Tissue classification from electric impedance spectroscopy for haptic feedback in minimally invasive surgery

Haptic feedback is missing in teleoperated surgical robots creating a sensory disconnect from the surgeon and their patient. This thesis proposes using the electric impedance of tissues, instead of the traditionally used mechanical impedance, to develop haptic feedback for surgical robots. Electric impedance spectroscopy (EIS) and a modified surgical needle were successfully able to measure the electric impedance for gel-based phantoms, ex-vivo tissue, and freshly excised organs. Processes for fitting the electric impedance of these tissues to the double-dispersion Cole model were developed including stochastic and deterministic approaches. The tissues were classified with least square error, k-Nearest Neighbour and Na??ve Bayes using the measured electric impedance and the extracted model parameter values. The thesis culminates in applications of using EIS as part of implementing vibrotactile and force feedback applications involving sets of user trials to validate its effectiveness in identifying the tissue through haptic feedback

Ride the wave : investigating the continuum of teacher mental health through multiple lenses

The mental health of teachers impacts the entire school community. However, to our knowledge, the mental health of teachers has not been investigated from multiple lenses. These lenses include research literature, teacher narratives of their lived experiences, human resource professionals interfacing with teachers, and ourselves as research practitioners. We identify current understandings of teacher mental health among teachers and other educational professionals, determine current preventative and support measures available, and suggest recommendations for future research. The following four questions guided our study: How is mental health defined as it relates to teachers and teaching? What mental health concerns commonly affect teachers? What are some opportunities or challenges facing teachers in accessing mental health resources? What does a mentally healthy school look like? We conducted a literature review and in-person interviews with human resource and organization experts to help answer the questions. Our findings suggest specific risk factors, common mental health issues, coping strategies, challenges and opportunities, and administrators’ roles in promoting or harming the mental health of teachers. Our findings demonstrate teacher mental health has implications beyond the individual teacher. It has the potential to impact student achievement, collegial and home relationships, and the entire school community. Our findings suggest a need for specific training teacher and administrator in the areas of mental health literacy, building trusting relationships, identifying psycho-social risk factors, resiliency training, promoting “work/home” balance, and realistic work conditions. Overall, we found there is a need for cooperation and collaboration between management, teachers, and the union in effectively addressing teacher mental health.Education, Faculty ofEducational Studies (EDST), Department ofUnreviewedGraduat

Entrapment of Hydrophilic and Hydrophobic Molecules in Beads Prepared from Isolated Denatured Whey Protein

The oral route of administration is by far the most convenient route, especially in the treatment of chronic conditions. However, many therapeutics present formulation difficulties which make them unsuitable for oral delivery. Recently, we synthesized a denatured whey protein isolate (dWPI) bead entrapped with insulin. Our present goal was to assess the suitability of this delivery system to the delivery of other potential molecules, both hydrophilic and hydrophobic. Beads of 1.2–1.5 mm in diameter were entrapped with four payloads representing a range of solubilities. The water-soluble payloads were sodium fluorescein (SF) and FITC dextran 4000 Da (FD4), while the hydrophobic ones were Fast Green and curcumin. Encapsulation efficiency (EE) was 73%, 84%, 70%, and 83% for SF, FD4, Fast Green, and curcumin-loaded beads, respectively. The corresponding loading capacity for each bead was 0.07%, 1.1%, 0.75%, and 1.1%, respectively. Each payload produced different release profiles in simulated gastric fluid (SGF) and simulated intestinal fluids (SIF). SF released steadily in both SGF and SIF. FD4 and curcumin release was not substantial in any buffers, while Fast Green release was low in SGF and high in SIF. The differences in release behaviour were likely due to the varying properties of the payloads. The effect of proteolysis on beads suggested that enzymatic degradation of the whey bead may promote payload release. The beads swelled rapidly in SGF compared to SIF, which likely contributed to the release from the beads, which was largely governed by solvent diffusion and polymer relaxation. Our results offer a systematic examination of the behaviour of hydrophilic and hydrophobic payloads in a dWPI delivery system. These beads may be further designed to orally deliver poorly permeable macromolecules and poorly soluble small molecules of pharmaceutical interest

BK-type calcium-activated potassium channels: coupling of metal ions and voltage sensing

Ion channels and lipid phosphatases adopt a transmembrane voltage sensor domain (VSD) that moves in response to physiological variations of the membrane potential to control their activities. However, the VSD movements and coupling to the channel or phosphatase activities may differ depending on various interactions between the VSD and its host molecules. BK-type voltage, Ca2+ and Mg2+ activated K+ channels contain the VSD and a large cytosolic domain (CTD) that binds Ca2+and Mg2+. VSD movements are coupled to BK channel opening with a unique allosteric mechanism and are modulated by Ca2+ and Mg2+ binding via the interactions among the channel pore, VSD and CTD. These properties are energetically advantageous for the pore to be controlled by multiple stimuli, revealing the adaptability of the VSD to its host molecules and showing the potential for intracellular signals to affect the VSD in order to modulate the function of its host molecules