VictorJuiz/thesis huggingface dataset:
Multimodal Investigation of Chrna5 Nicotinic Receptors: Cellular and Synaptic Mechanisms of Cholinergic Modulation in the Prefrontal Cortex
Keywords: acetylcholine
electrophysiology
nicotinic receptors
optogenetics
prefrontal cortex
transcriptomics

Acetylcholine neurotransmission in the prefrontal cortex is essential for attention and executive function. Its disruption is implicated in multiple neurological disorders with serious cognitive deficits. However, there remain critical knowledge gaps in cellular and synaptic mechanisms of endogenous cholinergic modulation of prefrontal cortex, especially compared to better-characterized sensory cortical regions. In particular, the role of the alpha5 nicotinic receptor subunit encoded by Chrna5, which is expressed in deep-layer neurons in the prefrontal cortex remains unknown. Since Chrna5 is vital for higher-order cognition, it is essential to investigate the synaptic function of alpha5 nicotinic receptors and characterize Chrna5-expressing neurons mediating optimal cholinergic excitation. Here, I examine these questions using a multimodal approach comprising compound transgenics, optogenetics, patch-clamp electrophysiology, two-photon calcium imaging, and transcriptomic analyses in the mouse brain. First, I characterize prefrontal cholinergic signaling in a mouse model with attention deficits caused by genetic ablation of the alpha5 nicotinic subunit. These results identify Chrna5 as necessary for the rapid onset of endogenous cholinergic responses relevant for the fast timescales of attention. Using a nicotinic positive allosteric modulator NS9238, I successfully treat the deficit arising from Chrna5 disruption, restoring rapid onset of cholinergic neurotransmission in alpha5 knockout mice. Next, I probe the identity of Chrna5-expressing (Chrna5+) neurons and molecular determinants of their cholinergic properties. Through multiple approaches in novel Chrna5-Cre transgenic mice, I uncover a distinct population of Chrna5+ neurons with stronger and faster cholinergic responses. With single-cell RNAseq analysis, I identify these cells to be developmentally critical subplate neurons with differential expression of several GPI-anchored Lynx prototoxins. Using optophysiological approaches, I discover complex endogenous modulation of nicotinic receptors by Lynx prototoxins. Overall, this dissertation creates new understanding of prefrontal cholinergic modulation at the synaptic and cellular level. I identify the role of the alpha5 nicotinic subunit in ensuring rapid synaptic cholinergic transmission and preventing desensitization of these nicotinic responses. I discover a specialized subpopulation of Chrna5-expressing neurons with enhanced nicotinic responses that are dynamically regulated by distinct modulatory proteins. Together, my work uncovers molecular and cellular roles of Chrna5 relevant to cognition and identifies novel treatment approaches to restore cholinergic signaling.
Life Cycle Greenhouse Gas Emissions of Renewable Jet Fuels Produced in Canada
Keywords: Biofuel
Greenhouse Gas Emissions
LCA
Life Cycle Assessment
Renewable Jet Fuel
Sustainable Aviation Fuel

Modern technology has enabled the transformation of renewable biomass and waste into renewable energy for the sectors of our society that use fossil fuels the most. This thesis contributes to knowledge on renewable jet fuels (RJF) and their potential greenhouse gas (GHG) emissions reduction benefits for the aviation sector from a Canadian context. The first part of this thesis quantifies the life cycle GHG emissions of ethanol produced using corn stover, an agricultural residue. Wide ranging results of 7.9 to 45 gCO2e MJ-1 were initially determined from two fuel life cycle assessment (LCA) tools that modelled corn stover ethanol. Harmonization of model parameters and assumptions in the two LCA tools led to similar estimates of 41 – 42 gCO2e MJ-1 although these values obscured substantial differences in GHG emissions at the individual contributor level, which can impact the fuel’s performance under different regulatory regimes. Next, the thesis conducted an LCA on RJF derived from corn stover or ethanol from corn stover. The LCA modelled Ontario and Québec RJF production using these regions’ corn production data. The study determined life cycle GHG emissions of 3.5 – 5.3 gCO2e MJ-1 for the Fischer-Tropsch jet fuel pathway while the ethanol-to-jet fuel pathway resulted in 28 – 36 gCO2e MJ-1 due to greater inputs in the ethanol production process. Québec benefitted from its low carbon intensity electricity but corn stover yields in Ontario were identified as advantageous. The last two parts of the thesis assessed the life cycle GHG emissions of RJF from canola, camelina, and carinata oilseeds. Respectively, GHG emissions from each oilseed-to-RJF are 16 – 58 gCO2e MJ-1, 53 – 72 gCO2e MJ-1, and 43 – 52 gCO2e MJ-1. Canola RJF values varied due to soil carbon effects from land use and land management changes. The range of results for camelina and carinata RJF are due to using input data from many sources and differences in modelling assumptions. A scenario maximizing camelina or carinata RJF production using Canadian marginal lands is estimated to reduce GHG emissions in aviation by up to 2 million tonnes of CO2e emissions per year in 2050.
Towards Understanding the Behaviour of the External FRP-Reinforced Concrete Structures under Changing Climate Trends
Keywords: Climate Change
FRP
FRP sheet coupons
FRP wrapped members
FRP-concrete bond specimens
FRP-FRP bond specimens

Over the last thirty years or so, extensive research has been carried out on FRP sheets and concrete structures retrofitted with external FRP sheets under various loading and environmental conditions. Despite the excellent performance of FRPs in improving strength and ductility of structures under different conditions, information on the behaviour of FRPs under changing climatic trends including the global rise in temperature and increased number of freeze-thaw cycles etc. is not clearly understood. This study was undertaken to address this gap. In this study, over 200 specimens of FRP materials and FRP strengthened structures were tested under different temperature protocols. The test plan included FRP sheet coupons, FRP-FRP bond specimens, FRP-concrete bond specimens, FRP wrapped concrete cylinders, and FRP-strengthened reinforced concrete (RC) beams. Two main variables in this study were; the type of FRP (carbon FRP (CFRP) and glass FRP (GFRP)) and the temperature protocol; 1) sustained temperature (ST), 2) sustained deformation with increasing temperature (SD), 3) sustained load with increasing temperature (SL), and 4) freeze-thaw (FT) cycles. The exposure to elevated temperatures showed a sharp decrease in the mechanical properties of the FRP around the glass transition temperature (Tg) of epoxy. In contrast, freeze-thaw cycling showed a negligible impact on the FRP sheet behaviour. The results of FRP-FRP and FRP-concrete bond specimens investigated at sustained elevated temperatures and under sustained load protocols also showed reductions in the bond strength beyond the glass transition temperature. FRP wrapped concrete cylinders tested under room conditions showed remarkable improvements in strength and ductility of concrete. These gains were reduced severely at sustained elevated temperatures beyond the Tg. Again, the freeze-thaw cycles showed minimal effect on strength and ductility enhancements provided by the wraps. Results from the thermal study on shear-critical RC beams suggest that anchored FRP wraps can significantly improve the shear capacity of the beams at room temperature but that will reduce at a temperature of 60oC. In the analytical part of this study, models were developed to estimate the temperature reduction factors for FRP materials and FRP strengthened concrete members subjected to various temperature conditions.
Fixed Target Sample Delivery for Serial Crystallography and Ultrafast Study of Bismuth by Electron Diffraction
Keywords: fixed target
protein crystallography
sample delivery system
Serial Crystallography
ultrafast electron diffraction
X-ray Diffraction

This thesis reports on developing a fixed target sample delivery system utilized in X-ray crystallography and the ultrafast study of lattice dynamics in bismuth crystals upon photoexcitation by ultrafast electron diffraction (UED). The advent of novel ultrabright X-ray sources, such as the X-ray free electron laser (XFEL), necessitated the development of a platform for rapid and reliable delivery of protein crystals employed in the scheme known as serial femtosecond crystallography (SFX). The development of a micropatterned silicon-based crystallography chip constructed by nano-fabrication methods combined with spectroscopic mapping is outlined in the scope of this thesis. The crystallography chip capable of trapping more than 25000 crystals with the help of spectroscopic mapping more effectively exploits the expensive XFEL beam time by providing a significant improvement of the X-ray hit rate. This fixed target method enables the study of proteins with more demanding conditions by minimizing the sample consumption and reducing the stress-induced damage due to crystal handling. The application of the crystallography chip for resolving the structure of carboxy myoglobin, along with the further implementation of the crystallography chip in synchrotron light sources, is discussed. Besides developing a platform for serial crystallography, the ultrafast dynamics of bismuth crystal upon laser excitation are investigated in the second part of this thesis. It has been shown that by laser excitation of the bismuth crystal's valence electrons above 2.5 percent, a significant atomic movement in the diagonal axis of the crystal's unit cell is initiated due to a Peierl distortion reversal. The increased electronic temperature alters the electronic energy surface, enabling large amplitude movement of the atoms up to 40 picometers. This significant atomic displacement leads to the rise of anisotropic disorder in (-110) crystallographic direction, plus entering the lattice into a more symmetric state. Furthermore, the role of strong phonon-phonon interaction in the emergence of this disorder and the distribution of the energy in the lattice is investigated. Finally, the use of the fast collapse of (-110) diffraction peaks for pump and probe arrival time determination is described. The implementation of a silicon nitride chip to facilitate rapid data collection in an irreversible regime for the application of time zero determination is extensively discussed.
Navigating Academic Leadership Hierarchy: Exploring Black Male Faculty Members’ Advancement to Senior-Level Leadership Positions in Ontario Universities
Keywords: Anti-Black Racism
Black male faculty
Black men
Critical Race Theory
Navigating Leadership
Racialized faculty

The purpose of this study was to explore how Black male faculty members navigated the academic leadership hierarchy to attain senior-level leadership in Ontario universities. The literature highlighted the underrepresentation of Black male faculty members in senior-level leadership, the product of racial inequities and discrimination despite institutional commitments to equity in Canadian universities. Critical race theory (CRT) underpinned this study and acted as a vehicle to understand the impact of racism, anti-Black racism and oppression on Black men who aspired to leadership positions in academia. Inevitably, this study documented ways to disrupt and dismantle systemic racism that impeded the advancement opportunities of Black male faculty members in senior-level leadership in academia. Interviews with 11 Black male faculty members in senior-level leadership revealed that Black men experience major barriers/challenges in academia but were able to successfully advance into senior-level leadership because of numerous navigating strategies they employed.
Robust, pH-responsive Hydrogels as Actuators for Small-scale Medical Devices
Keywords: Hydrogel actuators
Magnetics
Mechanism design
Microrobotics
Physical intelligence
Wireless capsules

Miniaturization of medical devices as minimally invasive tools for disease diagnosis and treatment can lead to improved patient experience and outcomes. However, its size limits the available power to drive onboard systems and wireless power transfer via electromagnets is challenging due to scaling effects and range dependency. Chemical reactions have been used as onboard power. However, this method can generate undesired waste products in the human body. There is a need for actuators that use minimal power with minimal waste generation to impart functionality in miniature medical devices. The proposed project is to develop pH-responsive hydrogels and combine them with magnets for a novel hybrid hydrogel magnet actuator. The environmentally responsive hydrogels will add functionality without additional power and minimal volume uptake. The magnets will enable a fast mechanism response. In this work, a pH-responsive hydrogel that swelled in basic pH was developed, used in a hybrid hydrogel magnet actuator, and applied to an automatic fluid sampling capsule. An analytical model was also formulated to predict the hydrogel forces and swelling for actuator design.
Mitigating Greenwashing Concerns in the Green Bond Market
Keywords: ESG transparency and accountability
green bond standard
green finance

This dissertation examines whether the issuers of high-quality green bonds differentiate themselves by bonding with two reputable organizations that impose high green bond transparency standards -- the Climate Bonds Initiative (CBI) and the Luxembourg Green Exchange (LGX), and whether the bonding mechanism effectively mitigates investors' greenwashing concerns. I document evidence that is consistent with a separating equilibrium. Specifically, I find that the bonding issuers (i.e., issuers that obtain CBI certifications for their green bonds or list their green bonds on LGX) demonstrate higher post-issuance transparency and a larger reduction in carbon emissions while also receiving a larger green premium than the non-bonding issuers. Further analyses document differences between the CBI and LGX regimes. The CBI regime, which requires certification against a green taxonomy but allows for private communication, is more effective at screening issuers that achieve larger carbon reduction, whereas the LGX regime, which accepts broad categories of green projects but requires public disclosure on a centralized platform, is more effective at screening issuers that provide higher post-issuance transparency. Interestingly, only the LGX-listed green bonds receive a significant green premium. Moreover, green premium is more concentrated in the LGX-listed green bonds with high ex-ante transparency commitment. Furthermore, in the secondary market, green bonds from issuers that end up providing high post-issuance transparency tend to have higher liquidity. The CBI-certified or LGX-listed green bonds with high post-issuance transparency tend to have even larger liquidity benefits. Taken together, consistent with prior survey evidence in Chiang (2017) and Sangiorgi and Schopohl (2021), the findings in this dissertation corroborate that high post-issuance transparency may effectively mitigate investors’ greenwashing concerns, facilitate low-cost environmental financing, and bolster market liquidity.
Exploring the Development of Coach-Parent Relationships in Organized Competitive Youth Team Sports
Keywords: Coach-Parent Relationship
Coaching
Competitive Youth Sports
Grounded Theory
Qualitative Research
Sport Psychology

The purpose of this dissertation was to gain a better understanding of coach-parent relationships in organized competitive youth team sports. Two studies are presented in this dissertation to support this aim. Study 1 was a qualitative inquiry of parents’ and coaches’ perceptions of factors that affect coach-parent relationships in competitive youth sports, and involved semi-structured interviews with 41 participants: 21 coaches (5 females and 16 males, 22-64 years of age), and 20 parents (6 females and 14 males, 40-63 years of age). The results demonstrated that coaches and parents had similar views regarding the nature of a healthy coach- parent relationship, and that the coach-parent relationship could be influenced by factors that are related to coaches and parents’ behaviours and their interpersonal interactions. Parents’ socioeconomic status and occupation, coaches’ age and gender, and the perceived professionalization of youth sport appeared to influence the coach-parent relationship. Participants’ descriptions of their experiences revealed an imbalanced power dynamic among parents, coaches, and athletes, with parents and athletes having less power than coaches. Study 2 was a grounded theory of the developmental trajectory of the coach-parent relationship in organized competitive youth team sports, and consisted of semi-structured interviews with 20 participants: 10 coaches (2 females and 8 males, 26-50 years of age), and 10 parents (9 females and 1 male, 40-57 years of age). The results indicated that the relationship between parents and coaches develops through three stages: a) ‘Introduction and Discovery’, b) ‘Curiosity, Doubt, or Stability’, and c) ‘Engagement or Separation’. In addition, the results highlighted the role of parents, coaches, athletes, and sport administrators in development of this relationship, and brought to attention the influence of culture and generational differences among parents on the coach-parent relationship. Together, the studies presented in this dissertation provide a more comprehensive understanding of coach-parent interactions in organized competitive youth team sports, and build the foundation for future research and interventions designed to enhance the quality of coach-parent relationships in various contexts.
Investigating Causal Relations between EEG Features and Working Memory
Keywords: Causality
Classification
Electroencephalography
Machine Learning
Working Memory

Working memory is essential to perform higher-order complex cognitive tasks. A deficit in working memory yields difficulties in performing daily activities and it is an indicator of cognitive decline. Thus, extensive research has focused on approaches to improve working memory. Among these approaches non-invasive brain stimulation (NIBS) has been widely explored. However, the efficiency and reliability of NIBS across studies have not been well established. One reason could be intervening the improper neurophysiological mechanisms of working memory across individuals. Ultimately, for an optimum NIBS, it is essential to target personalized neurophysiological mechanisms that have causal relations to performance. Therefore, the overall objective of my thesis is to use electroencephalography (EEG) signals that recorded while performing N-back working memory task to determine novel neurophysiological targets for NIBS for improving performance.In the first study, we assessed the relative roles of three EEG markers that represent distinct neurophysiological mechanisms of working memory. We investigated the roles of theta-gamma coupling (TGC) representing ordering of information, alpha event-related de-synchronization (ERD) representing interference inhibition, and theta event-related synchronization (ERS) representing cognitive control in preforming N-back. The results of this study demonstrate that TGC could be a potential target for NIBS as it shows an association with N-back performance independent of other EEG markers in both younger and older healthy adults. In the second study, to identify potential targets for personalized NIBS, we used a machine learning-based approach to identify individual-specific neurophysiological correlates of N-back performance. We identified distinct EEG markers, including ERD and ERS from various oscillations and brain regions that predict performance at the individual level. In the third study, to further optimize the targets for personalized NIBS, we used a graphical causal model to identify individual-specific neurophysiological features that cause the performance. The results of this study suggest that entraining gamma oscillations using multiple electrodes over the temporal cortex to generate more causal gamma oscillations and not necessarily increasing the power of these oscillations could result in more effective NIBS outcomes and improvement in N-back performance. Taken together, our findings provide novel targets for personalized NIBS to improve working memory performance and cognition.
Measurement of Associated Production of Higgs Bosons Decaying to Pairs of W Bosons with the ATLAS Detector at the Large Hadron Collider
Keywords: Higgs boson physics
High-energy physics

This thesis describes the measurement of Higgs boson production in association with a vector boson, WH/ZH, using the H->WW*->lvlv and H->WW*->lvqq decay channels, where l is an electron or a muon. The analysis uses proton-proton collision data at centre-of-mass energy 13 TeV delivered by the Large Hadron Collider and recorded by the ATLAS detector between 2015 and 2018, corresponding to an integrated luminosity of 139 fb^-1. The analysis is performed in several channels across 2-, 3-, and 4-lepton final states and utilizes a diverse set of multivariate techniques for signal extraction. The WH and ZH production cross sections times the H->WW* branching ratio are measured to be 0.13+0.08/-0.07(stat.)+0.05/-0.04(sys.) pb and 0.31+0.09/-0.08(stat.)+/-0.03(sys.) pb, respectively, in agreement with the Standard Model expectations.