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Identification and Quantification of Sperm Head Plasma Membrane Proteins Associated with Male Fertility
Get PDFThe major objective was to characterize proteins in head plasma membrane (HPM) of sperm from animals of two species to identify species’ and proteins’ differences related to fertility. HPM’s sodium/potassium-ATPase (Na+⁄K+-ATPase) acts as a receptor, inducing capacitation when bound by its hormone ouabain. Na+/K+-ATPase is an α/β dimer, each with several isoforms (α1, α2, α3, α4, β1, β2, β3) whose exact relationship to in vivo fertility and capacitation is unknown. In the first study, specific Na+/K+-ATPase isoforms in sperm HPM of boars with different Direct Boar Effects (DBEs) for farrowing rate (FR) and litter size, differed between low and high fertility boars (LF, HF, n=6/each; DBE-based). SDS-PAGE and immunoblotting detected more α3 (P or <100; Semex evaluated). Statistical analysis identified 67 differential abundance proteins (DAPs) between HF and LF (n=3/group; P<0.05), which associated by meta-analysis to BFI. Gene ontology assigned 48 up-regulated HF proteins to sperm fertilization, and 19 down-regulated to catalytic and transporter activity. 38-up-regulated DAPs (HF and LF, n=16) correlated positively (r2=0.29 to 0.66; P≤0.05) and 6 down-regulated negatively (r2=0.26 to 0.44; P≤0.05) to BFI. The third study characterized HPM Na+/K+-ATPase in 16 bulls with differing BFI but similar sperm motility kinetics. Normalized Spectral Abundance Factor (NSAF) of α1 was significantly greater in 8 higher- vs 8 lower-fertility bulls. Linear regression positively correlated BFI to NSAF of α1 and β2 (r2=0.42 and 0.47, respectively; P≤0.05), and negatively correlated BFI to α4 (r2=0.37; P≤0.05), confirmed by bioinformatics predictions. These results suggest involvement of α1 and β2 in fertilization as potential fertility biomarkers. Overall, specific Na+/K+-ATPase isoforms identified in boar and bull sperm HPM significantly correlate with in vivo fertility, as do other specific bull HPM proteins. Elucidating potential fertility biomarkers in two species improves understanding of key proteins and their roles in various, complex mechanisms that enable successful sperm fertilization
ICEBEAR-3D: An Advanced Low Elevation Angle Auroral E region Imaging Radar
Get PDFThe Ionospheric Continuous-wave E region Bistatic Experimental Auroral Radar (ICEBEAR) is an auroral E~region radar which has operated from 7 December 2017 until the September 2019. During the first two years of operation, ICEBEAR was only capable of spatially locating E~region scatter and meteor trail targets in range and azimuth. Elevation angles were not determinable due to its East-West uniform linear receiving antenna array. Measuring elevation angles of targets when viewing from low elevation angles with radar interferometers has been a long standing problem. Past high latitude radars have attempted to obtain elevation angles of E~region targets using North-South baselines, but have always resulted in erroneous elevation angles being measured in the low elevation regime (0° to ≈30° above the horizon), leaving interesting scientific questions about scatter altitudes in the auroral E~region unanswered. The work entailed in this thesis encompasses the design of the ICEBEAR-3D system for the acquisition of these important elevation angles.
The receiver antenna array was redesigned using a custom phase error minimization and stochastic antenna location perturbation technique, which produces phase tolerant receiver antenna arrays. The resulting 45-baseline sparse non-uniform coplanar T-shaped array was designed for aperture synthesis radar imaging. Conventional aperture synthesis radar imaging techniques assume point-like incoherent targets and image using a Cartesian basis over a narrow field of view. These methods are incompatible with horizon pointing E~region radars such as ICEBEAR. Instead, radar targets were imaged using the Suppressed Spherical Wave Harmonic Transform (Suppressed-SWHT) technique. This imaging method uses precalculated spherical harmonic coefficient matrices to transform the visibilities to brightness maps by direct matrix multiplication. The under sampled image domain artefacts (dirty beam) were suppressed by the products of differing harmonic order brightness maps. From the images, elevation and azimuth angles of arrival were obtained. Due to the excellent phase tolerance of ICEBEAR new light was shed on the long standing low elevation angle problem. This led to the development of the proper phase reference vertical interferometry geometry, which allowed horizon pointing radar interferometers to unambiguously measure elevation angles near the horizon. Ultimately resulting in accurate elevation angles from zenith to horizon
Characterization of the salivary microbiome in COVID-19 infection and development of a cpn60 classifier
Get PDFThe human microbiome is thought to play an important role in many diseases. Recently, many studies have been done on the human microbiome and COVID19, caused by SARS-CoV-2, however only a few have been focused on the salivary microbiome, or oral microbiome in general, even though several oral symptoms of COVID19 are widely reported. In this study, we explored whether there is a difference in the taxonomic composition of the salivary microbiomes of people who are SARS-CoV-2 positive and people who are SARS-CoV-2 negative. We collected saliva samples from 138 volunteers (78 SARS-CoV-2 negative and 60 positive) and identified the salivary microbiota by chaperonin-60 (cpn60) amplicon sequencing. Taxonomic identification of the resulting sequencing was done by alignment to our cpn60 reference database using wateredBLAST. We found that the SARS-CoV-2 positive groups and the SARS-CoV-2 negative groups are different in their salivary microbiome composition on a population scale, however, the two groups are not significantly different in species diversity. Hierarchical clustering resulted in the identification of six clusters. Clusters dominated by Porphyromonas sp. or Prevotella melaninogenica contained significantly more SARS-CoV-2 positive samples than negatives, while clusters dominated by Streptococcus sanguinis or Megasphaera micronuciformis contained more SARS-CoV-2 negative samples. The results of the salivary microbiome study offered an opportunity to explore use of a Naïve-Bayesian classifier an alternative method for identification of cpn60 sequences that would overcome some of the limitations of the wateredBLAST alignment method. We trained the RDP classifier on a curated set of cpn60 barcode sequences, and tested its performance on cpn60 data from three human microbiomes: saliva, vagina, and stool. We found that 62%, 74% and 69% of salivary, vaginal and stool sequence variants were classified to the species level with confidence score >0.8, respectively. These confidently classified sequences accounted for 79%, 86% and 92% of the salivary, vaginal and stool microbiomes, respectively. Identification with the classifier also took significantly less time than wateredBLAST alignment. The results of the studies described in this thesis provide a foundation for future studies aimed at understanding the relationship of oral microbiota to SARS-CoV-2 infection and demonstrate that use of a Naïve-Bayesian classifier is a robust method for taxonomic identification of cpn60 sequences generated in these studies and studies of other microbiomes
OPTIMAL OPERATION AND PLANNING OF MICROGRIDS CONSIDERING FREQUENCY STABILITY
Get PDFIn modern power systems, the traditional power plants consuming fossil fuels are gradually being replaced by renewable plants which bring about several challenges and issues for the safe operation of these systems. Higher penetration of renewable plants weakens the grid’s frequency control capability. The frequency of a power system is an important indicator of any load-generation imbalance. If proper measures are not taken, the frequency-related events as a result of the contingencies might have devastating consequences such as unintentional load shedding, generator tripping, equipment damage, and blackout. The consequences have significantly higher impacts in a small-scale power system such as a microgrid where the penetration level of renewable generation is high, the inertia of the system is low, and the resources capable of providing reserve are limited. Battery energy storage systems (BESSs) have suitable characteristics to provide a wide range of high-power and high-energy services and they can have a significant contribution to frequency control if they are optimally scheduled. In a microgrid setting, the main goal of the frequency stability constraints is to prevent such consequences after the occurrence of credible contingencies and ensure the microgrid can ride through these events.
This thesis presents optimization models to take frequency stability constraints into account for microgrid operation and planning studies. In the operation stage, frequency stability constraints are integrated into the day-ahead scheduling model of a grid-connected microgrid considering the unit commitment constraints and the sudden islanding as the contingency. The goal of the proposed algorithm is to ensure that when a grid-connected microgrid suddenly and unintentionally disconnects from the main grid, the microgrid’s frequency stability metrics remain within their safe ranges and the resources can provide sufficient primary frequency response to this end.
Also, for the planning stage, optimal sizing of a BESS as a source of power and energy services is studied considering the frequency stability constraints for grid-connected and islanded microgrids. For realistic modeling, a detailed frequency response model of the microgrid elements under different contingency types is developed based on a discretized model of the swing equation. The developed optimization models are linear and relatively fast in obtaining the globally optimum solution with the proposed reformulated mathematical models. A k-means clustering algorithm is also used for scenario reduction purposes and identification of representative days.
For all the studies, a microgrid test case comprised of conventional generators, a PV plant, BESS, and loads is used. The discretized swing equation and time-domain model of the primary frequency response of microgrid units are used without sacrificing accuracy. Also, the accelerated decomposition techniques ensure the computational burdens are reasonable and they improve the performance of the algorithms. All the simulations and codings were done in the GAMS and MATLAB environments
Performance of alumina supported Ni catalyst with core-shell and supported structures in dry reforming of methane
Get PDFDry reforming of methane is one the interesting processes in which CH4 and CO2 are consumed at the same time and valuable syngas is produced. In this research, Ni@Al2O3 core shell structure catalyst is compared with the Ni/Al2O3 supported catalysts in terms of their catalytic stability, activity and carbon formation in dry reforming of methane. The core-shell structure catalysts were prepared by microemulsion method and impregnation technique was used for the supported catalysts. The Ni loadings were 5- 20 wt. % for the both types of catalysts. The prepared catalysts were analyzed with BET, XRD, TPR, XPS, TEM, XAS, and ICP analysis. BET analyses, TEM, and SEM-EDS images showed that core- shell structure catalysts were successfully prepared with smaller particle size and higher surface area (≥ 200 m2/ g) than the supported catalysts ( ˂ 200 m2/ g). Furthermore, TPR and XPS analysis revealed that NiAl2O4 species was the main Ni phase in all the catalysts, making strong interaction between Ni and Al2O3. XANES analysis revealed that all the catalysts were almost reduced completely. The catalytic test reaction was carried out at 750 ºC, GHSV= 144 L. g-1 .h-1 and CH4:CO2: N2= 1:1:1. The results demonstrated that core- shell catalysts had better catalytic activity than the supported catalysts due to encapsulation of Ni with shell, preventing Ni particle from agglomeration and sintering in comparison with the supported catalysts. The highest CH4 and CO2 conversions belonged to 20%Ni@Al2O3 catalyst with around 55% and 57%, respectively. Further, H2/CO ratio was almost 1 for the core-shell catalyst whereas this amount was around 0.9 for the supported catalysts. The lower amount of carbon was also deposited in the core- shell catalysts due to smaller particle size and Ni covered with the shell. The lowest amount (~2wt.%) of coke deposited on the 12% Ni@Al2O3 catalysts while this amount was about 5 wt. % for the supported catalysts with the same loading. The long term thermal stability test (24 h) showed great stability for the core-shell structure catalyst while it was gradually deactivated after 120 h in reaction due to carbon formation
THREE ESSAYS ON THE ECONOMICS OF SMALLHOLDER AGRICULTURE IN AFRICA: LABOUR ALLOCATION, ADOPTION OF CONSERVATION AGRICULTURE AND CO-OPERATIVE PARTICIPATION
Get PDFSmallholder farmers dominate agricultural production in many developing countries and produce a significant portion of the food that is consumed within those countries. Given their important contribution, there is strong consensus that improving productivity among smallholder farmers is one of the most effective ways of ensuring food security and alleviating poverty in developing countries. However, the means by which agricultural performance could be enhanced is not straight forward because smallholder farmers operate under complex environments and face multifaceted challenges, including declining soil fertility, the use of poor farming techniques, limited use of fertilizers, low technology adoption, gender disparities, and market failures.
This study contributes to improving our understanding of smallholder farmers by examining three of these challenges: labour allocation, technology adoption, and market selection. The specific goals of this study are to: (1) assess the influence of social norms on farm labour allocation and productivity; and (2) examine the factors influencing CA adoption, paying attention to the role of social norms; and (3) examine the impact of agricultural co-operatives on smallholder farmers.
To achieve the first objective, the study develops a theoretical framework that incorporates the role of social norms in labour allocation. The study then empirically examines how social norms influence labour allocation and productivity through the estimation of a time allocation model and a production function model in which male and female labour are differentiated. To achieve the second objective, the study estimates a probit model to examine how social norms affect CA adoption. To attain the third objective, the study develops a theoretical model showing how a co-operative affects smallholder farmers in a modern agri-food supply chain.
With respect to labour allocation, the results show that women and men do different farm tasks, with men showing a preference in doing activities that use mechanical farm implements, such as controlling ox-drawn ploughs, while women assume manual tasks such as weeding or fertilizer application. Overall, women work more than men, particularly when they are under a female-headed household. These results suggest that social norms are at play.
Regarding the adoption of CA, the results show that farmers differentially adopt the three CA components. While most farmers adopted minimum disturbance, only a few adopted mulching. The results also show that farmers who consider social advice and require peer support to try new technologies are less likely to practice mulching. This suggest that mulching does not align with the local norms and values.
The results of the theoretical modeling of agricultural co-ops show that they can play an important role in serving smallholder farmers who would otherwise be excluded from the market. The existence of a co-op forces IOFs to pay higher prices than they otherwise would.
One of the findings of the thesis is that social norms are important in determining the future of smallholder agriculture in Africa. Altering social norms could result in a more efficient allocation of resources and improved adoption of technologies. However, given that social norms are difficult to change, it is important to develop interventions that align with the existing norms. One way of achieving this is to involve farmers when developing interventions to ensure that local norms and values are incorporated. For instance, to improve men’s participation, it is likely important to develop and promote technologies that rely on mechanized farm implements given that such technologies are attractive to men
Electrocatalytic Oxidation of Nitrophenols via Ag Nanoparticles Supported on Citric-Acid-Modified Polyaniline
Get PDF© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).Government of Canada through the Natural Sciences and Engineering Research Council of Canada as a Discovery Grant (RGPIN 04315-2021) awarded to LDW. MK acknowledges the partial support provided by the University of Saskatchewan through the award of a Graduate Teaching Fellowship (GTF).Peer ReviewedCitric-acid-modified polyaniline (P-CA) and P-CA modified with Ag nanoparticles (Ag@PCA) were prepared via an in situ reduction method. The physicochemical properties of P-CA and Ag@P-CA were compared to unmodified polyaniline (PANI) and PANI-modified Ag nanoparticles (Ag@PANI). Ag@P-CA had a lower content of aniline oligomers compared to Ag@PANI. P-CA and Ag@P-CA had a greater monolayer adsorption capacity for 2-nitrophenol and lower binding affinity as compared to PANI and Ag@PANI materials. X-ray photoelectron spectroscopy and cyclic voltammetry characterization provided reason and evidence for the higher conductivity of citric-acid-modified materials (P-CA and Ag@P-CA versus PANI and Ag@PANI). These results showed the potential utility for the optimization of adsorption/desorption and electron transfer steps during the electrochemical oxidation of nitrophenols. The oxidation process employs Ag@P-CA as the electrocatalyst by modifying polyaniline with Ag nanoparticles and citric acid, which was successfully employed to oxidize 2-nitrophenol and 4-nitrophenol with comparable selectivity and sensitivity to their relative concentrations. This work is envisaged to contribute significantly to the selective conversion of nitrophenols and electrocatalytic remediation of such waterborne contaminants
THRIVANCE DURING THE PANDEMIC: URBAN INDIGENOUS WOMEN AND MENTAL WELLNESS
No full textPrior to colonization, Indigenous people were healthy and thriving. As a result of colonization and its ongoing ramifications, Indigenous peoples’ health has deteriorated over the last 600 years, spanning multiple generations. Despite the troubling statistics, Indigenous people are thriving. This project sought to highlight Indigenous women’s stories of thrivance during the pandemic and through events of historical loss and asked the question, how are Indigenous women coping and thriving with mental wellness during the COVID-19 pandemic? Using a survey methodology and the Indigenist Stress Coping Model (ISCM), the following findings emerged: (a) Indigenous women thrive in the company of Indigenous women, (b) Indigenous women thriving involves healing and (re)connection, (c) Land has helped women cope and thrive during the pandemic, and (d) Availability of access to services, the healing relationship with a health care provider, and culturally appropriate care both facilitators and barriers to one’s ability and desire to access mental health services
ʔeɬa ʔeghádalaída
No full textStatement about ethical and culturally sensitive research practices developed at meeting of Indigenous partners in Global Water Futures research projects.Canada First Research Excellence FundNon-Peer ReviewedResearchers working in Indigenous communities should follow ethical and culturally sensitive research practices, based on the following principles: Wellness of community is a primary
objective; Observe and abide by local protocols; Equity is needed in supporting and funding
knowledge; Intellectual property will remain with communities who will determine what can be shared
WHOLE-BODY UREA KINETICS AND FUNCTIONAL ROLES OF UREA TRANSPORTERS AND AQUAPORINS IN UREA SECRETION INTO THE RUMEN IN SHEEP FED DIETS VARYING IN CRUDE PROTEIN CONTENT AND CORN GRAIN PROCESSING METHOD
No full textThe objectives were to determine the effects of dietary crude protein (CP) content and corn grain processing on serosal-to-mucosal urea flux (Jsm-urea) in ruminal epithelia. Thirty-two Rideau-Arcott lambs were blocked by BW into groups of 4 (i.e., a total of eight blocks) and then randomly allocated within block to 1 of 4 dietary treatments (n = 8) in a 2 × 2 factorial design. Dietary factors were CP content (11% [LP] vs. 16% [HP]) and method of corn grain processing (whole-shelled [WSC] vs. steam-flaked [SFC] corn). Four blocks of animals (n = 4) were used in 4-day continuous infusions of [15N-15N]-urea with concurrent collections of urine and feces to determine whole-body urea kinetics and nitrogen (N) balance. After 23 days of dietary exposure, lambs were killed to collect ruminal epithelia which were mounted in Ussing chambers to determine Jsm-urea. Lambs fed HP had greater N intakes (29.4 vs. 19.1 g/d; P < 0.01) and total N excretion (20.3 vs. 14.5 g/d; P < 0.01) than those fed LP. Endogenous urea-N production (UER) was greater in lambs fed HP compared to those fed LP (29.9 vs. 20.6 g/d; P = 0.02), whereas urea-N secreted into the gut (GER; g/d) and urea-N used for anabolic purposes (UUA; g/d) were similar. Lambs fed LP tended to have greater GER:UER (0.78 vs. 0.66; P = 0.05) and UUA:GER (0.23 vs. 0.13; P = 0.05) ratios, and Jsm-urea (144.7 vs. 116.1 nmol/[cm2 × h]; P = 0.07) compared to those fed HP. Lambs fed SFC had a lower phloretin-insensitive Jsm-urea (87.1 vs. 143.1 nmol/[cm2 × h]; P = 0.02) and tended to have a lower NiCl2-insensitive Jsm-urea (117.4 vs. 178.4 nmol/[cm2 × h]; P = 0.09) compared to those fed WSC, whereas total Jsm-urea and total-insensitive Jsm-urea were similar. Lambs fed SFC tended to have a lower mRNA expression of UT-B (0.89 vs. 1.07; P = 0.08) and AQP-3 (0.90 vs. 1.05; P = 0.07) compared to those fed WSC. These results suggest that urea transport through UT- and AQP-mediated pathways can be upregulated in ruminants by feeding more ruminally-fermentable carbohydrates (manipulated via grain processing)