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Applications of Ultrafast Laser Ablation to Material Colouring and Physical Unclonable Functions
No full textAs lasers become increasingly common in both scientific and industrial settings, the list of applications for which they are utilised has grown at an incredible rate. Lasers allow the direct alteration of a near limitless number of materials with applications in nearly every current field of scientific inquiry we know. However, the nature of the interactions between these increasingly complex systems and the materials they are applied to is not always fully understood. These laser-matter interactions form an integral part of a great many laser applications including plasmonic colouring, photochemistry, cryptography, laser engraving, microfluidics, and wettability control amongst many more. Lasers offer several advantages over some processing techniques due to their flexibility to rapidly pattern areas ranging from very small, even submicron sized features, all the way up to large areas greater than tens of centimetres. However, such applications require an in depth understanding of the nature of the interactions between the irradiating laser light and the underlying substrates involved.
To that end, I have presented here several novel developments in the understanding of the nature of laser generated structures on a variety of material systems including laser coloured copper, laser generated nanoparticle based Physical Unclonable Functions (PUFs) and finally laser generated debris formation on polycarbonate. In the first publication, the interactions of plasmonic nanoparticles, oxide species and diffractive effects originating from laser-induced periodic surface structures (LIPSS) were identified as working together to yield complex far field responses which have previously been largely attributed to a single driving mechanism. The work on PUFs served to create a simplified one step process to generate nanoparticle based optical ‘fingerprints’ which combined with a simple open-source image processing algorithm serve as a simple and industrially compatible security feature. Finally, a detailed exploration of the mechanisms driving the far field colourimetric response as well as the chemical features of laser irradiated polycarbonate was developed highlighting the importance of laser repetition rate on the chemical, morphological and optical changes of the material. These results highlight the complexity and multi-faceted nature of ultrafast laser-matter interactions and indicate that the interpretation of the optical and chemical properties often requires an interplay of a variety of effects that culminate in the creation of unique and useful structures. This work also highlights that lasers can often be used to quickly generate randomized features with potential cryptographic applications that in other works often require complex or prohibitively difficult manufacturing methods in order to accomplish similar results
Enzyme Immobilization on to Magnetic Microparticles Functionalized with Polydopamine
No full textEnzymes are highly efficient biocatalysts. However, their industrial applications have been in many scenarios limited due to their narrow pH and temperature optima, poor recoverability, reusability, and stability. Immobilizing enzymes on appropriate carriers has been proven to be an effective approach addressing these issues. This thesis introduces an innovative approach utilizing polydopamine-functionalized microparticles as carriers for enzyme immobilization. The immobilization of three enzymes of vastly different molecular weights and structures, including alcalase and two lipases, was studied by experimental investigations and bioinformatic analysis. The microparticles were functionalized by coating with polydopamine (PDA), which were then grafted with either glutaraldehyde (GA) or polyethyleneimine (PEI) as the spacer for immobilization of enzymes. Various parameters, including functionalization conditions GA concentrations, enzyme properties and concentration, spacer structure and concentration, as well as immobilization conditions, were systematically investigated to assess their effects on the loading density, enzymatic activity, and specific enzymatic activity. The results revealed significant improvements in temperature and pH stability, broadening of pH and temperature optima, and improved recoverability and reusability with the immobilized alcalase maintaining 72.3% of its relative activity after 10 consecutive uses. The immobilization of the two lipases were studied using either GA or PEI as the spacer. Among various PEI molecular weights tested (600 Da, 1800 Da, and 10000 Da), PEI with a molecular weight of 600 Da provided the most effective immobilization of enzymatic proteins, while PEI with 1800 Da maintained the highest specific enzyme activities and resulted in the highest enzymatic activity per unit mass of immobilized enzymes. Optimal immobilization conditions were identified as a lipase concentration of 4.25 mg/ml, pH 6, immobilization time of 5 hours, and temperature of 10°C. The immobilized lipase demonstrated a broader optimal pH range and improved thermal stability, retaining 50% of its activity after 10 cycles of enzymatic reactions, indicating excellent reusability and stability
Development and preliminary evaluation of a decision coach training module for nurses in Norway
No full textAbstract Background Shared decision-making (SDM) is a collaborative patient-centred process for arriving at informed healthcare decisions. Decision coaching can help support SDM when combined with patient decision aids. As part of a meta-curriculum “Ready for SDM” for training different healthcare professionals in SDM, we developed and pilot-tested a new module designed to train nurses as decision coaches. The study assessed nurses' perceptions of a decision coach training module, focusing on its feasibility, acceptability and its role in developing decision coaching capabilities. Methods We used a two-phase approach guided by the Knowledge-to-Action Framework. In the first phase, we developed a decision coach training module. The second phase involved preliminary testing, using a descriptive design with qualitative and quantitative methods. We recruited a convenience sample of participants from two hospitals. Participants completed questionnaires at the end of Part A (classroom training). The assessment was informed by Kirkpatrick’s first three levels of educational outcomes: reaction (acceptability), learning (self-reported attitudes, intentions and confidence) and behaviour (practical application of decision coaching). A post-hoc inquiry investigated low participation in Part B of the coach training. Qualitative data underwent content analysis and quantitative data were analysed using descriptive statistics. Results The development resulted in a decision coach training comprising a Part A (6 h) on SDM and decision coaching fundamentals and a Part B (1 h) which involved practical application of decision coaching in the participants’ own practice (audio recorded) with self-appraisal and individualised feedback. In preliminary testing with 19 nurses from seven clinical departments, 90% of participants rated Part A as acceptable and relevant to practice. Only one nurse completed Part B due to reluctance to audio record coaching sessions. The most reported perceived barrier was time constraints. Key perceived facilitators identified were interprofessional collaboration, management support and additional practical training. Conclusion Decision coach training was feasible to deliver in the classroom. Participants reported Part A as acceptable and relevant to their practice. The second part, including an audio recording component, proved unfeasible. Further research should explore alternative methods for skill assessment and feedback in clinical practice. The results from this study will inform further refinement of the Norwegian Ready for SDM meta-curriculum and implementation strategies, particularly regarding the practical training components. Trial registration Retrospectively registered (14.02.2023) at ISRCTN (ISRCTN44143097)
Effect of Astragalus injection treatment for viral myocarditis: a systematic review and meta-analysis
No full textAbstract Background Astragalus injection has been utilized in traditional Chinese medicine to treat a variety of diseases. The purpose of this systematic review was to evaluate the effectiveness of Astragalus injection in the treatment of viral myocarditis. Methods English databases such as PubMed, Cochrane Library, and EMBASE, and Chinese databases of Sino Med, China National Knowledge Infrastructure (CNKI), the VIP Information Resource Integration Service Platform, and Wanfang Data Information Site, were searched from their inception until May 1, 2024. The outcome measures of this study included the effectiveness rate, creatine kinase (CK), aspartate aminotransferase (AST), creatine kinase Isoenzyme (CK-MB), lactate dehydrogenase (LDH), cardiac troponin I (cTnI), and electrocardiogram (ECG). Results Twenty-six studies were included in this analysis, comprising a total of 2793 patients. Meta-analyses indicated that, compared to standard treatment alone, the Astragalus injection group demonstrated significant advantages, achieving an effectiveness rate of 92.79% (1094 cases). In contrast, the control group, which included 1108 cases, had an effectiveness rate of 77.71% (861 cases). Additionally, the Astragalus injection group exhibited the following benefits for patients affected by viral myocarditis: decreasing ∆AST [weighted mean difference (WMD) = − 14.23, 95% confidence interval (CI) (− 24.17, − 4.30), P < 0.05]; ∆CK [weighted mean difference (WMD) = − 34.84, 95% confidence interval (CI) (− 48.03, − 21.65), P < 0.05], lowering ∆CK-MB [WMD = − 7.64, 95% CI (− 9.30, − 5.99), P < 0.001], ∆cTnl [WMD = − 0.18, 95% CI (− 0.27, − 0.10), P < 0.001], ∆LDH [WMD = -41.93, 95% CI (− 55.97, − 27.90), P < 0.05], and ∆cTnI [WMD = − 0.18, 95% CI (− 0.28, − 0.08), P < 0.05]. Conclusion Astragalus injection may have a therapeutic effect in patients with viral myocarditis by reducing levels of AST, CK, CK-MB, LDH, and cTnI, improving ECG results, and increasing the overall effectiveness rate for those affected by this condition. Trial registration: This study registered with PROSPERO before conducting the systematic review. The registration number is CRD42021239660
An Ethnographic Exploration of Two Catholic Communities: Thriving Through Unique Parish Cultures
No full textAbstract
This paper presents an ethnographic exploration of two Catholic communities in the
Archdiocese of Ottawa-Cornwall, conducted over a four-month period of fieldwork, against the
backdrop of declining Christianity in Canada. It examines the culture of each parish through the lens
of Geert Hofstede’s four cultural layers of organizations, providing a starting point for identifying
the characteristics of a thriving community based on Catholic ecclesiology. The study finds that the
four pillars of a thriving parish—personal encounters with Jesus Christ, synodal leadership,
catechetical formation, and missionary commitment—are deeply embedded in its unique culture.
Furthermore, it highlights the significant role of the parish priest in shaping parish life and the
potentially damaging effects of authoritarian and rigid leadership. The dissertation underscores that
every parish has its own culture and tradition, which must be respected and acknowledged.
Considering the vast tapestry of faith within the Catholic Church, this dissertation ends with a call
to cultivate a culture of intra-Catholic ecumenism among/within local Churches and parishes, which
entails respecting and recognizing one another, supporting each other, and progressing together with
a synodal spirit
Three Essays in Monetary Policy
No full textThis thesis examines critical and timely issues in monetary policy, focusing on balance sheet strategies, forward guidance, and commodity price dynamics. The first essay employs a New Keynesian Dynamic Stochastic General Equilibrium (NK-DSGE) model calibrated to Canadian data to evaluate central bank balance sheet policies during crises marked by simultaneous adverse shocks. Comparing five policy scenarios - including corridor/floor systems, quantitative easing (QE), tightening (QT), and tapering - the findings show that QE during crises followed by QT in recovery optimizes outcomes under pre-crisis corridor systems, while maintaining a floor during crises with post-crisis bond sales is superior under pre-crisis floor systems. Both strategies enhance macroeconomic stability, inflation control, and welfare.
The second essay addresses the qualitative dimension of monetary policy, particularly forward guidance, by proposing a novel identification strategy using sentiment analysis of news articles around Federal Open Market Committee (FOMC) meetings. Quantifying sentiment shifts related to interest rate guidance, balance sheet policies, and economic outlooks, it demonstrates that media-driven sentiment aligns with actual policy impacts, offering insights into expectation formation and financial market transmission. This approach mitigates endogeneity concerns in existing literature while disentangling forward guidance into its distinct components.
The third essay investigates the underexplored link between U.S. unconventional monetary policy and commodity price surges post-pandemic. Combining vector error correction models (VECM), structural VARs (SVAR), and event studies, it shows that a 1 percentage point (pp) rise in the effective federal funds rate (EFFR) reduces commodity prices by 3.66 %, while a 1 pp cut in the proxy funds rate (PFR, representing unconventional policies) increases them by 47.65 %. Short-term effects are pronounced: contractionary EFFR shocks drive a 5 % decline, while expansionary unconventional shocks yield a 20 % rise within six months. Hawkish forward guidance sentiment further amplifies speculative behavior, underscoring unconventional policy's role in commodity market volatility
Prison Pandemic Papers 2.0 – Nunavut
No full textThis dataset was collected through Access to Information requests submitted to the Government of Nunavut as part of the "COVID-19: Investigating Canada's Carceral Response to the Coronavirus through the Prison Pandemic Partnership" led by Kevin Walby (Full Professor, Criminal Justice, University of Winnipeg), Justin Piché (Full Professor, Criminology, University of Ottawa), and Abby Deshman (Executive Director, Canadian Civil Liberties Association). Initial triage of this dataset was undertaken by Mackenzie Plumb (PhD Student, Criminology, University of Ottawa).This research was funded by a Social Sciences and Humanities Research Council of Canada Partnership Engage Grant (1008-2020-0238)
Improving transitions in care for children and youth with mental health concerns: implementation and evaluation of an emergency department mental health clinical pathway
No full textAbstract Background Emergency departments (EDs) are often the first access point for children and youth seeking mental health (MH) and addiction care. However, many EDs are unprepared to manage large volumes of pediatric MH patients. In addition, the fragmented Canadian MH system is challenged in connecting youth seen in the ED for follow-up community services. A provincial Emergency Department Mental Health Clinical Pathway (EDMHCP) for children and youth presenting to the ED with MH concerns was developed to address these challenges. The objective of the current study was to determine if EDMHCP implementation resulted in: (1) pathway use, (2) more patients discharged with MH recommendations, (3) MH service recommendations that aligned with patients’ risk assessments, and (4) changes in service outcomes, including ED length of stay (LOS), revisits, and admissions/transfers. Methods We implemented the pathway at four ED sites from 2018 to 2019 using the Theoretical Domains Framework to develop a tailored strategy at each site. We conducted chart reviews retrospectively in 2017–2018 (pre-implementation) and prospectively in 2019–2020 (post-implementation). Non-parametric tests examined differences in service outcomes between the implementation periods. Results Pathway use varied widely across sites, ranging from 3.1% at site 4 to 83.0% at the lead site (site 2). More referrals to community MH agencies (p <.001) were made at discharge during post-implementation at the lead site compared to pre-implementation, and mixed results were obtained regarding whether clinicians’ risk assessments aligned with MH service recommendations. LOS significantly increased at the lead site (p <.001) and non-lead sites (sites 1, 3, 4; p =.02) between pre- and post-implementation. Revisits and admissions/transfers did not change significantly at any site. Conclusion Implementation was partially successful at the lead site, showing high pathway use and greater referrals to community MH agencies. These findings emphasize the complexity of implementing pathways in various ED settings. Successful implementation requires integration into existing workflows. Trial registration ClinicalTrials.gov (NCT02590302). Registered on 29 October 2015
Augmenting small tabular health data for training prognostic ensemble machine learning models using generative models
No full textAbstract Background Small datasets are common in health research. However, the generalization performance of machine learning models is suboptimal when the training datasets are small. To address this, data augmentation is one solution and is often used for imaging and time series data, but there are no evaluations on its potential benefits for tabular health data. Augmentation increases sample size and is seen as a form of regularization that increases the diversity of small datasets, leading them to perform better on unseen data. Objectives Evaluate data augmentation using generative models on tabular health data and assess the impact of diversity versus increasing the sample size. Methods Using 13 large health datasets, we performed a simulation to evaluate the impact of data augmentation on the prediction performance (as measured by the ROC-AUC, the area under the receiver operating characteristic curve) on binary classification gradient boosted decision tree models. Four different synthetic data generation models were evaluated. We also built a generalized linear mixed effect model to assess the variable importance for model performance improvements from augmentation. We illustrate the proposed method on seven small real datasets as an application. A comparison of augmentation with resampling (which is a proxy for a larger dataset with minimal impact on diversity) was performed. Results Augmentation improves prognostic performance for datasets that have higher cardinality categorical variables and lower baseline ROC-AUC. No specific generative model consistently outperformed the others. For the seven small application datasets, augmenting the existing data results in an increase in ROC-AUC between 4.31% (ROC-AUC from 0.71 to 0.75) and 43.23% (ROC-AUC from 0.51 to 0.73), with an average 15.55% relative improvement, demonstrating the nontrivial impact of augmentation on small datasets (p = 0.0078). Augmentation ROC-AUC was higher than resampling only ROC-AUC (p = 0.016). The diversity of augmented datasets was higher than the diversity of resampled datasets (p = 0.046). Conclusions This study demonstrates that data augmentation using generative models can have a marked benefit in terms of improved predictive performance for machine learning models on tabular health data, but only for datasets that meet baseline data complexity and predictive performance criteria. Our mixed effect model identified the most influential characteristics of the dataset and can help end-users have a more realistic expectation of the augmentation performance for a new dataset. Furthermore, augmentation performed better when having a smaller dataset, which is consistent with the argument that greater data diversity due to augmentation is beneficial. Clinical trial registration Not applicable
New Frontiers in Islamic Feminism: How Islamic Feminism is Being Shaped by Digital Media
No full textBy examining how Muslim women bloggers ground their feminism in Islam, this research disrupts oppositional framings of Islam and feminism. This study looks at how Muslim women bloggers on the Muslim Girl website highlight the feminist bent of Islamic teachings. The project asks: 1) What are some sources that contemporary North American Muslim women bloggers draw upon to (re)claim religious authority for themselves and to support feminist interpretations of Islam? And 1.1) In the North American context, what factors shape the narratives of faith that Muslim women bloggers espouse and how so? Addressing question 1, Muslim women primarily draw on Quranic verses, Hadith (Prophetic sayings) and Sunnah (Prophetic practices) to reclaim religious authority and derive feminist interpretations of Islamic teachings. Other methods for rooting women’s religious authority within Islamic precedence include referencing examples of Muslim women leaders and feminist icons, and highlighting the feminist organizational principles of early Muslim societies. As for question 1.1, Muslim women bloggers’ engagement with narratives about Islam is shaped by various factors, including prevailing perceptions about the hijab, the intersecting effects of race, sexual orientation and other axes of identity, and the contours of digital platforms through which these discourses travel. Muslim women’s lived realities are also shaped by dominant conceptualizations of masculinity and femininity, and by overarching nationalist narratives. In this terrain, Muslim women are resisting multiple interconnected systems of oppression, including patriarchy, Islamophobia, xenophobia, racism, imperialism and settler colonialism. Through their resistance, Muslim women call for transnational, intersectional and anti-racist feminism that prioritizes indigenous resistance, centers marginalized perspectives and emphasizes allyship. In other words, Muslim women foreground anti-imperialist and decolonial feminism that challenges hegemonic narratives about white saviourism and disrupts Eurocentric visions of women’s empowerment. This research also illustrates that thinking of Islam as being invariably patriarchal ignores long-standing feminist resistance in Muslim communities, resistance that is often informed by Islamic teachings