Understanding the population genetic structure of bovine mastitis-causing Staphylococcus aureus in New Zealand to identify potential vaccine candidates using reverse vaccinology : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Palmerston North, New Zealand

Listed in 2022 Dean's List of Exceptional ThesesStaphylococcus aureus is one of the major causes of bovine mastitis in New Zealand and worldwide, causing severe economic loss to the dairy industry. With significant advances in whole-genome sequencing (WGS) and associated bioinformatics, S. aureus from bovine mastitis has been studied worldwide, but the understanding of the organism's genomics is still incomplete. To my knowledge, there have been no published WGS studies of S. aureus in dairy cattle in New Zealand to date. As WGS has become more affordable, and the concomitant bioinformatic analysis offers high-resolution indiscriminating betweenS. aureus lineages, WGS analysis was applied to a sample of S. aureus isolates obtained from dairy cattle in New Zealand. The work is undertaken in this thesis utilised advanced WGS analyses to study the genomic epidemiology ofS.aureusfrom dairy cattle over a period of 15 years. The findings from the analysis enabled a subsequent reverse vaccinology analysis that identified a number of conserved peptides potentially useful for incorporation in subunit vaccines for cattle. The first study analysed the population genetic structure of the pathogen using 188 bovineS. aureus isolates were collected from dairy farms across New Zealand in 2002-03, 2013-14, and 2017-18. Ruminant-specific and non-specific clonal complexes(CCs) were identified. CC1 was the dominant CC, a unique feature not observed in dairy cattle in other countries. CC1 was predominant in cattle in the three periods of isolate collection, suggesting a stable and successful clonal lineage. Interestingly, CC1is also the predominant CC in humans in New Zealand, and is mainly associated with humans in other countries and is not commonly reported in cattle. The second study compared the genomes of the bovineS. aureus isolates from the first study with genomes of quasi-contemporaneous human, canine and feline(n=59), and small ruminant (n=30) isolates also collected in New Zealand. Comparative genomic analyses of the core and accessory genomes were used to assess the effect of the host species of origin on the phylogenetic clustering of the isolates, and to identify host-specific/host-adaptive genomic signatures. Comparative analysis of CC1isolates identified marked phylogenetic segregations of both the core and accessory genomes among cattle and humans, and the presence of previously described ruminant-adaptive genes in bovine isolates, but not in human isolates. To my knowledge, this is the first report of ruminant host adaptation within CC1. The third study compared the antimicrobial resistance results obtained using the Disk Diffusion test (DD) with a resistome analysis, to assess the potential usefulness of WGS analysis to predict the antimicrobial resistance phenotype of bovineS. aureus. The antimicrobial resistance genes identified were: theβ-lactamase geneblaZ, the erythromycin resistance gene ermC, the streptomycin resistance gene str, and the fusidic acid resistance gene fusC. WGS identification of theblaZgene had a sensitivity of 71% and a specificity of 100% in predicting resistance when the DD test was considered the reference standard. Similar analyses could not be performed with other antimicrobials due to the low frequency of other resistance genes in the sample. Finally, the information obtained from the first two studies was used to construct a reverse vaccinology bioinformatic pipeline to identify potential vaccine candidate (PVC) proteins for S. aureus mastitis. Eighteen PVC proteins were identified using a range of bioinformatics tools. Some of these proteins have previously been shown to be immunogenic through in vitro and animal studies, providing cross-validation to the pipeline, while others have not yet been tested. In summary, this thesis presents a detailed description of the population genetic structure of bovine mastitis-causing S. aureus in New Zealand over 15 years. The work provides new insights into the complex mechanisms of S. aureus host-adaptation to ruminants and identifies some obstacles for the successful application of genomic analysis for the prediction of the antimicrobial resistance phenotype of clinical S. aureus isolates. Potentially useful proteins to be included in subunit vaccines for cattle are also reporte

Materials and Components for Low Temperature Solid Oxide Fuel Cells – an Overview

This article summarizes the recent advancements made in the area of materials and components for low temperature solid oxide fuel cells (LT-SOFCs). LT-SOFC is a new trend in SOFCtechnology since high temperature SOFC puts very high demands on the materials and too expensive to match marketability. The current status of the electrolyte and electrode materials used in SOFCs, their specific features and the need for utilizing them for LT-SOFC are presented precisely in this review article. The section on electrolytes gives an overview of zirconia, lanthanum gallate and ceria based materials. Also, this review article explains the application of different anode, cathode and interconnect materials used for SOFC systems. SOFC can result in better performance with the application of liquid fuels such methanol and ethanol. As a whole, this review article discusses the novel materials suitable for operation of SOFC systems especially for low temperature operation

Soft Chemical Fabrication and Material Characterization of Mn Doped SnO2 Ceramic Nanostructures for Application in Photocatalysis

In this research work, a simple soft chemical synthesis route is adopted to synthesize (Sn1-xMnxO2-δ; where x=0, 0.05,0.10, 0.15 and 0.20) based ceramic nanoparticles. The prepared nanoparticles were characterized to X-ray diffraction(XRD), FTIR spectroscopy, particle size analysis, SEM, EDAX, UV and photoluminescence (PL) studies. From XRD, thecrystalline geometry of ceramic nanoparticles was found to be tetragonal. FTIR data have shown a broad absorption band ata wavelength of ~ 600 cm-1 due to M-O stretching vibration mode. The ceramic nanoparticles were found to be in the rangeof 704 to 1258 nm. Smaller grains (<100 nm) along-with few bulky grains were reported by SEM. The absorption ofceramic particles was found maximum at 283 nm as per UV spectra. PL spectra exhibited a strong peak at 432 nm. Thephotocatalysis was studied to degrade methylene blue dye present in water sample using the ceramic nanoparticles underUV, visible and sun lights. Among the samples studied, Sn0.95Mn0.05O2-δ exhibited better photocatalytic degradation behavior(84.8%) under visible light after 120 minutes of irradiation

Combustion synthesis and characterization of Ni-doped LiMn2O4 cathode nanoparticles for lithium ion battery applications

In this research work, fine powders of spinel-type LiMn2-xNixO4-δ (where x = 0.1, 0.2, 0.3, 0.4 and 0.5) as cathode materials for lithium ion batteries were synthesized by combustion synthesis using urea as fuel and metal nitrates as oxidizers at a temperature of 600°C. The physiochemical properties of the prepared cathode materials were investigated by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), particle size analysis, energy dispersive analysis (EDAX) and scanning electron microscopy (SEM). The electrochemical characteristics were studied by impedance spectroscopy. It was found that the physical charactetertistics were moderately influenced because of different dopant (Ni) concentration. Among the samples studied,  LiMn1.9Ni0.1O4-δ resulted in better electrical conductivity (6.49 x 10-5 Scm-1) at room temperature and hence it may be suitable for lithium ion battery applications.Keywords:Ni doped LiMn2O4,  physical characterization, lithium ion battery application

Photocatalytic, antibacterial and electrochemical properties of novel rare earth metal oxides-based nanohybrids

Mixed metal oxide nanocomposites (rare earth-based) have become irreplaceable and tend to display great functioning in all kinds of arenas like as photocatalytic, electrochemical, and biological. NiO-CGSO [NiO-Ce0.8Gd0.2O2-??Ce0.8Sm0.2O2-?] nanomaterial was produced by the wet-chemical route for numerous purposes. The development of (FCC) face-centered cubic structure confirmed and there was no derivative phase was observed by XRD. Metal-Oxygen bond was revealed by FTIR analysis. The morphology and elemental composition of the sample were carried out using SEM with EDAX. The optical bandgap of prepared nanocomposite was studied using UV?Vis spectroscopy. Electrochemical behaviour was observed at conditions, voltage (1.3 V), and the frequency (42 Hz?5 kHz). Photocatalytic and antibacterial behavior of prepared NiO-CGSO nanocomposites also investigated. It was found that this novel composite catalyst decomposed 92% of toxic pollutants from wastewater. Further, NiO-CGSO composites showed superior antibacterial performance against aeromonas hydrophila, E. coli, and S. epidermis bacterial pathogens.Scopu

Using e-learning to support international students' dissertation preparation

Purpose: A research paper on the design and implementation of an e-learning resource responding to the globalisation of education. The purpose of this paper is to focus on the challenges presented in learning and teaching on how to support international postgraduate (PG) students undertaking the specific task of a dissertation. Design/methodology/approach: Using findings from 250 PG students, 40 supervisors and two module tutors the research identified the content and language issues faced by students and recognised the need to design an enabler supporting the latter as independent learners and the academic staff delivering support. Findings: The e-learning tool provides an independent learning tool which addresses student concerns relating to the process and content of structuring a dissertation and the function of language. Initial responses have been positive from both staff and students in respect to providing a source of student support and feedback. Originality/value: The research shows how the Dissertation Game Model (DGM), evolved into an e-learning resource supporting student understanding of the content, structure, planning and writing of a dissertation. The e-learning tool focuses on helping international students understand what the generic contents of each chapter of a dissertation should contain and supports them in engaging in research as a transferable skill

INVESTIGATION OF THE THERMAL PERFORMANCE OF A SOLAR ASSISTED AIR CONDITIONER UNDER TROPICAL CLIMATE

Air conditioning is a process that includes heating, cooling, humidification, dehumidification, cleaning and circulation of air in an enclosed space. Air conditioners are the main equipment’s in a Heating, Ventilation and air conditioning (HVAC) system. In a tropical weather country like Malaysia, the demand for cooling of indoor air is growing due to increasing comfort expectations and cooling loads. Air conditioning have now become a necessity for providing indoor cooling in majority of buildings in Malaysia. These buildings use conventional cooling technologies which commonly uses lots of energy. Due to this, renewable energy sources have become a solution to help overcome this problem. Solar air-conditioning is one of the ways to reduce the demand for electricity. Conventional air conditioners consist of a compressor, a condenser, an expansion valve and an evaporator. Similar to this is also a solar air conditioner except for its additional part which is the solar collector. This solar collector acts as a heat absorber for the refrigerant passing through it. A conventional air conditioner consumes electricity but a solar air conditioner consumes partial electricity and partial solar energy. Therefore, the load on this solar air conditioner will be less than the conventional one. For this process, refrigerant 407 C is used because of its positive impact towards the environment. To assess the performance of these two types of air conditioners, the working principle and the difference in the refrigeration cycle is analysed. In order to measure the pressure and temperature of the refrigerant as well as the humidity, a software called iManifold is used to measure required parameters and sends the observation straight to a smart phone using the installed application. Specific iManifold probes are used to obtain readings from the air conditioner. This performance can then be transferred to the generation of P-V or T-S diagram. Based on the difference in power consumption, the mitigation of carbon dioxide gas can be evaluated. As for monitoring and measurement purposes, the difference in cooling performance of this air conditioner is compared to the outside air and taken to consideration

INVESTIGATION OF THE THERMAL PERFORMANCE OF A SOLAR ASSISTED AIR CONDITIONER UNDER TROPICAL CLIMATE

Air conditioning is a process that includes heating, cooling, humidification, dehumidification, cleaning and circulation of air in an enclosed space. Air conditioners are the main equipment’s in a Heating, Ventilation and air conditioning (HVAC) system. In a tropical weather country like Malaysia, the demand for cooling of indoor air is growing due to increasing comfort expectations and cooling loads. Air conditioning have now become a necessity for providing indoor cooling in majority of buildings in Malaysia. These buildings use conventional cooling technologies which commonly uses lots of energy. Due to this, renewable energy sources have become a solution to help overcome this problem. Solar air-conditioning is one of the ways to reduce the demand for electricity. Conventional air conditioners consist of a compressor, a condenser, an expansion valve and an evaporator. Similar to this is also a solar air conditioner except for its additional part which is the solar collector. This solar collector acts as a heat absorber for the refrigerant passing through it. A conventional air conditioner consumes electricity but a solar air conditioner consumes partial electricity and partial solar energy. Therefore, the load on this solar air conditioner will be less than the conventional one. For this process, refrigerant 407 C is used because of its positive impact towards the environment. To assess the performance of these two types of air conditioners, the working principle and the difference in the refrigeration cycle is analysed. In order to measure the pressure and temperature of the refrigerant as well as the humidity, a software called iManifold is used to measure required parameters and sends the observation straight to a smart phone using the installed application. Specific iManifold probes are used to obtain readings from the air conditioner. This performance can then be transferred to the generation of P-V or T-S diagram. Based on the difference in power consumption, the mitigation of carbon dioxide gas can be evaluated. As for monitoring and measurement purposes, the difference in cooling performance of this air conditioner is compared to the outside air and taken to consideration

Recent developments in solid oxide fuel cell technology – a review

169-176This review presents development of low temperature solid oxide fuel cells (SOFC), which with high efficiency and high environmental performance have shown excellent potential as a future source of energy for vehicles and homes. Gd2O3 and Sm2O3 doped ceria based nanomaterials were developed world wide, as alternate electrolyte materials for SOFCs working at reduced temperature (700°C) since, state-of- art YSZ based electrolytes undergo interfacial reactions with adjoining cell components at operating temperature of SOFC after prolonged operation. Novel ceramic composite materials are reported as alternate electrode components of reduced temperature SOFC. Iron based alloys are developed as current collectors for low temperature SOFC applications