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The impacts of artificial light at night (ALAN) spectral composition on key behavioral traits of a sandy beach isopod
No full textArtificial light at night (ALAN) is a widespread human-induced disturbance, whose effects have been documented in many ecosystems. However, limited attention has been given to the source of the lights behind ALAN, so this study examined three of them: High-Pressure Sodium (HPS) lamps and warm and cool white Light-Emitting Diodes (LEDs). Laboratory experiments compared the effects of each type of light to natural day/night conditions, upon the activity, feeding behavior and growth of the isopod Tylos spinulosus. Tanks equipped with actographs monitored locomotor activity, while separate tanks were utilized to assess food consumption and growth under natural and ALAN conditions. Our results show that all ALAN sources disrupt and reduce isopods' activity and feeding behavior, with cool and warm LEDs being the most severe and mildest, respectively. Instead, ALAN had only minor effects on isopod growth. Our findings suggest that warm LEDs may be preferable for ALAN mitigation purposes.FONDECYT Gran
The giant Irish moss: contribution to local biodiversity and susceptibility to raising temperatures in a marine protected area
No full textClimate change, as a world-wide phenomenon, has accelerated the rate at which many species are going locally extinct. This is especially true in shallow coastal areas, home to an array of habitat modifying species known as ecosystem engineers for their ability to modify or create habitats. Many of these species are exposed to a variety of terrestrial and marine stressors (e.g., agriculture runoff, organic pollution, and ocean warming), therefore their study and conservation is a critical part of climate change research. One such ecosystem engineer, found exclusively in a Marine Protected Area (MPA) on Prince Edward Island, Atlantic Canada, is the giant Irish moss (Chondrus crispus). As a unique strain of the widespread Irish moss, this marine alga has broader fronds and lacks a holdfast, relying on a close association with blue mussels (Mytilus edulis) whose byssal threads anchor the alga to the seafloor. The giant Irish moss population experienced serious declines for over two decades, becoming almost extinct early in the 2000s, and prevailing as small patches (clumps) within certain areas the MPA. The limited knowledge of this strain raises two important questions: what the potential contribution of these clumps to local biodiversity is, and how warming oceans are affecting its condition and potential sustainability over time. This Thesis addresses these questions in three separate chapters. Chapter 2 presents a broad literature review about the influence of macroalgal features on biodiversity of associated epifauna and infauna. Its main conclusions are that physical characteristics of both individual and habitat macroalgal beds typically relate and, in some cases, explain an increase in the associated biodiversity. Chapter 3 presents the results of using a field survey to assess the hypothesis that structurally complex habitats support more diverse and abundant invertebrate communities than less complex habitats. This field study was complemented with an experimental comparison between live and artificial mimics of giant Irish moss and blue mussels, and the measurement of invertebrate colonization rates. The main results of Chapter 3 suggest that the most complex habitats (the combination of giant Irish moss and mussels) host larger, more abundant and diverse invertebrate communities. Additionally, living clumps of each habitat also support more diverse and distinct communities than their corresponding
mimics. Chapter 4 focuses on the condition of the giant Irish moss remnants by presenting the results of two types of laboratory experiments at different water temperatures. These experiments measured change in giant Irish moss weight and surface area in response to an array of consistent temperatures, as well as in response to temperature spikes, which are often recorded in Basin Head. Both experiments suggest that even though the giant Irish moss can adjust and is resilient to temperatures up to 28°C, temperatures above that cause a significant decline in its condition. Since most climate forecasts suggest an increase in ocean temperature in the future, this is concerning for the sustainability of this strain of Irish moss and the role it plays in the Basin Head ecosystem. Further efforts to study and restore the giant Irish moss are therefore essential to mitigate potential losses and ensure its sustainability
A review of Znln 2 S 4 ‐based photocatalysts for producing hydrogen by water splitting under visible light: Fundamentals and recent advancements
No full textHydrogen (H 2 ) is a clean energy carrier widely used in oil refineries, fertilizers, chemicals, and steel manufacturing. Presently, the majority of H 2 is produced from either steam methane reforming of natural gas or coal gasification; however, these technologies result in a massive amount of CO 2 emission. Alternatively, the use of photocatalysts for producing H 2 via water splitting is an eco‐friendly and sustainable approach, among which the selection of highly efficient, stable, and cheap photocatalysts is the key. In this review, Znln 2 S 4 ‐based photocatalysts are thoroughly described in terms of the fundamentals and thermodynamics of water splitting, fabrication methods, and different heterostructure photocatalytic systems. After this, recent developments in the large‐scale implementation of photocatalytic reactors are discussed. Finally, a summary of future research directions and major conclusions is provided. With proper modification, such as heterojunction systems and the selection of proper fabrication methods, Znln 2 S 4 ‐based photocatalysts could be superior materials for water splitting. In short, this review article could offer meaningful and useful insights and guidance for the development of Znln 2 S 4 ‐based photocatalysts in water splitting for producing H 2 under visible light
Exploring the predictive power of jejunal microbiome composition in clinical and subclinical necrotic enteritis caused by Clostridium perfringens: insights from a broiler chicken model
No full textBackground: Necrotic enteritis (NE) is a severe intestinal infection that affects both humans and poultry. It is caused by the bacterium Clostridium perfringens (CP), but the precise mechanisms underlying the disease pathogenesis remain elusive. This study aims to develop an NE broiler chicken model, explore the impact of the microbiome on NE pathogenesis, and study the virulence of CP isolates with different toxin gene combinations.
Methods: This study established an animal disease model for NE in broiler chickens. The methodology encompassed inducing abrupt protein changes and immunosuppression in the first experiment, and in the second, challenging chickens with CP isolates containing various toxin genes. NE was evaluated through gross and histopathological scoring of the jejunum. Subsequently, jejunal contents were collected from these birds for microbiome analysis via 16S rRNA amplicon sequencing, followed by sequence analysis to investigate microbial diversity and abundance, employing different bioinformatic approaches.
Results: Our findings reveal that CP infection, combined with an abrupt increase in dietary protein concentration and/or infection with the immunosuppressive variant infectious bursal disease virus (vIBDV), predisposed birds to NE development. We observed a significant decrease (p < 0.0001) in the abundance of Lactobacillus and Romboutsia genera in the jejunum, accompanied by a notable increase (p < 0.0001) in Clostridium and Escherichia. Jejunal microbial dysbiosis and severe NE lesions were particularly evident in birds infected with CP isolates containing cpa, netB, tpeL, and cpb2 toxin genes, compared to CP isolates with other toxin gene combinations. Notably, birds that did not develop clinical or subclinical NE following CP infection exhibited a significantly higher (p < 0.0001) level of Romboutsia. These findings shed light on the complex interplay between CP infection, the gut microbiome, and NE pathogenesis in broiler chickens.
Conclusion: Our study establishes that dysbiosis within the jejunal microbiome serves as a reliable biomarker for detecting subclinical and clinical NE in broiler chicken models. Additionally, we identify the potential of the genera Romboutsia and Lactobacillus as promising candidates for probiotic development, offering effective alternatives to antibiotics in NE prevention and control.Chicken Farmers of Saskatchewan and Poultry ScienceCluster II
Power perception and critical thinking promotion of clinical nursing instructors
No full textCritical thinking is viewed as necessary for the provision of safe, competent nursing care, and is vital to the use of evidence-based interventions and accurate nursing judgments. Therefore, nurse educators must assist in developing nursing students’ skills in critical thinking. Clinical experiences are a perfect time to do this as research demonstrates that presenting students with clinical cases or experiences in clinical practice are key to development of this skill. Research has shown that there are gaps in clinical nursing instructors’ comfort and training in promoting critical thinking in nursing students. Guided by Barrett’s Power as Knowing Participation in Change theory and Kolb’s Experiential Learning Theory, this quantitative research project was developed using intentional support and facilitated group discussion. The research question that guided this study: What is the effect of intentional support and facilitated
focus group discussion on clinical nursing instructors’ perception of power when teaching critical thinking to nursing students during clinical experiences? Data were collected using the Power as Knowing Participation in Change Tool developed by Elizabeth Barrett. Results showed a significant increase in the measurement of power before and after the intervention. This study supports the intervention showing that intentional support and group discussion are associated with an increase in the instructors’ perception of power to promote critical thinking during clinical experiences
Development of a patient specific 3D-printed drill guide for ventral slot surgery in dogs
No full textComplications associated with ventral slot decompression for cervical intervertebral disc extrusion have been reported in 9.9% of cases and include vertebral subluxation, hemorrhage, and neurologic deterioration. To minimize the risk of complications, slot dimensions should not exceed 33% of the length or width of the vertebral body. Achieving these dimensions intraoperatively may be challenging, thus use of a surgical guide may result in more accurate outcomes. The objective of this study was to compare accuracy and precision of ventral slot dimensions created using a 3D-printed patient-specific surgical guide or the conventional freehand technique in canine cadavers. CT data was used to create patient-specific surgical guides from 8 large breed canine cadavers. Intervertebral sites were randomized to undergo either a guided (n=12) or freehand (n=12) ventral slot by a novice surgery resident. Postoperative CT images were used to compare ventral slot dimensions, shape, and position. There was a significant difference between the intended and postoperative slot lengths of the freehand slots (p<0.01). Dimensions of the guided ventral slots were not statistically different from the planned dimensions. Use of the guides resulted in improved precision for ventral slot positioning relative to midline, divergence from midline, and slot shape (difference in coefficient of variations, 32%, 4%, and 40% respectively). This study confirms that the use of a 3D-printed patient specific surgical guide improves accuracy of ventral slot creation in canine cadavers and improves surgical precision when used by a single novice surgical resident. Future studies investigating the benefit of these guides when used by experienced surgeons and in live patients are warranted
Wildlife parasitology: sample collection and processing, diagnostic constraints, and methodological challenges in terrestrial carnivores
No full textWild terrestrial carnivores play a crucial role as reservoir, maintenance, and spillover hosts for a wide parasite variety. They may harbor, shed, and transmit zoonotic parasites and parasites of veterinary importance for domestic hosts. Although wild carnivores are globally distributed and comprise many different species, some living in close proximity to human settlements, only a few studies have investigated parasites of wild terrestrial carnivores using non-specific techniques. Access to samples of wild carnivores may be challenging as some species are protected, and others are secretive, possibly explaining the data paucity. Considering the importance of wild carnivores’ health and ecological role, combined with the lack of specific diagnostic methodologies, this review aims to offer an overview of the diagnostic methods for parasite investigation in wild terrestrial carnivores, providing the precise techniques for collection and analysis of fecal, blood, and tissue samples, the environmental impact on said samples, and the limitations researchers currently face in analyzing samples of wild terrestrial carnivores. In addition, this paper offers some crucial information on how different environmental factors affect parasite detection postmortem and how insects can be used to estimate the time of death with a specific highlight on insect larvae. The paper contains a literature review of available procedures and emphasizes the need for diagnostic method standardization in wild terrestrial carnivores
Prostaglandin E2 mediated inflammation and hypoxia in feline oral squamous cell carcinoma
No full textOral squamous cell carcinoma (OSCC) is the most common tumour of the feline oral cavity and is associated with devastating outcomes. Similar to human OSCC, Cyclooxygenase 2 (COX-2) expression and prostaglandin E2 (PGE2) synthesis have been demonstrated in feline OSCC (FOSCC). CD147, a known mediator of invasive behaviour, was also shown to be expressed in FOSCC. Other elements of the arachidonic acid pathway of inflammation, including microsomal and cytosolic PGE2 synthase enzymes (mPGES1, mPGES2 and cPGES) and PGE2 receptors (EP1-EP4), have not been investigated in FOSCC. Tumour hypoxia can support growing tumours by stimulating formation of new blood vessels through activity of hypoxia inducible factor 1 alpha (HIF-1α) and expression of vascular and endothelial growth factor type A (VEGFA). In humans, hypoxia impacts radiotherapy treatment and decreases the sensitivity of OSCC to chemotherapy. In human OSCC, expression of p16 is associated with papillomavirus infection and better prognosis. There have been fewer studies of p16 in FOSCC, and none directly comparing p16 expression in FOSCC to human OSCC. The objectives of this research were to investigate gene expression related to PGE2-associated inflammation and angiogenesis in vitro, to explore the relationship between mPGES1 and p16, COX-2, and CD147 in human and feline OSCC tumour samples, and to evaluate the effect of hypoxia on gene expression and cell culture viability resulting from chemotherapy and anti-inflammatory drug treatment. This work demonstrated that FOSCC cell lines express mPGES/cPGES genes (PTGES1-3) and EP receptor genes (PTGER1-4) to varying degrees, as well as genes encoding HIF-1α and VEGFA. Gene expression in FOSCC cells (SCCF2) was altered by exogenous PGE2 exposure, and EP4 antagonism resulted in varying responses suggesting that EP4 deserves further study in FOSCC. In biopsy samples of human and feline OSCC, immunohistochemistry (IHC) revealed that a subset of tumours expressed mPGES1 and p16. High CD147 expression was more common in high mPGES1 tumours in both species, though only reached statistical significance in the human samples. High p16 tumours were more common in the human oropharynx compared to the oral cavity, as expected given the importance of papillomavirus infection in the pathogenesis of human OSCC at this location. No significant difference in p16 expression between tongue and non-tongue tumours was observed in FOSCC. In vitro, 4 hours of hypoxia stimulated expression of PTGES1 (mPGES1). Interestingly, hypoxia reduced the sensitivity of SCCF2 to cytotoxic drugs (doxorubicin and carboplatin) but not to a cyclooxygenase inhibitor (piroxicam) or an EP4 inhibitor. Interestingly, hypoxia increased the antiproliferative effect of an mPGES1 inhibitor in SCCF2 cells. Collectively, these studies indicate mPGES1 may be an important mediator of inflammation and hypoxic response in FOSCC patients, possibly serving as a therapeutic target and deserving of continued study. Further study is needed in order to determine the role of p16 as a prognostic indicator in FOSCC. Based on p16 expression, it appears that FOSCC may have similarities with non-HPV-associated OSCC in people, which is more often localized to the oral cavity than the oropharynx and has a worse prognosis than HPV-associated tumours. New knowledge related to FOSCC mechanisms and treatment could benefit studies of oral cavity OSCC in people
Genome sequence comparisons between small and large colony phenotypes of equine clinical isolates of Arcanobacterium hippocoleae
No full textArcanobacterium hippocoleae is a Gram-positive fastidious bacterium and is occasionally isolated from the reproductive tract of apparently healthy mares (Equus caballus) or from mares with reproductive tract abnormalities. Apart from a few 16S rRNA gene-based GenBank sequences and one recent report on complete genome assembly, detailed genomic sequence and clinical experimental data are not available on the bacterium. Recently, we observed an unusual increase in the detection of the organism from samples associated with mare reproductive failures in Atlantic Canada. Two colony morphotypes (i.e., small, and large) were detected in culture media, which were identified as A. hippocoleae by MALDI-TOF mass spectrometry and 16S rRNA gene sequencing. Here, we report the whole genome sequencing and characterization of the morphotype variants. The genome length of the large phenotypes was between 2.42 and 2.43, and the small phenotype was 1.99 Mbs. The orthologous nucleotide identity between the large colony phenotypes was ~99%, and the large and small colony phenotypes was between 77.86 and 78.52%, which may warrant the classification of the two morphotypes into different species. Phylogenetic analysis based on 16S rRNA genes or concatenated housekeeping genes grouped the small and large colony variants into two different genotypic clusters. The UvrA protein, which is part of the nucleotide excision repair (NER) system, and 3-isopropoylmalate dehydratase small subunit protein expressed by the leuD gene were identified as potential virulence factors in the large and small colony morphotypes, respectively. However, detailed functional studies will be required to determine the exact roles of these and other identified hypothetical proteins in the cellular metabolism and potential pathogenicity of A. hippocoleae in mares