Review of “Dread Danger: Cowardice and Combat in the American Civil War” by Lesley J. Gordon and “Invisible Wounds: Mental Illness and Civil War Soldiers” by Dillon J. Carroll

Review of Dread Danger: Cowardice and Combat in the American Civil War by Lesley J. Gordon and Invisible Wounds: Mental Illness and Civil War Soldiers by Dillon J. Carrol

Characterization of cellulose O-acetyltransferases: Role in Biofilm Formation

Most bacterial populations reside within biofilms, which are communities of microorganisms embedded in a self-produced polymer matrix. These biofilms play critical roles in colonization and persistence within targeted niches, often contributing to disease progression. Bacterial species under specific conditions produce and export polymers that undergo post-synthesis chemical modifications, such as acetylation or the addition of phosphoethanolamine, which influence the chemical properties of the polymer, biofilm structure, and organism persistence. While well-studied systems, such as the opportunistic pathogen Pseudomonas aeruginosa, demonstrate the role of acetylation in alginate biofilms and their contribution to colonization and persistence in cystic fibrosis lungs, the mechanisms behind similar modifications in Clostridioides difficile and related pathogenic Clostridia species remained largely uncharacterized. In addition, WssI and WssF, cellulose acetyltransferases from Pseudomonas fluorescens will be functionally characterized in tandem. This research identified and characterized the role of CdCcsI, an acetyltransferase encoded within the C. difficile cellulose synthase operon (ccs), in the acetylation of cellulose biofilms along with WssI and WssF from P. fluorescens. Kinetic and enzymatic assays confirmed that CdCcsI catalyzes acetyl transfer to cellulose substrates via a catalytic triad (Ser344, Asp196, and His198) and an oxyanion hole (Arg366, Tyr367). Chromosomal mutation studies demonstrated that loss of the catalytic residues significantly reduced acetylation activity and biofilm biomass by 71%, as confirmed by iii crystal violet assays and fluorescence microscopy. Inhibitor studies identified lead compounds that effectively reduced CdCcsI activity, highlighting potential targets for antibiofilm strategies. Structural studies, including CD spectroscopy, verified that enzymatic activity loss in the active site variants was due to the specific removal of catalytic residues and not misfolding, reinforcing the functional importance of CdCcsI in acetyl-cellulose biofilm production. This work provided novel insights into the molecular mechanisms of CdCcsI, emphasizing its critical role in biofilm formation and its potential as a target for disrupting pathogenic biofilms in Clostridia. These findings elucidate the mechanisms behind biofilm modification in Clostridia and pave the way for developing strategies to weaken the biofilm barrier, enhancing antimicrobial penetration and effectiveness against infections caused by C. difficile and other Clostridial pathogens

Sustaining While Disrupting: The Challenge of Congregational Innovation

Review of Sustaining While Disrupting: The Challenge of Congregational Innovation by F. Douglas Powe Jr. and Lovett H. Weems Jr. (Minneapolis: Fortress Press, 2022

Negotiated Cultural Identity and Belonging of Self-Identified Indo-Guyanese Immigrant Women

This dissertation examines how young, self-identified Indo-Guyanese women who immigrated to Southwestern Ontario in the 1970s negotiate cultural identity and belonging. Utilizing a bio-ethnographic bricolage narrative methodology, the study explores the impact of postcolonial diaspora and social displacement on these women’s experiences within the third space or borderlands. Grounded in relativist ontology and constructivist epistemology, storytelling serves as the primary data collection method through a critical theory lens. Interviews with 12 participants were analyzed thematically and reflexively, revealing how participants construct meaning and navigate cultural identities. The analysis, conducted through feminist, decolonial, and trauma-informed perspectives, offers insights into psychological homelessness resulting from otherness. Considering the dual migrations across continents, the study employs a bricolage approach, integrating theological, epistemological, and psychological perspectives to understand generational implications and cultural straddling. As philosopher John O\u27Donohue (2002) expressed, the hunger to belong is at the heart of our nature (p. xxi). This research resonates with those exploring the generational effects of negotiated cultural identity and aims to document these lived experiences for future generations, emphasizing the preservation of diasporic cultural heritage

Review of The Hidden Victims: Civilian Casualties of Two World Wars by Cormac Ó Gráda

Review of The Hidden Victims: Civilian Casualties of Two World Wars by Cormac Ó Grád

Coupling Remote Sensing and Modelling to Monitor the Spatial Distribution and Trends of Surface Temperature and Ice Thickness on Sub-Arctic Lakes

Lake surface temperature (LST), lake ice thickness (LIT), and lake ice phenology (LIP) play significant roles in the diverse regional processes of freshwater in cold regions. They offer direct indications of regional weather and climate conditions, and their interactions with the atmosphere impact climate processes. Furthermore, lake ice is valuable to northern communities, such as those in the Northwest Territories (NWT). Ice roads, including the longest ice road in the NWT, spanning over 80 lakes, are constructed during winter to haul goods to and from industrial establishments (e.g., mines) and for travel within and between communities. A significant challenge to lakes and the ongoing use of ice roads are the changes in LST, LIT and LIP due to climate warming. Knowledge of LST, LIT, and LIP is crucial to understanding how lakes respond to climate change and determining how much weight an ice cover can safely sustain for winter travel on frozen lakes. This knowledge, however, is minimal due to the logistical difficulties in traditionally collecting measurements directly. In recent years, satellite-based observations have gained significant traction for studying lakes. However, multispectral sensors are not equipped to measure ice thickness directly, as it is a subsurface feature, which poses a limitation. Furthermore, other methods, such as one-dimensional thermodynamic lake ice models, which rely on weather station input data, are limited by the sparse availability of weather station and in-situ data, especially at high latitudes. This research adopts a multimodal monitoring approach to address these limitations by combining remote sensing data with spatially distributed modelling to study and monitor the trends and spatial distribution of LST, LIT and LIP. In this study, a retrieval algorithm was applied to the thermal bands of Landsat archives to generate a lake-specific surface temperature dataset (North Slave LST dataset) for 535 lakes in the North Slave Region (NSR), NWT, Canada, from 1984 to 2021. Cloud masks were applied to Landsat images to eliminate cloud cover. In addition, a 100 m inward buffer was used on lakes to prevent pixel mixing with shorelines. A good agreement was observed between in-situ observations and North Slave LST, with a mean bias of 0.12 °C and a root mean squared deviation (RMSD) of 1.7 °C. The North Slave LST dataset contains more available data for warmer months (May to September; 57.3 %) than colder months (October to April). The North Slave LST dataset is available at https://doi.org/10.5683/SP3/J4GMC2 (Attiah et al., 2022). Based on the North Slave LST data, LST trends and spatial distribution across the 535 predominantly small to medium lakes across NSR were studied. LST was analyzed in four distinct periods: open water season (OW), ice cover season (IC), and the transitional months of May (TM) and October (TO). The trend and relationships of LST were analyzed using the Mann-Kendall test and a multilinear regression model. The analysis revealed an overall increase in LST, with average rates (max) of 0.03 °C/year (0.05 °C/year), 0.03 °C/year (0.06 °C/year), and 0.13 °C/year (0.27 °C/year) for OW, TM, and TO, respectively across study lakes. A faster rate of change was observed in October compared to other periods. Using the North Slave LST data generated as input, a comprehensive approach was adopted to simulate the spatial variability of ice thickness on lakes at a high resolution by spatially distributing a one-dimensional thermodynamic lake ice model. The spatial distribution of LIT was modelled for study lakes from 1984 to 2022. The generated LST data, in combination with the European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA5) data, were used as inputs for the model. The model simulates the spatial distribution of daily lake ice thickness on a 50-meter spatial grid as well as the annual freeze-up and break-up dates. Results showed a root mean square deviation of LIT from 2.7 cm to 7 cm compared to in-situ data. Further analysis of ice cover on study lakes from 1984 to 2022 revealed decreasing trends in LIT (-0.26 cm/year to -0.10 cm/year) and ice cover duration (ICD) (-0.40 day/year to -0.15 day/year). Simulated LIT and freeze-up proved sensitive to morphometry (depth), while location properties (latitude/longitude) primarily drove the break-up process. This dissertation provides comprehensive approaches to deriving LST, LIT, and LIP information from small and medium lakes in data-sparse regions. A multimodal approach combining remote sensing and spatially distributed modelling is adopted to address the insufficiency of in-situ data and the sparse distribution of weather station data. The methods utilized can be replicated in other regions, providing a broader understanding of the trends and spatial distribution of LST, LIT, and LIP on sub-arctic lakes with varying physical, geographical, and morphometrical properties

Review of Empty Spaces by Jordan Abel

A book review of Jordan Abel\u27s Empty Spaces

The Impact of COVID-19 Pandemic Demands on By-law Officer Wellness and Work

This research sheds light on how the rapid demand to enforce transitioning pandemic-related (and reopening) mandates impacts the wellness of bylaw officers in the context of resource strain. Ontario bylaw officers are at the forefront of the province’s response, enforcing lockdown rules to ensure community safety. This research is imperative in understanding how bylaw officers maintain their roles in municipal enforcement, while enforcing rapidly shifting COVID-19 regulations and moving forward into a post-lockdown climate. The research focuses on identifying and understanding the demands and resources that currently typify bylaw officers working in Southern Ontario. It further examines how the COVID-19 pandemic influences the level of work commitment and engagement bylaw officers have towards their jobs. Guided by Bakker and Demerouti’s (2007) Job Demands and Resource Model (JD-R Model), which suggests that an imbalance between high demands and limited resources can lead to stress and strain, this study explores the specific job demands and resources available to Ontario bylaw officers. In using a qualitative approach to data collection and analysis, semi-structured interviews with consenting bylaw officer participants (N=8) have been conducted. The data explores the lived experiences of bylaw officers during the announcement of the Emergency Act, understanding how work demands and resources impact their mental well-being, job engagement, and commitment. This study addresses a gap in the literature by investigating bylaw officers, and it clarifies the unique demands, stressors, resources, coping well-being, and occupational performance factors that have influenced their work during the COVID-19 pandemic and post-pandemic. Moreover, the study highlights the challenges they face, such as increased job demands, insufficient resources and the emotional toll of enforcing public health measures. Additionally, it identifies coping strategies used by bylaw officers, including peer support, mental health resources, and personal coping mechanisms

The Utility of The Eye Height to Shoulder Width Ratio When Determining the Passability of an Aperture

Aperture crossing tasks are commonly used to test an individual’s perception-action integration capabilities. Multiple studies have demonstrated that young adults use body-scaled information to guide behaviours while completing a static aperture task (Franchak & Adolph, 2014; Hackney et al., 2014; Hackney & Cinelli, 2013; Warren & Whang, 1987). However, it remains unclear as to what visual information young adults are using to determine the passability of an aperture. One theory proposed by Fajen (2013), is that young adults use a ratio of their eye height (EH) to shoulder width (SW). To test this theory, eye height manipulation studies have asked participants to make perceptual judgments, which may not reflect actions or had them walk on blocks, which altered their biomechanics. Therefore, the purpose of the thesis was to determine if eye height information is used to inform a person about their body size and is utilized as the driving information source which dictates actions. It was hypothesized that an increase/decrease in eye height would lead to participants’ self-perception of shoulder width (i.e., body size) being larger or smaller respectively and give themselves more or less space to pass through safely when compared to the no manipulation condition. Collision avoidance behaviours were used to determine if a change in perception of body size occurred in two different virtual environmental tasks, those being a static aperture crossing task (Study 1) and a closing gap task (Study 2). Participants across both studies experienced the same three eye height conditions/manipulations, Normal (no EH manipulation), Tall (+30cm to EH), and Small (-30cm to EH). Eye height manipulations occurred in the VE by having the headset view of the VE increase/decrease in virtual eye height based on each participant’s normal eye height without necessarily changing gait biomechanics. Study 1; Fifteen young adults (9 male, 22.3 +/- 1.5) walked along a 7.5m long pathway in virtual reality (VR), towards a goal with an aperture created out of two vertical poles (20cm in diameter) located along the path 5m from the start. The objective of the participants was to reach the goal either by passing through or around stationary poles without rotating their shoulders or colliding with one of the 9-block randomized aperture sizes (ranging from 0.8-1.8x SW). Using head position of the participant, head position at the time of crossing (M-L), critical point, and deviation onset (A-P) were calculated. Study 2; Sixteen young adult participants (10 males; 22.2 +/- 1.6 years) walked along a 7.5m long pathway in virtual reality (VR), towards a goal with a closing doorway (initially opened to 4m wide) located along the path 3.5m from the start. The objective of the participants was to reach the goal square without rotating their shoulders or speeding up to pass through one of 9 door closing speeds relating to each participant\u27s average walking speed (0.6, 0.7, 0.75, 0.80, 0.85, 0.90, 0.95, 1.0, 1.2x walking speed). Using head position of the participant, average slow down distance from the doors, and 50% switch point were calculated. Results from both studies revealed that what information source a young adult is utilizing, will depend on the task. The results from study 1 revealed that young adults are utilizing information from their eye height to inform them about their body size while completing a static aperture task. When young adults were in the Tall condition, their self-perception of body size was wider. While the opposite was true for the Small condition, where young adults\u27 collision avoidance behaviours shifted to acting narrower. Interestingly, study 2 did not have the same results, as young adults were not utilizing eye height information when completing the closing gap task. Instead, young adults were utilizing optical variables such as beta angle as the primary information source to determine passability. The results revealed that while completing a static task that relies on body scaled information, eye height information is utilized to inform about body size to drive actions. While during a closing gap task that relies on action-scaled information, body size is disregarded, and optical information such as beta angle is utilized to determine passability

The Design and Synthesis of New Materials using Nucleophilic Aromatic Substitution Reactions

Abstract The overall objective of this research was to synthesize and study the structure-property relationships of novel polycyclic aromatic compounds capable of producing open crystalline networks based on π-stacking interactions in solid state. In this work, we describe a method of producing polycyclic aromatic compounds bearing electron-rich and electron-poor rings in order to promote cofacial π-stacking in the solid state. These compounds were synthesized from easily accessible molecules using nucleophilic aromatic substitution and copper-catalyzed aryl amination. The scope of phenoxazines bearing N-aryl substituents was explored for the synthesis of various polycyclic aromatic compounds. Interesting characteristics such as luminescence and predictable solid-state packing are displayed by electron-deficient phenoxazines. A focus was placed upon tuning the properties of the compounds by attaching phenoxazine units to different molecular architectures with the goal of producing open crystalline networks based on π-stacking interactions. The orange-colored solid compound 30 N-(4-bromophenyl) di-fluoro-di-cyano-phenoxazine was synthesized. Suzuki cross-coupling was used to attach an additional phenyl ring to compound 30 to produce compound 31. Similarly, compound 32 was synthesized by the reaction of 1, 4- benzenediboronic acid with two equivalents of compound 30. The crystal structure of compound 31revealed the presence of π-stacking interactions between the phenoxazine rings. The synthetic approach was extended to the preparation of heteropentacenes such as 52 and 58. Compound 52, which bears long alkyl chains, showed evidence of liquid crystallinity by polarized optical microscopy. However, the N-aryl heteropentacenes also showed limited stability