Theses, Dissertations, and other Required Graduate Degree Essays

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This collection contains digitized SFU theses except for those theses submitted within the last 12 months. If you cannot find the thesis you are looking for please search Recently Submitted Theses as it may be a recently submitted thesis and thus not yet available in Summit.

Development of a microfluidic platform for size-based enrichment and immunomagnetic isolation of circulating tumour cells

Date created: 
2017-08-16
Abstract: 

Cancer is a leading cause of death worldwide. Efforts to improve the longevity and quality of life of cancer patients are hindered by delays in diagnosis of tumours and treatment deficiency, as well as inaccurate prognosis that leads to unnecessary or inefficient treatments. More accurate biomarkers may address these issues and could facilitate the selection of effective treatment courses and development of new therapeutic regimens. Circulating tumour cells (CTCs), which are cancer cells that are shed from tumours and enter the vasculature, hold such a promise. Therefore, there is much interest in the isolation of CTCs from the blood. However, this is not a trivial task given the extreme scarcity of CTCs in the circulation. In this thesis, the development of a microfluidic immunomagnetic approach for isolation of CTCs is presented. First, the design, microfabrication, and experimental evaluation of a novel integrated microfluidic magnetic chip for sensitive and selective isolation of immunomagnetically labelled cancer cells from blood samples is reported. In general, to ensure the efficient immunomagnetic labelling of target cancer cells in a blood sample, an excessive number of magnetic beads should be added to the sample. When an immunomagnetically labelled sample is processed through the chip, not only cancer cells but also free magnetic beads that are not bonded to any target cells would be captured. The accumulation of these beads could disrupt the capture and visual detection of target cells. This is an inherent drawback associated with immunomagnetic cell separation systems and has rarely been addressed in the past. Therefore, the design, microfabrication, and characterization of a microfluidic filter for continuous size-based removal of free magnetic beads from immunomagnetically labelled blood samples is presented next. Connected in tandem, the two chips developed in this work form a microfluidic platform for size-based enrichment and immunomagnetic isolation of CTCs. Preclinical studies showed that the proposed approach can capture up to 75% of blood-borne prostate cancer cells at clinically-relevant low concentrations (as low as 5 cells/mL) at an acceptable throughput (200 μL/min). The retrieval and successful propagation of captured prostate cancer cells is also investigated and discussed in this thesis.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Dr. Edward J. Park
Dr. Timothy V. Beischlag
Department: 
Applied Sciences: School of Mechatronic Systems Engineering
Thesis type: 
(Thesis) Ph.D.

A South African Developmental State? The Need to Overcome Incapacity and Pursue Embedded Autonomy in the 21st Century; - AND - On the Fringes: Housing Policy, Urban Slums, and the Necessity for a New Direction in South Africa

Author: 
Date created: 
2016-08-08
Abstract: 

1) In the years leading up to and immediately following the African National Congress’ landslide victory in the country’s first truly democratic elections, much anticipation and hope about South Africa’s future were held by all. However, despite its transition to democracy and departure from the institutionalized racism of apartheid in 1994, South Africa remains one of the most unequal societies in today’s global system. This essay explores the applicability of the developmental state framework given South Africa’s unique history and circumstances, considering arguments that assert South Africa can become a developmental state in spite of its deficiencies and arguments that argue against such assertions. This essay aligns with the former, arguing that while South Africa suffers extreme deficiencies that currently preclude it from becoming a 21st century developmental state, this does not mean that it can never become one. 2) The Universal Declaration of Human Rights (1948) enshrines the right to adequate housing, a concept that includes attributes such as security of tenure, protection from eviction, availability of services, and affordability. Since 1948, globalization and industrialization have ignited increasingly intense rural-to-urban migrations that strain cities’ abilities to house people. In South Africa, urban slums are prominent features of cities like Cape Town, Johannesburg, and Durban. Since 1994, the African National Congress has battled to deliver housing to the poorest of South African citizens, but evidence shows that its efforts, mandated by national housing policies, are failing. This essay investigates this failure by examining the neoliberal underpinnings of South Africa’s various housing policies and exploring the arguments of two camps in the literature – one that argues for greater inclusion of slum communities and one that argues for a more enabling policy environment. Through this exploration, the essay suggests that a combination of these two approaches presents the best suited housing strategy for South Africa moving forward.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Christopher Gibson
Department: 
Arts & Social Sciences: School for International Studies
Thesis type: 
(Extended Essays) M.A.

Surface Modification of Indium Tin Oxide

Author: 
Date created: 
2017-07-26
Abstract: 

Indium tin oxide serve a critical function in many organic devices, such as organic light emitting diodes and organic photovoltaics. To optimize the performances of these devices, it is desirable to tune the interface between the indium tin oxide and the next functional layer of these devices. A common surface modification of transparent conductive oxides is through the use of self-assembled monolayers. This methodology enables a simultaneously tuning of the properties and performance of this interface, including the surface energy, work function and durability of the transparent conductive oxide. Phosphonic acid and silane based monolayers have been extensively studied and used in devices for their ability to tune the interfacial properties of transparent conductive oxide. Herein, alcohol based monolayers are first demonstrated on transparent conductive oxide surfaces. The electrochemical and chemical stabilities of alcohol based monolayers, as well as changes in the optical properties of the Indium tin oxide as a function of their stability were evaluated in comparison to more traditional routes of surface modification, such as through the use of silanes and phosphonic acid based monolayers. The tunability of both work function and surface energy of the modified Indium tin oxide were also determined for assessing their electronic properties.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Byron Gates
Department: 
Science: Department of Chemistry
Thesis type: 
(Thesis) M.Sc.

Cold War Legacies in Contemporary Institutionalized Thinking on Development Communication: A Case Study of Two UNDP and EP ICT4D Reports

Author: 
Date created: 
2017-08-31
Abstract: 

Although information and communications technologies for development (ICT4D) is situated in a globalized Information Age nominally marked by a shift away from the dominant paradigm of development, Cold War-era ideological fallout continue to linger in development communication literature describing ICT4D. A critical hermeneutic analysis of two ICT4D reports, one commissioned by the European Parliament (EP) and one by the United Nations Development Programme (UNDP), delineates the Cold War legacies in contemporary supranational organizations’ institutionalized thinking on development communication.

Document type: 
Graduating extended essay / Research project
File(s): 
Senior supervisor: 
Yuezhi Zhao
Department: 
Communication, Art & Technology: School of Communication
Thesis type: 
(Extended Essay) M.A.

More than words: Using qualitative video-recall procedures to contextualize queer couples’ communication and partnered gay men’s sexual communication

Date created: 
2018-06-19
Abstract: 

This thesis contains two manuscripts related to the study of queer couples’ communication. In the first manuscript, I discuss qualitative video-recall procedures as valuable tools for generating contextualized and queer-affirmative understandings of queer couples’ communication. I argue that these procedures address limitations of dominant approaches to couples’ communication research, enabling researchers to attend to important social and political factors that shape how queer couples communicate. In the second manuscript, I use these innovative research procedures to explore partnered gay men’s sexual communication. In this study, three diverse gay male couples had video-recorded conversations about their sexual relationships, followed by separate video-recall interviews. Findings explore how gay male couples collaboratively navigate complex sociopolitical contexts by resisting, creatively modifying, and negotiating dominant sexual scripts. I explore how dominant sexual discourses and interpersonal power dynamics shape these dyadic processes.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Sharalyn Jordan
Department: 
Education: Faculty of Education
Thesis type: 
(Thesis) M.A.

The genus of generalized random and quasirandom graphs

Author: 
Date created: 
2018-06-12
Abstract: 

The genus of a graph $G$ is the minimum integer $h$ such that $G$ has an embedding in some surface (closed compact 2-manifold) $S_h$ of genus $h$. In this thesis, we will discuss the genus of generalized random and quasirandom graphs. First, by developing a general notion of random graphs, we determine the genus of generalized random graphs. Next, we approximate the genus of dense generalized quasirandom graphs. Based on analysis of minimum genus embeddings of quasirandom graphs, we provide an Efficient Polynomial-Time Approximation Scheme (EPTAS) for approximating the genus (and non-orientable genus) of dense graphs. More precisely, we provide an algorithm that for a given (dense) graph $G$ of order $n$ and given $\varepsilon>0$, returns an integer $g$ such that $G$ has an embedding into a surface of genus $g$, and this is $\varepsilon$-close to a minimum genus embedding in the sense that the minimum genus $\g(G)$ of $G$ satisfies: $\g(G)\le g\le (1+\varepsilon)\g(G)$. The running time of the algorithm is $O(f(\varepsilon) n^2)$, where $f(\cdot)$ is an explicit function. Next, we extend this algorithm to also output an embedding (rotation system) of genus $g$. This second algorithm is an Efficient Polynomial-time Randomized Approximation Scheme (EPRAS) and runs in time $O(f_1(\varepsilon)\,n^2)$. The last part of the thesis studies the genus of complete $3$-uniform hypergraphs, which is a special case of genus of random bipartite graphs, and also a natural generalization of Ringel--Youngs Theorem. Embeddings of a hypergraph $H$ are defined as the embeddings of its associated Levi graph $L_H$ with vertex set $V(H)\cup E(H)$, in which $v\in V(H)$ and $e\in E(H)$ are adjacent if and only if $v$ and $e$ are incident in $H$. The construction in the proof may be of independent interest as a design-type problem.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Bojan Mohar
Department: 
Science: Department of Mathematics
Thesis type: 
(Thesis) M.Sc.

Blinded by emotion? The influence of social-affective cues on the attentional blink in borderline personality disorder

Author: 
Date created: 
2018-07-05
Abstract: 

The primary objective of this study was to examine the influence of socio-emotional stimuli on the attentional blink (AB) in borderline personality disorder (BPD). Evidence suggests the importance of exploring attentional biases in BPD related to social signals. Major hypotheses were that 1) the experimental paradigm would elicit an AB across participants, and 2) individuals with high (versus low) BPD features would identify fewer targets following presentation of negative and neutral stimuli. Participants (N=140) recruited from university and community settings self-reported on BP features and related psychopathology, and then engaged in a modified AB task. Within this task, the first target (T1) at two lags (3 and 7) was alternately replaced by a face expressing three negative (anger, fear, sadness), one ambiguous (neutral), and one positive (happy) emotion, while the second (T2) was a letter embedded within a scrambled face. As expected, there was evidence for an AB across low- medium- and and high- BPD groups. Contrary to prediction, however, BPD features did not significantly affect task performance for any facial emotion. Findings are discussed in the context of study limitations and future directions for attentional bias research in BPD.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Alexander L. Chapman
Department: 
Arts & Social Sciences: Department of Psychology
Thesis type: 
(Thesis) M.A.

Building a contemplative classroom for students with anxiety

Author: 
Date created: 
2018-06-19
Abstract: 

This thesis addresses student anxiety in school. Many students feel a deep and chronic sense of anxiety, and this thesis thematizes this topic around the author’s experience as a primary school teacher. The author undertakes autobiographical reflections on her teaching experience and observations about students she teaches, studies the literature on student anxiety, and finally brings all of these into the conceptual framework of contemplative inquiry. The contemplative inquiry framework provides a lens through which to interpret and understand students who are anxious, and moreover, it provides ways of working with anxiety. The thesis presents the understanding that, for students to feel comfortable and safe in the classroom atmosphere, it is vital for educators to help create a classroom that students may feel is positive. The thesis goes into detail on inner work, mindfulness, and living curriculum. The author’s first-person experience of studying and learning in her Master of Education program, as well as autobiographical writing that capture the author’s childhood memories that pertain to the thesis topic, are presented in this thesis.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Heesoon Bai
Department: 
Education:
Thesis type: 
(Thesis) M.A.

Challenging knowledge divides: Communicating and co-creating expertise in integrated knowledge translation

Date created: 
2017-07-19
Abstract: 

To solve complex problems, it makes sense to seek diverse perspectives to develop research-based solutions. In the Canadian health sector, this collaborative approach to research is often called integrated knowledge translation (IKT). This thesis is concerned with how boundaries are both essential and obstructive in IKT. While the goal of partnering is to leverage different expertise, diversity also presents some of the most significant challenges to success, creating barriers that block communication and constrain knowledge sharing. Using situational analysis to explore interview and case study data, I explore how knowledge boundaries are experienced within IKT projects. I outline four discursive positions that emerge, and argue that recognizing their distinct characteristics is important for progress in IKT. I also compare and contrast concepts of boundary work and boundary objects as theoretical lenses for IKT analyses, and argue that broadening our conceptual toolbox is beneficial for the study and practice of IKT.

Document type: 
Thesis
File(s): 
Senior supervisor: 
Ellen Balka
Department: 
Communication, Art & Technology: School of Communication
Thesis type: 
(Thesis) M.A.

The use of submodels as a basis for efficient estimation of complex models

Author: 
Date created: 
2017-11-08
Abstract: 

In this thesis, we consider problems where the true underlying models are complex and obtaining the maximum likelihood estimator (MLE) of the true model is challenging or time-consuming. In our first paper, we investigate a general class of parameter-driven models for time series of counts. Depending on the distribution of the latent variables, these models can be highly complex. We consider a set of simple models within this class as a basis for estimating the regression coefficients in the more complex models. We also derive standard errors (SEs) for these new estimators. We conduct a comprehensive simulation study to evaluate the accuracy and efficiency of our estimators and their SEs. Our results show that, except in extreme cases, the maximizer of the Poisson generalized linear model (the simplest estimator in our context) is an efficient, consistent, and robust estimator with a well-behaved standard error. In our second paper, we work in the context of display advertising, where the goal is to estimate the probability of conversion (a pre-defined action such as making a purchase) after a user clicks on an ad. In addition to accuracy, in this context, the speed with which the estimate can be computed is critical. Again, computing the MLEs of the true model for the observed conversion statuses (which depends on the distribution of the delays in observing conversions) is challenging, in this case because of the huge size of the data set. We use a logistic regression model as a basis for estimation, and then adjust this estimate for its bias. We show that our estimation algorithm leads to accurate estimators and requires far less computation time than does the MLE of the true model. Our third paper also concerns the conversion probability estimation problem in display advertising. We consider a more complicated setting where users may visit an ad multiple times prior to taking the desired action (e.g., making a purchase). We extend the estimator that we developed in our second paper to incorporate information from such visits. We show that this new estimator, the DV-estimator (which accounts for the distributions of both the conversion delay times and the inter-visit times) is more accurate and leads to better confidence intervals than the estimator that accounts only for delay times (the D-estimator). In addition, the time required to compute the DV-estimate for a given data set is only moderately greater than that required to compute the D-estimate -- and is substantially less than that required to compute the MLE. In summary, in a variety of settings, we show that estimators based on simple, misspecified models can lead us to accurate, precise, and computationally efficient estimates of both the key model parameters and their standard deviations.

Document type: 
Thesis
Senior supervisor: 
Rachel Altman
Department: 
Science: Department of Statistics and Actuarial Science
Thesis type: 
(Thesis) Ph.D.