A comparative study on the sensitive detection of hydroxyl radical using thiol-capped CdTe and CdTe/ZnS quantum dots
- Authors: Adegoke, Oluwasesan , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/242778 , vital:51077 , xlink:href="https://doi.org/10.1007/s10895-012-1089-2"
- Description: Four types of water-soluble luminescent quantum dots (QDs) whose surface was functionlaized with thioglycolic acid (TGA), 3-mercaptopropionic acid (MPA), or glutathione (GSH), were investigated for the sensitive and selective detection of hydroxyl radical (●OH) in aqueous media. It was found that the type of capping agent and QD influenced the sensitivity of the probe. The order of sensitivity of the probe was: GSH-CdTe@ZnS > MPA-CdTe@ZnS > TGA-CdTe > MPA-CdTe QDs. Under the optimum conditions, a limit of detection as low as 8.5 × 10-8 M was obtained using GSH-CdTe@ZnS. The effects of foreign reactive oxygen species and the Fenton reactants and products as possible interferences on the proposed probe were negligible for CdTe@ZnS QDs. Besides, experimental results indicated that CdTe@ZnS QDs were more attractive for the selective recognition of ●OH than CdTe QDs. The mechanistic reaction pathway between the QDs and ●OH is proposed.
- Full Text:
- Date Issued: 2012
Photophysical and photochemical studies of sulfur containing phthalocyanine derivatives in the presence of folic acid
- Authors: Nombona, Nolwazi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243180 , vital:51124 , xlink:href="https://doi.org/10.1016/j.ica.2012.03.051"
- Description: The syntheses of zinc and magnesium 9,16,23-tris-(5-trifluoromethyl-2-mercaptopyridine)-2-(carboxy)phthalocyaninato complexes are described for the first time. The photophysical and photochemical parameters of these molecules in the absence or presence of folic acid are compared to the corresponding oxygen bridged complexes and to 2,9,17,23-tetrakis-[(1,6-hexanedithiol)phthalocyaninato]zinc(II), [8,15,22-tris-(naptho)-2-(amidoethanethiol)phthalocyaninato]zinc(II) and zinc phthalocyanine tetrasulfonate. In the absence of folic acid, the complexes show relatively good triplet quantum yields (ranging from 0.52 to 0.88) in DMSO with reasonable triplet lifetime between 140 and 470 μs. The complexes showed high singlet oxygen quantum yield values ranging from 0.27 to 0.66 in the absence of folic acid. In the presence of folic acid, the triplet quantum yield values were between 0.37 and 0.75 and the lifetimes were significantly reduced (70–320 μs).
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- Date Issued: 2012
Photophysics and photochemistry of octaglucosylated zinc phthalocyanine derivatives
- Authors: Iqbal, Zafar , Ogunsipe, Abimbola , Nyokong, Tebello , Lyubimtsev, Alexey , Hanack, Michael , Ziegler, Thomas
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244416 , vital:51255 , xlink:href="https://doi.org/10.1142/S1088424612500630"
- Description: The ground state electronic absorption spectra, photophysics and photochemistry of amphiphilic octaglucosylated zinc phthalocyanines containing oxygen or sulfur bridges are presented. Triplet quantum yield values for the two dyes (in DMF and DMSO) vary between 0.71 and 0.84, while singlet quantum yield values lie between 0.63 and 0.75. Fluorescence lifetimes were determined experimentally by time correlated single photon counting and semi-empirically by fluorescence quenching techniques; and values from both methods were within the same range. Kinetic data were obtained for the quenching of the triplet state of the phthalocyanines by ground state molecular oxygen; the bimolecular collisional quenching rate constant range between 2.35 × 108 and 1.13 × 109 M-1.s-1. These values suggest that triplet states of the dyes are effectively quenched by ground molecular oxygen.
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- Date Issued: 2012
Electrospun polyacrylic acid polymer fibers functionalized with metallophthalocyanines for photosensitizing and gas sensing applications
- Authors: Zugle, Ruphino , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243543 , vital:51162 , xlink:href="https://doi.org/10.1080/10601325.2012.662006"
- Description: The photophysical and photochemical properties of tetraaminophthalocyanine complexes of lutetium and zinc covalently linked to polyacrylic acid were studied alongside those of unsubstituted zinc phthalocyanine within the same polymeric fiber matrix. All three phthalocyanines within the solid fiber matrices showed photoactivity by the generation of singlet oxygen as was observed in solution. The fluorescence behaviors of the composite fibers equally parallel those in solution. For the unsubstituted zinc phthalocyanine composite, the fiber showed fluorescence quenching on interaction with gaseous nitrogen dioxide similar to that in DMF and, thus could be a promising nanofabric material in developing optoelectronic devices that are responsive to the gas.
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- Date Issued: 2012
Lost in translation: Transformation in the first round of institutional audits
- Authors: McKenna, Sioux , Quinn, Lynn
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187384 , vital:44627 , xlink:href="https://hdl.handle.net/10520/EJC132752"
- Description: The South African higher education institutional audit process was introduced alongside similar endeavors internationally. However, despite many similarities, each country foregrounds different concerns within their higher education quality processes. In their seminal article, Harvey and Green suggest five possible notions of quality, one of which is quality as transformation, and in South Africa the message has been clearly stated: notions of quality are intricately related to transformation. Local research has however suggested that the notion of 'transformation' as quality takes on particular nuances within the country’s context. In the two institutional case studies presented here, the 'quality as transformation' discourse appears to have been largely lost in translation. In one university transformation was not called upon to construct notions of quality; quality was primarily constructed by a discourse of excellence. In the other institution, the transformation aspects of quality seem to have been interpreted in a particularly reductionist way as relating solely to racial demographics. In both cases, this article argues that the 'quality as transformation' discourse prevalent in the audit documentation in the South African context was lost somewhere between the intentions embodied in national documents and the processes embarked upon by institutions.
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- Date Issued: 2012
A study on the morphology of thin copper films on para-aramid yarns and their influence on the yarn’s electro-conductive and mechanical properties
- Authors: Schwarz, Anne , Hakuzimana, Jean , Westbroek, Philippe , Mey, Gilbert De , Priniotakis, Georgios , Nyokong, Tebello , Langenhove, Lieva Van
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243487 , vital:51157 , xlink:href="https://doi.org/10.1177/0040517511431291"
- Description: The latest technological advances in new materials and devices enabled wearable systems to be created by utilizing textile solutions. These solutions require electro-conductive yarns as a basic component. Although the production of electroconductive yarn is widely reported, research is still necessary to characterize them to advance their electro-conductive and mechanical properties. Hence, we served this need and characterized copper-coated para-aramid yarns produced by an in-house developed electroless deposition method. In this paper we present our investigation on the yarn’s copper layer characteristics after deposition. Furthermore, we looked, in depth, at the yarn’s electro-conductive properties before and after washing as well as their mechanical properties before and after copper deposition. We found a dependency of the copper layer morphology on its deposition time. This is directly correlated to the resulting layer thickness and hence to the yarn’s electro-conductive properties, demonstrating the autocatalytic nature of the coating process. Above that, the electro-conductive properties of the coated yarn linearly decrease with washing cycles. Furthermore, the copper coating impairs the yarn’s mechanical properties decreasing its specific stress at break by 30%.
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- Date Issued: 2012
Reverse saturation absorption spectra and optical limiting properties of chlorinated tetrasubstituted phthalocyanines containing different metals
- Authors: Tuhl, Ahmad , Manaa, Hacene , Makhseed, Saad , Al-Awadi, Nouria , Matthew, Jacob , Ibrahim, Hamada Mohamed , Nyokong, Tebello , Behbehani, Haider
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243498 , vital:51158 , xlink:href="https://doi.org/10.1016/j.optmat.2012.05.018"
- Description: A highly non-aggregated series of peripherally tetra(2,6-diisopropylphenoxy) substituted phthalocyanines (Pcs) containing different metals (Al, Ga, In and Zn) were prepared and their nonlinear optical properties (NLO), including the optical limiting behavior were investigated. This study explores the effect of the implanted metals along with the peripheral chlorine atoms on the NLO of the prepared complexes, thereby improving their optical limiting performance. The best wavelength at which the Pc complex exhibits the strongest nonlinear effect was determined over the low absorption window region (420–590 nm) comprised between the Q and B bands using a nanosecond pulsed laser with the aid of a Z-scan technique. The excited state absorption cross sections (σeff) have been found to be wavelength dependent with common double peaks at 505 nm and around 485 nm and the highest value was calculated for Pc1–In (1.1 × 10−16 cm2). The figure of merit spectra show different spectral structure when compared to the excited state absorption spectra and the largest figure of merit value was found to be around 107 for Pc1–In derivative. In full agreement with reverse saturation results, the optical limiting measurements, carried out at 485 nm and 532 nm for each derivative, show very low optical limiting thresholds at the former wavelength. In the continuous wave excitation regime, the Z-scan measurements, which were carried out at 632.8 and 532 nm, showed strong refractive and absorptive nonlinear effects.
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- Date Issued: 2012
The pump room
- Authors: Krueger, Anton
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225764 , vital:49256 , xlink:href="https://doi.org/10.1080/10137548.2012.754084"
- Description: I like Allan Kolski Horwitz. He’s done great things for independent publishing in South Africa. Through his company, Botsotso, he’s probably responsible for publishing more poetry, prose and drama than any single person in the country today. The industriousness of his one-man operation has generously sponsored and nurtured thousands of pages of local literature over the course of many years. This is why it makes me so uncomfortable to say that I really don’t like this play. It gives me no pleasure to write a negative review, and especially not about books written by people I like. If I hadn’t already committed myself to writing this review, I would have avoided it. Nevertheless, I had, so I won’t.
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- Date Issued: 2012
Higher education, academic communities, and the intellectual virtues
- Authors: Jones, Ward E
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/275647 , vital:55066 , xlink:href="https://doi.org/10.1111/edth.12005"
- Description: Because higher education brings members of academic communities in direct contact with students, the reflective higher education student is in an excellent position for developing two important intellectual virtues: confidence and humility. However, academic communities differ as to whether their members reach consensus, and their teaching practices reflect this difference. In this essay, Ward Jones argues that both consensus-reaching and non-consensus-reaching communities can encourage the development of intellectual confidence and humility in their students, although each will do so in very different ways.
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- Date Issued: 2012
Students’ navigation of the uncharted territories of academic writing
- Authors: Bharuthram, Sharita , McKenna, Sioux
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187373 , vital:44626 , xlink:href="https://doi.org/10.1080/18146627.2012.742651"
- Description: Many students enter tertiary education unfamiliar with the ‘norms and conventions’ of their disciplines. Research into academic literacies has shown that in order to succeed in their studies, students are expected to conform to these norms and conventions, which are often unrecognized or seen as ‘common sense’ by lecturers. Students have to develop their own ‘map’ of their programme’s expectations in order to make sense of the seemingly mysterious practices they are expected to take on. This study, undertaken at a University of Technology in South Africa, details students’ perceptions of their writing difficulties and their attempts to navigate their way through various writing tasks. The findings reveal that students experience a range of difficulties and that the students often feel unsupported in their travails with academic writing.
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- Date Issued: 2012
The use of hot and cold high pressure homogenization to enhance the loading capacity and encapsulation efficiency of nanostructured lipid carriers for the hydrophilic antiretroviral drug, didanosine for potential administration to paediatric patients
- Authors: Kasongo, Kasongo W , Müller, Rainer H , Walker, Roderick B
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184087 , vital:44170 , xlink:href="https://doi.org/10.3109/10837450.2010.542163"
- Description: A major obstacle to the application of nanostructured lipid carriers (NLCs) as carriers for hydrophilic drugs is the limited loading capacity (LC) and encapsulation efficiency (EE) of NLCs for these molecules. The purpose of this research was to design and implement a strategy to enhance the LC and EE of NLCs for the hydrophilic drug, didanosine (DDI). DDI was dispersed in Transcutol® HP and the particle size of DDI in the liquid lipid was reduced gradually using hot high pressure homogenization (HPH). The product obtained thereafter was added to Precirol® ATO 5 and the hot mixture was immediately dried using liquid nitrogen. The dried materials were then ground and passed through a 200 μm sieve and the solid lipid particles were dispersed in a surfactant solution and subsequently used to manufacture DDI-loaded NLCs using cold HPH. The LC and EE of NLCs for DDI manufactured using the new strategy were 3.39 ± 0.63% and 51.58 ± 1.31%, respectively, compared to 0.079 ± 0.001% and 32.45 ± 0.08%, respectively, obtained when DDI-loaded NLCs were produced using conventional hot HPH. The enhanced LC and EE for DDI make NLCs a potential technology for the oral administration of DDI to paediatric patients.
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- Date Issued: 2012
Photophysical and photochemical properties of novel phthalocyanines bearing non-peripherally substituted mercaptoquinoline moiety
- Authors: Yaşa, Göknur , Erdoğmuş, Ali , Uğur, Ahmet Lütf , Şener, M Kasım , Avcıata, Ulvi , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244360 , vital:51250 , xlink:href="https://doi.org/10.1142/S1088424612500940"
- Description: The synthesis, photophysical and photochemical properties of nonperipherally (a) mercaptoquinoline substituted Zn(II), TiO(IV) and Mg(II) and quaternized Zn(II) phthalocyanines are described for the first time. These complexes (2 to 5) and their precursor are characterized by elemental analysis, FT-IR, 1 H NMR, electronic spectroscopy as well as mass spectroscopy. Complexes 2, 4 and 5 have good solubility in organic solvents such as CHCl3, DCM, DMSO, DMF, THF and toluene and are not aggregated in all solvents within a wide concentration range. Complex 3 showed very good solubility in water as well as DMSO and DMF. General trends are described for singlet oxygen, photodegradation and fluorescence quantum yields of these complexes in DMSO and DMF. While complex 2 has higher singlet oxygen and fluorescence quantum yields than 3, 4 and 5, complex 4 has higher fluorescence quantum yields in DMF and DMSO than 2, 3 and 5. The effect of the solvents and metal on the photophysical and photochemical parameters of the metallophthalocyanines are also reported.
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- Date Issued: 2012
The photophysical and energy transfer behaviour of low symmetry phthalocyanine complexes conjugated to coreshell quantum dots
- Authors: Masilela, Nkosiphile , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243051 , vital:51111 , xlink:href="https://doi.org/10.1016/j.jphotochem.2012.07.016"
- Description: This work reports on the synthesis of new coreshell quantum dots (QDs)-low symmetry phthalocyanines conjugates. The energy transfer from QDs (donor) to phthalocyanines (acceptor) was investigated when the two are mixed together or chemically linked to each other. Ti monocarboxy phthalocyanine QDs-linked and Sn monocarboxy phthalocyanine QDs-linked gave the smallest centre-to-centre separation distance (r) corresponding to their higher Förster resonance energy transfer efficiencies which are estimated at 0.76 and 0.85 respectively. Higher energy transfer behaviour was achieved for all the covalently linked conjugates compared to their corresponding mixed counterparts. An improvement in triplet quantum yields and lifetimes was achieved for all the complexes in the presence of quantum dots, with the linked counterparts displaying excellent triplet state behaviour.
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- Date Issued: 2012
The use of response surface methodology in the evaluation of captopril microparticles manufactured using an oil in oil solvent evaporation technique
- Authors: Khamanga, Sandile M , Walker, Roderick B
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184221 , vital:44191 , xlink:href="https://doi.org/10.3109/02652048.2011.629744"
- Description: Captopril (CPT) microparticles were manufactured by solvent evaporation using acetone (dispersion phase) and liquid paraffin (manufacturing phase) with Eudragit® and Methocel® as coat materials. Design of experiments and response surface methodology (RSM) approaches were used to optimize the process. The microparticles were characterized based on the percent of drug released and yield, microcapsule size, entrapment efficiency and Hausner ratio. Differential scanning calorimetry (DSC), Infrared (IR) spectroscopy, scanning electron microscopy (SEM) and in vitro dissolution studies were conducted. The microcapsules were spherical, free-flowing and IR and DSC thermograms revealed that CPT was stable. The percent drug released was investigated with respect to Eudragit® RS and Methocel® K100M, Methocel® K15M concentrations and homogenizing speed. The optimal conditions for microencapsulation were 1.12 g Eudragit® RS, 0.67 g Methocel® K100M and 0.39 g Methocel® K15M at a homogenizing speed of 1643 rpm and 89% CPT was released. The value of RSM-mediated microencapsulation of CPT was elucidated.
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- Date Issued: 2012
Syntheses, protonation constants and antimicrobial activity of 2-substituted N-alkylimidazole derivatives
- Authors: Kleyi, Phumelele , Walmsley, Ryan S , Gundhla, Isaac Z , Walmsley, Tara A , Jauka, Tembisa I , Dames, Joanna F , Walker, Roderick B , Torto, Nelson , Tshentu, Zenixole R
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184066 , vital:44165 , xlink:href="https://www.ajol.info/index.php/sajc/article/view/123858"
- Description: A series of N-alkylimidazole-2-carboxylic acid, N-alkylimidazole-2-carboxaldehyde and N-alkylimidazole-2-methanol derivatives [alkyl = benzyl, methyl, ethyl, propyl, butyl, heptyl, octyl and decyl] have been synthesized and the protonation constants determined. The antimicrobial properties of the compounds were tested against Gram-negative (Escherichi coli), Gram-positive (Staphylococcus aureus and Bacillus subtilis subsp. spizizenii) bacterial strains and yeast (C. albicans). Both the disk diffusion and broth microdilution methods for testing the antimicrobial activity showed that N-alkylation of imidazole with longer alkyl chains and the substitution with low pKa group at 2-position resulted in enhanced antimicrobial activity. Particularly, the N-alkylimidazole-2-carboxylic acids exhibited the best antimicrobial activity due to the low pKa of the carboxylic acid moiety. Generally, all the N-alkylimidazole derivatives were most active against the Gram-positive bacteria [S. aureus (MIC = 5–160 µg mL–1) and B. subtilis subsp. spizizenii (5–20 µg mL–1)], with the latter more susceptible. All the compounds showed poor antimicrobial activity against both Gram-negative (E. coli, MIC = 0.15 to >2500 µg mL–1) bacteria and all the compounds were inactive against the yeast (Candida albicans).
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- Date Issued: 2012
The syntheses and photophysical properties of 4, 4′-isopropylidendioxydiphenyl substituted ball-type dinuclear Mg (II) and Zn (II) phthalocyanines
- Authors: Canlıca, Mevlüde , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/243554 , vital:51163 , xlink:href="https://doi.org/10.1016/j.poly.2011.10.024"
- Description: The syntheses of ball-type dinuclear Zn(II) and Mg(II) phthalocyanines containing four 4,4′-isopropylidendioxydiphenyl substituents at the peripheral and non-peripheral positions are presented. The structures of the synthesized compounds were characterized using elemental analyses, and UV–Vis, FT-IR, 1H NMR and mass spectroscopies. The ΦF values were 0.14, 0.11, 0.22, 0.15 and ΦT values were 0.84, 0.88, 0.62, 0.74, for 6–9, respectively. The largest triplet yields were observed for the non-peripherally substituted complexes 6 and 7, showing that non-peripheral substitution favors increased population of the triplet state. All complexes showed reasonably long triplet lifetimes with τT 510, 310, 910 and 350 μs in DMSO, respectively.
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- Date Issued: 2012
Comparison of carbon screen-printed and disk electrodes in the detection of antioxidants using CoPc derivatives
- Authors: Matemadombo, Fungisai , Apetrei, Constantin , Nyokong, Tebello , Rodríguez-Méndez, María Luz , de Saja, José Antonio
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244371 , vital:51251 , xlink:href="https://doi.org/10.1016/j.snb.2012.02.088"
- Description: Cobalt phthalocyanine (CoPc) and cobalt phthalocyanine carboxylic derivatives (CoTCPc and CoOCPc) have been used as electrocatalysts for the detection of the antioxidants vanillic acid, caffeic acid, pyrogallol, and ascorbic acid on screen-printed carbon and disk electrode surfaces. The cobalt phthalocyanines were used to detect vanillic acid (with limit of detection ranging from 1.15 μM to 2.42 μM at potentials of 0.55–0.88 V vs. Ag|AgCl), caffeic acid (with limit of detection ranging from 1.17 μM to 2.20 μM at potentials of 0.30–0.81 V vs. Ag|AgCl), pyrogallol (with limit of detection ranging from 1.16 μM to 3.63 μM at potentials of 0.52–0.63 V vs. Ag|AgCl), and ascorbic acid (with limit of detection ranging from 1.16 μM to 1.58 μM at potentials of 0.34–0.46 V vs. Ag|AgCl). The kinetic studies also demonstrate diffusion-controlled processes at the electrode surface. The SPCE electrodes have better detection properties towards vanillic acid, caffeic acid, pyrogallol while the disk electrodes had better ascorbic acid detection properties as proven by kinetic studies. Both types CoPc-influenced electrodes show 100% discrimination of the antioxidants.
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- Date Issued: 2012
Tetra and octa (2, 6-di-iso-propylphenoxy)-substituted phthalocyanines
- Authors: Tuhl, Ahmad , Chidawanayika, Wadzanai , Ibrahim, Hamada Mohamed , Al-Awadi, Nouria , Litwinski, Christian , Nyokong, Tebello , Behbehani, Haider , Manaa, Hacene , Makhseed, Saad
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/245855 , vital:51411 , xlink:href="https://doi.org/10.1142/S1088424612004495"
- Description: This work reports on the synthesis of novel metal free, zinc, aluminum, gallium and indium tetra and octa (2,6-di-iso-propylphenoxy)-substituted phthalocyanine derivatives. UV-visible and 1H NMR analyses confirm that a non-planar conformation, adapted by the phenoxy substituents due to steric interaction in both derivative series, perfectly discourage cofacial aggregation. Fluorescence quantum yields vary as a function of the number of substituents on the ring periphery, while the fluorescence lifetimes display no distinct trend. Triplet quantum yields are significantly larger for the tetra 2,6-di-iso-propylphenoxy- substituted derivatives relative to their corresponding octa-substituted species. However there was no overall trend in the triplet lifetime values. For almost all of the phthalocyanine derivatives, singlet oxygen was produced with relatively good quantum yields. This study explores the possibility of fine-tuning their physicochemical properties by simple structural modification.
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- Date Issued: 2012
Part II Zef/poor white kitsch chique
- Authors: Krueger, Anton
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/225745 , vital:49255 , xlink:href="https://doi.org/10.1080/17533171.2012.715484"
- Description: Ninja, who fronts the freak hip-hop band Die Antwoord, might not be quite what Desmond Tutu had in mind when he described South Africans as the “Rainbow People of God,”24 a happy harmonious amalgamation of different races. In his introduction to their seminal comic track “Enter the Ninja,” Ninja presents himself, rather, as a mongrel gutter dog, both embracing and parodying a syncretic fusion of the many different cultures and races of South Africa, celebrating as well as subverting the rainbow nation discourse. As he said in an interview with News24: “South African culture is quite a fucking fruit salad … a fucking fucked rainbow nation. South Africa's totally fucked … but in a cool way.”25 The cool side of being “fucked” in this way is “Zef.” Zef denotes a particular style of vulgar humor (in the usual sense of the word “vulgar,” but also with a nod to its origin in the Latin vulgaris for “mob” or “commoners”), which has been emerging more and more in South Africa during the past decade. It involves a way of presenting a persona in a purposefully degrading way, exaggerating one's appearance and mannerisms as low class, ill bred, and boorish. I would like to consider the recent popularity of “Zef” and examine its connection specifically to popular Afrikaans folk rock culture, a lineage of white poverty, and the feeling of disgrace experienced by many white Afrikaners after the end of apartheid.
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- Date Issued: 2012
CdTe quantum dots functionalized with 4-amino-2, 2, 6, 6-tetramethylpiperidine-N-oxide as luminescent nanoprobe for the sensitive recognition of bromide ion
- Authors: Adegoke, Oluwasesan , Hosten, Eric , McCleland, Cedric , Nyokong, Tebello
- Date: 2012
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/244393 , vital:51253 , xlink:href="https://doi.org/10.1016/j.aca.2012.01.040"
- Description: A novel bromide ion-selective modified nanoprobe sensor based on 4-amino-2,2,6,6-tetramethylpiperidine-N-oxide (4AT)-functionalized CdTe quantum dots (QDs-4AT) has been developed. Fluorescence quenching of the QDs by 4AT was observed. The functionalized QDs-4AT nanoprobe allowed a highly sensitive determination of bromide ion via analyte-induced change in the photoluminescence (fluorescence recovery) of the modified QDs. A detection limit of 0.6 nM of bromide ion was obtained, while the interfering effect of other inorganic cations and anions was investigated to examine the selectivity of the nanoprobe. The linear range was between 0.01 and 0.13 μM. Combined fluorescence lifetime and electron paramagnetic resonance measurements confirmed electron transfer processes between bromide ion and QDs-4AT.
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- Date Issued: 2012