Sustainability assessment using a unit-based sustainability assessment tool: The case of three teaching departments at Rhodes University, South Africa
- Authors: Togo, Muchaiteyi
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386863 , vital:68182 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122776"
- Description: A sustainability assessment study was performed with three teaching departments at Rhodes University – Ichthyology and Fisheries Science, Anthropology, and Accounting. The assessment used a Unit-based Sustainability Assessment Tool (USAT) and was guided by systems thinking and the ontological framework provided by critical realism. Results of the study showed that the Department of Ichthyology and Fisheries Science had a higher integration of sustainability issues in its activities than the other departments sampled, with Accounting having the lowest integration. Interviews conducted with departmental heads and content analyses of documents revealed differences in sustainability issues addressed and in approaches used in tackling them among these departments. The study is intended to inform the Mainstreaming of Environment and Sustainability in African (MESA) Universities Partnership, which promotes mainstreaming environment and sustainability in universities during the United Nations Decade of Education for Sustainable Development. The study does not provide answers to mainstreaming activities, but opens up space to debate and deliberate how to deal with the mainstreaming of sustainability in universities. It identified some of the challenges to be addressed in university-wide mainstreaming work, and affirmed the need for systems thinking in bringing about change at institutional level to extend changes taking place in individual teaching contexts.
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- Date Issued: 2008
Employee performance, leadership style and emotional intelligence
- Authors: Hayward, Brett A , Amos, Trevor L , Baxter, Jeremy
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270077 , vital:54393 , xlink:href="https://hdl.handle.net/10520/EJC17031"
- Description: Purpose: The purpose of this research is to explore the relationship between employee performance, leadership style and emotional intelligence in the context of a South African parastatal. Problem Investigated: There is a lack of literature and empirical research on the type of leadership required to achieve high levels of employee performance within South African parastatals. Methodology: The Multifactor Leadership Questionnaire (MLQ) was used to determine leadership style, while the Emotional Competency Profiler (ECP) was used to determine the emotional intelligence of the sample of leaders. Employee performance data was provided by the parastatal, based on their performance management system. Data was analysed using correlation analysis, multiple regression analysis, the standard regression ANOVA/F-test, t-tests and Cronbach alpha reliability coefficient. Findings: The findings of the research show that the ECP is a reliable measure of emotional intelligence and that while the MLQ is a reliable measure of transformational leadership, it is not a reliable measure of transactional leadership. The results of the correlation analysis show a positive significant relationship between emotional intelligence and transformational leadership and a negative significant relationship between employee performance and emotional intelligence. The results of regressing employee performance on emotional intelligence and transformational leadership show that emotional intelligence and transformational leadership have no significant effect on employee performance. The results of the regression models of the research could be biased by the lack of variance in employee performance data. Value of the Research: The value of the research lies in it confirming the MLQ as a reliable measure of transformational leadership and the ECP as a reliable measure of emotional intelligence. The finding of a positive significant relationship between emotional intelligence and transformational leadership is a valuable contribution to the literature. Conclusion: Although a positive significant relationship between emotional intelligence and transformational leadership was found, there is a need for further research to determine the type of leadership best suited to achieve high levels of employee performance within the parastatal.
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- Date Issued: 2008
Electrocatalytic and photosensitizing behavior of metallophthalocyanine complexes
- Authors: Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/265908 , vital:53899 , xlink:href="https://doi.org/10.1142/S1088424608000388"
- Description: Electrocatalytic or photosensitizing (photocatalytic) properties of metallophthalocyanine (MPc) complexes are dependent on the central metal. Electrocatalytic behavior is observed for electroactive central metals such as Co, Mn and Fe, whereas photosensitizing behavior is observed for diamagnetic metals such as Al, Zn and Si. In the presence of nanoparticles such as quantum dots, the photosensitizing behavior of MPc complexes is improved. Carbon nanotubes enhance the electrocatalytic behavior of MPc complexes.
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- Date Issued: 2008
Synthesis and electrochemical characterisation of a near infrared absorbing oxo vanadium (IV) octapentylthio-phthalocyanine
- Authors: Mbambisa, Gcineka , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/266008 , vital:53909 , xlink:href="https://doi.org/10.1016/j.poly.2008.06.004"
- Description: The synthesis of an α-substituted phthalocyanine oxo vanadium(IV) 1,4,8,11,15,18,22,25-octapentathiophthalocyanine (4) which absorbs at 850 nm in dichloromethane is reported. The complex is purple in colour and becomes green on reduction. The cyclic and square wave voltammetries of the complex show five redox couples. The spectroelectrochemical data showed only ring based processes. The ring reduced species is observed at wavelengths greater than 680 nm rather than the usual 500–600 nm range typical of ring reduced phthalocyanine complexes.
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- Date Issued: 2008
Interaction of water-soluble thiol capped CdTe quantum dots and bovine serum albumin
- Authors: Idowu, Mopelola , Lamprecht, Emmanuel , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/265974 , vital:53906 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.02.008"
- Description: Luminescent water-soluble CdTe quantum dots (QDs) capped with different thiol carboxylic acids were synthesized in aqueous medium and then cross linked to bovine serum albumin (BSA) with 1-ethyl3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). Enhancement of fluorescence emission intensity occurred for QDs in the presence of bovine serum albumin (BSA, mixed or linked) signifying inhibition of non-radiative recombination of the surface vacancies. Fluorescence studies reveal a positive deviation behaviour suggesting the occurrence of static and dynamic mechanisms of quenching together which was accounted for by the modified Stern–Volmer equation.
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- Date Issued: 2008
Energy transfer in zinc porphyrin–phthalocyanine heterotrimer and heterononamer studied by fluorescence resonance energy transfer (FRET)
- Authors: Durmus, Mahmut , Chen, Jiyao Y , Zhao, Zhixin X , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268599 , vital:54213 , xlink:href="https://doi.org/10.1016/j.saa.2007.07.010"
- Description: Two or eight zinc triphenyl porphyrins were conjugated with Zn-phthalocyanine or H2-phthalocyanine to form ZnPc–(ZnTPP)2, ZnPc–(ZnTPP)8, H2Pc–(ZnTPP)2 and H2Pc–(ZnTPP)8. Energy transfers from the porphyrin moiety to phthalocyanine part were quantitatively studied with the modality of fluorescence resonance energy transfer (FRET). By measuring the fluorescence increment from the phthalocyanine moiety and the decrease from porphyrin part under selective excitation at the B band of the porphyrin part in those conjugated compounds and their equimolar mixture of compositions, energy transfer efficiencies were estimated to be 90% for H2Pc–(ZnTPP)8 and ZnPc–(ZnTPP)8, and 60%, 30% for ZnPc–(ZnTPP)2 and H2Pc–(ZnTPP)2, respectively.
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- Date Issued: 2008
Pragmatic research design
- Authors: Amos, Trevor L , Pearse, Noel J
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270943 , vital:54494 , xlink:href="https://academic-publishing.org/index.php/ejbrm/article/view/1230/1193"
- Description: The creation of wealth is an important issue in any society, and entrepreneurship is regarded as an important catalyst in the creation of new wealth. This presents a challenge to develop entrepreneurship successfully. An important site for the development of entrepreneurship is higher education. The challenge however, is that there is a lack of a general understanding on how to educate students for entrepreneurship. In addition, current thought and practice on entrepreneurship education is historically biased, implying that graduates are essentially prepared for the past instead of for the future. From the perspective of higher education, the problem is how to develop current students to be entrepreneurial in the future. What is needed is to project into the future and then to develop an understanding of what should be taught as well as how it should be taught today. A versatile research technique that can assist in achieving this objective is the Delphi technique, as it is used to conduct futures research or research into areas where knowledge is incomplete. The Delphi method is a type of group interview, using the collective opinion of knowledgeable experts. The technique makes use of several rounds of data collection and feedback to create a consensus of opinion. Making use of the Delphi technique, research is being designed that will formulate expert‑based strategic guidelines on entrepreneurial education within the South African higher education sector. The aim of this paper is to illustrate the research design considerations that arise in the use of the Delphi technique for this purpose and how they are addressed. The main characteristics of the Delphi are presented and arguments for the use of the Delphi within a constructivist paradigm are discussed. Practical issues related to the design of the Delphi, panel‑member selection, and the formulation of panel questions, are examined. In illustrating these design considerations, the paper demonstrates a pragmatic approach to research design as well as the importance of creating coherence between the research question, the research paradigm, the research method and its use, encouraging research practitioners to adopt a more systematic, deliberate and philosophically‑based approach to research design.
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- Date Issued: 2008
Tuning the redox properties of Co-N4 macrocyclic complexes for the catalytic electrooxidation of glucose
- Authors: Villagra, Evelyn , Bedioui, Fethi , Nyokong, Tebello , Canales, J Carlos , Sancy, Mamie , Páez, Maritza A , Costamagna, Juan , Zagal, Jose H
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268675 , vital:54221 , xlink:href="https://doi.org/10.1016/j.electacta.2008.02.006"
- Description: Graphite electrodes modified with four different cobalt N4 macrocyclics, namely Co tetrapentapyridinophthalocyanine, (CoTPenPyrPc), Co tetrapyridinoporphyrazine (CoTPyPz), Co octa(hydroxyethylthio)phthalocyanine (CoOEHTPc) and Co tetranitrophthalocyanine (CoTNPc) exhibit catalytic activity for the oxidation of glucose in alkaline media. The purpose of this work is to establish correlations between the catalytic activity of these complexes and their redox potential. The activity of the different modified electrodes was tested by linear voltammetry under hydrodynamic conditions using the rotating disk technique. Tafel plots constructed from mass-transport corrected currents give slopes ranging from 0.080 to 0.160 V/decade for the different catalysts which suggests that a first one-electron step is rate controlling with the symmetry of the energy barrier depending on the nature of the ligand of the Co complex. A plot of log I versus the Co(II)/(I) formal potential gives a volcano curve that also includes catalysts studied previously. This illustrates the concept that the formal potential of the catalyst needs to be tuned to a certain value for achieving maximum activity. A theoretical interpretation of these results is given in terms of Langmuir isotherms for the adsorption of glucose on the Co sites of the surface-confined metal complexes.
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- Date Issued: 2008
A Bernsteinian analysis of the integration of natural resource management in the curriculum of a rural disadvantaged school
- Authors: Nsubuga, Yvonne
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386415 , vital:68139 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122771"
- Description: Knowledge integration is one of the key principles that underpin curriculum reform in post-apartheid South Africa. One form of teacher support that has been adopted in South Africa is to provide schools throughout the country with samples of pedagogic texts such as curriculum documents and examination exemplars to act as guidelines to teachers as they implement this new curriculum requirement. In the isolated and under-resourced rural schools of South Africa, these texts are the main form of curriculum guidance to teachers. Hence the knowledge integration principles and messages conveyed within these texts are of crucial importance. One contributory factor to the lack of information on knowledge integration at rural underresourced schools is the lack of simple and effective research tools by which to analyse and compare the extent of knowledge integration within pedagogic texts and classroom practices. This article reports on a Bernstein informed analysis that was carried out on three different Grade 10 Life Sciences pedagogic texts in order to assess the extent to which they integrate natural resource management (NRM). The study involved the construction of two indicator frameworks as the research tools with which the analysis was conducted. Results from the analysis showed that although the official Grade 10 Life Sciences pedagogic texts contained very high levels of NRM integration, this was not the case for the Grade 10 Life Sciences text that was produced at the school level. The study provides useful insight into curriculum recontextualisation at a rural under-resourced school through the lens of NRM integration within the Grade 10 Life Sciences pedagogic texts. Such insight has the potential to contribute to better curriculum design and implementation strategies to service schools. This will hopefully help to narrow the gap that currently exists between the official and enacted curricula.
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- Date Issued: 2008
Photocatalytic oxidation of 1-hexene using GaPc and InPc octasubstituted derivatives
- Authors: Chauke, Vongani , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268611 , vital:54214 , xlink:href="https://doi.org/10.1016/j.molcata.2008.04.003"
- Description: Photocatalytic oxidation of 1-hexene by GaPc (1a–1c) and InPc (2a–2c) derivatives (Pc = phthalocyanine) is hereby presented. The derivatives studied are Pc octasubstituted with phenoxy (a), 4-tert-butylphenoxy (b) or benzyloxyphenoxy (c) at the peripheral positions. The photocatalytic oxidation products for 1-hexene were 1,2-epoxyhexane and 1-hexen-3-ol. The %conversion values of 1-hexene and %selectivity of 1,2-epoxyhexane were generally higher for InPc derivatives. Even though InPc derivatives showed better photocatalytic results than GaPc derivatives, the former were less stable relative to the latter. Both type I and type II mechanism were implicated in the photocatalysis mechanism.
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- Date Issued: 2008
Synthesis, photophysical and photochemical studies on long chain zinc phthalocyanine derivatives
- Authors: Ogunsipe, Abimbola , Durmus, Mahmut , Atilla, Devrim , Gürek, Ayşe Gül , Ahsen, Vefa , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/266019 , vital:53910 , xlink:href="https://doi.org/10.1016/j.synthmet.2008.06.007"
- Description: The synthesis and characterization of 2,9,16,23-chloro-3,10,17,24-triethyleneoxysulphanylphthalocyaninato zinc(II) (CTESZnPc) is described. The photophysics and photochemistry of CTESZnPc and those of tetrakis(triethyleneoxysulphanyl)zinc phthalocyanine (TTESZnPc) and octakis(triethyleneoxysulphanyl)zinc phthalocyanine (OTESZnPc), are presented and compared with those of unsubstituted zinc phthalocyanine (ZnPc). The presence of triethyleneoxysulphanyl substituents on the ZnPc ring gave rise to higher values of singlet oxygen (ΦΔ) and photodegradation (ΦPd) quantum yields in DMF. However, TTESZnPc, OTESZnPc and CTESZnPc are less fluorescent than ZnPc, judging from their fluorescence quantum yield (ΦF) values. Fluorescence was lower in toluene than in DMF due to aggregation in the former solvent. Triplet quantum yield (ΦT) values were found to increase with the presence of substituents on the ZnPc ring, while triplet lifetimes (τT) were found to vary linearly with the logarithms of solvent viscosities. The fluorescences of the substituted ZnPc complexes were effectively quenched by benzoquinone (BQ), and the quenching data analyzed by the Stern–Volmer equation. The Stern–Volmer constants and the diffusion-controlled bimolecular rate constants were calculated.
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- Date Issued: 2008
in the council chambers
- Authors: Krueger, Anton
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/229862 , vital:49718 , xlink:href="https://hdl.handle.net/10520/EJC47802"
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- Date Issued: 2008
Photoinduced energy transfer between water-soluble CdTe quantum dots and aluminium tetrasulfonated phthalocyanine
- Authors: Idowu, Mopelola , Chen, Ji-Yao , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268564 , vital:54210 , xlink:href="https://doi.org/10.1039/B707808K"
- Description: Thiol stabilized CdTe quantum dots (QDs) synthesized in aqueous phase were used as energy donors to aluminium tetrasulfonated phthalocyanine (AlTSPc) through fluorescence resonance energy transfer (FRET). Energy transfer occurred from the QDs to AlTSPc upon photoexcitation of the QDs. An enhancement in efficiency of energy transfer with the nature of the carboxylic thiol stabilizers on the QDs was observed. The results showed that for enhanced FRET to occur, the donor–acceptor distance has to be lower than the critical distance. The quenching constant K as well as the binding constant kb values were calculated suggesting strong interaction of the QDs with the AlTSPc. Study of the photophysics of AlTSPc in the presence of the QDs revealed a high triplet state yield, hence the possibility of using QDs in combination with phthalocyanines as photosensitizers in photodynamic therapy. The triplet state lifetimes of AlTSPc in the presence of the QDs were calculated and the lifetime in the presence of CdTe capped with 3-mercaptopropionic acid (MPA) was found to be the longest. MPA capped QD in a mixture with AlTSPc resulted in long triplet lifetime and high triplet yield of the latter, and high energy transfer efficiency, hence was found to be most suitable as a potential candidate for photodynamic therapy of cancer studies.
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- Date Issued: 2008
Adsorption of 4-nitrophenol onto Amberlite® IRA-900 modified with metallophthalocyanines
- Authors: Marais, Eloïse , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268576 , vital:54211 , xlink:href="https://doi.org/10.1016/j.jhazmat.2007.06.096"
- Description: The adsorption of 4-nitrophenol using commercially available Amberlite® IRA-900 modified with metal phthalocyanines (MPc) was investigated. The metallophthalocyanines immobilised onto the surface of Amberlite® IRA-900 include Fe (FePcS4), Co (CoPcS4) and Ni (NiPcS4) tetrasulphophthalocyanines, and differently sulphonated phthalocyanine mixtures of Fe (FePcSmix), Co (CoPcSmix) and Ni (NiPcSmix). Adsorption rates were fastest for the modified adsorbents at a loading of 1 × 10−3 g MPc/g Amberlite, at pH 9. The highest amount of 4-NP removal was obtained on FePcSmix modified Amberlite® IRA-900 with Qt = 42.9 mmol g−1 and adsorption efficiency of 86%. The recovery efficiency of 4-NP within 150 min was 76%. Using the Langmuir–Hinshelwood kinetic model, the complexes showed an order of 4-nitrophenol adsorption to be as follows: CoPcSmix > NiPcS4 > NiPcSmix > FePcS4 > FePcSmix > CoPcS4. The MPc modified Amberlite® IRA-900 was used repeatedly, following removal of 4-NP by nitric acid, without any significant loss of activity.
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- Date Issued: 2008
Synthesis and photophysical properties of lead phthalocyanines
- Authors: Modibane, D.K. , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268636 , vital:54216 , xlink:href="https://doi.org/10.1016/j.poly.2007.12.004"
- Description: This work reports on the synthesis and photophysical parameters of tetra-and octa-substituted new lead phthalocyanines. The complexes synthesized are: 1,4-(tetraphenoxyphthalocyaninato)lead (7a), 1,4-(tetra-tert-butylphenoxyphthalocyaninato)lead (7b), 2,3-(tetraphenoxyphthalocyaninato)lead (8a), 2,3-(tetra-tert-butylphenoxyphthalocyaninato)lead (8b), 2,3-octaphenoxyphthalocyaninatolead (9a) 2,3-[octakis(4-t-butylphenoxyphthalocyaninato)]lead (9b). Photophysical properties were studied for these complexes in a dimethylsulfoxide, dimethylformamide, toluene, tetrahydrofuran and chloroform. The fluorescence spectra were different from excitation spectra due to demetallation upon excitation. High triplet quantum yields ranging from 0.70 to 0.88 (in DMSO, DMF and toluene) and low triplet lifetimes (20–50 μs in DMSO, and more than 10 μs in the rest of the solvents) were observed due to the presence of heavy atom.
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- Date Issued: 2008
Electrochemical and electrocatalytic properties of α-substituted manganese and titanium phthalocyanines
- Authors: Nombona, Nolwazi , Tau, Prudence , Sehlotho, Nthapo , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268587 , vital:54212 , xlink:href="https://doi.org/10.1016/j.electacta.2007.11.046"
- Description: This work reports on the synthesis of manganese and titanium phthalocyanine complexes that are tetra-substituted at four non-peripheral positions with amino ligands. The complexes are investigated for the first time for their electrochemical properties using cyclic voltammetry, rotating disc electrode voltammetry and spectroelectrochemistry. Electropolymerisation on a glassy carbon electrode was performed with ease and the modified electrodes were investigated for electrocatalysis of nitrite oxidation. Nitrite oxidation to nitrate is confirmed from the transfer of a total of two electrons.
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- Date Issued: 2008
What future subordinates will value in their leaders
- Authors: Cox, A , Amos, Trevor L , Baxter, Jeremy
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/270992 , vital:54499 , xlink:href="https://hdl.handle.net/10520/EJC51031"
- Description: Leaders should not randomly choose a leadership style. To be effective, leaders need to ensure that their leadership style is congruent with what subordinates value. The focus of this study is on what the future South African graduate workforce will value in a leader. The female and male respondents in this study emphasise similar leadership values, indicating that there is no distinct set of competencies that will be valued separately by males and females. The same was found for respondents of different cultures, namely African, Coloured, Indian, White and other. With respect to both gender and culture, the respondents emphasise a mixture of African and Western leadership values. This supports the idea that to be effective in South Africa, leaders need to understand the prevailing national cultural values before simply applying ''foreign'' leadership models and theories based upon cultural values found in the West. This research finds that irrespective of gender and culture in the South African workplace, to be effective, leaders need to be loyal and inspirational, have vision and integrity and must be open and honest with their subordinates. Leaders should avoid being autocratic, strict, religious, ritualistic and traditional. They should also avoid using consensus and perceived external control.
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- Date Issued: 2008
Electrocatalytic detection of amitrole on the multi-walled carbon nanotube–iron (II) tetra-aminophthalocyanine platform
- Authors: Siswana, Msimelelo P , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/265924 , vital:53901 , xlink:href="https://doi.org/10.3390/s8085096"
- Description: It is shown that iron(II) tetra-aminophthalocyanine complex electropolymerized onto a multi-walled carbon nanotube-modified basal plane pyrolytic graphite electrode greatly enhanced the electrocatalytic detetion of amitrole (a toxic herbicide), resulting in a very low detection limit (0.5 nM) and excellent sensitivity of 8.80±0.44 μA/nM, compared to any known work reported so far. The electrocatalytic detection of amitrole at this electrode occurred at less positive potential (~0.3 V vs Ag|ACl) and also revealed a typical coupled chemical reaction. The mechanism for this response is proposed. The electrode gave satisfactory selectivity to amitrole in the presence of other potential interfering pesticides in aqueous solutions.
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- Date Issued: 2008
The Postcolonial heart of African philosophy
- Authors: Tabensky, Pedro
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/305762 , vital:58610 , xlink:href="https://hdl.handle.net/10520/EJC96056"
- Description: This piece is one of among a handful that seek in the first instance to reveal the origin of African philosophy as an academic discipline, the source of its unity and distinctiveness. The discipline of African philosophy originates in tragedy, out of pain, confusion and rage stemming from colonial destruction; destruction that is responsible for what Fanon calls the ‘negro neurosis’ caused by what Biko would describe as the unbearable fusion of colonised and coloniser. I argue that the birth of African philosophy as an academic discipline is largely responsible for its character and, crucially, for its distinctive creative possibilities.
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- Date Issued: 2008
Photophysical and photochemical properties of tetrasulfonated silicon and germanium phthalocyanine in aqueous and non-aqueous media
- Authors: Idowu, Mopolela , Nyokong, Tebello
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/268624 , vital:54215 , xlink:href="https://doi.org/10.1016/j.jphotochem.2008.01.004"
- Description: The photophysical and photochemical properties of tetrasulfonated silicon and germanium phthalocyanine (SiPcS4 and GePcS4) in aqueous solution (phosphate-buffered saline (PBS) solution, pH 7.4) (in the presence and absence of cremophore EL (CEL)) and in dimethylsulphoxide (DMSO) were studied. The complexes have intense absorption in the visible/near-IR region though they highly aggregate in aqueous solution with a dimerization constant of ∼2 × 104 dm3 mol−1. The fluorescence excitation spectra however have only one band suggesting that only the monomer fluoresces. Both the quantum yields of the triplet state (ΦT) and the triplet lifetimes (τT) were found to be higher in DMSO compared to in aqueous solution. Aggregation is hindered by addition of cremophore EL in aqueous solution and this induced disaggregation caused an increased ΦT and τT probably due to the reduced interaction of the phthalocyanines with the aqueous medium in the presence of CEL.
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- Date Issued: 2008