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Advancing Generative Modelling and Applications with Boltzmann Machines, Restricted Boltzmann Machines, and Sum-Product Networks
Full text linkIn the era of advanced machine learning methodologies, generative probabilistic modelling shows great promise for solving real-world problems. This study focuses on Boltzmann Machines (BMs), Restricted Boltzmann Machines (RBMs), and Sum-Product Networks (SPNs), highlighting their abilities to reconstruct complex data distributions and produce meaningful outputs. Notably, BMs and RBMs excel at modelling data distributions, while SPNs utilize hierarchical structures for efficient representation and scalable probabilistic inference. Using the Fashion MNIST dataset as a benchmark, this work demonstrates the models' practicality through reconstructed images, precise predictions, and performance metrics. The findings confirm their applicability in tasks such as image generation, object recognition, and pattern matching. This study provides an empirical assessment of the strengths and limitations of each approach while expanding the potential applications of generative models in machine learning
NEW ROUTES IN BIOCATALYSIS: EXPLORING THE IMPACT OF GRAFTING SILICONES ONTO PROTEINS/ENZYMES
Full text linkOne of the cornerstones of our research is the use of biocatalysis to mitigate the negative impact of chemical processes on the environment. The majority of natural enzymes are highly efficient and can increase the rate of chemical transformations. However, the industrial application of enzymes is often restricted by several limiting factors such as poor operational or long-term stability, especially during exposure to elevated temperatures, organic solvents, and pH extremes. The chemical modification of enzymes using covalent conjugation is a very common stabilization strategy as it imparts stability and protects the enzyme from denaturation. A number of studies have determined that hydrophobic surfaces can have a very positive impact on the reactivity of various enzymes, particularly lipases. The impact of silicones on proteins, mostly through physical/noncovalent interactions has attracted considerable attention recently. Given our research team’s ongoing work in the area of silicone-proteins/enzymes interactions it was of interest to explore the impact of covalently conjugated silicone polymers on proteins.
Herein, a library of hydride-functionalized silicones of differing molecular masses was prepared using the living anionic ring opening polymerization of hexamethylcyclotrisiloxane (D3) to yield poly(dimethylsiloxane) (PDMS) polymers with narrow dispersities (Ð). These polymers were subsequently activated with hydrophilic functional groups including disuccinimidyl carbonate (DSCa) and norbornene dicarboxylate anhydride (NDA) prior to conjugation with proteins/enzymes. Human serum albumin (HSA) was selected as a model protein to study the PDMS/protein chemical interactions prior to the functionalization of enzymes. HSA’s well-documented spectroscopic behaviour as either a native protein or denatured species made it an ideal model to investigate the impact of covalently bonded silicones on proteins. After completion of model protein studies, trypsin and Candida antarctica lipase B (CALB) were modified chemically with functionalized PDMS polymers. The covalent bonding of PDMS polymer chains onto protein/enzyme was studied through matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry. The solubility of the protein/enzyme conjugates were examined in various organic solvents including tetrahydrofuran (THF), chloroform, dichloromethane (DCM), dimethylformamide (DMF), and toluene and confirmed by UV-Vis spectroscopy. The impact of silicones on the protein/enzyme structure was investigated by infrared (IR), circular dichroism (CD), and fluorescence spectroscopy. Thermal behaviour of the protein/enzymes before and after modification with PDMS polymers were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Catalytic function, thermal stability, and the accessibility of active sites of the enzymes of interest after conjugation to the functionalized siloxanes were studied through standard activity assays. This work demonstrates that not only can siloxanes be successfully coupled to proteins, but the bioconjugation also enhances the solubility and activity of enzymes in organic solvents
Thermoregulation differences during heat stress between children and adolescents/adults – a systematic review
Full text linkIt has been well-recognized that children and adults utilize homeostatic mechanisms to regulate their core temperature differently in the heat. Adults predominantly rely on sweat evaporation to dissipate excess heat, while dry heat dissipation (radiation, convection, and conduction) is more dominant in children, through increased skin blood flow. Despite numerous studies, there is limited collective evidence on the different uses of homeostatic mechanisms and outcomes in the heat between children and adults. We aimed to compare the use of temperature regulation mechanisms and outcome during heat stress between children and adults. Outcomes measured included final core temperature or change in core temperature following exercise in thermoneutral or hot conditions. Electronic databases were searched for studies assessing core temperature, sweating rate, and skin blood flow in children and adults, in English, with no publication year limit. Of the 4683 studies initially screened, 21 met the eligibility criteria. Those are included in this analysis for a total number of 415 research participants. Of the 18 studies that reported core temperature during heat stress exposure, 5 studies reported significantly higher core temperature in children, due to their higher baseline core temperature. However, the change in core temperature was not different between groups in any of the studies. In 18 of the 21 studies that examined sweating rate, 15 studies reported significantly lower (13-74%) sweating rate per surface area (or per gland) in children compared to adults, while 3 studies reported no significant difference between groups. Of the 10 studies that examined skin blood flow, 7 studies reported higher skin blood flow in children compared to adults in the chest and/or forearm (16-83%), 2 studies reported lower skin blood flow in children (in the forearm and finger), and 3 studies reported no group differences in skin blood flow (in the forearm). In summary, the available data show similar thermoregulation outcome in children and adults, despite the different use of means of heat dissipation. Inconsistencies among studies reporting differences in heat dissipation between children and adults may be related to differing states of training or of acclimatization. More research is needed to examine thermoregulation in the heat in girls compared with women
TEMPLE: Resistance Embodied as a Diaspora Aesthetic Strategy
Full text linkTEMPLE: Resistance Embodied as a Diaspora Aesthetic Strategy is the working title for my PhD thesis and research/artistic creation project. It highlights my interest in the embodied manifestations of resistance as generated through disciplinary aesthetic practices. The project navigates through the entangled terrain of Diaspora experience in an attempt to excavate uncharted material that Black Studies scholar Katherine Mckittrick has termed, ungeographic and visual art critic Kobena Mercer describes as undiscovered. The qualitative research component for this project explores the everyday strategies of resistance used by contemporary Black women at the intersection of martial art practice, Diaspora visual art, social justice and community activism. The artistic creation components include the construction of an immersive, digital deep map using AR (augmented realities) technology and archival, personal and qualitative data. Through both research and artistic creation, I investigate the embodied and aesthetic experiences of selected contemporary Black women martial arts practitioners and historical women figures occupied in active resistance. My aim is to construct a theoretical and artistic space in which to witness, engage and reflect on the value of Black women’s resistance and social contribution through martial art. Overall this study highlights the conflicted tensions of a political and social struggle that persists against the “Black body” as a “violated” other – and Black women martial artist’s efforts to resist those discourses through embodied practice.
This research creation project is divided into several components: a series of essays that interrogate the creative and qualitative praxis of the research; a deep map that indexes the historical overview of martial art, martial arts women and resistance movements; an artistic installation using AR technologies that allows the viewer to interact with the researched material and a dedicated interactive website that provides digital access to some areas of the research.
Keywords: Martial art; Black women martial artists; embodied space; body practice; performative pedagogy; digital embodiment; resistance; resistance history; social justice; community activism; Diaspora; Black diasporic gaze; Diaspora aesthetics; Diaspora archive; Diaspora conscious unconsciousness; art-led research; augmented realities technologies; digital visualizations; digital deep ma
Service Providers' Perspectives on Abortion Access Challenges for People with Precarious Housing and Migration Status in Niagara, Ontario: An Interpretive Description Study
No full textAbortion is a common and essential part of healthcare. However, barriers to accessing
abortion care are not experienced equally, and for those with precarious housing and/or migration
status (PPHM), accessing abortion care can be even more difficult. To better understand this
issue, the study explored the barriers service providers face in providing and facilitating abortion
care to PPHM in the Niagara region of Ontario, Canada. Grounded in reproductive justice and
structural violence theoretical frameworks, and employing an interpretive description
methodology, this qualitative study aimed to understand how we can better support service
providers so that they may better support their clients. The study was conducted in collaboration
with a local community partner, Niagara Reproductive Justice. Utilizing semi-structured
interviews with fifteen service providers from a range of fields, the research aimed to document
the process of facilitating abortion care, the related barriers and facilitators, and explore how to
build meaningful community capacity. Three themes were identified from the data analysis: (1)
Organizational silos, (2) The compounding impacts of abortion stigma, and (3) The power of
peer support and communities of practice. This study also contributed to the existing knowledge
in two major ways: (1) by making visible the role of the social sector in abortion care provision
for PPHM clients and (2) by deepening our understanding of the impacts of abortion stigma.
Recommendations from service providers are presented, along with a discussion of practical
implications and directions for future research
Investigating the effects of aging and the neuromodulator retinoic acid on neurite outgrowth in a novel CNS organ culture
Full text linkNeurite outgrowth is a critical process for nervous system regeneration following
injury. However, aging impairs this process through changes in calcium handling,
neurotransmitter sensitivity, and energy metabolism. In this thesis, I investigated agerelated changes in neurite outgrowth using a novel central nervous system (CNS) organ culture, in which outgrowth can be observed from cut nerves resting on the surface of culture media. I demonstrated how aging significantly reduces the ability of the CNS to
initiate outgrowth and that individual nerves differ in their regenerative capacity, exhibiting
either vulnerability or resilience to age-related decline. Further, I explored the effects of
retinoic acid, a vitamin A metabolite that influences neurite outgrowth. Retinoic acid
promoted outgrowth in the CNS from young animals but not aged animals, and high
concentrations of retinoic acid impaired outgrowth at all ages. These findings provide new
insights into age-related deficits in neurite outgrowth and their modulation by retinoic acid
signaling
Towards Multifunctional Materials based on Coordination Complexes of Sulfur-Containing Diarylazo and Cucurbit[6]uril Ligands
Full text linkIn this thesis, the coordination chemistry of two families of ligands are explored, working
towards the discovery of new multifunctional materials.
The first project focuses on the coordination chemistry of sparsely reported redox active
sulfur-bearing diarylazo ligands. Homoleptic complexes with ligands 2-5 were successfully
prepared with Cu2+, Ni2+ and Co2+/3+, in addition to Co3+ heteroleptic complexes containing 7.
Single crystals suitable for SCXRD were isolated for complexes 4e, 5a, 5a’ and 5c. The complexes
were fully characterized and select complexes were further investigated by cyclic voltammetry,
EPR spectroscopy and magnetic susceptibility studies. EPR measurements of 4c at 80 K and RT
revealed noticeable differences in profiles suggesting the occurrence of structural and/or electronic
changes with temperature. DC magnetic studies on 4c and 5a reveal the expected LT χMT values,
however RT χMT values increase to 0.75 cm3Kmol-1 and 0.54 cm3Kmol-1, respectively.
The second project explores the hydrothermal synthesis of Ln4-cubane sandwich-type
structures from cucurbit[6]uril and isonicotinate together with suitable Ln3+ salts. A family of
complexes with two structural topologies were isolated; [Gd4(µ3-OH)4(µ2-OH)4] (8a) and [Ln4(μ3-
OH)4(μ2-OH)(µ2-IN)] (where Ln3+= Dy or Tb; 8b, 8c). The complexes were structurally and
magnetically characterized. Structural analysis reveals 8a has a different structure when compared
to the isostructural 8b and 8c. The 8-coordinate square antiprismatic coordination geometry for
the oblate Ln3+ ions in 8b and 8c serves to increase the axial anisotropy. DC magnetic studies
reveal the magnetic cores of the molecules are magnetically isolated with weak antiferromagnetic
interactions in 8a. AC magnetic studies reveal slow relaxation of magnetization consistent with
SMM properties in 8b and 8c. Modelling the magnetic data afforded effective energy barriers of
17.6 K (in zero DC-field) for 8b, and 11.1 K (5000 Oe) for 8c. Photoluminescence studies on 8a
reveal transitions associated with the CB[6] ligand. Partial and full energy conversion from the
ligand to the metal ion upon excitation, for 8b and 8c, respectively. Although DC magnetic studies
on the Gd3+ have been previously reported, the Dy and Tb complexes are the first reported Ln4-
CB[6] complexes to display slow relaxation of the magnetization consistent with SMM properties
Can Direct Service Providers Change Their Ability to Attend in The Present Moment with Mindfulness Training in Virtual Reality?
Full text linkOccupational burnout can severely impact various aspects of life, with Applied Behaviour
Analysis (ABA) direct service professionals (DSPs) experiencing high turnover rates, as shown
by the Behavioral Health Center of Excellence® (BHCOE®). However, research on burnout
specifically among ABA DSPs is limited, as is the use of mindfulness-based interventions aimed
at alleviating it. This study sought to introduce mindfulness-based interventions through virtual
reality (VR) and measure burnout levels, attentiveness and present-moment awareness.
Participants used the Maslach Burnout Inventory (MBI) and the Sustained Attention to Response
Test (SART) as pre- and post-test measures, defining burnout through inattentive behavior. After
learning to use VR headsets, participants completed baseline sessions, each followed by a VR
Attentiveness Test (AT) with 20 questions assessing their attention. If participants scored 70% or
below across three consecutive sessions, they began a mindfulness-based intervention, following
a VR-adapted curriculum by Holland et al. (2021) under researcher guidance. This intervention
continued until participants reached 80% or higher on attentiveness tests across three consecutive
sessions. Upon achieving this criterion, they completed the post-test and an exit survey. To
ensure interobserver agreement and procedural fidelity, at least 33% of all baseline and
intervention sessions were observed in VR by the researchers. Findings showed a reduction in
emotional exhaustion and depersonalization, alongside improvements in attentiveness,
suggesting that VR mindfulness interventions may help mitigate burnout in ABA DSPs. This
study highlights the potential of VR mindfulness interventions to reduce burnout in ABA DSPs,
offering an innovative approach to support mental health in high-turnover professions.
Key words: Burnout, direct service professionals, virtual reality, mindfulness, attention, job
satisfaction
St. Catharines photographs, 1901, 1912, n.d.
Full text linkEdwin Poole (1845-1931) was a photographer who worked in St. Catharines for much of his career. He is well-known for his portrait work, but he photographed much of the landscape and many buildings in St. Catharines as well.
The Russell House Hotel was located at the corner of James St. and St. Paul St. It was built in 1843 for Samuel Stinson. The building had many owners over the years including James Cairn and John Quinn. It remained a popular hotel into the 1920s and 1930s, but gradually declined throughout the rest of the century. It was demolished in 1996.
A.J. Gilmore Garage was located on St. Paul Street in St. Catharines. In the 1920s Garden City Motors took over, followed by Malcolm Motor Sales and W.E. McDermott’s garage (1934-1936). It was subsequently used by the Canada Bread Company, Garden City Motors again, Leon’s Furniture in the 1960s and 1970s, and by 2009 Wally Wemnants carpetmarket.Four black and white photographs from the St. Catharines area. Two of the photographs are portraits taken by [Edwin] Poole in St. Catharines and measure 10.5 cm x 16 cm. One portrait shows a woman with two boys. The other portrait is a head and shoulders photo of a man in a suit.
The other two photos are larger. The smaller of the two photos measures 21 cm x 15 cm and shows a line of cars in a building on one side, and a line of men and women along the other side. Writing on the reverse of the photo reads “A.J. Gilmore Garage, 1912 all Cadilacks”. It is mounted on cardboard.
The last photo shows two men sitting in a car on a bridge and measures 22.5 cm x 15 cm. Handwriting on the bottom left of the photo reads “Jno. Quinn, proprietor, Russel House, St. Catharines”. In the bottom centre the word “Oldsmobile” is written. It is dated 1901 at the bottom right of the photo and is mounted on paper
Consumer Desires in the Niagara Wine Industry: A Geodemographic Analysis of Customers at a Niagara Winery
Full text linkThe wine tourism industry is a global industry. Here, the focus will be primarily on winery visitors in the Niagara Region. More specifically, I explore what motivates them to visit wineries and what they hope to experience during their visits. Given significant competition, wineries must cater their expectations to attract visitors to their cellar doors. The purpose of this thesis is to determine whether geodemographic factors (type of community, municipality, general location) in combination with the demographic (age, gender, education, income) factors have an impact on what motivates people to visit wineries and what they expect once they arrive. More precisely, this thesis aims to answer the research question: “Do visitor origin and associated demographics make a difference in motivation to visit a winery and visitor experience expectations?” While doing so, I examine the two sub-themes. First, and as noted above, I seek to explore whether there is there a correlation between expectations for winery experiences and residence of trip origin and other demographic characteristics. Second, I ask “What winery features are visitors hoping to experience?” Using the mailing lists of one small, recently rebranded boutique winery in Jordan Station, Ontario I distributed web-based surveys to collect data on October 3 and 20, 2023. The survey was distributed through two mailing lists (the general mailing list and wine club list to 1568 individuals. A total of 133 individuals responded. Following the data collection process, I used qualitative and quantitative data analysis including coding, cross tabulations, Chi-Square tests, and location analysis though ESRI Community Analyst to explore the data. The analysis did not provide conclusive answers that suggests that location and geodemographic characteristics were significant in determining motivations to visit the winery. The results did, however, allow me to reach the conclusion that visitors are attracted to the experience and social aspects of wineries over
the wine itself. In sum, the data collected can provide valuable information, both practical and academic contributions, on how to cater experiences to a larger audience