List of Titles

CdTe quantum dots functionalized with 4-amino-2, 2, 6, 6-tetramethylpiperidine-N-oxide as luminescent nanoprobe for the sensitive recognition of bromide ion

- Adegoke, Oluwasesan, Hosten, Eric, McCleland, Cedric, Nyokong, Tebello

Authors: Adegoke, Oluwasesan , Hosten, Eric , McCleland, Cedric , Nyokong, Tebello
Date: 2012
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/244393 , vital:51253 , xlink:href="https://doi.org/10.1016/j.aca.2012.01.040"
Description: A novel bromide ion-selective modified nanoprobe sensor based on 4-amino-2,2,6,6-tetramethylpiperidine-N-oxide (4AT)-functionalized CdTe quantum dots (QDs-4AT) has been developed. Fluorescence quenching of the QDs by 4AT was observed. The functionalized QDs-4AT nanoprobe allowed a highly sensitive determination of bromide ion via analyte-induced change in the photoluminescence (fluorescence recovery) of the modified QDs. A detection limit of 0.6 nM of bromide ion was obtained, while the interfering effect of other inorganic cations and anions was investigated to examine the selectivity of the nanoprobe. The linear range was between 0.01 and 0.13 μM. Combined fluorescence lifetime and electron paramagnetic resonance measurements confirmed electron transfer processes between bromide ion and QDs-4AT.
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Date Issued: 2012

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Deposition of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shells around CdSeTe alloyed core quantum dots: effects on optical properties

- Adegoke, Oluwasesan, Nyokong, Tebello, Forbes, Patricia B C

Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
Date: 2015
Language: English
Type: Article
Identifier: vital:7289 , http://hdl.handle.net/10962/d1020342
Description: In this work, we synthesized water-soluble L-cysteine-capped alloyed CdSeTe core quantum dots (QDs) and investigated the structural and optical properties of deposition of each of CdS, CdS/ZnSe and CdS/ZnSe/ZnS shell layers. Photophysical results showed that the overcoating of a CdS shell around the alloyed CdSeTe core [quantum yield (QY) = 8.4%] resulted in effective confinement of the radiative exciton with an improved QY value of 93.5%. Subsequent deposition of a ZnSe shell around the CdSeTe/CdS surface decreased the QY value to 24.7%, but an increase in the QY value of up to 49.5% was observed when a ZnS shell was overcoated around the CdSeTe/CdS/ZnSe surface. QDs with shell layers showed improved stability relative to the core. Data obtained from time-resolved fluorescence measurements provided useful insight into variations in the photophysical properties of the QDs upon the formation of each shell layer. Our study suggests that the formation of CdSeTe/CdS core/shell QDs meets the requirements of quality QDs in terms of high photoluminescence QY and stability, hence further deposition of additional shells are not necessary in improving the optical properties of the core/shell QDs. Copyright © 2015 John Wiley & Sons, Ltd. , Original publication is available at http://dx.doi.org/10.1002/bio.3013
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Date Issued: 2015

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Conjugation of mono-substituted phthalocyanine derivatives to CdSe@ ZnS quantum dots and their applications as fluorescent-based sensors

- Adegoke, Oluwasesan, Nyokong, Tebello

Authors: Adegoke, Oluwasesan , Nyokong, Tebello
Date: 2014
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/189842 , vital:44936 , xlink:href="https://doi.org/10.1016/j.synthmet.2013.11.016"
Description: Unsymmetrically substituted derivatives of aluminium amino phthalocyanines were synthesized for the first time, fully characterized and conjugated to CdSe@ZnS quantum dots (QDs). The conjugates were employed as fluorescence-based sensors for anion sensing. Among the anions that enhanced the fluorescence of the probe, fluoride ion was chosen as the test ion to test the efficacy of the probe. Förster resonance energy transfer from the QDs to the phthalocyanine was observed as an indication for the fluorescence quenching of the QDs upon binding to the phthalocyanine. The fluorescence of the linked QDs was progressively enhanced, and linearly proportional to increasing concentrations of fluoride ion. The type of substituent attached to the phthalocyanine ring influenced the efficiency of fluorescence enhancement. The proposed nanoprobe has been employed to detect fluoride ion in cell culture medium and tap water.
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Date Issued: 2014

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Unsymmetrically Substituted Nickel Triazatetra-Benzcorrole and Phthalocynanine Complexes: Conjugation to Quantum Dots and Applications as Fluorescent “Turn ON” Sensors

- Adegoke, Oluwasesan, Nyokong, Tebello

Authors: Adegoke, Oluwasesan , Nyokong, Tebello
Language: English
Type: Article
Identifier: vital:7311 , http://hdl.handle.net/10962/d1020403
Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs. , Original publication is available at http://dx.doi.org/10.1007/s10895-013-1317-4
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Effects of analytes on the fluorescence properties of CdTe@ ZnS quantum dots decorated with cobalt tetraamino-phthalocyanine

- Adegoke, Oluwasesan, Nyokong, Tebello

Authors: Adegoke, Oluwasesan , Nyokong, Tebello
Date: 2014
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/189829 , vital:44935 , xlink:href="https://doi.org/10.1016/j.jlumin.2013.09.079"
Description: In this work, we have carried out an investigation on the effects of different biologically active analytes on the fluorescence response of glutathione-capped CdTe@ZnS quantum dots (QDs)-colbalt tetraamino-phthalocyanine nanoconjugate system. Firstly, fluorescence quenching occurred. Experimental results showed that some analytes either “turned on”, others further quenched or showed no effect on the fluorescence emission of the nanoprobe.
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Date Issued: 2014

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Unsymmetrically substituted nickel triazatetra-benzcorrole and phthalocynanine complexes

- Adegoke, Oluwasesan, Nyokong, Tebello

Authors: Adegoke, Oluwasesan , Nyokong, Tebello
Date: 2014
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/189818 , vital:44934 , xlink:href="https://doi.org/10.1007/s10895-013-1317-4"
Description: We report on the design and application of fluorescent nanoprobes based on the covalent linking of L-glutathione-capped CdSe@ZnS quantum dots (QDs) to newly synthesized unsymmetrically substituted nickel mercaptosuccinic acid triazatetra-benzcorrole (3) and phthalocyanine (4) complexes. Fluorescence quenching of the QDs occurred on conjugation to complexes 3 or 4. The nanoprobes were selectively screened in the presence of different cations and Hg2+ showed excellent affinity in “turning ON” the fluorescence of the nanoprobes. Experimental results showed that the sensitivity of QDs-4 towards Hg2+ was much higher than that of QDs-3 nanoprobe. The mechanism of reaction has been elucidated based on the ability of Hg2+ to coordinate with the sulphur atom of the Ni complex ring and apparently “turn ON” the fluorescence of the linked QDs.
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Date Issued: 2014

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The design of quantum dots and their conjugates as luminescent probes for analyte sensing

- Adegoke, Oluwasesan

Authors: Adegoke, Oluwasesan
Date: 2014
Subjects: Quantum dots Anolytes Luminescent probes Luminescence spectroscopy Phthalocyanines Nanoparticles
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:4457 , http://hdl.handle.net/10962/d1010866
Description: The design and applications of quantum dots (QDs) as fluorescent probes for analyte sensing is presented. Cadmium based thiol-capped QDs were employed as probe for the detection of analytes. Comparative studies between core CdTe and core-shell CdTe@ZnS QDs showed that the overall sensitivity and selectivity of the sensor was dependent on the nature of the capping agent and the QDs employed, hence making CdTe@ZnS QDs a more superior sensor than the core. To explore the luminescent sensing of QDs based on the fluorescence “turn ON” mode, L-glutathione-capped CdTe QDs was conjugated to 4-amino-2,2,6,6-tetramethylpiperidine-N-oxide (4AT) to form a QDs-4AT conjugate system. The QDs-4AT nanoprobe was highly selective and sensitive to the detection of bromide ion with a very low limit of detection. Subsequently, metallo-phthalocyanines (MPcs) were employed as host molecules on the surface of QDs based on the covalent linking of the QDs to the MPc. Elucidation of the reaction mechanism showed that the fluorescence “turn ON” effect of the QDs-MPc probe in the presence of the analyte was due to axial ligation of the analytes to the Pc ring. Studies showed that the type of substituent attached to the MPc ring influenced the overall sensitivity of the probe. Additionally, a comparative investigation using newly synthesized phthalocyanine and triaza-benzcorrole complexes was conducted when these complexes were conjugated to CdSe@ZnS QDs for analyte sensing. Results showed that the triaza-benzcorrole complex can be employed as a host-molecule sensor but displayed a lower sensitivity for analyte sensing in comparison to the phthalocyanine complex.
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Date Issued: 2014

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Structural and optical properties of alloyed quaternary CdSeTeS core and CdSeTeS/ZnS core–shell quantum dots

- Adegoke, Oluwasesan, Nyokong, Tebello, Forbes, Patricia B C

Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B C
Date: 2015
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/193575 , vital:45349 , xlink:href="https://doi.org/10.1016/j.jallcom.2015.05.083"
Description: Synthesis of fluorescent alloyed quantum dots (QDs) with unique optical properties suitable for a wide array of chemical, physical and biological applications is of research interest. In this work, highly luminescent and photostable alloyed quaternary CdSeTeS core QDs of two different sizes were fabricated via the organometallic hot-injection synthetic route. Characterization of the nanocrystals were performed using TEM, XRD, UV/vis and fluorescence spectrophotometric techniques. We have demonstrated in this work that the well fabricated alloyed quaternary CdSeTeS core QDs possess unique optical properties that are advantageous over conventional core/shell systems. Formation of the CdSeTeS/ZnS core/shell with the desired optical properties comes with a number of challenges, hence the advantages of the quaternary alloyed core over the core/shell QDs are (i) avoidance of the challenging process of determining the proper shell thickness which can provide the desired optical properties in the core/shell system and (ii) avoidance of the lattice-induced mismatch between the core and the shell material which can either lead to incomplete exciton confinement or dislocation at the core/shell interface.
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Date Issued: 2015

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Photophysical properties of a series of alloyed and non-alloyed water-soluble l-cysteine-capped core quantum dots

- Adegoke, Oluwasesan, Nyokong, Tebello, Forbes, Patricia B

Authors: Adegoke, Oluwasesan , Nyokong, Tebello , Forbes, Patricia B
Date: 2017
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/188486 , vital:44758 , xlink:href="https://doi.org/10.1016/j.jallcom.2016.10.276"
Description: Photophysical properties of quantum dots (QDs) such as their photoluminescence (PL) quantum yield (QY), exciton lifetime and PL stability are important parameters used to unravel their chemical and physical characteristics. In this work, we have comparatively investigated the photophysical properties of a series of L-cysteine-capped non-alloyed (CdTe and CdSe) and alloyed (CdZnTe, CdSeS, CdSeTe and CdSeTeS) core QDs. Each of the QDs varied in their size and PL emission wavelength. We observe no physical relationship between the PL QY of the QDs and their PL stability. Based on the PL stability assessment, CdTe QDs with a high PL QY value of 88% exhibited poor PL stability while moderate PL stability was observed for CdZnTe (QY = 78%); CdSe (QY = 3%); and CdSeTe QDs (QY = ∼3%). Alloyed CdSeS (QY = ∼69%) and CdSeTeS (QY = 23%) QDs exhibited good PL stability and can serve as potential fluorophores for a wide range of chemical and biological applications. Generally, it is proposed that the structural nature of the QDs played a significant role in their overall photophysical properties. The information provided in this work will assist in the selection of core QDs suitable for different applications.
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Date Issued: 2017

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Interaction of CdTe quantum dots with 2, 2-diphenyl-1-picrylhydrazyl free radical

- Adegoke, Oluwasesan, Chidawanyika, Wadzanai J U, Nyokong, Tebello

Authors: Adegoke, Oluwasesan , Chidawanyika, Wadzanai J U , Nyokong, Tebello
Date: 2012
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/245751 , vital:51402 , xlink:href="https://doi.org/10.1007/s10895-011-1012-2"
Description: The interaction of 2,2-diphenyl-1-picrylhydrazyl (DPPH●) free radical with thiol-capped CdTe quantum dots (QDs) has been studied by UV–vis spectroscopy, steady state and time resolved fluorescence measurements. Addition of DPPH● radical to CdTe QDs resulted in fluorescence quenching. The interaction occurs through static quenching as this was confirmed by fluorescence lifetime measurements. Time course absorption studies indicates that DPPH● may be reduced by interaction with QDs to the substituted hydrazine form (2,2-diphenyl-1-picrylhydrazine) DPPH-H. The mechanism of fluorescence quenching of CdTe QDs by DPPH● is proposed.
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Date Issued: 2012

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Assessing teaching strategies of grade four English second language teachers in Amathole District, Eastern Cape Province, South Africa

- Adegoriolu, Emmanuel Tobi

Authors: Adegoriolu, Emmanuel Tobi
Date: 2018
Subjects: Education--South Africa English language--Study and teaching--Foreign speakers Second language acquisition
Language: English
Type: Thesis , Masters , Applied Linguistics
Identifier: http://hdl.handle.net/10353/15474 , vital:40411
Description: The intention of this study was to assess the teaching strategies of Grade 4 English second language teachers in the Amathole district of the Eastern Cape. The objectives of the study were firstly, to identify the teaching strategies currently employed by Grade 4 teachers in the teaching of English as a second language in selected schools in Amathole district of the Eastern Cape in South Africa. Secondly, the study sought to establish how the existing teaching strategies impacted on the performance of the learners of English as a second language in the selected schools in Amathloe district of the Eastern Cape, and to establish the teachers‟ perceptions on the most effective teaching strategies in the selected schools. The study used translanguaging and communicative language teaching as the theoretical lens and guide in data collection and analysis. The study employed the use of mixed methods of both quantitative and qualitative research design. Data was collected through the use of eight comprehensive classroom observations and eight teacher questionnaires in four different primary schools. The conclusion of the study as established in the outcome of data showed that there was no recommended teaching strategy by the Department of Education for English second language teachers teaching Grade 4. The study observed that the language teachers made use of various teaching strategies in the instruction of Grade 4 learners. In addition, it was concluded that the placement of the English language subject on the timetable affected the performance of young learners during the summer period. Moreover, the absence of teacher-learner cordial relationship compromised learning outcomes and performance of Grade 4 learners in the skills of English second language. The study recommends that teachers of English as a second language be trained on communicative language teaching in order to achieve positive outcomes in the classroom.
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Date Issued: 2018

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Parents’ involvement in education of their children: case study of two selected secondary schools in the Amathole West District

- Adelabu, O J

Authors: Adelabu, O J
Date: 2020-10
Subjects: Education -- Parent participation , Parent-teacher relationships
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10353/19969 , vital:44857
Description: Parents’ involvement is a very important element that has an influence on children’s education. However, research has shown that parents’ involvement is the biggest challenge facing South African schools. The study sought to investigate parents’ involvement in the education of their children at secondary school in Amathole West District, Eastern Cape Province of South Africa. The study was underpinned by Epstein’s theory of parental involvement and the Ecological framework. A qualitative approach was adopted in this study which was located within an interpretivist paradigm and used a case study approach with a sample of 26 participants which includes (2 school principals, 6 educators, 6 parents and 12 learners) were selected conveniently, data was collected using focus group discussions, interviews and document analysis. The study revealed that although schools have employed various strategies to improve parental involvement in their children’s education, there are still challenges which inhibit the effectiveness of these strategies. The study also revealed that most parents are unable to get involved as expected by the school due to some challenges such as poverty, unemployment, educational background, distance and illiteracy. Consequently, the study recommended that parents must be more actively involved in the school and collaborate with their children’s teacher in order to bring out the best in their children. Furthermore, to ensure effective parents’ involvement, schools may have activities that can develop, improve and encourage parents’ involvement in such areas as parenting, communication, learning at home, volunteering, decision making and community collaboration. , Thesis (MEd) -- Faculty of Education, 2020
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Date Issued: 2020-10

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Incidence and molecular characterization of Hepatitis E virus from swine herds in the Eastern Cape province, South Africa

- Adelabu, Olusesan Adeyemi

Authors: Adelabu, Olusesan Adeyemi
Date: 2016
Subjects: Hepatitis -- South Africa -- Eastern Cape Virology -- South Africa -- Eastern Cape
Language: English
Type: Thesis , Masters , MSc
Identifier: http://hdl.handle.net/10353/13966 , vital:39734
Description: Hepatitis E virus-mediated infection is a serious public health concern in economically developing nations of the world. Globally, four major genotypes of HEV have been documented and the swine HEV identified to date in different countries belongs to either genotype 3 or 4. It has been reported to cross species barrier and cause infections in humans. Hence, Hepatitis E has been suggested to be zoonotic owing to the increase of evidence through various studies. Thus far, genotypes 1 and 2 are exclusively found in human population. However, little data are available regarding the occurrence of HEV in South Africa, especially in the Eastern Cape Province. Hence, this study was designed to assess the prevalence of Hepatitis E Virus among swine herd in selected communal and commercial farms in the Eastern Cape Province of South Africa. A total of 160 faecal samples were collected from swine herds in Amathole and Chris Hani District Municipalities of Eastern Cape Province and screened for the presence of HEV. Faecal samples were collected, using sterile swabs, from swine between the age of 2 to 6 months old, placed on ice and transported to the laboratory for further analysis. Viral RNA extraction was carried out followed by nested reverse-transcriptase polymerase chain reaction was used for amplification, after which the amplified products were examined by electrophoresis and viewed under ultraviolet illumination. The positive PCR products were sent for sequencing. Of the 160 faecal samples screened, only seven were positive (4.4percent) for HEV. The nucleotide sequence analyses revealed isolates UFT 01-03 sharing 82percent to 99percent identities with other strains with accession numbers KX896664, KX896665 and KX896666 and UMCF 01-04 with KX896667, KX896668, KX896669 and KX896670 from different regions of the world Phylogenetic analysis also showed that all seven isolates from this study clustered with both human and swine HEV from different geographical regions of the world especially with Japan Human and swine strains, Netherland swine HEV strains (AY032758, AF332620) and human HEV strain from France (JQ763611). We conclude that HEV is present among swine in the Eastern Cape Province, albeit in low incidence, and this does have public health implications. There is need for maintenance of high hygienic standards in order to prevent human infections through swine faecal materials and appropriate cooking of pork is highly advised.
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Date Issued: 2016

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A qualitative assessment of the achievement of gender equality under education for all (EFA) goals : study of Lagos State, Nigeria

- Adeleke, Adawi Adeola

Authors: Adeleke, Adawi Adeola
Date: 2018
Subjects: Sex discrimination in education -- Nigeria Sexism in education -- Nigeria Educational equalization -- Nigeria
Language: English
Type: Thesis , Doctoral , Education
Identifier: http://hdl.handle.net/10353/9500 , vital:34357
Description: The importance of education cannot be overemphasized. Education has been identified as the most critical instrument for empowering individuals with the necessary knowledge and skills, which can give them access to productive employment. Also, the future of a country is based on the quality of education acquired by its citizens which helps in transforming it from pre-literate to contemporary nationhood. Many international treaties and initiatives in the world have made special provisions for education as a duty of every government which must be given to every citizen as of right, irrespective of gender or social class. Amongst these international initiatives is the Education for All (EFA) Goals, a time-bound global movement towards the provision of education for every one led by the United Nations Educational, Scientific and Cultural Organization (UNESCO). There are six goals in all. This study investigated one of the EFA goals, the goal 5. The aim of the study was a qualitative assessment of the achievement of gender equality goal under the Education for All (EFA) goals, a study of Lagos State, Nigeria. The theoretical framework of the study is informed by the Social Justice Theory and the Social Justice Praxis Theory. Scholarly works and literatures on girl-child education, gender and education, and gender balancing in education were reviewed. The study followed qualitative research approach which utilizes an interpretive research paradigm that provides a collective voice from the participants. The research area was purposively selected as Lagos State being a former capital of Nigeria and still the commercial nerve centre of the nation. Although it is the smallest state in Nigeria in term of size, it remains the most populous in the country with a projected population of 20,546,999 (13.5percent Nigeria’s total population). A sample of 16 participants were purposively selected because they were the officers directly in charge of the implementation government policies on education in the State. The data was collected through in-depth recorded interview sessions and secondary data were sourced through official documents downloaded online and from Lagos State Ministry of Education. Based on the thematic analysis of the data collected, the study found out that the State government had established policies and measures to provide qualitative education for all the citizens on a non-discriminatory basis. Thus, the goal of gender parity in terms of enrollment of boys and girls has been relatively achieved in the state. However, there were still some challenges of equality in the learning process and outcome. The study therefore recommends that schools should be made attractive and conducive as possible to assist the educational attainment of any student. This could be achieved by promoting positive values and attitudes towards education, all the stakeholders in the education sector must be involved in the business of running the school. There should also be a form of resourcing and expansion of the school facilities through the Public - Private Partnership in education.
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Date Issued: 2018

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Ultraprecision Diamond Turning of Monocrystalline Germanium

- Adeleke, Adeniyi Kehinde

Authors: Adeleke, Adeniyi Kehinde
Date: 2021-04
Subjects: Precision , Diamond Turning
Language: English
Type: Master's theses , Thesis
Identifier: http://hdl.handle.net/10948/44453 , vital:37835
Description: Infrared lens production demands a surface with a high degree of accuracy and integrity. Surface roughness is a critical index of the measure of any product’s surface integrity. As a result of this, ultra-high machining technology has enjoyed extensive application, due to the continuous request for components within the range of 1 – 10nm roughness value. This technology has brought about the increased productivity and manufacture of quality products with a top-notch surface finish. Brittle materials such as germanium are hard to machine through the conventional processes such as lapping and polishing. Hence, the ultra-precision machining technology based on single point diamond turning (SPDT), is now been applied to machine germanium in the ductile mode, where material chip removal occurs by plastic deformation instead of a brittle fracture. During machining, selecting the optimal cutting conditions which includes cutting parameters and tool geometry, will not only improve productivity but ensure the minimisation of operating cost. In this research work, SPDT operation was used to conduct two experiments on a (monocrystalline germanium) workpiece. The first experiment was carried out using a diamond tool with a 1.5 mm nose radius, while the second experiment employed the use of a tool having a nose radius of 1.0 mm. A combination of machining parameters for each of the experimental runs were derived from a Box-Behnken method of design and the surface roughness was measured at each interval for both experiments with the aid of a Taylor Hopson PGI Dimension XL profilometer. Acoustic emission (AE) was also used as a quality sensing and tool-monitoring technique, to acquire signals and give indications of the expected surface roughness. Predictive models based on response surface methodology (RSM) and artificial neural networks (ANN), were developed for determining surface roughness. Optimisation was performed using RSM to determine the optimal set of machining factors, which results in optimal condition of the output response. Further investigations on the acquired signals were carried out using signal-processing techniques. Time-domain and time-frequency domain features acquired from the AE signals, together with the process parameters, were employed as input variables in the neural network design, having shown a good association with the surface roughness. ix Conclusively, it can be observed that the predictive model results and the experimental roughness measurements are in good agreement with each other. For accuracy and cost of computation, the RSM and ANN developed models for single-crystal germanium are compared using mean absolute error (MAE). , Thesis (M.Eng) -- Faculty of Engineering, the built environment & Information Technology, 2021
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Date Issued: 2021-04

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Isolation, propagation and rapid molecular detection of the Kalahari truffle, a mycorrhizal fungus occurring in South Africa

- Adeleke, Rasheed Adegbola

Authors: Adeleke, Rasheed Adegbola
Date: 2007 , 2013-04-03
Subjects: Truffles -- Kalahari Desert , Fungi -- Identification , Mycorrhizal fungi -- South Africa , Edible fungi -- South Africa , Mushroom culture -- South Africa , Fungi -- Cultures and culture media -- South Africa , Truffles -- South Africa , Truffles -- Lifecycles , Mycorrhizal fungi -- Lifecycles
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:3889 , http://hdl.handle.net/10962/d1002951 , Truffles -- Kalahari Desert , Fungi -- Identification , Mycorrhizal fungi -- South Africa , Edible fungi -- South Africa , Mushroom culture -- South Africa , Fungi -- Cultures and culture media -- South Africa , Truffles -- South Africa , Truffles -- Lifecycles , Mycorrhizal fungi -- Lifecycles
Description: Terfezia pfeilii is an edible mycorrhizal fungus that thrives in the Kalahari Desert of southern Africa. It is best known by desert dwellers for its flavour and as a source of nutrition. Although the genus Terfezia is generally regarded as being an ectomycorrhizal mycobiont, the exact mycorrhizal type formed by T. pfeilli and its' associated host plants remains uncertain. Discovery of the host plants for T. pfeilii would first be required in order to further investigate the life cycle and cultivation of this truffle. This study focussed on the isolation of mycelia from the ascocarp, optimising the growth conditions of the mycelial cultures, rapid molecular identification of T. pfeilii, investigation of potential helper bacteria and mycorrhizal synthesis experiments. T. pfeilii ascocarps were harvested from the Spitskop Nature Reserve in Upington, South Africa. Ascocarps were successfully identified using both morphological and molecular methods. Despite the delayed growth mostly caused by contaminating microorganisms, the isolation of T. pfeilii mycelia culture was successful. Molecular techniques were used to confirm the identity of the pure culture. Further studies were conducted on ways to improve the growth conditions of the mycelial culture on Fontana medium. An optimum temperature of 32°C, the addition of Bovine Serum Albumin as a nitrogen source and a pH of 7.5 significantly improved the growth of T. pfeilii in vitro. A rapid PeR-based molecular method was developed to speed up the identification of T. pfeilii. Specific primers that can exclusively amplify the ITS region of T. pfeilii were designed and used to identify both the ascocarps and the mycelial culture. The specificity of these primers was confirmed by their inability to amplify DNA from the isolates of contamining fungi obtained during the isolation process. Molecular comparison was made to confirm the reclassification of South African samples of T. pfeilii as Kalaharituber pfeilii as proposed by Ferdman et al.,(2005). However, in this study, the name T. pfeilii has been retained. A total of 17 bacterial isolates were obtained from the fruiting bodies of T. pfeaii and these were tested for stimulation of mycelial growth in vitro, indole production and phosphate solubilising capabilities. Bacterial isolates that showed potential to be Mycorrhization Helper Bacteria (MHB) were identified as Paenibacillus sp., Bacillus sp. and Rhizobium tropici. Selected plant seedlings were inoculated with T. pfeilii cultures or ascocarp slurry in order to re-establish the mycorrhizal association. After 8 months, light microscopy observations revealed an endomycorrhizal type association between Cynodon dactylon and T. pfeilii. This was confirmed with molecular analysis using specific T. pfeilii ITS primers. After 15 months, molecular methods confirmed Acacia erioloba as another host plant. These results have provided essential information paving the way for further investigation into the life cycle and biology of the Kalahari truffle. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
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Date Issued: 2007

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The factors that contribute to students’ positive perceptions towards service quality in selected off-campus residences in Nelson Mandela Bay

- Adeleke, Thobile

Authors: Adeleke, Thobile
Date: 2021-04
Subjects: SERVQUAL (Service quality framework) , Student housing -- Resident satisfaction -- South Africa , Consumer satisfaction -- South Africa
Language: English
Type: Master's theses , text
Identifier: http://hdl.handle.net/10948/50922 , vital:43172
Description: Post 1994 in South Africa there has been a notable increase in the number of students enrolled at different universities which offer student accommodation. Unfortunately, only 20% of the students can be accommodated in on-campus university accommodation, which results in most students seeking accommodation in off-campus student residences many of whom do not meet the quality requirements stipulated by the Department of Higher Education. This is what prompted this research study, whose aim was to investigate the perceptions of NMU students residing in off-campus residence, towards service quality. A literature review was conducted and focused on the service quality construct, delved into the definitions of services and quality and their benefits in all industries as well as within the student housing context. The different theoretical models used in the evaluation of service quality i.e., SERVQUAL, SERVPERF, the Gaps Model and Gronroos Model were discussed. A questionnaire based on the modified SERVQUAL tool was utilized in the evaluation of service quality levels in accredited NMU off-campus residences in Nelson Mandela Bay. Statistical evaluations were conducted on the five dimensions of SERVQUAL, namely, reliability; responsiveness; assurance; empathy and tangibles/physical attributes. The primary objective of this research was achieved, as the perceptions of students towards service quality in off-campus student accommodation were successfully measured using the SERVQUAL tool. Three service quality dimensions, namely, assurance, empathy and tangibles received positive assessments. On the other hand, the empirical research results clearly demonstrated two factors that scored low i.e., reliability and responsiveness, which reflects the respondents’ negative perceptions towards these two factors. Practical steps must be taken by off-campus residence management to ensure that the expectations versus perception service gap highlighted by the empirical findings of this study are addressed in order to keep their customers satisfied and remain competitive. Cronbach alpha coefficients above 0.80 were obtained for all the five variables, proving the SERVQUAL instrument’s internal consistency and reliability to be very good. , Thesis (MBA) -- Faculty of Business and Economic Science, Business Administration, 2021
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Date Issued: 2021-04

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Functionalized Ru(II) polypyridines and phthalocyanines: Potential dyes for dye-sensitized solar cells(DSSCs)

- Adeloye, Adewale Olufunsho https://orcid.org/0000-0003-1736-5738

Authors: Adeloye, Adewale Olufunsho https://orcid.org/0000-0003-1736-5738
Date: 2011-01
Subjects: Phthalocyanines , Dye-sensitized solar cells
Language: English
Type: Doctoral theses , text
Identifier: http://hdl.handle.net/10353/24365 , vital:62645
Description: This study describes the design, synthesis, characterization and preliminary investigation of the solar-to-electrical energy conversion efficiency of ruthenium(II) functionalized polypyridine and phthalocyanine complexes with extended π-conjugation. Polypyridinyl functionalized with anthracene, 2,3-dimethylacrylic acid and 1-methoxy-1-buten-3-yne were synthesized and characterized by infrared, UV-Vis, photoluminescence, 1H and 13C NMR and elemental analysis. The functionalized polypyridine molecules were used to synthesize various ruthenium(II) homoleptic/heteroleptic and/or heteronuclear complexes and their photophysical and electrochemical properties evaluated. The preliminary results of the solar-to-electrical conversion efficiencies of some synthesized Ru(II) polypyridyl complexes were presented in chapter 5. It was found out as expected that the ruthenium(II) polypyridine complexes containing either heteronuclear polypyridine ligands or their thiocyanate analogues of the types [Ru(L1)2L2(PF6)2], [RuL1(L2)2(PF6)2] and [RuL1L2(NCS)2], showed better photophysical properties (red-shifted metal-to-ligand charge-transfer (MLCT) transitions concomitant with enhanced molar extinction coefficients), luminescence and interesting electrochemical redox properties than those containing homonuclear ligand types [Ru(L1)3(PF6)2]. The ruthenium(II) anthracenyl functionalized phthalocyanine complexes which were obtained by electrophilic aromatic substitution reactions in the peripheral positions gave good solubility properties in various organic solvents and also showed interesting near infrared absorption and electroredox characteristics. Cyclic and square wave voltammetries of these complexes revealed major redox processes and the numbers of electron(s) transfer were determined by chronocoulometry. It was established that a mono- and/or multi-electronic transfer reactions can occur in the various ruthenium(II) complexes. The photophysical properties of some complexes showed them to be better and promising candidates in the design of chemosensors, organic light emitting diodes (OLEDs) and as photosensitizers, while their redox-active natures make them potential mediators in electron-transfer for various photochemical processes. However, due to low surface concentration and/or adsorption of some tested complexes on TiO2 semiconductor nanocrystalline particle, low currents were generated and the highest solar-to- electrical conversion efficiency recorded in this study was 0.10 percent. , Thesis (PhD) -- Faculty of Science and Agriculture, 2011
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Date Issued: 2011-01

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Functionalized Ru(II) polypyridines and phthalocyanines: Potential dyes for dye-sensitized solar cells(DSSCs)

- Adeloye, Adewale Olufunsho https://orcid.org/0000-0003-1736-5738

Authors: Adeloye, Adewale Olufunsho https://orcid.org/0000-0003-1736-5738
Date: 2011-01
Subjects: Phthalocyanines , Dye-sensitized solar cells
Language: English
Type: Doctoral theses , text
Identifier: http://hdl.handle.net/10353/24343 , vital:62638
Description: This study describes the design, synthesis, characterization and preliminary investigation of the solar-to-electrical energy conversion efficiency of ruthenium(II) functionalized polypyridine and phthalocyanine complexes with extended π-conjugation. Polypyridinyl functionalized with anthracene, 2,3-dimethylacrylic acid and 1-methoxy-1-buten-3-yne were synthesized and characterized by infrared, UV-Vis, photoluminescence, 1H and 13C NMR and elemental analysis. The functionalized polypyridine molecules were used to synthesize various ruthenium(II) homoleptic/heteroleptic and/or heteronuclear complexes and their photophysical and electrochemical properties evaluated. The preliminary results of the solar-to-electrical conversion efficiencies of some synthesized Ru(II) polypyridyl complexes were presented in chapter 5. It was found out as expected that the ruthenium(II) polypyridine complexes containing either heteronuclear polypyridine ligands or their thiocyanate analogues of the types [Ru(L1)2L2(PF6)2], [RuL1(L2)2(PF6)2] and [RuL1L2(NCS)2], showed better photophysical properties (red-shifted metal-to-ligand charge-transfer (MLCT) transitions concomitant with enhanced molar extinction coefficients), luminescence and interesting electrochemical redox properties than those containing homonuclear ligand types [Ru(L1)3(PF6)2]. The ruthenium(II) anthracenyl functionalized phthalocyanine complexes which were obtained by electrophilic aromatic substitution reactions in the peripheral positions gave good solubility properties in various organic solvents and also showed interesting near infrared absorption and electroredox characteristics. Cyclic and square wave voltammetries of these complexes revealed major redox processes and the numbers of electron(s) transfer were determined by chronocoulometry. It was established that a mono- and/or multi-electronic transfer reactions can occur in the various ruthenium(II) complexes. The photophysical properties of some complexes showed them to be better and promising candidates in the design of chemosensors, organic light emitting diodes (OLEDs) and as photosensitizers, while their redox-active natures make them potential mediators in electron-transfer for various photochemical processes. However, due to low surface concentration and/or adsorption of some tested complexes on TiO2 semiconductor nanocrystalline particle, low currents were generated and the highest solar-to-electrical conversion efficiency recorded in this study was 0.10 percent. , Thesis (PhD) -- Faculty of Science and Agriculture, 2011
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Date Issued: 2011-01

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