Morphological, Histological, And Developmental Features Of Perichondral Bone In Skates And Sharks Suggest That Modern Cartilaginous Fishes Make Bone

Bone is a mineralized (or calcified) tissue type and a defining feature of the vertebrate skeleton. Ancestral vertebrates made bone and most modern vertebrates including bony fishes and tetrapods retain bone. However, bone has never been characterized in modern chondrichthyans (sharks, skates, rays, and chimaeras), and modern chondrichthyans are hypothesized to have lost the ability to make bone during their evolution. Previous studies show that sharks have mineralized tissues with some morphological and histological features that are consistent with vertebrate perichondral bone. These mineralized tissues in sharks have been described as bone-like and occur in neural arches and a specific histological region (i.e., cap zone) of discretely mineralized tesserae. While these observations in sharks challenge the hypothesis that modern chondrichthyans lack bone, it remains debated whether other modern chondrichthyans like skates and chimaeras have bone-like tissues. Because bone-like tissues have been characterized mostly in adult sharks, it is not known whether important developmental features of perichondral bone such as cartilage maturation is demonstrated by bone-like tissues. Besides bone-like tissues, chondrichthyans also display a unique areolar mineralized tissue in the vertebral body (centrum). These chondrichthyan mineralized tissues display distinct mineralization patterns such as a classic polygonal pattern of tesserae, a compact bone-like pattern of neural arches, and a compact pattern of areolar mineralized tissue. These chondrichthyan mineralization patterns have been described in sharks and skates, but relevant data from chimaeras needed to assess whether all groups of modern chondrichthyans demonstrate these morphological features are lacking. This thesis addresses these and other knowledge gaps in the skeletal biology of modern chondrichthyans by testing the hypothesis that bone-like tissues are shared by modern chondrichthyans and are homologous to perichondral bone in other modern vertebrates. Comparative morphology and embryology were the two main approaches adopted to test this hypothesis. Specifically, mineralized tissues in two skate species (the little skate Leucoraja erinacea and the Eaton’s skate Bathyraja eatonii), a shark (the catshark Scyliorhinus canicular), and a chimaera (the spotted ratfish Hydrolagus colliei) were characterized using desktop and synchrotron micro-CT imaging, histological, histochemical, and immunofluorescence assays. Micro-CT renderings showed a bone-like mineralization pattern in neural arches of the skates and the shark, but this was absent in neural arches of the spotted ratfish. Micro-CT renderings and histological analyses of tesserae showed that the bone-like cap zone was present only in the skates, and the polygonal tesseral mineralization pattern was associated with large and laterally extensive bone-like cap zones. Another mineralization pattern described herein as trabecular tesseral was characterized in several endoskeletal regions of the skates, the catshark, and the spotted ratfish. The trabecular tesseral pattern was morphologically distinct from the polygonal tesseral pattern which is classically associated with the chondrichthyan endoskeleton. Micro-CT renderings and histological data also showed that areolar mineralized tissue, which has been described in only sharks and skates, was also present in the spotted ratfish. Perichondral bone formation in other modern vertebrates is driven by cartilage maturation. Developmental data from the little skate showed that the main histological features of cartilage maturation, such as chondrocyte hypertrophy and initiation of matrix mineralization by hypertrophic chondrocytes, were associated with the development of bone-like tissue in neural arches. In addition to limited reports of bone-like tissues in sharks, data in this thesis showed that other modern chondrichthyans like skates have bone-like tissues. Developmental features of perichondral bone demonstrated by neural arch bone-like tissue suggest that bone-like tissues and perichondral bone are homologous

The Rainbow Bike Experiences of School for Parents Whose Children Have Needs: A Narrative Inquiry into Whose Knowledge Counts

Having chosen narrative inquiry as my research methodology, I sat for hours in my first narrative inquiry class wondering how I was going to tell my story. I observed countless examples of rich narratives. They all spoke to me in different ways, but I still did not know how to begin. Finally, the metaphor of the rainbow bike crashed into my head, just as it crashed so long ago as a little girl. I decided to use the rainbow bike metaphor to conceptualize and tell my story of experience and as an entry into this narrative inquiry. As a child, my rainbow bike was a place of escape from pain and hurt. As a narrative inquirer in the field, I continued to ride my rainbow bike when I needed help to carry the heaviness of the stories my research participants shared and I needed to escape to places of safety and comfort to unpack those stories. As I engaged in analysis and interpretation of my field text, my rainbow bike carried me to places of discovery and joy. Now, as I conclude this narrative inquiry, I park my rainbow bike for some much needed rest. It was through writing my own narrative beginnings that I learned how to portray the lived experiences and stories of my research participants: three pairs of parent partners who have a child with needs, the term I use to step away from the language and labelling of ‘special needs’ that ‘others’ children and their families. Parents with children with needs often find themselves pushed to the margins at their children’s schools, seen to be lesser than other parents, seen to be less knowing. My purpose in inquiring into their lived experiences was to foreground the parent knowledge they hold, individually as parents and together as parent partners, that can be used alongside teachers’ knowledge to inform their children’s schooling experiences. Attentive to the three-dimensional space of this narrative inquiry, I captured participants’ stories as they unfolded over time, moving between earlier moments, present realities, and imagined future possibilities. I was drawn to their innermost thoughts and feelings as we engaged in conversations in the social space of our living rooms. Through the sharing of our stories, we journeyed to childhood homes, communities, and schools. This narrative inquiry has been a long and in-depth rainbow bike ride, backward and forward, inward and outward, visiting many places during the sharing of stories of our lives. As stories were lived and told, I understood more deeply how parent knowledge is held and used, either individually, exercised as a form of roving leadership within their partnership, or co- constructed to create new shared knowledge for both parents. It became clear that if parent knowledge is used alongside teacher knowledge, it is possible to dramatically transform the current hierarchy of schools, creating teaching and learning centres in which parents have a place and voice. It is my hope that the lived experiences of the parents in my inquiry have been educative for themselves and will be for other parents on a similar journey, for educators who will “walk alongside” the parents as their children with needs enter schools and school systems, and for schools and school systems in which some parents and families find themselves in the margins of the school landscape

Tribological and Corrosion Behavior of Cold Sprayed Fe-Based Bulk Metallic Glass Coating on Aluminum Alloy

The abstract of this item is unavailable due to an embargo

The Efficacy of Individualized Last Repetition Velocities for Autoregulating and Monitoring in Resistance Training

Traditional resistance training (RT) methods often involve a fixed prescription based on a pre- determined percentage of one-repetition maximum (1RM); however, a plethora of variables may impact an individual’s performance on a micro- and macro-level: fitness, fatigue, readiness, amongst several others. Autoregulated resistance training has developed as a potential framework to rectify traditional methods by systematically measuring and adjusting the programming prescription on a short-, medium-, and long-term monitoring basis according to an individual’s performance and context-specific goals. Although initial findings have provided some evidence to support the efficacy of autoregulation on muscular adaptations in college-aged resistance- trained males, the available evidence is unclear whether autoregulation indeed provides a greater advantage over traditional methods for additional neuromuscular adaptations, performance outcomes, and functional measures in varying populations and females. Therefore, the primary purpose of this PhD thesis/dissertation was four-fold. The initial purpose was to systematically review and meta-analyze the existing evidence on the effect of load and volume autoregulation on muscular strength and hypertrophy adaptations. Autoregulated compared to traditional load prescription resulted in significantly greater increases in 1RM strength. Autoregulating volume with lower and higher magnitudes of intra-set fatigue were most effective for improving 1RM strength and hypertrophy; respectively. The second purpose was to conceptualize a theoretical velocity-based training model based on the advantages and limitations of the current traditional and autoregulation methods: the Individualized Last Repetition Velocity Model (LRV Model), which is described in a narrative review. The third purpose was to compare the accuracy of subjective estimations to objective velocities (an iteration of the LRV Model) at quantifying proximity to failure for the bench press in resistance trained males and females across numerous parameters, in which objective velocities displayed significantly greater accuracy. The final purpose was to compare the efficacy of traditional methods, subjective autoregulation, and objective autoregulation (the LRV Model iteration) for load prescription on neuromuscular adaptations, performance outcomes, and functional measures in older adult males and females. Objective autoregulation elicited the best improvements in bench press strength and knee extensor hypertrophy. This thesis provides novelty regarding the efficacy of individualized average concentric last repetition velocities for autoregulating and monitoring

The Regulation of Social Media in Nigeria and its Effect on Free Speech: Perspectives from Constitutional Law and International Norms

This thesis explores the multifaceted and evolving topic of social media regulation, with a focus on Nigeria. As social media platforms have become central to communication, information dissemination, and public discourse, concerns have arisen about their impact on individuals, society, and democracy. The research question addressed in this thesis is whether the Nigerian bills on restriction of social media can legally restrict false speech and hate speech without overreaching on the right to freedom of expression, and if not, what measures can be taken to improve these bills. The thesis begins by analyzing three key theories for the justification of freedom of expression, which show that freedom of expression is essential to the discovery of truth, self-autonomy, and promotion of an open and vibrant democratic discourse. However, these theories are not an absolute justification and may be restricted. The thesis also examines the conditions for justification of limits on freedom of expression in Nigeria, which is that the law must be shown to be within reasonable limits permissible in a democratic society. Section 45 of the Nigerian Constitution states specific grounds for the restriction of freedom of expression, but the section is vague as it gives no further direction as to how Nigerian courts should balance competing interests, such as freedom of expression on the one hand and public interest on the other. The thesis argues that the importation of proportionality analysis and international standards is necessary to restrict hate speech and false speech in Nigeria while protecting the right to freedom of expression. The delicate balance between preserving freedom of expression and addressing harmful content, such as hate speech and false information, is a critical consideration in social media regulation. The thesis suggests that drawing from Canadian law and international standards could enhance Nigeria’s regulation of free speech on social media. The thesis concludes that the protection of freedom of expression is crucial, especially in a diverse cultural, political, and socio-economic landscape such as Nigeria

A Theoretical Examination of Contributing Factors to the Proliferation of Political Vigilantism: Evidence from Ghana.

Political vigilantism has been a significant issue in many parts of the world, and it has undermined the rule of law and democratic processes in Ghana. Political vigilantism is understood as actions taken by individuals and/or quasi-institutions other than state officials which could either be extralegal or illegal mostly typified by violence in the political field. Ghana, in particular, has been affected by political vigilantism, and it is considered a major obstacle to political development in the Fourth Republic. This study uses an institutional performance-focused theoretical framework comprising the theories of structuration, legitimacy, institutional failure, and social learning to test the significance of the identified factors contributing to the prevalence of political vigilantism. The study employs a mainly qualitative methodology to answer the research question: “Does the theoretical framework explain the contributing factors of political vigilantism in Ghana?” The findings indicate that key state institutions have failed to fulfill their constitutional mandates and that political interference has motivated the spread of vigilante activities in Ghana. The results further suggest that a combination of factors, including unemployment, poverty, high illiteracy rates, and politicians’ desire for power, has sustained political vigilantism. Finally, the study recommends that allowing institutions such as the electoral commission and criminal justice agencies to work independently and without political influence will reduce the prevalence of political vigilantism, which has marred the beauty of Ghanaian democracy. This study contributes to our understanding of political vigilantism and its implications for theory, policy, laws, and further research. In conclusion, without institutional independence and strict adherence to the rule of law, political vigilantism will continue to be a major issue in Ghana’s political development

Targeting regulatory T cells in experimental colon cancer with radioimmunotherapy

Colorectal cancer remains a formidable threat to human health around the world and has become the third most common cancer worldwide. However, over the past 20 years, there has been a lack of breakthroughs in the treatment of colorectal cancer, especially for advanced colorectal cancer. Only a limited number of treatment options are available, and treatment outcomes significantly vary. Immunotherapy with immune checkpoint inhibitors while becoming a game changer for various types of cancer, produces mixed results in colorectal cancer with only a small number of patients experiencing long term progression-free survival. Regulatory T cells (Tregs) are an immunosuppressive subset of T lymphocytes, and a particular subset of Tregs, so called tumor infiltrating Tregs (ti-Tregs) can interfere with immunotherapy mechanism of action resulting in decreased efficacy. In recent studies, CCR8, or C-C motif chemokine receptor 8, has emerged as a highly expressed cell surface protein found exclusively in tumor-infiltrating Tregs, including those in colorectal cancer tumors. This makes CCR8 a promising target for radioimmunotherapy (RIT) to selectively eliminate ti-Treg cells. RIT allows for precise delivery of highly cytotoxic radionuclides to localized or systemic cancer deposits. In this study, we tested the hypothesis that using CCR8 as a target in RIT could eliminate ti-Tregs within colorectal tumors, potentially enhancing the success of subsequent immunotherapy. We validated the ability of our antibodies to bind to ti-Tregs in colorectal cancer tumors in mouse tumor models by microSPECT/CT imaging and confirmed a reduction in ti-Treg cells post-RIT with 225Actinium-labeled anti-CCR8 antibody within the experimental group's tumor samples through immunohistochemistry (IHC) analysis. Subsequent combination therapy experiments with 225Actinium-labeled anti-CCR8 antibody and anti-CTLA4 immunotherapy established the feasibility of the combination therapy in mouse colorectal cancer models, revealing a synergistic effect of the RIT and immunotherapy combination. The results of these combination therapy experiments suggest a more effective strategy for colorectal cancer treatment which can also be a viable approach for various other cancer types. In other words, choosing CCR8 as a treatment target for RIT to enhance the success of subsequent immunotherapy holds significant promise, regardless of the specific cancer type, if high CCR8 expression ti-Tregs exists within the tumor microenvironment

Analysis of Electronic and Magnetic Properties at the Interfaces of Transition Metal Heterostructures

Material science is a field of physics that bridges the gap between the microscopic properties of materials and how these properties manifest as tangible, observable characteristics that can be observed or harnessed for applications. Material scientists grow, analyze, modify, and model complex, exotic materials to understand emergent, novel phenomena and create devices which can readily be employed for electronic, magnetic, and other applications. However, many material properties cannot be measured or observed directly; it is not feasible to measure the orbital energies of an atom directly or quantify angstrom-scale magnetic variations in a thin film sample directly. Since these properties are frequently what create meaningful effects at a macroscopic level, an understanding of them is required that only material science techniques can provide. This thesis concerns two separate studies of complicated material systems that require an understanding of their underlying structure and properties that cannot be directly discerned by experiment alone. These samples belong to a class of materials known as heterostructures, structures formed by layering multiple materials with different chemical/elemental compositions. The junctions where different materials in a heterostructure connect are called interfaces, and serve as the sites of emergent physical and chemical phenomena with a myriad of electronic and magnetic applications. The first material system studied is the interface of bulk LaAlO3 and bulk CaTiO3, often simply abbreviated as LAO/CTO. Systems containing interfaces between transition metal compounds have been intensely studied within the past two decades because certain phenomena such as two-dimensional electron gases (2DEG), magnetism, and other effects tend to appear specifically around the interface. Historically, a combination of bulk LaAlO3 and bulk SrTiO3 (LAO/STO) was studied instead, but the interfacial effects can be changed by swapping out various elements in the compound. This variation is due to the crystal structure near the interface being distorted according to the element introduced, altering the Ti orbital energies near the interface as well. These near-interface orbital energies directly correlate to observed interfacial phenomena, so swapping elements is expected to affect the macroscopic electronic and magnetic properties of the system. The difficulty resides in the fact that orbital energies and 2DEG charge densities cannot be measured directly by any experiment; rather, they need to be extracted from experimental data via sophisticated modelling. The purpose of this study was to probe two samples of LAO/CTO with varying thicknesses, use the extracted experimental data to generate models of the two samples, and finally use this model to discern orbital energies. Special consideration was given to comparing and contrasting the difference between the LAO/STO interfacial electronic structure with that obtained for LAO/CTO. It was found that the orbital energies of LAO/CTO maintain a significantly different configuration from those of LAO/STO, and suggest that LAO/CTO may be more promising for magnetic applications. Furthermore, this difference will foster more investigation into interfaces of this kind, particularly in designing new configurations of different metals to observe what macroscopic effects they produce. The second material system studied is thin films of Fe3GeTe2, often abbreviated FGT. FGT as a bulk material has been studied since the turn of the millennium for potential magnetic applications, and attention has recently moved towards growing the substance in thin film form on the order of angstroms thick. Several sources have found that the electronic and magnetic properties of these thin films vary dramatically vary dynamically as more FGT film layers are grown sequentially in one sample. However, this information is only known at a high level; the magnetic effects are known to differ, but how exactly this manifests on a microscopic level is unknown. Given the angstrom level thickness of the films, it is extremely difficult to probe the magnetic properties in detail. A more sophisticated technique is needed, so here we apply resonant X-ray reflectometry. This study considered two samples: a single FGT layer film (monolayer) and a combination of two FGT layers as a film (bilayer). Experimental results were used to synthesize a model of each film and the magnetized iron distribution was quantified in each case. The two samples were found to have differing magnetized iron distributions, further lending credence to observations that FGT films of various layers will produce different magnetic properties and effects. These two studies represent intriguing but very limited applications of material science. New exotic materials are being actively discovered all the time, each with their own unique need for a method that probes their microscopic properties to understand macroscopic phenomena. Material science techniques are and will continue to be important for these reasons; advancement of technology is now reliant on synthesizing and understanding new materials that improve electronic and magnetic infrastructures, an understanding that material science provides

EXAMINING THE SOCIAL EXPERIENCE IN A VIRTUAL CULINARY NUTRITION EDUCATION INTERVENTION: THE COGNITIVE KITCHEN

Background: Evidence suggests preventing or delaying the onset of dementia could have a substantial impact on both direct and indirect costs of health care as well as individual burden. It is estimated around 40% of dementia cases could be prevented through the reduction of modifiable risk factors. Following a nutritious eating pattern is one strategy to reduce the risk of cognitive decline and dementia, but knowledge on how to encourage adoption of dietary patterns shown to support brain health is limited. Being socially active and engaging in cognitively stimulating activities are also recommended dementia risk-reduction behaviours. Cooking classes provide a unique setting where social contact can be integrated with continued education and practical application of nutrition-related dementia risk-reduction strategies (i.e., through food preparation). Interest in studying virtual cooking class delivery has recently increased, with some circumstances making remote attendance appealing (e.g., to reduce travel during inclement weather and illness outbreaks, potentially reduce program costs associated with space rental). Very little published literature captures the feasibility of virtual cooking class delivery in maintaining key program outcomes identified in conventional in-person classes—namely, social interaction. For a dementia risk-reduction-focused virtual intervention in particular, understanding strategies to enhance social engagement is valuable to maximize outcomes for participants. Aim: Examine older adult participants’ experience of the social component of a virtual culinary nutrition education intervention for dementia risk reduction. Methods: The Interpretive Description (ID) methodological approach was used to explore participants’ experiences from two separate but identical offerings of a pilot virtual Cognitive Kitchen program. Data sources for this qualitative study included session observation fieldnotes, end-of-program focus group discussions with each group, participant digital journal entries (45 submissions), and semi-structured individual interviews (n=15, comprised of 13 individual interviews and one shared interview). The two focus groups and 14 interview recordings were transcribed verbatim and analyzed with the other data. Thematic analysis led to the identification of four themes that capture what was learned about the social component of the virtual Cognitive Kitchen from participants’ experiences. Findings: The themes respond to the research objectives of this study by describing the function of social interactions in the program and facilitators and barriers to social engagement in the virtual setting. Social interactions were described to contribute to key program outcomes related to providing culinary and nutrition education and promoting engagement in cooking, as represented by the themes Supporting Learning and Encouraging Application. The theme Trade-offs: Advantages and Missed Connections presents both benefits and drawbacks of the virtual setting that were identified to impact the social component of the program. Lastly, recommendations for future offerings of the Cognitive Kitchen are presented in the theme Ingredients for Engagement. Conclusion: The social component of the virtual Cognitive Kitchen was valued by participants and contributed to the achievement of key program outcomes. Specifically, contributions from group members were described to enhance the educational content on nutrition and socialization-related dementia risk-reduction strategies. Additionally, the group setting provided accountability for many participants to engage in home cooking and social interactions appeared to function to promote cooking as an activity to support well-being. The findings also capture that some social experiences are unable to be replicated via web-based programs. As such, additional effort by facilitators is necessary to enhance social engagement among participants in virtual culinary nutrition education interventions

The Transformative Power of Self-Compassion for Women Exercisers

Awareness of the challenges women face in feeling safe and comfortable in their bodies has grown significantly. Despite this increased awareness, body shame remains a prevalent experience. Research has shown that even brief moments of self-compassion can reduce body shame, decrease the reliance on physical appearance for self-worth, and promote appreciation for one's body as it is. However, understanding how self-compassion influences exercise behaviour and subsequent feelings about the body requires further exploration. My participatory action research study aimed to find ways to emancipate women’s relationship with exercise and their bodies and explore new ways of relating to themselves through movement. I worked with ten participants over three months, through workshops and group discussions. My findings revealed the profound impact of self-compassion in the context of exercise. The research process validated the relevance and pervasiveness of the challenges that exist by inhabiting a woman's body and highlighted the positive impact that results when everyone’s experience can be expressed and held in communion with other women. The findings supported the use of self-compassion concepts to challenge internalized narratives and cultural influences, fostering the courage to make authentic and meaningful changes in exercise beliefs and behaviours by adopting a kind and caring approach to oneself during exercise planning and engagement. Overall, the research revealed that while self-compassion created a space that enabled an alternate worldview, and one that inherently fostered the ability to turn toward oneself with care, the process was greatly enhanced through the group experience, shared vulnerability, resonance, mutuality, and common humanity, all fostering an ability to embrace one’s humanity