same light patterns served as controls. The mechanical function of the atrium and ventricle was assessed in live zebrafish at 7 dpf through brightfield recordings, while structural changes were evaluated in fixed samples using fluorescent microscopy. Additionally, we examined the expression of genetic biomarkers associated with cardiomyopathy using qRT-PCR. Our findings revealed that both tachypacing and ectopic pacing induced significant changes in cardiac structure, function, and gene expression. Intermittent tachypacing induced the most severe dysfunction, followed by the 50% ectopic burden and 33% ectopic burden. Across all protocols, ChR2-expressing fish showed more pronounced changes than ACR1-expressing fish. Specifically, both tachypacing and ectopic pacing resulted in increased end-diastolic area (EDA), end systolic area (ESA), stroke area (SA), and decreased ejection fraction (EF), with changes in gene expression indicative of chamber wall stretch, hypertrophy, inflammation, and fibrosis. To explore the therapeutic potential of this model, we tested the effects of fimasartan on tachypacing-induced dysfunction. Preliminary results demonstrated that 50µM fimasartan improved cardiac function and attenuated structural remodeling in the zebrafish heart, highlighting the potential of this model as a high-throughput platform for therapeutic drug screening.
LRRTM4 is a member of the trans-synaptic complex between rod photoreceptors and ON bipolar cells
(2021) Agosto, MA; Wensel, TG
Leucine rich repeat transmembrane (LRRTM) proteins are synaptic adhesion molecules with roles in synapse formation and signaling. LRRTM4 transcripts were previously shown to be enriched in rod bipolar cells (BCs), secondary neurons of the retina that form synapses with rod photoreceptors. Using two different antibodies, LRRTM4 was found to reside primarily at rod BC dendritic tips, where it colocalized with the transduction channel protein, TRPM1. LRRTM4 was not detected at dendritic tips of ON-cone BCs. Following somatic knockout of LRRTM4 in BCs by subretinal injection and electroporation of CRISPR/Cas9, LRRTM4 was abolished or reduced in the dendritic tips of transfected cells. Knockout cells had a normal complement of TRPM1 at their dendritic tips, while GPR179 accumulation was partially reduced. In experiments with heterologously expressed protein, the extracellular domain of LRRTM4 was found to engage in heparan-sulfate dependent binding with pikachurin. These results implicate LRRTM4 in the GPR179-pikachurin-dystroglycan transsynaptic complex at rod synapses.
Anarchists in Red Russia: The Theory and Practice of Political Violence
(2025-04-09) Fellows, Oscar