Comparative photophysicochemical behavior of nanoconjugates of indium tetracarboxyphenoxy phthalocyanines covalently linked to CdTe/ZnSe/ZnO quantum dots
- Oluwole, David O, Nyokong, Tebello
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7294 , http://hdl.handle.net/10962/d1020357 , http://dx.doi.org/10.1016/j.jphotochem.2015.07.009
- Description: This work reports on the photophysicochemical behavior of different nanoconjugates of core/shell/shell (GSH-CdTe/ZnSe/ZnO), core/shell (GSH-CdTe/ZnSe) and core (GSH-CdTe) (quantum dots QDs) with indium tetracarboxyphenoxy phthalocyanines ((OH)InTCPPc) in dimethylsulfoxide. The fluorescence quantum yields (Φf) and lifetimes (τf, in brackets) of QDs ranged from 0.20 (13.9 ns) to 0.42 (25.6 ns). The highest Φf value was obtained for GSH-CdTe/ZnSe/ZnO (4.5) while the least was observed in GSH-CdTe/ZnSe/ZnO (7.6), the numbers in brackets refer to the sizes. For (OH)InTCPPc alone a Φf and τf values of 0.02 and 2.43 ns, respectively were obtained. In the nanoconjugates, pivotal decrease in the Φf and τf of the QDs were observed with increase in the triplet and singlet oxygen quantum yields of (OH)InTCPPc. , Original publication is available at http://dx.doi.org/10.1016/j.jphotochem.2015.07.009
- Full Text: false
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7294 , http://hdl.handle.net/10962/d1020357 , http://dx.doi.org/10.1016/j.jphotochem.2015.07.009
- Description: This work reports on the photophysicochemical behavior of different nanoconjugates of core/shell/shell (GSH-CdTe/ZnSe/ZnO), core/shell (GSH-CdTe/ZnSe) and core (GSH-CdTe) (quantum dots QDs) with indium tetracarboxyphenoxy phthalocyanines ((OH)InTCPPc) in dimethylsulfoxide. The fluorescence quantum yields (Φf) and lifetimes (τf, in brackets) of QDs ranged from 0.20 (13.9 ns) to 0.42 (25.6 ns). The highest Φf value was obtained for GSH-CdTe/ZnSe/ZnO (4.5) while the least was observed in GSH-CdTe/ZnSe/ZnO (7.6), the numbers in brackets refer to the sizes. For (OH)InTCPPc alone a Φf and τf values of 0.02 and 2.43 ns, respectively were obtained. In the nanoconjugates, pivotal decrease in the Φf and τf of the QDs were observed with increase in the triplet and singlet oxygen quantum yields of (OH)InTCPPc. , Original publication is available at http://dx.doi.org/10.1016/j.jphotochem.2015.07.009
- Full Text: false
Physicochemical and photodynamic antimicrobial chemotherapy studies of mono- and tetra-pyridyloxy substituted indium(III) phthalocyanines
- Osifeko, Olawale L, Durmuş, Mahmut, Nyokong, Tebello
- Authors: Osifeko, Olawale L , Durmuş, Mahmut , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7255 , http://hdl.handle.net/10962/d1020264 , http://dx.doi.org/10.1016/j.jphotochem.2014.12.011
- Description: The synthesis and photophysicochemical properties of mono- and tetra-pyridyloxy substituted indium(III) phthalocyanines (InPcs) are presented in this study. General trends are described for quantum yields of fluorescence, triplet, singlet oxygen and photodegradation as well as lifetimes of fluorescence and triplet state of these compounds. The complexes exhibited high singlet oxygen quantum yields (ФΔ) ranging from 0.44 to 0.66 in DMF, and from 0.44 to 0.69 in DMSO and ФΔ = 0.31 for the quartenized tetra substituted InPc which is soluble in water. The triplet quantum yields (ФT) ranged from 0.77 to 0.95 in DMF and from 0.77 to 0.94) in DMSO. The tetra substituted photosensitizers do not differ in their inactivation of bacteria with over 8 log reduction of viable bacteria when compared with the mono substituted photosensitizer which could only manage a 1 log reduction. , Original publication is available at http://dx.doi.org/10.1016/j.jphotochem.2014.12.011
- Full Text: false
- Authors: Osifeko, Olawale L , Durmuş, Mahmut , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7255 , http://hdl.handle.net/10962/d1020264 , http://dx.doi.org/10.1016/j.jphotochem.2014.12.011
- Description: The synthesis and photophysicochemical properties of mono- and tetra-pyridyloxy substituted indium(III) phthalocyanines (InPcs) are presented in this study. General trends are described for quantum yields of fluorescence, triplet, singlet oxygen and photodegradation as well as lifetimes of fluorescence and triplet state of these compounds. The complexes exhibited high singlet oxygen quantum yields (ФΔ) ranging from 0.44 to 0.66 in DMF, and from 0.44 to 0.69 in DMSO and ФΔ = 0.31 for the quartenized tetra substituted InPc which is soluble in water. The triplet quantum yields (ФT) ranged from 0.77 to 0.95 in DMF and from 0.77 to 0.94) in DMSO. The tetra substituted photosensitizers do not differ in their inactivation of bacteria with over 8 log reduction of viable bacteria when compared with the mono substituted photosensitizer which could only manage a 1 log reduction. , Original publication is available at http://dx.doi.org/10.1016/j.jphotochem.2014.12.011
- Full Text: false
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
- Language: English
- Type: text , Article
- Identifier: vital:7266 , http://hdl.handle.net/10962/d1020275 , http://dx.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. , Original publication is available at http://dx.doi.org/10.1016/j.poly.2014.10.024
- Full Text: false
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7266 , http://hdl.handle.net/10962/d1020275 , http://dx.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. , Original publication is available at http://dx.doi.org/10.1016/j.poly.2014.10.024
- Full Text: false
The law of divorce and dissolution of life partnerships in South Africa: book review
- Authors: Kruuse, Helen
- Date: 2015
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54129 , vital:26394 , http://scholar.ufs.ac.za:8080/xmlui/handle/11660/2454
- Description: Jackie Heaton’s latest contribution to the family law domain is formidable – 777 pages of carefully crafted opinions and discussions of the law affecting divorce and dissolution of life partnerships. Given the range, diversity and depth of issues in this area, it is no wonder that she calls on those being among the best in their field to assist her in writing up the book.
- Full Text:
- Authors: Kruuse, Helen
- Date: 2015
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/54129 , vital:26394 , http://scholar.ufs.ac.za:8080/xmlui/handle/11660/2454
- Description: Jackie Heaton’s latest contribution to the family law domain is formidable – 777 pages of carefully crafted opinions and discussions of the law affecting divorce and dissolution of life partnerships. Given the range, diversity and depth of issues in this area, it is no wonder that she calls on those being among the best in their field to assist her in writing up the book.
- Full Text:
The relationship between concurrently measured SASS (South African Scoring System) and turbidity data archived in the South African River Health Programme’s Rivers Database
- Gordon, Andrew K, Griffin, Neil J, Palmer, Carolyn G
- Authors: Gordon, Andrew K , Griffin, Neil J , Palmer, Carolyn G
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7098 , http://hdl.handle.net/10962/d1015956
- Description: The need for monitoring the biological impacts of instream sediments has long been recognised, yet robust and scientifically defensible tools for doing so are still in the early stages of development because of the difficulties experienced by researchers in characterising the complicated mechanisms of biological effect elicited by sediment particles. Biological monitoring is one such tool, and this paper reports on the initial stages of a study to determine the most applicable approach for measuring the effects of instream sediments on aquatic macroinvertebrates in the South African context. In this first instance, the suitability of the rapid macroinvertebrate biomonitoring tool (the South African Scoring System) was investigated by determining the extent of the correlation between concurrently measured SASS metrics and turbidity data collected for the South African River Health Programme. All three SASS metrics – SASS score, number of taxa (NOT), and average score per taxon (ASPT) – were found to be significantly negatively correlated with turbidity, although variation in the data was high. Turbidity was found to be the major driver of change in ASPT. In contrast, electrical conductivity was the major driver of SASS scores and NOT, with turbidity a close second. When combined, electrical conductivity and turbidity accounted for 80 percent (SASS score) and 75 percent (NOT) of the variation in the regression model. Consequently, SASS metrics are a crude, but reliable, indicator of the negative biological implications of excessive instream sedimentation as measured by turbidity. A number of other potential biomonitoring approaches for detecting the impacts of fine sediment exposure are identified for further investigation: spatial analyses of macroinvertebrate assemblages; and the use of structural and functional metrics.
- Full Text:
- Authors: Gordon, Andrew K , Griffin, Neil J , Palmer, Carolyn G
- Date: 2015
- Language: English
- Type: text , Article
- Identifier: vital:7098 , http://hdl.handle.net/10962/d1015956
- Description: The need for monitoring the biological impacts of instream sediments has long been recognised, yet robust and scientifically defensible tools for doing so are still in the early stages of development because of the difficulties experienced by researchers in characterising the complicated mechanisms of biological effect elicited by sediment particles. Biological monitoring is one such tool, and this paper reports on the initial stages of a study to determine the most applicable approach for measuring the effects of instream sediments on aquatic macroinvertebrates in the South African context. In this first instance, the suitability of the rapid macroinvertebrate biomonitoring tool (the South African Scoring System) was investigated by determining the extent of the correlation between concurrently measured SASS metrics and turbidity data collected for the South African River Health Programme. All three SASS metrics – SASS score, number of taxa (NOT), and average score per taxon (ASPT) – were found to be significantly negatively correlated with turbidity, although variation in the data was high. Turbidity was found to be the major driver of change in ASPT. In contrast, electrical conductivity was the major driver of SASS scores and NOT, with turbidity a close second. When combined, electrical conductivity and turbidity accounted for 80 percent (SASS score) and 75 percent (NOT) of the variation in the regression model. Consequently, SASS metrics are a crude, but reliable, indicator of the negative biological implications of excessive instream sedimentation as measured by turbidity. A number of other potential biomonitoring approaches for detecting the impacts of fine sediment exposure are identified for further investigation: spatial analyses of macroinvertebrate assemblages; and the use of structural and functional metrics.
- Full Text:
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