VictorJuiz/thesis huggingface dataset:
Time-dependent Photomodulation of a Single Atom Tungsten Tip Tunnelling Barrier

There has been much work on electron emission. It has lead to the concept of the photon and new electron sources for imaging such as electron microscopes and the rst formulation of holographic reconstructions [1-6]. Analytical derivations are important to gain physical insight into the problem of developing better electron sources. However, to date, such formulations have su ered by a number of approximations that have masked important physics. In this thesis, a new approach is provided that solves the Schrodinger wave equation for photoemission from a single atom tungsten tip barrier or more generally, for photoemission from a Schottky triangular barrier potential, with or without image potential e ects. We describe the system, then introduce the mathematical derivation. We conclude with the applications of the theory.

Keywords: Photoemission
Tungsten
general solution to partial differential equations
Schrodinger equation
Field emission
Fowler-Nordheim
photomodulation
solving complex band structure
Advisor: Miller, Dwayne
Syntaxin-3 Regulates Biphasic Glucose Stimulated Insulin Secretion in the Pancreatic Beta Cell

Our study aims to investigate the role of Syntaxin-3 in glucose stimulated insulin secretion (GSIS) and how it regulates the recruitment to plasma membrane and/or exocytotic fusion of insulin granules. We examined endogenous Syn-3 function by down-regulating its expression using siRNA/lenti-shRNA, which impaired GSIS. Although Syn-3 depleted cells showed no change in the number and fusion of docked granules, there was a reduction in newcomer granules and their subsequent exocytotic fusion. We then examined the effects of overexpressing Syn-3-WT, which enhanced biphasic GSIS. Since open conformation (OF) Syn-1A was reported to enhance exocytosis by promoting SNARE complex formation, we constructed OF Syn-3. Exogenous OF Syn-3 had no effect on secretion as it is unable to be trafficked to insulin granules. Taken together, we conclude that Syn-3 facilitates mobilization of newcomer insulin granules to the plasma membrane, to contribute to both first and second phase of GSIS in pancreatic beta cells.

Keywords: Insulin Secretion
Syntaxin
SNAREs
Exocytosis
Advisor: Gaisano, Herbert Young
Interaction Between the Effects of Preparation Method and Variety on the Glycemic Index of Novel Potato Varieties

As part of a project to see whether potatoes with a low glycemic-index (GI) could be developed through plant breeding, the GI values of 4 new potato varieties differing in starch structure was determined in 3 studies over 2 years in human subjects. Since cooking and cooling affects starch structure the potatoes were studied both freshly cooked (boiled) and cooled. The first study showed that cooling reduced the GI of two varieties by 40-50% but had no effect in the others (treatment × variety interaction, p=0.024), an effect which was confirmed in study 2. Differences in GI were readily explained by differences in starch structure or in-vitro digestion rate. Carbohydrate malabsorption increased from 3 to 5% upon cooling, not enough to account for the reduced GI. It is concluded that the effect on GI of cooling cooked potatoes varies in different varieties. Further research is needed to understand the mechanism.

Keywords: Glycemic Index
Potatoes
In-vivo Digestability
Starch
Advisor: Wolever, Thomas M. S.
Investigating the Process of Cement Line Maturation on Substrate Surfaces with Submicron Undercuts

The cement line is the first mineralized matrix deposited on an implant surface during contact osteogenesis forming the bone/implant interface. The hypothesis underlying the present project was that non-collagenous cement line proteins must be deposited into the submicron undercuts on substrate surfaces prior mineralization. In vitro osteogenic cultures were used to grow bone nodules on Thermanox® coverslips modified with calcium phosphate nanocrystals, creating an undercutted surface. Electron microscopy was used to observe cement line formation. BSP immunogold labelling was used to determine if the cement line organic matrix is deposited within undercuts prior mineralization. The results showed the deposited bone nodules, and on test coverslips the deposited cement line was thicker and evenly distributed than control. Furthermore, positive BSP labelling was found within the undercuts prior to cement line mineralization. Thus, it can be concluded that cement line proteins are deposited into submicron undercuts on substrate surfaces prior to mineralization.

Keywords: Cement Line
Bone Implant Interface
Submicron Undercuts
Bone-bonding
Advisor: Davies, John Edward
Investigating the Roles of Homeobox Containing Transcription Factors Iroquois 3/5 in Mammalian Heart Development and Electrophysiology

Iroquois homeobox (Irx) family members, a group of highly conserved homeodomain containing transcription factors, are involved in the patterning and the proper functions of vertebrate organs. They can act as transcriptional activators or repressors in a context-dependent manner. Preliminary data indicated that Irx3 and Irx5 are functionally redundant during cardiac morphogenesis, and they physically interact with other cardiac transcription factors. At E14.5, outflow tract septation failure and ventricular septation failure were observed in Irx3/5DKO mouse hearts. Loss of Irx3/5 in neural crest and endothelial cell lineages led to outflow tract septation failure and ventricular septal defect. In adult mice, Irx3 is expressed in the atrioventricular conduction system, and loss of Irx3 leads to slower ventricular conduction velocity. qRT-PCR analysis and immunofluorescence staining revealed that the expression of gap junction proteins, Cx40 and Cx43, are affected by the loss of Irx3. Over-expression of Irx3 and a dominant repressor form of Irx3, Irx3-EnR, resulted in Cx40 upregulation, indicating that Irx3 acts as an indirect positive regulator of Cx40. Irx3-EnR over-expression in vivo resulted in postnatal onset of atrial enlargement, ventricular hypertrophy, and conduction failure. Taken together, this study demonstrates the significance of Irx3/5 in both cardiovascular development and cardiac electrophysiology.

Keywords: Iroquois
homeobox
heart development
cardiac electrophysiology
cardiac transcription factor
Advisor: Hui, Chi-chung
Precoding and Resource Allocation for Multi-user Multi-antenna Broadband Wireless Systems

This thesis is targeted at precoding methods and resource allocation for the downlink of fixed multi-user multi-antenna broadband wireless systems. We explore different utilizations of precoders in transmission over frequency-selective channels. We first consider the weighted sum-rate (WSR) maximization problem for multi-carrier systems using linear precoding and propose a low complexity algorithm which exhibits near-optimal performance. Moreover, we offer a novel rate allocation method that utilizes the signalto- noise-ratio (SNR) gap to capacity concept to choose the rates to allocate to each data stream. We then study a single-carrier transmission scheme that overcomes known impairments associated with multi-carrier systems. The proposed scheme utilizes timereversal space-time block coding (TR-STBC) to orthogonalize the downlink receivers and performs the required pre-equalization using Tomlinson-Harashima precoding (THP).We finally discuss the strengths and weaknesses of the proposed method.

Keywords: Resource Allocation
Precoding
MIMO-OFDMA
Stream Rate Allocation
Time-Reversal Space-Time Block Coding
Tomlinson-Harashima precoding
Weighted Sum-Rate MAximization
Weighted MMSE Minimization
Advisor: Lim, Teng Joon
Doostnejad, Roya
The Hormonal Regulation of Kisspeptin and Neuropeptide Y Hypothalamic Neurons

Kisspeptin (encoded by Kiss1) is a hypothalamic neuropeptide that is directly regulated by sex steroids and directly stimulates gonadotropin-releasing hormone (GnRH) neurons. Kisspeptin cell models were established in order to facilitate future molecular analysis of kisspeptin. mHypoA-51 and mHypoA-63 cell lines were found to express kisspeptin, estrogen receptor α and β, substance P, but not tyrosine hydroxyase. Furthermore, estrogen decreased Kiss1 expression in both cell lines. Based on these results, it was concluded that mHypoA-51 and mHypoA-63 are representative of arcuate kisspeptin neurons. Accumulating evidence also indicates that kisspeptin indirectly stimulates GnRH neurons through afferent neurons. Kisspeptin receptor expression was detected in native neuropeptide Y (NPY) neurons. Using the mHypoE-38 cell line, kisspeptin was found to directly regulate NPY mRNA expression and secretion via the ERK1/2 and p38 MAPK pathways. This is the first evidence that kisspeptin directly stimulates NPY neurons to potentially exert indirect effects on GnRH neurons.

Keywords: kisspeptin
neuropeptide Y
estrogen
hypothalamus
immortalized cell lines
Advisor: Belsham, Denise
Global Position Effects on the Epigenetics of Variegated Lentiviral Vector Expression in Embryonic Stem Cells

Lentivirus efficiently transduce stem cells, however are notably silenced in embryonic stem cells (ESC). Provirus can be silent, expressing, or variegated when clonal single copy ESCs spawn daughters that revert expression despite containing identical integration sites (IS) indicating epigenetic regulation. In the silent state, variegated provirus are bound by H1 and MeCP2, where H1 compensates for MeCP2 binding in DNA methylation null ESCs, consistent with a model of heterochromatin formation dependent on concentrations of its constituent components. ESC Variegation was hypothesized to result from spreading of nearby heterochromatin. Global IS analysis indicates Variegated IS favour gene deserts, repeat clusters, and LINEs while Expressers prefer gene density with stable modest expression and SINEs. Chromatin data does not support a role for the spread of heterochromatin possibly a consequence of the dynamic/dispersed nature of ESC heterochromatin. Variegation thus may depend on stochastic chromatin regulation by pluripotency factors at proximal genome organizing repeats.

Keywords: Epigenetics
Retrovirus
Embryonic Stem Cells
Variegation
Viral Expression
Chromatin Structure
Lentivirus
Integration Site
Gene Therapy
Bioinformatics
Advisor: Ellis, James
Effects of Biodiesel Fuelling on Diesel Particulate Matter

Diesel particulate matter (PM) produced from Ultra Low Sulfur Diesel (ULSD), Soy-derived B20 and Animal fat-derived B20 was collected at two engine operating conditions. Gravimetric analysis showed the PM emissions to depend on both fuel and engine operating condition. B20 fuels exhibited higher PM emissions at low load conditions, but lower PM emissions under high load conditions. The differences between the operating conditions were less significant for B20 fuels than for ULSD. Elemental Carbon analysis revealed the B20 PM to contain greater proportions of organic carbon, which may improve diesel particulate filter (DPF) regeneration. Finally, TEM images showed considerable differences between ULSD and B20 soot at low engine loads. The B20 soot displayed a more disordered arrangement of graphene layers. At higher loads, the differences are subtle, but the B20 PM still displayed a more amorphous structure. There was little difference between the Soy and Animal fat-derived B20 soot.

Keywords: Biodiesel
Biofuels
Particulate Matter
Diesel
Diesel Particulate Filter
Microstructure
Regeneration
Advisor: Wallace, James S.
Evans, Greg J.
The Transformation of Landscapes in Southwest Montréal and Identity Formation During the Quiet Revolution

In this thesis I demonstrate how the social and physical construction of spaces in Montréal‘s CBD during the Quiet Revolution marginalized working-class, inner-city manufacturing districts. To address this research question, I work across a variety of secondary sources and employ census data and reports to analyze demographic changes as well as other indices that illustrate the impact of local economic restructuring. In order to understand identity formation that is related to yet distinct from the mechanisms of capital, I examine archival documents that trace the urban growth regime’s nationalist-inflected vision of high-modernity that was inscribed onto the city’s landscape. I focus on the appropriation of landscapes in working-class Southwest Montréal. I situate these landscape transformations in a longer history of class formation in which a colonized Francophone bourgeoisie attempted to reverse its socioeconomic circumstances that were partly a consequence of the British conquest.

Keywords: historical geography
Montréal
Québec Studies
Canadian Studies
urban planning
Advisor: Farish, Matthew
Supporting Biomimetic Design by Categorizing Search Results and Sense Disambiguation, with Case Studies on Fuel Cell Water Management Designs

Biology is a good source of analogies for engineering design. One approach of retrieving biological analogies is to perform keyword searches on natural-language sources such as books, journals, etc. A challenge in retrieving information from natural-language sources is the potential requirement to process a large number of search results. This thesis describes two methods on improving the relevancy of the search results. The first method is inserting metadata such as part- of-speech, word sense and lexicographical data for each word in a natural-language. The second method is categorizing the search results, using WordNet relationships and Wikipedia structures as ontologies. Although this research is still exploratory, initial qualitative observations demonstrate successful identification and separation of biological phenomena relevant to either desired functions or desired qualities. The benefits of embedding metadata are demonstrated through a case study on the redesign of a fuel cell bipolar plate. A prototype was constructed with ability to passively prevent prolonged catastrophic flooding.

Keywords: Biomimetic
Fuel Cell
Advisor: Shu, Lily H.
Wallace, James S.
Correlating Neuropsychiatric Symptoms with Regional Beta-Amyloid Load in the Alzheimer’s Disease Brain Using [11C]SB-13 Positron Emission Tomography

Correlations between neuropsychiatric symptoms and beta-amyloid (Aβ) burden in specific brain regions in living Alzheimer’s disease (AD) patients remain to be elucidated. Ten mild AD patients underwent MR and [11C]SB-13 PET imaging. Neuropsychiatric symptoms were quantified with the Neuropsychiatric Inventory (NPI). NPI-depression/dysphoria, -apathy, -agitation/aggression, -anxiety, and -appetite/eating disorders scores were hypothesized to correlate with Aβ burden in particular brain regions. Pearson’s correlation coefficient revealed that depression/dysphoria scores positively correlated (p<0.05) with standardized uptake values (SUVs) from left medial temporal lobe (r=0.67), and agitation/aggression correlated with SUVs from bilateral anterior cingulate (right, r=0.71; left, r=0.78), temporal (right, r=0.71; left, r=0.75), parietal (right, r=0.77; left, r=0.81), and dorsolateral prefrontal cortex (right, r=0.74; left, r=0.73). However, NPI scores did not significantly correlate with better estimates of Aβ burden that use the cerebellum as reference region. Overall, our results confirm the lack of association between Aβ burden and neuropsychiatric symptoms reported in autopsy studies.

Keywords: Alzheimer's Disease
beta-amyloid
behaviour
neuropsychiatric symptoms
neuroimaging
positron emission tomography
PET
SB-13
Advisor: Verhoeff, Nicolaas Paul L. G.
Reekum, Robert van
Technology Transfer Agreements Containing Tacit Knowledge

In the world we live in transfer of technology is of a great importance. The primary means of technology transfer is by imitating and making copies. However, there are cases where copying is impossible or prohibited. In those cases, technology transfer involves contracting. Those agreements may contain both transfer of codified and tacit knowledge. Technology transfer agreements, containing tacit knowledge, have special characteristics due to the presence of the know-how, and to the need to transfer it. In this paper, I explore the special measures of technology transfer agreements containing tacit knowledge. I explain why general contract law does not address properly those challenges. I elaborate on the current solutions to these problems, adopted both by the parties and by legislatures, as well as their difficulties. Eventually, I propose possible solutions, either to the legislature or to the judiciary, in order to address those issues in a better way.

Keywords: know-how
tacit knowledge
technology transfer
codified knowledge
know how
tacit
Advisor: Katz, Ariel
Evaluating the Relative Effectiveness of Two Supplemental Foods for the Treatment of Moderate Acute Malnutrition in Children 6 to 60 Months of Age in Southern Ethiopia

The purpose of this cluster-randomized equivalence trial was to investigate the effectiveness of two supplemental foods in children with moderate malnutrition by comparing: (i) time to recovery by survival analysis, and (ii) recovery rates (after 16 weeks of treatment). A total of 2,600 children 6-60 months of age were randomized by cluster (district) to receive 16 weeks of conventional (Corn-Soya Blended flour, CSB) or intervention (Ready-to-Use Supplemental Food, RUSF) foods. Overall, time to recovery from malnutrition (mean 74 days) and recovery rates (mean 76%) were equivalent with both foods. The time to recovery outcomes were equivalent, independent of location, whereas the recovery rate in children receiving CSB was significantly higher in the more food insecure southern region. Intra-household food sharing was significantly higher in the CSB group compared to RUSF. Overall, the response to the two different supplemental foods was equivalent for the treatment of moderately malnourished children in Ethiopia.

Keywords: malnutrition
treatment food
ethiopia
united nations
RUSF
CSB
Advisor: Zlotkin, Stanley H.
Paraesthesia Following Dental Local Anaesthetic Administration in the United States

Background: Several studies have suggested that the likelihood of paraesthesia may depend on the local anaesthetic (LA) used. The purpose of this study was to analyze reports of paraesthesia among dental LAs used in the U.S. Methods: Reports of paraesthesia involving LAs between November 1997 through August 2008 were obtained from the U.S. Food and Drug Administration Adverse Event Reporting System. Chi-Square analysis compared expected frequencies, based on U.S. LA sales data, to observed reports of oral paraesthesia. Results: During the study period 248 cases of paraesthesia following dental procedures were reported. Most (94.5%) cases involved mandibular nerve block. The lingual nerve was affected in 89.0% of cases. Reports involving 4%-prilocaine and 4%-articaine were 7.3-times and 3.6-times, respectively, greater than expected (χ2, p<0.0001) based on LA usage by U.S. dentists. Conclusions: Consistent with previous reports, these data suggest that paraesthesia is more common following use of 4% LA formulations.

Keywords: Paraesthesia
Articaine
Prilocaine
Inferior alveolar nerve
Lingual nerve
Local Anaesthetics
Dentistry
Advisor: Haas, Daniel
Neural Correlates of Driving in a Virtual Reality Environment

Driving is a cognitively complex task, yet the areas of the brain involved in driving are not well understood. This thesis investigates the neural correlates of driving using functional magnetic resonance imaging and driving simulations with custom built driving hardware (steering wheel and foot pedals). The feasibility of driving in fMRI is first investigated, and a methodology is described to minimize head motions. Next, the functional neuroanatomical correlates of driving tasks of varying complexity are explored. Simple tasks such as straight driving activate areas of the brain related to motion, spatial navigation and coordination. Complex tasks are found to recruit additional areas of the brain, including areas of higher cognitive function such as the prefrontal cortex. Developing a better understanding of the areas involved in different driving tasks is an important first step in understanding the neural basis of driving skill and safe driving.

Keywords: driving
fMRI
virtual reality
Advisor: Schweizer, Tom
Quality of Life in Pediatric Patients with Intestinal Failure on Home Parenteral Nutrition

Introduction: Medical advances have resulted in reduced mortality of pediatric patients with Intestinal Failure. Consequently, more patients go home on parenteral nutrition (PN) for extended durations. This time-consuming and complicated therapy necessitates persistent vigilance in monitoring and response to potential life-threatening side effects. These issues may impact quality of life (QOL) for patients, caregivers and families. Methods: This observational, cross-sectional, mixed-methods analysis of multidimensional QOL used a quantitative battery assessment and a qualitative focus group. Questionnaire results were compared to published norms, published small bowel transplant (SBTx), and institutional SBTx patients. Results: Home PN proxy assessments scored children lower than published norms but similar to SBTx. The child self-reports were similar to both normative and SBTx populations, except lower general and overall health. Generic questionnaires did not capture disease-specific issues. Conclusion: QOL is compromised in children on home PN and caregivers compared to norms but is similar to SBTx.

Keywords: Quality of Life
Pediatrics
Intestinal Failure
Parenteral Nutrition
Functional Status
Home Parenteral Nutrition
Child Health Questionnaire
PedsQL
Focus Group
Mixed Methods
Nutrition
Battery Assessment
CHQ
Pediatric Quality of Life Questionnaire
Advisor: Wales, Paul W.
Active Flow Control Using Synthetic Jet Actuation

The influence of periodic excitation from synthetic jet actuators, SJA, on boundary layer separation and reattachment over a NACA 0025 airfoil at a low Reynolds number is studied. All experiments reported are performed in a low-turbulence recirculating wind tunnel at a Reynolds number of 100000 and angle of attack of α=5◦. Mounted below the surface of the airfoil, the SJA consists of four 32.8 mm diameter piezoelectric ceramic diaphragms positioned in a single row. Flow visualization results show a reattachment of the boundary layer and a significant reduction in wake structure. Velocity proﬁles downstream of the trailing edge and the results show a drastic reduction in wake size as excitation is introduced. A spectral analysis was conducted in the wake region and showed the presence of vortex shedding at a frequency of 22 Hz. When excitation was applied at 935 Hz and 250 Vp−p, the shedding frequency shifted to 50Hz.

Advisor: Sullivan, Pierre E.
Nonlinear Parametric Generation in Birefringent Poled Fibers

Conventional step-index silica fibers do not possess a second-order optical nonlinearity due to symmetry concerns. However, through the process of poling, the generation of a frozen-in DC field EDC, and in turn, a non-zero second-order nonlinearity ?(2) =3?(3)EDC, can be created in optical fibers. In this thesis, I measure the individual ?(2) tensor elements of birefringent periodically poled fiber via second-harmonic generation and sum-frequency generation experiments. The symmetry of the ? (2) tensor is consistent with that of the ?(3) for isotropic media. This is the first study that characterizes all the ? (2) tensor elements in birefringent poled fiber. Furthermore, I investigate the intermix of the ?(2) tensor elements by twisting the fiber, which results in the generation of new second-harmonic signals not observed in untwisted fiber. The conversion efficiencies and spectral positions of these new signals can be varied by twisting the fiber.

Keywords: Nonlinear Optics
Optical Fibers
Second-Harmonic Generation
Advisor: Qian, Li