title: Experimenting with sex and speciation: Does intersexual co-evolution drive population divergence?

contributor:
Chippindale, Adam K.
Biology

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subject:
Biology
Intersexual co-evolution

abstract: Thesis (Master, Biology) -- Queen's University, 2008-08-13 12:29:52.602

abstract: It has been almost 150 years since Darwin’s “The Origin of Species” was published, yet the mechanisms that lead to the creation of new species are still a topic of fervent research in Evolutionary Biology. In the last several decades, there has been considerable interest in how genetic drift and adaptive processes internal to populations may lead to population divergence. It has been recognized that intersexual co-evolution may drive the rapid evolution of reproductive traits, leading to reproductive isolation between populations in allopatry. To explore the nature of this process, I conducted a series of interpopulation interaction experiments using a set of laboratory-evolved Drosophila melanogaster populations. These “B” (for baseline) populations share a common ancestor and had evolved in identical habitats in allopatry for 650-700 generations prior to my experiments. When different populations were combined in competitive fitness assays, I found that foreign males usually suffer depressed fitness when competing with males who share a common evolutionary history with the focal females. I selected a subset of B populations to investigate potential sources of variation that could explain this result. I examined; 1) characters involved in post-copulatory interactions between mates and 2) traits involved in mating behaviour. I found that sperm precedence patterns varied significantly depending on female population of origin and suggestive evidence that males between populations vary in ability to compete in sperm offence. Males also varied in mating behaviour between populations, however we found no evidence that divergence of these traits was correlated to that of traits involved in post-copulatory interactions, suggesting that understanding how intersexual co-evolution drives population divergence requires considering independent components of the reproductive phenotype and their contributions to overall fitness differences.

abstract: M.Sc.


title: The October Handshake of 1970: Making Sense of Canada's Recognition of the People's Republic of China

contributor:
Hill, Emily M.
History

rights: This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.

subject: Canada China

abstract: Thesis (Master, History) -- Queen's University, 2008-08-13 13:45:56.049

abstract:
After two decades of a disappointing relationship between Canada and the People's Republic of China (PRC)-- seriously damaged during the Korean War and relieved by wheat sales after the Great Leap-- Pierre Trudeau's government wanted to end China's isolation. The new prime minister was determined to ensure that his country could recognize the Communist regime. Even more surprisingly, Ottawa's opening of relations with Beijing would soon be followed by Washington. Such words as "rapprochement" were therefore repeated in North America as this extraordinary diplomatic event began to unfold in the late 1960s.
In hindsight, Sino-Canadian rapprochement seems full of contradictions: at a time when Canada's closest ally was still fighting in Vietnam, and when the Chinese were shouting anti-imperialist slogans during the Cultural Revolution, how could it be possible that Ottawa and Beijing wished to become friends? The central question this thesis poses and answers is why the two governments suddenly shifted positions at such a politically sensitive moment. Offering different ways to understand this thirty-year-old question, the thesis re-examines Trudeau's and Maoist China's remarkable, but often forgotten, diplomatic breakthrough. Indeed, although Canadians were paying closer attention to the nation's "October Crisis" in 1970, the "October Handshake" in Stockholm between representatives of Canada and China in the same month was also a significant event. The success of such a diplomatic achievement could be seen in the Sino-American rapprochement that followed and in China's new place in the world community. Drawing on various historical records, including materials from the archives of the Canadian Broadcasting Corporation and Queen's University, this study explains the agreement between Beijing and Ottawa in 1970 as the coincidence of three crucial conditions: the rapidly changing geopolitical circumstances at the time, a favourable internal political climate, and the matching mentality of the extraordinary players from both countries. Furthermore, while existing accounts of Sino-Canadian rapprochement highlight both countries' external relations, this thesis will argue that an exploration of the dynamics of domestic politics and the roles of individual leaders can expand our understanding of decision-making during the process of normalization of relations between China and Canada.

abstract: Preparation for publication.

abstract: M.A.


title: Glial Cell Line-Derived Neurotrophic Factor Modulates Structure and Function of Postnatal Myenteric Neurons

contributor:
Blennerhassett, Michael G.
Physiology

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subject: GDNF ENS

abstract: Thesis (Master, Physiology) -- Queen's University, 2008-09-03 13:27:23.042

abstract: The enteric nervous system (ENS) continues its development after birth, with formation of ganglia and functional synapses; plasticity is also demonstrated in significant axon growth that occurs after experimental colitis in the adult colon.  However, little is known about factors in the postnatal intestine that influence and regulate these processes.  Therefore we tested the effects of known neurotrophins, NGF, NT-3, BDNF and GDNF on neonatal rat myenteric neurons.  Cocultures were developed by isolating the myenteric plexus and surrounding muscular wall from neonatal rats, and effects of exogenous treatment of neurotrophins were analyzed using immunocytochemistry and image analysis.  Western blotting and immunocytochemistry were performed to detect implicated neurotrophins and their receptors in the postnatal intestine.  Functional aspects of effects of implicated neurotrophins were assessed by [3H]choline uptake and acetylcholine release in myenteric neurons.  Last, TNBS-colitis was induced in adult rats to determine changes in GDNF secretion during the course of the disease.  Application of 100ng/mL GDNF to a neonatal intestinal coculture containing neurons, glia and smooth muscle cells produced a 91.5% (p≤0.05) increase in axons.  GDNF induced morphological changes in the structure and organization of neurons and axons; the incidence of neurons present in ganglia increased by 11.2% (p≤0.05), with a 32.9% (p≤0.05) increase in aggregated axons.  Western blotting and immunocytochemistry confirmed intestinal smooth muscle as the major source of GDNF and demonstrated the presence of the GDNF receptor complex, GFRα1 and RET in the myenteric plexus.  Choline uptake significantly increased at 50, 100 and 150ng/ml doses of GDNF, whereas stimulated ACh release increased only at 100 and 150ng/ml doses.  In TNBS-colitis, a decrease in 35kD GDNF at days 1 and 6 post-induction of inflammation was observed, with a concomitant increase in 15kD GDNF.  We conclude that GDNF, produced by intestinal smooth muscle, is a key factor influencing development of the postnatal myenteric neuron and may play a role in ENS-restructuring post-inflammation.

abstract: M.Sc.


title: Novel robotic mechanisms for upper-limb rehabilitation and assessment

contributor:
Scott, Stephen H.
Hashtrudi-Zaad, Keyvan
Electrical and Computer Engineering

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subject:
Robot
Exoskeleton
Rehabilitation
Mechanical design

abstract: Thesis (Ph.D, Electrical & Computer Engineering) -- Queen's University, 2008-08-13 21:19:14.335

abstract:
Robotic rehabilitation and assessment of the human upper-limb following stroke is currently limited in part by the inability of robots to replicate natural motion.  In particular, motion of the shoulder girdle is usually neglected, despite the fact that the shoulder girdle is necessary to stabilize and orient the upper-limb during activities of daily living.  Without direct control of the shoulder girdle, it is not possible to monitor or prevent a patient from making compensatory movements, which inhibits functional recovery, nor is there a means to properly regain strength and coordination.  The more the robot is able to realistically mimic upper-limb motion, the more able the robot will be to assist with true functional movement training, which gives the patient the best chance of motor recovery.  To address this issue, a new adjustable robotic exoskeleton called MEDARM is proposed for rehabilitation and assessment of the shoulder complex.  MEDARM provides independent control of six degrees of freedom of the upper-limb: two at the sternoclavicular joint, three at the glenohumeral joint and one at the elbow.

A key design feature of the new robot is an innovative curved track mechanism actuated by a cable-drive transmission system.  To facilitate a performance evaluation of this new mechanism, a planar version of MEDARM was designed.  A full prototype of this planar robot was constructed and several fundamental metrics, including friction, inertia, and compliance, were used to test its mechanical performance.   Additionally, the functionality of the robot was examined using preliminary data recorded during a standard reaching task, and by implementing some basic rehabilitation algorithms.  This thesis describes the design of MEDARM and its planar counterpart in detail and the performance evaluation of the prototype is presented.

abstract: PhD


title: Insights into the solvation and selectivity of chiral stationary phases using molecular dynamics simulations and chemical force microscopy

contributor:
Cann, Natalie M.
Horton, J. Hugh
Chemistry

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subject:
Molecular dynamics
Chemical force microscopy
Chiral separations
Chiral stationary phases
Interface solvation
X-ray photoelectron spectroscopy

abstract: Thesis (Ph.D, Chemistry) -- Queen's University, 2008-08-14 11:26:37.436

abstract:
The mechanism by which chiral selectivity takes place is complicated by the surface morphology, the possible involvement of the solvent, and the characteristics of the chiral molecules at the surface. My goal is to model and understand the factors which lead to significant discrimination in the case of three closely related chiral stationary phases: N-(1-phenylethyl)-N’-[3-(triethoxysilyl)propyl]-urea (PEPU), [(3,5-dinitrobenzoyl)-amino]-N-[3-(triethoxysilyl)propyl]-2-phenylacetamide (DNB-phenyglycine), and [(3,5-dinitrobenzoyl)amino]-N-[3-(triethoxysilyl)propyl]-4-methylpentanamide (DNB-leucine).

   Ab initio calculations are used to develop molecular models of these chiral selectors. These models are employed in molecular dynamics (MD) simulations, which provide the theoretical framework for modelling chiral interfaces in different solvent mixtures. The MD simulations of PEPU interfaces show that, in alcohol/water mixtures, the alcohols form domains at the interface with the hydrophobic portions of the molecule tending to orient towards the surface.  This disrupts the water hydrogen bonding networks at the interface and leads to the exclusion of water from the surface region relative to the bulk. The MD simulations of DNB-phenylglycine and DNB-leucine selectors in hexane/2-propanol mixtures demonstrate that the interfaces are distinct both in terms of the selector orientations at the surface and in the number of hydrogen bonds formed with 2-propanol. This occurs despite the structural similarity between these two selectors.

   The interfaces are also prepared experimentally by attaching the chiral selectors onto oxidized Si(111) samples and AFM tips. In particular, for DNB-phenylglycine and DNB-leucine samples, two synthetic routes have been explored. Using AFM, the morphologies of the resulting chiral interfaces are obtained.  X-ray photoelectron spectroscopy and refraction-absorption infrared spectroscopy provide information regarding the relative distribution of the compounds on the surface. Using chemical force microscopy (CFM) measurements, chiral self-selectivity is examined in various solvent mixtures. For PEPU interfaces, the extent of hydrogen bonding at the surface is the dominant contributor to the measured forces. In the case of  DNB-phenylglycine and DNB-leucine, CFM measurements of the chiral self-selectivity in 2-propanol demonstrate that chiral discrimination is present in both systems, but larger forces are observed for DNB-phenylglycine, consistent with the molecular dynamics study that shows much weaker solvent interactions with this species.

abstract: PhD


title: Warriors of choice : the (Re)articulation of militarized masculinities in private and public special forces

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subject:
Special Forces
Private security firms
Joint Task Force 2 (JTF2)
Masculinity
Gender
Canadian Forces
Women

abstract: My thesis is an examination militarized masculinity in Canada's JTF2 Special Forces and the Private Security Firm Blackwater. I employ a gender analysis to highlight how militarized masculinity impedes women's participation from Special Forces and private security firms. Feminist scholarship by Cynthia Enloe, Ann Tickner, Sandra Whitworth, and Charlotte Hooper has examined how militarized masculinity is associated within a particular political/situational context and therefore should be understood in its plural--as militarized masculinities. However, there is limited scholarship focusing on how masculinities vary in Special Forces and private security firms. This lack of scholarship results in limited knowledge of the implications militarized masculinity in these units has for women's security and for women's participation in these units. The purpose of this thesis is to add to the current literature by exploring, through militarized masculinities, the gender barriers to women's participation and the consequences of the security produced when these units deploy. To analyze the impact of militarized masculinity in these units I conducted interviews with authorities on these units, applicants interested in participating in these units, and performed a content analysis of Blackwater's website. I argue based on the information gathered that militarized masculinity, while varied in its application in special units and private security firms, continues to impede women's participation and in some cases can cause greater insecurity for women where these units are deployed.

abstract: M.A.


title: A study of Chinese college English teachers in China - their beliefs and conceptual change.

contributor:
Luce-Kapler, Rebecca
Education

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subject:
Curriculum innovation
Teachers' beliefs
Conceptual conflict
Conceptual change
China
College English
Grammar-based approaches
Communicative approaches
Teacher-centered
Student-centered

abstract: Thesis (Ph.D, Education) -- Queen's University, 2008-08-17 09:08:34.638

abstract:
This research explored Chinese college English teachers’ beliefs and conceptual change in relation to the government-mandated shift from the traditional grammar-based approaches to language teaching to communicative language teaching (CLT).
This study employed an ethnographic approach and was conducted at a university in China. Six Chinese college English teachers agreed to participate in a three-month study during which their classroom teaching was observed and they were interviewed about their teaching experiences, understanding of the new teaching methods, and interpretations of the curriculum change. Three patterns of conceptual change were found in their beliefs about language teaching and learning: (a) change in teaching methods but no significant change in conceptions and beliefs, (b) change in both teaching methods and conceptions accompanied by painful conceptual conflict, and (c) change in both teaching methods and beliefs and an acquisition of broader curriculum perspectives. The stories and experiences of the participants indicate the complex, non-linear nature of conceptual development in their beliefs about language teaching. They struggled to expand their conceptual space by dwelling in the Zone of Between—between Chinese and Western educational traditions, between social, cognitive, and psychological processes of conceptual growth, between teaching and educating, and between curriculum-as-plan and curriculum-in-use.
This study is expected to have suggestions for ongoing college English teaching in China, provide insight for the research of teachers’ beliefs related to curriculum development in other cultural contexts, and inform language teacher education and development programs.

abstract: PhD


title: Mutation-based testing of buffer overflows, SQL injections, and format string bugs

contributor:
Zulkernine, Mohammad
Computing

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subject:
Vulnerability testing
Buffer overflow
SQL injection
Format string bug
Test adequacy

abstract: Thesis (Master, Computing) -- Queen's University, 2008-08-18 13:53:04.036

abstract:
Testing is an indispensable mechanism for assuring software quality. One of the key issues in testing is to obtain a test data set that is able to effectively test an implementation. An adequate test data set consists of test cases that can expose faults in a software implementation. Mutation-based testing can be employed to obtain adequate test data sets, and numerous mutation operators have been proposed to date to measure the adequacy of test data sets that reveal functional faults.  However, implementations that pass functionality tests are still vulnerable to malicious attacks. Despite the rigorous use of various existing testing techniques, many vulnerabilities are discovered after the deployment of software implementations, such as buffer overflows (BOF), SQL injections, and format string bugs (FSB). Successful exploitations of these vulnerabilities may result in severe consequences such as denial of services, application state corruptions, and information leakage. Many approaches have been proposed to detect these vulnerabilities. Unfortunately, very few approaches address the issue of testing implementations against vulnerabilities. Moreover, these approaches do not provide an indication whether a test data set is adequate for vulnerability testing or not.
   We believe that bringing the idea of traditional functional test adequacy to vulnerability testing can help address the issue of test adequacy. In this thesis, we apply the idea of mutation-based adequate testing to perform vulnerability testing of buffer overflows, SQL injections, and format string bugs. We propose mutation operators to force the generation of adequate test data sets for these vulnerabilities. The operators mutate source code to inject the vulnerabilities in the library function calls and unsafe implementation language elements. The mutants generated by the operators are killed by test cases that expose these vulnerabilities. We propose distinguishing or killing criteria for mutants that consider varying symptoms of exploitations. Three prototype tools are developed to automatically generate mutants and perform mutation analysis with input test cases and the effectiveness of the proposed operators is evaluated on several open source programs containing known vulnerabilities. The results indicate that the proposed operators are effective for testing the vulnerabilities, and the mutation-based vulnerability testing process ensures the quality of the applications against these vulnerabilities.

abstract: M.Sc.


title: In-line optical fiber interferometric refractive index sensors

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subject:
Refractive index sensoer
Single mode fiber
Abrupt taper
Connector-offset attenuator

abstract: Thesis (Master, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-08-18 15:42:59.506

abstract:
With many unique advantages compared to traditional sensors, optical fiber sensors have been studied and applied to many different areas. Interferometric sensors are one of the most useful sensor types due to their high sensitivities and relatively relaxed requirement on the stability of the optical source’s power level. In-line optical interferometric sensors received further attention as a result of compactness and robustness to the reference channel instability.
Long period gratings (LPG) are one of the most useful components in the in-line optical fiber sensors. However, the fabrication cost is normally high due to the expensive masks and stringent photolithographic procedures. Two new sensor components, namely abrupt tapers and connector-offset attenuators, are proposed as couplers in the optical fiber to couple light from core to cladding (or reverse) to replace LPGs. Using OPTIBPM software, the coupling coefficients between core and cladding modes are calculated. For an abrupt taper, coupling mostly happens between LP01 and LP0m modes; the first ten LP0m modes account for 98% of the incident mode energy. For a connector-offset attenuator, coupling mainly happens between LP01 and LP1m modes; the first ten LP0m and first ten LP1m modes account for 92% of the incident mode energy. The relative direction of two connector-offset attenuators is found to be very important to the interference performance. Phase dependent interference (attenuation range from 1 dB to 35 dB) is observed in the simulation for the interferometers using abrupt tapers and connector-offset attenuators.
Three interferometers are realized in the experiment using the abrupt tapers (Mach-Zehnder and Michelson) or the connector-offset attenuators (Michelson). Due to the interference between core and cladding modes, transmission is strongly dependent on wavelength ranging from 3 dB to 26 dB in the best implementation. Although it is difficult to make two perfect parallel connector-offset attenuators required by the Mach-Zehnder interferometers by using the fusion splicer, some evidence of constructive interference is observed in the experiment.
The interferometers are tested as refractive index (RI) sensors using the maximum attenuation wavelength shift relative to the RI change. Given that the minimum resolution of optical spectrum analyzer is 10 pm, ~10-4 difference of the RI can be detected by the interferometric sensors using the abrupt tapers or the connector-offset attenuators.

abstract: M.A.


title: Effectiveness of an on-body lifting aid at reducing low-back physical demands during an automotive assembly task : assessment of EMG response and user acceptability

contributor:
Stevenson, Joan M.
Kinesiology and Health Studies

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subject:
Ergonomic aid
Electromyography
Manual materials handling

abstract: Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2008-08-18 15:55:16.757

abstract: The purposes of the present work were: 1) to develop a computerized model that could predict the personal lift-assist device (PLAD) spring excursion and control spring stiffness for various individuals based on their anthropometry and working posture and 2) to test the PLAD’s (Version 6) effectiveness and user acceptability during static forward bending in an automotive assembly plant. Study 1 required 30 subjects to carry out a protocol that simulated unloaded stoop, squat, and freestyle lifting. Trunk inclination and knee angles were determined via 3 FastrakTM sensors, whereas a displacement transducer attached in-line with the PLAD determined excursion when the trunk or knees flexed. A model was created to determine spring excursion, and it was successfully validated with 10 additional subjects. A computerized model applying the excursion model and mathematical equations was also developed to calculate the required spring stiffness for offsetting a proportion of the L4/L5 bending moment for each individual in various postures. Study 2 investigated the effectiveness and user acceptability of the PLAD at an automotive manufacturing facility, using operators who performed an assembly process requiring forward bending and static holds. Surface EMG data were collected at six sites on the low back and abdomen, and a tri-axial accelerometer was mounted on each subject’s sternum to measure trunk inclination. A 20% reduction in the L4/L5 bending moment was provided to each wearer using the aforementioned computerized model. The PLAD was able to significantly reduce low back muscular activity, predicted-compression, and ratings of perceived exertion, without significantly changing abdominal activity or trunk inclination. Workers had positive opinions about the device, and 80% said they would wear the device everyday on-line. Additionally, the computerized model developed in Study 1 was effective, as worker low back muscular activity was reduced by approximately 20% when wearing the PLAD. With slight alterations, the PLAD appears to be beneficial in reducing low back forces and discomfort in many tasks that place excessive biomechanical loading on the low back.

abstract: M.Sc.


title: Social interaction and participation in activities for students with and without intellectual disabilities

contributor:
Minnes, Patricia
Psychology

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subject:
intellectual disabilities
participation in activities
social interaction

abstract: Thesis (Master, Psychology) -- Queen's University, 2008-09-18 14:51:50.134

abstract: Adolescence marks a time of increased social freedoms and opportunities to participate in new productive and leisure activities. As compared to typically developing high school students, those with intellectual disabilities (ID) can face more barriers to involvement in these activities. This study examined the involvement of high school students with and without ID in productive and leisure activities. Furthermore, it identified factors related to involvement, and it examined students’ satisfaction with their social interactions. Forty-seven typically developing high school students completed in-person interviews, and 45 of the students’ parents completed telephone interviews. Archival data from 63 parents of high school students with ID and 41 students with ID were also used. Students provided information about their satisfaction with social interactions, and, additionally, typically developing students provided information about the productive and leisure activities in which they participated. Parents in both groups provided information about their adolescents’ adaptive functioning and maladaptive behaviour, and parents of students with ID also provided information about the productive and leisure activities in which their adolescent participated. Results showed that typically developing students were more likely to be involved in employment and unstructured leisure activities than students with ID; however, there was no difference in involvement between the two groups for volunteer and structured leisure activities. Adaptive functioning was related to involvement in structured and unstructured leisure activities. Maladaptive behaviour was related to involvement in productive activities. Typically developing adolescents had a greater number of general daily interactions than adolescents with ID, and they were more satisfied with the quality of these interactions than students with ID. There was no difference in the quantity of close personal interactions between the two groups; however, typically developing students were more satisfied with the quality of their close personal interactions than students with ID. Implications and directions for future research are discussed.

abstract: M.Sc.


title: Defining the Role of the SHP2 Protein Tyrosine Phosphatase in FcepsilonRI Signaling in Mast Cells

contributor:
Craig, Andrew W.
Biochemistry

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subject:
Mast Cells
SHP2
FcepsilonRI
Cytokine Production

abstract: Thesis (Master, Biochemistry) -- Queen's University, 2008-08-20 13:51:18.751

abstract: Mast cells are granulocytes that are a key component of the innate and adaptive immune system, and contribute to allergic disorders. Mast cell activation following clustering of the high affinity IgE receptor (FcepsilonRI) by multivalent antigens requires reversible tyrosine phosphorylation of myriad signaling proteins. Activated mast cells rapidly release granule contents (eg. histamine and serine proteases) that cause vascular permeability, and in a more delayed manner they also synthesize and secrete eicosanoids and numerous cytokines (eg. IL-6 and TNFalpha) that recruit activated leukocytes. FcepsilonRI signaling is initiated by Lyn, a Src Family Kinase (SFK), that phosphorylates immunoreceptor tyrosine-based activation motifs (ITAMs) found on the FcepsilonRI beta and gamma chains. This allows recruitment of Fyn SFK and Syk kinase that bind ITAMs and phosphorylate numerous downstream targets. Src Homology 2 domain-containing Phosphatase 2 (SHP2, encoded by ptpn11/shp2) is known to be recruited to several phosphorylated proteins following FcepsilonRI aggregation in mast cells, however attempts to define the role of SHP2 have been hampered by its essential role during embryonic development and hematopoiesis in mice. Recently, conditional SHP2 knock-out mice (shp2fl/fl) have been created allowing for shp2 inactivation in a tissue-specific manner by Cre recombinase. Here we describe the use of transgenic mice expressing a modified estrogen receptor-Cre Recombinase (TgCreER*) on a shp2fl/fl genetic background, that allows for maturation of bone marrow-derived mast cells (BMMCs) prior to shp2-inactivation using 4-hydroxytamoxifen (4OH-TM). SHP2-depleted BMMCs display reduced phosphorylation of the FcepsilonRI beta chain, but exhibit extended phosphorylation of Syk kinase. Additionally, SHP2-deficient cells display a defect in the activation of both Erk mitogen-activated protein kinase and Akt, which correlates with an observed defect in the production of TNFalpha and Leukotriene C4.  Finally, we show that SHP2-deficient BMMCs display elevated FcepsilonRI-evoked phosphorylation of Csk-Binding Protein (Cbp or PAG) on residue Y317, which recruits C-terminal Src kinase (Csk) that phosphorylates SFKs on an inhibitory tyrosine. This hyperphosphorylation of Cbp correlates with elevated phosphorylation of the C-terminal inhibitory tyrosine on Fyn kinase. This study provides new insights into the role of SHP2 as a positive effector of FcepsilonRI signaling and cytokine production in mast cells.

abstract: Please restrict for 6 months - we wish to publish the work in the scientific literature prior to this being accessible to the public.

abstract: M.Sc.


title: Cultural Brokering : Art, National Identity, and the Influence of Free Trade

contributor:
Jessup, Lynda
Art History

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subject: Canada

subject: Mexico

subject: Free Trade

subject: North American Free Trade Agreement

subject: “Mexican Modern Art, 1900-1950”

subject: “Panoramas: The North American Landscape in Art”

subject: Cultural Brokering

subject: North American Integration

subject: Nationalism

subject: Neoliberal Globalization

subject: National Identity

subject: Cultural Diplomacy

abstract: Thesis (Master, Art History) -- Queen's University, 2008-08-20 15:05:45.256

abstract: This thesis explores the intersections of culture, nationalism, and neoliberal globalization through examination of the construction of Mexican identity in Canada after the implementation of the North American Free Trade Agreement (NAFTA) in 1994.  I evaluate how visual art has been used by the governments of Canada and Mexico to negotiate new bilateral relationships in the face of increased North American integration under free trade.  My study includes analysis of two Canada-based exhibitions, “Mexican Modern Art, 1900-1950” and “Panoramas: The North American Landscape in Art.”  Framing my discussion within the larger history of North American integration, I argue that these two exhibitions are part of a larger exchange in the area of cultural diplomacy between Canada and Mexico, which was especially prominent at the turn of the millennium.  These case studies provide a means to assess the manipulation of culture, the creation of a new North American identity, and the management of national/ist narratives within the larger project of neoliberal globalization.  Critically situating my study within the current discourse of globalization theory, I contend that artworks in these exhibitions were positioned in a manner to positively reinforce new trade relationships under NAFTA.

abstract: M.A.


title: Influence of polymorphisms in the thymidylate synthase gene on plasma homocysteine concentration

contributor:
King, Will D.
Massey, Thomas E.
Community Health and Epidemiology

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subject:
Thymidylate synthase
Polymorphism
Homocysteine

abstract: Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2008-08-21 16:05:02.797

abstract:
Background:  Significant interest in homocysteine exists due to its established role in embryogenesis, cardiovascular disease and neurotoxicity. This research investigates total plasma homocysteine in the context of carcinogenesis among healthy individuals aged 20 to 50 years. It is hypothesized that during this timeframe, elevated total plasma homocysteine (tHcy) concentration implicates a breakdown of the methionine-homocyteine biosynthesis pathway, in which folate deficiency, oxidative stress and altered DNA methylation capacity are potential consequences relevant to cancer etiology.
Purpose:  The overall purpose of this research is to identify novel genetic predispositions to a biomarker of cancer risk (tHcy). Interactions with dietary and genetic factors that act on this pathway are explored.
Methods:  The study population consisted of 284 healthy male and female volunteers recruited in Kingston, Ontario and Halifax, Nova Scotia between 2006 and 2008.  Specifically, polymorphisms under consideration included: i) the thymidylate synthase enhancer region (TSER) tandem repeat polymorphism and ii) the GC single nucleotide polymorphism (G/C SNP) both found on the 5’untranslated region (UTR) of the TS gene, and iii) the 6 base pair deletion at base pair 1494 (TS1494del6) found on the 3’UTR. TS polymorphisms were categorized based on either 5’ or 3’ location and were dichotomized to either high or low TS expression. Gene-gene interactions between polymorphisms in TS and methylenetetrahydrofolate reductase (MTHFR C677T) on tHcy concentration were also analyzed.  In addition, gene-diet interactions between serum folate and vitamin B12 status were examined.
Results:  Mean tHcy concentration for this study population was 8.65 µmol/L (standard deviation=1.96 µmol/L). After adjustment for confounders, higher mean tHcy levels of 0.48 μmol/L and 0.46 μmol/L were observed for the main effects of 5’polymorphisms (5’High) (p=0.04) and 3’polymorphism (3’High) (p=0.05), respectively.  The largest difference in mean tHcy concentration was observed for the joint effects of TS polymorphisms (µ=0.74 μmol/L, p=0.11).  Gene-gene interaction was observed between TS and MTHFR polymorphisms on tHcy concentrations (p<0.01).
Conclusions:  The findings of this research provide evidence of an association between TS polymorphisms and tHcy concentrations. These results suggest that TS polymorphisms, independent of dietary factors, may lead to elevated tHcy levels and potentially contribute to cancer development.

abstract: M.Sc.


title: Modeling cooperative gene regulation using Fast Orthogonal Search

contributor:
Korenberg, Michael J.
Electrical and Computer Engineering

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subject:
Gene regulation
Fast Orthogonal Search (FOS)

abstract: Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2008-08-21 10:30:24.293

abstract: A number of computational methods have suggested means by which gene transcription – the process through which RNA is created from DNA – is activated, but there are factors at work that no model has been able to fully explain. In eukaryotes, gene regulation is quite complex, so models have primarily focused on a relatively simple species, Saccharomyces cerevisiae (budding yeast). Because of the inherent complexity in higher species, and even in yeast, a method of identifying transcription factor (TF) binding motifs (specific, short DNA sequences) must be efficient and thorough in its analysis. This thesis shows that a method using the Fast Orthogonal Search (FOS) algorithm to uncover binding motifs as well as cooperatively binding groups of motifs can explain variations in gene expression profiles, which reflect the level at which DNA is transcribed into RNA for a number of genes. The algorithm is very fast, exploring a motif list and constructing a final model within seconds to a few minutes. It produces model terms that are consistent with known motifs, while also revealing new motifs and interactions, and it causes impressive reductions in variance with relatively few model terms over the cell-cycle.

abstract: M.Sc.


title: High Cell Density Culivation of Methylosinus Trichosporium OB3b

contributor:
Ramsay, Juliana A.
Ramsay, Bruce A.
Chemical Engineering

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subject:
Methylosinus Trichosporium
High Density Cell fermentation
Methanol
Methane Monooxygenase

abstract: Thesis (Master, Chemical Engineering) -- Queen's University, 2008-08-21 15:14:42.475

abstract:
Methylosinus trichosporium OB3b is a wild type, obligate methanotroph that grows only on one-carbon compounds and, in the absence of copper, produces high levels of soluble methane monooxygenase (sMMO) to metabolize methane to methanol.  SMMO has gained a great deal of attention in the bioremediation and chemical industries because of its low substrate specificity and its ability to oxidize chlorinated hydrocarbons. Much literature exists on cultivating this organism on methane, however no one has achieved dry cell weight densities exceeding 18 g/L. Biomass growth is limited due to mass transfer of methane to cells. This study investigated the growth of M. trichosporium on the water soluble carbon source, methanol while retaining sMMO activity.
Methanol was found to completely inhibit growth at 40 g/L. For online methanol measurements during fed-batch cultivation, an in situ probe was constructed from autoclavable materials and equipped with a Figaro TGS822 vapor sensor. The probe was designed to prevent the sensor coming in contact with water aerosols which affect its performance. The probe was an essential component of a feedback methanol control system. The cumulative CO2 production (CCP) strategy was used to feed methanol in fed-batch experiments.
In an initial bioreactor study, growth nutrients were fed in excess. The yields of biomass to nutrients were determined and the growth medium modified accordingly.  A biomass density of 19 g/L (growth rate of 0.013-0.065 h-1) was achieved with sMMO activity of 300 to 500 [µmol naphthol][g of biomass]-1[h]-1. The subsequent bioreactor study involved feeding of nutrients based on their yields in relation to methanol, a biomass density of 62 g/L (growth rate of 0.034- 0.08 h-1) was achieved.
The inoculum cultures utilized in the bioreactor studies were maintained on Noble agar plates containing nitrogen minimal salts medium and methane. After 6 months of subsequent plate transfers, M. trichosporium lost the ability to produce high levels of sMMO. The enzyme activity in methanol grown cells was recovered by subculturing in liquid NMS medium with methane as the sole carbon source, the activity increased from 8 to 600 [µmol naphthol][g of biomass]-1[h]-1. It is recommended that further studies be carried out on stimulating sMMO activity during cultivation on methanol.

abstract: M.Sc.


title: A comparison between solute transport in a discrete fracture and in a fracture network using a novel method for tracer detection

contributor:
Novakowski, Kent S.
Civil Engineering

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subject:
Civil engineering
Groundwater
Fractured rock

abstract: Thesis (Master, Civil Engineering) -- Queen's University, 2008-08-25 02:48:16.066

abstract:
Characterization of field-scale transport in bedrock aquifers is necessary due to the preponderance of groundwater contamination in these settings, and the increasing attention paid to these sites by regulatory bodies. However, as a result of the inherent complexity, and the consequent uncertainty in the dominant transport processes, large-scale transport in fractured rock is poorly understood.

In this study an investigation of large-scale transport was accomplished in part by conducting a radial-divergent tracer experiment in a 15 m thick section of aquifer with observations over a 245 m distance, using a novel tracer detection method capable of detecting breakthrough in individual fractures. The tracer experiment was conducted at a well-characterized field site in Smithville, Ontario, which is underlain by several large-scale bedding plane fractures, and used a submersible fluorometer to detect tracer arrival in-situ and to obtain vertical fluorescence profiles (VFPs) from observation boreholes.

To complete the investigation, hydraulic characterization data and VFPs were used to approximate the dominant transport pathways and a numerical model which solves for flow and transport in discrete fracture features (HydroGeoSphere) was used to simulate the tracer experiment. The results of the experiment and the modeling exercise were compared to those from a large-scale single fracture tracer experiment conducted previously at the same site, for which the modeling was revisited.

The experimental results of the fracture network experiment (FNE) were markedly more heterogeneous than those of the previously conducted single fracture experiment (SFE), with multiple peaks in the breakthrough curves, and scale dependent changes in breakthrough character. The VFPs illustrate that differences in the observed transport arise due to tortuous transport pathways within individual fracture features, and the combined effect of this tortuosity in the numerous fractures contributing to transport in the fracture network.

For the observation boreholes closest to the source (< 55 m), both the FNE and SFE models were capable of fitting the data using parameters within the range of values determined from prior lab and field experiments at the site. These fits became poorer over increased transport distances however, where the models used could not account for the increased effects of tortuosity.

abstract: M.Sc.


title: Canopy structural and meteorological influences on CO2 exchange for MODIS product validation in a boreal jack pine chronosequence

contributor:
Treitz, Paul
McCaughey, Harry
Geography

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subject:
Forest
CO2 flux
Lidar
MODIS
Forest structure

abstract: Thesis (Ph.D, Geography) -- Queen's University, 2008-08-22 08:50:51.44

abstract:
Previously disturbed and regenerating forests make up a significant proportion of the North American land area, and therefore play an important role in the exchanges of heat and trace gases between the terrestrial biosphere and the atmosphere. Assessment of local to global variability in CO2 exchanges by forests requires a combination of CO2 measurements made by eddy covariance (EC), field measurements, remote sensing data, and ecosystem models. The integration of these is problematic because of a mis-match in scale between measurement techniques. Despite the importance of regenerating forests on the global carbon balance, the processes affecting the carbon cycle within these forests is not well understood.

Airborne scanning light detection and ranging (lidar) instruments provide new opportunities to examine three-dimensional forest characteristics from the level of individual trees to ecosystems and beyond. Lidar is therefore an effective link between plot measurements, eddy covariance, and low resolution remote sensing pixels. This thesis dissertation presents new science on the use of airborne lidar for evaluating remote sensing products within heterogeneous and previously clearcut ecosystems. The goals of this thesis were to first understand the processes affecting CO2 exchanges within a previously disturbed boreal jack pine chronosequence located in Saskatchewan, Canada and then to apply this understanding to evaluate low resolution remote sensing data products from the Moderate Resolution Imaging Spectroradiometer (MODIS) using airborne lidar.

The first objective of this dissertation examined the factors that control light use efficiency (LUE) within the jack pine chronosequence during dry and wet years. The second objective examined the importance of vegetation structure and ground surface elevation on CO2 fluxes within a mature jack pine forest. The third objective developed and tested a simple model of lidar fractional cover and related this to the fraction of photosynthetically active radiation absorbed by the canopy (fPAR). This was then used to evaluate the MODIS fPAR product across the lower part of a watershed. Finally, the fourth objective was to model gross primary production (GPP) from airborne lidar. Lidar estimates of GPP were then compared with those from the EC system at the jack pine chronosequence and with the MODIS GPP (Collection 5) product.

abstract: PhD


title: Investigating benzene-initiated DNA double-strand breaks and recombination after acute and in utero exposure in mice

contributor:
Winn, Louise M.
Pharmacology and Toxicology

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subject:
Benzene
DNA double-strand breaks
In utero
Childhood leukemia
Developmental hematopoiesis

abstract: Thesis (Master, Pharmacology & Toxicology) -- Queen's University, 2008-08-22 11:07:49.162

abstract:
Benzene is an ubiquitous pollutant and industrial solvent that has been identified as a human leukemogen. Early exposure to environmental carcinogens such as benzene has been postulated to play a role in the etiology of childhood leukemia, however the association remains controversial. Genotoxic agents such as benzene can cause an increase in the frequency of DNA double-strand breaks, which may remain unrepaired or result in the initiation of DNA recombinational repair mechanisms.
The first objective was to investigate the induction of DNA double-strand breaks following in utero treatment to 200 mg/kg and 400 mg/kg benzene i.p. using the phosphorylated histone γ-H2A.X as a marker. Using immunoblotting, treatment with benzene did not increase the formation of γ-H2A.X in bone marrow cells of adult C57Bl/6N male mice and in maternal bone marrow, fetal liver, and post-natal bone marrow cells following in utero exposure to 200 mg/kg or 400 mg/kg benzene throughout gestational days 7 to 15.
Secondly, the study investigated the induction of micronuclei following in utero exposure to benzene. Acute exposure to 400 mg/kg benzene resulted in a statistically significant increase in the percentage of micronucleated cells in adult male bone marrow cells. In utero exposure to 400 mg/kg benzene throughout gestational days 7 to 15 also caused a statistically significant increase in the percentage of micronucleated cells in maternal bone marrow and post-natal bone marrow cells. Fetal liver cells also demonstrated a statistically significant increase in the percentage of micronucleated cells following 200 mg/kg and 400 mg/kg benzene.
The third objective was to investigate the initiation of DNA recombination following in utero exposure to benzene using the pKZ1 mutagenesis mouse model as a surrogate marker for non-homologous end joining activity. Adult pKZ1 mouse tissue yielded no recombination events; however, post-natal bone marrow cells did contain detectable recombination frequencies.
iii
In utero benzene exposure did cause an increasing trend in recombination events, and upon analysis of only the samples containing detectable levels of recombination, in utero exposure to 400 mg/kg of benzene caused a statistically significant increase in recombination frequency within this group.
These results demonstrate that benzene does not increase the formation of γ-H2A.X after acute and in utero exposure, however, the induction of micronuclei following acute and in utero benzene exposure confirmed that benzene is a genotoxic agent causing chromosomal breaks. In utero benzene exposure increased the frequency of DNA recombination in bone marrow from post-natal day 9 pups exhibiting detectable levels of recombination. Further investigations into different types of DNA damage and repair pathways are warranted to fully elucidate the role of genotoxic mechanisms in the etiology of benzene-induced childhood leukemias.

abstract: M.Sc.


title: Humanitarian engineering in the engineering curriculum

contributor:
Hall, Kevin
Civil Engineering

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subject:
Engineering education
Global engineering
Service learning
Humanitarian
Internationalization

abstract: Thesis (Ph.D, Civil Engineering) -- Queen's University, 2008-08-25 09:04:54.722

abstract:
There are many opportunities to use engineering skills to improve the conditions for mar-ginalized communities, but our current engineering education praxis does not instruct on how engineering can be a force for human development.  In a time of great inequality and exploitation, the desire to work with the impoverished is prevalent, and it has been proposed to adjust the engineering curriculum to include a larger focus on human needs.  This proposed curriculum philosophy is called humanitarian engineering.

Professional engineers have played an important role in the modern history of power, wealth, economic development, war, and industrialization; they have also contributed to infrastructure, sanitation, and energy sources necessary to meet human need.  Engineers are currently at an important point in time when they must look back on their history in order to be more clear about how to move forward.  The changing role of the engineer in history puts into context the call for a more balanced, community-centred engineering curriculum.

Qualitative, phenomenographic research was conducted in order to understand the need, opportunity, benefits, and limitations of a proposed humanitarian engineering curriculum.  The potential role of the engineer in marginalized communities and details regarding what a humanitarian engineering program could look like were also investigated.  Thirty-two semi-structured research interviews were conducted in Canada and Ghana in order to collect a pool of understanding before a phenomenographic analysis resulted in five distinct outcome spaces.

The data suggests that an effective curriculum design will include teaching technical skills in conjunction with instructing about issues of social justice, social location, cultural awareness, root causes of marginalization, a broader understanding of technology, and unlearning many elements about the role of the engineer and the dominant economic/political ideology.  Cross-cultural engineering development placements are a valuable pedagogical experience but risk benefiting the student disproportionately more than the receiving community.  Local development placements offer different rewards and liabilities.

To conclude, a major adjustment in engineering curriculum to address human development is appropriate and this new curriculum should include both local and international placements.  However, the great force of altruism must be directed towards creating meaningful and lasting change.

abstract: PhD


title: CO2 fixation : catalytic synthesis of β-hydroxycarboxylic acids

contributor:
Jessop, Philip G.
Chemistry

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subject:
Carbon dioxide fixation
Asymmetric catalysis
Carboxylation
Hydrogenation
Ketones

abstract: Thesis (Master, Chemistry) -- Queen's University, 2008-08-26 10:17:34.703

abstract:
Although carbon dioxide as a greenhouse gas is a serious environmental concern, it remains a valuable C1 source if viable methods are available for its conversion into useful products.  Herein, we present recent progress in the synthesis of aliphatic, aromatic, cyclic, and bicyclic beta-ketocarboxylic acids and the promising results from subsequent asymmetric hydrogenation to give beta-hydroxycarboxylic acids.

For the synthesis of the beta-ketocarboxylic acids, we investigated the effects of temperature, reaction time, and amount of 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU), which is a promoter for carbon-carbon bond formation with CO2.  The highest-yielding conditions for this DBU-promoted carboxylation reaction were used to carboxylate a number of aliphatic and aromatic substrates.

In order to determine whether the hydrogenation reaction will effectively compete with the in situ decarboxylation of the beta-ketocarboxylic acids, 1H NMR spectroscopy was used to monitor the rate of decarboxylation.  The solvent, electronic, and steric effect on the rate of decarboxylation was investigated by testing a variety of beta-ketocarboxylic acids.

Using RuCl2{(S)-BINAP} catalyst precursor, we determined the effect that solvent, H2 pressure, base, and substrate substitution had on the enantioselectivity of the asymmetric hydrogenation.  CH2Cl2 and MeOH were determined to be the best solvents because of the high hydrogenation selectivity, high enantioselectivity, and decreased reaction times.  These standard conditions were used to hydrogenate the variety of aliphatic and aromatic beta-ketocarboxylic acids previously synthesized.

Additional experiments, including deuterium labelling, were performed in an attempt to elucidate the hydrogenation mechanism and the actively hydrogenated tautomer.  These results lead us to believe that different reaction pathways occur in protic versus aprotic solvents.

The results discussed herein represent the first in depth investigation of transition metal catalyzed hydrogenation of beta-ketocarboxylic acids.  These results are very encouraging because enantioselectivities greater than 99 % were achieved for multiple beta-keto acids.  This synthesis is industrially advantageous due to the limited number of reactants required, their low-cost, and the potential for recycling unused materials.

abstract: M.Sc.


title: Vivid moments long remembered: the lifetime impact of elementary school musical theatre

contributor:
Upitis, Rena
Education

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subject:
Elementary school
Musical theatre
Long-term significance
Adults
Phenomenology
Arts
Curriculum
Memory
Qualitative
Descriptive statistics

abstract: Thesis (Master, Education) -- Queen's University, 2008-08-26 09:05:17.979

abstract: This phenomenological study examined the long-term significance of participation in elementary school musical theatre productions. The research aimed to explore the common and unique themes that emerged from adults recalling their childhood experiences, and how these experiences affected the development of musical and life-related skills. A questionnaire was used as the initial exploratory tool. It was distributed to a diverse group of 134 individuals, in retail, business and education settings, representing a stratified sample in two Ontario communities. Semi-structured interviews were conducted with six participants to elicit further memories of significant experiences related to their participation in elementary school musical theatre. The data analysis revealed five core themes and qualities related to the elementary school musical theatre experience including community and gender roles. The most significant meaning of school musical experiences for the participants had little to do with the skills developed in the arts, but rather focused on an increased sense of community and growth in self-awareness and confidence. Suggestions for future research on other salient aspects of elementary school are offered to shed further light on this phenomenon, which appears to have life-long and deep effects on those who are able to participate in elementary school musical theatre.

abstract: M.Ed.


title: Using Information Technology to Support the Discovery of Novel Knowledge in Organizations

contributor:
Chan, Yolande E.
Skillicorn, B. David
Management

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subject:
Novel Knowledge
Knowledge Discovery
Knowledge Management
Organizational Learning
Group Decision Support
Innovation
Creativity
Text mining
Web mining
Information Foraging
Design Science

abstract: Thesis (Ph.D, Management) -- Queen's University, 2008-08-26 09:25:31.367

abstract: In this dissertation, I examine how IT can support individuals, and in turn their organizations, in learning about and knowing their external environment on the Web.  Specifically, I examine novel-knowledge discovery in the context of the multi-level organizational learning process, focusing on cognitive developments and changes to mental models.  Novel knowledge is defined as knowledge that is potentially strategically important to the organization, not currently known to the organization, indirectly relevant and therefore difficult to find. Novel knowledge is proposed to be one of three different types of knowledge that organizations seek to discover in their environment. A theoretical framework is developed to identify the sets of tool characteristics, collectively referred to as levels, which are proposed to support the discovery of different types of knowledge, as well as different modes of learning and learning processes.  In addition, extensions to the 4I organizational learning process model are proposed, specific to searching and learning on the Web: 1) adding a fifth process – information foraging and search-term development, and 2) adding a fourth level to the learning process – the machine-level.  A competing theories approach is used to develop a rich understanding of knowledge discovery and learning on the Web.  Understanding which types of tools are useful in different learning contexts has implications for learning effectiveness and may help firms understand how to “manage” their learning. Tools for the discovery of highly novel knowledge are less prevalent than tools to support the other levels of knowledge discovery. Accordingly, a design theory for novel-knowledge discovery tools is proposed based on organizational learning theories.  An instantiation of the design theory, a novel-knowledge discovery tool, is developed and tested within the organizational learning process and compared to tools at the other two levels of knowledge discovery.  In addition, different processes involved in using a novel-knowledge discovery tool at the group level are examined.  Three separate studies were conducted, including a lab and field experiment, and case study. The results are proposed to demonstrate how novel-knowledge discovery tools can support organizational learning.

abstract: PhD


title: An Investigation into the Pathophysiology of Non-Specific Arm Pain: an Examination of the Utility and Reliability of Quantitative Electomyography

contributor:
McLean, Linda
Rehabilitation Science

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subject: non-specific arm pain

abstract: Thesis (Ph.D, Rehabilitation Science) -- Queen's University, 2008-08-27 14:53:55.892

abstract:
The wrist extensor muscles have been implicated in a work-related upper limb disorder referred to as non-specific arm pain (NSAP), which has an unknown pathophysiology.  The primary objective of this thesis was to perform an electrophysiological evaluation of NSAP to gain a better understanding of the underlying pathophysiology. Secondary objectives were to determine the utility and reliability of the decomposition-based quantitative electromyography (DQEMG) system used to examine NSAP.
	The utility of the DQEMG system was first tested to determine whether physiological changes in muscles of healthy individuals performing low-level fatiguing contractions could be detected using this approach.  Next, the reliability of the outcome variables produced through this system was tested on healthy individuals performing low-level non-fatiguing contractions.  A case-control study was then performed using DQEMG to determine whether there were measurable changes in electrophysiological variables that suggest whether NSAP is myopathic or neuropathic in nature.  Finally, the case control study was repeated using a less invasive approach of electrophysiological evaluation to determine if this method might be equally useful in determining the pathophysiology of NSAP.
Results revealed DQEMG can be effectively and reliably used to detect changes in the physiological characteristics of motor units that accompany fatigue. Specifically, decreases in mean motor unit firing rates along with increases in amplitude, duration, and area parameters of needle- and surface-detected motor unit potentials (MUPs) suggest that recruitment is a main cause of increased electromyographic amplitude parameters with fatigue.  Results of the reliability study suggested that DQEMG provides sufficiently consistent results to allow it to be effectively used for quantitative electromyographic (QEMG) analysis. In the first case control study, the QEMG parameters suggested that the underlying pathophysiology in NSAP may be myopathic in nature; specifically, QEMG findings for the NSAP group revealed smaller MUPs compared to the other groups. Lastly, the case control study using spike shape analysis across different levels of isometric wrist extension contractions was deemed to be useful in determining differences among the groups. This research suggests that NSAP may be myopathic in nature, since the NSAP group showed significantly lower mean spike amplitude and mean spike slope values compared to healthy subjects.

abstract: Please restrict for up to 1 year so we can insure that all manuscripts have been published in journals.

abstract: PhD


title: Regulation of cation channel voltage- and Ca2+-dependence in Aplysia bag cell neurons

contributor:
Magoski, Neil S.
Physiology

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subject:
Neuronal excitability
Ion channel regulation

abstract: Thesis (Master, Physiology) -- Queen's University, 2008-08-26 13:20:16.528

abstract:
Ion channel regulation is key to the control of excitability and behaviour.  In the bag cell neurons of Aplysia californica, a voltage- and Ca2+-dependent nonselective cation channel drives a ~30-minute afterdischarge, culminating in the release of egg-laying hormone.  Using excised, inside-out single channel patch-clamp, this study tested the hypothesis that inositol 1,4,5-trisphosphate (IP3), which is produced during the afterdischarge, and channel-associated protein kinase C (PKC), which is activated throughout the afterdischarge, cause a left-shift (enhancement) in both the voltage- and Ca2+-dependence of the cation channel.
Kinetic analysis of bag cell neuron cation channel voltage-dependence revealed that, with depolarization, the channel remained open longer and reopened more often.  A cation channel subconductance was also observed, and found to be 13 pS vs. the typical 23 pS full-conductance.  The cytoplasmic face of cation channel-containing patches was exposed to 1 mM ATP, as a phosphate source for channel-associated PKC, and/or 5 uM IP3.  Apparent PKC-dependent phosphorylation left-shifted voltage-dependence by -3 mV, although this effect was more prominent at negative voltages (between -90 and
-30 mV).  Conversely, IP3 right-shifted voltage-dependence (change in V1/2 of 6 mV).  Cation channel Ca2+-dependence was similar to that previously reported, with a control EC50 of 3-5 uM.  This was right-shifted by PKC (EC50 = 30 uM) and even more so by IP3 (apparent EC50 = 20 M).  PKC largely rescued the Ca2+ responsiveness in the presence of IP3 (EC50 = 20 uM).  Unexpectedly, IP3 plus ATP resulted in an increase in channel unitary conductance at more positive voltages.
The multi-faceted regulation of the bag cell neuron cation channel suggests sophisticated modulatory control.  Upregulation, such as depolarization and the left-shift in voltage-dependence with PKC, would drive the afterdischarge, while counteracting effects, such as IP3 right-shifting voltage-dependence, as well as PKC and IP3 suppressing Ca2+-dependence, would simultaneously or subsequently attenuate the channel, thus preventing an interminable afterdischarge.

abstract: M.Sc.


title: Motor imagery: does strategy matter?

contributor:
Brouwer, Brenda
Rehabilitation Science

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subject: Motor imagery

abstract: Thesis (Master, Rehabilitation Science) -- Queen's University, 2008-08-26 15:58:21.277

abstract: Motor imagery requires individuals to form an internal representation of a specific action within working memory without any overt output. Motor imagery has proven effective in improving motor performance of specific skills. This study explored whether different motor imagery strategies influence corticospinal excitability in young (20-35 years) and older subjects (over 55 years).  In addition, the effectiveness of these strategies in targeting modulations in motor cortical output and whether the hand “performing” the task was important were also examined. Motor imagery ability was measured using the Kinesthetic and Visual Imagery Questionnaire (KVIQ) and mental chronometry. Working memory including visuospatial, verbal and kinesthetic domains was measured by immediate serial recall. To determine the effect of imagery on corticospinal excitability transcranial magnetic stimulation (TMS) was applied over the contralateral motor cortex as subjects imagined abducting their index finger. Motor evoked potentials (MEPs) were recorded from first dorsal interosseous (FDI), abductor pollicis brevis and abductor digiti minimi muscles (ADM). As subjects performed motor imagery, they were guided by visual, auditory or a combination of visual and auditory cues. Strategies were introduced in randomized sequence interspersed with a rest and a muscle activation condition. Motor imagery ability and verbal working memory were comparable between young and older subjects (p > 0.05). In both groups, MEP amplitudes in the FDI muscle were significantly increased during motor imagery compared to rest regardless of the strategy used (p < 0.001). Visual cueing was the most effective at isolating facilitation to the target muscle (FDI), whereas with the auditory and combined strategies both FDI and ADM muscles generated MEPs that were comparable in amplitude (p > 0.05). TMS induced MEPs were greater in amplitude when the left hemisphere was stimulated during motor imagery of the right finger while being guided by either auditory or visual cueing. In combination, these findings suggest that motor imagery increases corticospinal excitability and the strategy used may serve to target the facilitation.

abstract: M.Sc.


title: Considering childlessness:  an argument for the extrication of childbearing and motherhood from the concept of womanhood

contributor:
Overall, Christine
Philosophy

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subject: Childlessness Womanhood

abstract: Thesis (Master, Philosophy) -- Queen's University, 2008-08-27 00:43:24.991

abstract:
The stereotypical concept of womanhood is tethered to childbearing and motherhood.  Even though childlessness is becoming more common, the belief seems to be that all women must want and should have children as well as should assume the role of primary caregiver.
	I explore and argue against the belief that bearing and raising children is essential to the concept of womanhood.  I pinpoint four reasons why childbearing and motherhood are thought to be rightly tethered to the concept of womanhood:  that childbearing and mothering are the “norm” for women, that women’s potential to bear life is considered a sufficient and necessary condition to reproduce, that the presence of a “maternal instinct” means women want to bear children and they exhibit maternal behaviour, and that it is “natural” for women to want to procreate and mother.
	I then present a series of arguments showing why childbearing and mothering must be extricated from the concept of womanhood.   I focus on the concern that the concept of womanhood demanding procreation means a woman cannot independently meet the criteria for womanhood, the oversimplifying consequences of making a biological possibility a defining characteristic of women, the oppressiveness of prescribing the demanding role of motherhood to all women, and the freedom associated with the child-free life.  I argue against the existence of the maternal instinct and point to the coercive manner in which the term “natural” is employed.  After illustrating the social pressures women face to procreate and mother, I argue that such pressure would not be needed if procreation and mothering were indeed “natural” for women.  Allowing for the possible existence of the “maternal instinct” I argue that its existence is irrelevant in light of the wax and wane of the importance placed on what is “natural” and the ability of social pressures to overcome what is deemed “instinctual” and “natural”.  Finally, I argue that both a belief in the “maternal instinct” and the idea that wanting and raising children is “natural” undermine belief in women’s intelligence.

abstract: M.A.


title: Alternative takes on information systems post-adoption behaviors : the deliberative, the ecological, and the emotional

contributor:
Webster, Jane
Management

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subject:
Post-adoption behaviors
Emotion
Information Systems
Information technology use
Performance
Cognition
Theory
Process
Variance
Events

abstract: Thesis (Ph.D, Management) -- Queen's University, 2008-08-27 09:00:57.168

abstract:
This thesis concerns individuals’ behaviors with Information Systems (IS) once an application has been applied by users in accomplishing their work activity. Despite research on IS acceptance and continuance, little is known about individuals’ cognitive, affective, and behavioral processes and their associated outcomes after the initial adoption of a system. My research aims to address this shortcoming. In doing so, this dissertation combines novel theories – the ecological perspective based on ecological psychology and the emotional perspective based on neuroscience, physiological, and psychological research – with the current IS post-adoption literature – the deliberative perspective – to the study of IS use as an ongoing behavioral process that unfolds over time.

Two studies were conducted to investigate these processes and outcomes. The first study used an experience sampling method. Employees of different organizations who used IS for their work were asked to carry a booklet and a pager for two weeks. Every time they were paged, they were asked to fill out both open-ended and close-ended questions about their feelings, thoughts and performance at the moment in the booklet. The second study followed an experimental design in order to investigate the phenomena of interest in a more controlled environment. The experiment combined multiple sources of data: such as protocol analysis, heart rate data, and analysis of behaviors through video coding. The overall results from both studies suggest that users do not think about the IS nor experience feelings related to the IS unless they are facing a difficulty with it (e.g., an error). Furthermore, the results indicate affective and physiological changes following difficulties with an IS as well as changes in cognitive and behavioral processes. Finally, the results show a relation between these affective processes and self-reported performance, and a relation between some of the cognitive and behavioral processes and both objective and self-reported performance.

Overall, this thesis provides a refreshing theoretical and empirical examination of the various events, processes and associated outcomes involved during actual IS use. The two empirical studies provide support for the theory of post-adoption IS use developed in this thesis. Finally, this thesis suggests exciting opportunities for future research.

abstract: PhD


title: Preparation and morphological study of composite nano-particles made of homopolymers

contributor:
Liu, Guojun
Chemistry

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subject: Composite polymer particles

abstract: Thesis (Master, Chemistry) -- Queen's University, 2008-08-27 12:16:37.142

abstract:
Composite polymer particles were made of two or more polymers. If these polymers are incompatible, the particles after polymer phase segregation exhibit complex morphologies which determine their properties and applications. Such particles may have applications in both academia and industry.

In this work, polystyrene (PS)/ poly(2-cinnamoyloxyethyl methacrylate) (PCEMA) and poly(acetyloxyethyl methacrylate) (PAEMA)/PCEMA composite polymer particles are prepared by the evaporation of toluene from PS/PCEMA/toluene and PAEMA/PCEMA/toluene droplets dispersed in an aqueous solution containing surfactants. The surfactants used for the two systems are poly(glyceryl methacrylate)100-block-poly(2-cinnamoyloxyethyl methacrylate)15 (PGMA100-b-PCEMA15) and poly(glyceryl methacrylate)300-block-poly(2-cinnamoyloxyethyl methacrylate-ran-acetyloxyethyl methacrylate)37 (PGMA300-b-P(CEMA-ran-AEMA)37), respectively, for the PS/PCEMA and the PAEMA/PCEMA systems. The morphologies of the PS/PCEMA and PAEMA/PCEMA composite particles are analyzed by transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS). The results indicate that the particles are polydisperse and of nanometer size. For the PAEMA/PCEMA particles, the preferred morphology is hemisphere, while for the PS/PCEMA system the morphology is a mixture of acorn and occluded core-shell. Based on Gibbs free energy theory, and knowing the corresponding surface tensions and interfacial tensions, the thermodynamic equilibrium morphologies for both kinds of composite particles were found. Due to the uncertainty during measurements and calculations, and the influence of kinetic factors, the theoretical predictions agreed only partially with the experimental observations.

abstract: M.Sc.


title: Scheduling in IEEE 802.11e networks with quality of service assurance

contributor:
Hassanein, Hossam S.
Electrical and Computer Engineering

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subject:
Scheduling
HCCA
SFS
IEEE 802.11e

abstract: Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2008-08-27 14:20:34.806

abstract: Wireless Local Area Networks (WLANs) have gained popularity at an unprecedented rate, at home, at work and in public hot spot locations. In this thesis, a Selectivity Function Scheduler (SFS) is proposed for IEEE 802.11e WLANs. The SFS aims at providing Quality of Service (QoS) assurance for different traffic types such as delay bound and throughput while maintaining fairness among flows and accommodating fluctuations of real-time applications. The SFS defines several functionalities that accurately analyze and compute the number of data frames at each traffic stream’s transmission queue, and allocate adaptive transmission opportunities (TXOPs) to traffic streams based on online observed physical rate instead of minimum physical rate. Moreover, the SFS incorporates a selectivity function (SF) that differentiates between traffic streams and assigns polling priorities accordingly. SFS appropriately calculates variable service interval lengths depending on actual traffic conditions. The SFS scheme is evaluated under different mixes of traffic and for various characteristics of the IEEE 802.11e and compared with the performance of the standard scheduler. Simulation results indicate that the SFS scheme achieves better system performance in terms of high throughput and low packet drop ratio, succeeds in providing QoS assurance for both constant bit rate (CBR) and variable bit rate (VBR) traffic. The SFS scheme also shows higher fairness among users of a same class, as well as between different classes.

abstract: M.Sc.


title: Translating messages from curriculum statements into classroom practice: communication in Grade 9 Applied mathematics

contributor:
Roulet, Geoffrey
Education

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subject:
Mathematics education
Mathematics curriculum
Communication in mathematics

abstract: Thesis (Master, Education) -- Queen's University, 2008-08-27 16:18:13.815

abstract: This qualitative case study describes how two teachers translate communication messages from curriculum statements into classroom practice. These illuminative cases illustrate the perspectives and practices of two teachers who support the spirit of the Ontario Mathematics Curriculum by working to implement communication in the Foundations of Mathematics (MFM1P), Grade 9, Applied course (Ontario Ministry of Education, 2005). Data for this study were collected from individual interviews with teachers, classroom observations, and document analysis. Grade 9 Applied mathematics teachers across Ontario indicate on surveys that they support communication in the mathematics classroom (Education Quality and Accountability Office, 2007; Suurtamm & Graves, in press). Despite evidence of support for this aspect of the curriculum, findings from this study point to a need for finer analysis of teachers’ perspectives and practices when it comes to communication in mathematics. The cases presented in this thesis illustrate different images, or meanings, associated with communication in mathematics. Furthermore, even in unique cases where the gap between curriculum developers and teachers images is minimal, the idealized vision of communication may not be realized in classroom practice since teachers may face challenges in implementation. The teachers report that despite additional challenges involved with implementing communication in Grade 9 Applied mathematics, teaching in this context can be a rewarding experience. To minimize the gap between images of communication that are translated from curriculum statements into classroom practice, findings from this study indicate that curriculum developers must find ways to help teachers understand the rationale behind curriculum initiatives. Future research might explore ways to help familiarize teachers with the theory and research underlying communication in mathematics. Research might also examine the impact that these initiatives have on teachers’ perspectives and practices.

abstract: M.Ed.


title: Chatting, befriending, and bullying: Adolescent Internet Experiences and Associated Psychosocial Outcomes

contributor:
Craig, Wendy M.
Psychology

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subject: Internet Adolescent relationships cyberbullying

abstract: Thesis (Ph.D, Psychology) -- Queen's University, 2008-08-27 21:52:03.178

abstract:
Over the past 10 years, internet use has become an integral part of adolescent
socialization. Teenagers use the internet to communicate with known others as well as with
strangers. They engage in online entertainment in the form of gaming and surfing the web.
While adolescents mainly use the internet to maintain pre-existing friendships, some
adolescents make close friendships online. They also encounter negativity online in the
form of cyberbullying. Despite the pervasiveness of internet use, relatively little is known
about long-term effects of internet activities on adolescent psycho-social adjustment. This
group of studies aimed to identify change over time associated with various aspects of
internet use. First, the long-term associations between different internet-based activities
and adolescent social relationships were identified. Second, the differences between
adolescents who form close internet-based friendships and those who do not were
examined. Finally, the importance of internet-based bullying was identified. Overall,
results suggest that while some internet-based activities are associated with increased
positive effects, some internet activities are also associated with negative outcomes over
the long term. Having close online friends as part of one’s peer group is associated with
negative psychosocial factors. Cyberbullying was identified as a form of bullying that is
associated with many important outcomes. The implications of these findings call for an
increase in monitoring, involving not only supervision but direct communication, of
adolescents’ internet activities, and increased communication in families about internet use.

abstract: PhD


title: Estimating the burden of occupational bladder cancer in Ontario using the CAREX Canada database

contributor:
Aronson, Kristan J.
Marrett, Loraine
Community Health and Epidemiology

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subject:
occupational bladder cancer
population attributable risk
occupational exposure

abstract: Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2008-08-29 20:08:46.713

abstract:
Objective: This study attempts to estimate the proportion of incident cases of bladder cancer in Ontario, Canada that is due to exposure to occupational carcinogens.
Methods: The population attributable risk approach is used to estimate the proportion of bladder cancer in Ontario that is due to occupation.  Risk ratios were obtained from a review of epidemiologic literature using a priori inclusion and exclusion criteria.  Summary risk estimates for each bladder carcinogen included were calculated using RevMan 4.2.  The CAREX Canada database provided Ontario-specific estimates of the proportion of workers exposed to bladder carcinogens.
Results: In Ontario, the proportion of bladder cancer due to occupational exposure is approximately 5.6% (95% CI 0.2% to 14%).  Based on the incident number of bladder cancer cases in 2001 in Ontario, it is estimated that approximately 52 new cases of bladder cancer were due to occupational exposure to polycyclic aromatic hydrocarbons (PAHs), diesel exhaust, aromatic amines and 2-naphthylamine.  An alternate interpretation is if these occupational exposures were eliminated, 52 cases of bladder cancer per year in Ontario alone could be avoided.
Conclusion and Recommendations: The current study advances our knowledge of the extent to which specific occupational bladder carcinogens contribute to the overall bladder cancer burden in Ontario.  The current study highlights the utility of the CAREX Canada database in advancing current knowledge on the burden of occupational cancer in Ontario.  The methods used to estimate the proportion of bladder cancer attributable to occupational exposure in Ontario may be replicated to estimate the proportion of cancer in Ontario that is due to occupational exposure.

abstract: M.Sc.


title: Separating Invariants

contributor:
Wehlau, David
Mathematics and Statistics

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subject: Invariant Theory

abstract: Thesis (Ph.D, Mathematics & Statistics) -- Queen's University, 2008-08-28 14:14:04.138

abstract: Roughly speaking, a separating algebra is a subalgebra of the ring of invariants whose elements distinguish between any two orbits that can be distinguished using invariants.  In this thesis, we introduce the notion of a geometric separating algebra, a more geometric notion of a separating algebra. We find two geometric formulations for the notion of separating algebra which allow us to prove, for geometric separating algebras, the results found in the literature for separating algebras, generally removing the hypothesis that the base field be algebraically closed. Using results from algebraic geometry allows us to prove that, for finite groups, when a polynomial separating algebra exists, the group is generated by reflections, and when a complete intersection separating algebra exists, the group is generated by bireflections.  We also consider geometric separating algebras having a small number of generators, giving an upper bound on the number of generators required for a geometric separating algebra. We end with a discussion of two methods for obtaining new separating sets from old. Interesting, and relevant examples are presented throughout the text. Some of these examples provide answers to questions which previously appeared in print.

abstract: PhD


title: Saccadic eye movements and executive function in children with Fetal Alcohol Spectrum Disorders (FASD): Results from a multi-centered study

contributor:
Reynolds, James
Neuroscience Studies

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subject:
Fetal Alcohol Spectrum Disorders
Saccades

abstract: Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2008-08-28 15:41:20.595

abstract: A serious consequence of maternal consumption of alcohol during pregnancy is the fetal alcohol syndrome (FAS): characterized by growth deficiency (both pre- and post-natal), craniofacial dysmorphology and central nervous system (CNS) dysfunction.  However, in the absence of the characteristic facial features, and without confirmed history of alcohol exposure, clinical diagnosis remains a significant challenge.  Recently, the term fetal alcohol spectrum disorders (FASD) has been adopted to encompass all diagnoses relating to a history of prenatal alcohol exposure.  The purpose of this study was to test the following three general hypotheses: Children with FASD 1) demonstrate specific deficits in oculomotor control that can be measured using saccadic eye movement tasks, 2) display specific deficiencies in multiple domains of executive function that can be determined using standardized neuropsychological tasks, and 3) reveal deficits in oculomotor control that correlate with deficiencies in executive function as measured using standardized neuropsychological tasks.  A preliminary study revealed significant deficits in saccadic eye movement tasks and provided the foundation for a large, multi-centered study assessing oculomotor control and neuropsychological function in children with FASD.  A mobile laboratory was created, which facilitated recruitment of 92 control subjects and 89 subjects with FASD.  We found significant evidence for oculomotor deficits across multiple outcome measures following the saccadic eye movement experiments, especially for oculomotor tasks that probe aspects of executive function.  Additionally, children with FASD exhibited performance deficits in neuropsychological tasks that assess planning, attention, spatial working memory and strategy; cognitive skills also included within the domain of executive function.  Finally, significant correlations between these two objective measures were found for children with FASD, which were not evident in the control sample.  These findings are consistent with significant frontal lobe dysfunction.  This is an exciting area of research that may hold promise in developing effective screening tools that can assist in the diagnosis of individuals with a history of prenatal alcohol exposure.

abstract: PhD


title: Chemical and Mechanical Adaptations of the Respiratory System at Rest and During Exercise in Healthy Human Pregnancy: Implications for Respiratory Sensation

contributor:
O'Donnell, E. Denis
Kinesiology and Health Studies

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subject:
Pregnancy
Exercise
Breathlessness
Control of Breathing
Acid-Base Balance
Female Sex Steroid Hormones
Respiratory Mechanics
Ventilation

abstract: Thesis (Ph.D, Kinesiology & Health Studies) -- Queen's University, 2008-08-28 16:01:40.78

abstract:
Human pregnancy is characterized by significant increases in central ventilatory drive and perceived respiratory discomfort (breathlessness).  The physiological mechanisms of hyperventilation and breathlessness in pregnancy remain largely unknown and understudied.
Objective:  The main purpose of this research was to elucidate the mechanisms of maternal hyperventilation, and to systematically examine the contribution of alterations in central ventilatory drive, static/dynamic respiratory mechanics and their interaction with respect to the intensity of perceived breathlessness during exercise in pregnancy.
General Methods:  Experiments were conducted between 34-38 wks gestation and again 4-5 months post-partum in a total of 35 healthy, young women.  A comprehensive mathematical model of ventilatory control was used to examine the role of alterations in wakefulness and central chemoreflex drives to breathe, acid-base balance and female sex hormones in maternal hyperventilation.  The effects of pregnancy on detailed ventilatory (breathing pattern, airway function, operating lung volumes, esophageal pressure-derived indices of respiratory mechanics) and perceptual (breathing and leg discomfort) responses to incremental cycle exercise to the limits of tolerance were also examined.
Results:  Maternal hyperventilation resulted from a complex interaction between alterations in arterial and central acid-base balance and other factors that directly affect ventilation, including increased wakefulness and central chemoreflex drives to breathe, increased metabolism and decreased cerebral blood flow.  Mechanical adaptations of the respiratory system, including recruitment of resting inspiratory capacity and reduced airway resistance, accommodated the increased demand for tidal volume expansion during exercise in pregnancy, while preserving effort-displacement and breathlessness-ventilation relationships.  Variation in the severity of gestational breathlessness could not be explained by respiratory mechanical/muscular factors, but ultimately reflected variation in the amplitude of maternal hyperventilation and temporal desensitization to the sensory consequences of increased ventilation.
Conclusion:  Our results indicated that 1) the hyperventilation and attendant hypocapnia/alkalosis of pregnancy can be explained by alterations in wakefulness and central chemoreflex drives to breathe, acid-base balance, metabolic rate and cerebral blood flow; 2) mechanical adaptations of the respiratory system obviated the anticipated rise in perceived breathlessness for a given ventilation during exercise in pregnancy, and helped to ensure that peak aerobic working capacity was admirably preserved, even in late gestation; and 3) gestational breathlessness ultimately reflected the normal awareness of increased ventilation and contractile respiratory muscle effort.

abstract: PhD


title: The multifactorial nature of hypoxia-induced drug resistance in cancer: involvement of hypoxia-inducible factor 1

contributor:
Graham, Charles H.
Anatomy and Cell Biology

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subject:
Hypoxia
Drug resistance
Cancer
Hypoxia-inducible factor 1

abstract: Thesis (Ph.D, Anatomy & Cell Biology) -- Queen's University, 2008-08-29 12:35:36.219

abstract: The development of intratumoral hypoxia is associated with resistance to therapy in many forms of human cancer, and pre-exposure of tumor cells to hypoxia confers multidrug resistance. Research over the last several years has led to considerable advances in the understanding of the cellular response to oxygen deprivation, however the hypoxia-induced mechanisms that contribute to the chemoresistance phenotype are still not well understood. Recent studies have identified hypoxia-inducible factor 1 (HIF-1), a master transcriptional regulator of oxygen homeostasis, as an important mediator of hypoxia-induced chemoresistance in cancer cells. The research described in this thesis confirms these findings and demonstrates HIF-1 is required for hypoxia-induced resistance to doxorubicin and etoposide in human tumor cells. In addition, novel findings revealed that hypoxia-induced drug resistance occurred independently of changes in the apoptotic fraction and was associated with decreased drug-induced senescence. DNA damage measured at the single-cell level revealed that the increase in survival correlated well with a HIF-1-dependent decrease in etoposide-induced DNA strand breaks, providing direct evidence that exposure of tumor cells to hypoxia leads to protection against some forms of drug-induced DNA damage. Characterization of several classical mechanisms of drug resistance upstream of DNA damage identified multiple determinants of cellular resistance to anticancer agents. The relative contributions of each varied depending on the particular drug and cancer cell line studied. Together, the findings presented here support a model in which hypoxia-induced chemoresistance is a multifactorial phenomenon that is regulated, at least in part, through HIF-1-dependent mechanisms.

abstract: PhD


title: Mechanisms inhibiting sympathetic neurotransmitter release during gastrointestinal inflammation

contributor:
Lomax, Alan E.
Physiology

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subject:
Inflammatory Bowel Disease
Colitis
Tumor Necrosis Factor
Sympathetic Regulation
Neurotransmitter Release
Voltage-Gated Calcium Channel

abstract: Thesis (Master, Physiology) -- Queen's University, 2008-09-02 12:06:20.438

abstract:
Inflammatory bowel disease (IBD) alters neuronal regulation of the gastrointestinal (GI) tract. The superior mesenteric ganglia (SMG) contain sympathetic neurons that modulate GI functions such, as motility and blood flow. IBD reduces the release of noradrenaline, a sympathetic neurotransmitter.  We hypothesized that the reduction in NA release is due to inhibition of voltage-gated calcium current (ICa), as calcium influx is a regulator of neurotransmitter release.  We also hypothesized that tumor necrosis factor α (TNFα), a proinflammatory cytokine elevated during IBD, can also inhibit the ICa of SMG neurons. Therefore, we compared ICa amplitude in neurons from normal mice and mice with dextran sulphate sodium (DSS; 5% w/v)-induced colitis.  Neurons dissociated from the SMG were cultured overnight and changes to ICa were investigated using electrophysiological, Ca2+ imaging, PCR and neurotransmitter release techniques. Colitis significantly reduced ICa of SMG neurons by selectively inhibiting N-type Ca2+ channels.   This was accompanied by a reduction in mRNA encoding the N-type channel alpha subunit (CaV 2.2) and a rightward shift in the voltage dependence of activation of ICa.  Colitis reduced the NA release from the colon and jejunum.   Depolarization-induced release of tritiated-NA was inhibited by ω-Conotoxin GVIA (300 nM). These results suggest that the changes in VGCC observed at the cell bodies of SMG neurons were also occurring at the nerve terminals during colitis.
Similar experimental techniques were performed using SMG neurons incubated overnight in TNFα (1nM). TNFα decreased ICa and depolarization-induced Ca2+ influx in SMG neurons. Similar to DSS-induced colitis, the reduction in ICa was limited to N-type Ca2+ channels.   Preincubation of neurons with SC 514 (20μM) and Bay 11 7082 (1µM), inhibitors of nuclear factor kappa B signaling, prevented the reduction in ICa. Preincubation with the p38 MAPK inhibitor, PD 169316 (30µM), recovered a smaller portion of the reduction in Ca2+ influx. These data suggest that DSS colitis and TNFα inhibit N-type VGCC ICa in sympathetic neurons and identify a novel role for NF-κB and p38 MAPK in the regulation of neurotransmitter release. These findings also suggest that DSS colitis inhibits NA release by altering sympathetic N-type VGCC in the colon and jejunum.

abstract: M.Sc.


title: A New and Improved Spin-Dependent Dark Matter Exclusion Limit Using the PICASSO Experiment

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subject:
dark matter
neutralino
direct detection
wimp

abstract: Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2008-08-29 11:42:31.428

abstract:
The PICASSO project is a direct dark matter search experiment located 2070 metres underground in SNOLAB.  Superheated droplets of Freon (C4F10) are used as the active mass, providing a target for the incoming neutralinos.  Recoiling nuclei  deposit energy in the superheated Freon droplets, triggering a phase transition, the pressure waves of which can be detected using piezo-electric sensors.

Previously published limits using an exposure of 1.98 +/- 0.19 kg day obtained a peak spin-dependent cross section exclusion limit for neutralino-proton interactions of 1.31 pb at a neutralino mass of 29 GeV/c^2 at a 90% confidence level.  Improvements in the detectors installed in the underground experiment have provided 20.99 +/- 0.25 kg day for analysis and improvements in the analysis method have produced an exclusion limit of 2.9 X 10^(-2) pb at a neutralino mass of 16.7 GeV/c^2.

In addition, a thorough study of the backgrounds, corrections and systematic uncertainties has been included, indicating that this limit does not exceed 3.5 X 10^(-2) pb when considering the one sigma error on the uncertainty band.

abstract: PhD