VictorJuiz/thesis huggingface dataset:
Durability testing protocols for concrete made with alternative binders and recycled materials

Recent strategies to reduce the carbon footprint and environmental impact of concrete include the reduction or elimination of portland cement and utilization of waste materials. The impact of these changes on the durability of concrete is an active area of research, but less-so in terms of the characterization and interpretation of the micro-structural responses of these new concrete mixtures to traditional durability tests. This research explores novel approaches for performing durability tests that are commonly used in the areas of chloride ingress, external sulfate attack, and alkali silica reaction (ASR) in an effort to refine and improve the current methods of testing. To validate a durability testing approach, its suitability and effectiveness should be checked against a wide range of concrete compositions, hence, various mixtures with different physical and chemical characteristics, including binders with either straight portland cement, alkali activated slag, alkali activated fly ash, or alkali activated metakaolin were prepared and tested. First, a micro x-ray fluorescence (µXRF) method was developed to measure chloride ingress through the use of multiple calibration curves to account for matrix effects across the variety of binder systems. Second, two different sulfate resistance testing protocols were compared, and a similar µXRF approach was developed to measure sulfate ingress, with phase changes evaluated by a scanning electron microscope combined with x-ray energy dispersive spectrometry (SEM/EDS). Third, a new digital-image-based approach for conducting the damage rating index (DRI) was developed and the indexes were compared with the traditional method. Finally, the addition of fibres recovered from recycled glass fibre reinforced polymer (GFRP) was found to be innocuous in terms of ASR expansion in accelerated mortar beam and concrete prism tests, and the pozzolanic reactivity of the recycled GFRP fibres was confirmed by SEM/EDS.

Keywords: alkali activated material
concrete
durability
geopolymer
Advisor: Peterson, Karl
Redefining Pluripotent Stem Cells: A Cell Cycle Perspective

As it is classically defined, the term stem cell seems at odds with the process of early development where, at least initially, there are no discernable cell fates. However, a paradox exists: not all pluripotent cells found the embryo, whether that cell is an epiblast cell or its in vitro counterpart, the ES cell. In this thesis, the supposition that all pluripotent cells are intrinsically equivalent from a functional perspective is challenged. We provide evidence that not all ES cells are by definition bona fide stem cells. In addition, we show that the two hallmark features of a stem cell are independent and dissociable fate decisions: proliferative competency (founding capacity) and lineage competency (potency). Founding capacity, which is a behavioural output of proliferative competency, is not biased or modified by either cell cycle position or cell cycle regulation during G2/M. This is in stark contrast to cell fate decisions pertaining to lineage, which are influenced by both cell cycle position and direct cell cycle governance during G2/M. Variation in cell cycle time may therefore serve as a mechanistic platform for creating heterogeneities within a relatively equivalent group of cells. Dissociation of founding capacity (proliferative competency) and potency (lineage competency) within the pluripotent population in vitro implores the field to redefine the population, our ideology of stem cells during early development, and how we functionally define them. Acknowledgement of a subpopulation of bona fide stem cells shifts our perception on the type and nature of cell fate decisions that can or have occurred. This shift in perception is relevant not only during normal development but also during processes such as regeneration and cellular reprogramming, which rely on the presence of plasticity within fate decisions that are characteristic of a stem cell.

Keywords: Cell Cycle
Cell Fate
Embryonic Stem Cell
Pluripotency
Stem Cell
Advisor: van der Kooy, Derek
Access to Versatile β-Cyclodextrin Scaffolds through Guest-mediated Mono-acylation

Cyclodextrins (CDs) are naturally occurring macrocyclic oligosaccharides comprised of α-1,4 linked glucose units. CDs are non-toxic and bio-compatible scaffolds. They have a conical structure with a hydrophobic inner cavity, allowing them to form stable and soluble inclusion complexes with a variety of hydrophobic guest molecules. Furthermore, CDs can be derivatized at the primary or secondary alcohols with a variety of functional groups. Compared to native CDs, derivatized CDs feature a broader range of applications including molecular recognition of small molecules and biomacromolecules, catalysis, supramolecular polymers and targeted drug/DNA delivery. This thesis addresses the hypothesis that highly functionalized cyclodextrins can be accessed via guest-mediated acylation reactions. This thesis explored the development of two methodologies to functionalize heptakis-[6-deoxy-6-(2-aminoethylsulfanyl)]-β-CD, a versatile, amine-functionalized scaffold. The key reaction developed was a selective mono-functionalization of heptakis-[6-deoxy-6-(2-aminoethylsulfanyl)]-β-CD via an acyl transfer reaction proceeding through a covalent-capture mechanism. This approach permitted the installation of a 5-mercaptopentanamide at the primary rim in two steps in high yields. The amine-orthogonal thiol was amenable to functionalization with maleimides or through disulfide exchange. The free thiol also served as a handle for immobilization of the mono-functionalized CD onto solid support for supported synthesis. The functionalization of the primary rim amines of the solid-supported CD, is a rapid and highly modular means to introduce diversity to this scaffold. The combination of these two methodologies afforded access to a library of peptide functionalized CD scaffolds which were modified with environmentally sensitive fluorophores to generate fluorescent receptors. These receptors were applied for the differential sensing of various bile salts, and are currently being investigated for the detection of elevated bile salts in human serum.

Advisor: Nitz, Mark
PREGNANCY, NEONATAL AND DISEASE OUTCOMES IN WOMEN WITH RELAPSING REMITTING MULTIPLE SCLEROSIS

Objective To compare pregnancy, neonatal and disease outcomes in women with Relapsing Remitting Multiple Sclerosis (RRMS) exposed to different therapeutic agents— natalizumab (Tysabri®) and Vitamin D. Methods Data from German and Canadian Multiple Sclerosis (MS) pregnancy registries was compared to evaluate neonatal and pregnancy outcomes in natalizumab exposed and unexposed groups. A healthy control group of pregnant women unexposed to teratogens was also utilized; primary outcome of interest was birth defects and miscarriage rates. For the Vitamin D study we first compared postpartum disease outcomes using Kaplan Meier and Cox Regression in a German (GER) cohort not supplementing with Vitamin D to a Canadian (CAN) cohort with Vitamin D supplementation in pregnancy; primary outcome of interest was time to disease resurgence in the postpartum period. We then evaluated neonatal outcomes in Canadians with high dose Vitamin D (>4000IU/day) in pregnancy to ones with lower intake. Primary outcome of interest was birth weight. Results There were no significant differences in birth defects or other adverse neonatal outcomes between the 101 natalizumab exposed, 78 disease matched, and 97 healthy controls. The rates of miscarriage were higher in both MS groups in comparison to the healthy controls. In the Vitamin D study, significantly more GERs used Disease Modifying Drugs (DMDs) in pregnancy and postpartum compared to CANs. There was no difference in disease resurgence between the two cohorts. Neonatal outcomes including birth weight did not differ significantly in the 29 women that exceeded 4000IU/day in pregnancy, compared to women that took lower doses. Conclusion Gestational exposure to either therapy, natalizumab or Vitamin D, is not associated with adverse outcomes. Larger studies are needed to investigate the longer duration of therapy with natalizumab and higher doses of Vitamin D >4000IU/day in pregnancy.

Keywords: Exposure
Multiple Sclerosis
Natalizumab
Neonatal Outcomes
Pregnancy
Vitamin D
Advisor: Ito, Shinya
Crisis-Opportunity, Liability-Asset: Governing Vacant Land Reuse in Cleveland, Ohio

This dissertation contributes to the literatures on post-2007 urban governance and urban greening by drawing novel connections between vacant land reuse, including urban agriculture, and the structures of urban governance. Through a historical analysis of housing vacancy, an institutional analysis of Cleveland’s community development industry’s response to the 2008 foreclosure crisis, and a case study of a vacant land reuse project, I argue that Cleveland’s community development industry shifted towards vacant land reuse and intervention to stabilize property values in response to the foreclosure crisis. This shift reveals a temporary resolution of the failure of subsidized housing construction following the crisis, but does not represent a significant departure from neoliberal community development. While the City has been effective in fostering certain forms of reuse, the heavy involvement of the community development industry and community foundations, combined with a local government facing fiscal pressure, has resulted in a constrained political field of opportunity for vacant land reuse. By devolving the labor of lot maintenance onto residents and continuing to prioritize traditional economic development, many of the possibilities for using vacant land reuse for social and environmental justice have been limited. However, I also show that the incorporation of vacant land reuse within the community development industry in Cleveland was the outcome of a process of weak contestation, negotiation, and path dependency, not a simple imposition of neoliberal ideology. Additionally, my findings concerning reuse projects on the ground reveals the shortcomings of relying on under-resourced resident labor and shows cracks in the hegemony of private property and market logics in high-abandonment neighborhoods. My findings point to the importance of studying how greening projects are interacting with preexisting structures of urban governance. It suggests that the commodification of land and market-based community development places limits on vacant land reuse that directly benefits residents and works towards environmental and food justice.

Keywords: community development
political economy
urban agriculture
urban governance
urban greening
vacant land
Advisor: Wakefield, Sarah
Design and Development of a Force Generator Based on Magnetorheological Fluid

A force generator system that provides force information to a practitioner performing remotely controlled robotic surgery based on magnetorheological fluid (MRF) was developed. The actuator provides the operator a wide range of force corresponding to various tissue properties. The actuator enhances the percutaneous feeling of a surgeon interacting remotely with tissues in robotic bone biopsy. The force profile of bone drilling was characterized and modeled. The range of the force and operational bandwidth required for drilling operations was determined. The model characterizes the axial forces recorded while drilling perpendicular to the long axis of femurs in different animal specimens. The findings were used to design an actuator suitable for surgical applications, principally bone biopsies. To develop the actuator prototype, a magnetic circuit was designed and an appropriate MRF was selected. The magnetic circuit was validated by magnetostatic analysis. The final design of the actuator prototype was developed based on experimental observations. The actuator produces an output force appropriate for bone biopsy (high range of forces). The hysteretic behavior of the proposed actuator was modeled by characterizing the relationship between the input and output measurements. To construct a model of the actuator, a master-slave robotic biopsy system was setup and used to obtain input and output measurements for various animal tissues. These measurements were then used as estimators and validators of a nonlinear Hammerstein-Wiener (H-W) model. The nonlinear model was verified by comparing the measured data with the simulation results under various test conditions. The H-W model can predict the behavior of the MRF actuator with high precision. The H-W model was used to eliminate hysteresis in a closed-loop control system. Experiments were performed to demonstrate the efficacy and advantages of the H-W modeling and control technique. The H-W control tracked the input signal, recorded from various tissues via a slave robot, while compensating for magnetic hysteresis, to achieve optimal performance. In conclusion, the MRF-based actuator designed in this study, with its control system, can be used in surgical robotic operations that involve a high range of force measurements.

Keywords: black-box modeling
bone biopsy
control
Magnetorheological Fluid
telerobotic surgery
Advisor: Goldenberg, Andrew A
Drake, James M
Analysis and Interpretation of Lower Limb Mechanomyographic Signals in Human Gait

This thesis investigates the patterns of accelerometer-based MMG in the lower extremities during gait. To characterize dynamic muscle activity, we measured lower limb mechanomyography (MMG) and electromyography (EMG) during over ground and treadmill locomotion in typically developing youth and adults. First, MMG activity was validated against coincidental EMG activity and detection parameters were optimized for each muscle using a particle swarm optimization (PSO) algorithm. The mean balanced accuracy between MMG muscle activity and concurrent EMG activity was >75% for all muscles sites except the gastrocnemius, where concurrent activity was only observed about 55% of the gait cycle. These findings suggest that during dynamic movements, electrical muscle activity is not directly followed by mechanical activity of the muscle fascicles since some muscles, like the gastrocnemius, contract isometrically and lengthen in the absence of electrical activity. To understand how mechanical activity is coordinated between the lower limb muscles, mechanical synergies were then extracted using non-negative matrix factorization (NMF) analysis and compared against neural synergies. For treadmill walking and running, mechanical muscle activity yielded lower dimensional synergies than did corresponding electrical activity. Furthermore, mechanical synergies contained overwhelming co-activity of muscles, possibly reflecting the active and passive lengthening of muscle fascicles as joints move to complete a motor task. These synergies can be used to track therapy progression by analyzing how mechanical patterns change with MMG biofeedback. Based on MMG patterns observed during typical gait, a Smartphone application, GaitTool App, was developed as an at-home gait therapy tool. MMG was recorded at the tibialis anterior and the lateral gastrocnemius using wearable sensors that transmit packets of MMG data to an Android device via Bluetooth. MMG data were analyzed for spatiotemporal features and triggered auditory feedback in the form of a cadence-driven rhythmic auditory stimulus to allow for anticipatory movement preparation and execution. The sonification of the alignment of MMG peaks provided an aural cue to differentiate between typical and atypical gait patterns.

Keywords: electromyography
gait
mechanomyography
muscle activity
rehabilitation
wearable technology
Advisor: Chau, Tom
Considerations for the Implementation of Caregiver Education and Support Programs in a Regional Stroke System

Family caregivers need education and support to care for themselves and their loved ones but caregiver programs have not been formally implemented in the Canadian healthcare system. The overall objective of this research was to explore the organizational/system perspective regarding the implementation of caregiver education and support programs into standard clinical practice in a regional stroke system. This research had 2 phases: 1) Key Informant Study and 2) Qualitative Descriptive Study. The objective of the first phase was to gain insight from key informants from the regional stroke system, health authorities, and government to identify organization and system level considerations associated with implementing stroke caregiver programs to inform data collection and participant groups to include in a large-scale qualitative descriptive study of the Ontario Stroke System. Findings from 12 participants suggested program implementation requires consensus on the need for caregiver programs in the health care system, evidence to support implementation, and engagement of stakeholders. Findings indicated specific system and program level considerations to explore and participant groups to include in the large-scale qualitative descriptive study. There were 72 participants in the qualitative descriptive study. Findings suggested program implementation requires establishing the need for caregiver programs in the health care system, incorporating caregiver programs into the system of care, resolving the uncertainty regarding ownership and responsibility for implementation, and addressing regional variations. Program level considerations included evidence to support local implementation, personnel requirements, barriers related to workflow processes and integration with current practice and existing workflow processes. Implementing caregiver programs in a regional stroke system is a multi-faceted issue that requires a concerted effort from stakeholders across the health care system. This research can be used to inform the development of implementation strategies for such programs to ensure that family caregivers receive the support they need.

Advisor: Cameron, Jill I.
Jaglal, Susan B.
Requirement for HEB in the Specification of Fetal IL-17-producing γδ T cells

IL-17-producing γδ T (γδT17) cells are critical components of the innate immune system, and serve as an early and important source of IL-17 in host protective immune responses and autoimmunity. The complexity of the pathways that drive the development and functional programming of γδ T cells has become increasingly evident in recent years, yet they remain poorly understood. This thesis focuses on the gene network that drives the development of a fetal-derived subset of γδT17 cells which populates various lymphoid and mucosal tissues in mice. I have identified a newly defined subset of CD24-CD73- γδT17 cells, which are comprised primarily of fetal-derived Vγ6+ and Vγ4+ RORγt+ γδ T cells. I found that a functional bifurcation occurs at the CD24+CD73- stage, which then resolves in a Vγ-chain specific manner. RORγt- Vγ5 and Vγ1 cells develop along CD24+CD73+ and CD24-CD73+ stages to become γδT1s, and RORγt+ Vγ6 and Vγ4 cells directly downregulate CD24 to become CD24-CD73- γδT17 cells. I showed that HEB (Tcf12) is required for the generation of these CD73- γδT17 cells. HEB is required in the immature CD24+CD73- γδ T cells for the expression of Sox4, Sox13, and Rorc, and these genes are repressed by acute expression of the HEB antagonist Id3. I further demonstrated that HEB can directly regulate Sox4 and Sox13 transcription. HEB-deficiency also impacts mature CD73+ γδ T cells, which are defective in RORγt expression and IL-17 production. Additionally, the fetal HEB-/- Vγ chain repertoire is altered, and peripheral Vγ4 γδ T cells are largely restricted to the IFNγ-producing phenotype. Therefore, I have identified several HEB-dependent pathways for the development of CD73+ and CD73- γδT17 cells, and provided mechanistic evidence for the control of the γδT17 gene network by HEB.

Keywords: Fetal thymocytes
gammadelta T cell
gamma delta T cell
gd T cell
HEB
IL-17
Advisor: Anderson, Michele K
Ruthenium-Based Hydrogenation and Frustrated Lewis Pair Chemistry

Since the discovery of catalytic hydrogenation, the field of transition metal-based hydrogenation catalysis has grown significantly. Recently, main group systems have demonstrated the capability to perform some of the same catalytic processes. Frustrated Lewis pairs (FLP), the combination of sterically encumbered Lewis acids and Lewis bases, are able to activate a variety of small molecules. The research presented in this thesis investigates main group and transition metal-based catalytic hydrogenation, as well as stoichiometric transformations with main group systems. A variety of ruthenium N-heterocyclic carbene (NHC) complexes were generated with polyethylene glycol (PEG) on the NHC to impart water-solubility. These hydrogenation catalysts were used to hydrogenate nitrile butadiene rubber (NBR) to hydrogenated nitrile butadiene rubber (HNBR). The PEG lengths had minimal effect on the conversion of NBR in solution phase. For the hydrogenation of NBR latex, a correlation was observed between the PEG length and the activity. A family of phosphinimines with different steric and electronic properties was synthesized from the Staudinger reaction between alkynyl-phosphines and azido-phosphine-boranes. Cyclization of these products can be induced thermally or by the addition of catalytic amounts of B(C6F5)3. Upon cyclization, a net trans-hydroboration was observed on the exocyclic alkene. A novel geminal boron-sulfur FLP was synthesized from the hydroboration of sulfur-alkynes. These systems demonstrated FLP-type chemistry such as the activation of terminal alkynes. Interestingly, the frustration was a result of the steric conflict between the tert-butyl substituent on the carbon and the p-tolyl substituent on the Lewis basic sulfur. This FLP-type reactivity can altered upon isomerization of the complex, forming the classical Lewis pair adduct. Finally, metal-free transformation of 3-ethylidene-6-vinyltetrahydro-2H-pyran-2-one was investigated. The Lewis acid B(C6F5)3 was shown to catalytically hydrogenate the allyl functionality of the substrate, as well as catalytic hydrosilylation of the conjugated alkene.

Keywords: Frustrated Lewis Pair
Advisor: Stephan, Douglas W