Research

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  • Biochemical Characterization of a Polysialyltransferase from Mannheimia haemolytica A2 and Comparison to Other Bacterial Polysialyltransferases
    Biochemical Characterization of a Polysialyltransferase from Mannheimia haemolytica A2 and Comparison to Other Bacterial Polysialyltransferases
    Polysialic acids are bioactive carbohydrates found in eukaryotes and some bacterial pathogens. The bacterial polysialyltransferases (PSTs), which catalyze the synthesis of polysialic acid capsules, have previously been identified in select strains of Escherichia coli and Neisseria meningitidis and are classified in the Carbohydrate-Active enZYmes Database as glycosyltransferase family GT-38. In this study using DNA sequence analysis and functional characterization we have identified a novel polysialyltransferase from the bovine/ovine pathogen Mannheimia haemolytica A2 (PSTMh). The enzyme was expressed in recombinant form as a soluble maltose-binding-protein fusion in parallel with the related PSTs from E. coli K1 and N. meningitidis group B in order to perform a side-by-side comparison. Biochemical properties including solubility, acceptor preference, reaction pH optima, thermostability, kinetics, and product chain length for the enzymes were compared using a synthetic fluorescent acceptor molecule. PSTMh exhibited biochemical properties that make it an attractive candidate for chemi-enzymatic synthesis applications of polysialic acid. The activity of PSTMh was examined on a model glycoprotein and the surface of a neuroprogenitor cell line where the results supported its development for use in applications to therapeutic protein modification and cell surface glycan remodelling to enable cell migration at implantation sites to promote wound healing. The three PSTs examined here demonstrated different properties that would each be useful to therapeutic applications., Lindhout T, Bainbridge CR, Costain WJ, Gilbert M, Wakarchuk WW (2013) Biochemical Characterization of a Polysialyltransferase from Mannheimia haemolytica A2 and Comparison to Other Bacterial Polysialyltransferases. PLoS ONE 8(7): e69888.
    Biofilms' Role in Planktonic Cell Proliferation
    Biofilms' Role in Planktonic Cell Proliferation
    The detachment of single cells from biofilms is an intrinsic part of this surface-associated mode of bacterial existence. Pseudomonas sp. strain CT07gfp biofilms, cultivated in microfluidic channels under continuous flow conditions, were subjected to a range of liquid shear stresses (9.42 mPa to 320 mPa). The number of detached planktonic cells was quantified from the effluent at 24-h intervals, while average biofilm thickness and biofilm surface area were determined by confocal laser scanning microscopy and image analysis. Biofilm accumulation proceeded at the highest applied shear stress, while similar rates of planktonic cell detachment was maintained for biofilms of the same age subjected to the range of average shear rates. The conventional view of liquid-mediated shear leading to the passive erosion of single cells from the biofilm surface, disregards the active contribution of attached cell metabolism and growth to the observed detachment rates. As a complement to the conventional conceptual biofilm models, the existence of a biofilm surface-associated zone of planktonic cell proliferation is proposed to highlight the need to expand the traditional perception of biofilms as promoting microbial survival, to include the potential of biofilms to contribute to microbial proliferation., Bester, E., Wolfaardt, G. M., Aznaveh, N. B., & Greener, J. (2013). Biofilms' role in planktonic cell proliferation. International Journal of Molecular Sciences, 14(11), 21965-21982. doi:10.3390/ijms141121965, (This article belongs to the Special Issue Biofilms: Extracellular Bastions of Bacteria)
    Biomechanical assessment of composite versus metallic intramedullary nailing system in femoral shaft fractures: A finite element study
    Biomechanical assessment of composite versus metallic intramedullary nailing system in femoral shaft fractures: A finite element study
    Background: Intramedullary nails are the primary choice for treating long bone fractures. However, complications following nail surgery including non-union, delayed union, and fracture of the bone or the implant still exist. Reducing nail stiffness while still maintaining sufficient stability seems to be the ideal solution to overcome the above mentioned complications. Methods: In this study, a new hybrid concept for nails made of carbon fibers/ fl ax/epoxy was developed in order to reduce stress shielding. The mechanical performance of this new implant in terms of fracture stability and load sharing was assessed using a comprehensive non-linear FE model. This model considers several mechanical factors in nine fracture configurations at immediately post-operative, and in the healed bone stages. Results: Post-operative results showed that the hybrid composite nail increases the average normal force at the fracture site by 319.23 N ( P b 0.05), and the mean stress in the vicinity of fracture by 2.11 MPa ( P b 0.05) at 45% gait cycle, while only 0.33 mm and 0.39 mm ( P b 0.05) increases in the fracture opening and the fragments' shear movement were observed. The healed bone results revealed that implantation of the titanium nail caused 20.2% reduction in bone stiffness, while the composite nail lowered the stiffness by 11.8% as compared to an intact femur. Interpretation: Our results suggest that the composite nail can provide a preferred mechanical environment for healing, particularly in transverse shaft fractures. This may help bioengineers better understand the biomechanics of fracture healing, and aid in the design of effective implants., Samiezadeh, S., Avval, P. T., Fawaz, Z., and Bougherara, H. Biomechanical assessment of composite versus metallic intramedullary nailing system in femoral shaft fractures: A finite element study. Clin. Biomech. 2014; 29(7): 803–810.
    Bird harvesting practices and knowledge, risk perceptions, and attitudes regarding avian influenza among Canadian First Nations subsistence hunters: implications for influenza pandemic plans
    Bird harvesting practices and knowledge, risk perceptions, and attitudes regarding avian influenza among Canadian First Nations subsistence hunters: implications for influenza pandemic plans
    Background There is concern of avian influenza virus (AIV) infections in humans. Subsistence hunters may be a potential risk group for AIV infections as they frequently come into close contact with wild birds and the aquatic habitats of birds while harvesting. This study aimed to examine if knowledge and risk perception of avian influenza influenced the use of protective measures and attitudes about hunting influenza-infected birds among subsistence hunters. Methods Using a community-based participatory research approach, a cross-sectional survey was conducted with current subsistence hunters (n = 106) residing in a remote and isolated First Nations community in northern Ontario, Canada from November 10–25, 2013. Simple descriptive statistics, cross-tabulations, and analysis of variance (ANOVA) were used to examine the distributions and relationships between variables. Written responses were deductively analyzed. Results ANOVA showed that males hunted significantly more birds per year than did females (F1,96 = 12.1; p = 0.001) and that those who hunted significantly more days per year did not perceive a risk of AIV infection (F1,94 = 4.4; p = 0.040). Hunters engaged in bird harvesting practices that could expose them to AIVs, namely by cleaning, plucking, and gutting birds and having direct contact with water. It was reported that 18 (17.0%) hunters wore gloves and 2 (1.9%) hunters wore goggles while processing birds. The majority of hunters washed their hands (n = 105; 99.1%) and sanitized their equipment (n = 69; 65.1%) after processing birds. More than half of the participants reported being aware of avian influenza, while almost one third perceived a risk of AIV infection while harvesting birds. Participants aware of avian influenza were more likely to perceive a risk of AIV infection while harvesting birds. Our results suggest that knowledge positively influenced the use of a recommended protective measure. Regarding attitudes, the frequency of participants who would cease harvesting birds was highest if avian influenza was detected in regional birds (n = 55; 51.9%). Conclusions Our study indicated a need for more education about avian influenza and precautionary behaviours that are culturally-appropriate. First Nations subsistence hunters should be considered an avian influenza risk group and have associated special considerations included in future influenza pandemic plans., Charania, N. A., Martin, I. D., Liberda, E. N., Meldrum, R., & Tsuji, L. J. S. (2014). Bird harvesting practices and knowledge, risk perceptions, and attitudes regarding avian influenza among canadian first nations subsistence hunters: Implications for influenza pandemic plans. BMC Public Health, 14(1), 1113. doi:10.1186/1471-2458-14-1113
    Board renewal and rejuvenation
    Board renewal and rejuvenation
    [First paragraph of Introduction]: Organizations change, sometimes incrementally and sometimes in a discontinuous manner that makes the past an irrelevant predictor of the future. Large, wrenching changes make past behaviour and governance less relevant and call for a new perspective and a new board leadership. Often these changes are brought about by the external environment, which may no longer value the services provided, or economic pressure may reduce the priority of funding. For example, public funding of broadcasting is being reduced across North America and the debate about public funding for broadcasting is beginning. The not-for-profit organization is caught up in the social and economic changes taking place around the world. This phenomenon is not exclusive to any particular country or province, but is part of a much wider change. Keywords: CVSS, Centre for Voluntary Sector Studies, Working Paper Series,TRSM, Ted Rogers School of Management Citation:, Jensen, K. (1996). Board Renewal and Rejuvenation. (Working Paper Series Volume 1996 (2)). Toronto : Ted Rogers School of Management, Centre for Volunteer Sector Studies, Ryerson University.
    Branding Higher Education for Student Recruitment: A Shift From Academia to Career-Focused Education
    Branding Higher Education for Student Recruitment: A Shift From Academia to Career-Focused Education
    This major research paper analyzes the data coded across Ryerson’s digital and social media student recruitment platforms to identify what main messages Ryerson communicates during application and enrollment periods for students. The following research questions help guide the study: What messages does Ryerson communicate about itself in the mission statement and recruitment platforms in Why Ryerson’s Facebook page, Why Ryerson’s blog posts and the Undergraduate tab on Ryerson’s website? In what ways do Ryerson’s primary branding messages change across its different social media and digital platforms? Hsieh and Shannon’s (2005) conventional qualitative content analysis was used to analyze the data coded in Ryerson’s mission statement, the Undergraduate tab on the Ryerson website, the Why Ryerson Facebook page and the Why Ryerson blog during the Ontario University Fair and March Break Open House student recruitment time periods. The study led to identify the main messages Ryerson communicates during student recruitment time periods and additional patterns and themes that were not directly informed by the literature.
    Breast cancer screening disparities among immigrant women by world region of origin: a population-based study in Ontario, Canada
    Breast cancer screening disparities among immigrant women by world region of origin: a population-based study in Ontario, Canada
    Background Breast cancer is one of the leading cause of mortality and morbidity in Canada. Screening is the most promising approach in identification and treatment of the disease at early stage of its development. Research shows higher rate of breast cancer mortality among ethno-racial immigrant women despite their lower incidence which suggests disparities in mammography screening. This study aimed to compare the prevalence of appropriate mammography screening among immigrant and native borne women and determine predicators of low mammography screening. Methods We conducted secondary data analyses on Ontario linked social and health databases to determine the proportion of women who were screened during the two- year period of 2010-2012 among 1.4 million screening-eligible women living in urban centres in Ontario. We used multivariate Poisson regression to adjust for various socio-demographic, health care-related and migration related variables. Results 64 % of eligible women were appropriately screened. Screening rates were lowest among new and recent immigrants compared to referent group (Canadian-born women and immigrant who arrived before 1985) (Adjusted Rate Ratio (ARR) (0.87, 95 % CI 0.85 -0.88 for new immigrants and 0.90, 95 % CI 0.89-0.91 for recent immigrants. Factors that were associated with lower rates of screening included living in low- income neighborhoods, having a male physician, having internationally- trained physician and not being enrolled in primary care patient enrolment models. Those not enrolled were 22 % less likely to be screened compared to those who were (ARR 0.78, 95 % CI 0.77-0.79). Conclusion To enhance immigrant women screening rates efforts should made to increase their access to primary care patient enrolment models and preferably female health professionals. Support should be provided to interventions that address screening barriers like language, acculturation limitations and knowledge deficit. Health professionals need to be educated and take an active role in offering screening guidelines during health encounters., Vahabi, M., Lofters, A., Kumar, 7., & Glazier, R. H. (2015). Breast cancer screening disparities among urban immigrants: A population-based study in Ontario, Canada. BMC Public Health, 15, 679.
    Bridging divides : what can cities do? a summary of the public forum held on May 13, 2015,
at Ryerson University
    Bridging divides : what can cities do? a summary of the public forum held on May 13, 2015, at Ryerson University
    Our cities are facing growing divides such as uneven access to services and housing, congestion and transit shortfalls, income polarisation, and political divisions. This project brings together experts across disciplines to collaborate and develop solutions for actionable change in the GTHA. This report summarizes this unique public forum where three GTA mayors joined urban experts to propose strategies aimed at bridging the growing divides in our cities., Ryerson City Building Institute. (2015). Bridging divides : what can cities do? a summary of the public forum held on May 13, 2015, at Ryerson University. Toronto : Ryerson City Building Institute.
    Bridging the Theory/Practice Divide: Experiential Learning for a Critical, People-Centred Economy
    Bridging the Theory/Practice Divide: Experiential Learning for a Critical, People-Centred Economy
    This report provides an overview and analysis of the current understanding of how “experiential learning” is conceptualized, implemented and evaluated in professional service fields of study. Better understanding of this educational approach will benefit educators as well as students. Experiential learning is an integral part of the authors’ institutional culture: 90% of all undergraduate programs include an experiential learning component (Learning and Teaching Office, Ryerson University, 2015). Experiential learning is also rapidly expanding in other Ontario universities (Council of Ontario Universities, 2014). Despite its prevalent use, the field of experiential learning remains under-researched and the research that has been done is fragmented. There is a lack of evidence to support the extent to which this type of learning bridges the gap between theory and practice, broadens career prospects, and contributes to the development of students’ critical thinking skills. This report focuses on the nine professional fields associated with the Faculty of Community Services, Ryerson University: Child and Youth Care, Disability Studies, Early Childhood Studies, Midwifery, Nursing, Nutrition, Public and Occupational Health, Regional and Urban Planning and Social work. (Executive Summary, page 3)
    Bringing a small archival collection to life on the web:  remembering the Real Winnie
    Bringing a small archival collection to life on the web: remembering the Real Winnie
    The purpose of this poster is to provide insight into the processes involved in creating an interdisciplinary online exhibition focused on a unique chapter of Canadian history from World War I. The exhibition focuses on the Colebourn Family Archive comprising digitized photographs and ephemera of Canadian soldier and veterinarian Harry Colebourn (1887–1947) who purchased a pet bear named Winnie who later became A. A. Milne’s inspiration for the classic Winnie-the-Pooh children's book series, Wilson, Sally, & Marina Morgan (2015). Bringing a small archival collection to life on the web: remembering the real Winnie: Proceeding of the International Conference on Dublin Core and Metadata Applications, 2015.
    Broadband Internet Usage Outside the Home: Insights from a Study of Toronto Internet Cafes
    Broadband Internet Usage Outside the Home: Insights from a Study of Toronto Internet Cafes
    This paper addresses a simple question. In an environment where more and more people have broadband internet access at home, what is the role of internet cafés? In answering this question, a contribution is made to the limited existing knowledge of how consumers use public internet points, with a specific focus on how broadband services are used. This study is novel because work to date has focused on understanding how consumers use broadband in their homes, with the assumption being that once everyone has residential broadband connectivity, public access points like internet cafés will disappear. This paper offers a description of user behaviours observed in 28 internet cafés and 4 free public access points. The paper documents diversity in users and usage patterns, and suggests that internet cafés continue to offer valuable services to their users. Broadband connectivity is used for gaming, but few other uses that required broadband connectivity were observed., Paper presented at the International Telecommunications Society Asia-Australasian Regional Conference, Perth, Australia.
    Build it and the women will come? WTSN and the advent of Canadian digital television
    Build it and the women will come? WTSN and the advent of Canadian digital television
    Abstract: In fall 2001, over 200 digital television channels were launched in Canada. One of those channels was WTSN (Women's Television Sports Network)-the world's first 24- hour television network exclusively dedicated to broadcasting women's sports. In the fall of 2003, however, WTSN ceased broadcasting operations. This analysis of CRTC policies and personal interview data with Canadian media members argues that while the demise of WTSN can be attributed to the unfortunate pitfalls associated with early digital television rollout and cultural policies, the network's downfall is best explained in substantially more ideological terms. From the outset, WTSN entered uncharted waters in the Canadian television sport landscape, attempting to showcase women's sports to a predominantly female audience-a demographic that has yet to materialize for mainstream sports programming. Résumé : En automne 2001 au Canada a lieu la lancée de plus de 200 chaînes de télévision numériques. Une de ces chaînes est WTSN (Women's Television Sports Network), le premier réseau de télévision au monde entièrement dédié à la diffusion des sports féminins 24 heures sur 24. WTSN, cependant, disparaît des ondes dès l'automne 2003. Cette analyse des politiques du CRTC et d'entrevues menées par l'auteur auprès de professionnels des médias canadiens soutient que, bien qu'on puisse attribuer l'échec de WTSN à certaines politiques culturelles ainsi qu'aux problèmes reliés à l'expansion trop hâtive de la télévision numérique à l'époque, on peut aussi tirer avantage d'une approche plus idéologique pour expliquer la disparition de ce réseau. En effet, en offrant les sports pour femmes à un public composé majoritairement de femmes, WTSN dès ses débuts s'est aventuré dans un territoire inconnu par l'univers des sports sur les ondes canadiennes, la majorité des femmes n'ayant pas encore montré un intérêt soutenu pour la programmation sportive à grand public., Neverson, N. (2010). Build It and the Women Will Come? WTSN and the Advent of Canadian Digital Television. Canadian Journal Of Communication, 35(1). Retrieved from http://www.cjc-online.ca/index.php/journal/article/view/2246/2990