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An Investigation into Speaker and Headphone-Based Immersive Audio for VR and Digital Gaming Applications

- Marais, Kyle Donald

Authors: Marais, Kyle Donald
Date: 2022-10-14
Subjects: Uncatalogued
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/365246 , vital:65720
Description: There is a need for audio spatialization in gaming and Virtual Reality applications. If the sounds of a virtual environment correspond to their visual sources, the user will feel more engrossed or immersed in the environment and will more likely suspend their disbelief. Certain software, such as Audio Middleware, works in cooperation with game engine software to facilitate the audio requirements for virtual environment and game developers. This thesis provides a comparison of speaker and headphone-based immersive audio systems in the context of Virtual Reality, with the aim of determining and analyzing the differences between both systems. Accordingly, the thesis describes the implementation of an enhanced speaker-based Audio Middleware sound capability for Unity game engine developers. The capability leverages the functionality of a popular Audio Middleware software suite, FMOD, and a speaker-based spatialization system, ImmerGo. The headphone spatialization system that was contrasted with the bespoke speaker-based system was the Oculus Audio Spatializer. A sample VR application that employs both spatialization systems was developed, and served as the testing framework for the experimentation. Ultimately, the application provides users with 3D sound control in real time. Thus, via the use of the Leap Motion controller and Oculus Rift Development Kit 2 Head-Mounted Display (HMD), users can select an audio source with a gesture, and then subsequently pan the audio around them in three-dimensional space. The findings of the research suggest that the speaker-based system facilitated greater immersion than the headphone-based system, despite the headphone-based system providing more accurate audio localization and a higher ‘perceived audio quality’. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
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Date Issued: 2022-10-14

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Bioactivity evaluation of manno-oligosaccharides produced from spent coffee grounds using a Bacillus sp. derived endo-1,4-β-mannanase

- Magengelele, Mihle

Authors: Magengelele, Mihle
Date: 2022-10-14
Subjects: Uncatalogued
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/365233 , vital:65719
Description: Coffee is one of the most popular beverages produced worldwide; however, its processing results in the generation of spent coffee grounds (SCGs). SCG as an agro-industrial waste which leads to adverse environmental effects, such as carbon dioxide and methane production, when disposed of in landfills. SCGs contain high levels of polysaccharides such as mannan, specifically galactomannan; thus, the utilisation of this waste is an important subject. Recently, there has been a growing interest in the production of nutraceutical mannooligosaccharides (MOS) through the enzymatic hydrolysis of mannans. MOS have been reported to exhibit various bioactive properties, including prebiotic effects, the ability to inhibit pathogens and antioxidant activity. In this study, a Bacillus sp. derived endo-1,4-β-mannanase, Man26A, was used for the production of MOS from model mannan substrates; ivory nut mannan (INM), locust bean gum (LBG) and guar gum (GG). After incubation, Man26A exhibited saccharification yields of 30.18, 36.86 and 34.93% for INM, LBG and GG, respectively. Kinetic studies showed that Man26A had a high binding affinity and catalytic efficiency for LBG (Km = 10.8 mg/mL and kcat/Km = 8.8 min-1 mg-1mL) than INM (Km = 28.9 mg/mL and kcat/Km = 3.8 min-1 mg-1mL) and GG (Km = 50.2 mg/mL and kcat/Km = 2.6 min-1 mg-1mL). The hydrolysis products from these model mannan substrates were quantitatively and qualitatively analysed using high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC), respectively. INM hydrolysis resulted in the production of mannose (M1) - mannotriose (M3), while LBG hydrolysis resulted in the generation of M1 - M2 (mannobiose) and mannopentaose (M5) - mannohexaose (M6) as the dominant sugars. On the other hand, GG hydrolysis mainly produced M5 - M6, and some oligosaccharides with a degree of polymerisation (DP > 6). Putative galactosyl-MOS; GM2 and GM3, were also observed in the HPLC chromatograms of both LBG and GG hydrolysates. The MOS produced from these model mannan substrates were stable over a broad pH range of 2 - 10. Furthermore, MOS produced by enzyme hydrolysis showed antioxidant properties, with MOS obtained from INM showing higher antioxidant activity than those from LBG and GG. A mannan-rich agro-processing waste, SCG, was pretreated using NaOH and hydrolysed using Man26A under the optimised conditions obtained from the model mannan hydrolysis studies for MOS generation. Structural analysis studies performed using Fourier-transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) confirmed the structure of untreated and pretreated SCGs, and some chemical differences were observed in the untreated and pretreated SCGs. TGA analysis specifically showed that pretreated SCG was more resistant to temperature induced decomposition than untreated SCG. The removal of lignin during the pretreatment of SCG was observed by TGA, whereas the decomposition of lignin was only observed in untreated SCG. Using FT-IR, α-linked D-galactopyranose units (812 cm-1) and β-linked D-mannopyranose units (817 cm-1) were observed in both untreated and pretreated SCGs, confirming the galactomannan presence. MOS were successfully produced from the hydrolysis of NaOH pretreated SCG by Man26A, where M2 (1.04 mg/mL) and M3 (1.20 mg/mL) were the main products. The effect of bile salts, α-amylase, trypsin and hydrochloric acid on SCG-MOS was investigated, and they did not degrade SCG-MOS. The effect of SCG MOS on the in vitro survival of beneficial bacteria was investigated. SCG-MOS enhanced the growth of Lactobacillus bulgaricus, Bacillus subtilis and Streptococcus thermophilus, and led to the production of short chain fatty acids (SCFAs). The growth of beneficial bacteria in the presence of SCG-MOS was 2-fold higher than in the presence of the glucose control and sugar-free control. Bacterial SCFAs production was more in carbon source containing broth than sugar-free broth. In terms of autoaggregation influence, L. bulgaricus, B. subtilis and S. thermophilus grown in the presence of SCG-MOS showed aggregation percentages of 18.21, 20.98 and 17.99%, respectively. The formation of biofilms by these bacterial cells in the presence of SCG-MOS were approximately 2-fold higher than the values obtained in the positive mannose control and sugar-free control. Utilisation of SCG-MOS activated putative mannan degrading genes in beneficial bacteria, resulting in the production of mannan degrading enzymes, such as β-mannanase, β-mannosidase and α-galactosidase. In conclusion, this study demonstrated that enzymatic hydrolysis of SCG using Man26A resulted in the production of M2 and M3 as the predominant MOS. These MOS have prebiotic effects, which may be essential for the improvement of animal and human health. The MOS possibly act in the digestive tracts of mammals by enhancing the production of beneficial secondary metabolites, such as SCFAs, and enhancing autoaggregation and biofilm formation of beneficial bacteria, which may likely lead to competitive exclusion of pathogenic bacteria in the host’s digestive tract. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
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Date Issued: 2022-10-14

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Development of biosensor systems for the detection of anti-cancer drugs and prostate cancer

- Mwanza, Daniel

Authors: Mwanza, Daniel
Date: 2022-10-14
Subjects: Uncatalogued
Language: English
Type: Academic theses , Doctoral theses , text
Identifier: http://hdl.handle.net/10962/365929 , vital:65803 , DOI 10.21504/10962/365929
Description: Rapid, low-cost and accurate point-of-care analytical devices are highly required for the detection of cancer biomarkers for the early diagnosis and determination of anti-cancer drugs for monitoring of cancer-related diseases. This thesis focused on the development of biosensor systems for the detection of anti-cancer drug, methotrexate (MTX) and prostate cancer biomarker, prostate-specific antigen (PSA). Ultrasensitive electrochemical immunosensors were fabricated by covalent immobilization of polyclonal anti-MTX and monoclonal anti-PSA antibodies onto glassy carbon, screen-printed carbon and gold electrodes which were pre-modified with isophthalic acid (IPA) thin monolayer film. A methodology based on the steric hindrance by 1,3-substituted aryldiazonium salt was adopted to enable the electrografting of IPA thin monolayer film on electrode surfaces. The antibodies were immobilized onto the IPA thin monolayer film via carbodiimide chemistry to form a sensing or analyte capture surface. For the detection of MTX, the analytical performance of the non-Faradaic electrochemical impedance spectroscopy (EIS) immunosensor was validated using singular value decomposition (SVD). The non-Faradaic EIS detection of PSA was validated using Nyquist plots of total capacitance, complex capacitance calculated from the imaginary part of impedance, and the capacitance acquired from the circuit fitting. The detection of PSA was further studied using colorimetric sensing platform which was developed by forming a sandwich immunoassay. For the immunoassay detection, the anti-PSA captured monoclonal antibodies were immobilized onto the microwell plates. The sensing signal was obtained from bioconjugating the anti-PSA antibody polyclonal onto glucose-encapsulating nanoliposomes (GENLs-anti-PSA-pAb). The preparation of glucose -encapsulated nanoliposomes were evaluated for their potential to release glucose in a controlled manner using Triton-X 100 or acidic phosphate buffer saline (PBS, pH 5.0). The detection of PSA (in a sandwich manner) was correlated to the concentration of glucose quantified using horseradish peroxidase (HRP), Pd|PdO nanoparticles, and personal glucose meter. The immunosensors developed in this work exhibited high stability, selectivity, low detection limits, and a wide linear range which was suitable for screening of both PSA and MTX. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
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Date Issued: 2022-10-14

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Exploring integration for the topic of stoichiometry in South African natural sciences and physical sciences school curricula

- Mgolozeli, Kwanele

Authors: Mgolozeli, Kwanele
Date: 2022-10-14
Subjects: Uncatalogued
Language: English
Type: Academic theses , Master's theses , text
Identifier: http://hdl.handle.net/10962/405330 , vital:70162
Description: Many developing countries, including South Africa, have identified the provision and implementation of strong science curricula as central to their developmental needs. Stoichiometry is a fundamental chemistry topic because the concepts involved form the basis of later topics such as chemical equilibrium, rates of reactions, redox reactions, and acid-base reactions. School students consistently demonstrate lack of understanding of stoichiometry-related concepts and skills such as the particulate nature of matter and related mathematical problem-solving. The poor performance of high school students in central science topics such as stoichiometry is problematic for their further study of chemistry and for the country meeting its need for science graduates. Successive examiner reports pointed to the lack of integration of stoichiometry concepts across the grades being the main problem. However, no study could be found which explores how stoichiometry is integrated in the South African Natural Sciences and Physical Sciences curriculum across the grades. This provided the rationale for the current study. The case study reported in this thesis thus aimed to explore integration of stoichiometry concepts in South African Natural Sciences and Physical Sciences school curricula. It involved document analysis as the method of collecting data. The research adopted the social realist paradigm, with its realist ontology and relativist epistemology. Legitimation Code Theory provided the theoretical framing. Chemistry concepts that are foundational to the understanding of stoichiometry according to literature, were chosen as root concepts for the concept mapping undertaken to identify types of integration. The concept maps revealed four stoichiometry integration themes: integration of stoichiometry concepts with symbols, integration of stoichiometry concepts with explanations, integration with applications in a chemistry context, and integration with an everyday context. These themes provided integration categories. A semantic gravity translation device was then developed for characterising the types of integration in terms of the degree of contextualisation. The results of this study show that stoichiometry integration of weaker semantic gravity is legitimated more strongly over other semantic gravity codes in the Natural Sciences and Physical Sciences curricula across all grade levels. While this has advantages in terms of knowledge-building potential, the consequence is that the integration occurs at very abstract levels that are far removed from learners’ everyday lives. The practical implication for curriculum developers involves increasing the instances of integration of stoichiometry concepts at stronger levels of semantic gravity, for a more even semantic gravity range of integration types. Natural Sciences and Physical Sciences teachers also need to source and include real-life examples for explanations and applications of stoichiometry concepts when teaching, in light of current curriculum documents focusing more on abstract forms of integration. Methodologically, this study contributes to the increased utility of semantic gravity through its exploration of integration in relation to knowledge-building potential of curriculum for hierarchical knowledge structures such as chemistry. , Thesis (MEd) -- Faculty of Education, Education, 2022
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Date Issued: 2022-10-14

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