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H₂S mediates the protective roles of polysulfides against lipopolysaccharide-induced vascular smooth muscle cell dysfunctions
No full textHydrogen sulfide (H₂S), a gaseous signaling molecule, exerts protective effects in cardiovascular and inflammatory diseases. Polysulfides (e.g., Na₂S₂, Na₂S₃, Na₂S₄), as reactive sulfur species, exhibit unique redox behavior and may serve as slow-releasing H2S donors. Lipopolysaccharide (LPS), a potent endotoxin from Gram-negative bacteria, induces vascular inflammation and smooth muscle cell (SMC) dysfunction, contributing to sepsis-associated cardiovascular complications. Yet the roles of polysulfides in LPS-induced SMC dysfunctions remain unclear. This study evaluated the H₂S-releasing capacities of these polysulfides and their impact on LPS-induced alterations in mouse SMCs. Utilizing biochemical assays and cell imaging techniques, we found that H₂S can be spontaneously released from Na₂S₂, and this release can be significantly enhanced in the presence of cysteine. Both Na₂S₂ and NaHS (a well-known H₂S-releasing donor) inhibited the growth of both Gram-negative and Gram-positive bacteria. Also, we discovered that LPS treatment (10 ng/mL) induced SMC proliferation, oxidative stress, and upregulation of pro-inflammatory genes (IL-2, IL-4, TNF-α). Notably, Na₂S₂ elevated intracellular H₂S levels and reversed LPS-induced functional and inflammatory changes in SMCs. These findings highlight Na₂S₂ as a bioactive, thiol-sensitive H₂S donor capable of mitigating LPS-induced vascular inflammation and SMC dysfunctions
The biological impact of heavy metals pollution from mining communities in Ghana : a review with a comparative analysis to Canada
No full textIn this critical review, the biological impact of heavy metals pollution from mining communities in Ghana is examined and compared to that of Canada. Ghana faces serious health problems, such as neurological disorders and cancers, because of the high levels of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) brought about by artisanal and small-scale gold mining (ASGM). Similarly, mining operations in Canada lead to large-scale contamination, yet the effects are lessened to some extent by sophisticated technologies and more stringent regulations. Moreover, both Ghana and Canada suffer from ecological issues, including water pollution and soil degradation, that disrupt indigenous flora and fauna. Yet, there are still differences identified between these two countries, which are mainly brought about by different environmental conditions, regulatory systems, and mining practices. This critical review thus explores the pressing need to implement more rigid regulations and better waste management in Ghana. It also discusses the urgency of resolving Canada’s legacy pollution issue. Future studies must therefore address innovative remediation procedures and sustainable mining methods to alleviate heavy metals pollution in both Ghana and Canada
Biodegradation of polyethylene terephthalate (PET) : a critical review
No full textPolyethylene terephthalate (PET) is a highly persistent plastic pollutant that undergoes minimal natural degradation, prompting increasing interest in biological strategies as alternatives to conventional recycling methods. This critical review systematically analyzed 152 peer-reviewed studies, categorized into four methodological groups: enzyme-only, microbial-only, combined, and unconventional approaches to PET biodegradation. Studies were identified through structured searches and selected based on relevance, methodological quality, and availability of degradation data. Enzymatic systems - particularly engineered variants of PETase and cutinase - demonstrated high depolymerization efficiencies under optimized laboratory conditions. Microbial approaches effectively metabolized PET breakdown products across diverse environments but generally exhibited slower performance. Hybrid systems integrating enzymes, microorganisms, or pretreatments showed enhanced overall conversion, while unconventional strategies offered proof-of-concept insights with limited validation. Despite these advances, key challenges remain, including the lack of standardized degradation metrics, difficulties in scaling processes, and inconsistent substrate characterization. This review consolidates existing findings into systematic pathways, highlights recurring limitations, and outlines application contexts. The future of PET biodegradation will depend on continued innovations in enzyme engineering, microbial design, and integrated systems, with emphasis on improving efficiency and scalability to enable practical, real-world implementation within sustainable plastic waste management frameworks
User-controlled adaptable residential building in Vancouver: biomimetic strategies for Ssustainable cooling
No full textBuildings, like living organisms, can adapt, breathe, and exist in harmony with their surroundings. Nature has perfected the art of resilience. Plants, for example, have developed smart ways to adjust to changing climates, use energy efficiently, and maintain balance in their ecosystems. This thesis takes inspiration from biomimicry through the design of a high-rise, mixed-use residential building in Vancouver that will incorporate a user- controlled and adaptable facade system, which will improve natural ventilation and solar shading. This research explores sustainable cooling methods through adaptable architectural elements that allow users to actively change their indoor environment, and by incorporating cross-ventilation, the building will enhance airflow. Moreover, the use of locally sourced and resilient materials will offer durability in the city’s humid climate.
Beyond biomimicry, this study draws inspiration from Indigenous design traditions. influenced by First Nations weaving techniques, the design reflects cultural heritage and strengthens the building’s connection to its environment. This approach creates a relationship between people, architecture, and nature, where adaptation is not just a feature but a necessity for sustainable living
Cradle to soil: rethinking furniture design for environmental impact
No full textThis thesis explores the environmental impact of the furniture industry which contributes a significant amount of waste production in Canada. With a focus on sustainability, this study addresses the industry’s overproduction, overconsumption and reliance on non-regenerative materials. This current design method instilled a culture that is termed Cradle to Grave, where everyday products are designed to be obsolete, bound for the landfill before it is even consumed. The thesis critiques the Cradle to Cradle earlier design model and advocates for a shift toward a lower environmental impact framework, the Cradle to Soil approach. This concept, building on the Cradle to Cradle theory by William McDonough and Michael Braungart, prioritizes disassembly, reuse, modularity, and the use of organic materials to reduce environmental harm. The research focuses on the Laurentian University McEwen School of Architecture as a site, studying the current furniture pieces in the school and designing new furniture that is built for longevity and eventually returned to the earth to enrich the soil by using organic materials. By integrating these principles, it aims to create functional and culturally relevant furniture while promoting a circular economy, sustainable design choice and mitigating waste within the site
Ébauche de plan de livre de récit de vie pour favoriser la continuité culturelle des enfants Inuit placés
No full textAu Québec, les enfants Inuit1 sont largement surreprésentés dans le système de protection de la jeunesse. Trop souvent, les placements se font en dehors de leur communauté et de leur culture, ce qui contribue à un déracinement identitaire et à la rupture des liens familiaux et culturels. Ce constat nous oblige à repenser les pratiques en protection de la jeunesse pour favoriser la continuité culturelle.
Cet essai décrit un stage spécialisé, réalisé en collaboration avec le Centre de santé Tulattavik (CSTU) et Nunavimmi Ilagiit Papatauvinga (NIP) à Kuujjuaq, qui représente une démarche inductive et réflexive, fondée sur un cadre théorique combinant l'approche structurelle et l'approche à double perspective, et de continuité culturelle, et inspirée d'un processus de recherche autochtone basé sur le relationnel, pour explorer les thèmes et éléments culturels essentiels à inclure dans coconstruction d'une ébauche de livre de récit de vie pour les enfants Inuit placés sous la protection de la jeunesse. Deux ateliers en cercle de partage, lun en présentiel et l'autre en virtuel, ont mené à la coconstruction d'une ébauche de plan détaillé du livre de récit de vie Inuit dans une perspective d'autodétermination qui a permis d'enchainer un processus visant à donner la possibilité aux enfants Inuit placés en famille d'accueil Inuit et qallunaat de recueillir les éléments essentiels pour favoriser la continuité culturelle
Controls on volcanogenic massive sulphide deposits in the Kamiskotia area, Timmins, ON
No full textThe Kamiskotia area is a volcanogenic massive sulphide (VMS) district in the Abitibi greenstone belt. Past-producing VMS deposits in this area are hosted by the Neo-Archean Blake River assemblage and share several similarities (e.g., comparable bimodal host lithologies, alteration signatures, deposit morphology, stratigraphic position, and ore assemblages) to suggest further mineralization potential. However, no significant deposit has been uncovered since the initial discoveries of the past-producing mines in the 1920s and traditional prospecting is inhibited by relatively low outcrop exposures. This study seeks to describe in detail the geochemical characteristics of >10,000 lithogeochemical data points and to determine if the volcanic units in the study area have geochemical signatures characteristic of VMS mineralization. This study also uses mineral prospectivity mapping (MPM) to identify potential exploration targets. Random forest (RF) was used to integrate predictor maps from lithologic, structural, geophysical, and geochemical data prepared in both continuous and binary surface map formats.
Lithogeochemical analyses reveal two general mafic groups (1 and 2) and four rhyolite groups (1– 4) for most assemblages, based on TiO2, P2O5, and Zr plots. The mafic to intermediate rocks are predominantly tholeiitic to transitional basalts and basaltic andesites with MORB-like magma affinities based on the TiO2/Yb proxy. The Th/Nb ratio suggests an interaction of the mafic magmas with existing hydrated crust, resulting in crustal contamination, except for Tisdale mafic samples. Mafic rocks with an evolved signature (i.e., P2O5 > 0.3 wt %, TiO2 > 2.2 wt %, high rare earth element concentrations, and relatively flat chondrite normalized patterns) were also distinguished from their primitive counterparts, except for Tisdale mafic samples. Felsic samples are mainly tholeiitic to transitional rhyolite-dacites, with more fractionated rare-earth element patterns. The rhyolites are predominantly of the fertile high-silica-Zr, FII-FIII type. These geochemical signatures are associated with fertile bimodal-mafic VMS systems. Computed mass changes and alteration indices show that mafic samples and rhyolites from Upper and Lower Blake River assemblages have the greatest degrees of hydrothermal alteration.
The probability map from continuous predictor maps (continuous MPM) and binary predictor maps (binary MPM) showed high overall classification accuracies (i.e., > 85 %), success rates of classification and prediction, and area under the curve (AUC) on efficiency curves. The success rates and AUCs obtained were higher for the binary MPM than the continuous MPM, suggesting that binary predictor maps outperform continuous maps. The binary MPM was, therefore, selected as the best performer. Ten areas with probabilities greater than 90 % were highlighted as the most prospective areas, out of which six were interpreted as new potential targets away from past-producing mines that may be prime for follow-up. RF ranks predictor maps from subvolcanic-synvolcanic intrusions and faults, mafic and felsic volcanic lithologies, Bouguer gravity and its derivatives, high-Zr rhyolites, evolved mafic rocks, Cu, Zn, and chloritization indices as the most important parameters to consider for follow-up studies in these areas. The results underscore the usefulness of RF MPM in integrating multiple geoscience datasets to map VMS prospectivity and exhibit the potential for new discoveries in the Kamiskotia area.
Based on the presence of (i) contaminated, MORB, and Fe-Ti mafic signatures, (ii) high-Zr, high-silica, and FIII rhyolites with WPG signatures, (iii) high alteration indices (AI and CCPI) with corresponding high mass change intensities, and (iv) high RF probability areas, it is likely that the Upper Blake River, Lower Blake River, and Upper Kidd-Munro assemblages have the best potentials for VMS followed by Lower Kidd-Munro and Deloro. The Tisdale assemblage in the study area may have the lowest potential.International Explorers and Prospectors (IEP), Mineral Exploration Research center (MERC
Mineralogical, textural, and chemical thermodynamic constraints of the Crawford Ni-Co-(PGE) deposit, Abitibi greenstone belt, Superior Province, Ontario, Canada
No full textThe 2704 ± 0.88 Ma Crawford Ni-Co-(PGE) deposit, located 50 km north of Timmins, is hosted in a mafic-ultramafic intrusion emplaced within volcanic rocks of the Stoughton-Roquemaure assemblage in the Abitibi greenstone belt. The intrusion shows progressive stages of serpentinization, and nickel mineralization occurs dominantly in the dunitic section of the intrusion as disseminated to patchy net-textured assemblages containing pentlandite, heazlewoodite, and awaruite. The deposit is dissected into two bodies (the western body and the eastern body) by a Proterozoic N-NW sinistral strike-slip fault. An assumed Archean fault cuts the eastern body parallel its dunitic-peridotitic core. The main goal of the project was to document the effects of serpentinization and extract mineralogical and geochemical parameters from present mineral assemblages to better understand mineralization processes and assist in locating and evaluating similar deposits elsewhere. Ninety-one samples were collected from eight drill holes based on core-logging and preliminary petrography. The suite of samples collected includes dunite, peridotite, pyroxenite, and gabbro. However, the focus of the work was on the dunitic samples since those are the intervals hosting the Ni mineralization. The mineralogy and textures were characterized using optical microscopy and SEM-EDS. A subset of samples was analyzed by EPMA. The results show that the dunites were almost monomineralic adcumulates consisting of subhedral olivine, typically containing less than 5% pyroxene, chromium spinel, and primary sulfides. Samples from the East zone are completely serpentinized, whereas samples from the Main-West zone range from completely serpentinized near a fault to approximately 20% towards the western margin of the intrusion and away from a fault. Serpentinization also affected accessory minerals. Samples from the Main-West zones record the progressive destruction of primary olivine and pentlandite during serpentinization and the appearance of secondary heazlewoodite and awaruite. Completely serpentinized samples contain heazlewoodite, awaruite, and secondary magnetite, but only minor relict pentlandite. Native copper was observed in some samples and was used to assess changes in sulfur and oxygen fugacity during serpentinization. Olivine composition could be extracted from samples where primary olivine was preserved. On average, olivine grains are Fo88 ± 1 and have 2,800 ± 350 ppm Ni (average range: 2,200 to 3,380 ppm). Nickel-bearing mineral composition yields Fe4.6Ni4.1S8 for pentlandite (i.e., with an Fe:Ni ratio close to 1:1), stoichiometric heazlewoodite (Ni3S2), and Ni2.5Fe for awaruite. Rare primary Cr-spinel (Mg# 0.53 ± 0.08; Cr# 0.67 ± 0.02) is mostly preserved but secondary magnetite is also present. The mineralogical changes indicate loss of sulfur during serpentinization, mobilization of Fe, Ni, and Cu, and the release of Ni previously locked in the olivine structure. The relatively high Ni content in olivine and nearly monomineralic nature of the dunite layers indicate that the Ni liberated from olivine during serpentinization could become part of the Ni in secondary Ni-bearing minerals. However, as expected, the original (magmatic) pentlandite content largely controls the bulk nickel content in the system. Desulfurization of primary pentlandite, linked to the effects of serpentinization, results in formation of secondary Ni-bearing minerals and increasing in the Ni:S values in the target rocks.Canada Nickel Company (CNC), Natural Sciences and Engineering Research Council of Canada (NSERC), Mineral Exploration Research Center (MERC
Organic Polyradicals: Synthesis, Characterization and Application
No full textOrganic polyradicals, a fascinating class of compounds characterized by the presence of multiple unpaired electrons, are gaining increased attention from researchers as potential materials in various scientific and technological fields due to their distinct redox-active properties. This critical review focuses on the synthesis and characterization of two distinct types, polymeric and large/macro molecular organic polyradicals. In addition, their applications in energy storage, catalysis, and biomedical sciences are outlined. Various synthetic strategies, including radical polymerization, post-polymerization modification, and template-assisted synthesis are explored. Subsequently, particular emphasis is given to the synthesis of conducting materials bearing stable radicals as an emerging class of functional materials with enhanced redox properties. This critical review essay underscores the potential of organic polyradicals as a versatile class of compounds for driving significant advancements in chemical science and technology
Aesthetic diversity in wood architecture
No full textThis thesis discusses a research/design project entitled Aesthetic Diversity in Wood Architecture. The research explores methods of workmanship and lumber sourcing toward developing architecture that maintains and expresses the aesthetic diversity of the forest. The objective of this research is to address the gap that currently exists in the discourse of architecture related to the application of intimate workmanship methods to achieve buildings that are aesthetically diverse and inherently express the conditions of a forest. Theories from David Pye and George Nakashima inform a research-creation methodology that applies hands- on workmanship methods to self-sourced lumber containing characteristics such as rot and bug holes. Through this methodology, small-to-large scale artifacts are produced, informing the design of a building sited within the northern forest context of Sudbury, Ontario