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Exploring targeted metagenomics and untargeted metabolomics for characterising aquaponics bacterial ecology and phytochemistry

  • Authors: Abraham, Benjamin Melakail
  • Date: 2021-10-29
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/192453 , vital:45227
  • Description: Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
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  • Date Issued: 2021-10-29

Design of Immunobiosensors for Detection of Tumor-Associated Anti-P53 Autoantibodies: Method Development

  • Authors: Adeniyi, Omotayo Kayode
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/162988 , vital:41002 , 10.21504/10962/162988
  • Description: Introduction -- Experimental -- Label-Free Impedimetric Sensing of Anti-P53ab... -- Fluorescent detection of Anti-P53ab -- Peroxidase-like activity of Fe3O4@SiNP-APTES-Au@Pd... -- Colorimetric detection of Anti-P53ab , Thesis (PhD)--Rhodes University, Science Faculty, Department of Chemistry, 2020. , Detection and profiling of circulating tumor-associated autoantibodies (TAAbs) are useful for screening and early-stage diagnosis of asymptomatic lung cancer. Immunobiosensor technologies aimed to accomplish the highly sensitive, rapid and low-cost detection of TAAbs can improve the early-stage detection of lung cancer. Immunobiosensors for the detection of anti-P53-tumour associated autoantibodies have been developed in this work. The design of sensing interfaces with immobilized P53 protein (P53ag) as a sensing element layer on a solid interface was investigated. Several methods of detecting anti-P53-antibodies (anti-P53ab) were investigated. These methods are label-free detection using electrochemical impedance spectroscopy (EIS) and two label techniques. The label-free electrochemical techniques utilize gold electrode pre-modified with a conducting layer of electrochemically grafted phenylethylamine for covalent immobilization of P53ag. The limit of anti-P53ab detection with the label-free EIS was 103.0 pg.ml-1. The labeled technique developed utilizes fluorescent, and peroxidase-like nanomaterial labeled antibody as a detection probe. For the fluorescence detection, fluorescent silica nanoparticles were synthesized by overloading FITC into the silica matrix and conjugated to detection antibody (anti-IgG). The detection of the anti-P53ab was based on the dissolution of the silica nanoparticles to release the loaded dye as a signal amplification strategy. The fluorescence detection was carried out on a microplate, and magnetic bead modified P53-antigen platforms and limit of detection (LoD) were 42.0 fg.ml-1 and 3.3 fg.ml-1 for anti-P53ab; respectively. Fe3O4@SiNP-APTES-Au@Pd hybrid nanoparticles were synthesized, and their peroxidase-like activity and colorimetric detection were evaluated. The Fe3O4@SiNP-APTES-Au@Pd exhibited comparable activity to HRP. The Fe3O4@SiNP-APTES-Au@Pd was conjugated to protein-G-anti-IgG for the detection of anti-P53ab on a microplate and cellulose paper platforms. The LoD was 20.0 fg.ml-1 and 63.0 fg.ml-1 for the microplate and cellulose paper platform; respectively. The potential application of the designed immunobiosensor was evaluated in simulated serum samples. The developed sensors showed higher detection sensitivity, stability and had a lower detection limit for anti-P53ab when compared with the ELISA based detection. The results have provided alternative and effective quantification approaches to ELISA and a promising future for multiplexed detection of tumor-associated autoantibodies. The developed methodologies in this thesis could be applied for the detection of other autoantibodies in other cancer types and auto-immune diseases.
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  • Date Issued: 2020

Bioprospecting for amylases, cellulases and xylanases from ericoid associated fungi, their production and characterisation for the bio-economy

  • Authors: Adeoyo, Olusegun Richard
  • Date: 2018
  • Subjects: Uncatalogued
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10962/64327 , vital:28533
  • Description: South Africa is one of the most productive areas for ericaceous plants with about 850 identified species in the Cape Floral Region. The Albany Centre of Endemism where all fungi used in this study were isolated from, falls within this region. Ericaceous plants interact with some fungi via an association called the ericoid mycorrhizal (ERM) association. All fungi used in this study were isolated from roots of six ericaceous plants; Erica cerinthoides, Erica demissa, Erica chamissonis, Erica glumiflora, Erica caffra and Erica nemorosa. Fungal enzymes are known to play a significant role in the food, brewing, detergent, pharmaceutical and biofuel industries. The enzyme industry is among the major sectors of the world, and additional novel sources are being explored from time to time. This study focussed on amylases (amyloglucosidase, AMG), cellulases (endoglucanase) and xylanases (endo-1,4-P-xylanase) production from ERM fungal isolates. Out of the fifty-one (51), fungal isolates screened, ChemRU330 (Leohumicola sp.), EdRU083 and EdRU002 were among the fungi that had the highest activities of all the enzymes. They were tested for the ability to produce amylases and cellulases under different pH and nutritional conditions that included: carbon sources, nitrogen sources and metal ions, at an optimum temperature of 28°C in a modified Melin-Norkrans (MMN) liquid medium. Cellulase specific activity of 3.99, 2.18 and 4.31 (U/mg protein) for isolates EdRU083, EdRU002 and ChemRU330, respectively, was produced at an optimal pH of 5.0. For amylase, ChemRU330 had the highest specific activity of 1.11 U/mg protein while EdRU083 and EdRU02 had a specific activity of 0.80 and 0.92 U/mg protein, respectively, at the same pH with corresponding biomass yield of 113, 125 and 97 mg/50 ml, respectively. Increased enzyme activities and improved mycelial biomass production were obtained in the presence of supplements such as potassium, sodium, glucose, maltose, cellobiose, tryptone and peptone, while NaFe-EDTA and cobalt inhibited enzyme activity. ChemRU330 was selected to determine the consistency and amount of amylase, cellulase and xylanase formed after several in vitro subculturing events. AMG and endo-1,4-P-xylanase were found to have the most consistent production throughout the study period. The AMG was stable at 45oC (pH 5.0), retaining approximately 65% activity over a period of 24 h. The molecular mass of AMG and endo-1,4-P-xylanase were estimated to be 101 kDa and 72 kDa, respectively. The Km and kcat were 0.38 mg/ml and 70 s-1, respectively, using soluble starch (AMG). For endo-1,4-P-xylanase, the Km and Vmax were 0.93 mg/ml and 8.54 U/ml, respectively, using beechwood xylan (endo-1,4-P-xylanase) as substrate. Additionally, crude extracts of five root endophytes with unique morphological characteristics were screened for antibacterial properties and was followed by determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). L. incrustata (ChemRU330) and Chaetomium sp. extracts exhibited varying degrees of inhibition against two Gram-positive and Gram-negative bacteria. The crude extract of L. incrustata was the most effective which was found to inhibit Staphylococcus aureus (MIC: 1 mg/ml), Bacillus subtilis (MIC: 2 mg/ml) and Proteus vulgaris (MIC: 16 mg/ml). The L. incrustata displayed potential for antibacterial production and could be considered as an additional source of new antimicrobial agents in drug and food preservation. Also, the three isolates used for enzyme production were identified to genus and species levels, i.e., Leohumicola incrustata (ChemRU330), Leohumicola sp. (EdRU083) and Oidiodendron sp. (EdRU002) using both ITS and Cox1 DNA regions. The molecular analysis results indicated that these ERM mycorrhizal fungi were similar to those successfully described by some researchers in South Africa and Australia. Therefore, this study opens new opportunities for exploring ERM fungal biomolecules for the bio-economy. The promising physicochemical properties, starch and xylan hydrolysis end- products, and being non-pathogenic make AMG and endo-1,4-P-xylanase potential candidates for future applications as additives in the food industry for the production of glucose, glucose syrups, high-fructose corn syrups, and as well as the production of bioethanol. Finally, the findings of this study revealed that it is possible to produce hydrolytic enzymes from ERM fungi in vitro using chemically defined media. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2018
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  • Date Issued: 2018

Design of immunosensor for the detection of C-reactive protein using oriented antibody immobilization

  • Authors: Adesina, Abiola Olanike
  • Date: 2020
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/163080 , vital:41010 , https://dx.doi.org/10.21504/10962/163080
  • Description: Thesis (PhD)--Rhodes University, Science Faculty, Department of Chemistry, 2020.
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  • Date Issued: 2020

The design, synthesis and antiplasmodial activity of a series of halogenated fosmidomycin analogues and hybrid drugs

  • Authors: Afolayan, Anthonia Folake
  • Date: 2012
  • Subjects: Uncatalogued
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/64370 , vital:28538
  • Description: Malaria continues to be a devastating disease and a major cause of death in sub-Saharan Africa. With resistance against most of the available antimalarial drugs, there is a need for ongoing research and development of antimalarial agents. Fosmidomycin and its acetyl analogue FR900098 have been identified as potent inhibitors of Plasmodium falciparum, the causative agent of the most deadly form of malaria. Clinical trials of these agents have revealed poor absorption due to their high hydrophilicity. In the present studies the effect of halogenation of the acyl chain as well as the biological effect of extending the acyl sidechain was explored. This provided the basis on which fosmidomycin hybrids were designed to investigate the feasibility of hybrid extending into NADPH binding pocket. Synthesis of a series of halogenated FR900098 analogues was carried out in three stages. This included i) The introduction of the phosphonate group by reaction with 1,3dibromopropane in an Arbuzov reaction, ii) The introduction of a hydroxamate group by reaction of the propyl phosphonate by means of a nucleophilic substitution reaction with BocNHOBn and iii) The introduction of a halogenated acyl side chain on a protected fosmidomycin backbone. The synthesis of fosmidomycin-hybrids for which chloroquinefosmidomycin hybrids were used as the prototype, involved convergence of the two separately constructed moieties i.e. fosmidomycin and the quinoline moieties in a covalent linkage. The quinoline moiety was easily synthesized from the reaction of 4,7dichloroquinoline with 1,2-diamino ethane. The aminoquinoline so formed resulted in chloroquine-fosmidomycin hybrids 3.8 and 3.9 when reacted with halogenated FR900098 analogues. Antiplasmodial assays were conducted on the chloroquine-fosmidomycin hybrids and the halogenated fosmidomycin derivatives against the chloroquine resistant Gambian FCR-3 strain of P. falciparum. The most potent iodoacetyl fosmidomycin analogues 2.21 gave an IC50 value of 5.54 µM which is eight times more potent than the known antiplasmodial FR900098 which gave an IC50 value of 41.67 µM. All the halogenated FR900098 analogues showed better antiplasmodial activity than their non-halogenated derivatives. This indicated that the presence of halogens in the FR900098 analogues contributes to their biological Chapter 1 Literature review activity. The acetyl and propyl linked hybrids 3.8 and 3.9 showed potent antiplasmodial activity with IC50 values of 0.18 and 0.82 µM respectively. These were by far the most potent hybrids synthesized and provided leads for a new class of promising antimalarial agents. Preliminary E. coli DXR enzyme inhibition assays were carried out on the halogenated fosmidomycin analogues. The results showed good inhibition of the enzyme by the phosphonic acids of the chloroacetyl and chloropropyl analogues 2.1 and 2.2 respectively. Molecular modelling of the compounds on E. coli (PDB code: 2EGH) and P. falciparum (PDB code: 3AUA) DXR showed strong binding of the halogenated fosmidomycin analogues while the hybrids in the absence of docked NADPH showed minimum binding to the enzymes.
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  • Date Issued: 2012

The relative suitability of knowledge paradigms to indigenous African resource management and their implications for environmental bioethics, environmental policy and food security

  • Authors: Agbor Ambang, Oscar Mbi
  • Date: 2020-04
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Masters , M.Pharm
  • Identifier: http://hdl.handle.net/10962/163091 , vital:41011
  • Description: Thesis (M.Pharm)--Rhodes University, Faculty of Pharmacy, Pharmacy, 2020.
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  • Date Issued: 2020-04

A phenomenological investigation of the beginning therapist's experience of the first session of psychotherapy with the first patient

  • Authors: Allen, Jennifer Ann
  • Date: 1987
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/193129 , vital:45301
  • Description: The aim of this project is to come to an understanding of how the situation of the first session of psychotherapy with the first patient is lived by the beginning therapist and what meaning this situation holds for him. The writer's interest in this phenomenon grew out of her own experience of this situation as a clinical Masters coursework student, an experience which was of important to the writer and meaningful still as a therapist in training. In dialogue with experienced therapists the importance of this situation was again made apparant. It was the opinion of these therapists that although for some the details of this experience had become dulled by time, what remained meaningful to them was that this experience was seen as the beginning of a project which remains important to them - they identified this situation as an important moment in the history of their development as psychotherapists. In the hope that the literature pertaining to psychotherapy would throw some light on this situation, the writer turned to a number of sources in this area to discover that no literature available to her elucidated this situation in a holistic manner. This led the writer to go back to the beginning therapists themselves so that they may speak for themselves of their experience of this situation. A phenomenological method of enquiry is implemented in this study as it renders the subject matter accessible to investigation, and allows it to reveal itself as it essentially is. This project is then an attempt to come to a general description of the beginning therapist's experience of the first session of psychotherapy with the first patient and thus to articulate the structure of the beginning therapist's lived situation (world) in this context. , Thesis (MA) -- Faculty of Humanities, Psychology, 1987
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  • Date Issued: 1987

In silico analysis of plasmodium falciparum Hsp70-x for potential binding sites and hits

  • Authors: Amusengeri, Arnold
  • Date: 2017
  • Subjects: Uncatalogued
  • Language: English
  • Type: text , Thesis , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/59136 , vital:27435
  • Description: Restricted access-thesis embargoed for 1 year - release date April 2019
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  • Date Issued: 2017

Self-reports on the effectiveness of psychotherapy with therapists-in-training: an 18-month follow-up study at a psychology training clinic

  • Authors: Angus, Catherine Clare
  • Date: 1993
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/193069 , vital:45295
  • Description: The purpose of this study is to ascertain whether the clients who make use of the services of the Psychology Clinic at Rhodes University perceive the masters students being trained at the Clinic as providing adequate psychotherapy. Using a sample of 18 clients, who underwent psychotherapy at the Rhodes Psychology Clinic during 1990, a follow-up study was conducted to ascertain the perceived success of that psychotherapy. Those variables most pertinent to the outcome of psychotherapy are examined. The study uses both qualitative and quantitative methodology and shows that, overall, 89% of the clients who participated in this study perceived the psychotherapy at the Rhodes Psychology Clinic to be satisfactory. The study also highlights those factors which were perceived to be negative in the psychotherapeutic equation and it is hoped that the findings can be beneficial in planning more efficient services for the Clinic in the future. , Thesis (MA) -- Faculty of Humanities, Psychology, 1993
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  • Date Issued: 1993

Composition Portfolio

  • Authors: Appollis, Sylvester
  • Date: 201u
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/193476 , vital:45335
  • Description: Composition portfolio. , Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 201u
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  • Date Issued: 201u

In vitro pharmacological screening of thiazolidinedione-derivatives on diabetes and Alzheimer’s potential therapeutic targets

  • Authors: Arineitwe, Charles
  • Date: 2022-04
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/232171 , vital:49968
  • Description: There is an increased prevalence of diabetes and other non-communicable diseases in Sub-Saharan Africa and globally. In South Africa, the prevalence of type 2 Diabetes mellitus is currently estimated at 9.0% in people aged 30 and older and is expected to increase. Diabetes-related complications result in acute alterations in the mental state due to poor metabolic control as well as greater rates of decline in cognitive functioning with age, higher prevalence of depression and increased risk of Alzheimer’s disease. Alzheimer’s disease is the most common form of dementia in older adults and possibly contributes to 60 - 70% of cases. Alzheimer’s disease remains incurable, its progression inevitable with the currently available symptomatic therapies being palliative while the treatment of diabetes relies on insulin preparations and other glucose-lowering agents. Current treatment options have numerous side effects such as hypoglycaemia, diarrhoea, weight gain and abnormal liver function. This has geared the investigation of new generations of small molecules which exhibit improved efficacy and safety profiles. On this basis, several studies have shown that thiazolidinediones and their corresponding derivatives exhibit a broad spectrum of biological activities including anti-inflammatory, and antioxidant activities. Furthermore, recent evidence from experimental, epidemiological, and clinical studies highlight the utility of antioxidants for treating diabetes and its complications. Interestingly, there is increasing evidence that links diabetes and Alzheimer’s disease due to their pathophysiology and suppressing glycaemia has been shown to be beneficial in Alzheimer’s disease treatment. Accordingly, the aim of this study, was to evaluate the anti-diabetic and anti-Alzheimer’s properties of four novel synthesized thiazolidinedione-derivatives owing to their antioxidant properties. Methods The aim of this study was achieved through performing ferric reducing antioxidant power activity, 2,2’-Diphenyl-1-Picry Hydrazyl radical scavenging activity, α-amylase inhibition, α-glucosidase inhibition, aldose reductase inhibition, protein tyrosine phosphatase-1B inhibition, dipeptidyl peptidase-4 inhibition, acetylcholinesterase inhibition, matrix metalloproteinase-1 inhibition, and β-amyloid aggregation inhibition assays. In addition, peroxisome proliferator-activated receptor-γ activation was performed through docking studies. To establish physicochemical properties of TZD derivatives investigated, further in-silico studies were done using SwissADME tools. Results To this end, in-vitro and in-silico studies were successfully performed. In-silico ADME profiling predicted these derivatives to be drug-like with moderate to good solubility in the GI and not blood-brain barrier permeable. Furthermore, docking of these molecules against PPARγ predicted a similar mode of action to that of thiazolidinediones using Rosiglitazone as the standard drug with TZDD2 and TZDD4 forming equivalent conformations to that of Rosiglitazone in the same binding site and TZDD3 having an equivalent LBE to that of Rosiglitazone (-8.84 and -8.63kcal/mol respectively). In-vitro evaluation predicted a moderate antioxidant activity with TZDD2 and 3 exhibiting the highest FRAP activity and DPPH radical scavenging activity. Furthermore, enzymatic inhibition assays showed a relative inhibition activity with TZDD3 exhibited > 100% inhibition in concentrations ≥ 30 μg/mL and TZDD1, 2 and 4 exhibited ≥ 50% inhibition activity in all the concentrations (10, 20, 30, 40 and 50 μg/mL) in the α-amylase inhibition assay. Similarly, in the α-glucosidase inhibition assay, all the four derivatives exhibited a concentration dependent activity with TZDD3 showing the most activity. All the four derivatives exhibited ≥ 30% inhibition in the aldose reductase inhibition assay except TZDD1 at 10 μg/mL. TZDD4 exhibited a concentration dependent inhibition activity in the protein tyrosine phosphatase-1B inhibition assay. Interestingly, TZDD3 showed a decreasing inhibition activity as its concentration increased from 10 μg/mL through to 50 μg/mL. In the dipeptidyl peptidase–4 inhibition assay, TZDD2 and TZDD4 exhibited ≥ 20% inhibition activity across all the concentrations and in the acetylcholinesterase assay, TZDD1, 3 and 4 exhibited ≥ 25% across all the concentrations. Interestingly, in the matrix metalloproteinase-1 inhibition assay, some of these derivatives exhibited partial activation activity and partial inhibition with TZDD1 showing activation in concentrations 10 and 20 μg/mL and inhibition in concentrations 30, 40 and 50 μg/mL. TZDD4 showed activation in all the concentrations. In the β-amyloid aggregation assay, all the four derivatives showed inhibition activity ≥ 10% except TZDD1 at 50 μg/mL. Conclusions Diabetes mellitus and Alzheimer’s disease are a type of pathology of global concern, and several researchers worldwide have strived to search for novel therapeutic treatments and prevention for diabetes as well as Alzheimer’s disease. Recent studies provide a direct link v between diabetes mellitus and Alzheimer’s disease, and the need to find novel drugs that can mitigate these two is of increasing interest. In our search for antidiabetic and anti-Alzheimer’s activity, TZD derivatives (TZDD1, TZDD2, TZDD3 and TZDD4) exhibited good antioxidant activity, anti-hyperglycaemic activity and a relatively promising anti-Alzheimer’s activity. This was observed from the in vitro evaluation performed which included α – amylase, α – glucosidase, aldose reductase, PTP1B, DPP4, amyloid β aggregation, and AChE inhibition assays. Furthermore, docking of the derivatives against PPARγ predicted a similar molecular interaction to that of thiazolidinediones using Rosiglitazone as the standard drug. Furthermore, in silico ADME profiling predicted the derivatives to have moderate to good solubility in the GI (good GI bioavailability), and also exhibited excellent drug likeness. However, they are predicted not permeate the BBB. Further in silico studies and in vivo should be conducted to establish toxicities, as well as drug delivery to the brain for effective therapeutic effect against Alzheimer’s disease. , Thesis (MSc) -- Faculty of Pharmacy, Pharmacology, 2022
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  • Date Issued: 2022-04

An investigation of traveling ionospheric disturbances (TIDs) in the SANAE HF radar data

  • Authors: Atilaw, Tsige Yared
  • Date: 2022-04
  • Subjects: Uncatalogued
  • Language: English
  • Type: Doctoral thesis , text
  • Identifier: http://hdl.handle.net/10962/232377 , vital:49986 , DOI 10.21504/10962/232377
  • Description: This thesis aims to study the characteristics of traveling ionospheric disturbances (TIDs) as identified in the radar data of the South African National Antarctic Expedition (SANAE) Super Dual Auroral Radar Network (SuperDARN) radar located in Antarctica. For this project, 22 TIDs were identified from visual inspection of range time-intensity (RTI) plots of backscattered power and Doppler velocity parameters of the SANAE radar between 2005âAS2015. These events were studied to determine their characteristics and driving mechanisms. Where good quality data were available, the SANAE HF radar data were supplemented by Halley radar data, which has large area of overlapping field of view (FOV) with the SANAE radar, and also by GPS TEC data. This provided a multi-instrument data analysis of some TID events. Different spectral analysis methods, namely the multitaper method (MTM), Fast Fourier transform (FFT) and the Lomb-Scargle periodogram were used to obtain spectral information of the observed waves. The advantage of using multiple windowing in MTM over the traditional windowing method was illustrated using one of the TID events. In addition, the analytic signal of the wave from the MTM method was used to estimate the instantaneous phase velocity and propagation azimuth of the wave, which was able to track the change in the characteristics of the medium-scale TID (MSTID) efficiently throughout the duration of the event. This is a clear advantage over other windowing techniques. The energy contribution by this MSTID through Joule heating was estimated over the region where spectral analysis of both SANAE and Halley data showed it to be present. The majority of the TIDs (65.4%) could be classified as MSTIDs with periods of 20–60 minutes, velocities of 50–333 ms􀀀1 and wavelengths of 129–833 km. The TID occurrence rate was high around the March equinox with 12 out of the 16 event days being during March–May. March had a particularly high number of occurrences of TIDs (46%). The majority of the TIDs observed during this month propagated northward or southeastward. In terms of prevailing geomagnetic conditions, 6 out of 16 event days were geomagnetically quiet, while 10 occurred during geomagnetic storms and substorms. During quiet conditions, TIDs could be linked to Es and polarised electric fields in 2 of these events. The other quiet time events could not be related to Es instability and polarised electric field either because their exact propagation direction could not be determined or data quality from the Es region scatter was too poor to perform spectral analysis. The storm-/substorm-related TIDs are possibly generated through Joule heating, the Lorentz force and energetic particle precipitation. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2022
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  • Date Issued: 2022-04

Potential of the Gravel Filter Towers, Pilot-scale Filter system and Biochar/Clay adsorbents for Bio-Physicochemical remediation and Desalination of greywater

  • Authors: Bani, Siphumze
  • Date: 2021-10-29
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/188375 , vital:44748
  • Description: Thesis embargoed until 2023 , Thesis (MSc) -- Faculty of Science, Rhodes University Biotechnology Innovation Centre, 2021
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  • Date Issued: 2021-10-29

Contributions to the study of nonholonomic Riemannian manifolds

  • Authors: Barrett, Dennis Ian
  • Date: 2017
  • Subjects: Uncatalogued
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10962/7554 , vital:21272 , DOI https://doi.org/10.21504/10962/7554
  • Description: In this thesis we consider nonholonomic Riemannian manifolds, and in particular, left- invariant nonholonomic Riemannian structures on Lie groups. These structures are closely related to mechanical systems with (positive definite) quadratic Lagrangians and nonholo- nomic constraints linear in velocities. In the first chapter, we review basic concepts of non- holonomic Riemannian geometry, including the left-invariant structures. We also examine the class of left-invariant structures with so-called Cartan-Schouten connections. The second chapter investigates the curvature of nonholonomic Riemannian manifolds and the Schouten and Wagner curvature tensors. The Schouten tensor is canonically associated to every non- holonomic Riemannian structure (in particular, we use it to define isometric invariants for structures on three-dimensional manifolds). By contrast, the Wagner tensor is not generally intrinsic, but can be used to characterise flat structures (i.e., those whose associated parallel transport is path-independent). The third chapter considers equivalence of nonholonomic Rie- mannian manifolds, particularly up to nonholonomic isometry. We also introduce the notion of a nonholonomic Riemannian submanifold, and investigate the conditions under which such a submanifold inherits its geometry from the enveloping space. The latter problem involves the concept of a geodesically invariant distribution, and we show it is also related to the curvature. In the last chapter we specialise to three-dimensional nonholonomic Riemannian manifolds. We consider the equivalence of such structures up to nonholonomic isometry and rescaling, and classify the left-invariant structures on the (three-dimensional) simply connected Lie groups. We also characterise the flat structures in three dimensions, and then classify the flat structures on the simply connected Lie groups. Lastly, we consider three typical examples of (left-invariant) nonholonomic Riemannian structures on three-dimensional Lie groups, two of which arise from problems in classical mechanics (viz., the Chaplygin problem and the Suslov problem). , Thesis (PhD) -- Faculty of Science, Mathematics (Pure and Applied), 2017
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  • Date Issued: 2017

"Burnout" in children's home houseparents

  • Authors: Bath, Peter John
  • Date: 1983
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/193118 , vital:45300
  • Description: Aimed at replicating the results of an American study into "Burnout" in Group Home houseparents, this research had the following aims: 1) To ascertain the validity and reliability of the instrument used in the original study and presented as a "useful measure of burnout”. 2) To establish whether this line of research, within a highly problematic research field, can at present offer any guidelines in the resolution of the current staffing crisis faced by South African children's homes. 3} To describe more closely the burnout syndrome. 4) To study possible etiological factors within a local context. Sixty three houseparents completed questionaires and three independent measures of burnout were obtained. The results were regarded as having failed to replicate those of the original study. The reason for this was found to be the low validity of the original instrument. The main conclusion drawn was that the line of research adopted in the original study can offer only very tentative guidelines towards the resolution of the staffing crisis faced until such time as valid and reliable instruments to measure burnout have been developed. Many of the suggested relationships between situational variables and ones of personal characteristics were confirmed for the local population of houseparents. , Thesis (MSocSci) -- Faculty of Humanities, Psychology, 1983
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  • Date Issued: 1983

The role of Stress Inducible Protein 1 (STI1) in the regulation of actin dynamics

  • Authors: Beckley, Samantha Joy
  • Date: 2015
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10962/193941 , vital:45409
  • Description: Stress-inducible protein 1 (STI1) otherwise known as Hop (Hsp70/Hsp90 organising protein) is a highly conserved abundant co-chaperone of the Hsp70 and Hsp90 chaperones. STI1 acts as an adapter protein, where it regulates the transfer of protein substrates from Hsp70 to Hsp90 during the assembly of a number of chaperone-client protein complexes. The role of STI1 associating independently with non-chaperone proteins has become increasingly prominent. Recent data from colocalisation and co-sedimentation analyses in our laboratory suggested a direct interaction between STI1 and the cytoskeletal protein, actin. However, there was a lack of information on the motifs which mediated this interaction, as well as the exact role of STI1 in the regulation of cytoskeletal dynamics. Two putative actin binding motifs, DAYKKK (within the TPR2A domain) and a polyproline region (after the DP1 domain), were identified in mammalian STI1. Our data from in vitro interaction studies including surface plasmon resonance and high speed co-sedimentation assays suggested that both TPR1 and TPR2AB were required for the STI1-actin interaction, and peptides corresponding to either the DAYKKK or the polyproline motif, alone or in combination, could not block the STI1-actin interaction. Full length mSTI1 was shown to have ATPase activity and when combined with actin an increase in ATPase activity was seen. Ex vivo studies using STI1 knockdown shRNA HEK293T cells and non-targeting control shRNA HEK293T cells showed a change of F-actin morphology as well as reduction in levels of actin-binding proteins profilin, cofilin and tubulin in the STI1 knockdown cells. These data extend our understanding of the role of STI1 in regulating actin dynamics and may have implications for cell migration. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2015
  • Full Text:
  • Date Issued: 2015

Biochemical characterisation and small molecule modulation of the interaction between two cytosolic Hsp70s from Trypanosoma brucei and potential co-chaperones

  • Authors: Bentley, Stephen John
  • Date: 2018
  • Subjects: Uncatalogued
  • Language: English
  • Type: text , Thesis , Doctoral , PhD
  • Identifier: http://hdl.handle.net/10962/63402 , vital:28407
  • Description: Expected release date-April 2019
  • Full Text:
  • Date Issued: 2018

A Smaller Circle

  • Authors: Bhikha, Nasira
  • Date: 2022-04
  • Subjects: Uncatalogued
  • Language: English
  • Type: Master's thesis , text
  • Identifier: http://hdl.handle.net/10962/232427 , vital:49991
  • Description: My thesis is a collection of prose forms weaving my identity as a South African woman of colour, my observations of life through personal, cultural and sociological lenses, where traditions are constantly challenged and evolving. The collection focuses on the untold and unresolved, using fiction as a tool of pushback and psychological reflection. I am motivated by writers who use what I would term reflective expressionism to evoke empathy by tapping into innate, universal emotions. In particular Tiff Holland’s vivid telling of family in the novella Betty Superman where she navigates complex relationships, and bell hooks’ memoirs Bone Black: Memories of Girlhood written as poetic vignettes in fluctuating points of view to draw attention to the intricacies of social structures. Joanna Walsh’s Vertigo has strongly influenced my approach to writing through her compelling imagery and use of motif in fragmented prose that delves into the psyche of her characters. I am also inspired by Lidia Yuknavitch’s visceral use of language, identifying with her invitation: “You deserve to sit at the table. The radiance falls on all of us.” , Thesis (MACW) -- Faculty of Humanities, School of Languages, 2022
  • Full Text:
  • Date Issued: 2022-04

A study of four-dimensional oscillator groups and the associated left-invariant control affine systems

  • Authors: Biggs, Rory
  • Date: 2012
  • Subjects: Uncatalogued
  • Language: English
  • Type: thesis , text , Masters , MSc
  • Identifier: http://hdl.handle.net/10962/164941 , vital:41186
  • Description: Thesis (MSc)--Rhodes University, Faculty of Science, Department of Mathematics, 2012
  • Full Text:
  • Date Issued: 2012

Neutral Atomic Hydrogen in Gravitationally Lensed Systems

  • Authors: Blecher, Tariq Dylan
  • Date: 2021-10-29
  • Subjects: Uncatalogued
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10962/192776 , vital:45263
  • Description: Thesis (PhD) -- Faculty of Law, Law, 2021
  • Full Text:
  • Date Issued: 2021-10-29
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