Photophysical properties of newly synthesized fluorinated zinc phthalocyanines in the presence of CdTe quantum dots and the accompanying energy transfer processes
- Authors: Erdoğmuş, Ali , Moeno, Sharon , Litwinski, Christian , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/262671 , vital:53543 , xlink:href="https://doi.org/10.1016/j.jphotochem.2009.12.014"
- Description: The photophysical properties of two newly synthesized phthalocyanines (Pcs) were studied in the presence and the absence of 3-mercaptopropionic acid (MPA) capped quantum dots (QDs). Energy transfer processes resulting from the combination of QDs and the Pcs: 4-(tetrakis-5-(trifluoromethyl)-2-mercaptopyridinephthalocyaninato)zinc(II) (TtfmMPyZnPc, 3) and 4-(tetrakis-5-(trifluoromethyl)-2-pyridyloxyphthalocyaninato) zinc(II) (TtfmPyZnPc, 4) were also studied. The photophysical properties of the Pcs in the presence of QDs were enhanced and Förster resonance energy transfer (FRET) was observed with the phthalocyanines used. The efficiency of FRET between the QDs and TtfmMPyZnPc and TtfmPyZnPc was found to be 0.31% and 0.45% in DMSO and 0.24% and 0.32% in pyridine, respectively. The triplet state quantum yields for TtfmMPyZnPc and TtfmPyZnPc were found to be 0.86 and 0.74 in DMSO and 0.83 and 0.76 in pyridine.
- Full Text:
- Date Issued: 2010
A research tool for analysing and monitoring the Extent to which Environmental issues are integrated into teachers’ lessons
- Authors: Nsubuga, Yvonne
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386447 , vital:68142 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122246"
- Description: South Africa enjoys strong policy support for the integration of environmental issues into school curricula. However, much doubt exists over the extent to which this has been converted into appropriate classroom practice at the majority of under-resourced rural schools in the country. This article reports on a study which piloted a research tool which can be used to analyse teachers’ lessons, with the aim of gaining insight into the extent to which they integrate natural resource management issues. The research tool was based on Bernstein’s concept of classification and consisted of five indicators of natural resource management integration into Life Sciences lessons. The study contributes to the design of research tools that can be used to analyse and monitor the integration of environmental issues into teachers’ lessons. It also provides some insight into the environmental content of a sample of Grade 10 Life Sciences lessons at four rural underresourced schools in the Eastern Cape.
- Full Text:
- Date Issued: 2011
The photophysical studies of Pluronic F127/P123 micelle mixture system loaded with metal free and Zn 5, 10, 15, 20-tetrakis [4-(benzyloxy) phenyl] porphyrins
- Authors: Managa, Muthumuni , Ngoy, Bokolombe P , Nyokong, Tebello
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/188932 , vital:44799 , xlink:href="https://doi.org/10.1016/j.jphotochem.2017.02.018"
- Description: Binary mixtures of Pluronics are studied as drug nanocarriers in this work. H2 and Zn 5,10,15,20-tetrakis[4-(benzyloxy) phenyl] porphyrin were encapsulated onto binary micelle mixture of Pluronic F127/P123. The fluorescence and singlet oxygen generating behaviour of the porphyrins were investigated following incorporation. The fluorescence quantum yield for H2TBnOPP (ΦF = 0.034) was higher than that of ZnTBnOPP (ΦF = 0.023) and decreased when ZnTBnOPP or H2TBnOPP when in the presence of Pluronic F127/P123 binary mixtures. The kq values were 2.8 × 108 and 3.7 × 108 M−1 s−1, for H2TBnOPP + Pluronic F127/P123 and ZnTBnOPP + Pluronic F127/P123 in water, respectively. The binding constants (Kb) were 1.58 × 105 M−1 and 1.02 × 105 M−1 for ZnTBnOPP + Pluronic F127/P123 and H2TBnOPP + Pluronic F127/P123, respectively.
- Full Text:
- Date Issued: 2017
Applications of polymerized metal tetra-amino phthalocyanines towards hydrogen peroxide detection
- Authors: Mashazi, Philani N , Togo, Chumunorwa , Limson, Janice , Nyokong, Tebello
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/261840 , vital:53451 , xlink:href="https://doi.org/10.1142/S1088424610001994"
- Description: This work reports the use of metallo tetra-amino phthalocyanines (MTAPc, M = Co and Mn) polymer thin films on gold and glassy carbon electrode surfaces for the detection and monitoring of hydrogen peroxide (H2O2). The polymer-modified electrodes were characterized using electrochemical and microscopic-based methods. Atomic force microscopy (AFM) was used to study the bare and polymer-modified ITO surfaces. The electrocatalytic reduction of H2O2 with glassy carbon polymer-modified electrodes gave higher current densities compared to their gold counterparts. The electroanalytical properties of H2O2 were obtained using a real-time calibration curve of the amperometric determination in pH 7.4 aqueous solution. The limits of detection (LoD) of the polymer-modified electrodes towards electroreduction of H2O2 were of the order of 10–7 M, with high sensitivity ranging from 6.0–15.4 mA.mM-1.cm-2.
- Full Text:
- Date Issued: 2010
Book Review: From the Outside In
- Authors: Magadla, Siphokazi
- Date: 2019
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/298628 , vital:57722 , xlink:href="https://doi.org/10.1080/10220461.2019.1610042"
- Description: From the Outside In: Domestic Actors and South Africa’s Foreign Policy presents an exciting collection of chapters that explore various and often-ignored domestic actors and their relationships within the state, including government departments and local government; and non-governmental organisations such as labour unions, big business and social movements. The editors evoke the imagery of the ‘chess game of foreign policy’, used by scholars such as Joseph Nye,1 to argue that power in international relations is distributed like a ‘three-dimensional chessboard’ consisting of military power, economic power and transnational relations.
- Full Text:
- Date Issued: 2019
Activated carbon-decorated polyacrylonitrile fibers and their porphyrin-immobilized composites for removal of methylene blue dye and Ciprofloxacin in water
- Authors: Oyim, James , Amuhaya, Edith , Nyokong, Tebello
- Date: 2023
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:65077 , xlink:href="https://doi.org/10.1080/10601325.2023.2183868"
- Description: Photocatalyst adsorbents are an appealing group of materials for environmental applications. Herein, we study a new simple, inexpensive, yet very effective adsorbent photocatalyst based on porphyrin immobilized activated carbon-decorated polyacrylonitrile, InP(PAN/AC), for removal of methylene blue dye and Ciprofloxacin in water under Xe-lamp and sunlight irradiation (the latter for Ciprofloxacin only). Our results shed light on developing the most effective and sustainable adsorbent photocatalysts that can easily be industrialized due to the ease of preparation through electrospinning coupled with the readily available preparation materials. After five cycles, the InP(PAN/AC) maintained high methylene dye removal efficiency and structural integrity. Significantly, we propose the coordinated contribution of singlet oxygen and hydroxyl radical in the photodegradation process and highlight the importance of such an integrated system with adsorption and photodegradation capabilities for water treatment.
- Full Text:
- Date Issued: 2023
Creating the Ideal Push-Pull System for Electrocatalysis A Comparative Study on Symmetrical and Asymmetrical Cardanol-based Cobalt Phthalocyanines
- Authors: Nkhahle, Reitumetse , Nyokong, Tebello
- Date: 2021
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:44452 , xlink:href="https://doi.org/10.1002/elan.202060019"
- Description: A symmetrical cardanol-based cobalt phthalocyanine (Pc) along with its asymmetrical acid-based derivatives were synthesized and applied in the electrocatalysis of hydrazine. Despite the inhibition of electron movement by the bulky cardanol-based substituent throughout the series of molecules, an ideal combination of substituents was established in GCE-3 (2,9,16-tris(3- pentadecylphenoxy)-23-mono propionic acid phthalocyanato cobalt (II)) where a limit of detection (LoD) value of 5.10 μM (signal to noise ratio=5) was recorded for the detection of hydrazine. The results obtained serve as an illustration that the combination of electron-donating and electron-withdrawing substituents has a significant influence on the complete functioning of the phthalocyanine molecule(s) being investigated.
- Full Text:
- Date Issued: 2021
Interaction of nitric oxide with cobalt (II) phthalocyanine
- Authors: Vilakazi, Sibulelo L , Nyokong, Tebello
- Date: 1998
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293579 , vital:57100 , xlink:href="https://doi.org/10.1016/S0277-5387(98)00244-7"
- Description: The coordination of nitric oxide (NO) to cobalt(II) phthalocyanine (CoPc) in dimethyl sulphoxide (DMSO) has been studied. CoPc coordinates with NO in a 1:1 ratio, forming a CoPc(NO) species. The IR band observed at 1680 cm−1 is assigned to the coordinated NO. In the presence of excess NO, pseudo first order kinetics were followed. The observed rate constant, kf, was determined to be 15.0±0.3 dm−3 mol−1 s−1 and the equilibrium constant was K=5.4±0.4×104dm3 mol−1. Solution or adsorbed CoPc catalyses the reduction of NO. The products of reduction include NH3 and NH2OH.
- Full Text:
- Date Issued: 1998
Fluorescence “turn on” probe for bromide ion using nanoconjugates of glutathione-capped CdTe@ ZnS quantum dots with nickel tetraamino-phthalocyanine
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/190479 , vital:44998 , xlink:href="https://doi.org/10.1016/j.jphotochem.2013.05.013"
- Description: In this paper, three differently sized glutathione (GSH)-capped CdTe@ZnS quantum dots (QDs) have been successfully conjugated to nickel tetraamino-phthalocyanine (NiTAPc) to form different QDs-NiTAPc nanocomplexes. Several techniques such as TEM, FT-IR, time-resolved fluorescence measurement and electronic spectroscopy were employed to characterize the nanocomplex. Bromide ion was chosen as a model anion to test the efficacy of the nanoprobe. The fluorescence of the nanoconjugate was “turned off” upon binding but was progressively “turned on” upon interaction with varying concentrations of bromide ion. Experimental results showed that the quantum size effect of nanocrystal QD determined the overall sensitivity and selectivity of the nanoprobe and followed the order QD563-NiTAPc > QD605-NiTAPc > QD621-NiTAPc. The mechanism of reaction is proposed.
- Full Text:
- Date Issued: 2013
Selection and characterization of suitable lipid excipients for use in the manufacture of didanosine-loaded solid lipid nanoparticles and nanostructured lipid carriers
- Authors: Kasongo, Kasongo W , Pardeike, Jana , Muller, Rainer H , Walker, Roderick B
- Date: 2011
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184016 , vital:44156 , xlink:href="https://doi.org/10.1002/jps.22711"
- Description: This research aimed to evaluate the suitability of lipids for the manufacture of solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) loaded with the hydrophilic drug, didanosine (DDI). The crystalline state and polymorphism of lipids with the best‐solubulizing potential for DDI was investigated using differential scanning calorimetry (DSC) and wide‐angle X‐ray scattering (WAXS). DSC and WAXS were also used to determine potential interactions between the bulk lipids and DDI. Precirol® ATO 5 and Transcutol® HP showed the best‐solubilizing potential for DDI. Precirol® ATO 5 exists in the β‐modification before heating; however, a mixture of both α‐ and β‐modifications were detected following heating. Addition of Transcutol® HP to Precirol® ATO 5 changes the polymorphism of the latter from the β‐modification to a form that exhibits coexistence of the α‐ and β‐modifications. DDI exists in a crystalline state when dispersed at 5% (w/w) in Precirol® ATO 5 or in a Precirol® ATO 5/Transcutol® HP mixture. DSC and WAXS profiles of DDI/bulk lipids mixture obtained before and after exposure to heat revealed no interactions between DDI and the lipids. Precirol® ATO 5 and a mixture of Precirol® ATO 5 and Transcutol® HP may be used to manufacture DDI‐loaded SLN and NLC, respectively.
- Full Text:
- Date Issued: 2011
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.
- Full Text:
- Date Issued: 2008
Students as Agents of Social Change-Student Initiatives at Rhodes University, South Africa
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/386561 , vital:68151 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122830"
- Description: Rhodes University has a diversity of sustainable development initiatives meant for students and in a range of cases activities are initiated by students themselves with the support of the university. Results of a sustainability assessment revealed the involvement of students in environmental societies, environmental awareness campaigns, campus sustainability initiatives and community sustainability projects. Though most of the projects are still in their infancy and some challenges are yet to be overcome, the sustainability initiatives are gaining momentum and have contributed to improving the overall picture of sustainability at the university. Based on the results of the Rhodes University case study, the underpinning viewpoint in this paper is that university students are not merely recipients of Education for Sustainable Development but have the capacity to become agents for social change.
- Full Text:
- Date Issued: 2009
Melatonin alters the photodegradation of paracetamol
- Authors: Anoopkumar-Dukie, Shailendra , Glass, Beverley D , Walker, Roderick B , Daya, Santylal
- Date: 2000
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184357 , vital:44211 , xlink:href="https://doi.org/10.1211/146080800128735755"
- Description: The effects of melatonin, a known free-radical scavenger, on paracetamol in the presence of UV irradiation was studied by use of HPLC. The experiments were performed in air and nitrogen. The results show that the rate of photodegradation of melatonin is faster in air than in nitrogen whereas that of paracetamol is similar in air and nitrogen. When the two drugs were combined, melatonin retarded the degradation of paracetamol for up to 6h in the presence of nitrogen. However, in the presence of air melatonin rapidly enhances the photodegradation of paracetamol. This study shows that a combination of melatonin and paracetamol in the presence of air and UV irradiation can lead to rapid inactivation of both agents, thus raising important concerns about the possible use of melatonin as sunscreen
- Full Text:
- Date Issued: 2000
Photoreduction of tin (IV) phthalocyanines
- Authors: Nyokong, Tebello
- Date: 1994
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/293413 , vital:57083 , xlink:href="https://doi.org/10.1016/S0277-5387(00)83491-9"
- Description: Photolysis of Sn(IV)Pc(OH)2 (Pc = phthalocyanine dianion) and Sn(IV)Pc(Cl)2 using a tungsten lamp, and in the presence of SnCl2·2H2O as an electron donor results in the reduction of these complexes of π anion radical species. The reduction shows second order dependence on the concentration of the Sn(IV)Pc complexes and a first order dependence on SnCl2·H2O.
- Full Text:
- Date Issued: 1994
Synthesis, photophysical and nonlinear optical properties of microwave synthesized 4-tetra and octa-substituted lead phthalocyanines
- Authors: Modibane, Desmond K , Nyokong, Tebello
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/263452 , vital:53629 , xlink:href="https://doi.org/10.1016/j.poly.2009.03.013"
- Description: This work presents the photophysical and nonlinear optical behaviour of newly synthesized complexes: 2,(3)-tetrakis(4-benzyloxyphenoxyphthalocyaninato) lead (5a) and 2,3-octakis(4-benzyloxyphenoxyphthalocyaninato) lead (6a). The nonlinear optical behaviour of complexes 5a and 6a are compared with those of 2,(3)-tetraphenoxyphthalocyaninato lead (5b), 2,(3)-tetrakis(4-t-butylphenoxyphthalocyaninato) lead (5c), 2,3-octaphenoxyphthalocyaninato lead (6b) and 2,3-octakis(4-t-butylphenoxyphthalocyaninato) lead (6c). The synthesis of 5a and 6a was performed using microwave irradiation. Photophysical properties were studied for these complexes in 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 0.80 to 0.86 (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. Nonlinear optical properties were studied in dimethylsulfoxide. The optical limiting threshold intensity (Ilim) for the PbPc derivatives were calculated and ranged from 2.1 to 6.6 W/cm2.
- Full Text:
- Date Issued: 2009
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.
- Full Text:
- Date Issued: 2008
Voltammetric characterisation of the self-assembled monolayers (SAMs) of benzyl-and dodecyl-mercapto tetra substituted metallophthalocyanines complexes
- Authors: Agboola, Bolade , Westbroek, Philippe , Ozoemena, Kenneth I , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/281414 , vital:55723 , xlink:href="https://doi.org/10.1016/j.elecom.2006.08.047"
- Description: Voltammetric characterisations of cobalt, iron, manganese, nickel and zinc phthalocyanine complexes tetra substituted with benzyl- and dodecyl-mercapto ring substituents and immobilisation on gold electrodes via the self-assembling technique are presented. The self-assembled films are stable and showed blocking characteristics towards the following Faradaic processes; gold surface oxidation, under potential deposition of copper and solution redox chemistry of [Fe(H2O)6 3+ ]/[Fe(H2O)6 2+ ]. The solution chemistry of [Fe(CN)6]−3/[Fe(CN)6]−4 redox process was used to study the orientation of the CoPcs-SAMs and this revealed a possible deviation from flat orientation of the complexes on the gold electrodes when the SAM formation times were greater than 24 h. For SAM formation time at 24 and 48 h, CoTDMPc-SAM showed more inhibition of the [Fe(CN)6]−3/[Fe(CN)6]−4 redox process than the CoTBMPc-SAM counterpart, indicating more blocking characteristics of the dodecylmercapto ring substituents compared to the benzylmercapto counterpart. To avoid SAM desorption, the potential application should be limited to −0.2 to +0.8 V vs. Ag∣AgCl (NaCl, sat’d) in acidic and neutral pH.
- Full Text:
- Date Issued: 2007
Symmetry effect of cobalt phthalocyanines on the aluminium corrosion inhibition in hydrochloric acid
- Authors: Nnaji, Nnaemeka , Sen, Pinar , Nyokong, Tebello
- Date: 2022
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/231323 , vital:49877 , xlink:href="https://doi.org/10.1016/j.matlet.2021.130892"
- Description: The aluminium corrosion retardation potentials of phthalocyanine-based dyes, cobalt (II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (D1) and cobalt (II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (D2) in 1 M hydrochloric acid were evaluated. Results from potentiodynamic polarization measurements show that inhibition efficiency increased with inhibitor concentration at 28 °C with values of 91.9 % and 87.0 % values respectively for D1 and D2 at 10 μM.
- Full Text:
- Date Issued: 2022
More than just fields: Reframing deagrarianisation in landscapes and livelihoods
- Authors: Hebinck, Paul , Mtati, Nosiseko , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180322 , vital:43353 , xlink:href="https://doi.org/10.1016/j.jrurstud.2018.01.004"
- Description: This paper discusses the emergent properties of deagrarianisation processes in two villages in the central Eastern Cape, South Africa. The claim of is that much of the deagrarianisation literature and debate does not acknowledge the importance of landscapes and the interaction between their constituent elements, notably people, forests, grasslands, fields, grazing lands, open spaces, built environments and homesteads, all of which contribute to shaping and, in turn, are shaped by livelihoods. Conceptualising a landscape as a spatial entity and associated assemblage of practices, discourses and history, this paper dissects the landscape in terms of land uses for residential and cultural purposes, growing, grazing and gathering. These land use categories together represent the rural domain to which the villagers are attached as a place and a home. Their use of the land is not necessarily oriented to fully exploring its productive potential. The article explores the transformation from a productive landscape to one which largely hinges on consumption. The blurring of boundaries between the formally designated land use categories signifies the transformations occurring in many of the rural areas in the former homelands of South Africa.
- Full Text:
- Date Issued: 2018
Improved Photophysical and Photochemical Properties of Thiopheneethoxy Substituted Metallophthalocyanines on Immobilization onto Gold‐speckled Silica Nanoparticles
- Authors: Dube, Edith , Oluwole, David O , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187699 , vital:44688 , xlink:href="https://doi.org/10.1111/php.12879"
- Description: This work reports on the synthesis of tetrakis-[(thiophineethoxy) phthalocyaninato] indium(II) chloride (3). The photophysical behavior of complex 3 was compared to that of the Zn derivative (tetrakis-[(thiophineethoxy) phthalocyaninato] zinc(II) (complex 2)). The compounds were interacted with gold-speckled silica (GSS) nanoparticles via Au–S self assembly to afford the conjugates (2–GSS and 3–GSS). The photophysicochemical behavior of the compounds and their conjugates were assessed. The conjugates afforded a decrease in fluorescence quantum yields and lifetimes with improved triplet and singlet oxygen quantum yields in comparison with complexes 2 and 3 alone. The complexes and their conjugates could serve as good candidates for photodynamic therapy.
- Full Text:
- Date Issued: 2018