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Development and Testing of Novel Soft Sleeve Actuators
No full textAs societies confront the challenges of aging populations and the growing prevalence of neurological and musculoskeletal disorders, the demand for mobility-assistive technologies that restore limb control or enhance physical abilities has become increasingly urgent. Many existing assistive devices rely on incompatible technological solutions, rendering them impractical and uncomfortable for users. This research seeks to address these limitations by advancing the development of soft and wearable actuators, which offer significant potential for creating functional and user-friendly mobility-assistive devices.
Traditional soft actuators are valued for their adaptability and compliance but face significant constraints in generating and transferring forces to the user. These limitations often necessitate complex interface mechanisms, which detract from both device effectiveness and user comfort. To overcome these challenges, this study introduces an innovative soft sleeve actuator design and presents three novel actuator models capable of performing linear, bending, and twisting motions while generating the required mechanical forces and moments. Additionally, the study unveils the Omnidirectional actuator, a breakthrough design that combines the motions of the original models.
The newly developed actuators feature an intricate design that requires a custom fused deposition manufacturing process. This tailored approach ensures precise production while effectively addressing the challenge of air leakage, a problem to resolve with traditional manufacturing methods. Moreover, customized testing setups are developed to assess the actuators' performance and explore how variations in geometric parameters and material properties affect the actuator’s ability to generate kinematic and kinetic outputs.
In summary, this research introduces a significant innovation to soft actuation, enabling the development of wearable devices capable of executing complex motions without relying on complex interface mechanisms. By achieving superior kinematic and kinetic performance, these advancements contribute significantly to the evolution of assistive mobility technologies, paving the way for more effective and user-centric solution
Gaps in the Ottawa Statement on the Ethical Design and Conduct of Cluster Randomized Trials: a citation analysis reveals a need for updated ethics guidelines
No full textAbstract Background Although commonly used to evaluate health interventions, cluster randomized trials raise difficult ethical issues. Recognizing this, the Ottawa Statement on the Ethical Design and Conduct of Cluster Randomized Trials, published in 2012, provides 15 recommendations to address ethical issues across seven domains. But due to several developments in the design and implementation of cluster randomized trials, there are new issues requiring guidance. To inform the forthcoming update of the Ottawa Statement, we aimed to identify any gaps in the Ottawa Statement discussed within the literature. Methods We searched Google Scholar, Scopus, and Web of Science using the ‘cited by’ function on 11 November 2022.We included all types of publications, including articles, book chapters, commentaries, editorials, ethics guidelines, theses and trial-related publications (i.e., primary reports, protocols, and secondary analyses), that cited and engaged with the Ottawa Statement, the Ottawa Statement précis, or one or more of its four background papers. Data were extracted by four reviewers working in rotating pairs. Reviewers captured relevant text verbatim and recorded whether it reflected a gap relating to one or more of the Ottawa Statement domains. Using a thematic analysis approach, semantic coding was used to summarize the content of the data into distinct gaps within the Ottawa Statement domains, which was subsequently expanded in an inductive manner through discussion. Results The qualitative analysis of the text from 53 articles resulted in the identification of 24 distinct gaps in the Ottawa Statement: 4 gaps about justifying the cluster randomized design; 2 gaps about research ethics committee review; 3 gaps about identifying research participants; 4 gaps about obtaining informed consent; 3 gaps about gatekepeers; 6 gaps about assessing benefits and harms; 1 gap about protecting vulnerable participants; and 1 gap about equity-related issues in cluster randomized trials. Conclusion Identifying 24 gaps reveals a need to update the Ottawa Statement. Alongside additional gaps identified in ongoing empirical work and through engagement with our patient and public partners, the gaps identified through this citation analysis should be considered in the forthcoming Ottawa Statement update
Spinal dI3 Circuits in the Modulation of Skilled and Corrective Locomotor Behaviours
No full textMany spinal neurons integrate sensory input to adapt a wide array of movements. Prior research has shown that spinal dorsal interneuron 3 (dI3) neurons receive cutaneous and proprioceptive sensory input and that they project to motor circuits, most notably through excitation of motoneurons. We sought to better delineate the spinal circuits within which dI3 neurons operated. To reach this objective, we tested motor performance of transgenic mice where dI3s could be chemogenetically silenced by the DREADD receptor, hM4Di. Chemogenetic inhibition of dI3s was concomitant with drug treatments that putatively inhibited (mecamylamine) or enhanced (L-acetyl carnitine) recurrent motoneuron excitation of central targets such as Renshaw cells. In addition to these two cholinergic modulators, saline was also administered as a separate treatment to act as a control. Each of these three separate treatments were administered in combination with either JHU37160, an hM4Di agonist to silence dI3s, or a saline control to maintain dI3 activity. These mice were then tested on three behavioural tasks.
For performance related to fine motor control, balance, and coordination, mice were tested on a vibrating balance beam and horizontal ladder walking task. In both ladder and beam tasks, mice demonstrated an up to three-fold increase in the incidence of foot falls after dI3 inhibition with either L-acetyl carnitine or saline as a combined treatment. We also observed two- to three-fold increases in footfalls on the ladder and beam after mecamylamine administration, an antagonist of Renshaw cell excitation, in combination with dI3 silencing but also without dI3 silencing. Interestingly, ladder and beam tasks performed after a combined treatment that silenced both dI3s and Renshaw cell excitation did not appear to have a compounding effect in the observed motor deficits on these apparatuses; the increase in foot falls remained two to three-fold higher when comparing trials with and without dI3 silencing as combined with mecamylamine. Overall, we observed an increase in motor deficits and difficulty when crossing both the ladder and beam after dI3 silencing and mecamylamine administration.
Additionally, mice were also tested on a treadmill apparatus wherein the hindlimb paw was either mechanically or electrically perturbed to attempt to trigger the stumbling corrective reaction. With L-acetyl carnitine and saline trials, dI3 silencing resulted in a significant reduction in the peak step height during a stumbling corrective response in comparison to trials without dI3 silencing. Conversely, the effects of dI3 inhibition and mecamylamine administration yielded a similar trend to the previous behavioural task, wherein step heights during the peak of the reflex were significantly reduced after dI3 silencing and/or mecamylamine administration compared to saline controls but were not statistically different when comparing trials with and without dI3 silencing if mecamylamine was also administered. While this reflex was not completely abolished, we observed significantly increased instances of failed attempts to clear the perturbation resulting in dragging and a significant blunting of the stumbling corrective response with both mecamylamine administration and dI3 silencing, both separately and together.
Overall, our findings support the hypothesis that dI3s are involved in the activation of the stumbling corrective response, wherein proprioceptive and cutaneous signals may be used to modulate the activation of muscles during locomotion. While there remains much to be understood about dI3 spinal circuits, it appears that a lack of dI3 signaling inhibits skilled locomotor behaviours. Our results suggest that dI3s are more involved in skilled and corrective motor behaviours than previously understood, as we suggest that Renshaw cells and dI3s may operate together within a type of neural comparator module to actively monitor sensory signals and rapidly adjust motor outputs. Our experiments begin to identify the spinal circuits within which dI3s operate to shape motor activity
Influence of Vortical Structure on Flame Acceleration in Hydrogen-Air, Methane-Air, and Hydrogen-Methane/Air Blend
No full textFollowing the ignition of a flame in a duct, the characteristics of the flame-driven flow play an important role in the propagation and acceleration of the flame. When bluff body obstacles are present in the duct, vortical structures are formed in the flow downstream of the obstacle. The subsequent interaction of the flame with these vortices is believed to generate substantial flame deformation and acceleration. In the present study, we investigate the deformation of the flame resulting from its interaction with these vortices. The experiments were performed in stoichiometric hydrogen-air, methane-air, and an equimolar blend of hydrogen and methane at ambient conditions.
Experiments were conducted in a thin, rectangular shock tube, with a rectangular obstacle positioned within it. The shock tube was initially filled with the mixtures at atmospheric pressure. A planar flame was then ignited at the closed end of the shock tube using a long wire ignition technique and propagated toward the open end. The high Reynolds number of the flow ahead of the flame resulted in flow separation at the leading edge of the obstacle, forming a vortical structure. Following the entrainment of the flame into the vortex, the flame surface area increased, resulting in the acceleration of the flame-driven flow. The evolution of the flame was visualized using high-speed direct shadowgraph and Z-type Schlieren. The pressure evolution was measured using pressure transducers placed along the top and bottom walls of the shock tube.
The measured evolution of the flame speed and overpressure inside the shock tube highlights the higher reactivity and flame acceleration of the hydrogen-air flame compared to the flames propagating in methane-air and equimolar hydrogen-methane blend with air. To facilitate a better comparison of the propagating flames, the pressure and velocity measurements obtained from the experiments are expressed in a non-dimensional form. This approach effectively eliminates the dependence on the distinct laminar burning velocities of each mixture. Hydrogen, with its characteristic thin flame structure, is less affected by the turbulent features formed behind the obstacle than mixtures containing methane. These mixtures show a much larger increase in flame surface area and wrinkled structures because their flame times are longer than the characteristic time of the vortical structure. Consequently, they exhibit a higher normalized pressure peak compared to the hydrogen mixture. To compare the normalized overpressure between methane-air and equimolar mixtures, in the equimolar flame, due to the relatively shorter flame time and an increase in the concentration of hydrogen in the positive curvatures of the flame front, the amount of local quenching induced by turbulence is reduced. As a result, the equimolar mixture records a higher normalized pressure than the methane mixture.
In the second set of experiments, two parallel mirrors positioned at a 45-degree angle are installed on the top and bottom walls of the shock tube to visualize the third dimension of the flame propagating along the shock tube. This method is applied for the first time in this study, and the shadowgraph technique is used to capture 3D flame propagation. It is observed that the mixtures with a Lewis number below unity (hydrogen and the equimolar mixtures) show more 3D effects compared to methane. These two flames tend to incline along the width of the shock tube, and this behavior intensified when the flames got entrained into the vortical structures and accelerated
Blood Flow in Microcirculation: Investigating the Cell-Free Layer with Capillary Microchannels
No full textBlood flow in the microcirculation is governed by complex interactions between red blood cells (RBCs) and plasma, resulting in distinct rheological behaviours that differ from bulk flow properties. A key microvascular phenomenon is the cell-free layer (CFL) - a plasma-rich region near vessel walls that plays a critical role in vascular resistance, oxygen transport, and nutrient exchange. Despite its physiological significance, the primary mechanisms driving CFL formation remain debated, and accurate measurement techniques are essential for a comprehensive understanding of this phenomenon. This study aims to investigate how channel size (25 and 50 µm), hematocrit, and suspension medium influence non-Newtonian properties and CFL formation. It also seeks to evaluate the suitability of different rheological models in capturing CFL behaviour and compare measurement techniques for CFL quantification. Microfluidic experiments were conducted using blood suspensions under controlled flow conditions. Various rheological models - including the Newtonian, Power Law, and Carreau Models - were analyzed to determine their effectiveness in predicting CFL behaviour. The Double-Parameter Power (DPP) fit was also assessed for velocity profile characterization. CFL thickness was measured using both optical imaging and hydrodynamic methods, providing comparative insights into their accuracy and reliability. The results indicate that the Core-Plasma Model, developed in this work, best captures the two-phase nature of blood flow by distinguishing the RBC-rich core from the plasma layer. Optical imaging was found to be the most reliable and accurate method for CFL measurement, while hydrodynamic methods offered indirect but complementary insights. Additionally, shear rate gradients were identified as a dominant factor in CFL formation. These findings enhance the understanding of CFL dynamics in microcirculation, providing a more accurate framework for modelling blood flow under physiologically relevant conditions
Advancing equity in healthcare systems: understanding implicit bias and infant mortality
No full textAbstract Using data from the Centers for Disease Control and Prevention’s Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) and Project Implicit, this study examined whether anti-Black implicit racial biases predict infant mortality for Black Americans. We examined state-level mean Black-White Implicit Association Test (BW-IAT) Bias Scores and controlled for explicit bias scores and White infant mortality rates for over 1.7 million American participants across ten different ethnoracial groups between 2018–2020. Hierarchical linear regressions determined state-level anti-Black implicit bias significantly predicted state-level Black infant mortality rates, above and beyond explicit bias and White infant mortality, in 2018 (b = .32, t(34) = 2.09, p < .05), 2019 (b = .30, t(34) = 2.09, p < .05), and 2020 (b = .32, t(34) = 2.18, p < .05). State-level anti-Black implicit bias also explained a significant proportion of variance in state-level infant mortality rates, in 2018 (R2 = 0.30, F(3, 35) = 4.89, p < 0.01), 2019 (R2 = .33, F(3, 36) = 5.95, p < .01), and 2020 (R2 = .39, F(3, 35) = 7.58, p < .001). Also, among healthcare professionals, there are similar levels of implicit biases compared to the general American population. Findings suggest that implicit racial bias is a risk factor for Black infant mortality. These findings also point to the ethical challenge implicit biases pose to equitable decision-making and patient-provider relationships in healthcare. By integrating these insights into interdisciplinary discussions, this study provides supporting data for systemic reforms and anti-bias training to create a healthcare system grounded in fairness and equity
A Multi-Modal Assessment of Support Use Among Multiple Sclerosis Family Caregivers in Canada
No full textFamily caregivers of individuals living with multiple sclerosis (MS) are essential to the wellbeing and independence of their care recipients. Despite the prevalence and importance of MS family caregivers, many struggle to maintain their wellbeing while also meeting demands for care. Most of the MS caregiving literature has focused on negative outcomes associated with the caregiving role; however, MS family caregivers also report benefits to caregiving that remain poorly understood. Resources are deeply implicated in salutogenic paradigms of health and could be used promote the wellbeing of caregivers through the creation of supportive environments. However, little is known about the current state of supports for MS family caregivers in Canada. Thus, this dissertation sought to establish a salutogenic paradigm for supporting MS family caregivers by identifying current caregiving resources and resource use dynamics. Included in this dissertation are three studies to achieve this goal.
The first study of this dissertation examined the current landscape of caregiving resources in Canada as experience by family caregivers via an environmental scan of digital supports. This study identified mostly informational resources authored by provincial caregiving organizations. Findings highlighted a lack of diversity in the target audiences of current digital caregiving resources and a dearth of interactive and practical supports.
The second study of this dissertation examined the content and feature priorities for a novel digital resource among MS family caregivers and service providers via online survey. Participants prioritized the ease of use of a future digital resource as a top priority. A wide range of content priorities were identified, with the most frequent being information on MS and its treatment. Findings emphasized the potential of a digital resource to provide a range of support to MS family caregivers and centred the importance of user testing to ensure the usability and uptake of the resource.
The third study of this dissertation presented in Chapters 4 and 5, investigated current support structures and support use dynamics of MS family caregivers via online survey and semi-structured interviews. The content of support structures reported by caregivers highlighted the importance of natural support networks, including the care recipient. Levels of resilience and neuroticism were associated with the size of support structures. Through interviews, caregivers identified that cycles of resilience were mediated by supports and reported key facilitators and barriers to support use. Findings demonstrated the complex decision-making processes behind support use and highlighted the need for flexible support that can accommodate variable support needs and preferences of MS family caregivers.
Collectively, the findings of this dissertation operationalize a salutogenic paradigm for supporting MS family caregivers. Key recommendations are given to create supportive environments for caregivers and optimize their wellbeing. Improvements in access to respite care and financial support, better visibility of digital resources, and bolstering natural support networks may all be valuable strategies to improving the wellbeing of MS family caregivers in Canada
Fibro/Adipogenic Progenitor-Derived Follistatin-Like 1 Expression is Reduced by Irradiation to Regulate Fibro/Adipogenic Progenitor Fate Decisions
No full textIntroduction: Five-year cancer survivorship is increasing; however, the long-term effects of treatments are detrimental to skeletal muscle. We have found that fibro-adipogenic progenitors (FAPs) contribute to irradiation-induced muscle atrophy and fibrosis, in part, through alterations to their secretome that impairs muscle stem (satellite) cell (MuSC) fate. It is unknown; however, which specific FAP secreted factors are responsible for the irradiation-induced defect in MuSC differentiation and fusion. Preliminary data from our lab and others suggests that Follistatin-like 1 (FSTL1) may be a key, irradiation-sensitive secreted factor. We aimed to understand how irradiation impacts FSTL1 expression in FAPs and elucidate how FSTL1 expression impacts the MuSC niche.
Methods: Fstl1 in vitro gene and protein expression was analyzed on irradiated C3H10T1/2 (C3H) fibroblasts (a FAP cell line) and primary FAPs. In vitro FAP differentiation was analyzed on FSTL1 knockdown C3H cells. Fstl1 in vivo gene expression was analyzed on mice that had one hindlimb irradiated. The effect of FSTL1 repletion was analyzed in vivo on mice that had both hindlimbs irradiated and rFSTL1 injected intravenously.
Results: In C3H cells, Fstl1 was significantly lower at 24-hours (p<0.05) and FSTL1 was significantly higher at 48-hours post-irradiation (p<0.01). In primary FAPs, FSTL1 was significantly lower at 12- and 48-hours post-irradiation (p<0.01). FSTL1 knockdown significantly lowered the area (p<0.01) and mean fluorescence intensity per cell (p<0.0001) of fibrogenically differentiated C3H cells. FSTL1 knockdown (p=0.0701) and irradiation (p<0.01) lowered the percentage of total C3H cells that were adipogenically differentiated. In vivo fractionated irradiation did not induce alterations in muscle-resident mononuclear cell populations, muscle fibrosis, and muscle cross-sectional area (CSA) at 3-days. Intravenous repletion of rFSTL1 raised FSTL1 in circulation (p<0.0910) but not in skeletal muscle.
Significance: The present study demonstrates that Fstl1 expression is decreased by in vitro irradiation, that it upregulates FAP fibrogenic differentiation, and downregulates FAP adipogenic differentiation. We identified FSTL1 as a compelling candidate for mitigating cancer treatment-induced skeletal muscle atrophy and fibrosis. Future work using a novel intramuscular FSTL1 repletion protocol has the potential to unveil benefits in in vivo myogenesis following irradiation
Automated Detection of Substance Use Through Social Mining and its Prediction Ability in the Canadian Population
No full textAccording to the latest WHO report in 2024, there is a significant increase in substance use disorders and environmental harms around the world. The report highlights that alcohol consumption was responsible for 2.6 million deaths annually, representing 4.7% of all world deaths, while psychoactive drug use accounted for 0.6 million deaths. The number of drug users increased to 292 million in 2022, reflecting a 20% rise over 10 years. Automated detection of different substance uses through social media can be an effective and practical observational tool for the global substance use problem. Automated detection of online communication has multiple applications, including helping people at-risk and protecting them by predicting and monitoring the early signs of risks on time. Our system can be used by individuals with authority (such as parents or doctors) to detect and monitor different substance users. It could raise an alarm to the relevant individuals to take necessary interventions for the early signs of substance use associated with the flagged posts. This thesis describes the process for classifying online posts to detect substance use problems as early as possible. We began by utilizing two datasets of annotated social media posts to train several classification models that predict whether these posts indicate signs of substance use. We assessed the performance of several traditional and recent deep learning models. Different CNN-based, RNN-based, BERT-based, and GPT models were found to be promising approaches in detecting substance users from their posts. GPT-4o, using a few-shot learning model, outperformed other models with 89.44% F1-score. Also, we built different user-level detection models for common substances (cannabis and alcohol). For cannabis user detection, GPT-4o using a few-shot learning model was the best-performing model with 85.22% F1-score, while the DeBERTa-v3 model was the best-performing model with 65.50% F1-score for alcohol user detection.
As a second objective, these models were used for the automated detection of different substance use at the population level in Canada. A common practice for substance use detection at the population level involves conducting surveys via phone calls or interviews; however, this approach is both time-consuming and expensive. Understanding Canadian trends in alcohol and drug use is crucial for developing and evaluating effective policies and programs at both the national and provincial levels. Examining social media posts can serve as a flexible alternative for identifying several substance use problems across Canada. We detected the population-level use of cannabis and alcohol from 2015 to 2018, based on representative samples. Then, we compared these results of the same years' official statistics from Health Canada for the two substances. We used the estimated reports from Health Canada until 2019.
Given the lack of annotated data for several substances, such as alcohol, we proposed a data augmentation technique that increased the information within the training phase by building several artificial training sets. Then, we applied the best generalized model (as mentioned before) for population-level detection. The results for population-level detection for both cannabis and alcohol were promising for the tested years and comparable with the results of the Health Canada surveys. The cannabis user detection achieved a difference of 5% or less from the governmental estimations for the nine Canadian provinces included in this study. Similarly, the alcohol user detection achieved a difference of 6.5% or less for the same group of provinces under study. To the best of our knowledge, this is the first study to propose the detection of substance use through social media for an entire country
Prison Pandemic Papers 2.0 – Nova Scotia
No full textThis dataset was collected through Access to Information requests submitted to the Government of Nova Scotia as part of the "COVID-19: Investigating Canada's Carceral Response to the Coronavirus through the Prison Pandemic Partnership" led by Kevin Walby (Full Professor, Criminal Justice, University of Winnipeg), Justin Piché (Full Professor, Criminology, University of Ottawa), and Abby Deshman (Executive Director, Canadian Civil Liberties Association). Initial triage of this dataset was undertaken by Mackenzie Plumb (PhD Student, Criminology, University of Ottawa).This research was funded by a Social Sciences and Humanities Research Council of Canada Partnership Engage Grant (1008-2020-0238)