Waterloo Research

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Prediction of Bonded Asymmetric Metallic Cross-Tension and Single Lap Shear Joints Using Finite Element Model with Material-Level Adhesive Properties and Cohesive Zone Method
(Elsevier, 2023-01) Ibrahim, Ahmed; Watson, Brock; Jahed, Hamid; Rezaee, Saeid; Royer, Christine; Cronin, Duane
Predictive finite element (FE) models of adhesive joints are needed to enable the design and evaluation of adhesively joined structures, particularly large-scale structures that may be costly to assess experimentally. Although models calibrated to coupon-level tests have provided an important first-step, models based on material-level characterization are needed to enable joint assessment in complex modes of loading. In the present study, a structural epoxy adhesive was characterized using rigid double cantilever (Mode I) and bonded shear (Mode II) specimens to provide material-level input properties. Three single-lap shear (SLJ) and seven cross-tension (CT) specimen configurations were fabricated with aluminum and steel sheet materials. The specimens included symmetrical (the same adherend material and thickness) and asymmetrical (dissimilar adherend material or unequal thickness) configurations, with three loading angles (0°, 45°, 90°) for the CT specimens. Finite element models of the SLJ and CT specimens were developed using Cohesive Zone Modeling for the adhesive, with properties determined from the Mode I and Mode II characterization tests. The FE models of the SLJ and CT test specimens predicted the peak load within an average difference of 2%–19%. The joint strength varied between different test configurations, owing to adherend deformation, load eccentricity and mixed-mode loading. Importantly, the model parameters were not calibrated to the SLJ and CT tests. The FE models were able to predict joint response for varying test specimen geometry, adherend thickness, adherend material, and modes of loading.
La fabrique de la traduction, un cadrage queer : Michel Tremblay traduit par John Van Burek et Bill Glassco
(Erudit, 2020-05-01) Nolette, Nicole; Louër, Dominique
Cet article porte sur la traduction vers l’anglais de la pièce de théâtre Hosanna de Michel Tremblay par John Van Burek et Bill Glassco, réalisée à Toronto au milieu des années 1970. En entrant dans la fabrique de la traduction, nous avançons l’hypothèse que, des deux éléments linguistico-culturels marquants pour les publics d’Hosanna – le joual et le sujet queer –, le second a été peu privilégié dans le travail des traducteurs. Nous abordons le carrefour entre queer studies, traduction des sociolectes et génétique de la traduction pour montrer que les traducteurs ne s’attardent pas particulièrement aux aspects queer de la pièce, mais cherchent surtout à produire, au fil des versions, une langue pour les personnages de Tremblay.
Les orbites multiples de Satellite Théâtre : théâtre local et internationalisation du théâtre
(Erudit, 2021-12-08) Cormier, Pénélope; Nolette, Nicole
Cofondée par l’Acadien Mathieu Chouinard et le Québécois Marc-André Charron, la compagnie Satellite Théâtre est reconnue pour ses activités de formation, de création et de diffusion dans les marchés du théâtre à l’échelle locale, nationale et internationale. Nous nous basons sur une méthodologie issue de la sociologie de l’art pour dresser, à partir d’entretiens avec les cofondateurs, la carte des alliances stratégiques et des réseaux qui font le succès de la compagnie, depuis son établissement à Montréal en 2009 et pour suivre l’impact de son déménagement à Moncton en 2016. Il transparaît que l’innovation de Satellite Théâtre dans le milieu du théâtre acadien est de solliciter à la fois les réseaux (locaux et nationaux) des milieux artistiques en situation minoritaire, ainsi que les réseaux locaux (souvent créés par les activités de formation et d’accompagnement de la relève de la compagnie), nationaux et internationaux partageant le même langage théâtral, basé sur l’échange interculturel et le théâtre gestuel ou physique
Surtitling and the new networks of theatre translation in Toronto
(Taylor & Francis, 2022-09-20) Nolette, Nicole
This article deals with human and non-human agents of surtitling in Toronto and beyond. After its emergence at the opera in Toronto, surtitling travelled to the theatre, and to other parts of French-speaking Canada, North America and Europe. Based on interviews with theatre surtitlers and on their archived materials, this article tracks the invention, growth, social acceptance, standardization, and stagnation of surtitling technologies in Toronto. Three relational aspects of the process of surtitling as a medium of theatre translation are investigated to understand its effects on translators and translations now: the division of labour (or lack thereof) from the opera to the theatre; the standardization of the practice; and the intergenerational transmission of competence through informal training.
La médiation culturelle numérique et le théâtre francophone au Canada en début de pandémie
(Erudit, 2023-12-12) Nolette, Nicole; Giguère, Frédéric
Des efforts majeurs ont été déployés par les organismes artistiques pour faire de la médiation culturelle une approche privilégiée du développement culturel des francophonies minoritaires du Canada. Cet article relate les résultats d’une enquête quantitative et qualitative sur l’usage du numérique dans les activités de médiation culturelle des compagnies de théâtre francophones du Canada à l’été 2020. Il met à l’épreuve certains outils développés au Laboratoire de recherche sur les publics de la culture de l’Université du Québec à Trois-Rivières pour une enquête similaire sur les dispositifs numériques de médiation culturelle mis en place dans les arts de la scène (cirque, danse, théâtre) au Québec. L’étude cherche à saisir l’envergure du virage numérique qui s’est opéré dans les compagnies de théâtre francophones du Canada et à comprendre la particularité de la médiation culturelle numérique de ces institutions de langue officielle en milieu minoritaire, notamment le surtitrage et l’éducation.
Ontario Climate Risk: Workshop Report
(University of Waterloo, Waterloo Climate Institute; University of Toronto, Toronto Client Observatory., 2025-09-25) Costa, Rodrigo; Soden, Robert
Despite having the country's largest economy, population, and number of universities with world-class expertise on the topic, Ontario lacks a hub for sharing information and best practices, and fostering connections between those working to address climate risk. There is a need for rigorous inquiry into localized climate impacts, including the potential for increased frequency and intensity of heatwaves, disruptions in water availability, and impacts on the Great Lakes region ecosystems. The significant expertise amongst academics and other researchers across the region regarding the complex dynamics between these factors will be necessary for devising effective and equitable mitigation and adaptation strategies. Identifying and addressing these gaps in our knowledge is paramount for developing region-specific strategies to mitigate and adapt to climate change, thereby contributing to the overall resilience and sustainability of Ontario's communities. In this context, the Ontario Climate Risk Workshop, held on October 30-31, 2024, brought together participants from academia, public and private sectors, non-governmental organizations, Indigenous leaders, elected officials, and representatives of the general public to share knowledge, discuss existing initiatives, and co-create a research agenda for addressing climate risk in the province. The event was structured around eight thematic sessions, each of which is documented in this report. Within each session, participants examined and discussed existing resources and barriers relevant to addressing climate risks associated with the respective theme. These proceedings provide an overview of the discussions for each session and were co-developed by our research team along with the respective session leads.
Assessment of Thorax Response and Impact Location Dependence for Behind Armor Blunt Trauma
(Blast and Conflict Injury Conference, 2024-07-11) Bustamante, Michael C.; Cronin, Duane S.
Behind Armor Blunt Trauma (BABT) injuries can result from non-perforating ballistic impacts on thoracic armor. At present, the evaluation of soft armor performance involves subjecting it to various impacts, including shot-to-edge and shot-to-shot tests. Clay backing is utilized to measure the Back Face Deformation (BFD), where 44 mm is often used as a threshold. In a recent study, the correlation between BFDs and injuries was investigated using a computational human body model (HBM) to gain insights into injury tolerance, and to re-create real-world BABT cases that resulted in good, but conservative, injury predictions relative to the medical reports. It was noted that impacts occurred at various locations on protective body armour, but this was not considered in contemporary injury thresholds. In this study, a thorax model, enhanced for high-rate deformation, was used to assess soft armor BABT for varying impact locations and BFDs. Twenty-four cases were simulated for three severities and applied to the thorax in a grid pattern covering low and high compliance regions spanning the sternum, ribs, and costal cartilage. Whole thoracic and locationally segregated injury risk curves (IRCs) were calculated for deformation- and kinetic-based metrics. Then the variability and prediction accuracy of the methods were evaluated using receiver-operating characteristic (ROC) area-under-the-curve (AUC) analysis. The number of rib fractures, percent pulmonary contusion by volume, and corresponding injury rank, increased with increasing BFD. It was found that deformation-based IRCs generally had lesser variability and better accuracy than the kinetic-based IRCs. When impacts of like locations were grouped, it was found that location had a marked effect on the deformation-based IRCs, generally decreasing variability and increasing accuracy relative to the whole thorax IRC, suggesting that different regions of the thorax may have varying deformation tolerance levels.
Optimal Demand Response for Distribution Feeders With Existing Smart Loads
(Institute of Electrical and Electronics Engineers (IEEE), 2017-03-23) Mosaddegh, Abolfazl; Canizares, Claudio A.; Bhattacharya, Kankar
Load characteristics play an important role in distribution systems, which are traditionally designed to supply peak load; hence, decreasing this peak can considerably reduce overall grid costs. Basic components of smart grids such as smart meters allow two-way communication between the utilities and customers; in this context, controllable smart loads are being introduced, which allow developing and implementing energy management systems for customers and distribution feeders. Therefore, this paper studies the impact of existing smart loads, in particular Peaksaver PLUS (PS+) loads in ON, Canada, to reduce summer peak loads for distribution feeders. A neural network model of controllable loads is developed and integrated into an unbalanced distribution optimal power flow (DOPF) model to optimally control tap changers and switched capacitors, as well as sent signals to programmable thermostats of air conditioners in residential buildings, in particular those associated with the PS+ program. The developed integrated DOPF is tested and validated using a practical system, demonstrating the benefits of using existing controllable loads to optimally operate distribution feeders.
Brain Material Properties and Integration of Arachnoid Complex Improve Impact Response for Human Head Finite Element Model
(Springer, 2024-01-13) Rycman, Aleksander; Bustamante, Michael; Cronin, Duane S.
Finite element head models offer great potential to study brain-related injuries; however, at present may be limited by geometric and material property simplifications required for continuum-level human body models. Specifically, the mechanical properties of the brain tissues are often represented with simplified linear viscoelastic models, or the material properties have been optimized to specific impact cases. In addition, anatomical structures such as the arachnoid complex have been omitted or implemented in a simple lumped manner. Recent material test data for four brain regions at three strain rates in three modes of loading (tension, compression, and shear) was used to fit material parameters for a hyper-viscoelastic constitutive model. The material model was implemented in a contemporary detailed head finite element model. A detailed representation of the arachnoid trabeculae was implemented with mechanical properties based on experimental data. The enhanced head model was assessed by re-creating 11 ex-vivo head impact scenarios and comparing the simulation results with experimental data. The hyper-viscoelastic model faithfully captured mechanical properties of the brain tissue in three modes of loading and multiple strain rates. The enhanced head model showed a high level of biofidelity in all re-created impacts in part due to the improved brain-skull interface associated with implementation of the arachnoid trabeculae. The enhanced head model provides an improved predictive capability with material properties based on tissue level data and is positioned to investigate head injury and tissue damage in the future.
Navigating food futures post-disaster: the intersectional politics of race, gender, disability and access
(Informa UK, 2025-10-01) Diaz, Ileana I.
A historically devastating series of climatic events in September 2017 transformed lives in Puerto Rico and its diaspora. The impacts of Hurricanes Irma and Maria ruptured the functionality of lifeways in unprecedented forms. The events also characterize the longest disaster response muddle in the history of the United States. This focused case study investigates the ways that individuals navigate their island food system in a post-disaster context. It explores the political, social and economic circumstances which inform various experiences of food insecurity, hunger, gendered vulnerabilities, disability and the role that layered structural inequity plays in producing unequal access to food. Based on news media, photographic analysis and in-depth interviews conducted with those who lived through both hurricanes, an evidence-informed intersectional analysis is produced. Scaffolding the research conceptually through an intersectionality and Afro-diasporic futures epistemology, this paper contributes a geographical and feminist analysis to the study of disasters in relation to food insecurity. Markedly, people living with disabilities and women participants reported increased challenges to disaster recovery and resilience. Parents were found to be the most food insecure. Research findings show that gender, race, disability and income play a pivotal role in shaping food access and long-term wellbeing in post-disaster contexts. -----
Self-assembled manganese phthalocyanine nanoparticles with enhanced peroxidase-like activity for anti-tumor therapy Research Article Published: 29 September 2021
(2021-09-29) Wang, Jinghan; Gao, Shanqing; Wang, Xiao; Zhang, Haozhen; Ren, Xitong; Liu, Juewen; Bai, Feng
The use of functional nanoparticles as peroxidase-like (POD-like) catalyst has recently become a focus of research in cancer therapy. Phthalocyanine is a macrocyclic conjugated metal ligand, which is expected to achieve a high POD-like catalytic activity, generating free radicals and inhibiting the proliferation of cancer cells. In this paper, we synthesized phthalocyanine nanocrystals with different structures through noncovalent self-assembly confined within micro-emulsion droplets, and manganese phthalocyanine (MnPc) possessing a metal-N-C active center was used as the building block. These nano-assemblies exhibit shape-dependent POD-like catalytic activities, because the emulsifier and MnPc co-mixed assembly reduced the close packing between MnPc molecules and exposed more active sites. The assembly had a water-dispersed nanostructure, which is conducive to accumulation at tumor sites through the enhanced permeability and retention effect (EPR). Because of a highly efficient microenvironmental response, the assembly showed higher catalytic activity only emerged under the acidic tumor-like microenvironment, but caused less damage to normal tissues in biomedical applications. In vivo and in vitro catalytic therapy tests showed excellent anti-tumor effects. This work explored a new way for the application of metal-organic macromolecules such as MnPc as nanozymes for catalytic tumor therapy.
Hypothesis Testing of Multivariate Biomechanical Responses using Statistical Parametric Mapping and Arc-Length Re-Parameterization
(Springer Nature, 2025-07-14) Hartlen, Devon C.; Cronin, Duane S.
Detection of differences between experimental biomechanical data sets is critical to quantify effects and their significance. Many forms of biomechanical data are continuous and multivariate in nature, yet contemporary statistical analysis and hypothesis testing most often utilize single-value scalar metrics. However, reducing continuous responses to single-value scalar metrics can introduce bias and eliminate much of the physical context of a response. This study proposes a methodology to perform hypothesis testing directly on continuous multivariate experimental data sets. The methodology couples arc-length re-parameterization with statistical parametric mapping (SPM) to provide a general framework that can be applied to many of the response types found in biomechanics, including sets of responses that do not terminate at a common coordinate or are hysteretic, such as load-unload data. The arc-length-based SPM methodology was applied to three literature data sets representing a cross-section of the types of responses encountered in biomechanics. In each case, the arc-length-based SPM methodology produced results that agreed with contemporary statistical techniques while providing quantification and identification of statistically significant differences between the data sets. The proposed method provided important contextual information and a deeper understanding of the underlying behaviour of a dataset that would otherwise be missed using contemporary single-value scalar metric statistical techniques, such as highlighting specific response features that drive differences between datasets.
Nucleobase, nucleoside, nucleotide, and oligonucleotide coordinated metal ions for sensing and biomedicine applications
(Springer Nature, 2021-04-19) Zhou, Jiaojiao; Han, Heyou; Liu, Juewen
Metal ions play critical roles in chemical, biological, and environmental processes. Various biomolecules have the ability to coordinate with metal ions and form various materials. Nucleobases, nucleosides, and nucleotides, as the essential components of DNA, have emerged as a useful building block for the construction of functional nanomaterials. In recent years, DNA oligonucleotides have also been used for this purpose. We herein review the strategies for the synthesis of soft nanomaterials through the assembly of nucleotides (or DNA) and metal ions to yield various nanoparticles, fibers, and hydrogels. Such coordination methods are simple to operate and can be carried out under ambient conditions. The luminescent, catalytic, and molecular recognition properties of these coordination materials are described with representative recent examples. Their applications ranging from biosensing, enzyme encapsulation, catalysis, templated shell growth to cancer therapy are highlighted. Finally, challenges of this field and future perspectives are discussed.
Critical evaluation of aptamer binding for biosensor designs
(Elsevier, 2021-11-13) Zhao, Yichen; Yavari, Kayvan; Liu, Juewen
Over the last three decades, numerous aptamer-based biosensors have been reported. The basis of these sensors is the selective binding of target analytes by aptamers. In the last few years, a number of papers have been published questioning the binding ability of some popular aptamers such as those documented for As(III), ampicillin, chloramphenicol, isocarbophos, phorate and dopamine. In this article, these papers are reviewed, and the binding assays are described, which may provide possible reasons for obtaining false positive aptamers. Additionally, relevant aptamer selection methods and typical characterization steps are described. It is found that for small molecular targets, using an immobilized library might result in better aptamers. Furthermore, the importance of carefully designed controls to ensure the quality of binding assays is discussed, especially in the case of mutated nonbinding aptamers. Only then, with fully validated aptamers, can subsequent biosensor design bring about meaningful results.
Deployment of functional DNA-based biosensors for environmental water analysis
(Elsevier, 2022-04-14) Zhao, Yichen; Yavari, Kayvan; Wang, Yihao; Pi, Kunfu; Van Cappellen, Philippe; Liu, Juewen
Various functional DNA molecules have been used for the detection of environmental contaminants in water, but their practical applications have been limited. To address this gap, this review highlights the efforts to develop field-deployable water quality biosensors. The biosensor devices include microfluidic, lateral flow and paper-based devices, and other novel ideas such as the conversion of glucometers for the detection of environmental analytes. In addition, we also review DNA-functionalized hydrogels and their use in diffusive gradients in thin films (DGT) devices. We classify the sensors into one-step and two-step assays and discuss their practical implications. While the review is focused on works reported in the last five years, some classic early works are cited as well. Overall, most of the existing work only tested spiked water samples. Future work needs to shift to real environmental samples and the comparison of DNA-based sensors to standard analytical methods.
Signaling Kinetics of DNA and Aptamer Biosensors Revealing Graphene Oxide Surface Heterogeneity
(Springer Nature, 2021-12-16) Huang, Po-Jung Jimmy; Liu, Juewen
Adsorption of fluorescently labeled DNA and aptamer probes to graphene oxide (GO) has been one of the most popular methods for developing biosensors. In the presence of target analytes, the quenched fluorescence would recover. In this work, we followed the kinetics of the reactions and found that the fluorescence would eventually drop after an initial increase, and this was attributed to the re-adsorption of the desorbed probe DNA molecules. Both a DNA probe and an aptamer for adenosine were used. This re-adsorption was attributed to the surface heterogeneity of GO, and the DNA probes desorbed from relatively weaker binding sites were re-adsorbed on the stronger binding sites. This re-adsorption can be avoided by extensive washing the samples, and also by blocking the GO surface or by heating. This fundamental understanding is important for achieving a stable signal of such biosensors.
Adsorption of Linear and Spherical DNA Oligonucleotides onto Microplastics
(American Chemical Society, 2022-01-30) Zandieh, Mohamad; Patel, Kshiti; Liu, Juewen
Microplastic pollution of water and food chains can endanger human health. It has been reported that environmental DNA can be carried by microplastics and spread into the ecosystem. To better comprehend the interactions between microplastics and DNA, we herein investigated the adsorption of DNA oligonucleotides on a few important microplastics. The microplastics were prepared using common plastic objects made of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), composite of PS/PVC, and polyethylene terephthalate (PET). The effect of environmentally abundant metal ions such as Na+, Mg2+, and Ca2+ on the adsorption was also studied. Among the microplastics, PET and PS had the highest efficiency for the adsorption of linear DNA, likely due to the interactions provided by their aromatic rings. The study of DNA desorption from PET revealed the important role of hydrogen bonding and metal-mediated adsorption, while van der Waals force and hydrophobic interactions were also involved in the adsorption mechanism. The adsorption of spherical DNA (SNA) made of a high density of DNA coated on gold nanoparticles (AuNPs) was also studied, where the adsorption affinity order was found to be PET > PS/PVC > PS. Moreover, a tighter DNA adsorption was achieved in the presence of Ca2+ and Mg2+ compared to Na+.
Selection of Aptamers for Sensing Caffeine and Discrimination of Its Three Single Demethylated Analogues
(American Chemical Society, 2022-02-10) Huang, Po-Jung Jimmy; Liu, Juewen
With the growing consumption of caffeine-containing beverages, detection of caffeine has become an important biomedical, bioanalytical, and environmental topic. We herein isolated four high-quality aptamers for caffeine with dissociation constants ranging from 2.2 to 14.6 μM as characterized using isothermal titration calorimetry. Different binding patterns were obtained for the three single demethylated analogues: theobromine, theophylline, and paraxanthine, highlighting the effect of the molecular symmetry of the arrangement of the three methyl groups in caffeine. A structure-switching fluorescent sensor was designed showing a detection limit of 1.2 μM caffeine, which reflected the labeled caffeine concentration within 6.1% difference for eight commercial beverages. In 20% human serum, a detection limit of 4.0 μM caffeine was achieved. With the four aptamer sensors forming an array, caffeine and the three analogues were well separated from nine other closely related molecules.
Homogeneous assays for aptamer-based ethanolamine sensing: no indication of target binding
(Royal Society of Chemistry, 2022-02-11) Ding, Yuzhe; Liu, Xun; Huang, Po-Jung Jimmy; Liu, Juewen
Ethanolamine is an important analyte for environmental chemistry and biological sciences. A few DNA aptamers were previously reported for binding ethanolamine with a dissociation constant (Kd) as low as 9.6 nM. However, most of the previous binding assays and sensing work used either immobilized ethanolamine or immobilized aptamers. In this work, we studied three previously reported DNA sequences, two of which were supposed to bind ethanolamine while the other could not bind. Isothermal titration calorimetry revealed no binding for any of these sequences. In addition, due to their guanine-rich sequences, thioflavin T was used as a probe. Little fluorescence change was observed with up to 1 μM ethanolamine. Responses within the millimolar range of ethanolamine were attributed to the general fluorescence quenching effect of ethanolamine instead of aptamer binding. Finally, after studying the adsorption of ethanolamine to gold nanoparticles (AuNPs), we confirmed the feasibility of using AuNPs as a probe when the concentration of ethanolamine was below 0.1 mM. However, no indication of specific aptamer binding was observed by comparing the three DNA sequences for their color changing trends. This work articulates the importance of careful homogeneous binding assays using free target molecules.
Adsorption of DNA Oligonucleotides by Self-Assembled Metalloporphyrin Nanomaterials
(American Chemical Society, 2022-03-08) Wang, Jinghan; Wang, Zhen; Huang, Po-Jung Jimmy; Bai, Feng; Liu, Juewen
Porphyrin assemblies have controllable morphology, high biocompatibility, and good optical properties and were widely used in biomedical diagnosis and treatment. With the development of DNA biotechnology, combining DNA with porphyrin assemblies can broaden the biological applications of porphyrins. Porphyrin assemblies can serve as nanocarriers for DNA, although the fundamental interactions between them are not well understood. In this work, zinc meso-tetra(4-pyridyl)porphyrin (ZnTPyP) assemblies were prepared in the presence of various surfactants and at different pH values, yielding a variety of aggregation forms. Among them, the hexagonal stacking form exposes more pyridine substituents, and the hydrogen bonding force between the substituents and the DNA bases allows the DNA to be quickly adsorbed on the surface of the assemblies. The effects of DNA sequence and length were systematically tested. In particular, the adsorption of duplex DNA was less efficient compared to the adsorption of single-stranded DNA. This fundamental study is useful for the further combination of DNA and porphyrin assemblies to prepare new functional hybrid nanomaterials.

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