The photophysical properties of multi-functional quantum dots-magnetic nanoparticles—indium octacarboxyphthalocyanine nanocomposite
- Tshangana, Charmaine, Nyokong, Tebello
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189876 , vital:44942 , xlink:href="https://doi.org/10.1007/s10895-014-1497-6"
- Description: This work presents the development of a multifunctional hybrid nanoparticle made of L-glutathione capped quantum dots (GSH-CdSe@ZnS), amino functionalized Fe3O4 magnetic nanoparticles and indium octacarboxy phthalocyanine (ClInPc(COOH)8). In this work we investigate the photophysical properties of the individual components and the hybrid nanoparticle, in addition we study the energy transfer (Förster Resonance Energy Transfer (FRET)) in the complex. FRET efficiencies of ~48 % were obtained for energy transfer between the QDs (when alone or linked to MNPs). Both triplet yields and lifetimes of ClInPc(COOH)8 increase in the nanocomposite, with a decrease in fluorescence lifetime. The hybrid nanoparticle showed improved photophysical properties and as a result can be used in photodynamic therapy.
- Full Text:
- Date Issued: 2015
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189876 , vital:44942 , xlink:href="https://doi.org/10.1007/s10895-014-1497-6"
- Description: This work presents the development of a multifunctional hybrid nanoparticle made of L-glutathione capped quantum dots (GSH-CdSe@ZnS), amino functionalized Fe3O4 magnetic nanoparticles and indium octacarboxy phthalocyanine (ClInPc(COOH)8). In this work we investigate the photophysical properties of the individual components and the hybrid nanoparticle, in addition we study the energy transfer (Förster Resonance Energy Transfer (FRET)) in the complex. FRET efficiencies of ~48 % were obtained for energy transfer between the QDs (when alone or linked to MNPs). Both triplet yields and lifetimes of ClInPc(COOH)8 increase in the nanocomposite, with a decrease in fluorescence lifetime. The hybrid nanoparticle showed improved photophysical properties and as a result can be used in photodynamic therapy.
- Full Text:
- Date Issued: 2015
Wisdom as an aim of higher education
- Authors: Jones, Ward E
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275765 , vital:55077 , xlink:href="https://doi.org/10.1007/s10790-014-9443-z"
- Description: A central concern of theoretical speculation about education is the kind of epistemic states that education can and should aim to achieve. One such epistemic state, long neglected in both education theory and philosophy, is wisdom. Might wisdom be something that educators should aim for? And might it be something that their students can achieve? My answer will be a qualified yes.
- Full Text:
- Date Issued: 2015
- Authors: Jones, Ward E
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275765 , vital:55077 , xlink:href="https://doi.org/10.1007/s10790-014-9443-z"
- Description: A central concern of theoretical speculation about education is the kind of epistemic states that education can and should aim to achieve. One such epistemic state, long neglected in both education theory and philosophy, is wisdom. Might wisdom be something that educators should aim for? And might it be something that their students can achieve? My answer will be a qualified yes.
- Full Text:
- Date Issued: 2015
(Ferrocenylpyrazolyl) zinc (II) benzoates as catalysts for the ring opening polymerization of ε-caprolactone
- Obuah, Collins, Lochee, Yemanlall, Jordaan, Johan H L, Otto, Daniel P, Nyokong, Tebello, Darkwa, James
- Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
- Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
- Full Text:
- Date Issued: 2015
- Authors: Obuah, Collins , Lochee, Yemanlall , Jordaan, Johan H L , Otto, Daniel P , Nyokong, Tebello , Darkwa, James
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189515 , vital:44853 , xlink:href="https://doi.org/10.1016/j.poly.2015.02.007"
- Description: The reaction of Zn(OAc)2 and C6H5COOH or 3,5-NO2-C6H3COOH with 3-ferrocenylpyrazolyl-methylenepyridine (L1), 3-ferrocenyl-5-methylpyrazolyl-methylenepyridine (L2), 3-ferrocenylpyrazolyl-ethylamine (L3) and 3-ferrocenyl-5-pyrazolyl-ethylamine (L4) afford the corresponding complexes [Zn(C6H5COO)2(L1)] (1), [Zn(C6H5COO)2(L2)] (2), [Zn(3,5-NO2-C6H3COO)2(L1)] (3), [Zn(3,5-NO2-C6H3 COO)2(L2)] (4), [Zn(C6H5COO)2(L3)] (5), [Zn(C6H5COO)2(L4)] (6), [Zn(3,5-NO2-C6H3COO)2(L3)] (7) and [Zn(3,5-NO2-C6H3COO)2(L4)] (8). These complexes behave as catalysts for the ring opening polymerization of e-caprolactone to produce polymers with molecular weight that range from 1480 to 7080 g mol1 and exhibited moderate to broad PDIs. Evidence of these complexes acting as catalysts was obtained from both the polymerization data and kinetic studies. The polymerization data show that variation of the [CL]/[C] from 100 to 800 produced PCL with relatively the same molecular weight indicative of a catalyst behavior. The appearance of induction period in kinetic plots strengthens the fact that these complexes are catalysts rather than initiators. MALDI-TOF MS and 1 H NMR data show di-hydroxy end groups, which support the coordination mechanism rather than insertion mechanism. To understand the broad PDIs obtained for some of the polymer, the electronic properties of the zinc complexes were investigated using cyclic voltammetry. The results show that the zinc complexes containing amine based ligands are highly electrophilic therefore making them unstable, hence the broad PDIs observed for zinc complexes containing amine based ligands. Among the eight complexes investigated, complex 7 is the most active catalyst with kp value of 1.18 107 h1 mol1 at 110 C.
- Full Text:
- Date Issued: 2015
Unravelling the myths about unplanned pregnancy among female students at University of Fort Hare East London Campus, South Africa
- Authors: Chukwunyere , Amadi P
- Date: 2015
- Subjects: Unwanted pregnancy , Women college students , College students
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25415 , vital:64237
- Description: This research study examined: 1. the attitudes and perceptions of female university students towards unplanned pregnancies, their (pregnancies’) associated influences and their social economic consequences on the participants and their family. 2. The level of knowledge, the sources thereof, and the girls’ attitudes and perceptions toward contraception, abortion and their actual use as possible barriers in the prevention of unplanned pregnancies. 3. The possible interventions in curbing the phenomenon of unplanned pregnancies. Data for the study was gathered through in-depth-interviews with ten female undergraduate students at the University of Fort Hare in East London campus, who had the experience of unplanned pregnancy while studying. Selection of participants was done through snowball sampling. A number of factors responsible for the unplanned pregnancy are revealed, including: Inadequate and inconsistent use of contraceptives, ignorance about contraception or rejection of contraceptive use due to religious beliefs. Influential factors regarding unplanned child bearing include: The role of the mother and the boyfriend, traditional and religious beliefs, and the desire for child bearing and motherhood. Although the majority of the girls are knowledgeable about contraception, and their right to abortion, a number of barriers hinder them from putting this knowledge into practical use. Some of the most highlighted consequences of unplanned/unwanted pregnancy are the financial burden on the family and loss of study time. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2015
- Full Text:
- Date Issued: 2015
- Authors: Chukwunyere , Amadi P
- Date: 2015
- Subjects: Unwanted pregnancy , Women college students , College students
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10353/25415 , vital:64237
- Description: This research study examined: 1. the attitudes and perceptions of female university students towards unplanned pregnancies, their (pregnancies’) associated influences and their social economic consequences on the participants and their family. 2. The level of knowledge, the sources thereof, and the girls’ attitudes and perceptions toward contraception, abortion and their actual use as possible barriers in the prevention of unplanned pregnancies. 3. The possible interventions in curbing the phenomenon of unplanned pregnancies. Data for the study was gathered through in-depth-interviews with ten female undergraduate students at the University of Fort Hare in East London campus, who had the experience of unplanned pregnancy while studying. Selection of participants was done through snowball sampling. A number of factors responsible for the unplanned pregnancy are revealed, including: Inadequate and inconsistent use of contraceptives, ignorance about contraception or rejection of contraceptive use due to religious beliefs. Influential factors regarding unplanned child bearing include: The role of the mother and the boyfriend, traditional and religious beliefs, and the desire for child bearing and motherhood. Although the majority of the girls are knowledgeable about contraception, and their right to abortion, a number of barriers hinder them from putting this knowledge into practical use. Some of the most highlighted consequences of unplanned/unwanted pregnancy are the financial burden on the family and loss of study time. , Thesis (MSoc) -- Faculty of Social Sciences and Humanities, 2015
- Full Text:
- Date Issued: 2015
Visible light transformation of Rhodamine 6G using tetracarbazole zinc phthalocyanine when embedded in electrospun fibers and in the presence of ZnO and Ag particles
- Khoza, Phindile, Nyokong, Tebello
- Authors: Khoza, Phindile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189456 , vital:44848 , xlink:href="https://doi.org/10.1080/00958972.2015.1013944"
- Description: Herein, we report the photocatalytic transformation of Rhodamine 6G (Rh 6G) using tetracarbazole zinc phthalocyanine (TCbZnPc) when alone or when conjugated with ZnO macroparticles (ZnOMPs) and silver nanoparticles (AgNPs), represented as TCbZnPc–ZnOMPs and TCbZnPc–AgNPs, respectively. The photocatalysts were supported onto electrospun polystyrene fibers. The efficiency of TCbZnPc was improved by the presence of both ZnOMPs and AgNPs. HPLC equipped with UV–vis was used to study phototransformation products. The mechanism of transformation was via the N-de-ethylation of Rh 6G.
- Full Text:
- Date Issued: 2015
- Authors: Khoza, Phindile , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189456 , vital:44848 , xlink:href="https://doi.org/10.1080/00958972.2015.1013944"
- Description: Herein, we report the photocatalytic transformation of Rhodamine 6G (Rh 6G) using tetracarbazole zinc phthalocyanine (TCbZnPc) when alone or when conjugated with ZnO macroparticles (ZnOMPs) and silver nanoparticles (AgNPs), represented as TCbZnPc–ZnOMPs and TCbZnPc–AgNPs, respectively. The photocatalysts were supported onto electrospun polystyrene fibers. The efficiency of TCbZnPc was improved by the presence of both ZnOMPs and AgNPs. HPLC equipped with UV–vis was used to study phototransformation products. The mechanism of transformation was via the N-de-ethylation of Rh 6G.
- Full Text:
- Date Issued: 2015
Educators and learners perceptions on english first additional language speakers use of english as medium of instruction
- Authors: Nqoma, Lungiswa
- Date: 2015
- Subjects: English language -- Study and teaching , English language
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24934 , vital:63678
- Description: This study investigates Educators‟ and learners‟ perceptions on English first additional language speakers‟ use of English as medium of instruction in two primary schools in the East London District. The study made use of a qualitative research method which includes interviews, observation and document analysis (learners‟ books). The uncovered data is analyzed against the background of the socio-economic and historical factors that led to this medium of instruction using content analysis (CA). After the apartheid regime in 1994 and the formation of a new government in 1996, the South African Constitution declared 11 languages in an attempt to encourage multilingualism in the country with each province having its provincial language policy. In the Eastern Cape where the study is conducted the language policy recognizes Xhosa, English, and Afrikaans as the official languages with English as the medium of instruction especially at the intermediate phase. The theoretical and conceptual framework for the study is provided by studies on language policy and planning, English as an international language, and Language as a mediating tool. The findings of the study indicate the crucial role that language of instruction plays in teaching and learning. However, challenges arise when the language of instruction is not the mother tongue. The study indicates dissatisfaction in the use of EMOI as a result of inadequate proficiency in the language of instruction, school environment, lack of resources; and lack of parental support. As a result of the above, some educators resorted to code switching when teaching. Hence, the study sheds light on EFAL learner‟s perspective on both comprehension and the level of educator‟s English skills and whether there is a connection between these two aspects. This resulted to conceivable methods that could be used to improve learner performance, teaching and learning methods and the efficiency of East London District support system. , Thesis (MEd) -- Faculty of Education, 2015
- Full Text:
- Date Issued: 2015
- Authors: Nqoma, Lungiswa
- Date: 2015
- Subjects: English language -- Study and teaching , English language
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/24934 , vital:63678
- Description: This study investigates Educators‟ and learners‟ perceptions on English first additional language speakers‟ use of English as medium of instruction in two primary schools in the East London District. The study made use of a qualitative research method which includes interviews, observation and document analysis (learners‟ books). The uncovered data is analyzed against the background of the socio-economic and historical factors that led to this medium of instruction using content analysis (CA). After the apartheid regime in 1994 and the formation of a new government in 1996, the South African Constitution declared 11 languages in an attempt to encourage multilingualism in the country with each province having its provincial language policy. In the Eastern Cape where the study is conducted the language policy recognizes Xhosa, English, and Afrikaans as the official languages with English as the medium of instruction especially at the intermediate phase. The theoretical and conceptual framework for the study is provided by studies on language policy and planning, English as an international language, and Language as a mediating tool. The findings of the study indicate the crucial role that language of instruction plays in teaching and learning. However, challenges arise when the language of instruction is not the mother tongue. The study indicates dissatisfaction in the use of EMOI as a result of inadequate proficiency in the language of instruction, school environment, lack of resources; and lack of parental support. As a result of the above, some educators resorted to code switching when teaching. Hence, the study sheds light on EFAL learner‟s perspective on both comprehension and the level of educator‟s English skills and whether there is a connection between these two aspects. This resulted to conceivable methods that could be used to improve learner performance, teaching and learning methods and the efficiency of East London District support system. , Thesis (MEd) -- Faculty of Education, 2015
- Full Text:
- Date Issued: 2015
Optical properties of water-soluble L-cysteine-capped alloyed CdSeS quantum dot passivated with ZnSeTe and ZnSeTe/ZnS shells
- 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/10962/193609 , vital:45352 , xlink:href="https://doi.org/10.1016/j.optmat.2015.05.024"
- Description: Alloyed quantum dots (QDs) passivated with shell materials have valuable optical characteristics suitable for a wide array of applications. In this work, alloyed ternary CdSeS QDs passivated with ZnSeTe and ZnSeTe/ZnS shells have been synthesized via a hot-injection method and a ligand exchange reaction employing L-cysteine as a thiol ligand has been used to obtain these water-soluble nanocrystals for the first time. The photoluminescence (PL) quantum yield (QY) of alloyed L-cysteine-capped CdSeS was 71.2% but decreased significantly to 5.2% upon passivation with a ZnSeTe shell. The red shift in PL emission of the CdSeS/ZnSeTe QDs was attributed to be strain-induced whilst a lattice-induced process likely created defect states in the core/shell interface hence contributing to the decline in the PL QY. Nonetheless, the fluorescence stability of CdSeS/ZnSeTe QDs in aqueous solution was unperturbed. Further passivation with a ZnS shell (CdSeS/ZnSeTe/ZnS) improved the PL QY to a value of 58.7% and thus indicates that the defect state in the QDs core/shell/shell structure was reduced. PL lifetime exciton measurements indicated that the rates of decay of the QDs influenced their photophysical properties.
- Full Text:
- Date Issued: 2015
- 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/10962/193609 , vital:45352 , xlink:href="https://doi.org/10.1016/j.optmat.2015.05.024"
- Description: Alloyed quantum dots (QDs) passivated with shell materials have valuable optical characteristics suitable for a wide array of applications. In this work, alloyed ternary CdSeS QDs passivated with ZnSeTe and ZnSeTe/ZnS shells have been synthesized via a hot-injection method and a ligand exchange reaction employing L-cysteine as a thiol ligand has been used to obtain these water-soluble nanocrystals for the first time. The photoluminescence (PL) quantum yield (QY) of alloyed L-cysteine-capped CdSeS was 71.2% but decreased significantly to 5.2% upon passivation with a ZnSeTe shell. The red shift in PL emission of the CdSeS/ZnSeTe QDs was attributed to be strain-induced whilst a lattice-induced process likely created defect states in the core/shell interface hence contributing to the decline in the PL QY. Nonetheless, the fluorescence stability of CdSeS/ZnSeTe QDs in aqueous solution was unperturbed. Further passivation with a ZnS shell (CdSeS/ZnSeTe/ZnS) improved the PL QY to a value of 58.7% and thus indicates that the defect state in the QDs core/shell/shell structure was reduced. PL lifetime exciton measurements indicated that the rates of decay of the QDs influenced their photophysical properties.
- Full Text:
- Date Issued: 2015
Evaluation of knowledge and practices of nurses with regard to prevention of nosocomial infection in the intensive care units of Eastern Cape Province
- Mlenzana, Nosiphiwo Priscilla
- Authors: Mlenzana, Nosiphiwo Priscilla
- Date: 2015
- Subjects: Nosocomial infections http://id.loc.gov/authorities/subjects/sh85092770 , Cross infection--Prevention http://id.loc.gov/authorities/subjects/sh2009122612 , Infection http://id.loc.gov/authorities/subjects/sh85066076
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19639 , vital:43154
- Description: Aim: To determine the level of knowledge and practice of the nurses in the prevention and control of nosocomial infection in the intensive care units and make recommendations aiming at bridging the gap identified. In this study, the level of knowledge and practice of nurses in the intensive care units was described and its relationship with the demographic characteristics was examined utilising a quantitative approach. A quantitative descriptive design was used to examine and describe knowledge and practices of intensive care nurses with regards to prevention and control of nosocomial infection. One hundred and thirty (130) nurses participated in the study taken from the intensive care units of the five (5) state hospitals of the Eastern Cape Province. A self-designed questionnaire with close-ended questions was utilised comprising of dichotomous questions, with ‘yes’ or ‘no’ measuring knowledge nurses have and a Likert scale that measured knowledge with regards to clinical practice utilised in the prevention and control of nosocomial infections. The following ethical considerations were addressed by the study: ethical clearance, permission to conduct the study, informed consent from participants, anonymity and confidentiality and respect of individual autonomy. Findings: The respondents showed encouraging agreement with the different practices that should be followed in order to prevent spreading of nosocomial infections in their units. This knowledge suggests that the problem of infection control in ICUs may be related to the individual characteristics of the profession as opposed to being institutional. Limitations: Not all the intensive care units of the Eastern Cape hospitals were included due to challenges of time, finance and geographic factors. Recommendations: The following recommendations were made: Orientation programme to all new staff coming into the ICUs including infection control policies and guidelines; Involvement of the ICU staff in the development of infection control policies so as to ensure ownership and ultimate compliance; The employer must ensure that all resources for infection control and prevention are available and accessible to the health care workers at all times to ensure compliance. , Thesis (MCur) -- University of Fort Hare, 2015
- Full Text:
- Date Issued: 2015
- Authors: Mlenzana, Nosiphiwo Priscilla
- Date: 2015
- Subjects: Nosocomial infections http://id.loc.gov/authorities/subjects/sh85092770 , Cross infection--Prevention http://id.loc.gov/authorities/subjects/sh2009122612 , Infection http://id.loc.gov/authorities/subjects/sh85066076
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/19639 , vital:43154
- Description: Aim: To determine the level of knowledge and practice of the nurses in the prevention and control of nosocomial infection in the intensive care units and make recommendations aiming at bridging the gap identified. In this study, the level of knowledge and practice of nurses in the intensive care units was described and its relationship with the demographic characteristics was examined utilising a quantitative approach. A quantitative descriptive design was used to examine and describe knowledge and practices of intensive care nurses with regards to prevention and control of nosocomial infection. One hundred and thirty (130) nurses participated in the study taken from the intensive care units of the five (5) state hospitals of the Eastern Cape Province. A self-designed questionnaire with close-ended questions was utilised comprising of dichotomous questions, with ‘yes’ or ‘no’ measuring knowledge nurses have and a Likert scale that measured knowledge with regards to clinical practice utilised in the prevention and control of nosocomial infections. The following ethical considerations were addressed by the study: ethical clearance, permission to conduct the study, informed consent from participants, anonymity and confidentiality and respect of individual autonomy. Findings: The respondents showed encouraging agreement with the different practices that should be followed in order to prevent spreading of nosocomial infections in their units. This knowledge suggests that the problem of infection control in ICUs may be related to the individual characteristics of the profession as opposed to being institutional. Limitations: Not all the intensive care units of the Eastern Cape hospitals were included due to challenges of time, finance and geographic factors. Recommendations: The following recommendations were made: Orientation programme to all new staff coming into the ICUs including infection control policies and guidelines; Involvement of the ICU staff in the development of infection control policies so as to ensure ownership and ultimate compliance; The employer must ensure that all resources for infection control and prevention are available and accessible to the health care workers at all times to ensure compliance. , Thesis (MCur) -- University of Fort Hare, 2015
- Full Text:
- Date Issued: 2015
The influence of livelihood dependency, local ecological knowledge and market proximity on the ecological impacts of harvesting non-timber forest products
- Steele, Melita Z, Shackleton, Charlie M, Shaanker, Ramanan U, Ganeshaiah, Kotiganahalli N, Radloff, Sarah E
- Authors: Steele, Melita Z , Shackleton, Charlie M , Shaanker, Ramanan U , Ganeshaiah, Kotiganahalli N , Radloff, Sarah E
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180908 , vital:43669 , xlink:href="https://doi.org/10.1016/j.forpol.2014.07.011"
- Description: It is well established that non-timber forest products make significant contributions to rural incomes throughout most of the developing world. NTFP use frequently raises concerns about the sustainability of, or ecological impacts associated with, NTFP harvesting, as well as local contextual factors which may limit or reduce the impacts. Here we test the conceptual model first advanced by Uma Shaanker et al. (2004) relating to the factors that may limit or exacerbate the ecological impacts associated with NTFP harvesting. These were the extent of local dependence on NTFPs, the degree of marketing and the level of local ecological knowledge. Data were collected via household questionnaires and ecological surveys of woody plants from eight villages throughout South Africa. We found no significant relationships between measures of ecological impact with local ecological knowledge or market proximity and engagement. There was a strong positive relationship between ecological impacts and NTFP dependency as indexed through mean annual direct-use value for NTFPs. This indicates that the higher the dependency and demand for NTFPs, the greater is the possibility of high impacts to the local environment. However, other contextual drivers not included in the original Uma Shaanker et al. (2004) model may also play a role, particularly the strength of local resource governance institutions.
- Full Text: false
- Date Issued: 2015
- Authors: Steele, Melita Z , Shackleton, Charlie M , Shaanker, Ramanan U , Ganeshaiah, Kotiganahalli N , Radloff, Sarah E
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180908 , vital:43669 , xlink:href="https://doi.org/10.1016/j.forpol.2014.07.011"
- Description: It is well established that non-timber forest products make significant contributions to rural incomes throughout most of the developing world. NTFP use frequently raises concerns about the sustainability of, or ecological impacts associated with, NTFP harvesting, as well as local contextual factors which may limit or reduce the impacts. Here we test the conceptual model first advanced by Uma Shaanker et al. (2004) relating to the factors that may limit or exacerbate the ecological impacts associated with NTFP harvesting. These were the extent of local dependence on NTFPs, the degree of marketing and the level of local ecological knowledge. Data were collected via household questionnaires and ecological surveys of woody plants from eight villages throughout South Africa. We found no significant relationships between measures of ecological impact with local ecological knowledge or market proximity and engagement. There was a strong positive relationship between ecological impacts and NTFP dependency as indexed through mean annual direct-use value for NTFPs. This indicates that the higher the dependency and demand for NTFPs, the greater is the possibility of high impacts to the local environment. However, other contextual drivers not included in the original Uma Shaanker et al. (2004) model may also play a role, particularly the strength of local resource governance institutions.
- Full Text: false
- Date Issued: 2015
Synthesis and photophysical properties of nanocomposites of aluminum tetrasulfonated phthalocyanine covalently linked to glutathione capped CdTe/CdS/ZnS quantum dots
- Oluwole, David O, Britton, Jonathan, Mashazi, Philani N, Nyokong, Tebello
- Authors: Oluwole, David O , Britton, Jonathan , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241379 , vital:50934 , xlink:href="https://doi.org/10.1016/j.synthmet.2015.04.015"
- Description: Aluminum tetrasulfonated phthalocyanine (ClAlTSPc) was covalently linked with different sizes of glutathione capped CdTe/CdS/ZnS quantum dots (QDs). The photophysical and Förster resonance energy transfer (FRET) properties of the nanoconjugates were investigated. The CdTe/CdS/ZnS(6.3) nanocomposite showed the highest enhancement in its photophysical properties while (CdTe/CdS/ZnS(3.2) nanocomposite showed the least. Highest FRET efficiency was observed in the linked CdTe/CdS/ZnS(6.3) nanocomposites at 93%. Hence, the combination of CdTe/CdS/ZnS with ClAlTSPc exhibited excellent photophysical properties.
- Full Text:
- Date Issued: 2015
- Authors: Oluwole, David O , Britton, Jonathan , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241379 , vital:50934 , xlink:href="https://doi.org/10.1016/j.synthmet.2015.04.015"
- Description: Aluminum tetrasulfonated phthalocyanine (ClAlTSPc) was covalently linked with different sizes of glutathione capped CdTe/CdS/ZnS quantum dots (QDs). The photophysical and Förster resonance energy transfer (FRET) properties of the nanoconjugates were investigated. The CdTe/CdS/ZnS(6.3) nanocomposite showed the highest enhancement in its photophysical properties while (CdTe/CdS/ZnS(3.2) nanocomposite showed the least. Highest FRET efficiency was observed in the linked CdTe/CdS/ZnS(6.3) nanocomposites at 93%. Hence, the combination of CdTe/CdS/ZnS with ClAlTSPc exhibited excellent photophysical properties.
- Full Text:
- Date Issued: 2015
Book Review Growing the next generation of researchers: A handbook for emerging researchers and their mentors, Holness, L
- Motshoane, Puleng, Muthama, Evelyn, McKenna, Sioux
- Authors: Motshoane, Puleng , Muthama, Evelyn , McKenna, Sioux
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187205 , vital:44579 , xlink:href="https://doi.org/10.14426/cristal.v3i2.56"
- Description: South Africa urgently needs more researchers (NRF, 2008; NDP, 2011). We also need a transformation in the demographics of our researchers. One indicator of this is that currently only 14% of university professors are black African, and only 2% are black African females (DHET, 2012). The Staffing South Africa's Universities Framework includes a number of initiatives to drive the process of growing the next generation of academics. For example, the nGAP project has inserted 125 new posts into the higher education system in 2015, with more to follow. This project allows for new academics to undertake postgraduate study and develop as teachers and researchers through mentorship, a reduced teaching load and so on.
- Full Text:
- Date Issued: 2015
- Authors: Motshoane, Puleng , Muthama, Evelyn , McKenna, Sioux
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187205 , vital:44579 , xlink:href="https://doi.org/10.14426/cristal.v3i2.56"
- Description: South Africa urgently needs more researchers (NRF, 2008; NDP, 2011). We also need a transformation in the demographics of our researchers. One indicator of this is that currently only 14% of university professors are black African, and only 2% are black African females (DHET, 2012). The Staffing South Africa's Universities Framework includes a number of initiatives to drive the process of growing the next generation of academics. For example, the nGAP project has inserted 125 new posts into the higher education system in 2015, with more to follow. This project allows for new academics to undertake postgraduate study and develop as teachers and researchers through mentorship, a reduced teaching load and so on.
- Full Text:
- Date Issued: 2015
Synthesis and characterization of Na (Y, Gd) F4 upconversion nanoparticles and an investigation of their effects on the photophysical properties of an unsubstituted tetrathiophenoxy phthalocyanine
- Taylor, Jessica M, Litwinski, Christian, Nyokong, Tebello, Antunes, Edith M
- Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241437 , vital:50939 , xlink:href="https://doi.org/10.1007/s11051-015-2889-5"
- Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs.
- Full Text:
- Date Issued: 2015
- Authors: Taylor, Jessica M , Litwinski, Christian , Nyokong, Tebello , Antunes, Edith M
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/241437 , vital:50939 , xlink:href="https://doi.org/10.1007/s11051-015-2889-5"
- Description: Sphere- and star-shaped Na(Y,Gd)F4:Yb/Er(Tm)upconversion nanoparticles (UCNP) were successfully synthesized utilizing a methanol-assisted thermal decomposition approach and their spectroscopic (absorption, emission and luminescence lifetime) properties fully characterized. The factors affecting the size and shape of the UCNPs were studied and discussed in detail. The size of the nanoparticles was determined using TEM primarily and found to be approximately 19 and 30 nm for the Er and Tm spheres, respectively, while the Er and Tm “stars” were found to be much larger with sizes ranging from 110 to 240 nm, respectively (as determined along the width of the nanoparticle). In addition, their influence on the spectroscopic properties of an unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) was investigated. The UCNP were found to produce characteristic upconversion luminescence emissions in the blue, green, red and NIR regions. Simple mixing with an H2Pc in toluene was found to exert no obvious changes in the spectroscopic properties of the Pc, although a considerable increase in the radiative lifetimes is observed for the Pc in the presence of the UCNPs. The singlet oxygen generation mediated by the red light excitation of the H2Pc mixed with UCNP was found to decrease in the presence of the NPs.
- Full Text:
- Date Issued: 2015
Establishment of human OCT4 as a putative HSP90 client protein: a case for HSP90 chaperoning pluripotency
- Authors: Sterrenberg, Jason Neville
- Date: 2015
- Subjects: Induced pluripotent stem cells , Heat shock proteins , Stem cells , Transcription factors , Molecular chaperones
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194010 , vital:45415 , 10.21504/10962/194010
- Description: The therapeutic potential of stem cells is already being harnessed in clinical trails. Of even greater therapeutic potential has been the discovery of mechanisms to reprogram differentiated cells into a pluripotent stem cell-like state known as induced pluripotent stem cells (iPSCs). Stem cell nature is governed and maintained by a hierarchy of transcription factors, the apex of which is OCT4. Although much research has elucidated the transcriptional regulation of OCT4, OCT4 regulated gene expression profiles and OCT4 transcriptional activation mechanisms in both stem cell biology and cellular reprogramming to iPSCs, the fundamental biochemistry surrounding the OCT4 transcription factor remains largely unknown. In order to analyze the biochemical relationship between HSP90 and human OCT4 we developed an exogenous active human OCT4 expression model with human OCT4 under transcriptional control of a constitutive promoter. We identified the direct interaction between HSP90 and human OCT4 despite the fact that the proteins predominantly display differential subcellular localizations. We show that HSP90 inhibition resulted in degradation of human OCT4 via the ubiquitin proteasome degradation pathway. As human OCT4 and HSP90 did not interact in the nucleus, we suggest that HSP90 functions in the cytoplasmic stabilization of human OCT4. Our analysis suggests HSP90 inhibition inhibits the transcriptional activity of human OCT4 dimers without affecting monomeric OCT4 activity. Additionally our data suggests that the HSP90 and human OCT4 complex is modulated by phosphorylation events either promoting or abrogating the interaction between HSP90 and human OCT4. Our data suggest that human OCT4 displays the characteristics describing HSP90 client proteins, therefore we identify human OCT4 as a putative HSP90 client protein. The regulation of the transcription factor OCT4 by HSP90 provides fundamental insights into the complex biochemistry of stem cell biology. This may also be suggestive that HSP90 not only regulates stem cell biology by maintaining routine cellular homeostasis but additionally through the direct regulation of pluripotency factors. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2015
- Full Text:
- Date Issued: 2015
- Authors: Sterrenberg, Jason Neville
- Date: 2015
- Subjects: Induced pluripotent stem cells , Heat shock proteins , Stem cells , Transcription factors , Molecular chaperones
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/194010 , vital:45415 , 10.21504/10962/194010
- Description: The therapeutic potential of stem cells is already being harnessed in clinical trails. Of even greater therapeutic potential has been the discovery of mechanisms to reprogram differentiated cells into a pluripotent stem cell-like state known as induced pluripotent stem cells (iPSCs). Stem cell nature is governed and maintained by a hierarchy of transcription factors, the apex of which is OCT4. Although much research has elucidated the transcriptional regulation of OCT4, OCT4 regulated gene expression profiles and OCT4 transcriptional activation mechanisms in both stem cell biology and cellular reprogramming to iPSCs, the fundamental biochemistry surrounding the OCT4 transcription factor remains largely unknown. In order to analyze the biochemical relationship between HSP90 and human OCT4 we developed an exogenous active human OCT4 expression model with human OCT4 under transcriptional control of a constitutive promoter. We identified the direct interaction between HSP90 and human OCT4 despite the fact that the proteins predominantly display differential subcellular localizations. We show that HSP90 inhibition resulted in degradation of human OCT4 via the ubiquitin proteasome degradation pathway. As human OCT4 and HSP90 did not interact in the nucleus, we suggest that HSP90 functions in the cytoplasmic stabilization of human OCT4. Our analysis suggests HSP90 inhibition inhibits the transcriptional activity of human OCT4 dimers without affecting monomeric OCT4 activity. Additionally our data suggests that the HSP90 and human OCT4 complex is modulated by phosphorylation events either promoting or abrogating the interaction between HSP90 and human OCT4. Our data suggest that human OCT4 displays the characteristics describing HSP90 client proteins, therefore we identify human OCT4 as a putative HSP90 client protein. The regulation of the transcription factor OCT4 by HSP90 provides fundamental insights into the complex biochemistry of stem cell biology. This may also be suggestive that HSP90 not only regulates stem cell biology by maintaining routine cellular homeostasis but additionally through the direct regulation of pluripotency factors. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2015
- Full Text:
- Date Issued: 2015
The reform of world order?: BRICS in an Interpolar world
- Authors: Phyllis, Yvonne
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193520 , vital:45339
- Description: International relations has recently seen new developments which are unpredictable and in their infant stage. The causes of these developments are plentiful, the consequences stemming from waning unipolarity to the emergence of new fora creating their own spaces. Whatever the case, international relations is not as it was in the period just after the Cold War. As a result, the terms of global governance established after 1990 have come under serious scrutiny. This transition has the makings of a new world order, an interpolar world order. This study asserts that we no longer live in a unipolar world, nor do we live in a world which can only be described as multipolar. It makes the argument that although multipolarity is a crucial element of the world, it only offers a partial description of today’s order. The study asserts that it is interpolarity which is closest in accounting for today’s world. Not only does it describe the world as multipolar, it also describes it as interdependent. To this end, the study provides a detailed account of what is meant by an interpolar world order and how differently it explains international events. It also provides an account of factors which can develop in an interpolar world. One of these includes allowing room for emerging powers to create their own spaces in efforts of avoiding co-option while continuing to realise the importance of operating within a context of continuity. This means that emerging countries create their own spaces but they also realise the importance of working with already established regimes such as the G20. BRICS (Brazil, Russia, India, China and South Africa) is used as a case study to indicate one of the new developments afforded by an interpolar order-the emergence of new fora. The study asserts that although BRICS is rife with internal dissimilarities, it has indicated some degree of political will in one aspect; that is; advocating for the reform of the terms of global governance, advocating for more representative forms of global governance. The study thus explores factors of a world whose contours are gradually changing but which are unpredictable and in flux. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2015
- Full Text:
- Date Issued: 2015
- Authors: Phyllis, Yvonne
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193520 , vital:45339
- Description: International relations has recently seen new developments which are unpredictable and in their infant stage. The causes of these developments are plentiful, the consequences stemming from waning unipolarity to the emergence of new fora creating their own spaces. Whatever the case, international relations is not as it was in the period just after the Cold War. As a result, the terms of global governance established after 1990 have come under serious scrutiny. This transition has the makings of a new world order, an interpolar world order. This study asserts that we no longer live in a unipolar world, nor do we live in a world which can only be described as multipolar. It makes the argument that although multipolarity is a crucial element of the world, it only offers a partial description of today’s order. The study asserts that it is interpolarity which is closest in accounting for today’s world. Not only does it describe the world as multipolar, it also describes it as interdependent. To this end, the study provides a detailed account of what is meant by an interpolar world order and how differently it explains international events. It also provides an account of factors which can develop in an interpolar world. One of these includes allowing room for emerging powers to create their own spaces in efforts of avoiding co-option while continuing to realise the importance of operating within a context of continuity. This means that emerging countries create their own spaces but they also realise the importance of working with already established regimes such as the G20. BRICS (Brazil, Russia, India, China and South Africa) is used as a case study to indicate one of the new developments afforded by an interpolar order-the emergence of new fora. The study asserts that although BRICS is rife with internal dissimilarities, it has indicated some degree of political will in one aspect; that is; advocating for the reform of the terms of global governance, advocating for more representative forms of global governance. The study thus explores factors of a world whose contours are gradually changing but which are unpredictable and in flux. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2015
- Full Text:
- Date Issued: 2015
Physicochemical behavior of nanohybrids of mono and tetra substituted carboxyphenoxy phthalocyanine covalently linked to GSH–CdTe/CdS/ZnS quantum dots
- Oluwole, David O, Nyokong, Tebello
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189480 , vital:44850 , xlink:href="https://doi.org/10.1016/j.poly.2014.10.024"
- Description: Zinc monocarboxyphenoxy and tetracarboxyphenoxy phthalocyanines were covalently linked with three different sizes of glutathione capped core/shell/shell {CdTe/CdS/ZnS(4.2), CdTe/CdS/ZnS(5.1) and CdTe/CdS/ZnS(6.7)}; a core shell {CdTe/CdS(3.1)} and core {CdTe(2.4)} quantum dots. The physicochemical behavior and Förster resonance energy transfer (FRET) processes of the nanohybrids were investigated. The highest FRET efficiency was observed with CdTe/CdS/ZnS(6.7) nanohybrids with 98% and the least efficiency was observed with CdTe(2.4) nanohybrids with 85%. The CdTe/CdS/ZnS(6.7) also showed the best physicochemical behavior. These good physicochemical properties make the synthesized nanohybrids viable photosensitizers.
- Full Text:
- Date Issued: 2015
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189480 , vital:44850 , xlink:href="https://doi.org/10.1016/j.poly.2014.10.024"
- Description: Zinc monocarboxyphenoxy and tetracarboxyphenoxy phthalocyanines were covalently linked with three different sizes of glutathione capped core/shell/shell {CdTe/CdS/ZnS(4.2), CdTe/CdS/ZnS(5.1) and CdTe/CdS/ZnS(6.7)}; a core shell {CdTe/CdS(3.1)} and core {CdTe(2.4)} quantum dots. The physicochemical behavior and Förster resonance energy transfer (FRET) processes of the nanohybrids were investigated. The highest FRET efficiency was observed with CdTe/CdS/ZnS(6.7) nanohybrids with 98% and the least efficiency was observed with CdTe(2.4) nanohybrids with 85%. The CdTe/CdS/ZnS(6.7) also showed the best physicochemical behavior. These good physicochemical properties make the synthesized nanohybrids viable photosensitizers.
- Full Text:
- Date Issued: 2015
Study of the biotransformations and microbiological properties of cymbopogon citratus
- Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Authors: Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Date: 2015
- Subjects: Lemongras , Essences and essential oils
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19737 , vital:43197
- Description: Variations in the essential oil yield, chemical composition and kinetics of chemical transformation, antibacterial, and antioxidant properties of the Cymbopogon citratus cultivated in Alice, Eastern Cape of South Africa, over a period of 12 months using the solvent-free microwave extraction and the modified forms of conventional hydrodistillation methods have been evaluated. The modified forms involve variation in the pH medium to effect extraction and to obtain the whole leaf extracts of Cymbopogon citratus (lemongrass). The GC-MS analyses of the essential oils revealed the presence of 10, 11, 13, and 9 principal compounds in the microwave, extraction, hydrodistillation (water-distilled), hydrodistillation (aciddistilled and hydrodistillation (base-distilled), respectively with citral being the prominent compound in all the various extraction methods, with the water-distilled method having the highest cumulative citral content under the period specified. Each of the components of the oils varied in quantity and quality of yield at different points of the year. Different extraction methods produce different compounds. Increase in the amount of citral content was observed during the maturation stage of Cymbopogon citratus in all the extraction methods. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration (MIC) values were determined on the oils and extracts of Cymbopogon citratus using agar dilution method. The essential oils obtained using all the methods of extraction showed activity against all the tested bacteria at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the acid-distilled varied between 1.25 and 5.0 mg mL-1, while those obtained by both water- and base-distilled showed equal activity on the microorganisms with the MIC ranging between 2.5 and 10 mg mL-1. The microwave extraction showed the least activity with the MIC of 10 mg mL-1. This however suggested that the oils obtained through acid-distillation showed the greatest activity than all other methods of extraction. Activity of the various extracts on bacteria showed that the ethanol extract had the highest activity on the tested organisms with MIC ranging between 0.625 and 1.25 mg mL-1. This was closely followed by the acid-extract (1.25 and 5.0 mg mL-1), methanol extract (1.25 and 10 mg mL-1), acetone extract (2.5 and 5.0 mg mL-1), and base extract (5.0 mg mL-1). Both cold water and hot water extracts showed the least activity of MIC, >10 mg mL-1. The antioxidant and free-radical scavenging activity of the obtained oils and extracts were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay, [(2,2ˊ-azino bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS), nitric oxide and ferric reducing power assays. The oils and extracts showed DPPH radical scavenging ability, but not as high as the standard drugs. The base extract showed a higher reducing power than the standard drug, rutin. There were significant differences in the phytochemicals contents of the various leaf extracts. The acetone extract has the highest flavonol, proanthocyanidin, and alkaloid contents. The ethanol extract showed the highest amount of phenolic content with the acid extract, having the least. Thin layer chromatography (TLC) and column chromatography was employed to obtain different fractions of extracts using four eluent solvent systems of varying polarities: toluene, petroleum ether, hexane and ethyl acetate and sprayed with anisaldehyde. A single, visible spot of B-fraction was developed, collected and analyzed as 1-methyl-2,4,5- trinitroimidazole with renown valuable properties. , Thesis (PhD) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015
- Authors: Ajayi, Emmanuel Olusegun https://orcid.org/0000-0002-0838-4948
- Date: 2015
- Subjects: Lemongras , Essences and essential oils
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/19737 , vital:43197
- Description: Variations in the essential oil yield, chemical composition and kinetics of chemical transformation, antibacterial, and antioxidant properties of the Cymbopogon citratus cultivated in Alice, Eastern Cape of South Africa, over a period of 12 months using the solvent-free microwave extraction and the modified forms of conventional hydrodistillation methods have been evaluated. The modified forms involve variation in the pH medium to effect extraction and to obtain the whole leaf extracts of Cymbopogon citratus (lemongrass). The GC-MS analyses of the essential oils revealed the presence of 10, 11, 13, and 9 principal compounds in the microwave, extraction, hydrodistillation (water-distilled), hydrodistillation (aciddistilled and hydrodistillation (base-distilled), respectively with citral being the prominent compound in all the various extraction methods, with the water-distilled method having the highest cumulative citral content under the period specified. Each of the components of the oils varied in quantity and quality of yield at different points of the year. Different extraction methods produce different compounds. Increase in the amount of citral content was observed during the maturation stage of Cymbopogon citratus in all the extraction methods. Quantitative evaluation of antibacterial activity, minimum inhibitory concentration (MIC) values were determined on the oils and extracts of Cymbopogon citratus using agar dilution method. The essential oils obtained using all the methods of extraction showed activity against all the tested bacteria at a concentration of 10 mg mL-1. The minimum inhibitory concentrations for the acid-distilled varied between 1.25 and 5.0 mg mL-1, while those obtained by both water- and base-distilled showed equal activity on the microorganisms with the MIC ranging between 2.5 and 10 mg mL-1. The microwave extraction showed the least activity with the MIC of 10 mg mL-1. This however suggested that the oils obtained through acid-distillation showed the greatest activity than all other methods of extraction. Activity of the various extracts on bacteria showed that the ethanol extract had the highest activity on the tested organisms with MIC ranging between 0.625 and 1.25 mg mL-1. This was closely followed by the acid-extract (1.25 and 5.0 mg mL-1), methanol extract (1.25 and 10 mg mL-1), acetone extract (2.5 and 5.0 mg mL-1), and base extract (5.0 mg mL-1). Both cold water and hot water extracts showed the least activity of MIC, >10 mg mL-1. The antioxidant and free-radical scavenging activity of the obtained oils and extracts were tested by means of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH+) assay, [(2,2ˊ-azino bis-(3-ethylbenzothiazoline-6-sulfonic acid)] (ABTS), nitric oxide and ferric reducing power assays. The oils and extracts showed DPPH radical scavenging ability, but not as high as the standard drugs. The base extract showed a higher reducing power than the standard drug, rutin. There were significant differences in the phytochemicals contents of the various leaf extracts. The acetone extract has the highest flavonol, proanthocyanidin, and alkaloid contents. The ethanol extract showed the highest amount of phenolic content with the acid extract, having the least. Thin layer chromatography (TLC) and column chromatography was employed to obtain different fractions of extracts using four eluent solvent systems of varying polarities: toluene, petroleum ether, hexane and ethyl acetate and sprayed with anisaldehyde. A single, visible spot of B-fraction was developed, collected and analyzed as 1-methyl-2,4,5- trinitroimidazole with renown valuable properties. , Thesis (PhD) -- Faculty of Science and Agriculture, 2015
- Full Text:
- Date Issued: 2015
A critical assessment of economic policies and their impact on entrepreneurship development in South Africa: a case of Khayelitsha Township in Cape Town
- Oduwole, Olusola https://orcid.org/0000-0002-1563-7392
- Authors: Oduwole, Olusola https://orcid.org/0000-0002-1563-7392
- Date: 2015
- Subjects: Entrepreneurship , Economic policy , Economic development -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/26302 , vital:65236
- Description: The complexity of the South African society due to past systematic exclusion of some communities from economic activities resulted in the triple challenge of poverty, inequality and unemployment. Although various economic policies had been developed since the advent of the democratic dispensation in 1994, these policies focused on levelling the economic environment, poverty alleviation and massive social security system. However, despite all the interventions, South Africa remains one of the most unequal societies in the world. This is profiled by the mushrooming of informal settlements around cities with job seekers and frequent protests by people who are impatient to experience improvement in their quality of life and who feel cheated out of their social contract. Advocacy from the governing party’s tripartite alliance towards a developmental state had placed more obligations on the government. This requires deliberate interventions through policies implementation to improve or at best alleviate the well-being of the citizenry. A survey conducted in the township of Khayelitsha to assess the impact of such economic policies on the development of entrepreneurship. Khayelitsha is one of South Africa’s largest townships, an informal settlement profiled by unemployment, poor infrastructure and unavailability of basic services. The study explored the entrepreneurial perception, start-up barriers, entrepreneurship climate, and general cultural factors relating to the environment of entrepreneurship development. The results reveal that despite the various economic policies, high level of unwillingness of citizens towards entrepreneurial activity and business venture is rife notwithstanding the high level of unemployment and poverty. The antidote to these challenges would be a rapid entrepreneurship drive among people most affected that would cause them to mind their own business” and become “masters of their own destinies. Given the complexity and massiveness of the challenges, the conclusion shows that a pragmatic solution is required. Therefore, the emancipation of entrepreneurship development in South Africa townships needs attention. The recommended solution is a pragmatic and innovative strategy based on the acronyms NEEDS HELP which stand for Neighbourhood Enhancement and Environmental Development Strategy and Holistic Entrepreneurial Lifestyle Programme. , Thesis (PhD) -- Faculty of Management and Commerce, 2015
- Full Text:
- Date Issued: 2015
- Authors: Oduwole, Olusola https://orcid.org/0000-0002-1563-7392
- Date: 2015
- Subjects: Entrepreneurship , Economic policy , Economic development -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/26302 , vital:65236
- Description: The complexity of the South African society due to past systematic exclusion of some communities from economic activities resulted in the triple challenge of poverty, inequality and unemployment. Although various economic policies had been developed since the advent of the democratic dispensation in 1994, these policies focused on levelling the economic environment, poverty alleviation and massive social security system. However, despite all the interventions, South Africa remains one of the most unequal societies in the world. This is profiled by the mushrooming of informal settlements around cities with job seekers and frequent protests by people who are impatient to experience improvement in their quality of life and who feel cheated out of their social contract. Advocacy from the governing party’s tripartite alliance towards a developmental state had placed more obligations on the government. This requires deliberate interventions through policies implementation to improve or at best alleviate the well-being of the citizenry. A survey conducted in the township of Khayelitsha to assess the impact of such economic policies on the development of entrepreneurship. Khayelitsha is one of South Africa’s largest townships, an informal settlement profiled by unemployment, poor infrastructure and unavailability of basic services. The study explored the entrepreneurial perception, start-up barriers, entrepreneurship climate, and general cultural factors relating to the environment of entrepreneurship development. The results reveal that despite the various economic policies, high level of unwillingness of citizens towards entrepreneurial activity and business venture is rife notwithstanding the high level of unemployment and poverty. The antidote to these challenges would be a rapid entrepreneurship drive among people most affected that would cause them to mind their own business” and become “masters of their own destinies. Given the complexity and massiveness of the challenges, the conclusion shows that a pragmatic solution is required. Therefore, the emancipation of entrepreneurship development in South Africa townships needs attention. The recommended solution is a pragmatic and innovative strategy based on the acronyms NEEDS HELP which stand for Neighbourhood Enhancement and Environmental Development Strategy and Holistic Entrepreneurial Lifestyle Programme. , Thesis (PhD) -- Faculty of Management and Commerce, 2015
- Full Text:
- Date Issued: 2015
If I Stay Right Here
- Authors: Ngamlana, Chwayita
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193498 , vital:45337
- Description: My novella concerns the dynamics of a relationship between two girls. It shows the heterosexual‐like nature of the relationship rather than dwelling on the pressures on lesbians from society as a whole. At its core is the raw emotion and passion of the relationship, which is at the same time toxic, destructive and volatile because of their class differences and other insecurities. The work is influenced by the grit, openness, and innovation of several contemporary writers. , Thesis (MA) -- Faculty of Humanities, Institute for the Study of English in Africa, 2015
- Full Text:
- Date Issued: 2015
- Authors: Ngamlana, Chwayita
- Date: 2015
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193498 , vital:45337
- Description: My novella concerns the dynamics of a relationship between two girls. It shows the heterosexual‐like nature of the relationship rather than dwelling on the pressures on lesbians from society as a whole. At its core is the raw emotion and passion of the relationship, which is at the same time toxic, destructive and volatile because of their class differences and other insecurities. The work is influenced by the grit, openness, and innovation of several contemporary writers. , Thesis (MA) -- Faculty of Humanities, Institute for the Study of English in Africa, 2015
- Full Text:
- Date Issued: 2015
The effects of gold coated and uncoated zinc oxide nanohexagons on the photophysicochemical properties of the low symmetry zinc phthalocyanine
- D'Souza, Sarah, Ogbodu, Rachael, Nyokong, Tebello
- Authors: D'Souza, Sarah , Ogbodu, Rachael , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189077 , vital:44814 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.06.088"
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results.
- Full Text:
- Date Issued: 2015
- Authors: D'Souza, Sarah , Ogbodu, Rachael , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189077 , vital:44814 , xlink:href="https://doi.org/10.1016/j.molstruc.2015.06.088"
- Description: A new low symmetry, Zn phthalocyanine monosubstituted with diethylaminoethanethiol (mDEAET ZnPc) was synthesized and characterized. This work reports on its photophysical and photochemical properties of mDEAET ZnPc alone and when conjugated to gold coated and uncoated zinc oxide nanohexagons (ZnO NHXs). The photophysicochemical properties generally improved in the presence of the ZnO NHXs. These complexes were also tested for their photodynamic antimicrobial activity against Staphylococcus aureus (S. aureus). The Pc alone showed remarkable growth inhibition even at concentrations as low as 0.05 mg/mL. The conjugates showed a high photoinactivation of S. aureus after 30 min at a fluence of 90 mW cm−2 at a concentration of 0.05 mg/mL. The ZnPc-ZnO NHX conjugates produced the best antimicrobial results.
- Full Text:
- Date Issued: 2015
The politics of philosophy in Africa
- Jones, Ward E, Metz, Thaddeus
- Authors: Jones, Ward E , Metz, Thaddeus
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275733 , vital:55074 , xlink:href="https://doi.org/10.1080/02580136.2015.1104797"
- Description: The background to the present discussion is the prevalence of political and personal criticisms in philosophical discussions about Africa. As philosophers in South Africa—both white and black—continue to philosophise seriously about Africa, responses to their work sometimes take the form of political and personal criticisms of, if not attacks on, the philosopher exploring and defending considerations about the African continent. One of us (TM) has been the target of such critiques in light of his work. Our aim in this conversation is not to diminish or deflect such critiques. On the contrary, our aim is to understand them, to make them as strong as possible, and to bring them into the cooler realm of philosophical discussion.
- Full Text:
- Date Issued: 2015
- Authors: Jones, Ward E , Metz, Thaddeus
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275733 , vital:55074 , xlink:href="https://doi.org/10.1080/02580136.2015.1104797"
- Description: The background to the present discussion is the prevalence of political and personal criticisms in philosophical discussions about Africa. As philosophers in South Africa—both white and black—continue to philosophise seriously about Africa, responses to their work sometimes take the form of political and personal criticisms of, if not attacks on, the philosopher exploring and defending considerations about the African continent. One of us (TM) has been the target of such critiques in light of his work. Our aim in this conversation is not to diminish or deflect such critiques. On the contrary, our aim is to understand them, to make them as strong as possible, and to bring them into the cooler realm of philosophical discussion.
- Full Text:
- Date Issued: 2015