Photophysical properties gallium octacarboxy phthalocyanines conjugated to CdSe@ ZnS quantum dots
- Tshangana, Charmaine, Nyokong, Tebello
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189055 , vital:44812 , xlink:href="https://doi.org/10.1016/j.saa.2015.06.086"
- Description: L-Glutathione (GSH) capped core CdSe (2.3 nm) and core shell CdSe@ZnS quantum dots (QDs) (3.0 nm and 3.5 nm) were coordinated to gallium octacarboxy phthalocyanine (ClGaPc(COOH)8) to form ClGaPc(COOH)8–QDs conjugates. An efficient transfer of energy from the QDs to the Pcs was demonstrated through Förster resonance energy transfer (FRET), the FRET efficiencies in all cases was above 50%. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were also determined for the conjugates. There was a decrease in the fluorescence lifetimes of ClGaPc(COOH)8 in the presence of all the QDs, due to the heavy atom effect. The triplet quantum yields increased in the conjugates. The lifetimes also became longer for the conjugates compared to Pc alone.
- Full Text:
- Date Issued: 2015
- Authors: Tshangana, Charmaine , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189055 , vital:44812 , xlink:href="https://doi.org/10.1016/j.saa.2015.06.086"
- Description: L-Glutathione (GSH) capped core CdSe (2.3 nm) and core shell CdSe@ZnS quantum dots (QDs) (3.0 nm and 3.5 nm) were coordinated to gallium octacarboxy phthalocyanine (ClGaPc(COOH)8) to form ClGaPc(COOH)8–QDs conjugates. An efficient transfer of energy from the QDs to the Pcs was demonstrated through Förster resonance energy transfer (FRET), the FRET efficiencies in all cases was above 50%. The photophysical parameters (triplet state and fluorescence quantum yields and lifetimes) were also determined for the conjugates. There was a decrease in the fluorescence lifetimes of ClGaPc(COOH)8 in the presence of all the QDs, due to the heavy atom effect. The triplet quantum yields increased in the conjugates. The lifetimes also became longer for the conjugates compared to Pc alone.
- Full Text:
- Date Issued: 2015
Photophysical properties of zinc phthalocyanine–uridine single walled carbon nanotube–conjugates
- Ogbodu, Rachael O, Amuhaya, Edith K, Mashazi, Philani N, Nyokong, Tebello
- Authors: Ogbodu, Rachael O , Amuhaya, Edith K , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193586 , vital:45350 , xlink:href="https://doi.org/10.1016/j.saa.2015.04.040"
- Description: The photophysical properties of the conjugate of uridine and zinc mono carboxy phenoxy phthalocyanine (ZnMCPPc–uridine, 4) are reported in this work. The conjugate was also adsorbed onto single walled carbon nanotubes (ZnMCPPc–uridine–SWCNT, 5). The X-ray photoelectron spectroscopy of 4 showed three N 1s peaks while that of 5 showed four N 1s peak, a new peak at 399.4 eV of 5 was assigned to pyrrolidonic nitrogen, due to the interaction of the pyrrolic nitrogen of 4 with the oxygen moiety of SWCNT–COOH in 5. The triplet lifetime, triplet and singlet oxygen quantum yields of the zinc mono carboxy phenoxy phthalocyanine increased by over 40% in the presence of uridine. SWCNTs resulted in only a small quenching of the triplet state parameters of 4.
- Full Text:
- Date Issued: 2015
- Authors: Ogbodu, Rachael O , Amuhaya, Edith K , Mashazi, Philani N , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/193586 , vital:45350 , xlink:href="https://doi.org/10.1016/j.saa.2015.04.040"
- Description: The photophysical properties of the conjugate of uridine and zinc mono carboxy phenoxy phthalocyanine (ZnMCPPc–uridine, 4) are reported in this work. The conjugate was also adsorbed onto single walled carbon nanotubes (ZnMCPPc–uridine–SWCNT, 5). The X-ray photoelectron spectroscopy of 4 showed three N 1s peaks while that of 5 showed four N 1s peak, a new peak at 399.4 eV of 5 was assigned to pyrrolidonic nitrogen, due to the interaction of the pyrrolic nitrogen of 4 with the oxygen moiety of SWCNT–COOH in 5. The triplet lifetime, triplet and singlet oxygen quantum yields of the zinc mono carboxy phenoxy phthalocyanine increased by over 40% in the presence of uridine. SWCNTs resulted in only a small quenching of the triplet state parameters of 4.
- Full Text:
- Date Issued: 2015
Photophysical studies of newly derivatized mono substituted phthalocyanines grafted onto silica nanoparticles via click chemistry
- Fashina, Adedayo, Amuhaya, Edith, Nyokong, Tebello
- Authors: Fashina, Adedayo , Amuhaya, Edith , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189537 , vital:44855 , xlink:href="https://doi.org/10.1016/j.saa.2014.12.070"
- Description: This work reports on the synthesis, characterization and photophysical studies of newly derived phthalocyanine complexes and the phthalocyanine–silica nanoparticles conjugates. The derived phthalocyanine complexes have one terminal alkyne group. The derived phthalocyanine complexes showed improved photophysical properties (ФF, ФT, ΦΔ and τT) compared to the respective phthalocyanine complexes from which they were derived. The derived phthalocyanine complexes were conjugated to the surface of an azide functionalized silica nanoparticles via copper (1) catalyzed cyclo-addition reaction. All the conjugates showed lower triplet quantum yields ranging from 0.37 to 0.44 compared to the free phthalocyanine complexes. The triplet lifetimes ranged from 352 to 484 μs for the conjugates and from 341 to 366 μs for the free phthalocyanine complexes.
- Full Text:
- Date Issued: 2015
- Authors: Fashina, Adedayo , Amuhaya, Edith , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189537 , vital:44855 , xlink:href="https://doi.org/10.1016/j.saa.2014.12.070"
- Description: This work reports on the synthesis, characterization and photophysical studies of newly derived phthalocyanine complexes and the phthalocyanine–silica nanoparticles conjugates. The derived phthalocyanine complexes have one terminal alkyne group. The derived phthalocyanine complexes showed improved photophysical properties (ФF, ФT, ΦΔ and τT) compared to the respective phthalocyanine complexes from which they were derived. The derived phthalocyanine complexes were conjugated to the surface of an azide functionalized silica nanoparticles via copper (1) catalyzed cyclo-addition reaction. All the conjugates showed lower triplet quantum yields ranging from 0.37 to 0.44 compared to the free phthalocyanine complexes. The triplet lifetimes ranged from 352 to 484 μs for the conjugates and from 341 to 366 μs for the free phthalocyanine complexes.
- Full Text:
- Date Issued: 2015
Photophysicochemical properties and in vitro cytotoxicity of zinc tetracarboxyphenoxy phthalocyanine–quantum dot nanocomposites
- Oluwole, David O, Tilbury, Chelsea M, Prinsloo, Earl, Limson, Janice L, Nyokong, Tebello
- Authors: Oluwole, David O , Tilbury, Chelsea M , Prinsloo, Earl , Limson, Janice L , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240846 , vital:50878 , xlink:href="https://doi.org/10.1016/j.poly.2015.12.060"
- Description: Cadmium based quantum dots (QDs) capped with two different ligands (thioglycolic acid, TGA, and glutathione, GSH) were synthesized. The QDs are: CdTe, CdTe/ZnO, CdTeSe, CdTeSe/ZnO and CdSe/ZnS (the last one for TGA only). Cytotoxicity of the QDs against MCF-7 epithelial breast cancer was evaluated. The TGA capped core QDs were found to be highly cytotoxic to the cell lines when compared to GSH capped ones. The glutathione capped QDs were covalently linked to zinc tetracarboxyphenoxy phthalocyanine (ZnTCPPc). Cytotoxicity and photophysicochemical properties of the conjugates were investigated. The toxicity of the core QDs was reduced in the presence of ZnTCPPc. Enhanced triplet quantum yields and long triplet lifetimes were obtained for ZnTCPPc in the presence of all QDs.
- Full Text:
- Date Issued: 2015
- Authors: Oluwole, David O , Tilbury, Chelsea M , Prinsloo, Earl , Limson, Janice L , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/240846 , vital:50878 , xlink:href="https://doi.org/10.1016/j.poly.2015.12.060"
- Description: Cadmium based quantum dots (QDs) capped with two different ligands (thioglycolic acid, TGA, and glutathione, GSH) were synthesized. The QDs are: CdTe, CdTe/ZnO, CdTeSe, CdTeSe/ZnO and CdSe/ZnS (the last one for TGA only). Cytotoxicity of the QDs against MCF-7 epithelial breast cancer was evaluated. The TGA capped core QDs were found to be highly cytotoxic to the cell lines when compared to GSH capped ones. The glutathione capped QDs were covalently linked to zinc tetracarboxyphenoxy phthalocyanine (ZnTCPPc). Cytotoxicity and photophysicochemical properties of the conjugates were investigated. The toxicity of the core QDs was reduced in the presence of ZnTCPPc. Enhanced triplet quantum yields and long triplet lifetimes were obtained for ZnTCPPc in the presence of all QDs.
- Full Text:
- Date Issued: 2015
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
- Date Issued: 2015
- 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
- Date Issued: 2015
Physicochemical and photodynamic antimicrobial chemotherapy studies of mono-and tetra-pyridyloxy substituted indium (III) phthalocyanines
- Osifeko, Olawale, Durmus, Mahmut, Nyokong, Tebello
- Authors: Osifeko, Olawale , Durmus, Mahmut , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189547 , vital:44856 , xlink:href="https://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.
- Full Text:
- Date Issued: 2015
- Authors: Osifeko, Olawale , Durmus, Mahmut , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189547 , vital:44856 , xlink:href="https://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.
- Full Text:
- Date Issued: 2015
Physicochemical behavior of nanohybrids of mono and tetra substituted carboxyphenoxy phthalocyanine covalently linked to GSH–CdTe/CdS/ZnS quantum dots
- Oluwole, David O, Nyokong, Tebello
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- 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
- Date Issued: 2015
- 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
- Date Issued: 2015
Physicochemical behavior of nanohybrids of mono and tetra substituted carboxyphenoxy phthalocyanine covalently linked to GSH–CdTe/CdS/ZnS quantum dots
- Oluwole, David O, Nyokong, Tebello
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189480 , vital:44850 , xlink:href="https://doi.org/10.1016/j.poly.2014.10.024"
- Description: Zinc monocarboxyphenoxy and tetracarboxyphenoxy phthalocyanines were covalently linked with three different sizes of glutathione capped core/shell/shell {CdTe/CdS/ZnS(4.2), CdTe/CdS/ZnS(5.1) and CdTe/CdS/ZnS(6.7)}; a core shell {CdTe/CdS(3.1)} and core {CdTe(2.4)} quantum dots. The physicochemical behavior and Förster resonance energy transfer (FRET) processes of the nanohybrids were investigated. The highest FRET efficiency was observed with CdTe/CdS/ZnS(6.7) nanohybrids with 98% and the least efficiency was observed with CdTe(2.4) nanohybrids with 85%. The CdTe/CdS/ZnS(6.7) also showed the best physicochemical behavior. These good physicochemical properties make the synthesized nanohybrids viable photosensitizers.
- Full Text:
- Date Issued: 2015
- Authors: Oluwole, David O , Nyokong, Tebello
- Date: 2015
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/189480 , vital:44850 , xlink:href="https://doi.org/10.1016/j.poly.2014.10.024"
- Description: Zinc monocarboxyphenoxy and tetracarboxyphenoxy phthalocyanines were covalently linked with three different sizes of glutathione capped core/shell/shell {CdTe/CdS/ZnS(4.2), CdTe/CdS/ZnS(5.1) and CdTe/CdS/ZnS(6.7)}; a core shell {CdTe/CdS(3.1)} and core {CdTe(2.4)} quantum dots. The physicochemical behavior and Förster resonance energy transfer (FRET) processes of the nanohybrids were investigated. The highest FRET efficiency was observed with CdTe/CdS/ZnS(6.7) nanohybrids with 98% and the least efficiency was observed with CdTe(2.4) nanohybrids with 85%. The CdTe/CdS/ZnS(6.7) also showed the best physicochemical behavior. These good physicochemical properties make the synthesized nanohybrids viable photosensitizers.
- Full Text:
- Date Issued: 2015
Planning for the future: mapping anticipated environmental and social impacts in a nascent tourism destination
- Aswani, Shankar, Diedrich, Amy, Currier, Kitty
- Authors: Aswani, Shankar , Diedrich, Amy , Currier, Kitty
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145415 , vital:38436 , DOI: 10.1080/08941920.2015.1020582
- Description: Tourism is a significant driver of social and ecological change in developing countries, particularly in small-island states, which are susceptible to tourism impacts due to their particular social and environmental characteristics. In this article we present a participatory mapping approach to obtaining spatially explicit local perceptions of future environmental and social change resulting from tourism development, as well as addressing the different community conflicts that may arise through the introduction of tourism in the future in a Solomon Islands community. The results show that spatial conflicts within a community over territory and associated resources are likely to occur when designing natural resource management and tourism development plans. This knowledge can help us increase the future sustainability of tourism in nascent small-islands destinations, particularly in vulnerable regions such as Roviana, which have experienced very little tourism development and will likely experience more in the near future.
- Full Text:
- Date Issued: 2015
- Authors: Aswani, Shankar , Diedrich, Amy , Currier, Kitty
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145415 , vital:38436 , DOI: 10.1080/08941920.2015.1020582
- Description: Tourism is a significant driver of social and ecological change in developing countries, particularly in small-island states, which are susceptible to tourism impacts due to their particular social and environmental characteristics. In this article we present a participatory mapping approach to obtaining spatially explicit local perceptions of future environmental and social change resulting from tourism development, as well as addressing the different community conflicts that may arise through the introduction of tourism in the future in a Solomon Islands community. The results show that spatial conflicts within a community over territory and associated resources are likely to occur when designing natural resource management and tourism development plans. This knowledge can help us increase the future sustainability of tourism in nascent small-islands destinations, particularly in vulnerable regions such as Roviana, which have experienced very little tourism development and will likely experience more in the near future.
- Full Text:
- Date Issued: 2015
Plasmodium falciparum Hop: detailed analysis on complex formation with Hsp70 and Hsp90
- Hatherley, Rowan, Clitheroe, Crystal-Leigh, Faya, Ngonidzashe, Tastan Bishop, Özlem
- Authors: Hatherley, Rowan , Clitheroe, Crystal-Leigh , Faya, Ngonidzashe , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163532 , vital:41046 , https://doi.org/10.1016/j.bbrc.2014.11.103
- Description: The heat shock organizing protein (Hop) is important in modulating the activity and co-interaction of two chaperones: heat shock protein 70 and 90 (Hsp70 and Hsp90). Recent research suggested that Plasmodium falciparum Hop (PfHop), PfHsp70 and PfHsp90 form a complex in the trophozoite infective stage. However, there has been little computational research on the malarial Hop protein in complex with other malarial Hsps.
- Full Text:
- Date Issued: 2015
- Authors: Hatherley, Rowan , Clitheroe, Crystal-Leigh , Faya, Ngonidzashe , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163532 , vital:41046 , https://doi.org/10.1016/j.bbrc.2014.11.103
- Description: The heat shock organizing protein (Hop) is important in modulating the activity and co-interaction of two chaperones: heat shock protein 70 and 90 (Hsp70 and Hsp90). Recent research suggested that Plasmodium falciparum Hop (PfHop), PfHsp70 and PfHsp90 form a complex in the trophozoite infective stage. However, there has been little computational research on the malarial Hop protein in complex with other malarial Hsps.
- Full Text:
- Date Issued: 2015
Plasmodium falciparum Hop: detailed analysis on complex formation with Hsp70 and Hsp90
- Hatherley, Rowan, Clitheroe, Crystal-Leigh, Faya, Ngonidzashe, Tastan Bishop, Özlem
- Authors: Hatherley, Rowan , Clitheroe, Crystal-Leigh , Faya, Ngonidzashe , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125708 , vital:35810 , https://doi.10.1016/j.bbrc.2014.11.103
- Description: The heat shock organizing protein (Hop) is important in modulating the activity and co-interaction of two chaperones: heat shock protein 70 and 90 (Hsp70 and Hsp90). Recent research suggested that Plasmodium falciparum Hop (PfHop), PfHsp70 and PfHsp90 form a complex in the trophozoite infective stage. However, there has been little computational research on the malarial Hop protein in complex with other malarial Hsps. Using in silico characterization of the protein, this work showed that individual domains of Hop are evolving at different rates within the protein. Differences between human Hop (HsHop) and PfHop were identified by motif analysis. Homology modeling of PfHop and HsHop in complex with their own cytosolic Hsp90 and Hsp70 C-terminal peptide partners indicated excellent conservation of the Hop concave TPR sites bound to the C-terminal motifs of partner proteins. Further, we analyzed additional binding sites between Hop and Hsp90, and showed, for the first time, that they are distinctly less conserved between human and malaria parasite. These sites are located on the convex surface of Hop TPR2, and involved in interactions with the Hsp90 middle domain. Since the convex sites are less conserved than the concave sites, it makes their potential for malarial inhibitor design extremely attractive (as opposed to the concave sites which have been the focus of previous efforts).
- Full Text:
- Date Issued: 2015
- Authors: Hatherley, Rowan , Clitheroe, Crystal-Leigh , Faya, Ngonidzashe , Tastan Bishop, Özlem
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125708 , vital:35810 , https://doi.10.1016/j.bbrc.2014.11.103
- Description: The heat shock organizing protein (Hop) is important in modulating the activity and co-interaction of two chaperones: heat shock protein 70 and 90 (Hsp70 and Hsp90). Recent research suggested that Plasmodium falciparum Hop (PfHop), PfHsp70 and PfHsp90 form a complex in the trophozoite infective stage. However, there has been little computational research on the malarial Hop protein in complex with other malarial Hsps. Using in silico characterization of the protein, this work showed that individual domains of Hop are evolving at different rates within the protein. Differences between human Hop (HsHop) and PfHop were identified by motif analysis. Homology modeling of PfHop and HsHop in complex with their own cytosolic Hsp90 and Hsp70 C-terminal peptide partners indicated excellent conservation of the Hop concave TPR sites bound to the C-terminal motifs of partner proteins. Further, we analyzed additional binding sites between Hop and Hsp90, and showed, for the first time, that they are distinctly less conserved between human and malaria parasite. These sites are located on the convex surface of Hop TPR2, and involved in interactions with the Hsp90 middle domain. Since the convex sites are less conserved than the concave sites, it makes their potential for malarial inhibitor design extremely attractive (as opposed to the concave sites which have been the focus of previous efforts).
- Full Text:
- Date Issued: 2015
Politics and discourse in South Africa:
- Authors: Hunt, Sally
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/139249 , vital:37719 , ISBN 9789027206565 , https://benjamins.com/catalog/dapsac.65
- Description: The discourses of the post-apartheid South Africa embody symbols of change and promises of new lessons in history. This is the first volume that brings together analyses of a variety of discourses produced in South Africa through which we follow the evolution of transitional processes in the country’s political institutions and in the opinions of its populace. The book offers to the reader a visit to the Parliament, a peek into the internet forums, analyses of the country's official papers and speeches, and the media accounts. Through all these discourses we see the burning questions – "Who Are We Now?" and "Who Do We Want To Be?" – being repetitively examined and identities cross-formed while the country deals with new, post-apartheid challenges, as well as successes.
- Full Text:
- Date Issued: 2015
- Authors: Hunt, Sally
- Date: 2015
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/139249 , vital:37719 , ISBN 9789027206565 , https://benjamins.com/catalog/dapsac.65
- Description: The discourses of the post-apartheid South Africa embody symbols of change and promises of new lessons in history. This is the first volume that brings together analyses of a variety of discourses produced in South Africa through which we follow the evolution of transitional processes in the country’s political institutions and in the opinions of its populace. The book offers to the reader a visit to the Parliament, a peek into the internet forums, analyses of the country's official papers and speeches, and the media accounts. Through all these discourses we see the burning questions – "Who Are We Now?" and "Who Do We Want To Be?" – being repetitively examined and identities cross-formed while the country deals with new, post-apartheid challenges, as well as successes.
- Full Text:
- Date Issued: 2015
Polyurethane composite adsorbent using solid phase extraction method for preconcentration of metal ion from aqueous solution
- Olorundare, O F, Msagati, T A M, Okonkwo, J O, Krause, Rui W M, Mamba, Bhekie B
- Authors: Olorundare, O F , Msagati, T A M , Okonkwo, J O , Krause, Rui W M , Mamba, Bhekie B
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125386 , vital:35778 , https://doi.org/10.1007/s13762-014-0645-5
- Description: Polyurethane composite adsorbent polymeric material was prepared and investigated for selected solid-phase extraction for metal ions, prior to its determination by inductively coupled plasma optical emission spectrometry. The surface characterisation was done using Fourier transform infrared spectroscopy. The separation and preconcentration conditions of the analytes investigated includes influence of pH, sample loading flow rate, elution flow rate, type and concentration of eluents. The optimum pH for the highest efficient recoveries for all metal ions, which ranged from 70 to 85 %, is pH 7. The metal ions were quantitatively eluted with 5 mL of 2 mol/L HNO3. Common coexisting ions did not interfere with the separation. The percentage recovery of the metal ions ranged between 70 and 89 %, while the results for the limit of detection and limit of quantification ranged from 0.249 to 0.256 and 0.831 to 0.855, respectively. The experimental tests showed good preconcentration results of trace levels of metal ions using synthesised polyurethane polymer adsorbent composite.
- Full Text:
- Date Issued: 2015
- Authors: Olorundare, O F , Msagati, T A M , Okonkwo, J O , Krause, Rui W M , Mamba, Bhekie B
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125386 , vital:35778 , https://doi.org/10.1007/s13762-014-0645-5
- Description: Polyurethane composite adsorbent polymeric material was prepared and investigated for selected solid-phase extraction for metal ions, prior to its determination by inductively coupled plasma optical emission spectrometry. The surface characterisation was done using Fourier transform infrared spectroscopy. The separation and preconcentration conditions of the analytes investigated includes influence of pH, sample loading flow rate, elution flow rate, type and concentration of eluents. The optimum pH for the highest efficient recoveries for all metal ions, which ranged from 70 to 85 %, is pH 7. The metal ions were quantitatively eluted with 5 mL of 2 mol/L HNO3. Common coexisting ions did not interfere with the separation. The percentage recovery of the metal ions ranged between 70 and 89 %, while the results for the limit of detection and limit of quantification ranged from 0.249 to 0.256 and 0.831 to 0.855, respectively. The experimental tests showed good preconcentration results of trace levels of metal ions using synthesised polyurethane polymer adsorbent composite.
- Full Text:
- Date Issued: 2015
Precocious little monsters and the birth of puberty science: tracing early puberty as a health matter
- Pinto, Pedro, Macleod, Catriona I
- Authors: Pinto, Pedro , Macleod, Catriona I
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143626 , vital:38268 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Over the last two decades, early puberty has been increasingly portrayed in scientific and popular arenas as an alarming health issue. Changes in pubertal timing are frequently accorded a range of medical and moral dangers, suggesting individual degeneracy and social crisis. In our presentation – the first output of a Foucauldian genealogical investigation on pubertal knowledge in medical journals – we show that today’s problematisations of early puberty are rooted in the figure of the child monster, as produced in early nineteenth century medical discourse. Drawing on doctors’ clinical encounters with the pubescent body as represented in medical journals during that period, we argue that puberty, understood as a scientific construct, has been ‘praecox’ since the beginning. From this genealogical viewpoint, we explore the ways in which our present ‘pubertal complex’ talks to an old medical dilemma: the confusion of maturity and immaturity within the young body.
- Full Text:
- Date Issued: 2015
- Authors: Pinto, Pedro , Macleod, Catriona I
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143626 , vital:38268 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Over the last two decades, early puberty has been increasingly portrayed in scientific and popular arenas as an alarming health issue. Changes in pubertal timing are frequently accorded a range of medical and moral dangers, suggesting individual degeneracy and social crisis. In our presentation – the first output of a Foucauldian genealogical investigation on pubertal knowledge in medical journals – we show that today’s problematisations of early puberty are rooted in the figure of the child monster, as produced in early nineteenth century medical discourse. Drawing on doctors’ clinical encounters with the pubescent body as represented in medical journals during that period, we argue that puberty, understood as a scientific construct, has been ‘praecox’ since the beginning. From this genealogical viewpoint, we explore the ways in which our present ‘pubertal complex’ talks to an old medical dilemma: the confusion of maturity and immaturity within the young body.
- Full Text:
- Date Issued: 2015
Preface: proceedings of the 13th IASWS international conference
- Foster, Ian, Rowntree, Kate M, Ellery, William F N, Ogrinc, Nives, Oldham, Carolyn
- Authors: Foster, Ian , Rowntree, Kate M , Ellery, William F N , Ogrinc, Nives , Oldham, Carolyn
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144465 , vital:38348 , DOI 10.1007/s11368-015-1276-2
- Description: Rhodes University, Grahamstown, South Africa, was the venue for the 13th IASWS International Conference, held from 15 to 18 July, 2014. This international meeting built upon and expanded developing research in South Africa on sediment processes and followed on from a successful meeting organized by Rowntree and Foster on behalf of the Southern African Association of Geomorphologists (SAAG) held in Grahamstown in 2010 and the publication of a special issue of the journal Land Degradation and Development edited by Rowntree et al. (2012).
- Full Text:
- Date Issued: 2015
- Authors: Foster, Ian , Rowntree, Kate M , Ellery, William F N , Ogrinc, Nives , Oldham, Carolyn
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144465 , vital:38348 , DOI 10.1007/s11368-015-1276-2
- Description: Rhodes University, Grahamstown, South Africa, was the venue for the 13th IASWS International Conference, held from 15 to 18 July, 2014. This international meeting built upon and expanded developing research in South Africa on sediment processes and followed on from a successful meeting organized by Rowntree and Foster on behalf of the Southern African Association of Geomorphologists (SAAG) held in Grahamstown in 2010 and the publication of a special issue of the journal Land Degradation and Development edited by Rowntree et al. (2012).
- Full Text:
- Date Issued: 2015
Preliminary evidence for the organisation of a bacterial community by zooplanktivores at the top of an estuarine planktonic food web
- Wasserman, Ryan J, Matcher, Gwynneth F, Vink, Tim J F, Froneman, P William
- Authors: Wasserman, Ryan J , Matcher, Gwynneth F , Vink, Tim J F , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68237 , vital:29222 , https://doi.org/10.1007/s00248-014-0505-3
- Description: Publisher version , As part of a larger investigation, the effect of apex predation on estuarine bacterial community structure, through trophic cascading, was investigated using experimental in situ mesocosms. Through either the removal (filtration) or addition of specific size classes of planktonic groups, four different trophic scenarios were established using estuarine water and its associated plankton. One such treatment represented a “natural” scenario in which stable apex predatory pressure was qualified. Water samples were collected over time from each of the treatments for bacterial community evaluation. These samples were assessed through pyrosequencing of the variable regions 4 and 5 of the bacterial 16S rRNA gene and analysed at the species operational taxonomic unit (OTU) level using a community procedure. The blue-green group dominated the samples, followed by Proteobacteria and Bacteroidetes. Samples were the most similar among treatments at the commencement of the experiment. While the bacterial communities sampled within each treatment changed over time, the deviation from initial appeared to be linked to the treatment trophic scenarios. The least temporal deviation-from-initial in bacterial community was found within the stable apex predatory pressure treatment. These findings are consistent with trophic cascade theory, whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity.
- Full Text: false
- Date Issued: 2015
- Authors: Wasserman, Ryan J , Matcher, Gwynneth F , Vink, Tim J F , Froneman, P William
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68237 , vital:29222 , https://doi.org/10.1007/s00248-014-0505-3
- Description: Publisher version , As part of a larger investigation, the effect of apex predation on estuarine bacterial community structure, through trophic cascading, was investigated using experimental in situ mesocosms. Through either the removal (filtration) or addition of specific size classes of planktonic groups, four different trophic scenarios were established using estuarine water and its associated plankton. One such treatment represented a “natural” scenario in which stable apex predatory pressure was qualified. Water samples were collected over time from each of the treatments for bacterial community evaluation. These samples were assessed through pyrosequencing of the variable regions 4 and 5 of the bacterial 16S rRNA gene and analysed at the species operational taxonomic unit (OTU) level using a community procedure. The blue-green group dominated the samples, followed by Proteobacteria and Bacteroidetes. Samples were the most similar among treatments at the commencement of the experiment. While the bacterial communities sampled within each treatment changed over time, the deviation from initial appeared to be linked to the treatment trophic scenarios. The least temporal deviation-from-initial in bacterial community was found within the stable apex predatory pressure treatment. These findings are consistent with trophic cascade theory, whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity.
- Full Text: false
- Date Issued: 2015
Preparation and use of maize tassels’ activated carbon for the adsorption of phenolic compounds in environmental waste water samples
- Olorundare, O F, Msagati, T A M, Okonkwo, J O, Krause, Rui W M, Mamba, Bhekie B
- Authors: Olorundare, O F , Msagati, T A M , Okonkwo, J O , Krause, Rui W M , Mamba, Bhekie B
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125331 , vital:35773 , https://doi.org/10.1007/s11356-014-3742-6
- Description: The determination and remediation of three phenolic compounds bisphenol A (BPA), ortho-nitrophenol (o-NTP), parachlorophenol (PCP) in wastewater is reported. The analysis of these molecules in wastewater was done using gas chromatography (GC) × GC time-of-flight mass spectrometry while activated carbon derived from maize tassel was used as an adsorbent. During the experimental procedures, the effect of various parameters such as initial concentration, pH of sample solution, eluent volume, and sample volume on the removal efficiency with respect to the three phenolic compounds was studied. The results showed that maize tassel produced activated carbon (MTAC) cartridge packed solid-phase extraction (SPE) system was able to remove the phenolic compounds effectively (90.84–98.49 %, 80.75–97.11 %, and 78.27–97.08 % for BPA, o-NTP, and PCP, respectively) . The MTAC cartridge packed SPE sorbent performance was compared to commercially produced C18 SPE cartridges and found to be comparable. All the parameters investigated were found to have a notable influence on the adsorption efficiency of the phenolic compounds from wastewaters at different magnitudes.
- Full Text:
- Date Issued: 2015
- Authors: Olorundare, O F , Msagati, T A M , Okonkwo, J O , Krause, Rui W M , Mamba, Bhekie B
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125331 , vital:35773 , https://doi.org/10.1007/s11356-014-3742-6
- Description: The determination and remediation of three phenolic compounds bisphenol A (BPA), ortho-nitrophenol (o-NTP), parachlorophenol (PCP) in wastewater is reported. The analysis of these molecules in wastewater was done using gas chromatography (GC) × GC time-of-flight mass spectrometry while activated carbon derived from maize tassel was used as an adsorbent. During the experimental procedures, the effect of various parameters such as initial concentration, pH of sample solution, eluent volume, and sample volume on the removal efficiency with respect to the three phenolic compounds was studied. The results showed that maize tassel produced activated carbon (MTAC) cartridge packed solid-phase extraction (SPE) system was able to remove the phenolic compounds effectively (90.84–98.49 %, 80.75–97.11 %, and 78.27–97.08 % for BPA, o-NTP, and PCP, respectively) . The MTAC cartridge packed SPE sorbent performance was compared to commercially produced C18 SPE cartridges and found to be comparable. All the parameters investigated were found to have a notable influence on the adsorption efficiency of the phenolic compounds from wastewaters at different magnitudes.
- Full Text:
- Date Issued: 2015
Privilege, solidarity and social justice struggles in South Africa: a view from Grahamstown
- Authors: Matthews, Sally
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142270 , vital:38064 , DOI:10.1353/trn.2015.0016
- Description: The last decade has seen a significant increase in the number and prominence of social movements in South Africa. Many of these movements are supported by relatively privileged individuals who are not themselves victims of the injustices the movements oppose. In this paper, I draw out some of the possibilities and limitations of the role of privileged individuals in supporting social movements struggling for social justice, looking particularly at the role of students in supporting such movements. The paper is based on research on the relationship between one such movement, the Unemployed People’s Movement (UPM), and a student organisation, the Students for Social Justice (SSJ), both of which are based in Grahamstown, South Africa. While acknowledging that privileged supporters of such movements can play a constructive role in social justice struggles, I use the experiences of the UPM and SSJ to explore some of the tensions that are likely to emerge and that need to be addressed when the relatively privileged participate in popular struggles. In particular, I discuss the likely difficulties privileged supporters will experience in bridging social divides and in contributing meaningfully to the theorisation of popular struggles.
- Full Text:
- Date Issued: 2015
- Authors: Matthews, Sally
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142270 , vital:38064 , DOI:10.1353/trn.2015.0016
- Description: The last decade has seen a significant increase in the number and prominence of social movements in South Africa. Many of these movements are supported by relatively privileged individuals who are not themselves victims of the injustices the movements oppose. In this paper, I draw out some of the possibilities and limitations of the role of privileged individuals in supporting social movements struggling for social justice, looking particularly at the role of students in supporting such movements. The paper is based on research on the relationship between one such movement, the Unemployed People’s Movement (UPM), and a student organisation, the Students for Social Justice (SSJ), both of which are based in Grahamstown, South Africa. While acknowledging that privileged supporters of such movements can play a constructive role in social justice struggles, I use the experiences of the UPM and SSJ to explore some of the tensions that are likely to emerge and that need to be addressed when the relatively privileged participate in popular struggles. In particular, I discuss the likely difficulties privileged supporters will experience in bridging social divides and in contributing meaningfully to the theorisation of popular struggles.
- Full Text:
- Date Issued: 2015
Reconsidering research ethics in ethnographic research: bearing witness to ‘irreparable harm’
- Barker, Kim, Macleod, Catriona I
- Authors: Barker, Kim , Macleod, Catriona I
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143805 , vital:38284 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Research with persons who have experienced trauma requires careful consideration. In preparing the ethics protocol for an ethnographic study of an anti-rape protest, we thought carefully about how the first author would manage ethical decisions in accordance with the University ethics code. However, this process did not prepare us for the dynamic and reciprocal positioning the first author encountered in the field. Nor was she prepared for her sense of the ethical duty of response when entrusted with the narratives of women who had suffered ‘irredeemable harm’. Drawing on the philosophy of Emmanuel Levinas, and examples from the research, we show how ethical decision-making in ethnographic research is always relational and dialogical; extending beyond our direct interactions with participants to the ways in which we approach our ‘data’. We argue that ethics cannot be reduced to a cognitive-rational process and propose ways to acknowledge and draw on the ‘affective’ and ‘transcendent’ in our ethical decision-making.
- Full Text:
- Date Issued: 2015
- Authors: Barker, Kim , Macleod, Catriona I
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143805 , vital:38284 , https://ischp.files.wordpress.com/2015/08/ischp_2015_abstract_booklet.pdf
- Description: Research with persons who have experienced trauma requires careful consideration. In preparing the ethics protocol for an ethnographic study of an anti-rape protest, we thought carefully about how the first author would manage ethical decisions in accordance with the University ethics code. However, this process did not prepare us for the dynamic and reciprocal positioning the first author encountered in the field. Nor was she prepared for her sense of the ethical duty of response when entrusted with the narratives of women who had suffered ‘irredeemable harm’. Drawing on the philosophy of Emmanuel Levinas, and examples from the research, we show how ethical decision-making in ethnographic research is always relational and dialogical; extending beyond our direct interactions with participants to the ways in which we approach our ‘data’. We argue that ethics cannot be reduced to a cognitive-rational process and propose ways to acknowledge and draw on the ‘affective’ and ‘transcendent’ in our ethical decision-making.
- Full Text:
- Date Issued: 2015
Reflecting on patient-centred care in pharmacy through an illness narrative:
- Authors: Dowse, Roslind
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156687 , vital:40038 , https://0-doi.org.wam.seals.ac.za/10.1007/s11096-015-0104-5
- Description: Patient-centred care (PCC) is rapidly adopting a central position in discussions on the quality of healthcare, with patient-centredness deemed essential to transforming the healthcare system. PCC speaks to the quality of patient-provider relationships and has been defined as an approach to providing care that is respectful of and responsive to individual patient preferences, needs, and values, while ensuring that patient values guide all clinical decisions. However its place within pharmacy practice is unclear and is as yet undefined, particularly in relation to pharmaceutical care. Through my personal illness narrative, I briefly explore the visibility and evidence of PCC in the pharmacy literature as well as from personal experience of pharmacy care, and find it lacking. I conclude that an integrated, seamless understanding of PCC and the use of shared language within the health professions is essential in successful teamwork with both the patient and with other health professions.
- Full Text:
- Date Issued: 2015
- Authors: Dowse, Roslind
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/156687 , vital:40038 , https://0-doi.org.wam.seals.ac.za/10.1007/s11096-015-0104-5
- Description: Patient-centred care (PCC) is rapidly adopting a central position in discussions on the quality of healthcare, with patient-centredness deemed essential to transforming the healthcare system. PCC speaks to the quality of patient-provider relationships and has been defined as an approach to providing care that is respectful of and responsive to individual patient preferences, needs, and values, while ensuring that patient values guide all clinical decisions. However its place within pharmacy practice is unclear and is as yet undefined, particularly in relation to pharmaceutical care. Through my personal illness narrative, I briefly explore the visibility and evidence of PCC in the pharmacy literature as well as from personal experience of pharmacy care, and find it lacking. I conclude that an integrated, seamless understanding of PCC and the use of shared language within the health professions is essential in successful teamwork with both the patient and with other health professions.
- Full Text:
- Date Issued: 2015