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Scanning Site Saturation Mutagenesis of the Human μ-Opioid Receptor
No full textThe human μ-opioid receptor (μOR) mediates the therapeutic and adverse effects of opioids, yet its structural determinants of function remain poorly understood. This study employed Scanning Site Saturation Mutagenesis (SSSM) to systematically analyze the role of 288 transmembrane core residues, generating a comprehensive library of 5,472 receptor variants. Using a yeast-based biosensor platform, we screened the library against the μOR agonist DAMGO to identify functional variants. Our results revealed critical insights into receptor-ligand interactions, including the identification of L178R, a variant exhibiting nearly double the signaling sensitivity of the wild-type receptor. This substitution, localized to intracellular loop 2, highlights the role of conserved residues in stabilizing receptor-G protein interactions. Additionally, we characterized non signaling variants to identify residues essential for receptor function. By integrating high-throughput sequencing and variant characterization, this platform provides a robust tool for probing receptor functionality and offers a foundation for refining opioid receptor-based drug discovery
Microplastic Entrainment in Ice Formations and Their Electrochemical Removal from Water
Get PDFSea ice can act as a temporary sink for microplastics (MPs), which also function as secondary sources and transport mediums for MPs. While field investigations have confirmed the widespread presence of MPs in ice, knowledge about their environmental fate in cold regions remains limited. This study investigates the entrainment of MPs during ice formation processes and how freezing alters their behavior in water. Additionally, an electrochemical removal technology was developed to separate MPs from water, addressing the issue at its source.
The study first explored the effects of various MP properties and environmental conditions on the entrainment and enrichment of MPs in ice under different turbulence scenarios. Results revealed that high turbulence in freshwater significantly increased the entrainment of hydrophobic MPs in ice, due to the combined influence of frazil ice and air bubbles. The hydrophobic nature of MPs led them to concentrate at the water/air or water/ice interface. However, in saline water, high turbulence inhibited the entrainment of all MP types, as loose ice structures allowed for the exchange of MPs between ice and water, resulting in rapid expulsion. In calm saline conditions, MP enrichment factors were higher compared to calm freshwater.
Next, the study examined the interactions between aquatic organic matter and MPs, focusing on how these interactions influence MP behavior during ice formation. A 28-day experiment evaluated the effects of dissolved organic matter on MP properties under UV and dark conditions. Findings revealed that aquatic organic matter adhered to MPs, with varying impacts on different MP types. Surface damage caused by physical abrasion and UV radiation improved the entrapment of MPs in ice, highlighting the critical role of MP properties in their environmental behavior.
As temperatures fluctuate, MPs stored in ice can be released, and freezing conditions can alter their properties, affecting their fate in the environment. Freezing in freshwater led to MP aggregation through physical compression, increasing particle size upon release. This aggregation enhanced buoyancy, accelerating the settling or rising velocity of MPs in water. In contrast, the presence of salt mitigated freezing effects due to the formation of a brine network within the ice structure, reducing pressure on entrapped MPs.
To address the issue of MP release into the environment via wastewater, this study developed an electrosorption (ES) technology using graphite felt electrodes to remove MPs from water. Preliminary experiments investigated the effects of flow rate, applied voltage, and electrolyte concentration on MP removal efficiency. Under optimal conditions, 96.9% of MPs were removed after 150 minutes. By analyzing the factors influencing MP removal efficiency and the underlying mechanisms using DLVO theory, this study provides a foundation for future advancements in ES technology for MP removal, with potential for real-world applications in complex environments
lateral cyclic performance and analysis of flexural-dominated reinforced masonry shear walls
Get PDFReinforced masonry shear walls (RMSWs) provide lateral stability to reinforced masonry (RM) structures, especially in seismic-prone regions. They are categorized into fully grouted (FG) and partially grouted (PG) types. While FG-RMSWs offer high strength and stiffness suitable for high-seismic zones, PG-RMSWs are more cost-effective, reducing grouted cells while balancing performance and economy. Despite their economic benefits, PG-RMSWs are mainly used in low-rise buildings due to limited research on their seismic behavior in mid- and high-rise structures. This study investigates the in-plane quasi-static and dynamic responses of flexure-dominated RMSWs, focusing on grouting (PG vs. FG), cross-sectional configurations (rectangular and with boundary elements (BEs)), and shear reinforcement setups (bond beam reinforcement (BBR) vs. bed joint reinforcement (BJR)). The goal is to optimize CSA S304 seismic design provisions and expand the application of RMSWs in mid- and high-rise buildings.
The research consists of two phases. Phase I, “Shear and Flexural Behavior Enhancement of RMSWs,” includes experimental tests on flexural-dominated PG-RMSWs under quasi-static cyclic loading, as well as masonry wallets under diagonal tension. Two PG-RMSWs with identical aspect ratios, axial stresses, and flexural capacities but different cross-sectional configurations (rectangular and with BEs) were tested. Additionally, 34 masonry assemblages and 40 prisms with varying mortar and grout strengths and reinforcement configurations were evaluated to understand their shear and compressive behaviors. Results indicated that PG-RMSWs with BJR showed ductile behavior, significant energy dissipation, and enhanced shear strength, supporting their use in mid-rise buildings and informing updates to CSA S304.
Phase II involves numerical studies to analyze the lateral cyclic response of RMSWs under quasi-static and dynamic loading using the Applied Element Method (AEM) with Extreme Loading for Structures (ELS) software. Comparisons between PG-RMSWs with BBR or BJR and FG-RMSWs with different configurations revealed that PG-RMSWs had comparable ductility and drift capacities to FG-RMSWs, achieving up to 41% material savings.
Overall, the experimental and numerical findings emphasize the need to revisit seismic design provisions and shear strength equations in CSA S304 for PG and FG masonry. This research advances the economical use of PG-RMSWs in mid- and high-rise buildings, promoting their broader application in performance-based seismic design
Implementing Oligonucleotide Synthesis on a Digital Microfluidic Device with Phosphoramidite Chemistry
No full textDNA synthesis is fundamental to synthetic biology, yet existing technologies face significant constraints in terms of sequence length, cost, and efficiency. Current technologies lack the control necessary to consolidate the oligonucleotide synthesis and DNA assembly on a single platform. In my thesis I introduce a digital microfluidics platform capable of performing DNA synthesis. This technology is enabled through the combined use of magnetized controlled pore glass beads with phosphoramidite functionalization and a non-standard set of synthesis reagents compatible with digital microfluidics. This work demonstrates evidence of reagent compatibility, magnetic pore glass characterization, and provides initial evidence of oligonucleotide synthesis on a digital microfluidic device
Machine Learning-Driven Solutions for Hydrometric and Traffic Prediction
Get PDFThis thesis explores advanced spatiotemporal machine learning techniques for traffic and hydrometric prediction using graph-based neural network models, RNN family, attention mechanism, and transformer architecture. First, a multilevel GNN-RNN architecture is proposed for traffic forecasting, effectively capturing complex spatial and temporal dependencies across urban road networks. This model significantly reduces computation time and improves prediction accuracy compared to existing methods. In the domain of hydrometric forecasting, a spatiotemporal model with an attention-augmented Graph Convolution Recurrent Neural Network (GCRN) is introduced. This model learns the connectivity between water stations adaptively through a graph learning module, addressing the dynamic nature of water systems. Additionally, a flood prediction model, LocalFloodNet, combines GNNs with a digital twin simulation tool, enabling interactive flood scenario analysis and prevention strategies. The model was applied to a case study for the city of Terrebonne. Finally, a hybrid model integrating Vision Transformers (ViTs) and LiDAR terrain data is developed for long-term hydrometric prediction, utilizing both static terrain features and dynamic temporal relationships. These models collectively enhance forecasting capabilities across multiple domains, providing more accurate and efficient solutions for traffic and hydrometric challenges
Awakening Evidence: An Ecotouristic Translation of the Letters of Joseph François Mangin
Get PDFThe letters of Franco-American architect Joseph François Mangin weathered the turbulent Age of Revolutions. They include eyewitness accounts of key moments in Haitian and American history, and details of his influential work as an architect in New York City. There are also yet unverified claims that testify to his work on the Erie Canal and drawing the plans for the city of Chambly, and its neighboring canals in Quebec, Canada. The letters testify to the transnational existence of a man who played an active role in designing New World structures and to the debates and conflicts that bore upon such activities at the time.
I will use the opportunity of translating the letters to develop an ecotouristic approach geared toward conservation of the foreign past. One that provides an aesthetic experience rooted in the present, and that privileges conservation by endeavoring to work at the crossroads of history and translation.
The recent foregrounding of time in Translation Studies led me to reconsider it as a variable in research foregrounding space. This led me to reconsider the metaphor of travel developed by Susan Bassnett, in order to ponder the ethics of mediating temporalities, and the potential of time travel as a sub-metaphor to discuss the negotiation thereof. The form employed by the author, the context of the translation itself, led me to revisit Bella Brodzki’s reflections on translation as intergenerational transmission and develop the sub-metaphor of letter-writing, to ponder how one generation answers another.
The untranslatable past manifests in the letters as terms and expressions no longer applicable, expressions specific to the culture and idiom of the time, and idiosyncrasies inherent to a man of that time—all of which lend the text undeniable authenticity. Efforts were made to manifest these elements in a text recast in the present, by featuring loan words, and annotations intended to host the foreign past. Paratexts were added by later generations, when the letters were transcribed, to guide the reader; because the translation is for Joseph François Mangin’s African-American descendants, their reshaping also required careful consideration.
This translation and its commentary emphasize the translator’s role as mediator of temporalities, the intergenerational nature of the endeavor and its potential for agency and conservation. They are intended to contribute to research in the translation of historical texts possessing literary qualities
CECI EST RIEN (sans toi) / This is nothing (without you)
Get PDF(Art) works exploring various types of (artistic) collaborations, all conceptually based on chapters from Neil deGrasse Tyson, Astrophysics for People in a Hurry (New York,W.W. Norton & Company, 2017
Development and Validation of An Indoor Air Quality Assessment System Based on IoT Sensors
Get PDFThis study presents the development and validation of an Arduino-based Internet of Things (IoT) sensor system for continuous and real-time indoor air quality monitoring. Various sensors are examined and integrated into the IoT system to collect data on crucial air pollutants, including carbon dioxide (CO2), particulate matter (PM2.5), nitrogen dioxide (NO2), and volatile organic compounds (VOCs). The collected data is transmitted to an online server and stored in a MySQL database, facilitating efficient data analyses and visualization. Two different validation studies were conducted at Concordia University and Qatar University to assess the system's accuracy and reliability. The Concordia University case study highlights the system's accuracy in measuring CO2, PM2.5, NO2, and VOCs. Employing calibration and modification methods effectively reduces differences to less than 15% compared to well-established commercial monitoring instruments. The Qatar University case further reinforces consistent performance across various parameters and locations and has tested the remote access and management of the developed system. Comparing sensor readings with commercial instruments reveals strong positive correlations and minimal deviations, affirming the integrated device's efficacy in real-time air quality monitoring. Particularly, the developed Arduino-based IoT sensor system offers a user-friendly interface for real-time data visualization through online charts and tables. Additionally incorporating an indoor air quality index model into the developed IoT system allows users for real-time assessment of air cleanliness and to mitigate pollution. In summary, the developed Arduino-based air quality monitoring system presented herein underscores its potential as a cost-effective solution for sustainable environment
Preschoolers’ Responses to Prosocial Opportunities During Naturalistic Interactions with Peers: A Cross-Cultural Comparison
Get PDFThe goal of this study was to better understand similarities and differences in preschool children’s expression of needs and prosocial responsiveness to peers’ needs across two culturally distinct contexts. Preschoolers were observed in a semi-naturalistic design across rural Mexico and urban Canada, wherein they were instructed to build a tower with blocks. Three- to 6-year-olds (N = 306; 48% female) were divided into 64 peer groups. We coded for children’s expression of needs (instrumental, material, or emotional), responses to prosocial opportunities (prosociality, denial, or no response), prosociality without an apparent need (spontaneous prosociality), and types of prosocial behavior (helping, sharing, or comforting). While instrumental and material needs were expressed similarly across both samples, Tzotzil Maya children expressed fewer emotional needs than Canadian children. Failing to respond to others’ needs, followed by denial, were the most frequent need-provoked response in both countries; surprisingly, only 9% of needs received a prosocial response. Though need-provoked prosociality was rare in both cultural contexts, children engaged in considerable spontaneous prosociality which varied as a function of age, gender, and cultural context. Lastly, Canadian more than Tzotzil Maya children denied emotional and instrumental needs (but not material needs). The findings inform how cultural practices may shape the presentation of needs and prosocial responsiveness in peer interactions
Urban Sprawl Metrics (USM) Toolset – User Manual for QGIS - First Edition.
Get PDFThe Urban Sprawl Metrics (USM) Toolset is a geographic information system (GIS) toolset and was developed using Python and C+ languages. The USM Toolset was developed to facilitate the calculation of Weighted Urban Proliferation (WUP) and all components of urban sprawl for landscapes that include built-up areas, e.g., dispersion (DIS), land uptake per person (LUP). The Toolset is straightforward to use. The language of the user interface is English. The Toolset requires three input data:
(1) the binary map of built-up areas (settlements areas and/or solitary buildings), in raster format;
(2) the geometry of reporting unit(s) (e.g., municipalities, districts, or a grid of a certain cell size) in vector format; and
(3) the number of inhabitants and jobs for the reporting unit(s) (this information must be saved by the user in the attribute table of the reporting unit(s) shapefile); and
(4) the share of settleable area for the reporting units to calculate WUPb (optional).
To practice the use of the Toolset, 13 examples are included